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Acquisition of noun modifiers : the relative clause and descriptive adjective Lippman, Marica Zoe 1970

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THE ACQUISITION OF NOUN MODIFIERS: THE RELATIVE CLAUSE AND DESCRIPTIVE ADJECTIVE by Marcia Zoe Lippman M.A., Michigan State University, 1966 A THESIS SUBMITTED IN PARTIAL FULFILMENT OF THE REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY in the Department of Psychology We accept this thesis as conforming to the required standard THE UNIVERSITY OF BRITISH COLUMBIA August, 1970 In presenting t h i s thesis in p a r t i a l f u l f i l m e n t of the requirements for an advanced degree at the University of B r i t i s h Columbia, I agree that the Library shall make i t f r e e l y available for reference and study. I further agree that permission for extensive copying of t h i s thesis for scholarly purposes may be granted by the Head of my Department or by his representatives. It i s understood that copying or publication of this thesis f o r f i n a n c i a l gain shall not be allowed without my written permission. Department of Psychology The University of B r i t i s h Columbia Vancouver 8, Canada Date September 2, 1970 l i A b s t r a c t Spontaneous p r o d u c t i o n . I m i t a t i o n , and Comprehens ion p r o c e d u r e s were u s e d t o (a) i n v e s t i g a t e the a c q u i s i t i o n o f t he a d j e c t i v a l r e l a t i v e c l a u s e and d e s c r i p t i v e a d j e c t i v e , and (b) t o examine the p r e d i c t i v e adequacy o f two p e r f o r m a n c e m o d e l s , t he Yngve Depth H y p o t h e s i s and T r a n s f o r m a -t i o n H y p o t h e s i s . Ave rage mean d e p t h and number o f t r a n s f o r m a t i o n a l o p e r a t i o n s were u s e d as p r e d i c t i v e i n d i c e s . S u b j e c t s were 20 n u r s e r y s c h o o l c h i l d r e n , d i v i d e d i n t o two g roups o f 10 e a c h , Group 2-3 (mean age 3.6 y e a r s ) and Group A-5 (mean age 5.0 y e a r s ) . S u b j e c t s were i n d i v i d u a l l y t e s t e d i n t h r e e t o f i v e s e s s i o n s on a l l t h r e e p r o c e d u r e s and on two t a s k s w i t h i n e a ch p r o c e d u r e . S t i m u l i c o n s i s t e d o f two s e t s o f s e n t e n c e s and p i c t u r e s , T a s k 1 and T a s k 2. Task 1 c o n s i s t e d o f 36 s e n t e n c e s wh i ch v a r i e d a c c o r d i n g t o t h r e e c r i t e r i a : S yn tax ( r e l a t i v e o r s i m p l e ) ; Embeddedness [end-(2 l e v e l s ) o r s e l f - e m b e d d e d ] ; and P ronoun Use ( s u b j e c t , o b j e c t o r o b j e c t o f p r e p o s i t i o n ) . T a s k 2 c o n s i s t e d o f 96 s e n t e n c e s wh i ch v a r i e d a c c o r d i n g t o t h r e e c r i t e r i a : Syn tax ( a d j e c t i v e , r e l a t i v e o r s i m p l e ) ; Type o f a d j e c t i v e (base o r d e r i v e d ) ; and Embeddedness [end-(3 l e v e l s ) o r s e l f -embedded] . C o r r e s p o n d i n g t o each s e n t e n c e c o n t e n t was a s e t o f f o u r p i c t u r e s (Task 1) o r p a i r s o f p i c t u r e s (Task 2) wh i ch s e r v e d as r e s p o n s e a l t e r n a t i v e s d u r i n g t h e Comprehens ion P r o c e d u r e . S i x t y o f the p i c t u r e s were a l s o u s e d as s t i m u l u s m a t e r i a l s f o r Spontaneous P r o d u c t i o n . D e p e n -dent measures were number c o r r e c t ( I m i t a t i o n and C o m p r e h e n s i o n ) , l a t e n c y (Comprehens i on ) , number o f r e s p o n s e s i n t h r e e e r r o r c a t e g o r i e s (Task 1 C o m p r e h e n s i o n ) , and p e r c e n t a g e o f r e s p o n s e s i n 12 e r r o r c a t e g o r i e s ( I m i t a t i o n ) . Spontaneous p r o d u c t i o n r e s u l t s were p r e s e n t e d by e x a m p l e s . Age was f o u n d t o be a h i g h l y s i g n i f i c a n t f a c t o r i n a l l a n a l y s e s o f number c o r r e c t f o r b o t h t a s k s and p r o c e d u r e s , Group 2-3 p e r f o r m i n g p o o r e r i i i than Group 4-5. On Tasks 1 and 2, Syntax and Embeddedness were s i g n i f i -cant factors for Imitation but not Comprehension (number correct). On the Task 1 Imitation Procedure, a Simple > Relative ordering of Syntax means was obtained which was consistent with predictions from both models. On Task 2, however, the obtained Adjective > Simple > Relative ordering of Syntax means was consistent with the predictions made from the Depth Hypothesis but not those made from the Transformation Hypothesis. Adjec-tive sentences were expected to be more d i f f i c u l t than Relative according to the latter hypothesis. The finding of poorer performance on s e l f -embedded Relative sentences than on end-embedded or control Simple sen-tences on Tasks 1 and 2 for Imitation was also consistent with only the Depth Hypothesis, the Transformation Hypothesis predicting no differences since the sentences did not di f f e r in type or number of transformations. Results of the Comprehension and Imitation Procedures allowed for ordering of means according to d i f f i c u l t y but revealed l i t t l e about the early form of knowledge of single- or multiple-word modifiers. Qualita-tive analysis of imitation errors and spontaneous production data proved more f r u i t f u l . It was found that (1) the Noun Phrase + with + Noun Phrase and Noun Phrase + participle phrase were earlier occurring forms of mul-tiple-word noun modification than the relative clause; (2) the relative clause did not precede the descriptive adjective in production as would be expected on the basis of the Transformation Hypothesis; (3) even the oldest Ss showed l i t t l e differentiation of the relative pronoun in imita-tion or spontaneous production; and (4) self-embedded relative clause sentences never occurred in the spontaneous production protocols. Few errors were made in imitation of Adjective sentences or in spontaneous production; a l l Ss used adjectives in the nominal productively. It was concluded that neither performance model allowed for adequate iv d e s c r i p t i o n o r p r e d i c t i o n o f p e r f o r m a n c e . The Yngve mode l i g n o r e s t he r e l a t i o n s h i p between s e n t e n c e s o f d i f f e r i n g s t r u c t u r e and the T r a n s f o r m a -t i o n mode l f a i l s t o t a k e i n t o a c c o u n t t h e s e q u e n t i a l n a t u r e o f p r o d u c -t i o n and c o m p r e h e n s i o n . F e a t u r e s o f a more adequa te mode l were d i s c u s s e d . V Table of Contents T i t l e i Abstract • i i Table of Contents • • v List of Tables v i List of Figures # ix List of Appendices . x Acknowledgements . x i Chapter One. Introduction 1 Chapter Two. The Purpose of the Study 25 Chapter Three. Quantitative Data 49 Task 1 49 Method 49 Results and Discussion. 58 Task 2 95 Method 95 Results and Discussion 103 Chapter Four. Qualitative Data • 132 Method 134 Results and Discussion 138 Chapter Five. General Discussion... 169 Chapter Six. Summary 179 References 184 v i L i s t o f T a b l e s I. 1. Sample T a s k 1 Sen t ences f o r Comprehens ion and I m i t a t i o n P r o c e d u r e s 51 I I . 2. Ave r age Mean Depth f o r Sen tences R e p r e s e n t i n g each S y n t a x , Embeddedness and P ronoun Use C o n d i t i o n o n T a s k 1 55 I I I . 3. Summary o f A n a l y s i s o f V a r i a n c e o f C o r r e c t Comprehens ion Responses f o r Two Age Groups (A) Taken as Repea ted Measures o n Syn tax (B) 60 IV . 4 . Summary o f A n a l y s i s o f V a r i a n c e o f C o r r e c t Comprehens ion Responses on R e l a t i v e Sen t ences f o r Two Age Groups (A) Taken a s Repea ted Measu res on Embeddedness (B) and P ronoun Use (C) 63 V . 5. Summary o f A n a l y s i s o f V a r i a n c e o f C o r r e c t Comprehens ion Responses o n S i m p l e Sen tences f o r Two Age Groups (A) Taken as Repea ted Measu res on Embeddedness (B) and P ronoun Use (C) 66 V I . 6. Summary o f T h r e e A n a l y s e s o f V a r i a n c e o f C o r r e c t Comprehens ion Responses by Group 2-3 on Embed-dedness C o n d i t i o n s V , 0 and S f o r Age (A) and S yn tax (B) Taken as Repea ted Measu res on B 68 V I I . 7. Summary o f Two A n a l y s e s o f V a r i a n c e o f C o r r e c t Comprehens ion Responses by Group 2-3 on P ronoun Uses (o) and (p) f o r Age (A) and S yn tax (B) Taken as Repeated Measu res o n B 72 V I I I . 8. Summary o f A n a l y s i s o f V a r i a n c e o f L a t e n c y o f Comprehens ion Responses f o r Two Age Groups (A) Taken as Repea ted Measures on Syntax (B) 75 IX. 9 . Number o f M, R and R-M Comprehens ion E r r o r s f o r Group 2-3 on R e l a t i v e Sen t ences 78 X . 1 0 . Summary o f A n a l y s i s o f V a r i a n c e o f C o r r e c t I m i t a t i o n Responses f o r Two Age Groups (A) Taken as Repea ted Measures on Syntax (B) 81 X I . 1 1 . Summary o f A n a l y s i s o f V a r i a n c e o f C o r r e c t I m i t a t i o n Responses on R e l a t i v e Sen tences by Group 4-5 f o r Embeddedness (B) and P ronoun Use (C) 83 X I I . 12 . Summary o f A n a l y s i s o f V a r i a n c e o f C o r r e c t I m i t a t i o n Responses on S i m p l e Sen t ences by Group 4-5 f o r Embeddedness (B) and P ronoun Use (C) 87 vii X I I I . 1 3 . Summary o f T h r e e A n a l y s e s o f V a r i a n c e o f C o r r e c t I m i t a t i o n Responses by Group 4-5 on Embeddedness C o n d i t i o n s V , 0 and S f o r Syn tax ( B ) . . . « 88 X IV . 14 . Summary o f T h r e e A n a l y s e s o f V a r i a n c e o f C o r r e c t I m i t a t i o n Responses by Group 4-5 on P ronoun Uses ( s ) , (p) and (o) f o r S yn tax (B) 90 XV. 1 5 . Number o f C o r r e c t Responses f o r e a ch S u b j e c t on T a s k 1 Comprehens ion and I m i t a t i o n P r o c e d u r e s . . 92 X V I . 1 6 . Summary o f R e s u l t s on T a s k 1 Comprehens ion and I m i t a t i o n P r o c e d u r e s 94 X V I I . 1 7 . Sample T a s k 2 Sen t ences f o r Comprehens ion and I m i t a t i o n P r o c e d u r e s 98 X V I I I . 18 . A v e r a g e Mean D e p t h f o r Sen t ences R e p r e s e n t i n g e a ch Syn tax and Embeddedness C o n d i t i o n on T a s k 1 101 X IX . 1 9 . Summary o f A n a l y s i s o f V a r i a n c e o f C o r r e c t Comprehens ion Responses f o r Two Age Groups (A) T a k e n a s Repea ted Measu res o n T y p e (B) and Syn tax (C) 105 XX. 20 . Summary o f A n a l y s i s o f V a r i a n c e o f C o r r e c t Comprehens ion Responses by Group 2-3 f o r Type (B ) , S yn t ax (C) and Embeddedness (D) 107 XX I . 2 1 . Summary o f A n a l y s i s o f V a r i a n c e o f C o r r e c t Comprehens ion Responses o n S i m p l e Sen t ences by Group 2-3 f o r Type (B) and Embeddedness (C) 110 XX I I . 2 2 . Summary o f A n a l y s i s o f V a r i a n c e o f L a t e n c y o f Comprehens ion Responses f o r Two Age Groups (A) Taken a s Repea ted Measures on Syn tax (B) 113 XX I I I . 2 3 . Summary o f A n a l y s i s o f V a r i a n c e o f C o r r e c t I m i t a t i o n Responses f o r Two Age Groups (A) Taken a s Repea ted Measu res on Type (B) and Syn tax (C) . 116 XXIV. 24 . Summary o f A n a l y s i s o f V a r i a n c e o f C o r r e c t I m i t a t i o n Responses by Group 2-3 f o r Type ( B ) , Syn tax (C) and Embeddedness (D) 122 XXV. 2 5 . Summary o f A n a l y s i s o f V a r i a n c e o f C o r r e c t I m i t a t i o n Responses on S imp l e S en t ences by Group 2-3 f o r Type (B) and Embeddedness (C) 124 XXV I . 26 . Summary o f F o u r A n a l y s e s o f V a r i a n c e o f C o r r e c t I m i t a t i o n Responses by Group 2-3 o n Embeddedness C o n d i t i o n s V , P, 0 and S f o r T y p e (B) and Syn tax ( C ) . . 126 v i i i XXV I I . 2 7 . Number o f C o r r e c t Responses f o r e a c h S u b j e c t on T a s k 2 Comprehens ion and I m i t a t i o n P r o c e d u r e s 129 XXV I I I . 2 8 . Summary o f R e s u l t s o n Taek 2 Comprehens ion and I m i t a t i o n P r o c e d u r e s 130 XXIX . 2 9 . P e r c e n t a g e o f I m i t a t i o n s i n each o f 10 C a t e g o r i e s o n T a s k 1 f o r R e l a t i v e and S imp l e S e n t e n c e s . . 139 XX. 3 0 . P e r c e n t a g e o f I m i t a t i o n s i n e a ch o f 12 C a t e g o r i e s on T a s k 2 f o r R e l a t i v e and S i m p l e Sen t ences 140 XXX I . 31 . R e l a t i v e P ronoun S u b s t i t u t i o n s f o r T a s k 1 I m i t a t i o n P r o c e d u r e . . . . . 144 XXX I I . 32 . R e l a t i v e P ronoun S u b s t i t u t i o n s f o r T a s k 2 I m i t a t i o n P r o c e d u r e 148 XXX I I I . 3 3 . P e r c e n t a g e o f I m i t a t i o n s i n each o f 12 C a t e -g o r i e s on T a s k 2 f o r A d j e c t i v e S e n t e n c e s . 158 XXXIV. 3 4 . C o n t e x t s o f N o m i n a l A d j e c t i v e s f o r F o u r S u b j e c t s . . . . . . . 162 XXXV. 3 5 . Examples o f P i c t u r e D e s c r i p t i o n s by Two Group 2-3 and Two Group 4-5 S u b j e c t s 165 XXXVI . 3 6 . A d j e c t i v e s P r o d u c e d i n Spontaneous S p e e c h . . . 167 i x L i s t o f F i g u r e s 1. Mean Number o f C o r r e c t Responses on T a s k 1 Comprehens ion P r o c e d u r e f o r R e l a t i v e and S i m p l e Sen tences as a F u n c t i o n o f Age 59 2. Mean Number o f C o r r e c t Responses on T a s k 1 Comprehens ion P r o c e d u r e f o r R e l a t i v e and S i m p l e C o n t r o l S en tences as a F u n c t i o n o f Embeddedness 64 3. Mean Number o f C o r r e c t Responses on T a s k 1 Comprehens ion P r o c e d u r e f o r R e l a t i v e and S i m p l e C o n t r o l S en t ences as a F u n c t i o n o f P ronoun Use 65 4 . Mean L a t e n c y o f Response on T a s k 1 Comprehens ion P r o c e -du r e f o r R e l a t i v e and S i m p l e S e n t e n c e s as a F u n c t i o n o f Age 75 5. Mean Number o f C o r r e c t Responses on T a s k 1 I m i t a t i o n P r o c e d u r e f o r R e l a t i v e and S i m p l e Sen t ences as a F u n c -t i o n o f Age 80 6 . Mean Number o f C o r r e c t Responses on T a s k 1 I m i t a t i o n P r o c e d u r e f o r R e l a t i v e and S i m p l e C o n t r o l S en t ences a s a F u n c t i o n o f Embeddedness 84 7. Mean Number o f C o r r e c t Responses on T a s k 1 I m i t a t i o n P r o c e d u r e f o r R e l a t i v e and S i m p l e C o n t r o l S en t ences as a F u n c t i o n o f P ronoun Use 86 8. Mean Number o f C o r r e c t Responses on T a s k 2 Comprehens ion P r o c e d u r e f o r Base A d j e c t i v e , R e l a t i v e and S i m p l e S e n -t e n c e s ( l e f t ) and f o r D e r i v e d A d j e c t i v e and C o n t r o l S e n -t e n c e s ( r i g h t ) as a F u n c t i o n o f Age 104 9. Mean Number o f C o r r e c t Responses on T a s k 2 Comprehens ion P r o c e d u r e f o r A d j e c t i v e , R e l a t i v e and S i m p l e C o n t r o l S e n t e n c e s as a F u n c t i o n o f Embeddedness 109 1 0 . Mean L a t e n c y o f Response on T a s k 2 Comprehens ion P r o c e -du r e f o r A d j e c t i v e , R e l a t i v e and S i m p l e Sen t ences as a F u n c t i o n o f Age 112 1 1 . Mean Number o f C o r r e c t Responses on T a s k 2 I m i t a t i o n P r o c e d u r e f o r Base A d j e c t i v e , R e l a t i v e and S i m p l e Sen t ences ( l e f t ) and f o r D e r i v e d A d j e c t i v e and C o n t r o l S en t ences ( r i g h t ) as a F u n c t i o n o f Age 115 1 2 . Type X S yn tax I n t e r a c t i o n 117 1 3 . Age X S yn tax I n t e r a c t i o n 119 14 . Mean Number o f C o r r e c t Responses on T a s k 2 I m i t a t i o n P r o c e d u r e f o r Base A d j e c t i v e , R e l a t i v e and S i m p l e S e n -t e n c e s ( l e f t ) and f o r D e r i v e d A d j e c t i v e and C o n t r o l S en t ences ( r i g h t ) as a F u n c t i o n o f Embeddedness 121 X L i s t o f A p p e n d i c e s A p p e n d i x A T a s k 1 and T a s k 2 S en t ences 190 A p p e n d i x B Sample T a s k 1 and T a s k 2 P i c t u r e s 199 Acknowledgmen ts The author wishes to thank Dr. Arthur Reber, chairman of the doc-toral committee, for his assistance and encouragement. Special thanks are also due Dr. Chris Tragakis. Other members of the committee, Dr. John Yuille, Dr. Richard Tees, and Dr. Fred Bower, are thanked for their c r i t i c a l reading of the dissertation. In addition, the author wishes to acknowledge the cooperation and assistance of the director and staff of the Holly Lynn Nursery School, Bellingham, Washington. I n t r o d u c t i o n The s t u d y o f l a n g u a g e a c q u i s i t i o n w i t h i n t he f ramework o f d e v e l o p -m e n t a l p s y c h o l o g y , s p e e c h p a t h o l o g y , o r commun i ca t i on i s n o t new by any means ( e . g . , M c C a r t h y , 1 9 5 4 ) . W i t h i n t h e s e f rameworks t h e s t u d y o f l anguage a c q u i s i t i o n c e n t e r e d o n s u c h pe r f o rmance changes as s e n t e n c e l e n g t h and v o c a b u l a r y i n c r e m e n t s . A s h i f t i n a t t e n t i o n f r om p e r f o r m a n c e ' t o compe tence , o r t h e l anguage u s e r ' s i m p l i c i t knowledge o f h i s l a n g u -a g e , has r e c e n t l y t a k e n p l a c e w i t h i n t h e r u b r i c o f p s y c h o l i n g u i s t i c s . W i th t h e s h i f t i n a t t e n t i o n has come a q u i t e d i f f e r e n t d e f i n i t i o n o f t h e p r o b l e m o f a c q u i s i t i o n . M a j o r a c h i e v e m e n t s i n t h e p r e s c h o o l y e a r s i n -c l u d e n o t o n l y t h e c h i l d ' s a c q u i s i t i o n o f new v o c a b u l a r y b u t h i s a b i l i t y t o c o n s t r u c t i v e l y u se h i s newly a c q u i r e d v o c a b u l a r y t o p r o d u c e and u n d e r s t a n d a g r e a t v a r i e t y o f u t t e r a n c e s . To a c c o u n t f o r t h i s l a t t e r a b i l i t y , t h e p s y c h o l i n g u i s t s have f o c u s e d o n t h e c h i l d ' s a c q u i s i t i o n o f knowledge abou t t he s t r u c t u r e o f l a n g u a g e . Emphas i s o n t h e s t r u c t u r e o f l a n g u a g e as an i m p o r t a n t key t o u n d e r s t a n d i n g l anguage deve lopment h a s l a r g e l y been t h e r e s u l t o f r e c e n t i n n o v a t i o n s i n l i n g u i s t i c t h e o r y (Chomsky, 1957 , 1965 ; H a r r i s , 1 9 5 7 ) . These d e v e l o p m e n t s , p a r t i c u l a r l y t hose o f Chomsky, have had a p r o f o u n d e f f e c t o n t h e p s y c h o l o g i c a l s t u d y o f l a n g u a g e ( c f . , Sm i th & M i l l e r , 1 9 6 6 ) . T h r e e i n t e r d e p e n d e n t p o s t u l a t e s abou t t h e n a t u r e o f t h e l anguage u s e r and t h e n a t u r e o f t he i m p l i c i t knowledge t h e l a n g u a g e u s e r a c q u i r e s about s t r u c t u r e have i n f l u e n c e d t h e d i r e c t i o n o f r e c e n t l a n g u a g e a c q u i -s i t i o n r e s e a r c h and t h e i n t e r p r e t a t i o n s g i v e n to d a t a . These p o s t u l a t e s r e p r e s e n t t h e outcome o f j o i n t work by p s y c h o l o g i s t s and l i n g u i s t s . 1. Speech p r e c e p t i o n and p r o d u c t i o n a r e r u l e - g o v e r n e d , c o n s t r u c -t i v e p r o c e s s e s ; 2. The l anguage u s e r i n t e r n a l i z e s a s e t o f g e n e r a t i v e grammar r u l e s 2 of the type proposed by Chomsky, specifically, (a) context-sensitive phrase-structure rules and (b) transformation rules; 3. The child brings to the task of language learning an innate propensity for learning the kinds of rules l i s t e d i n 2. Postulate 1. Perhaps the most basic of these postulates Is the f i r s t which states that the language user internalizes a set of implicit rules which govern his actual l i n g u i s t i c performance. That i s , linguis-t i c behaviors are rule-governed. The most compelling argument for this position i s based on the observation that a great proportion of the sen-tences the user hears and speaks are novel combinations (Miller, Galanter, & Pribram, 1960; Miller, 1965). Miller has dramatically pointed out that a Markovian left-to-right model of sentence generation or a learn-ing analysis based on such a model simply cannot parsimoniously account for the novelty of speech at the present time. Memory and time impose limits on the number of patterns that the child can hear and store. He argues that, in principle, only a model of language performance which incorporates a set of generative grammar rules can account for the production and comprehension of sentences never previously spoken or heard. There are some, however, who object to the postulation that speech i s rule-governed (e.g. Fant, 1967; Morton & Broadbent, 1967; Staats, 1968). Morton and Broadbent question the v a l i d i t y of one of Miller's main arguments for the postulation of rule-governed performance, namely, that memory imposes limits on the number of patterns that can be stored. They argue that the efficiency gained by the use of rules in mechanical systems may not be c r i t i c a l to processing by the central nervous system. They propose a passive model of perception which they claim can account for the evidence generally cited as favoring a rule-governed model. Staats, on the other hand, has attempted to rebutt Miller's challenge 3 o f t he c a p a b i l i t y o f a l e a r n i n g a n a l y s i s o f l anguage a c q u i s i t i o n t o a c c o u n t f o r n o v e l s e n t e n c e p r o d u c t i o n . S t a a t s a r g u e s t h a t " w i t h t h e c o n c e p t s o f r e s p o n s e h i e r a r c h i e s , word a s s o c i a t i o n s end complex e n v i r o n -m e n t a l s t i m u l u s c o n t r o l , t he way In wh i ch p a s t l e a r n i n g p r o d u c e s n o v e l s e n t e n c e g e n e r a t i o n can e a s i l y be s e e n . " The f r u i t f u l n e s s o f t he l e a r n i n g o r o f t h e M o r t o n and B roadbent a p p r o a c h i n g e n e r a t i n g h y p o t h e s e s abou t a c q u i s i t i o n and i n s t i m u l a t i n g e m p i r i c a l work has y e t t o be d e m o n s t r a t e d . The f r u i t f u l n e s s o f t he r u l e - g o v e r n e d a p p r o a c h has a l r e a d y been d e m o n s t r a t e d ( e . g . , Brown & B e l l u g l , 1964 ; Brown, 1968 ; Menyuk, 1969 ; M c N e i l l , 1966) a n d , i n g e n e r a l , the d a t a s u p p o r t t h e n o t i o n t h a t s p e e c h p e r c e p t i o n and p r o d u c t i o n a r e r u l e - g o v e r n e d p r o c e s s e s ( c f . , D i x o n & H o r t o n , 1968 ) . P o s t u l a t e 2. The s e c o n d p o s t u l a t e b a s i c t o t h e p s y c h o l l n g u i s t i c a p p r o a c h t o l anguage a c q u i s i t i o n c o n c e r n s t h e n a t u r e o f t h e s e t o f r u l e s o r "g rammar" h y p o t h e s i z e d t o g o v e r n the l anguage u s e r ' s p e r f o r m a n c e . The r e q u i r e m e n t s t h a t s u c h a s e t o f r u l e s , t h e o r e t i c a l l y , must s a t i s f y may be s p e c i f i e d as f o l l o w s . The grammar must be a b l e t o g e n e r a t e an i n f i n i t e s e t o f s e n t e n c e s b u t o n l y t h o s e wh i ch a r e g r a m m a t i c a l . The k i n d s o f r u l e s p o s t u l a t e d must be r e p r e s e n t a t i v e o f t he fo rm t h a t t he competence o f any l anguage u s e r m i g h t t a k e . Tha t i s , t h e grammar must r e f l e c t t h o s e a s p e c t s o f l i n g u i s t i c knowledge wh i ch a r e common t o a l l l a n g u a g e s . F i n a l l y , t h e grammar must be o f s u f f i c i e n t s i m p l i c i t y t h a t a d e v i c e w i t h a f i n i t e memory c o u l d l e a r n the r u l e s i n a r e a s o n a b l e p e r i o d o f t i m e . Two grammar mode l s have been c o n s i d e r e d as c a n d i d a t e s f o r r e p r e -s e n t i n g the l anguage u s e r ' s competence , one a r e w r i t e s y s t e m , t h e o t h e r a t r a n s f o r m a t i o n s y s t e m . M i l l e r and Chomsky (1963) a r g u e t h a t t h e t r a n s -f o r m a t i o n a l grammar mode l w h i c h i n c l u d e s b o t h c o n t e x t - s e n s i t i v e p h r a s e -s t r u c t u r e r u l e s and t r a n s f o r m a t i o n r u l e s b e s t meets t h e r e q u i r e m e n t s s p e c i f i e d above . A r e q r i t e s y s t em t h a t i d e n t i f i e s t h e c o n s t i t u e n t s o f c o n s t r u c t i o n s and g i v e s t h e o r d e r o f t h e c o n s t i t u e n t s i s c a l l e d a p h r a s e - s t r u c t u r e g rammar . * I t i s a r e w r i t e s y s t em i n t h a t each r u l e i s o f t h e f o r m X >Y, r e a d , " r e w r i t e X a s T . " The s y s t em o f r e w r i t e r u l e s i s h i e r a r c h i c a l as can be s e e n f r o m t h e d e r i v a t i o n be low o f t h e s e n t e n c e , t h e man h i t t h e  b a l l (Chomsky, 1 9 5 7 ) . The symbo l NP s t a n d s f o r noun p h r a s e ; VP s t a n d s f o r v e r b p h r a s e . ( i ) S en t ence > NP + VP ( i i ) NP > T + N ( i l l ) VP • •> V e r b + NP ( i v ) T > the (v ) N — > man, b a l l , e t c . ( v i ) V e r b > h i t , t o o k , e t c . The d e r i v a t i o n may a l s o be r e p r e s e n t e d i n a t r e e d i a g r a m . t h e man h i t t h e b a l l T h e ma jo r l i m i t a t i o n o f t h e r e w r i t e s y s t e m i s t h a t w i t h o u t knowledge o f t h e d e r i v a t i o n o r what has p r e c e d e d a symbo l t o be r e w r i t t e n , u n -g r a m m a t i c a l a s w e l l a s g r a m m a t i c a l s equences may b e g e n e r a t e d (Chomsky, 1 9 5 7 ) . The i n s e n s i t i v i t y o f t h e s i m p l e r e w r i t e s y s t em t o c o n t e x t has • R e l a t e d g r o u p s o f words s u c h a s , t h e man h i t t h e b a l l , o r , t h e man , a r e c a l l e d c o n s t r u c t i o n s . A s u b s e t o f a c o n s t r u c t i o n i s c a l l e d a c o n s t i t u e n t . The man i s a c o n s t i t u e n t o f t h e c o n s t r u c t i o n , t h e man h i t t h e b a l l . 5 been shown In t h e d e r i v a t i o n o f (a) c o n j u n c t i o n s , (b) a s s i gnmen t o f t h e a p p r o p r i a t e v e r b f o r m so a s t o g e n e r a t e s e n t e n c e s w i t h noun-ve rb a g r e e -ment , and ( c ) f o r m a t i o n o f p a s s i v e s ( D i n e e n , 1 9 6 7 ) . C o n s i d e r , f o r e x a m p l e , t h e c h o i c e o f t h e p r o p e r v e r b f o r m i n t h e s e n t e n c e t h e woman has been  s h o p p i n g . I n o r d e r t o r e w r i t e VP i n t h e d e r i v a t i o n so t h a t t h e v e r b a g r e e s w i t h the s i n g u l a r n o u n , i t wou ld be n e c e s s a r y to know t h a t t h e woman i s a NP s i n g u l a r * A c c o r d i n g t o Chomsky (1957) t h e r e i s no way t o i n c o r p o r a t e r u l e s i n a s i m p l e p h r a s e - s t r u c t u r e grammar t h a t wou ld t a k e s u c h I n t e r d e p e n d e n c i e s i n t o a c c o u n t . T h i s i s n o t t o s a y t h a t i t i s i m -p o s s i b l e t o f o r m u l a t e r u l e s w h i c h wou ld c o r r e c t t h e l i m i t a t i o n s o f t h e p h r a s e - s t r u c t u r e grammar b u t o n l y t h a t t h o s e r u l e s c o u l d no t f i t t h e r e q u i r e m e n t s o f t h e s i m p l e p h r a s e - s t r u c t u r e grammar. Chomsky f o u n d i t was n e c e s s a r y to p o s t u l a t e two t y p e s o f r u l e s , c o n -t e n t - s e n s i t i v e p h r a s e - s t r u c t u r e r u l e s and t r a n s f o r m a t i o n r u l e s , t o c o r r e c t t h e l i m i t a t i o n s o f t h e s i m p l e grammar. The t r a n s f o r m a t i o n t y p e o f r u l e f o r m a l l y I n t r o d u c e d b y Chomsky r e p r e s e n t s a new c o n c e p t o f l i n g u i s t i c s t r u c t u r e . T h e s e r u l e s do n o t r e w r i t e g r a m m a t i c a l c a t e g o r i e s I n t o c o n -s t i t u e n t s b u t o p e r a t e upon an e n t i r e c o n s t r u c t i o n ( e . g . , NP^ + V + NP^ becomes NP2 + be +, V-en + b y + NP^ by a p p l i c a t i o n o f t h e p a s s i v e t r a n s -f o r m a t i o n r u l e s ) . I t i s a rgued t h a t t h i s k i n d o f r u l e e n s u r e s t h a t d i s c o n t i n u i t i e s o f i n t e r d e p e n d e n t e l e m e n t s s u c h a s be-en + w i l l n o t r e s u l t i n u n g r a m m a t l c a l u t t e r a n c e s b u t w i l l be p r o p e r l y c o o r d i n a t e d . The mode l o f grammar p r o p o s e d b y Chomsky i n c o r p o r a t e s t h r e e com-p o n e n t s , a p h r a s e - s t r u c t u r e component , a t r a n s f o r m a t i o n a l component end a morphophonemic component . The p h r a s e - s t r u c t u r e component i s an o r d e r e d s e t o f r e w r i t e r u l e s . The s t r i n g o f symbo ls d e r i v e d f r om p h r a s e - s t r u c -t u r e r u l e s i s c a l l e d t h e t e r m i n a l s t r i n g o f t h e k e r n e l o r K - t e r m i n a l s t r i n g . T h i s s t r i n g r e p r e s e n t s t h e deep s t r u c t u r e o f t h e s e n t e n c e w h i c h 6 d e f i n e s a l l t h e b a s i c g r a m m a t i c a l r e l a t i o n s h i p s ( e . g . , s u b j e c t o f , p r e d i -d a t e o f , o b j e c t o f ) . A c c o r d i n g t o Chomsky i t i s i n r e f e r e n c e t o t he deep s t r u c t u r e and t h e b a s i c r e l a t i o n s d e f i n e d by i t t h a t a l l complex s e n t e n c e s a r e u n d e r s t o o d . The t r a n s f o r m a t i o n a l component c o n s i s t s o f r u l e s w h i c h a d d , d e l e t e , o r r e a r r a n g e t h e o r d e r o f t h e morphemes i n t h e t e r m i n a l s t r i n g s p r o d u c e d by t h e p h r a s e - s t r u c t u r e r u l e s . T h e s e r u l e s may a l s o a p p l y to s t r i n g s w h i c h have a l r e a d y been t r a n s f o r m e d by o t h e r t r a n s f o r m a t i o n r u l e s . Some o f t h e t r a n s f o r m a t i o n s a r e o b l i g a t o r y and some o p t i o n a l . The d i s t i n c t i o n w i l l become c l e a r i n t h e example t h a t f o l l o w s . The f i n a l r e s u l t o f t h e a p p l i c a t i o n o f t r a n s f o r m a t i o n r u l e s i s c a l l e d t h e T - t e r m i n a l s t r i n g . I t g i v e s t h e s u r f a c e s t r u c t u r e o f t h e s e n t e n c e . The t r a n s f o r m a t i o n a l h i s t o r y o f t h e q u e s t i o n D i d t h e man l augh ? a s o u t l i n e d by R o b e r t s (1964) w i l l s e r v e t o i l l u s t r a t e t h e manner o f a p p l i c a -t i o n o f t r a n s f o r m a t i o n r u l e s . The Yes/No q u e s t i o n t r a n s f o r m a t i o n , d e s i g -n a t e d T - y e s / n o , i s an o p t i o n a l t r a n s f o r m a t i o n , b u t whenever i t has b e e n a p p l i e d t h e o b l i g a t o r y do t r a n s f o r m a t i o n , T - d o , must b e a p p l i e d . A p p l i -c a t i o n o f t h e p h r a s e - s t r u c t u r e r u l e s t o Sen tence g i v e s t h e K - t e r m i n a l s t r i n g t h e + man + p a s t + l a u g h . To t h e ^ - t e r m i n a l s t r i n g the o p t i o n a l t r a n s f o r m a t i o n T - y e s / n o i s a p p l i e d p r o d u c i n g p a s t + t h e + man + l a u g h . The r e a r r a n g e m e n t o f symbo ls r e s u l t s i n what i s c a l l e d a f l o a t i n g t e n s e i n t h a t t h e r e i s no s t r u c t u r e ( such a s c a n , h a v e , be ) w h i c h c a n c a r r y t h e t e n s e . H e n c e , t h e o b l i g a t o r y T-dp must be a p p l i e d t o add do t o c a r r y t h e t e n s e . T h i s t r a n s f o r m a t i o n p r o d u c e s t he T - t e r m i n a l s t r i n g do -f p a s t + t h e + man + l a u g h . To t h e T - t e r m i n a l s t r i n g w h i c h i s s t i l l o n l y a r e p -r e s e n t a t i o n o f t h e o r d e r o f t h e morphemes, t h e morphophonemic r u l e s must be a p p l i e d t o c o n v e r t t h e r e p r e s e n t a t i o n i n t o t h e s e n t e n c e , D i d t h e man  l a u g h ? 7 "H1* T-ves/no and T-do transformation rules applied i n the example operated upon a single K-terminal string (also called base string). These rules are examples of single-base transformations since they oper-ate upon only one terminal string. A more complex transformation i s the double-base transformation. Two K-terminal or T-terminal strings under-l i e structures having double-base derivational histories such as the possessive, conjunction and relative clause. One i s the matrix string which provides the form of the sentence to be produced. The second i s the insert string containing structures which are to be inserted into the matrix string. Converting the strings to sentence form for i l l u s t r a t i v e purposes, the relationship between the two bases and the f i n a l T-terminal string can be seen (Roberts, 1964): insert: John has a hat. matrix: The hat i s on the table. result: John's hat Is on the table. The possessive morpheme i s defined by the relationship between John and hat contained In the insert. The power of the transformational grammar model i s particularly clear with ambiguous sentences having a double base derivation. The sentence frequently used as an i l l u s t r a t i o n , flying planes can be danger- ous, has a single surface structure. There are two possible meanings that can be assigned to the sentence, however: Flying planes are danger- ous, or flying planes i s dangerous. Only by reference to the deep struc-ture i s i t possible to determine whether flying i s a descriptive adjec-tive or verbal modifier. If i t i s a verbal modifier, the surface struc-ture derives from the two strings planes can be dangerous and the planes  are flying. While i t i s true that the transformational grammar potentially can generate an Infinite number of utterances and only those that are 8 grammatical, i t does not follow directly that this generative grammar i s identical or even similar to the rules of generative grammar that are assumed to be represented i n the user's memory. It i s yet to be shown that the general form of the grammar can account for the sentences of a l l languages, and that context-sensitive phrase-structure rules and transformation rules are not language specific. In addition, i t i s yet to be demonstrated that phrase-structure and transformation rules have psychological relevance for the language user. If rules of the type postulated by Chomsky are a part of the language user's competence, their structuring influence should be reflected i n performance. A number of studies have demonstrated that the phrase-structure of sentences influences Ss' perception and learning of sentential material (Fodor & Sever, 1965; Garret, Bever & Fodor, 1966; Johnson, 1965, 1968). Evidence for the psychological reality of transformation rules, however, is less clear. It i s d i f f i c u l t to separate the effects on performance of surface structure complexity from the influence of transformation history, although, several studies have shown a differential influence of sentences with different transformational histories on behavioral measures (Gough, 1965, 1966; Mehler, 1963; Mehler & Mi l l e r , 1963; Savin & Perchinock, 1965), they have met with some criticism (e.g., Martin & Roberts, 1966). Evidence for the psychological reality of Chomsky's generative grammar rules in children has generally not been obtained through memory or learning experiments, but has been inferred from the results of analy-ses of speech samples (Brown, 196a; Menyuk, 1963, 1964, 1969). Consider-ably more data i s needed to adequately support the postulation that the child's competence can be represented by the type of grammar rules pro-posed by Chomsky. It was to this end that several of the studies to be 9 d i s c u s s e d I n a l a t e r s e c t i o n were u n d e r t a k e n * P o s t u l a t e 3. A t h i r d p o s t u l a t e o f t h e new a p p r o a c h t o l a n g u a g e deve lopment has been p a r t i c u l a r l y i n f l u e n t i a l i n t h e a p p r o a c h t o r e s e a r c h and t h e p r e l i m i n a r y deve lopmen t o f m o d e l s o f p e r f o r m a n c e . R e p r e s e n t i n g t o some e x t e n t t h e r e b i r t h o f p r e - b e h a v i o r i s t i c and p r e - s t r u c t u r a l i s t i c m e n t a l i s m , t h e p o s t u l a t e s t a t e s t h a t t h e c h i l d b r i n g s t o t h e t a s k o f l a n g u a g e l e a r n i n g a n i n n a t e p r o p e n s i t y f o r a c q u i r i n g t h e k i n d s o f r u l e s d i s c u s s e d a b o v e . I n l i n g u i s t i c s , t h i s v i e w p o i n t i s e spoused by Chomsky i n h i s r e f o r m u l a t i o n o f t h e g o a l s o f l i n g u i s t i c t h e o r y . The f o l l o w i n g b r i e f resume o f Chomsky ' s v i e w s c l a r i f i e s t h e r e a s o n i n g b e h i n d t h e p o s t u -l a t i o n o f i n n a t e knowledge o f s t r u c t u r e . A grammar i s r e g a r d e d a s a t h e o r y o f l anguage wh i ch must meet t h e c o n d i t i o n s o f e x p l a n a t o r y adequacy as w e l l a s d e s c r i p t i v e adequacy (Chomsky, 1 9 6 5 ) . A grammar I s s a i d t o be d e s c r i p t i v e l y adequa t e I f I t a s s i g n s s t r u c t u r a l d e s c r i p t i o n s t o s e n t e n c e s , d i s t i n g u i s h i n g between t h e w e l l - f o r m e d and d e v i a n t s e n t e n c e s . F o r Chomsky i t i s n o t enough t o be a b l e t o make s t r u c t u r a l a s s i g n m e n t s f o r t h e s e n t e n c e s o f each n a t u r a l l a n g u a g e b u t t h e more a m b i t i o u s g o a l o f e x p l a n a t o r y adequacy must be a t t a i n e d i n o r d e r to a l l o w f o r t h e f o r m u l a t i o n o f answers t o more a b s t r a c t q u e s t i o n s . Chomsky s e e k s a l i n g u i s t i c t h e o r y w h i c h w i l l p r o v i d e " a n e x p l a n a t o r y h y p o t h e s i s abou t t h e f o r m o f l a n g u a g e as s u c h " ( i b i d . , p . 2 7 ) . The p r o b l e m o f a c h i e v i n g e x p l a n a t o r y adequacy i s equa ted by Chomsky w i t h t h e p r o b l e m o f c o n s t r u c t i n g a t h e o r y o f l a n g u a g e a c q u i s i t i o n . The l a t t e r p r o b l e m i n v o l v e s a c c o u n t i n g f o r t h e c h i l d ' s i n n a t e p r e d i s p o s i t i o n f o r l a n g u a g e . The s o l u t i o n t o b o t h p rob l ems l i e s i n t h e s t u d y o f t h e p r o p e r -t i e s o f grammar common t o a l l n a t u r a l l a n g u a g e s , t he l i n g u i s t i c u n i v e r s a l s . A t h e o r y o f l anguage a s c o n c e i v e d by Chomsky must i n c o r p o r a t e an a c c o u n t o f l i n g u i s t i c u n i v e r s a l s and must a t t r i b u t e i m p l i c i t knowledge o f t h e 10 universale to the child (ibid., p. 27). This vies? has sparked interest i n acquisition i n many linguists and has also colored the interpretations psychologists have given to the question of how language Is acquired. Chomsky attributes innate knowledge to the child but does not clearly specify whether this knowledge i s specific, i.e., a representation of sub-stantive and formal universals,* or whether the innate knowledge i s viewed as a general capacity to acquire l i n g u i s t i c rules. A strong version of the innate postulate has been espoused by McNeill (1966) in an attempt to develop a theory of language acquisition. Following Chomsky, McNeill formulates the major question to be faced by the theorist as follows: What kind of a device would be capable of acquiring a set of generative grammar rules given a sample of primary l i n g u i s t i c data? Schematically the problem i s represented as shown below, where LAD refers to the hypo-thetical language acquisition device and G refers to the set of generative grammar rules. Primary Linguistic Data > LAD McNeill takes the position that the properties of LAD determine the form that G, grammatical competence, w i l l take. The properties of LAD are assumed to include representations of the substantive and formal uni-versals. Acquisition can be explained by appealing to the contents of LAD, i.e., the li n g u i s t i c universals, according to this view. The child simply imposes his knowledge of universals upon the primary l i n g u i s t i c data to arrive at a set of rules specific to the language. A weaker version of the innate structure postulate has been offered by Lenneberg (1967) and others (Fodor, 1966; Slobin, 1966). This version *For treatment of linguistic universals, see Greenberg, 1963. 11 h y p o t h e s i z e s t h a t what t h e c h i l d b r i n g s t o l anguage a c q u i s i t i o n i s a s p e c i e s - s p e c i f i c c a p a c i t y f o r c o g n i t i v e f u n c t i o n i n g , t h e p r o p e n s i t y f o r l anguage b e i n g o n l y one o f t h e consequences o f m a n ' s b i o l o g i c a l i n h e r i -t a n c e . L ennebe rg m a i n t a i n s t h a t u n i v e r s a l p r o p e r t i e s o f grammar a r e s i m p l y a b y - p r o d u c t o f human c o g n i t i v e c a p a c i t i e s . The i n f o r m a t i o n abou t g r a m m a t i c a l s t r u c t u r e i t s e l f i s n o t assumed t o be i n n a t e a s s u g g e s t e d b y M c N e i l l . R a t h e r , b e c a u s e o f man ' s i n n a t e c o g n i t i v e c a p a c i t i e s , t h e r u l e s c o u l d be o f no o t h e r f o r m . More s p e c i f i c a l l y , L ennebe rg s t a t e s . . . t h e fo rms and modes o f c a t e g o r i z a t i o n , t h e c a p a -c i t y o f e x t r a c t i n g s i m i l a r i t i e s f rom p h y s i c a l s t i m u l u s c o n f i g u r a t i o n s o r f rom c l a s s e s o f deepe r s t r u c t u r a l s c h e m a t a , and t h e o p e r a t i n g c h a r a c t e r i s t i c s o f t h e d a t a - p r o c e s s i n g m a c h i n e r y o f t h e b r a i n ( f o r examp l e , t i m e - l i m i t a t i o n s o n t h e r a t e o f i n p u t , r e s o l u t i o n power f o r t h e a n a l y s i s o f I n t e r t w i n e d p a t t e r n s s u c h as n e s t e d d e p e n d e n c i e s , l i m i t s o f s t o r a g e c a p a c i t i e s f o r d a t a t h a t must be p r o c e s s e d s i m u l t a n e o u s l y , e t c . ) a r e p o w e r f u l f a c t o r s t h a t d e t e r m i n e a p e c u l i a r t y p e o f f o rm f o r l a n g u a g e ( L e n n e b e r g , 1967, p. 3 7 5 ) . F o l l o w i n g L e n n e b e r g ' s p o s i t i o n , t h e n a t u r e o f LAD wou ld be c h a r a c t e r -i z e d somewhat d i f f e r e n t l y t h a n by M c N e i l l . The h y p o t h e t i c a l LAD m e d i a t i n g t h e c o n v e r s i o n o f p r i m a r y d a t a to a s e t o f grammar r u l e s wou ld be r e p r e s e n -t e d a s f o l l o w s . LAD a . modes o f c a t e g o r i z a t i o n b . c a p a c i t y f o r e x t r a c t i o n P r i m a r y o f s i m i l a r i t i e s l i n g u i s t i c L i n g u i s t i c > c . l i m i t e d s t o r a g e c a p a c i t y > u n i v e r s a l s Da t a • • > G L e n n e b e r g ' s v i e w c o u l d have c o n s i d e r a b l e impac t upon t h e a p p r o a c h t a k e n i n r e s e a r c h and t h e o r y s i n c e i t t h r e a t e n s t h e d i s t i n c t i o n g e n e r a l l y made between p e r f o r m a n c e and compe tence . F a c t o r s c o n s i d e r e d to be p e r f o r m a n c e v a r i a b l e s such as s t o r a g e c a p a c i t y may i n f a c t be o r g a n i s m i c d e t e r m i n a n t s 12 o f t h e f o rm t h a t l a n g u a g e competence t a k e s . A c q u i s i t i o n canno t be a c c o u n -t e d f o r s o l e l y b y r e f e r e n c e t o t h e i n n a t e s t r u c t u r e o f LAD a c c o r d i n g to t h i s p o s i t i o n . The t e n a t i v e h y p o t h e s e s about s t r u c t u r e e v i d e n t i n t h e c h i l d ' s p e r f o r m a n c e a r e i n s t e a d c o n s i d e r e d t o be a j o i n t f u n c t i o n o f t h e c h i l d ' s m a t u r i n g c o g n i t i v e f u n c t i o n s and t h e r e g u l a r i t i e s t h a t e x i s t i n t h e i n p u t . The t h r e e b a s i c p o s t u l a t e s t a k e n t o g e t h e r r e p r e s e n t a s t a r t i n g p o i n t f o r deve lopment o f a mode l l anguage a c q u i s i t i o n . But t h e mode l i s i n c o m -p l e t e , l i k e a compute r w i t h o u t a p r o g r a m . The o p e r a t i o n s by w h i c h t h e components make u s e o f p r i m a r y l i n g u i s t i c d a t a t o a r r i v e a t a s e t o f r u l e s have n o t been s p e c i f i e d . L i k e w i s e , t h e o p e r a t i o n s b y w h i c h t h e components make u s e o f t h e a c q u i r e d r u l e s so a s t o comprehend and p r o d u c e s e n t e n c e s a r e unknown. S p e c i f i c a t i o n o f a s e t o f o p e r a t i o n s c a n be f ound o n l y t h r o u g h e m p i r i c a l r e s e a r c h . Even t e n t a t i v e answers t o s u c h p rob l ems a r e as y e t a d i s t a n t g o a l . The v a l i d i t y o f t he b a s i c p o s t u l a t e s has n o t e ven been a d e q u a t e l y t e s t e d . In t h e n e x t s e c t i o n d a t a d e r i v e d f r om o r r e f l e c t -i n g upon t h e t h r e e p o s t u l a t e s i s r e v i e w e d . Language A c q u i s i t i o n R e s e a r c h G r a m m a t i c a l C l a s s e s and P h r a s e - S t r u c t u r e R u l e s . Many d i f f i c u l t i e s have been e n c o u n t e r e d i n d e v i s i n g t e c h n i q u e s t h a t wou ld p r o v i d e t h e d a t a needed t o answer q u e s t i o n s abou t t he c h i l d ' s a c q u i s i t i o n o f l i n g u i s t i c compe tence . In d i s c o v e r i n g t h e r u l e s o f grammar, l i n g u i s t s g e n e r a l l y r e l y on t h e i r own i n t u i t i o n and t h e i n t u i t i o n s o f o t h e r s p e a k e r s t o t e s t t h e h y p o t h e s e s made o n t h e b a s i s o f a c t u a l s p e e c h s a m p l e s . S i n c e t h e c h i l d ' s grammar c a n n o t be assumed t o be a s m a l l - s c a l e r e p l i c a o f t h e a d u l t ' s , t h e i n t u i t i o n o f the grammar w r i t e r c anno t be u s e d i n d i s c o v e r i n g t h e c h i l d ' s grammar (Brown & B e l l u g i , 1964). Even more c o n s t r a i n i n g i s t h e f a c t t h a t no one has been s u c c e s s f u l i n t a p p i n g t h e i n t u i t i o n s o f t h e c h i l d 13 f o r whom t h e grammar i s b e i n g w r i t t e n . L a c k i n g o t h e r s o u r c e s o f i n f o r m a t i o n , t h e i n v e s t i g a t i o n o f e a r l y l i n g u i s t i c competence has b e e n r e s t r i c t e d t o t h e a n a l y s i s o f samp les o f spon t aneous s p e e c h . T h r e e r e s e a r c h e r s have c o l l e c t e d samp les o f t h e e a r l y s p e e c h o f c h i l d r e n r a n g i n g f r om 18 months t o 36 m o n t h s : Brown and h i s a s s o c i a t e s (Brown 4 B e l l u g l , 1 9 6 4 ; Brown & F r a s e r , 1 9 6 3 ; B rown, F r a s e r & B e l l u g i , 1 9 6 4 ) , M i l l e r and E r v i n ( 1 9 6 4 ) , and B r a l n e ( 1 9 6 3 ) . The p r o c e -d u r e o f a n a l y s i s has been t o w r i t e a f o r m a l d e s c r i p t i o n o f grammar f o r e a c h c h i l d t h a t wou ld a c c o u n t f o r a l l o f t h e p r o d u c t i o n s l n h i s s p e e c h s a m p l e . I n one c a s e t h e a b i l i t y o f t h e c h i l d t o p r e d i c t a l a t e r samp le o f u t t e r a n c e s p r o d u c e d by t h e c h i l d was t e s t e d w i t h c o n s i d e r a b l e s u c c e s s (Brown, F r a s e r & B e l l u g l , 1 9 6 4 ) . Two s t e p s were i n v o l v e d i n w r i t i n g a grammar f o r t h e c h i l d ' s two-word u t t e r a n c e s : D e t e r m i n i n g (a) t h e c h i l d ' s word c l a s s e s and (b) t h e r u l e s g o v e r n i n g t h e s e q u e n c i n g o f t h e c l a s s e s . The s h a r e d c o n t e x t method o f a n a l y s i s was u s e d when p o s s i b l e t o d e t e r m i n e what words b e l o n g e d t o t h e same c l a s s . I f words were f o u n d to have I d e n t i c a l p r i v i l e g e s o f o c c u r r e n c e o r s h a r e d c o n t e x t s , i t was h y p o t h e s i z e d t h a t t h e y b e l o n g e d t o t h e same c l a s s . F o r examp l e , Brown and F r a s e r (1964) t a b l e d t h e t o t a l c o n t e x t s o f t h e words h e r e , t h e r e , Mum, and Dad f o r one o f t h e i r s u b j e c t s , Adam. They f o u n d t h a t h e r e and t h e r e s h a r e d 42% o f t h e t o t a l c o n t e x t s i n w h i c h t h e s e words were f o u n d . Mum and Dad s h a r e d 3 8 % , b u t n e i t h e r h e r e n o r t h e r e s h a r e d any c o n t e x t s w i t h Mum o r D a d . T h i s p a t t e r n o f d i s t r i b u t i o n i n d i -c a t e d t h a t h e r e and t h e r e b e l o n g e d to one c l a s s and Mum and Dad t o a s e p -a r a t e c l a s s , Some o f t h e c o n t e x t s s h a r e d by Mum and Dad and by h e r e and t h e r e w h i c h were u s e d as e v i d e n c e f o r t h e d i s t i n c t i o n I n c l u d e : 14 Want c o f f e e , Mum. H i , Mum. S e e , Mum. Want c o f f e e , D a d . H i , D a d . S e e , D a d . T h e r e g o e s . T h e r e i s . R i g h t t h e r e . T h e r e i t g o e s . He re goes He re i s . R i g h t h e r e . He re i t g o e s . G e n e r a l l y t h e r e s u l t s o f t h e Brown, E r v i n and B r a i n e s t u d i e s were i n agreement abou t t h e k i n d s o f c l a s s e s and r u l e s e v i d e n t i n t h e c h i l d ' s s p e e c h . E a r l y two-word u t t e r a n c e s were f o u n d t o f o l l o w a s i m i l a r p a t t e r n i n a l l s t u d i e s . These u t t e r a n c e s were composed o f a word b e l o n g i n g t o a c l a s s w i t h v e r y few members and a word b e l o n g i n g t o a much l a r g e r c l a s s . C l a s s membersh ip was i n f e r r e d o n t h e b a s i s o f d i s t r i b u t i o n a l e v i d e n c e as I l l u s t r a t e d i n t h e p a r a g r a p h a b o v e . A d o p t i n g B r a i n e ' s t e r m i n o l o g y ( 1 9 6 3 ) , t h e c l a s s c o n s i s t i n g o f few members i s c a l l e d t h e p i v o t c l a s s ( P ) . The l a r g e r c l a s s i s c a l l e d t h e o p e n c l a s s ( 0 ) . The p i v o t c l a s s was o b s e r v e d t o b e s i m i l a r t o a d u l t f u n c t i o n words i n two r e s p e c t s : The p i v o t c l a s s c o n s i s t e d o f few members and changed s l o w l y . However , t h e c h i l d ' s p i v o t c l a s s c o n t a i n e d words t h a t wou ld n o t be c l a s s i f i e d a s f u n c t i o n words i n a d u l t grammar. The p i v o t c l a s s was more c o m p r e h e n s i v e , i n c l u d i n g a d j e c -t i v e s and v e r b s a s w e l l a s a r t i c l e s and d e m o n s t r a t i v e a d j e c t i v e s . A p i v o t c l a s s was f o u n d i n e v e r y c h i l d ' s s p e e c h b u t t h e words b e l o n g i n g t o t h e c l a s s were d i f f e r e n t f o r each c h i l d . The o p e n c l a s s c o n s i s t e d p r i -m a r i l y o f nouns b u t i n c l u d e d some a d j e c t i v e s and v e r b s . The o r d e r o f t h e p i v o t and open c l a s s words i n u t t e r a n c e s was f o u n d t o be r e l a t i v e l y f i x e d . The s e q u e n c i n g r u l e w h i c h has been w r i t t e n t o c o v e r most o f t h e c h i l d ' s two-word u t t e r a n c e s i n t h e s e s t u d i e s i s r e p r e -s e n t e d a s f o l l o w s ( f r om M c N e i l l , 1 9 6 6 ) . S > (P) + 0 ( e . g . , my_ c o a t ) The p a r e n t h e s e s i n d i c a t e t h a t t he p i v o t word i s o p t i o n a l , t h a t t h e 15 p o s i b l l i t y o f o p e n - c l a s s words o c c u r i n g a l o n e e x i s t s . Not a l l o f t h e c h i l d r e n ' s u t t e r a n c e s were c o v e r e d by t h i s one r u l e even a t t h e e a r l i e s t p o i n t . Two a d d i t i o n a l r u l e s were r e q u i r e d t o c o v e r t h e s e u t t e r a n c e s : S > 0 + (P) ( e . g . , swea te r o f f ) S — > 0 + 0 ( e . g . , Adam c o a t ) I n s p e c t i o n o f t he r e c o r d s r e v e a l e d t h a t each c h i l d p r o d u c e d s e n t e n c e s w h i c h f i t one o f two ma in p a t t e r n s , (P) + 0 , o r 0 + ( P ) , and r a r e l y p r o -duced u t t e r a n c e s w h i c h f i t t h e o t h e r p a t t e r n . F o r most o f t h e c h i l d r e n t h e (P) + 0 p a t t e r n p r e d o m i n a t e d . One o f M i l l e r and E r v i n ' s s u b j e c t s , howeve r , p r o d u c e d u t t e r a n c e s w h i c h f i t t h e 0 + (P) p a t t e r n a l m o s t e n t i r e l y . The 0 + 0 p a t t e r n was f o u n d i n s e v e r a l o f t h e c h i l d r e n ' s r e c o r d s b u t r e p r e -s e n t e d a v e r y s m a l l p e r c e n t a g e o f t h e t o t a l u t t e r a n c e s . D u r i n g t h e n e x t p e r i o d o f d e v e l o p m e n t , c o n s i d e r a b l e change was f ound i n t h e word c l a s s e s b u t c o m p a r a t i v e l y l i t t l e change i n t h e b a s i c s e q u e n c -i n g r u l e s ( M c N e i l l , 1 9 6 6 ) . The deve lopment o f c l a s s e s was o b s e r v e d t o p r o c e e d a c c o r d i n g t o t h e most g e n e r a l law o f c o g n i t i v e d e v e l o p m e n t , d i f f e r -e n t i a t i o n (Werner , 1 9 4 8 ) . The b r o a d word c l a s s e s w h i c h had b e e n fo rmed by t h e two y e a r o l d were no t u n l i k e t h e k i n d s o f g r o u p i n g s made f o r non-l i n g u i s t i c s e n s o r y d a t a a t t h e age (Werner , 1948 j P l a g e t , 1 9 5 2 : v y g o t s k y , 1 9 6 2 ) . F o l l o w i n g L e n n e b e r g , I t m i g h t be s u g g e s t e d t h a t t he l e v e l o f m a t u r a t i o n o f c o g n i t i v e f u n c t i o n s a t t h a t age Imposed c o n s t r a i n t s on t h e f o rm t h a t e a r l y l i n g u i s t i c and n o n l i n g u i s t i c c l a s s e s c o u l d t a k e . As t h e c o n s t r a i n t s d e c r e a s e w i t h f u r t h e r m a t u r a t i o n and c o g n i t i v e d e v e l o p m e n t , d i f f e r e n t i a t i o n o f t h e p r i m i t i v e c l a s s e s s h o u l d t a k e p l a c e . A c c o r d i n g l y , t h e p i v o t c l a s s was o b s e r v e d to undergo s u c c e s s i v e s u b d i v i s i o n s , each s u b c l a s s h a v i n g d i s t i n c t p r i v e l e g e s o f o c c u r r e n c e . D i f f e r e n t i a t i o n o f t h e p i v o t c l a s s f o r one o f Brown and B e l l u g l ' s 16 s u b j e c t s was t r a c e d i n some d e t a i l b y M c N e i l l ( 1966 ) . P r o g r e s s was c h a r t e d a t t h r e e t ime p e r i o d s d u r i n g a f i v e month s p a n . When t h e c h i l d was f i r s t o b s e r v e d , a r t i c l e s , d e m o n s t r a t i v e p r o n o u n s , d e s c r i p t i v e a d j e c t i v e s , p o s s e s -s i v e p ronouns and q u a n t i f i e r s were a l l members o f one p i v o t c l a s s (p^ ) . As f a r as i t was p o s s i b l e t o d i s c e r n any o f t h e s e P^ words c o u l d be u s e d w i t h any o f t h e open c l a s s w o r d s . A t t ime P e r i o d 2 a r t i c l e s and demon-s t r a t i v e p ronouns were b e i n g u s e d i n c o n t e x t s no t s h a r e d by o t h e r p i v o t w o r d s . On t h e b a s i s o f t h i s e v i d e n c e o f d i s t i n c t i v e p r i v i l e g e s o f o c c u r -r e n c e , i t was h y p o t h e s i z e d t h a t d e m o n s t r a t i v e p ronouns ( t h a t , t h i s ) and a r t i c l e s ( a , t h e ) b e l o n g e d t o s e p a r a t e g r a m m a t i c a l c l a s s e s . F u r t h e r d i f -f e r e n t i a t i o n o f P^ was e v i d e n t a t T ime 3. A r t i c l e s , d e m o n s t r a t i v e p r o -n o u n s , p o s s e s s i v e p r o n o u n s , a d j e c t i v e s and q u a n t i f i e r s were a l l f o u n d t o have d e f i n i t e p r i v i l e g e s o f o c c u r r e n c e . I n t h e p r e c e d i n g d i s c u s s i o n i t has been assumed t h a t d i s t i n c t p a t t e r n s i n t h e c h i l d ' s s p e e c h r e f l e c t h i s compe tence . However , i t s h o u l d be made e x p l i c i t t h a t t h e f o r m a l d e s c r i p t i o n s o f t h e c h i l d ' s word c l a s s e s and s e q u e n c i n g r u l e s o n l y r e p r e s e n t h y p o t h e s e s abou t t h e c h i l d ' s c o m p e t e n c e . I t i s e n t i r e l y p o s s i b l e t h a t a r e p r e s e n t a t i o n may f a l s e l y a t t r i b u t e l i n -g u i s t i c knowledge o r may be u n d e r e s t i m a t i n e : t h e c h i l d ' s compe tence . The l a t t e r p o s s i b i l i t y i s a lways g r e a t when t h e r e p r e s e n t a t i o n s a r e based s o l e l y on s p e e c h . Comprehens ion d a t a m igh t y i e l d i n a v e r y d i f f e r e n t mode l o f t he c h i l d ' s compe tence , p a r t i c u l a r l y s i n c e i t i s g e n e r a l l y a c -c e p t e d t h a t comprehens i on p r e c e d e s p r o d u c t i o n ( F r a s e r , B e l l u g i & Brown, 1963j M c N e i l l , 1 9 6 8 ) . I t i s p r o b a b l y t h e c a s e t h a t competence I s a c t u a l l y more advanced t h a n i n f e r r e d f r om p r o d u c t i o n . The c o n c l u s i o n t h a t t h e p i v o t v e r s u s open c l a s s d i s t i n c t i o n and t h e S i m p l e (P) + 0 s e q u e n c i n g r u l e r e f l e c t t h e c h i l d ' s e a r l y competence i s b a s e d o n two arguments ( M c N e i l l , 1 9 6 6 ) . F i r s t , t h e s h e e r number o f 17 d i f f e r e n t c o m b i n a t i o n s o f words i n t he r e p e r t o i r e o f a two y e a r o l d i s somewhat u n b e l i e v a b l e i f one assumes t h e y r e p r e s e n t memor ized c o m b i n a t i o n s f r om a d u l t s p e e c h . I t i s more p l a u s i b l e (and p a r s i m o n i o u s ) t o p o s t u l a t e t h a t t h e c h i l d h a s a c q u i r e d a few s i m p l e r u l e s . S e c o n d , i n e v e r y c h i l d ' s s p e e c h sample t h e r e e x i s t s a s e t o f u t t e r a n c e s w h i c h s i m p l y c o u l d n o t be i m i t a t i o n s o f an a d u l t m o d e l . T h e s e u t t e r a n c e s , howeve r , a r e c o n s i s t e n t w i t h t h e r u l e s h y p o t h e s i z e d t o r e p r e s e n t t he c h i l d ' s l i n g u i s t i c competence (See B rown , F r a s e r & B e l l u g l , 1 9 6 4 ) . In summary, t h e e a r l y s p e e c h o f c h i l d r e n c a n be b e s t c h a r a c t e r i z e d a s r u l e - g o v e r n e d , a l t h o u g h I t i s d i f f i -c u l t to d e t e r m i n e t h e a c t u a l r u l e t h a t has been a b s t r a c t e d by t h e c h i l d . T h e o r e t i c a l C o n s i d e r a t i o n s . A n i n t e r e s t i n g r e l a t i o n s h i p between t h e c h i l d ' s e a r l y h y p o t h e s i z e d competence and t h e f o r m a l grammar w r i t t e n by Chomsky has b e e n p o i n t e d o u t b y M c N e i l l ( 1 9 6 6 ) . R e i t e r a t i n g , t h e grammar i n c l u d e s a b a s e component w h i c h d e f i n e s a l l t h e g r a m m a t i c a l r e l a t i o n s r e q u i r e d f o r s e m a t i c i n t e r p r e t a t i o n and a t r a n s f o r m a t i o n a l component w h i c h a s s i g n s a s u r f a c e s t r u c t u r e t o t h e b a s e s t r i n g . The c h i l d ' s e a r l y competence as I n f e r r e d f rom s p e e c h samp les was f o u n d t o i n c l u d e r u d i m e n -t a r y knowledge o f c l a s s e s , h i e r a r c h i c a l r u l e s and g r a m m a t i c a l r e l a t i o n s , a l l o f wh i ch a r e a s p e c t s o f t h e b a s e component . C o r r e s p o n d e n c e between t h e g rowth o f s t r u c t u r a l knowledge and d e r i v a t i o n m i g h t w e l l be i n t e r -p r e t e d as e v i d e n c e t h a t t h e g e n e r a t i v e grammar mode l p r o p o s e d b y Chomsky i s a good r e p r e s e n t a t i o n o f t h e o p e r a t i o n s t h e c h i l d i s a c t u a l l y p e r f o r m -i n g . To t h e e x t e n t t h a t i t i s a good r e p r e s e n t a t i o n , t h e c h i l d ' s e a r l y s p e e c h may be c h a r a c t e r i z e d a s a d i r e c t p h o n o l o g i c a l i n t e r p r e t a t i o n o f unmarked b a s e s t r u c t u r e s . I n agreement w i t h t h i s p o s i t i o n M c N e i l l (1966) has s u g g e s t e d t h a t " c h i l d r e n . . . b e g i n t h e i r g r a m m a t i c a l c a r e e r s w i t h t h e p a r t o f s y n t a x t h a t i s n e c e s s a r y t o s e m a n t i c i n t e r p r e t a t i o n and o n l y l a t e r a t t a c h t h e g r a m m a t i c a l m a c h i n e r y t h a t i n matu re grammar p r o v i d e s i n p u t t o p h o n o l o g i c a l i n t e r p r e t a t i o n . " T h i s v i e w has c o n s i d e r a b l e s i g n i f i c a n c e r e g a r d i n g t h e k i n d o f h y p o -t h e s e s one fo rms t o a c c o u n t f o r how t h e c h i l d a c q u i r e s l a n g u a g e . The e v i -dence s u g g e s t i n g t h a t t h e c h i l d ' s e a r l y s p e e c h r e f l e c t s t h e deep s t r u c -t u r e o f l a n g u a g e r a t h e r t h a n t h e d i r e c t l y e x p e r i e n c e d s u r f a c e s t r u c t u r e . must b e a c c o u n t e d f o r . M c N e i l l m a i n t a i n s t h a t any t h e o r y w h i c h empha-s i z e s t h e o b s e r v a b l e c h a r a c t e r i s t i c o f a d u l t s p e e c h c o u l d n e v e r a c c o u n t f o r t h e c h i l d ' s e a r l y s p e e c h p a t t e r n s . The n e x t t h e o r e t i c a l s t e p , how-e v e r , i s a l a r g e o n e . M c N e i l l a r g u e s t h a t t h e c h i l d i s a b l e t o a r r i v e a t t h e b a s e s t r u c t u r e r a t h e r t h a n s u r f a c e s t r u c t u r e b e c a u s e i n n a t e know-l e d g e o f l a n g u a g e g u i d e s t h e i n d u c t i o n s made f r o m t h e i n p u t . The i n n a t e knowledge a t t r i b u t e d t o t h e c h i l d a r e t h e l i n g u i s t i c u n i v e r s a l s , b o t h s u b s t a n t i v e and f o r m a l . W i t h t h i s i n n a t e knowledge l a n g u a g e a c q u i s i t i o n becomes a m a t t e r o f m a t c h i n g t h e a d u l t s p e e c h t o t h e i n n a t e s t r u c t u r e , p e r h a p s , t e m p l a t e m a t c h i n g . M c N e i l l i s n o t c l e a r abou t how t h i s f o r m o f i n d u c t i o n m i g h t t a k e p l a c e , b u t does m i n i m i z e t h e i m p o r t a n c e o f d i s t r i -b u t i o n a l e v i d e n c e i n t h e a d u l t ' s s p e e c h . A more mode ra te p o s i t i o n has been t a k e n by F o d o r ( 1 9 6 6 ) . He m a i n -t a i n s t h a t i t i s n o t i n c o n s i s t e n t t o p r o p o s e t h a t a d e v i c e w i t h i n t r i n s i c l i n g u i s t i c knowledge makes u s e o f d i s t r i b u t i o n a l e v i d e n c e i n t h e p r i m a r y l i n g u i s t i c i n p u t t o a r r i v e a t b a s e s t r u c t u r e . He s t a t e s : I t i s , however , u n r e a s o n a b l e t o deny a p r i o r i t h a t i n l e a r n i n g h i s l a n g u a g e t h e c h i l d may t a k e a d v a n t a g e o f d i s t r i b u t i o n a l r e g u l a r i t i e s i n h i s c o r p u s . Such r e g u l a r i t i e s wou ld b e good g u i d e s t o t h e t e n t a t i v e a n a l y s i s o f t h e c o r p u s i n t o c l a s s e s , and i t i s p r e c i s e l y such t e n t a t i v e a n a l y s e s t h a t a r e r e q u i r e d i f h e i s t o employ r u l e s t h a t p r o j e c t p u t a t i v e d e s c r i p t i o n s o f u n d e r -l y i n g s t r u c t u r e ( i b i d . , p . 1 1 8 ) . A c c o r d i n g t o F o d o r , t h e c h i l d a r r i v e s a t a n h y p o t h e s i s a b o u t t h e c l a s s e s and r u l e s o f t h e b a s e component o n t h e b a s i s o f i n f o r m a t i o n e x t r a c t e d f r o m p r i m a r y l i n g u i s t i c d a t a . C o n t r a r y t o M c N e i l l , F o d o r 19 assumes t h a t what t h e c h i l d b r i n g s t o t h e t a s k o f i n d u c t i o n i s n o t i n n a t e knowledge o f t h e c l a s s e s and r u l e s b u t s i m p l y an i n t r i n s i c c o g n i t i v e c a p -a c i t y t o o r g a n i z e s e n s o r y i n p u t a c c o r d i n g t o r e g u l a r i t i e s a b s t r a c t e d f r o m t h e t o t a l c o n f i g u r a t i o n . The r e s u l t s o f t h e e a r l y o r g a n i z a t i o n r e p r e s e n t t h e c h i l d ' s i m p l i c i t knowledge o f t h e s t r u c t u r e o f s e n t e n c e s . The u n d i f f e r e n t i a t e d n a t u r e o f t h i s e a r l y knowledge r e s u l t s i n t h e p r o -d u c t i o n o f many u t t e r a n c e s t h a t a r e t o t a l l y i n c o n s i s t e n t w i t h t h e a d u l t l a n g u a g e u s e r ' s i m p l i c i t knowledge o f s t r u c t u r e . Knowledge a b o u t t h e s t r u c t u r e o f l a n g u a g e c a n be m o d i f i e d , t h o u g h , i n t h e f a c t o f c o n t r a d i c -t o r y e v i d e n c e , and t h a t i s what o c c u r s . As s p e e c h p a t t e r n s i n c o n s i s t e n t w i t h t h e c h i l d ' s c u r r e n t knowledge a r e e n c o u n t e r e d , t h e i m p l i c i t r u l e s undergo r e f o r m u l a t i o n . The new f o r m u l a t i o n i s l i k e l y t o be i n c o r r e c t — i n c o r r e c t i n t h a t i t i s t oo comprehens i v e and r e s u l t s i n u t t e r a n c e s n o t admis8able i n t h e a d u l t l a n g u a g e . A c c o r d i n g t o F o d o r , deve lopment o f l i n g u i s t i c competence may be c h a r a c t e r i z e d as a c o n t i n u i n g p r o c e s s o f i m p l i c i t r u l e f o r m a t i o n and r e f o r m u l a t i o n . S i n g l e - B a s e T r a n s f o r m a t i o n s . The t a s k o f a c q u i s i t i o n c anno t be c o n s i d e r e d c o m p l e t e when the b a s e s t r u c t u r e r u l e s have been a t t r i b u t e d t o t h e c h i l d . A d u l t s do n o t speak i n b a s e s t r u c t u r e s b u t g i v e p h o n o l o g i -c a l i n t e r p e t a t i o n t o s u r f a c e s t r u c t u r e . The c o n v e r s i o n o f b a s e s t r u c t u r e i n t o s u r f a c e s t r u c t u r e r e q u i r e s knowledge o f a new t y p e o f r u l e a c c o r d i n g t o t h e t r a n s f o r m a t i o n m o d e l , n a m e l y , t h e t r a n s f o r m a t i o n . L i t t l e i s known about t h e a c q u i s i t i o n o f t r a n s f o r m a t i o n s . I t has o n l y been i n r e c e n t y e a r s t h a t r e p o r t s o f t h e deve lopment o f t h e s e r u l e s have been p u b l i s h e d . Some o f t h e s e r e p o r t s a r e b a s e d o n c o n t i n u a t i o n s o f t h e o b s e r v a t i o n s o f t h e c h i l d r e n i n t h e Brown p r o j e c t p r e v i o u s l y d i s -c u s s e d . The d a t a a v a i l a b l e a t p r e s e n t a r e l i m i t e d t o two s i n g l e - b a s e t r a n s f o r m a t i o n s , t h e n e g a t i v e ( B e l l u g i , 1964) and t h e q u e s t i o n ( B e l l u g i , 20 1965; Brown, 1968). In the Bellugl study, the growth of the negative transformation was found to follow a similar pattern for a l l the children observed although the patterns were evident at different ages. Time periods rather than specific ages were therefore used to Indicate successive stages of rule differentiation. The f i r s t Instances of the negative morpheme in the child's utter-ances (Period 1) were considered, by Bellugl to represent a "tacking on" of the negative morpheme to the base structure (e.g., NEG + Pred P or NEC -I- NP). Examples of utterances produced In this way include, no wipe  finger, not f i t and no singing song. In the following period, Period 2, the children continued to prefix base structures with the negative but also produced the negative i n com-bination with the auxiliary (e.g., I can't see you). The auxiliaries were not found i n the children's speech apart from the use with the nega-tive indicating that these Instances of the negative probably represented vocabulary items. Such Instances could not be taken as evidence of pro-ductive transformation rules i n the child's competence. By Period 3 sentences of the I n i t i a l no Rusty hat form had disap-peared. The negative was used In the adult form, e.g., I can't see i t ; L 3£ not & doctor; that not turning. Since the auxiliary appeared in utterances which did not carry the negative morpheme as well as in utter-ances which did carry the negative morpheme, i t was hypothesized that the child must be transforming base structure to produce the surface utter-ance. Use of the obligatory do transformation was also attributed to the children. The auxiliary do was introduced appropriately when no auxiliary was generated by the base component to carry the negative. The fact that the negative occurred with other auxiliaries besides do 21 was t a k e n a s e v i d e n c e t h a t d o n ' t was n o t s i m p l y a v o c a b u l a r y i t e m . No new r u l e s were e v i d e n t i n P e r i o d 4 b u t r e f i n e m e n t o f t h e new ly a c q u i r e d t r a n s f o r m a t i o n r u l e s was c o n t i n u e d . I f i t i s assumed t h a t t h e d e v e l o p m e n t a l s equence o f a l l s i n g l e -b a s e t r a n s f o r m s f o l l o w s a s i m i l a r c o u r s e , t h e q u e s t i o n t r a n s f o r m wou ld be e x p e c t e d t o d e v e l o p i n an a n a l o g o u s f a s h i o n . 1. Base s t r u c t u r e p l u s r i s i n g i n f l e c t i o n p a t t e r n ( e . g . , B a l l go? ) 2. I n t e r o g a t i v e I n t r o d u c e d as v o c a b u l a r y i t e m ( e . g . , What t h a t ? ; What? ; Why?) 3. Base s t r u c t u r e p r e f i x e d w i t h i n t e r r o g a t i v e p ronoun w i t h no change i n t h e o r d e r o f t h e a u x i l i a r y o r s u b j e c t o f t h e s e n -t e n c e ( e . g . , Why i t c a n ' t t u r n o f f ? ) The g row th o f t h e q u e s t i o n has been s t u d i e d by Brown (1968) i n t h e same two s u b j e c t s a s u s e d i n t h e B e l l u g i n e g a t i v e s t u d y p l u s one a d d i t i o n a l c h i l d . Brown d i d n o t p r e s e n t d a t a w h i c h wou ld a l l o w c o n f i r m a t i o n o f t h e h y p o t h e s i z e d e a r l y u s e o f i n f l e c t i o n b u t t h e d a t a d i d c o n f i r m t h e r e m a i n -d e r o f t h e s e q u e n c e o f g rowth a s h y p o t h e s i z e d h e r e . Bo th Brown and B e l l u g i ' s d a t a s u g g e s t t h a t the c h i l d a c q u i r e s r u l e s w h i c h c a n be r e p r e s e n t e d by t h e t r a n s f o r m a t i o n t y p e o f r u l e p r o p o s e d by Chomsky. The d e v e l o p m e n t a l p a t t e r n i s n o t c o n s i s t e n t w i t h t h e f o r m a l d e r i v a t i o n o f t h e s t r u c t u r e s , however . M c N e i l l ' s s u g g e s t i o n t h a t t h e t r a n s f o r m a t i o n a l grammar mode l may s e r v e a s a p r e d i c t i v e mode l o f s y n t a c -t i c deve lopment may have been p r e m a t u r e . Doub le-Base T r a n s f o r m a t i o n s . W i t h knowledge o f t h e s i n g l e - b a s e t r a n s f o r m a t i o n s a g r e a t v a r i e t y o f s e n t e n c e s can be u n d e r s t o o d and p r o -d u c e d . W i t h i n a r i c h l i n g u i s t i c e n v i r o n m e n t , however , s e n t e n c e s become l o n g e r and more complex s t r u c t u r a l l y ( c f . , M c C a r t h y , 1 9 5 4 ) . T h i s i n c r e a s -ed c o m p l e x i t y c a n e i t h e r be a c h i e v e d by c o m b i n i n g o l d p h r a s e - s t r u c t u r e and s i n g l e - b a s e t r a n s f o r m a t i o n r u l e s t o p r o d u c e s e n t e n c e s w i t h c o m p l i c a t e d 22 p r e p o s i t i o n a l p h r a s e s , n e g a t i v e - q u e s t i o n s , p a s s i v e - n e g a t i v e - q u e s t i o n s , and so o n , o r by c o m b i n i n g more than one b a s e s t r i n g . The f o r m e r t y p e o f c o m p l e x i t y c a n be a c h i e v e d w i t h o u t a c q u i r i n g new r u l e s , hence i t does n o t r e a l l y r e p r e s e n t a d d i t i o n a l g r a m m a t i c a l compe tence . The a d d i t i o n a l c o m p l e x i t y i s p r o b a b l y p o s s i b l e b e c a u s e o f g rowth o f t he c h i l d ' s memory s p a n . The l a t t e r t y p e o f c o m p l e x i t y , a c h i e v e d b y comb in i ng two o r more b a s e s t r i n g s , r e q u i r e s knowledge o f a new s e t o f r u l e s , d o u b l e - b a s e t r a n s f o r m a t i o n r u l e s . S t r u c t u r e s w h i c h have a d o u b l e - b a s e t r a n s f o r m a t i o n a l h i s t o r y do r e p r e s e n t t he ach i evement o f g r e a t e r c o m p l e x i t y by t h e a p p l i c a t i o n o f new r u l e s and a r e t h e r e f o r e o f p r i m a r y i n t e r e s t . The a d d i t i o n o f t h e d o u b l e - b a s e t y p e o f t r a n s f o r m a t i o n r u l e t o t h e c h i l d ' s l i n g u i s t i c compe-t e n c e has r e c e i v e d d i s p r o p o r t i o n a t e l y l i t t l e a t t e n t i o n . The o n l y e x t e n s i v e s t u d i e s o f t he c h i l d ' s knowledge o f d o u b l e - b a s e t r a n s f o r m a t i o n r u l e s a r e by Henyuk (1963a , 1964 , 1 9 6 9 ) . D a t a i n t h e s e c r o s s - s e c t i o n a l s t u d i e s were c o l l e c t e d by r e c o r d i n g s p e e c h e l i c i t e d i n t h r e e s t i m u l u s c o n d i t i o n s : (1) p r o j e c t i v e B l a c k y P i c t u r e s , (2) c o n v e r -s a t i o n w i t h an a d u l t , and (3) r o l e p l a y i n g i n a f a m i l y s i t u a t i o n w i t h p e e r s . The s u b j e c t s were n u r s e r y s c h o o l , k i n d e r g a r t e n and f i r s t g r ade c h i l d r e n r a n g i n g f r om 2 y e a r s , 10 mon ths , t o 7 y e a r s , 1 month . The p u r p o s e o f the t h r e e e a r l y s t u d i e s was t o d e t e r m i n e t o what e x t e n t t he s e n t e n c e s p r o d u c e d by t h e s e c h i l d r e n c o u l d be d e s c r i b e d by a t r a n s f o r m a -t i o n a l grammar. The p r o c e d u r e o f a n a l y s i s employed by Menyuk was e s s e n -t i a l l y a t a b u l a t i o n o f t h e number o f c h i l d r e n o f each a g e - g r o u p i n g u s i n g each o f a c a t a l o g o f t r a n s f o r m a t i o n s , s i n g l e - and d o u b l e - b a s e . Forms wh i ch the t r a n s f o r m a t i o n mode l d i d n o t c o v e r were c a t e g o r i z e d a s o m i s s i o n s , r e d u n d a n c i e s o r s u b s t i t u t i o n s . The g l o b a b i l i t y o f the e a r l y s t u d i e s a l l o w e d p r i m a r i l y f o r t h e c o n c l u s i o n t h a t the u s e o f s t r u c t u r e s w h i c h 23 may r e p r e s e n t knowledge o f t r a n s f o r m a t i o n r u l e s i n c r e a s e d w i t h a g e . I n h e r 1969 monograph, Menyuk was c o n c e r n e d w i t h e x t r a c t i n g e v i d e n c e about t h e sequence o f deve lopment o f t r a n s f o r m a t i o n s and i n i d e n t i f y i n g t h e s equence o f a p p r o x i m a t i o n s t o t h e a d u l t fo rms f o r p a r t i c u l a r t r a n s -f o r m a t i o n s . She i d e n t i f i e d s e v e r a l o p e r a t i o n s used by c h i l d r e n i n c o n -s t r u c t i n g u t t e r a n c e s . The sequence i n wh i ch t h e s e o p e r a t i o n s were used by c h i l d r e n o f i n c r e a s i n g ages was : a d d i t i o n , d e l e t i o n , s u b s t i t u t i o n , p e r m u t a t i o n , n e s t i n g and embedd ing . Some o f t h e s e o p e r a t i o n s s u c h as embedding and n e s t i n g o n l y a p p l y t o d o u b l e - b a s e t r a n s f o r m a t i o n , hence l a t e r a p p e a r a n c e wou ld be e x p e c t e d . Menyuk a r g u e d t h a t i t may be more f r u i t f u l t o a n a l y z e t h e c h i l d ' s speech i n terms o f the g r a m m a t i c a l o p e r -a t i o n s h e can p e r f o r m , e . g . , a d d i t i o n , t han i n t e rms o f s u c c e s s i v e s t e p s i n t h e f o r m a l d e r i v a t i o n o f t h e Tjell-formed s t r u c t u r e . Tha t i s , a d i s -t i n c t i o n must be made between the k i n d o f r u l e and t h e o p e r a t i o n s i n v o l -v e d i n u t i l i z a t i o n o f a r u l e . The n e c e s s i t y o f mak ing t h i s d i s t i n c t i o n has been p r e v i o u s l y made e x p l i c i t b y Chomsky (1965) b u t l a r g e l y i g n o r e d . I t w i l l b e r e c a l l e d t h a t M c N e i l l i n t e r p r e t e d t h e c o r r e s p o n d e n c e between the growth o f s t r u c t u r a l knowledge o f p h r a s e - s t r u c t u r e r u l e s and t h e d e r i v a t i o n o f t he r u l e s a s e v i d e n c e t h a t the Chomsky g e n e r a t i v e g r a m -mar was a good r e p r e s e n t a t i o n o f t he o p e r a t i o n s the c h i l d a c t u a l l y l e a r n s . Because the r e s u l t s o f a n a l y s i s o f e a r l y speech p a r a l l e l e d the f o r m a l s t r u c t u r a l d e r i v a t i o n , t h e r e was no need t o make a d i s t i n c t i o n between r u l e and o p e r a t i o n . T h e r e i s , however , l i t t l e e v i d e n c e t h a t the c o r r e s p o n d e n c e f o u n d a t t h e p h r a s e - s t r u c t u r e l e v e l h o l d s t r u e f o r t r a n s f o r m a t i o n a l s t r u c t u r e s . The t r a n s f o r m a t i o n a l grammar may be an adequa te r e p r e s e n t a t i o n o f what t h e c h i l d u l t i m a t e l y knows about l a n g u a g e , bu t i t cannot p r e d i c t t h e d e -v e l o p m e n t a l sequence and fo rm o f p a r t i c u l a r s t r u c t u r e s . R u l e s have been 24 i n f e r r e d f rom e a r l y speech t h a t have no r e a d i l y d i s c e m a b l e r e l a t i o n s h i p t o t he f o r m a l d e r i v a t i o n o f the t r a n s f o r m a t i o n s ( e . g . , s ee B e l l u g i , 1 9 6 4 ) . I t may be i m p o r t a n t f o r r e s e a r c h e r s and t h e o r e t i c i a n s t o overcome t h e t e n d e n c y t o a c c e p t the t r a n s f o r m a t i o n a l grammar as a mode l o f t he o p e r a -t i o n s the l a n g u a g e u s e r l e a r n s i f a mode l o f l anguage p e r f o r m a n c e i s t o b e f o r t h c o m i n g . The t r a n s f o r m a t i o n a l grammar may o n l y s e r v e as a f o r m a l r e p r e s e n t a t i o n o f t h e r u l e s a d u l t l a n g u a g e u s e r s u t i l i z e , n o t as a mode l o f t h e o p e r a t i o n s i n v o l v e d i n c o n s t r u c t i o n o f s e n t e n c e s by c h i l d r e n o r a d u l t s . The l a c k o f c o r r e s p o n d e n c e between t h e d e r i v a t i o n o f t r a n s f o r m a t i o n a l s t r u c t u r e s and the c h i l d ' s e a r l y r u l e s may be used i n s u p p o r t o f t he n o t i o n t h a t t h e c a p a c i t i e s o f t h e l anguage u s e r d e t e r m i n e t h e fo rm t h a t t h e r u l e s t r i l l t a k e ( c f . , Y n g v e , 1 9 6 0 ) . O n l y when the c h i l d i s c a p a b l e o f c e r t a i n o p e r a t i o n s w i l l t he f o rm o f h i s grammar c l o s e l y a p p r o x i m a t e t h e t r a n s f o r m a t i o n a l r u l e s a t t r i b u t e d t o the a d u l t . A b l o s s o m i n g o f s e e m i n g l y u n r e l a t e d s t r u c t u r e s s h o u l d o c c u r i n speech whenever a new o p e r a t i o n becomes a p a r t o f the c h i l d ' s c a p a b i l i t i e s . T h e r e i s some e v i d e n c e t h a t t h i s does o c c u r ( I lenyuk, 1969 ) . T h e r e a r e s e v e r a l app roaches t h a t r e s e a r c h e r s can t a k e i n an e f f o r t t o c l a r i f y the r e l a t i o n s h i p between t h e t r a n s f o r m a t i o n a l mode l and (1) t he sequence o f deve lopment o f f o r m a l l y r e l a t e d s t r u c t u r e s , (2) t he f o r m o f e a r l y r u l e s and (3) the o p e r a t i o n s i n v o l v e d i n p r o d u c t i o n and c o m p r e -h e n s i o n . One o f t h e s e a p p r o a c h e s i s t o i n t e n s i v e l y s t u d y the d e v e l o p -ment o f f o r m a l l y r e l a t e d s t r u c t u r e s , mak ing s p e c i f i c p r e d i c t i o n s abou t s equence o f deve lopment and t h e f o rm o f e a r l y r u l e s . T h i s a p p r o a c h was t a k e n i n t h e p r e s e n t s t u d y . 25 The Pu rpose o f t h e S tudy The p r e c e d i n g r e v i e w o f s y n t a c t i c a c q u i s i t i o n l i t e r a t u r e i n d i c a t e d t h a t t h e r e a r e many u n r e s o l v e d q u e s t i o n s . A l t h o u g h t h e e v i d e n c e s u g g e s t s t h a t young c h i l d r e n a r e a c q u i r i n g i m p l i c i t r u l e s about t h e s t r u c t u r e o f l a n g u a g e , s p e c i f i c a t i o n o f t h e f o r m a l n a t u r e o f t h e r u l e s has o n l y begun . A t p r e s e n t , t h e r e i s a l m o s t no d a t a wh i ch wou ld a l l o w f o r e x p l i c i t h y p o -t h e s e s about t h e c h i l d ' s knowledge o f complex s t r u c t u r e s s u c h a s t he n o m i n a l a d j e c t i v e o r a d j e c t i v a l r e l a t i v e c l a u s e . One o f t h e g o a l s o f t he s t u d y was t o g a t h e r d a t a wh i ch wou ld a l l o w f o r deve lopment o f s p e c i -f i c h y p o t h e s e s about t h e r u l e s r e p r e s e n t i n g t h e c h i l d ' s e a r l y knowledge o f t h e r e l a t i v e c l a u s e and a d j e c t i v e . The r e l a t i v e c l a u s e and a d j e c t i v e were s e l e c t e d f o r s t u d y p r i m a r i l y b e c a u s e so l i t t l e i s p r e s e n t l y known about t h e deve lopment o f s t r u c t u r e s t h a t a r e r e p r e s e n t e d a s d o u b l e - b a s e t r a n s f o r m a t i o n s . F u r t h e r m o r e , t h e r e l a t i v e c l a u s e and a d j e c t i v e a r e two ma jo r ways o f m o d i f y i n g t h e noun and i t has been f o u n d t h a t t h e ma jor g rowth i n l e n g t h and c o m p l e x i t y o f p r o d u c t i o n s i n c h i l d r e n o c c u r s i n t h e n o m i n a l ( H u n t , 1 9 6 5 ; Menyuk, 1 9 6 9 ) . A s e c o n d g o a l o f t h e s t u d y was t o t e s t s p e c i f i c p r e d i c t i o n s about t h e p s y c h o l o g i c a l d i f f i c u l t y and on togeny o f t h e a d j e c t i v a l r e l a t i v e c l a u s e and n o m i n a l a d j e c t i v e . I n t h e p r e c e d i n g r e v i e w o f t h e l i t e r a -t u r e , i t was n o t e d t h a t i n t h e few s t u d i e s t h a t have f o c u s e d o n s t r u c -t u r e s r e q u i r i n g more t h a n one t r a n s f o r m a t i o n , l i t t l e e v i d e n c e f o r c o r r e s -pondence between f o r m a l t r a n s f o r m a t i o n a l h i s t o r y and on togeny has been f o u n d . N e v e r t h e l e s s , a s t r o n g t endency p e r s i s t s i n t h e l i t e r a t u r e t o t r e a t t h e competence mode l as a p e r f o r m a n c e m o d e l . T h i s t e n d e n c y p r o b -a b l y s tems f r o m the l a c k o f d a t a and t h e absence o f an adequa t e p e r f o r -mance mode l f rom w h i c h t o d e r i v e m e a n i n g f u l h y p o t h e s e s . The a p p a r e n t u t i l i t y o f the t r a n s f o r m a t i o n a l grammar mode l i n 26 a c c o u n t i n g f o r t h e s t r u c t u r e o f t he c h i l d ' s e a r l y two word u t t e r a n c e s a l s o may have s e r v e d t o p e r p e t u a t e t h e hope t h a t t h e t r a n s f o r m a t i o n a l mode l c o u l d do d o u b l e - d u t y a s a competence and p e r f o r m a n c e m o d e l . A grammar mode l t h a t meets t h e c r i t e r i a s p e c i f i e d i n t h e g e n e r a l i n t r o d u c t i o n f o r an adequa te m o d e l , w i l l b e a b l e t o g e n e r a t e a n i n f i n i t e number o f g r a m m a t i c a l s e n t e n c e s and o n l y t h o s e t h a t a r e g r a m m a t i c a l . T h e r e i s no r e a s o n t o e x p e c t t h a t even i f t h e l anguage u s e r has a c q u i r e d s u c h a mode l t h a t he w i l l n o t make e r r o r s i n p e r f o r m a n c e o r t h a t he w i l l n e c e s s a r i l y p r o c e s s s e n t e n c e s i n a manner c o n s i s t e n t w i t h t h e f o r m a l d e r i v a t i o n . F o r examp le , a number o f s t u d i e s have shown t h a t t h e l a n g u -age u s e r c a n n o t u n d e r s t a n d a s e l f - embedded s e n t e n c e such as " T h e r a t t h a t t h e c a t t h a t t h e dog t h a t t h e cow t o s s e d w o r r i e d k i l l e d a t e t he m a l t . " He c a n , however , u n d e r s t a n d t h e s e n t e n c e " T h e r a t t h a t t h e c a t k i l l e d a t e t h e m a l t " even though t h e l a t t e r s e n t e n c e does n o t r e q u i r e any new s y n t a c t i c knowledge ( M i l l e r , 1962 ; M i l l e r & I s a r d , 1 9 6 4 ) . The grammar mode l p r o p o s e d by Chomsky may f o r m a l l y r e p r e s e n t t he knowledge a l anguage u s e r a c q u i r e s about h i s l a n g u a g e , b u t u n l e s s t h e u s e r has an i n f i n i t e s h o r t t e rm memory, he w i l l n o t be a b l e t o a c t u a l l y p roduce o r comprehend many o f t h e s e n t e n c e s t h a t c o u l d be g e n e r a t e d knowing what h e d o e s . Because o f t h e c o n s t r a i n t s o f memory on t h e l anguage u s e r ' s p e r f o r -mance a l o n e , a mode l o f competence such a s t h e t r a n s f o r m a t i o n a l grammar c o u l d h a r d l y b e e x p e c t e d t o a c c u r a t e l y p r e d i c t p e r f o r m a n c e o r s p e c i f y t h e p r o c e s s e s i n v o l v e d i n p r o d u c t i o n o r c o m p r e h e n s i o n . Y e t , d a t a a r e o f t e n m a t t e r o f f a c t l y d i s c u s s e d a s i f s u c h a c o r r e s p o n d e n c e h o l d s . I n a n a t t e m p t t o e v a l u a t e t h e adequacy o f t h e t r a n s f o r m a t i o n a l mode l a s a c o m b i n a t i o n competence-pe r fo rmance m o d e l , s p e c i f i c p r e d i c t i o n s were made a b o u t (1) t h e r e l a t i v e d i f f i c u l t y o f a d j e c t i v e , r e l a t i v e c l a u s e and 27 p a i r s o f s i m p l e s e n t e n c e s , and (2) t h e sequence o f emergence o f t h e s e same t y p e s o f s e n t e n c e s * W i t h t h e e x c e p t i o n o f B r a i n e ' s work ( 1 9 6 3 ) , t h e a c q u i s i t i o n r e s e a r c h h a s l a r g e l y stemmed f r om and been i n t e r p r e t e d i n terms o f t h e t r a n s f o r m a -t i o n a l m o d e l . T h e r e i s a t l e a s t one o t h e r m o d e l , more c l e a r l y a p e r f o r -mance m o d e l , t h a t h a s n o t y e t been a p p l i e d t o e a r l y s y n t a c t i c a c q u i s i t i o n . T h i s mode l p r o p o s e d b y Yngve ( 1960 ) , c o u n t e r s one o f t he p o s t u l a t e s (2) d i s c u s s e d i n t h e g e n e r a l i n t r o d u c t i o n . Yngve a t t r i b u t e s knowledge o f a s e t o f r e w r i t e r u l e s t o t h e a d u l t l anguage u s e r r a t h e r than t r a n s f o r m a -t i o n r u l e s . Because o f t h e d i f f e r e n c e i n t h e t y p e o f r u l e s t hough t t o be i n c o r p o r a t e d i n l o n g t e rm memory, q u i t e d i f f e r e n t p r e d i c t i o n s abou t p s y c h o l o g i c a l d i f f i c u l t y and on togeny o f t h e n o m i n a l a d j e c t i v e and a d j e c -t i v a l r e l a t i v e c l a u s e r e s u l t . P r e d i c t i o n s were made f rom b o t h mode l s i n t h e p r e s e n t s t u d y . I t was r e a s o n e d t h a t f o r m u l a t i o n o f a p e r f o r m a n c e mode l i n c o r p o r a t i n g a s e t o f t r a n s f o r m a t i o n r u l e s c o u l d be speeded by d e t e r m i n i n g where t h e p r e s e n t mode l f a i l s t o p r e d i c t p e r f o r m a n c e and by p e r h a p s l e a r n i n g someth ing f r om t h e p r e d i c t i v e s u c c e s s e s and f a i l u r e s o f a mode l s u c h a s Y n g v e ' s . To p r o v i d e a b a s i s f o r u n d e r s t a n d i n g t h e p r e d i c t i o n s made f r o m t h e two m o d e l s , t h e s t r u c t u r a l r e p r e s e n t a t i o n s and a s s u m p t i o n s about t h e l anguage u s e r a r e d i s c u s s e d b e l o w . The T r a n s f o r m a t i o n a l H y p o t h e s i s M i l l e r and Chomsky (1963) p r o p o s e d a p r e l i m i n a r y mode l o f p e r f o r -mance wh i ch i n c o r p o r a t e s a s e t o f c o n t e x t s e n s i t i v e p h r a s e - s t r u c t u r e r u l e s and t r a n s f o r m a t i o n r u l e s i n l o n g - t e r m memory s t o r a g e . A l t h o u g h the p r o -c e s s e s may d i f f e r i n some r e s p e c t s , p e r c e p t i o n and p r o d u c t i o n o f s e n t e n c e s a r e t h o u g h t t o t a ke p l a c e by r e f e r e n c e t o t h i s same s e t o f g e n e r a t i v e grammar r u l e s . B o t h a r e a l s o c h a r a c t e r i z e d as c o n s t r u c t i v e p r o c e s s e s . 28 L i n g u i s t i c i n p u t i s a n a l y z e d and t h e r e s u l t s o f t h e c o m p u t a t i o n s compared w i t h t h e c u r r e n t knowledge o f s t r u c t u r e . L i k e w i s e , t h e c o m p u t a t i o n s i n -v o l v e d i n s e n t e n c e p r o d u c t i o n a r e made i n r e f e r e n c e t o t h e c u r r e n t know-l e d g e o f s t r u c t u r e . I l i l l e r and Chomsky assumed t h a t p r e l i m i n a r y a n a l y -s i s and s t o r a g e o f t h e c o m p u t a t i o n s i n v o l v e s a s h o r t - t e r m memory component . I t was f u r t h e r assumed t h a t t h i s memory component h a s l i m i t e d c a p a c i t y . T h i s l a t e r a s s u m p t i o n i s c r i t i c a l t o a mode l o f p e r f o r m a n c e a s i t t a k e s i n t o a c c o u n t the d i s c r e p a n c y between p e r f o r m a n c e and competence . A l s o , i t a l l o w s f o r p r e d i c t i o n o f w h i c h s e n t e n c e s w i l l be c o r r e c t l y u n d e r s t o o d o r p r o d u c e d . S e n t e n c e s w h i c h r e q u i r e g r e a t e r comput ing and s t o r a g e s p a c e t h a n a v a i l a b l e i n s h o r t t e rm memory w i l l n o t be c o r r e c t l y u n d e r -s t o o d . I f s h o r t - t e r m memory has a c a p a c i t y o f 3 c o m p u t a t i o n s and t h * s e n t e n c e r e q u i r e s 4 c o m p u t a t i o n s , someth ing can be e x p e c t e d t o be l o s t i n t h e p r e l i m i n a r y a n a l y s i s . B e h a v i o r a l l y t h i s means a l a n g u a g e u s e r may n o t d e m o n s t r a t e comprehens ion o f o r may n o t p r o d u c e many s e n t e n c e s t h a t a r e p o s s i b l e g i v e n h i s l e v e l o f competence . I n o r d e r t o s t u d y t h e r e l a t i o n s h i p between t r a n s f o r m a t i o n a l c o m p l e x -i t y and p s y c h o l o g i c a l d i f f i c u l t y , p r e d i c t i v e i n d e x o f c o m p l e x i t y i s n e c e s -s a r y . Number o f ma jo r t r a n s f o r m a t i o n a l o p e r a t i o n s has been p r o p o s e d as a p o s s i b l e i n d e x o f t h e number o f c o m p u t a t i o n s . I t has been shown i n a number o f s t u d i e s w i t h a d u l t s t h a t the g r e a t e r t h e number o f t r a n s f o r -m a t i o n a l o p e r a t i o n s , t h e p o o r e r t h e r e c a l l o f t h e s e n t e n c e o r t h e l o n g e r t h e l a t e n c y o f r e s p o n s e ( C l i f t o n & Odom, 1966 ; Gough , 1 9 6 5 ; H e r r l o t , 1969 ; M e h l e r , 1963 ; S a v i n & P e r c h o n o c k , 1 9 6 5 ) . T h i s r e l a t i o n s h i p has a l s o been f o u n d t o h o l d w i t h c h i l d r e n ( H e r r l o t , 1968 ; S l o b l n , 1 9 6 6 ) . S i n c e memory c a p a c i t y i n c r e a s e s w i t h a g e , i t wou ld be e x p e c t e d t h a t a c h i l d w i l l n o t p r o d u c e o r comprehend s e n t e n c e s w h i c h r e q u i r e a number o f t r a n s f o r m a t i o n s In e x c e s s o f h i s memory c a p a c i t y . 29 The two s t r u c t u r e s o f p a r t i c u l a r i n t e r e s t i n t h e p r e s e n t s t u d y , t h e a d j e c t i v a l r e l a t i v e c l a u s e and n o m i n a l a d j e c t i v e , b o t h have a d o u b l e -b a s e d e r i v a t i o n . I n a d d i t i o n , t h e two s t r u c t u r e s a r e d e r l v a t i o n a l l y l i n k e d i n t h a t t h e a d j e c t i v e i s f o rmed by t r a n s f o r m a t i o n o f t h e s t r i n g f o rmed by a p p l i c a t i o n o f T - r e l . The f o r m a l d e r i v a t i o n o f t h e two s t r u c -t u r e s d i s c u s s e d be low s e r v e s as t h e f o u n d a t i o n f o r t h e p r e d i c t i o n s made abou t sequence o f deve lopment and p s y c h o l o g i c a l d i f f i c u l t y . Grammar o f t h e R e l a t i v e C l a u s e — T r a n s f o r m a t i o n a l . A c c o r d i n g t o t he t r a n s f o r m a t i o n m o d e l , t h e r e l a t i v e c l a u s e has a d o u b l e - b a s e d e r i v a t i o n . T h a t i s , t h e g r a m m a t i c a l r e l a t i o n s i n t h e s u r f a c e s t r u c t u r e a r e d e f i n e d b y t h e g r a m m a t i c a l r e l a t i o n s i n two u n d e r l y i n g b a s e s t r i n g s , o r t h e deep s t r u c t u r e . One s t r i n g ( m a t r i x ) p r o v i d e s t h e fo rm o f t h e s e n t e n c e t o be p r o d u c e d and t h e s e c o n d ( i n s e r t ) i s embedded i n t h e m a t r i x . The two s t r i n g s a r e j o i n e d t o g i v e the s u r f a c e s t r u c t u r e b y t h e r e l a t i v e c l a u s e t r a n s f o r m a t i o n r u l e . F o r m a l l y , t h e r u l e ( T - r e l ) may be r e p r e s e n t e d as f o l l o w s ( f r om R o b e r t s , 1 9 6 4 ) . T - r e l i n s e r t ; X ( 1 ) ~ N P (2 )—Y (3) m a t r i x : Z (4 )—NP (5)—W (6) who r e s u l t ; 4 + 5 + wh i ch + 1 + 3 + 6 t h a t The symbo l s X , Y , Z , and W mark t h e p o s i t i o n s o f symbo ls o t h e r t h a n t h e NP b e i n g m o d i f i e d . An example i s p r e s e n t e d b e l o w . i n s e r t : t he p o l i c e a r r e s t e d ( 1 ) — t h e boy ( 2 ) — l a s t n i g h t (3) m a t r i x : Mary s e n t ( 4 ) — t h e boy ( 5 )—some f l o w e r s (6 ) r e s u l t : Mary s e n t (4) + t h e boy (5) + t h a t + t h e p o l i c e a r r e s t e d (1) + l a s t n i g h t (3) + some f l o w e r s (6 ) Some o f t h e p o s i t i o n s may be empty a s i n t h e f o l l o w i n g example . 30 i n s e r t : t he p o l i c e a r r e s t e d (1)— the boy (2)—Y (3) m a t r i x : W (4)— t h e boy ( S ) — i s M a r y ' s f r i e n d (6) r e s u l t : 0 (4) + t h e boy (5) + t h a t + the p o l i c e a r r e s t e d (1) + 0 + i s M a r y ' s f r i e n d (6). The T - r e l i s r e a d i l y g e n e r a l i z a b l e i n t h a t any NP i n t h e m a t r i x c a n b e m o d i f i e d i n t h e manner s y m b o l i z e d , p r o v i d i n g t he i n s e r t s h a r e s the NP. As has been n o t e d , t h e s h a r e d NP may be i n one o f s e v e r a l p o s i t i o n s and s e r v e one o f s e v e r a l g r a m m a t i c a l f u n c t i o n s . A s e p a r a t e r u l e f o r r e o r d e r i n g w i t h i n t h e r e l a t i v e c l a u s e i s no t r e q u i r e d s i n c e t h e T - r e l s p e c i f i e s t h a t the r e l a t i v e p r o n o u n , whether s u b j e c t , o b j e c t , e t c . , f o l l o w s t h e NP i t w i l l m o d i f y . The o t h e r e l emen t s i n t h e c l a u s e f o l l o w w i t h o u t change i n o r d e r . The r e l a t i v e p ronoun i s a c t u a l l y r edundan t w i t h t h e noun i t m o d i -f i e s . To e l i m i n a t e t h e r edundancy an o p t i o n a l t r a n s f o r m a t i o n c a l l e d a d e l e t i o n t r a n s f o r m a t i o n ( T - d e l ) may be a p p l i e d . T h i s t r a n s f o r m a t i o n d e l e t e s t he r e l a t i v e p ronoun and t h e a u x i l i a r y o f the v e r b i f p r e s e n t . F o r e x a m p l e , " T h e r e i s a dog t h a t i s sitting on a b a l l " becomes " T h e r e ^ l s a dog s i t t i n g on a b a l l " . No te t h a t t h e p r e s e n t p a r t i c i p l e f o r m o f t h e v e r b i s u s e d and t h e T - d e l i s a p p l i c a b l e o n l y i f t h e s u b j e c t o f t h e i n -s e r t was t he NP s h a r e d by the m a t r i x . F o r m a l l y , the T - d e l may be r e p r e -s e n t e d as f o l l o w s : T - d e l : NP + r e l a t i v e p ronoun + t e n s e + be + X >NP + X T - d e l - i n g : NP + r e l a t i v e p ronoun + Aux + X >NP + i n g + X Grammar o f t h e A d j e c t l v e — T r a n s f o r m a t i o n a l . A c c o r d i n g t o t h e t r a n s f o r m a t i o n m o d e l , a l l noun p h r a s e s o f t h e fo rm " d e t + ad j + N" ( t h e y e l l o w f l o w e r ) a r e d e r i v e d f rom b a s e s t r i n g s o f t h e f o rm " d e t + N + b e + a d j " ( t h e f l o w e r i s y e l l o w ) . Any s e n t e n c e c o n t a i n i n g an a d -j e c t i v e i n t he n o m i n a l has a d o u b l e - b a s e d e r i v a t i o n a l h i s t o r y as do 31 s e n t e n c e s w i t h r e l a t i v e c l a u s e s f u n c t i o n i n g a s a d j e c t i v e c l a u s e s . F o r e x a m p l e , t h e s e n t e n c e " T h e g i r l p i c k e d t h e y e l l o w f l o w e r " d e r i v e s f r o m two b a s e s t r i n g s w h i c h may b e i n t e r p r e t e d a s " T h e g i r l p i c k e d t h e f l o w e r " a n d " T h e f l o w e r i s y e l l o w " . T h e u n q u a l i f i e d t e r m " t h e a d j e c t i v e " o r " a d j e c t i v e s e n t e n c e " w i l l b e u s e d i n t h e r e m a i n d e r o f t h e s t u d y t o r e f e r t o s e n t e n c e s w i t h a n a d j e c t i v e i n t h e n o m i n a l a s d i s t i n g u i s h e d f r o m s e n -t e n c e s w i t h a n a d j e c t i v e a s a p r e d i c a t e c o m p l e m e n t . T h r e e m a j o r r u l e s o f t r a n s f o r m a t i o n a r e i n v o l v e d i n t h e t r a n s i t i o n f r o m b a s e t o s u r f a c e s t r u c t u r e f o r a d j e c t i v e s i n t h e n o m i n a l . The t r a n s -f o r m a t i o n s a r e t h e T - r e l , T - d e l , a n d T - N M . T h e T - d e l r u l e i s o f p a r t i c -u l a r s i g n i f i c a n c e b e c a u s e i t f u n c t i o n s a s t h e d e r i v a t i o n a l l i n k b e t w e e n t h e r e l a t i v e c l a u s e a n d a d j e c t i v e . T h a t i s , t h e r e l a t i v e c l a u s e a n d a d j e c t i v e s t r u c t u r e s a r e d e r i v e d f r o m t h e same b a s e s t r i n g s , t h e a d j e c -t i v e s t r u c t u r e b e i n g f o r m e d b y o p e r a t i o n u p o n t h e r e s u l t o f T - r e l a n d T ^ d e l . I f a f t e r t h e a p p l i c a t i o n o f T - d e l t o t h e r e s u l t o f T - r e l , t h e m o d i f i e r i s a s i n g l e w o r d , t h e n t h e a p p l i c a t i o n o f a n o t h e r t r a n s f o r m a -t i o n , ( T - N M ) , i s o b l i g a t o r y . T h e T - N M r e a r r a n g e s w o r d o r d e r , p l a c i n g t h e m o d i f i e r i n f r o n t o f t h e n o u n . T h e r e s u l t i n g m o d i f i e r i s commonly r e f e r r e d t o a s t h e d e s c r i p t i v e a d j e c t i v e . B o t h b a s e - a n d v e r b - d e r i v e d a d j e c t i v e s a r e f o r m e d b y t h e a p p l i c a t i o n o f t h e t h r e e t r a n s f o r m a t i o n s . F o r e x a m p l e , " T h e r e i s a g i r l " a n d " T h e g i r l i s h a p p y " become " T h e r e i s a g i r l who i s h a p p y " b y a p p l i c a t i o n o f T - r e l , " T h e r e i s a g i r l h a p p y " ° y T - d e l a n d f i n a l l y , " T h e r e i s a h a p p y g i r l " b y T - N M . L i k e w i s e , " T h e r e i s a d o g " a n d " T h e dog i s b a r k i n g " become " T h e r e i s a dog t h a t i s b a r k -W b y T - r e l , " T h e r e i s a d o g b a r k i n g " b y T - d e l , a n d " T h e r e i s a b a r k -i n g d o g " b y T - N M . F o r m a l l y , T - N M may b e r e p r e s e n t e d a s f o l l o w s : T - N M : D e t + N + M o d i f i e r > D e t + M o d i f i e r + N L i k e t h e r e l a t i v e c l a u s e , t h e a d j e c t i v e may m o d i f y a n y NP o f a 32 m a t r i x — s u b j e c t , o b j e c t , o b j e c t o f t h e p r e p o s i t i o n o r i n d i r e c t o b j e c t . The s t r u c t u r e o f t h e r e l a t i v e c l a u s e f rom w h i c h t h e a d j e c t i v e d e r i v e s , however , I s l i m i t e d . The NP s h a r e d w i t h t h e m a t r i x I s a lways t h e s u b j e c t o f t h e r e l a t i v e c l a u s e . T h a t i s , n o t a l l r e l a t i v e c l a u s e s e n t e n c e s can be t r a n s f o r m e d by T - d e l and T-NM i n t o a d j e c t i v e s e n t e n c e s , b u t a l l a d j e c -t i v e s e n t e n c e s a r e d e r i v e d f r om r e l a t i v e c l a u s e s e n t e n c e s . P r e d i c t i o n s . In summary, (a) t h e a d j e c t i v e r e q u i r e s more t r a n s f o r -m a t i o n s t h a n t h e r e l a t i v e c l a u s e s e n t e n c e , and (b) b o t h t y p e s u l t i m a t e l y stem f r o m t h e same b a s e s t r i n g s . On the b a s i s o f t h e s e f o r m a l r e l a t i o n -s h i p s between the r e l a t i v e c l a u s e and a d j e c t i v e , t h e f o l l o w i n g g e n e r a l p r e d i c t i o n s c a n be made. 1. P a i r s o f s i m p l e a c t i v e s e n t e n c e s w i l l be comprehended and p r o d u c e d p r i o r t o r e l a t i v e c l a u s e o r a d j e c t i v e s e n -t e n c e s . * 2 . R e l a t i v e c l a u s e s e n t e n c e s w i l l be comprehended and p r o -d u c e d p r i o r t o a d j e c t i v e s e n t e n c e s . 3. More t i m e w i l l be r e q u i r e d t o comprehend r e l a t i v e c l a u s e t han p a i r s o f s i m p l e a c t i v e s e n t e n c e s . 4 . More t ime w i l l be r e q u i r e d t o comprehend s e n t e n c e s a d j e c t i v e t h a n r e l a t i v e c l a u s e s e n t e n c e s . 5. I n i m i t a t i n g an a d j e c t i v e o r r e l a t i v e c l a u s e s e n t e n c e , i f a c h i l d comprehends b u t c anno t p r o d u c e t h e s t r u c t u r e , he w i l l t e n d t o s i m p l i f y by p r o d u c i n g t h e two s i m p l e s e n t e n c e s t o w h i c h the complex s t r u c t u r e s a r e d e r i v a -t i o n a l l y r e l a t e d . The Dep th H y p o t h e s i s Yngve (1960 , 1964) h a s p r o p o s e d as mode l o f l a n g u a g e p e r f o r m a n c e w h i c h i s o r g a n i z e d much t h e same as M i l l e r and Chomsky ' s p e r f o r m a n c e m o d e l and r e q u i r e s some o f t h e same a s s u m p t i o n s . Yngve assumes as d i d *Examp les o f s e n t e n c e t y p e s a r e " T h e boy h o l d s t he a p p l e s . The boy i s h a p p y " ( p a i r o f s i m p l e s e n t e n c e s ) ; " T h e boy who i s happy h o l d s t h e a p p l e s " ( r e l a t i v e c l a u s e s e n t e n c e ) ; and " T h e happy boy h o l d s t h e a p p l e s " ( a d j e c t i v e s e n t e n c e ) . M i l l e r and Chomsky t h a t t h e memory c a p a c i t y o f t he human i s l i m i t e d . The consequences o f l i m i t e d memory and comput ing s p a c e on l i n g u i s t i c p e r f o r m a n c e a r e , however , v i ewed as somewhat d i f f e r e n t by Yngve . The grammar mode l h y p o t h e s i z e d t o be i n c o r p o r a t e d i n l o n g - t e r m memory by t h e u s e r i s a l s o v e r y d i f f e r e n t . U n l i k e M i l l e r and Chomsky, Yngve has s u g g e s t e d t h a t t h e l anguage u s e r i n c o r p o r a t e s o n l y a s e t o f o r d e r e d p h r a s e - s t r u c t u r e r u l e s w h i c h a r e a p p l i e d by e x p a n s i o n i n a l e f t - t o - r i g h t f a s h i o n . The l a n g u a g e u s e r ' s h y p o t h e s i z e d knowledge about t he two s t r u c t u r e s o f i n t e r e s t , t h e r e l a t i v e c l a u s e and a d j e c t i v e , d i f f e r s c o n s i d e r a b l y f r o m t h e knowledge a t t r i b u t e d t o t he l anguage u s e r f r o m t h e t r a n s f o r m a t i o n a l grammar. The f o r m a l r e p r e s e n t a t i o n o f t h e r e l a t i v e c l a u s e and a d j e c t i v e f o l l o w i n g a c o n s t i t u e n t s t r u c t u r e grammar f o l l o w s . Grammar o f t h e R e l a t i v e C l a u s e — C o n s t i t u e n t . A c o n s t i t u e n t - s t r u c -t u r e mode l does n o t d i s t i n g u i s h between deep and s u r f a c e s t r u c t u r e ( c f . , P o s t a l , 1 9 6 4 ) . S u r f a c e s t r u c t u r e i s d e r i v e d by t h e a p p l i c a t i o n o f a s e t o f e x p a n s i o n o r r e w r i t e r u l e s d i r e c t l y , r a t h e r t h a n by t r a n s f o r m a -t i o n o f two K - t e r m i n a l s t r i n g s . The r e l a t i o n s h i p be tween t h e r e l a t i v e c l a u s e s e n t e n c e and t h e two s e n t e n c e s u n d e r l y i n g t h e i n d e p e n d e n t and dependent c l a u s e s i s r e c o g n i z e d by t h e c o n s t i t u e n t - s t r u c t u r e grammar ian b u t n o t f o r m a l l y r e p r e s e n t e d a s i t i s i n t h e t r a n s f o r m a t i o n a l grammar ( e . g . , Emery , 1 9 6 1 ) . B a s i c a l l y , t h i s means t h a t the r e l a t i v e c l a u s e s e n t e n c e i s r e p r e s e n t e d a s d e r i v i n g f r om a s i n g l e S e n t e n c e r a t h e r t h a n f r o m S e n t e n c e ^ and Sen tence ^ a s wou ld be t h e c a s e u s i n g t h e t r a n s f o r -m a t i o n a l m o d e l . F o r m a l l y , a r e l a t i v e c l a u s e s e n t e n c e such as " T h e boy h o l d s t h e dog t h a t i s b a r k i n g " may be r e p r e s e n t e d In a t r e e d i a g r a m as f o l l o w s . N o t e t h a t t h e r e l a t i v e c l a u s e i s i n t r o d u c e d b y e x p a n s i o n o f t h e VP o r S en t ence (S) and a l s o t h a t t he e x p a n s i o n o f s ymbo l s i s a lways b i n a r y . 34 Grammar o f t h e A d j e c t i v e — C o n s t i t u e n t . The a d j e c t i v e Is r e p r e s e n t e d a s d e r i v i n g f r o m a s i n g l e Sen tence by e x p a n s i o n o f e i t h e r t h e NP^, W?^ o r V P . The a d j e c t i v e i s a l s o i n t r o d u c e d b y r e w r i t e r u l e s b y t h e t r a n s -f o r m a t i o n a l grammar when t h e v e r b p h r a s e (VP) c o n s i s t s o f a fo rm o f be f o l l o w e d by an a d j e c t i v e ( e . g . , The dog i s b l a c k ) . The a d j e c t i v e I s I n t r o d u c e d o n l y by t r a n s f o r m a t i o n o f two b a s e s t r i n g s , howeve r , when t h e a d j e c t i v e i s i n t h e n o m i n a l . I n c o n t r a s t , t h e Yngve mode l i n t r o -d u c e s t h e a d j e c t i v e i n t h e n o m i n a l by e x p a n s i o n o f t h e NP as f o l l o w s . NP d e t N VP / \ V NP / d e t t h e boy h o l d s t h e / \ a d j N b l a c k dog A l t h o u g h the l anguage u s e r and t h e s t r u c t u r a l l i n g u i s t ( i b i d . ) r e c o g n i -z e s t h e r e l a t i o n s h i p between s e n t e n c e s such as " T h e boy h o l d s t h e b l a c k d o g " and " T h e boy h o l d s t h e d o g . The dog i s b l a c k " , t h e r e l a t i o n s h i p i s n o t f o r m a l l y r e p r e s e n t e d as i t i s i n t h e t r a n s f o r m a t i o n a l m o d e l . 35 L i k e w i s e , t h e e q u i v a l e n c e o f t h e N o u n - A d j e c t i v e r e l a t i o n s h i p i n t h e two s t r i n g s , d e t + adr1 + N ( e . g . t h e happy b o y . . . ) and d e t + N + b e + a d j ( e . g . , t h e boy i s happy ) i s r e c o g n i z e d by t h e s t r u c t u r a l i s t b u t t he r e -l a t i o n s h i p i s n o t f o r m a l l y r e p r e s e n t e d i n t h e c o n s t i t u e n t - s t r u c t u r e grammar.. P e r f o r m a n c e . Knowledge o f a s e t o f r e w r i t e r u l e s s u c h a s t h o s e d e s c r i b e d above f o r t h e a d j e c t i v e and r e l a t i v e c l a u s e a r e a t t r i b u t e d t o t h e l a n g u a g e u s e r b y Yngve . He t h e n p r e c e d e s t o a r g u e t h a t i n o r d e r t o p r o d u c e a s e n t e n c e , i t i s n e c e s s a r y t o h o l d i n memory o r p o s t p o n e t h e c o n s t i t u e n t s t h a t f o l l o w t h e one b e i n g e x p a n d e d , and t h a t t he more symbo l s t h a t must be h e l d i n memory t h e g r e a t e r i s t h e d e p t h o f a w o r d . The d e p t h o f a s e n t e n c e i s d e t e r m i n e d by c o u n t i n g t h e number o f s ymbo l s t o t h e r i g h t o f the symbol b e i n g expanded t h a t must be h e l d i n memory. E x p a n s i o n i s c h a r a c t e r i z e d as a l e f t - t o - r i g h t p r o c e s s , b e g i n n i n g a t t h e t op o f t h e t r e e . F i r s t , S i s r e w r i t t e n a s NP + V P , t h e n NP i s r e w r i t t e n , and so o n , as d e m o n s t r a t e d i n t h e f o l l o w i n g examp le . NP / \ d e t N t h e boy h o l d s V NP d e t ' \ [ I I t h e dog W h i l e d e t i s b e i n g r e w r i t t e n as " t h e " , two s y m b o l s , N and VP must b e h e l d i n memory a s e x p a n s i o n o f t h e s e symbols has no t been c o m p l e t e d . " T h e " wou ld t h e r e f o r e , b e a s s i g n e d a d e p t h o f 2. W h i l e N i s b e i n g r e w r i t t e n a s " b o y " o n l y one s ymbo l » VP , must be h e l d i n memory. " B o y " wou ld be a s s i g n e d a d e p t h o f 1. F o r each word i n t h e s e n t e n c e , t h e number o f 36 symbo l s t o t h e r i g h t t h a t must be h e l d i n immed ia te memory c a n be d e t e r -m i n e d . The d e p t h o f each word i n t h e s e n t e n c e " T h e boy h o l d s t h e d o g " wou ld be 2, 1, 1, 1, 0 , r e s p e c t i v e l y . Yngve a s s i g n e d t h e h i g h e s t num-b e r a s t h e d e p t h o f t h e s e n t e n c e ; t he example has a d e p t h o f 2 . A c c o r d -i n g t o t h e Dep th H y p o t h e s i s t h i s s e n t e n c e s h o u l d p o s e no p r o b l e m f o r t h e a d u l t s p e a k e r s i n c e i t i s w e l l be low t h e l a n g u a g e u s e r ' s span o f immed-i a t e memory, assumed t o b e 7 + 2 o n t h e b a s i s o f M i l l e r ' s r e s e a r c h ( 1956 ) . A s e n t e n c e w i t h a d e p t h o f 7 o r 8 , however , may e x c e e d t h e s p e a k e r ' s c a p a c i t y t o remember t h e pos tponements o f s y m b o l s . Yngve m a i n t a i n s t h a t t h e s p e a k e r w i l l a v o i d s u c h c o n s t r u c t i o n s s i n c e h e u s u a l l y h a s t o back up and s t a r t anew when he a t t e m p t s t o u s e c o n s t r u c t i o n s t h a t a r e too comp lex . A measure o f s e n t e n c e c o m p l e x i t y b a s e d on d e p t h has been p r o p o s e d b y M a r t i n and R o b e r t s ( 1966 ) . T h i s measure i s t he mean o f t h e numbers o b t a i n e d f o r a s e n t e n c e by Y n g v e ' s method and i s c a l l e d mean d e p t h . Mean d e p t h f o r a s e n t e n c e i s c a l c u l a t e d b y summing t h e number o b t a i n e d f o r a who l e s e n t e n c e and d i v i d i n g b y t h e number o f wo rds . F o r t h e s e n -t e n c e " T h e boy h o l d s t h e d o g " , mean d e p t h i s 5/5 o r 1. M a r t i n and R o b e r t s have u s e d mean d e p t h as an i n d e x o f s t r u c t u r a l c o m p l e x i t y , p r e d i c t i n g t h a t i r r e s p e c t i v e o f t he k i n d o f s e n t e n c e ( a c -t i v e , p a s s i v e , q u e s t i o n , r e l a t i v e c l a u s e , e t c . ) , t he g r e a t e r t he mean d e p t h , t h e p o o r e r w i l l be t h e r e c a l l o f t h e s e n t e n c e . The r e s u l t s o f a number o f s t u d i e s w i t h a d u l t s have p r o d u c e d i n c o n s i s t e n t r e s u l t s ( M a r t i n £ R o b e r t s , 1 9 6 7 ; M a r t i n , R o b e r t s & C o l l i n s , 1968 ; P e r f e t t l , 1 9 6 9 ; R o b e r t s , 1 9 6 8 ; and Rohrman, 1 9 6 8 ) . Such i n c o n s i s t e n c y makes i t e x t r e m e l y d i f f i c u l t t o g e n e r a l i z e t o c h i l d r e n . I f t h e mean d e p t h i n d e x were a r e l i a b l e p r e d i c t o r o f s e n t e n c e d i f f i c u l t y f o r c h i l d r e n , i t m igh t b e e x -p e c t e d t h a t , i r r e s p e c t i v e o f the s t r u c t u r e o f t h e s e n t e n c e , t h e g r e a t e r 37 t he mean d e p t h , t h e l a t e r i n deve lopment wou ld a s e n t e n c e o f t h a t c o m -p l e x i t y be p r o d u c e d . A l s o , r e c a l l wou ld be e x p e c t e d t o be p o o r e r . In t h e 1950 p a p e r , Yngve d i d no t expand h i s h y p o t h e s i s t o c o v e r p e r c e p t i o n and comprehens ion b u t t h e r e i s no r e a s o n t o assume t h a t t he same r e l a -t i o n s h i p be tween d e p t h and d i f f i c u l t y wou ld n o t h o l d . The i n f l u e n c e o f d e p t h migh t n o t be e x p e c t e d t o b e as g r e a t , hoxtfever, f o r comprehens ion as f o r p r o d u c t i o n and i m i t a t i o n s i n c e l e s s i n f o r m a t i o n p r o b a b l y h a s t o be h e l d i n memory d u r i n g a n a l y s i s o f i n p u t t han i n c r e a t i o n o f o u t p u t . A l s o comprehens i on p r o b a b l y r e q u i r e s l e s s c o m p u t a t i o n t i m e , hence t h e i n t e g r i t y o f t h e s t r u c t u r e i s more l i k e l y t o be r e t a i n e d d u r i n g a n a l y s i s ( M c N e i l l , 1 9 6 8 ) . A l t h o u g h t h e r e may be an o v e r a l l d i f f e r e n c e i n p e r f o r -mance between p r o d u c t i o n and c o m p r e h e n s i o n , t he o r d e r i n g o f s e n t e n c e d i f f i c u l t y f o r Ss s h o u l d be the same f o r b o t h comprehens ion and p r o d u c -t i o n , a f u n c t i o n o f mean d e p t h . P r e d i c t i o n s . P r e d i c t i o n s made o n the b a s i s o f t h e Depth H y p o t h e s i s c an o n l y be made f o r s p e c i f i c s e n t e n c e s , n o t f o r c l a s s e s o f s e n t e n c e s such as a d j e c t i v e o r r e l a t i v e c l a u s e , as was p o s s i b l e w i t h the number o f t r a n s f o r m a t i o n s i n d e x . P r e c i s e p r e d i c t i o n s w i l l b e made i n t h e method s e c t i o n s when t h e s p e c i f i c s e n t e n c e s t o be u s e d i n t he s t u d y a r e p r e -s e n t e d . V e r y g e n e r a l p r e d i c t i o n s , however , c an be s t a t e d on t h e b a s i s o f t h e Depth H y p o t h e s i s . 1. S en t ences h a v i n g l ow mean dep th s c o r e s w i l l be p r o d u c e d p r i o r t o s e n t e n c e s h a v i n g h i g h s c o r e s . 2. S en t ences h a v i n g low mean d e p t h s c o r e s w i l l be c o r r e c t l y i m i t a t e d and comprehended e a r l i e r t h an s e n t e n c e s w i t h h i g h mean d e p t h s . 3. S e n t e n c e s h a v i n g low mean dep th s c o r e s w i l l be more a c c u r a t e l y i m i t a t e d and comprehended t han s e n t e n c e s h a v i n g h i g h mean d e p t h a t a l l a g e s . A. More t ime w i l l be r e q u i r e d t o comprehend s e n t e n c e s h a v i n g h i g h mean d e p t h than s e n t e n c e s w i t h low mean d e p t h . 38 The Depth and Transformational Hypotheses actually led to di f f e r e n t i a l predictions regarding the sequence of emergence in production and the order of d i f f i c u l t y in imitation and comprehension of adjective and re-lative clause sentences. The Depth Hypothesis predicted earlier emer-gence in speech and a higher level of imitation and comprehension per -formance for adjective than for relative clause or simple sentences. On the other hand, the Transformational Hypothesis predicted that adjective sentences would show later emergence in speech and a low level of imi-tation and comprehension performance since adjective sentences require more transformations than the relative clause and also since the relative clause i s derivationally prior to the nominal adjective. The above discussion of the Depth and Transformation Hypotheses has focused on predictions about ontogeny and d i f f i c u l t y of sentences related to type of sentence, relative clause or adjective. Other fac-tors such as locus of a structure in a sentence may also be important performance variables that must be taken into consideration in attempt-ing to evaluate the adequacy of the transformational model as a dual performance-competence model. Embeddedness An important characteristic of generative grammar rules, phrase-structure or transformational, i s that there i s no limit to the number of times that the same rule can be applied in the derivation of a sen-tence. This characteristic is called recursiveness. The structure resulting from recursive application of a rule Is said to be embedded in the original string. On the basis of the Transformational Hypothesis It would be predicted that the more embeddings, the greater the d i f f i -culty of r e c a l l since each embedding requires additional transformational operations. Similarly, i t would be predicted on the basis of the Depth Hypothesis that the more embedding, the greater the d i f f i c u l t y of r e c a l l since each embedding requires postponement of symbols to the right. For example, the sentence "The man watching the boy i s eating an apple" has one embedding and would be expected from both hypotheses to be easier for children to r e c a l l than the sentence "The man watching the boy catching the b a l l Is eating an apple," which has two embeddings. Recent research with adults and children has confirmed the predictions made on the basis of the two hypotheses (Miller & Isard, 1964; Gaer, 1969). In addition to number of embeddings, locus of embedding has also been found to be an important performance variable. Generative grammar rules may be applied more than once in three major locations i n a sen-tence—beginning, middle and end. V/hen the insert sentence occurs at the beginning of the matrix sentence as in "John's father's brother i s a banker," the sentence i s called left-recursive. When the insert sentence occurs i n the middle of the matrix sentence as i n "The man watching the boy i s eating an apple," the sentence i s called s e l f -embedded. When the insert sentence occurs at the end of the matrix sen-tence as in "The man i s watching the boy catching the b a l l , " the sen-tence i s called right-recursive. It has been found that for speakers of English, right-recursive sentences are easiest to re c a l l , left-recursive more d i f f i c u l t , and self-embedded most d i f f i c u l t (Forster, 1966, 1967, 1968). These find-ings would not be predicted on the basis of the Transformational model. Derivationally, the three types of recursive sentences do not di f f e r , i.e., the same number and kind of transformations are involved In the derivation of a self-embedding sentence as a right-recursive. The Depth Hypothesis, however, does predict that, given identical meaning, se l f -embedded and l e f t - r e c u r s i v e s e n t e n c e s w i l l b e more d i f f i c u l t t h a n r i g h t -r e c u r s i v e . I n g e n e r a l t h e mean dep ths o f s e l f - e m b e d d e d and l e f t -r e c u r s i v e s e n t e n c e s a r e f o u n d t o b e h i g h e r t h a n r i g h t - r e c u r s i v e ( Y n g v e » 1 9 6 4 ) . P r e d i c t i o n s . On t h e b a s i s o f p r e v i o u s r e s e a r c h t h e f o l l o w i n g p r e d i c -t i o n s were made f o r t h e p r e s e n t s t u d y . From D e p t h H y p o t h e s i s 1. S en t ences h a v i n g h i g h mean d e p t h w i l l a p p e a r l a t e r i n s p e e c h t han t h o s e w i t h l ow mean dep th and w i l l r e s u l t i n more i m i t a t i o n and c o m p r e h e n s i o n e r r o r s . 2. R i g h t - r e c u r s i v e s e n t e n c e s w i l l a p p e a r e a r l i e r i n s p e e c h t h a n s e l f - e m b e d d e d s e n t e n c e s . 3. More e r r o r s w i l l be made on i m i t a t i o n and c o m p r e h e n s i o n o f se l f -embedded , r e l a t i v e c l a u s e s e n t e n c e s t h a n on r i g h t - r e c u r s i v e s e n t e n c e s . From T r a n s f o r m a t i o n a l H y p o t h e s i s 1. No d i f f e r e n c e s i n d i f f i c u l t y o r o n t o g e n y o f s e l f -embedded and r i g h t - r e c u r s i v e i s e x p e c t e d on t h e b a s i s t h e number o f t r a n s f o r m a t i o n s i n d e x o f s t r u c t u r a l c o m p l e x i t y . S i n c e the s i n g l e word a d j e c t i v e does n o t r e p r e s e n t an example o f r e c u r s i v e n e s s i n t h e c o n s t i t u e n t - s t r u c t u r e grammar, no d i f f e r e n t i a l p r e d i c t i o n about t h e e f f e c t o f l o c u s o f t h e a d j e c t i v e (NP o r NP^) i n s e n t e n c e s h a v i n g t h e f o rm "NP^ + V + NP^" c o u l d be made on t h e b a s i s o f t h e Dep th H y p o t h e s i s . L o c u s o f t he a d j e c t i v e was t r e a t e d a s a v a r i a b l e i n t h e p r e s e n t e x p e r i m e n t , however , b e c a u s e o f t he t r a n s f o r m a t i o n a l grammar r e p r e s e n t a t i o n o f common d e r i v a t i o n o f t h e r e l a t i v e c l a u s e and a d j e c t i v e . I f t h e t r a n s f o r m a t i o n a l r e p r e s e n t a t i o n o f the a d j e c t i v e has p s y c h o l o g i c a l r e l e v a n c e , t h e a d j e c t i v e i n NP^ s h o u l d be as d i f f i c u l t a s t h e s e l f - e m b e d d e d r e l a t i v e c l a u s e and s h o u l d b e more d i f f i c u l t t h a n t h e a d j e c t i v e i n HP , even though a low dep th i s a s s i g n e d o n t h e b a s i s o f 41 the s u r f a c e s t r u c t u r e . The T a s k s Most o f t h e g e n e r a l i z a t i o n s about l anguage a c q u i s i t i o n have been b a s e d on n a t u r a l i s t i c o b s e r v a t i o n s o v e r an ex tended p e r i o d o f t ime ( e . g . , Brown & B e l l u g i , 1964 ; B rown, 1 9 6 9 ) . The t e c h n i q u e has p r o v e n u s e f u l i n g e n e r a t i n g h y p o t h e s i s about what t h e c h i l d l e a r n s about t h e s t r u c t u r e o f l anguage and i n p l o t t i n g the c o u r s e o f deve lopment o f s p e c i f i c s t r u c -t u r e s . T h e r e a r e l i m i t a t i o n s , howeve r , i n h e r e n t i n t h e t e c h n i q u e . These i n c l u d e the r e s t r i c t i o n on t h e number o f s u b j e c t s and age r ange t h a t c an be e f f e c t i v e l y s t u d i e d i n a r e a s o n a b l e p e r i o d o f t i m e b y a s i n g l e i n v e s t i g a t o r . A g r e a t number o f h o u r s o f speech must be r e c o r d e d and a n a l y z e d i n o r d e r t o w r i t e a grammar f o r even one c h i l d ' s s p e e c h , and the amount I n c r e a s e s i n an a c c e l e r a t e d f a s h i o n w i t h t h e age o f t h e c h i l d . A second l i m i t a t i o n i n v o l v e s I n t e r p r e t a t i o n o f speech p r o d u c -t i o n s , p a r t i c u l a r l y ambiguous u t t e r a n c e s . I n t e r p r e t a t i o n i s o f t e n d i f f i c u l t b e c a u s e o f t h e l a c k o f i n f o r m a t i o n a b o u t , o r c o n t r o l o v e r , t he s t i m u l i e l i c i t i n g t h e p r o d u c t i o n s . I n t r o d u c t i o n o f e x p e r i m e n t a l m a n i p u l a t i o n i s g e n e r a l l y u n d e s i r a b l e i n a l o n g i t u d i n a l s t u d y b e c a u s e o f t h e p o s s i b i l i t y o f i n f l u e n c i n g l a t e r o b s e r v a t i o n s . I n a d d i t i o n , i n f e r e n c e s about t h e c h i l d ' s l i n g u i s t i c competence made o n t h e b a s i s o f a s i n g l e pe r f o rmance i n d e x , spon taneous s p e e c h , may g r e a t l y o v e r e s t i m a t e o r u n d e r e s t i m a t e the c h i l d ' s know ledge . Absence o f a s t r u c t u r e i n t he c o r p u s i s p a r t i c u l a r l y d i f f i c u l t to i n t e r p r e t and may l e a d t o u n d e r -e s t i m a t i o n o f t h e c h i l d ' s competence . In an a t t emp t t o overcome some o f t h e s h o r t c o m i n g s o f t he l o n g i -t u d i n a l - n a t u r a l i s t i c a p p r o a c h , t h e p r e s e n t s t u d y (1) employs a c o n t r o l l e d s e t o f s t i m u l u s m a t e r i a l s ; (2) u s e s t h r e e p r o c e d u r e s , each mak ing q u i t e 42 different demands on the subject; and <3) makes use of the cross-sec-tional technique so as to increase the number of subjects and age range studied. The three procedures employed were production, imitation, and comprehension. Because of the differences in the nature of the input and the response requirements, each procedure provided a different kind of information about the child's grammatical knowledge. Considered together, the results of the three procedures were expected to provide a clearer, less ambiguous basis for inferring the child's knowledge of a structure than any one procedure. This rationale for the use of production, imitation, and comprehension procedures represents a some-what different orientation to the problem of tracing the development of a structure. Generally, when an experimenter employs these three procedures, he is asking the question, "What are the differences l n per-formance on these tasks?" in an attempt to determine the relationship between comprehension and production (e.g., Fraser, et a l . , 1963). That i s , his question about performance on the tasks is put such that his interest i s in the differences or contrasts between the procedures per  se, rather than in the procedures as complementary sources of informa-tion about competence. Util i z a t i o n in the present study of these pro-cedures as complementary sources of information for inferring the child's l i n g u i s t i c knowledge required that some basic assumptions about the nature of the information each procedure provided be made explicit. A brief description of each procedure and the rationale for the data inter-pretation follows. Comprehension Procedure. For the comprehension procedure E showed a set of two or four pictures and read a sentence that was descriptive of one of the set. The S was asked to point to the picture that matched t h e s e n t e n c e r e a d by E. The S_ made no v e r b a l r e s p o n s e . C h o i c e o f t he c o r r e c t r e s p o n s e a l t e r n a t i v e was i n t e r p r e t e d a s i n d i c a t i n g t h a t t h e c h i l d u n d e r s t o o d t h e s e n t e n c e s s e m a n t i c a l l y and s y n t a c t i c a l l y . T h i s i n t e r p r e t a t i o n o f comprehens i on d a t a and t h e r a t i o n a l e f o r i t s u s e as a complementary s o u r c e o f i n f o r m a t i o n about l i n g u i s t i c competence were b a s e d on p a p e r s c o n c e r n e d w i t h the r e l a t i o n s h i p o f comprehens ion and p r o d u c t i o n p e r f o r m a n c e . I t i s g e n e r a l l y h e l d t h a t comprehens ion o f s t r u c t u r e s i n speech p r e c e d e s p r o d u c t i o n ( F r a s e r , B e l l u g i , & Brown, 1963 ; L o v e l l & D i x o n , 1 9 6 5 ; M c N e i l l , 1966 , 1968 ) . T h i s o b s e r v a t i o n has two m e a n i n g s : (1) on any g i v e n s e t o f s e n t e n c e s , some o f wh i ch exceed t h e c h i l d ' s comprehen -s i o n , s u c c e s s i n comprehens i on w i l l exceed t h a t i n p r o d u c t i o n and (2) s t r u c t u r e s t h a t a r e n o t comprehended w i l l n o t be p r o d u c e d e x c e p t as mem-o r i z e d s e q u e n c e s . M c N e i l l (1968) has h y p o t h e s i z e d t h a t b o t h the s u p e r i o r i t y and p r i o r i t y o f comprehens ion o v e r p r o d u c t i o n can b e a c c o u n t e d f o r as f o l l o w s P r o d u c t i o n r e q u i r e s more c o m p u t a t i o n t ime t h a n comprehens ion and s i n c e c o m p u t a t i o n must t a ke p l a c e w i t h i n a l i m i t e d p e r i o d , some s e n t e n c e s w i l l be p r o -c e s s e d r a p i d l y enough t o be r e t a i n e d i n comprehen -s i o n b u t n o t r a p i d l y enough t o be p r o d u c e d o r r e p r o -duced ( i b i d . , p . 1 3 3 ) . By c o m p u t a t i o n M c N e i l l i s r e f e r r i n g t o t he h y p o t h e t i c a l o p e r a t i o n s t h a t t a k e p l a c e i n p r o d u c i n g o r comprehend ing s p e e c h . M c N e i l l I s i n e s s e n c e a r g u i n g t h a t t h e s e t o f r u l e s w h i c h g o v e r n the c o m p u t a t i o n s a r e i d e n t i -c a l , b u t t he t ime i t t a k e s f o r c o m p u t a t i o n i s l e s s f o r comprehens ion t h a n i m i t a t i o n . Time i s t hough t t o be p a r t i c u l a r l y c r i t i c a l t n t h a t i f t oo l o n g a p e r i o d e l a p s e s d u r i n g c o m p u t a t i o n , t h e s t r u c t u r e o f the s e n -t e n c e c o l l a p s e s . The i m p o r t a n c e o f t ime and ma in t enance o f s t r u c t u r a l i n t e g r i t y c o u l d b e d e m o n s t r a t e d by compar ing r e c a l l o f s t r u c t u r e d and u n s t r u c t u r e d s t r i n g s p r e s e n t e d a t no rma l speech r a t e and a t a s l o w e r 44 r a t e . M c N e i l l p r e s e n t s two advan t ages o f h i s t ime-based a c c o u n t i n g o f t h e c o m p r e h e n s i o n - p r o d u c t i o n d i s c r e p a n c y o v e r p r e v i o u s a c c o u n t i n g s . One advan tage o f t h e c u r r e n t h y p o t h e s i s i s t h a t i t makes a n a l y s i s - b y - S y n t h e s i s i n t o a c r e d i b l e t h e o r y o f l i n g u i s t i c p e r f o r m a n c e by c h i l d r e n . T h i s t h e o r y c l a i m s t h a t s e n t e n c e s a r e U n d e r s t o o d by c o n -s t r u c t i n g an i n t e r n a l s e n t e n c e t h a t matches t h e a c o u s t i c i n p u t . I f i t i s a c t u a l l y t h e c a s e t h a t com-p r e h e n s i o n d e v e l o p s e a r l i e r t h an p r o d u c t i o n , compre -h e n s i o n c l e a r l y c o u l d n o t be a c h i e v e d t h r o u g h a n a l y s i s -by s y n t h e s i s . But t h e p r e s e n t h y p o t h e s i s c l a i m s t h a t t h e same l i n g u i s t i c knowledge i s i n v o l v e d i n b o t h comprehens ion and p r o d u c t i o n , and t h e mechanism o f comprehens i on c o u l d be ( f o r a l l we know) a n a l y s i s -b y - s y n t h e s i s . A s e c o n d advan t age i s t h a t t h e h y p o t h e s i s i n t r o d u c e s a c o n t i n u i t y between c h i l d r e n and a d u l t s , whereas b e f o r e t h e r e had been a d i s c o n t i n u i t y . P e rhaps a d u l t s c a n comprehend some fo rms w i t h o u t b e i n g a b l e t o p roduce them, b u t I f t h i s i s t r u e , i t i s n o t b e c a u s e s y n t a c t i c fo rms a r e u n a v a i l a b l e t o p r o d u c t i o n . The same c l a i m i s made i n b e h a l f o f c h i l d r e n . Forms t h a t a r e comprehended b u t n o t p r o d u c e d a r e a l s o a v a i l a b l e t o p r o d u c t i o n . They do no t appea r because p r o d u c t i o n r e q u i r e s t o o much t ime ( i b i d . , p. 133-184 ) . A c c o r d i n g t o t h i s v i e w p o i n t comprehens ion s h o u l d be a more a c c u r a t e p e r f o r m a n c e i n d e x o f l i n g u i s t i c competence t han p r o d u c t i o n i f a p p r o p r i -a t e p r o c e d u r e s c a n be d e v i s e d . O t h e r s have a l s o made t h i s same assump-t i o n (Chomsky, 1 9 6 4 ; Menyuk, 1 9 6 9 ) . The i m p o r t a n c e o f m a t e r i a l s and p r o c e d u r e canno t be u n d e r e s t i m a t e d . The u s e f u l n e s s o f comprehens ion as an i n d e x o f competence r e l i e s on t h e e l i m i n a t i o n o f t h e p o s s i b i l i t y o f c o r r e c t r e s p o n d i n g s o l e l y on t h e b a s i s o f n o n - s t r u c t u r a l c u e s . I f t h i s p o s s i b i l i t y i s e l i m i n a t e d , c o r r e c t r e s p o n s e s o n t h e comprehens i on t a s k can c o n f i d e n t l y be I n t e r p r e t e d as e v i d e n c e o f knowledge o f t h e s t r u c t u r e s i n v o l v e d . L i k e w i s e , e r r o r s c an be i n t e r p r e t e d as l a c k o f knowledge . As a p o t e n t i a l l y more a c c u r a t e p e r f o r m a n c e i n d e x o f compe-t e n c e t h a n p r o d u c t i o n , when Ss f a i l t o p r o d u c e a s y n t a c t i c s t r u c t u r e 45 in imitation or spontaneous speech, referral to their comprehension performance on a sentence having the same structure and content should reveal whether the absence indicates lack of knowledge of the structure or that i t just required too much computation time to produce accurately. Imitation Procedure. For the imitation procedure no pictures were presented. The E read sentences having the same structure and content as those read for the comprehension task one at a time. The S_ was asked to imitate each sentence after i t was read. As with a comprehension procedure i t i s possible to make systema-t i c comparisons among grammatical structures on the basis of total num-ber of Imitation errors. Structures which result in more errors are assumed to be at an earlier level of development and/or require more psychological operations or computations. An imitation procedure had one decided advantage over comprehension ln that i t offers considerable information about lin g u i s t i c knowledge i n the form of errors. That i s , i t i s not only possible to evaluate structural compexity by the number of errors but also by the kinds of errors. It has been observed that the modifications that children make in their responses (omissions, substitutions, and additions) are systematic both within and between children (Brown, 1968; Menyuk, 1963, 1969). Since the modifications are systematic, It i s assumed that they reflect what the child under-stood and how this understanding would be expressed following the rules of his grammar. More specifically, this assumption means that the modifications reflect the structural forms that the child i s able to produce within the limits of his computing capacity. These modifica-tions i n structure thus would be expected to represent simplifications of the more complex structure that was understood but required too much time to produce. 46 E r r o r a n a l y s i s o f i m i t a t i o n d a t a i n t h i s e x p e r i m e n t was e x p e c t e d t o be a p a r t i c u l a r l y u s e f u l s o u r c e o f i n f o r m a t i o n about t h e c h i l d ' s s y n t a c t i c know ledge . F o r examp le , when a £ f a i l s t o p r o d u c e a s y n t a c t i c s t r u c t u r e o f i n t e r e s t i n a spon taneous s p e e c h s a m p l e , r e f e r r a l t o h i s i m i t a t i o n p e r f o r m a n c e on the s t r u c t u r e s h o u l d i n d i c a t e whe the r t h e s t r u c t u r e was w i t h i n t h e l i m i t s o f h i s p r o d u c t i o n c a p a b i l i t i e s and what s i m p l i f i e d o r a l t e r n a t e f o r m t h e s t r u c t u r e t o o k i f i t d i d e x c e e d p r o d u c t i o n l i m i t a t i o n s . Spontaneous P r o d u c t i o n P r o c e d u r e . I t i s n e c e s s a r y t o d e f i n e c a r e -f u l l y what i s meant by spon taneous p r o d u c t i o n i n t h i s e x p e r i m e n t s i n c e t h e d a t a c o l l e c t i o n p r o c e d u r e d i f f e r e d f rom t h e s t a n d a r d o n e . S p o n t a n e -ous p r o d u c t i o n d a t a i s g e n e r a l l y o b t a i n e d by t a p e - r e c o r d i n g t i m e samp les o f a c h i l d ' s s p e e c h i n t h e home, a p r o c e d u r e w h i c h has some i m p o r t a n t d i s a d v a n t a g e s . F i r s t , t h e number o f u t t e r a n c e s t h a t must be c o l l e c t e d and a n a l y z e d i s s t a g g e r i n g , and even a l a r g e c o r p u s does n o t e n s u r e t h a t t h e absence o f a s t r u c t u r e w i l l be r e a d i l y i n t e r p r e t a b l e . I t c o u l d b e t h a t t h e c h i l d i s n o t c a p a b l e o f p r o d u c i n g the s t r u c t u r e o r t h a t he s i m p l y d i d n o t p r o d u c e i t d u r i n g t h e t ime samples o b t a i n e d . The f a c t t h a t the c o n t r o l l i n g s t i m u l i f o r an u t t e r a n c e a r e o f t e n n o t i d e n t i f i e d o r a r e u n i d e n t i f i a b l e f u r t h e r h a n d i c a p s the e x p e r i m e n t e r i n I n t e r p r e t i n g h i s d a t a . I n t he p r e s e n t s t u d y spon taneous p r o d u c t i o n d a t a was o b t a i n e d b y p r e s e n t i n g p i c t u r e s f r om t h e comprehens i on p r o c e d u r e t o a l l s u b j e c t s and i n s t r u c t i n g t h e c h i l d t o v e r b a l l y d i s t i n g u i s h one p i c t u r e f rom t h e o t h e r w h i l e p l a y i n g a game w i t h E. S i n c e p a i r s o f p i c t u r e s d i f f e r e d o n l y i n one a t t r i b u t e , m o d i f i c a t i o n o f t h e noun was n e c e s s a r y t o v e r b a l l y d i s t i n g u i s h the p i c t u r e s . By m a x i m i z i n g the l i k e l i h o o d o f o b t a i n i n g t h e d e s i r e d s t r u c t u r e s i n t h i s way, a s m a l l e r c o r p u s o f d a t a was r e q u i r e d 47 to obtain many instances of the structures than would usually be re-quired. It was assumed that under these constrained conditions, absence of the desired structures could more confidently be interpreted as lack of productive control of the structure. In addition, the hypothe-si s of lack of control could be submitted to test by referral to comple-mentary comprehension and imitation data. Order of Tasks and Procedures; An Overview. Each child was tested on two sets of materials (Task 1 and Task 2) using each of three pro-cedures (Production, Imitation and Comprehension). A l l Ss received the procedures in the same sequence: Production, Imitation, Comprehen-sion. Imitation preceded Comprehension to avoid the possibility of an J5's u t i l i z i n g his memory of a picture used in the Comprehension proce-dure to mediate r e c a l l . Production, of course, preceded both Compre-hension and Imitation to avoid the pos s i b i l i t y of S_ having memorized sequences or names of the pictures. Task 1 always preceded Task 2. Because age within and between the two groups (Group 2-3 and Group 4-5) varied, order was kept constant to avoid possible confound-ing of Age and Order of tasks and procedures. A minimum of four sessions with each child tras required. Produc-tion, Imitation, and Comprehension sessions were separated by at least a week for a l l Ss. Task 1 and Task 2 were given on successive days when possible, otherwise with one intervening day. For exposition purposes the presentation of the method, results and discussion of Task and Procedures does not follow the order In which they were given to the Ss. Quantitative and Qualitative results are presented individually, as are Task 1 and 2. The basic findings of the entire experiment are discussed i n the f i n a l section, General  Discussion and Conclusions. 48 Summary o f M a j o r H y p o t h e s e s T h e b a s i c e x p e c t a t i o n s r e g a r d i n g o n t o g e n y , c o m p r e h e n s i o n a n d I m i -t a t i o n a r e s u m m a r i z e d b e l o w f o r s y n t a x a n d l o c u s o f e m b e d d i n g . (The " > : s y m b o l s h o u l d b e i n t e r p r e t e d a s " e a r l i e r t h a n " f o r o n t o g e n y p r e d i c t i o n s a n d a s "mean number c o r r e c t g r e a t e r t h a n " f o r c o m p r e h e n s i o n a n d i m i t a -t i o n p r e d i c t i o n s . ) T r a n s f o r m a t i o n H y p o t h e s i s D e p t h H y p o t h e s i s S y n t a x : S i m p l e > R e l a t i v e > A d j e c t i v e A d j e c t i v e > S i m p l e > R e l a t i v e L o c u s o f E m b e d d i n g : No d i f f e r e n c e s R i g h t b r a n c h i n g > S e l f - e m b e d d e d Quantitative Data TASK 1 49 Method S u b j e c t s . The Ss were 20 n a t i v e E n g l i s h s p e a k i n g n u r s e r y s c h o o l c h i l d r e n . Ten S s , f o u r boys and s i x g i r l s , were r u n i n each o f two age g r o u p s . A s s i g n m e n t t o g r o u p s was made o n the b a s i s o f e x i s t i n g n u r s e r y s c h o o l g r o u p i n g s . Group 2-3 Ss r a n g e d i n age f r o m 2 y e a r s 7 months t o 4 y e a r s 1 month . A v e r a g e age was 3 y e a r s 6 mon ths . Group 4-5 Ss r a n g e d i n age f r om 4 y e a r s 6 months t o 5 y e a r s 8 mon ths . A v e r a g e age was 5 y e a r s . A l l Ss a t t e n d e d a n u r s e r y s c h o o l i n B e l l i n g h a m , W a s h i n g t o n . M a t e r i a l s . T a s k 1 c o n s i s t e d o f 36 s e n t e n c e s and 36 s e t s o f f o u r p i c t u r e s i l l u s t r a t i n g t h e s e n t e n c e s . T a s k 1 s e n t e n c e s v a r i e d o n f a c t o r s : S y n t a x , Embeddedness , and P ronoun U s e . The two S yn tax c o n d i t i o n s were R e l a t i v e c l a u s e and S i m p l e . The R e l a t i v e c l a u s e s e n t e n c e s were composed o f a m a i n c l a u s e and one dependent c l a u s e . S i m p l e s e n t e n c e s were a c t u -a l l y p a i r s o f s e n t e n c e s , t h e ma in c l a u s e and dependent c l a u s e o f t h e R e l a t i v e c l a u s e s e n t e n c e s w r i t t e n a s two i n d e p e n d e n t s e n t e n c e s . The S i m p l e s e n t e n c e s , o f t e n r e f e r r e d t o a s k e r n e l s e n t e n c e s I n p s y c h o l l n g u i s -t i c l i t e r a t u r e , were s t r u c t u r a l l y c l o s e r t o t h e u n d e r l y i n g s t r i n g s i n t h a t f ewer t r a n s f o r m a t i o n s s t a n d between t h e S i m p l e s e n t e n c e s and t h e u n d e r l y i n g s t r i n g s t han between R e l a t i v e c l a u s e s e n t e n c e s and t h e u n d e r -l y i n g s t r i n g s . The d e s i g n o f T a s k 1 was an i n c o m p l e t e 2 X 3 X 3 f a c t o r i a l s i n c e Embeddedness a n d P ronoun Use v a r i a b l e s o n l y a p p l i e d t o R e l a t i v e c l a u s e s e n t e n c e s . A S i m p l e s e n t e n c e by d e f i n i t i o n does no t c o n t a i n an embedded s e n t e n c e o r a r e l a t i v e p r o n o u n . A c c o r d i n g l y , o n l y R e l a t i v e c l a u s e s e n -t e n c e s v a r i e d o n t h e two f a c t o r s , Embeddedness and P ronoun U s e . The t h r e e l e v e l s o f Embeddedness were end-embedding by m o d i f i c a t i o n o f t h e 50 substantive of the verbal (V), end-embedding by modification of the ob-ject of the main clause or object of the preposition of the main clause (0) , and self-embedding by modification of the subject of the main clause (S).* The three levels of Pronoun Use were subject (s), object (o), and object of the preposition of the relative clause (p). It was noted l n the presentation of the grammar of the relative clause that the relative pronoun may substitute for any noun in the dependent clause or insert sentence. Although this variable has not previously been investigated and i s of l i t t l e theoretical significance, use of the pronoun may con-tribute to the psychological d i f f i c u l t y of a sentence. If so, this fac-tor should be controlled l n future experiments. An example of each of the nine relative clause sentence types i s presented i n Table 1 with corresponding simple sentences. The set of sentences was constructed by f i r s t generating four ex-amples of each of the nine relative clause sentence types. Each set of four examples was constructed by establishing a sentence frame for each of the nine relative clause types, leaving one noun place in the relative clause empty and one in the main clause. Except for the case of the use of the relative clause to modify the substantive of the verbal ( V . 8 Vo» Vp^» t l i e n 0 u n t o b e ttodi^ied by the relative clause remained cons-tant across the four sentences. The two empty noun slots In each set of four frames were f i l l e d with four nouns (boy, g i r l , box, b a l l ; or dog, cat, box, b a l l ; or boy, g i r l , dog, cat) i n the four possible combina-tions of two. By way of example, Set S , representing self-embedding by modification of the subject of the main clause and use of the pronoun *The term "end-embedding" was used to refer to sentences previously described as right-recursive, e.g., "The boy sees the dog that s i t s on the porch." T a b l e 1 Sample T a s k 1 S en t ences f o r Comprehens ion and I m i t a t i o n P r o c e d u r e s M o d i f i c a t i o n o f s u b s t a n t i v e o f v e r b a l (V) R e l a t i v e p r o n o u n a s s u b j e c t o f c l a u s e R e l a t i v e : T h e r e i s t h e boy who s i t s o n t h e b o x . S i m p l e : T h e r e i s t h e b o y . The b o y s i t s o n t h e b o x . V R e l a t i v e p r o n o u n a s o b j e c t o f c l a u s e o R e l a t i v e : T h e r e i s t h e dog t h a t t h e l i t t l e boy p e t s . S i m p l e : T h e r e i s t h e b o y . The l i t t l e b o y p e t s t h e d o g . V R e l a t i v e p r o n o u n a s o b j e c t o f p r e p o s i t i o n P R e l a t i v e : T h e r e i s t h e box o n w h i c h t h e boy s i t s . S i m p l e : T h e r e i s t h e b o x . The boy s i t s on t h e b o x . M o d i f i c a t i o n o f o b j e c t o r o b j e c t o f p r e p o s i t i o n o f ma in c l a u s e (0) 0^ R e l a t i v e p ronoun a s s u b j e c t o f c l a u s e R e l a t i v e : The boy p e t s t h e dog t h a t s i t s on t h e b o x . S i m p l e : The boy p e t s t h e d o g . The dog s i t s o n the b o x . 0 q R e l a t i v e p ronoun as o b j e c t o f c l a u s e R e l a t i v e : The dog s i t s on t h e box t h a t t h e b o y h o l d s . S i m p l e : The dog s i t s on t h e b o x . The boy h o l d s t h e b o x . 0 R e l a t i v e p ronoun a s o b j e c t o f p r e p o s i t i o n P R e l a t i v e : The boy h o l d s the b a l l o n w h i c h t h e dog s i t s . S i m p l e : The boy h o l d s t he b a l l . The dog s i t s on t h e b a l l . T a b l e 1 ( c o n t i n u e d ) 52 M o d i f i c a t i o n o f s u b j e c t o f ma in c l a u s e (S) S g R e l a t i v e p ronoun a s s u b j e c t o f c l a u s e R e l a t i v e : The g i r l who s i t s on t h e box p e t s t h e d o g . S i m p l e : The g i r l p e t s t h e d o g . The g i r l s i t s o n t h e b o x . S R e l a t i v e p ronoun a s o b j e c t o f c l a u s e 0 R e l a t i v e : The d o g t h a t t h e boy p e t s s i t s o n t h e b o x . S i m p l e : The dog s i t s on t h e b o x . The boy p e t s t h e d o g . S^ R e l a t i v e p r o n o u n a s o b j e c t o f p r e p o s i t i o n R e l a t i v e : T h e g i r l o n whom t h e dog jumps h o l d s t h e b a l l . S i m p l e : The g i r l h o l d s t h e b a l l . The dog jumps o n t h e g i r l . 53 as subject of the relative clause, i s presented belovr. The g i r l who s i t s on the box pets the dog. The g i r l who sit s on the b a l l pets the dog. The g i r l who s i t s on the box pets the cat. The g i r l who s i t s on the b a l l pets the cat. A l l sentences i n the Relative clause condition were nine or ten words in length. The 36 sentences in the Simple structure condition were written from the 36 Relative clause sentences by replacing the relative pronoun with the appropriate noun and writing the two clauses as separate sen-tences. For example, "The g i r l who s i t s on the box pets the dog" became "The g i r l pets the dog. The g i r l s i t s on the box." Two forms of Task 1 were constructed such that each child was pre-sented with 36 sentences, two examples of each of the nine Relative clause types and two examples of each of the Simple structure sentences corresponding to the Relative clause types. Form A and B differed in which two of the four examples of each type were presented in a given condition. Yngve numbers were determined for each word i n each sentence and the mean depth calculated according to the procedure outlined by Martin and Roberts, (1966), To obtain a depth index for each level of Embedded-ness the mean depths for sentences representing each of the Pronoun uses were averaged. The resulting number was referred to as average mean depth. Likewise, to obtain an index for each level of Pronoun use, the mean depths for sentences representing each level of Embeddedness were averaged** The mean depths and average mean depths are presented •^Differential predictions were not discussed in the introduction since the Pronoun Use variable was not of primary Importance. Since addi-tional transformations are not required for any of the three pronoun uses, no differences in d i f f i c u l t y would be predicted from the trans-formation Hypothesis. The Pronoun Use conditions could, however, be ordered i n terms of mean depth. 5 4 i n T a b l e 2. C o r r e s p o n d i n g t o each o f t h e 36 T a s k 1 s e n t e n c e s were a s e t o f f o u r p i c t u r e s . The f o u r p i c t u r e s d e p i c t e d t h e f o u r s e n t e n c e examples o f a g i v e n s e n t e n c e t y p e ( e . g . S ) . The s e n t e n c e was one o f t h e examples s and c o r r e s p o n d e d t o one o f t h e p i c t u r e s . The f o u r p i c t u r e s i n e a c h s e t were i d e n t i c a l e x c e p t f o r t he v a r i a t i o n i n c o m b i n a t i o n o f o b j e c t s and a c t o r s ( e . g . , b a l l - g i r l - c a t o r b o x - g l r l - c a t o r b a l l - g i r l - d o g o r box-g i r l - d o g ) . The p i c t u r e s were b l a c k l i n e d r a w i n g s o n 8 1/2 x 11 I n c h w h i t e p a p e r . Examples a r e p r e s e n t e d i n A p p e n d i x B. The p i c t u r e s were mounted i n two l o o s e - l e a f n o t e b o o k s be tween a s h e e t o f b a c k i n g m a t e r i a l and a t r a n s p a r e n t c o v e r . Two o f t he f o u r p i c t u r e s o f a s e t were mounted s i d e by s i d e i n e a ch no t ebook i n s u c h a way t h a t by t u r n i n g t h e pages s i m u l t a n e o u s l y i n b o t h b o o k s , t h e f o u r p i c t u r e s c o u l d be p r e s e n t e d In c o n j u n c t i o n w i t h a s e n t e n c e c o n t e n t . T h i s a l l o w e d f o r f o u r r e s p o n s e a l t e r n a t i v e s f o r t h e Comprehens ion P r o c e d u r e . E a ch s e t o f f o u r p i c t u r e s o c c u r r e d f o u r t i m e s d u r i n g t h e t a s k . T h e r e was no c o n s i s t e n t r e l a t i o n -s h i p between t h e c o r r e c t r e s p o n s e and p o s i t i o n ( l e f t , r i g h t , t o p , bo t tom) o f t h e p i c t u r e s . No p i c t u r e s were mounted on a l t e r n a t e f a c i n g p a g e s , l e a v i n g t h e b l a c k mount ing p a p e r s h o w i n g . Comprehens ion P r o c e d u r e . E a c h c h i l d was t e s t e d i n d i v i d u a l l y . The S was t o l d t h a t t oday t h e y (E and S) were g o i n g t o l o o k a t some p i c t u r e books and t h a t when t h e r e was a b l a c k page E wou ld t e l l £ t h e name o f one o f t h e p i c t u r e s o n t h e n e x t p a g e . The j> was i n s t r u c t e d t o l i s t e n v e r y c a r e f u l l y , t hen E r e a d a p r a c t i c e s e n t e n c e . A f t e r t h e pages were t u r n e d , t h e £ was t o l d t o p o i n t t o t h e p i c t u r e t h a t matched what E had s a i d . The S was c a u t i o n e d t o be s u r e and l o o k a t a l l f o u r p i c t u r e s and t h e n t o u c h t h e p i c t u r e as soon a s he had d e c i d e d x*hich one went w i t h what E had s a i d . O n l y t he one p r a c t i c e p r o b l e m u s e d i n t h e i n s t r u c t i o n s 55 T a b l e 2 Ave rage Mean Depth f o r S en t ences R e p r e s e n t i n g each S y n t a x , Embeddedness and P ronoun Use C o n d i t i o n on T a s k 1 Syn tax Embeddedness S imp l e R e l a t i v e A v e r a g e Mean Depth—Embeddedness V 1.00 1.11 1.06 0 1.09 1.20 1.15 S 1.09 1.53 1.31 A v e r a g e Mean D e p t h — S y n t a x 1.06 1.28 P ronoun Use A v e r a g e Mean D e p t h — P r o n o u n Use (s ) 1 .00 1.20 1.10 (P) 1.06 1.30 1.18 (o) 1.06 1.34 1 .20 A v e r a g e Mean D e p t h — S y n t a x 1.04 1 .28 56 was necessary. The E proceeded to read each sentence aloud when a black page was showing and then to turn the pages to reveal each set of pic-tures. Sentences and pictures were presented in a predetermined random order. Each sentence was read only once except in cases where Interup-tions occurred or the child was not attending. One repetition was given under these circumstances. The 36 sentences were presented in one of two random orders, Form A or Form B. Half of the Ss i n each age group received each form. The pictures were ordered to match the random order of the sentences. Sub-jects receiving Form B of the Task began at the end of the picture books since the sentences were in reverse order of Form A. The S/s choice of pictures for each sentence and latency of response were recorded. Latency was defined as the amount of time between E's turning of the page to reveal the pictures and the child's pointing re-sponse. The E started a stopwatch as turning of the pages was completed and stopped the watch when S indicated his choice by pointing. Imitation Procedure. In the Imitation procedure no pictures were used. At the beginning of the session the child was told that today they would play an imitation game and was asked i f he knew what an Imi-tation game was. The E explained that she would say a sentence and that S_was to say just what E said. An example was given and the child was asked to repeat i t . The E proceeded with the task i f S responded appro-priately. If S did not respond correctly, E repeated the instructions to "Say just what I say," and repeated the example. The JE read each sentence aloud once and waited for a response. If S gave no response, E asked, " T e l l me just what you remember. Can you do that?" If the child failed to respond, a second reading of the sen-tence was given. Failures to respond were usually due to restlessness, 57 direct evasion, or interruptions. Sentences were read in a predetermined random order, Form A or B. Ss receiving Form A on the Comprehension procedure were given Form B on the Imitation procedure, and vice versa. A tape recording of E's read-ing of the sentences and the S/s imitations was made. Written protocols were later made from the tapes. The Ss were allowed to color pictures provided by E or put together familiar puzzles during the Imitation procedure. The E administered items as the child played, prefacing items with "Can you say this now?" or "Let's try another one now" i f JJ's attention had strayed. This technique of letting Ss play with puzzles or color considerably increased the number of items children were able to complete in a single session. This technique was not continued with a couple of young SB who demon-strated quickly that playing during the task was too distracting. In-stead, these children were given periodic play sessions. 58 R e s u l t s and D i s c u s s i o n Comprehens ion Age and S y n t a x . The mean number o f c o r r e c t l y comprehended R e l a t i v e c l a u s e and S i m p l e s e n t e n c e s f o r e a ch age g roup Is p l o t t e d i n F i g 1. The r e s u l t s o f a t w o - f a c t o r a n a l y s i s o f v a r i a n c e f o r Age (A) and Syntax (B ) , w i t h r e p e a t e d measures on 3, a r e summar ized i n T a b l e 3. Age was f o u n d t o be a s i g n i f i c a n t f a c t o r . Group 2-3 s c o r e d a mean o f 23 .2 (64%) c o r r e c t and Group 4-5 a mean o f 30 .4 (84%) c o r r e c t , w e l l above chance l e v e l (25%) . The Syn tax ma in e f f e c t and Age X Syn tax i n t e r a c t i o n d i d n o t r e a c h s i g n i f i c a n c e , f a i l i n g t o s u p p o r t t h e e x p e c t a t i o n t h a t R e l a -t i v e c l a u s e s e n t e n c e s wou ld be more d i f f i c u l t t o comprehend t h a n S i m p l e f o r a l l S s , b u t t h a t t he e f f e c t wou ld be c o n s i d e r a b l y g r e a t e r f o r t h e younge r S s . T h i s r e l a t i o n s h i p was p r e d i c t e d i n d i r e c t l y f rom b o t h the T r a n s f o r m a t i o n a l and Dep th h y p o t h e s e s . T h a t i s , b o t h h y p o t h e s e s s t a t e t h a t the g r e a t e r t h e memory r e q u i r e m e n t s o f a s e n t e n c e ( Indexed i n te rms o f t r a n s f o r m a t i o n s o r d e p t h ) , t h e p o o r e r wou ld be p e r f o r m a n c e . S i n c e memory c a p a c i t y i n c r e a s e s w i t h age (Munn, 1 9 5 4 ) , i t f o l l o w s t h a t a n y t h i n g t h a t p l a c e s a d d i t i o n a l demands on t h e c h i l d ' s memory ( t r a n s -f o r m a t i o n s o r dep th ) w i l l r e s u l t I n c o r r e s p o n d i n g l y p o o r e r p e r f o r m a n c e . C o u p l i n g memory demands o f R e l a t i v e c l a u s e s e n t e n c e s w i t h t h e p o s s i b i l i t y o f l a c k o f knowledge o f t h e R e l a t i v e c l a u s e s t r u c t u r e , Group 2-3 p e r -fo rmance o n R e l a t i v e c l a u s e s e n t e n c e s was e x p e c t e d t o b e m a r k e d l y d e -p r e s s e d compared w i t h p e r f o r m a n c e on S i m p l e s e n t e n c e s . The a b s e n c e o f a S yn tax e f f e c t o r i n t e r a c t i o n s u g g e s t s (1) t h a t a l l t h e Ss p o s s e s s e d a t l e a s t r u d i m e n t a r y knowledge o f t h e r e l a t i v e c l a u s e s t r u c t u r e , age d i f f e r e n c e s s i m p l y r e f l e c t i n g memory d i f f e r e n c e s , o r (2) t h a t Ss were a b l e t o r e s p o n d c o r r e c t l y i r r e s p e c t i v e o f t h e 16 F i g . 1 Mean number o f c o r r e c t r e s p o n s e s on T a s k 1 Comprehens ion P r o c e d u r e f o r R e l a t i v e and S i m p l e s e n -t e n c e s a s a f u n c t i o n o f a g e . 60 Table 3 Summary o f A n a l y s i s o f V a r i a n c e o f C o r r e c t Comprehens ion Responses f o r Two Age Groups (A) Taken as Repea ted Measures on Syn tax (B) Sou r ce d f MS F P Between S u b j e c t s 19 Age (A) 1 1 2 9 . 6 0 1 2 . 2 7 .01 S u b j e c t s W i t h i n Groups 18 1 0 . 5 6 W i t h i n S u b j e c t s 20 Syn tax (B) 1 3 .60 3 .10 NS AB 1 1.60 1.38 NS R e s i d u a l 18 1.16 61 s t r u c t u r e o f t h e s e n t e n c e o f t h e b a s i s o f noun c o n t e n t , younge r Ss p e r -f o r m i n g p o o r e r s i m p l y b e c a u s e t h e y c o u l d no t r e c a l l t h e two o r t h r e e n o u n c o n t e n t s . N e i t h e r p o s s i b i l i t y c a n be r u l e d ou t t a k i n g o n l y c o m p r e -h e n s i o n d a t a i n t o c o n s i d e r a t i o n . Embeddedness and P ronoun U s e . T h e r e a r e some p rob l ems a s s o c i a t e d w i t h t h e a n a l y s i s o f t h e Embeddedness and P ronoun Use f a c t o r s w h i c h must be c l a r i f i e d . F i r s t , i t s h o u l d be p o i n t e d ou t t h a t Embeddedness and P ronoun Use a r e b o t h con founded w i t h i t e m e f f e c t s . Tha t i s , the c o n t e n t o f t h e i t e m s was s i m i l a r b u t n o t i d e n t i c a l unde r each Embeddedness and unde r e a ch P ronoun Use c o n d i t i o n (See T a b l e 1 ) . S e c o n d , i t was n o t p o s s i b l e t o o b t a i n a m e a n i n g f u l Embeddedness o r P ronoun Use ma in e f f e c t s i m p l y by c o l l a s p i n g o v e r t h e S i m p l e and R e l a t i v e f a c t o r s s i n c e S i m p l e s e n t e n c e s b y d e f i n i t i o n do n o t c o n t a i n embedded s e n t e n c e s o r r e l a t i v e . p r o n o u n s . These p rob l ems r e q u i r e d (1) t h a t s e p a r a t e a n a l y s e s b e p e r -fo rmed o n S i m p l e and R e l a t i v e s e n t e n c e s t o d e t e r m i n e t h e e f f e c t s o f Embeddedness o r P ronoun Use m a n i p u l a t i o n s , and (2 ) t h a t c o m p a r i s o n s o f R e l a t i v e and S i m p l e means t h e n be made f o r each Embeddedness and P r o -noun Use t r e a t m e n t . * * I t was e x p e c t e d t h a t Ss m i g h t p e r f o r m d i f f e r e n t l y on t h e s e t s o f S i m p l e s e n t e n c e s b e c a u s e o f d i f f e r e n c e s i n i t e m c o n t e n t . I f i t e m e f f e c t s were f o u n d by a n a l y s i s o f t he S i m p l e d a t a , i t wou ld be n e c e s s a r y t o compare S i m p l e and R e l a t i v e means on each Embeddedness and P ronoun c o n d i t i o n t o i s o l a t e Embeddedness and P ronoun Use t r e a t e m e n t e f f e c t s . I n o t h e r w o r d s , Embeddedness, o r P ronoun e f f e c t s f o r S i m p l e d a t a were c o n s i d e r e d e v i d e n c e o f I tem e f f e c t s , w h i l e Embeddedness o r P ronoun e f f e c t s f o r R e l a t i v e d a t a x/ere c o n s i d e r e d a c o n f o u n d i n g o f i t e m and t r e a t m e n t e f f e c t s . A d i f f e r e n c e between S i m p l e and R e l a t i v e Embeddedness S means ( R e l a t i v e p o o r e r t han S i m p l e ) wou ld b e i n t e r p r e t e d a s i n d i c a t i n g a t r e a t -ment e f f e c t . F o r examp l e , i f i t were f o u n d t h a t p e r f o r m a n c e o n Embedded c o n d i t i o n S were s i g n i f i c a n t l y p o o r e r t han V o r 0 , i n o r d e r t o c o n c l u d e t h a t t h e d i f f e r e n c e s were due t o t r e a t m e n t and no t s i m p l y an i t e m e f f e c t i t wou ld be n e c e s s a r y t o compare S R e l a t i v e c l a u s e i t e m s w i t h S S i m p l e i t e m s . I n e f f e c t , t h e a s s u m p t i o n was made t h a t [ ( I t em + T r e a t -ment) - I tem « T r e a t m e n t . ] T h i s a s s u m p t i o n was made f o r a n a l y s i s o f Embeddedness on T a s k 1 and 2 Comprehens ion and I m i t a t i o n P r o c e d u r e s and f o r a n a l y s i s o f P ronoun U s e on T a s k 1 Comprehens ion and I m i t a t i o n P r o -c e d u r e s . 62 A t h r e e - f a c t o r a n a l y s i s o f v a r i a n c e f o r Age ( A ) , Embeddedness C 8 ) and P ronoun Use ( C ) , w i t h r e p e a t e d measures o n B and C , was p e r f o r m e d o n R e l a t i v e c l a u s e d a t a . The r e s u l t s o f t h e a n a l y s i s a r e summar ized i n T a b l e 4 . The A g e , Embeddedness and P ronoun Use ma in e f f e c t s were a l l s i g n i f i c a n t . A Neuman-Keuls S e q u e n t i a l Range T e s t (W ine r , 1962) was u s e d t o d i s c o v e r t h e s o u r c e o f t h e Embeddedness e f f e c t . A V > 0 > S o r d e r i n g o f R e l a t i v e means was f o u n d (p_ < .01 f o r a l l c o m p a r i s o n s ) . The mean number o f c o r r e c t l y comprehended R e l a t i v e c l a u s e s e n t e n c e s i s p l o t t e d i n F i g . 2 as a f u n c t i o n o f Embeddedness . The Embeddedness c o n d i t i o n s , V , 0 and S, r e p r e s e n t e d o n t h e a b c i s s a a r e o r d e r e d f r om low t o h i g h a v e r a g e mean d e p t h , r e a d i n g l e f t t o r i g h t . The o b t a i n e d o r d e r i n g o f means was c o n s i s -t e n t w i t h t h e o r d e r i n g p r e d i c t e d f r o m t h e a v e r a g e mean d e p t h i n d i c e s b u t was i n c o n s i s t e n t w i t h t h e V * 0 «* S o r d e r i n g p r e d i c t e d f r om t h e T r a n s f o r m a t i o n H y p o t h e s i s * The Heuman-Keuls T e s t was a l s o u s e d t o d e t e r m i n e the s o u r c e o f t he P ronoun Use e f f e c t . A ( s ) « (o) > (p ) o r d e r i n g o f means was f o u n d [p_<.01 f o r (p) v s (o) and (p) v s ( s ) . ] . The mean number o f c o r r e c t l y comprehended R e l a t i v e c l a u s e s e n t e n c e s as a f u n c t i o n o f P ronoun Use i s p l o t t e d i n F i g . 3. The o b t a i n e d o r d e r i n g was i n c o n s i s t e n t w i t h b o t h t h e no d i f f e r e n c e p r e d i c t i o n f r om the T r a n s f o r m a t i o n H y p o t h e s i s and t h e ( s ) > (p ) > (o ) o r d e r i n g p r e d i c t e d f r om t h e Dep th H y p o t h e s i s . A l t h o u g h Embeddedness and P ronoun Use e f f e c t s were f o u n d f o r R e l a -t i v e i t e m s , d a t a on comparab le S i m p l e p a i r s o f s e n t e n c e s must be p r e s e n t e d b e f o r e any c o n c l u s i o n s abou t t r e a t m e n t e f f e c t s c a n be made. The o b t a i n e d d i f f e r e n c e s may s i m p l y be due t o i t e m e f f e c t s . The r e s u l t s o f t h e a n a l y -s i s o f v a r i a n c e o n S i m p l e d a t a a r e summar ized i n T a b l e 5. O n l y t h e Age and Embeddedness ma in e f f e c t s r e a c h e d s i g n i f i c a n c e , Group 2-3 .Ss 63 T a b l e 4 Summary o f A n a l y s i s o f V a r i a n c e o f C o r r e c t Comprehens ion Responses o n R e l a t i v e Sen t ences f o r Two Age Groups (A) Taken as Repea ted Measu res on Embeddedness (B) and P ronoun Use (C) Sou r ce d f MS F P Between S u b j e c t s 19 Age (A) 1 8 .88 11 .68 .01 S u b j e c t s W i t h i n G roups 18 . 7 6 W i t h i n S u b j e c t s 160 Embeddedness (B) 2 3.04 1 0 . 4 3 .01 P ronoun Use (C) 2 .91 3.14 .05 AB 2 . 58 2 .00 NS AC 2 .11 -BC 4 . 0 9 -ABC 4 .59 2 .03 NS R e s i d u a l 144 .29 64 6 r 5 -• RELATIVE O S IMPLE • GROUP 4 - 5 (SOLID) • GROUP 2-3 (OPEN) V 0 E M B E D D E D N E S S F i g . 2. Mean number o f c o r r e c t r e s p o n s e s on T a s k 1 Comprehens ion P r o c e d u r e f o r R e l a t i v e and S i m p l e c o n t r o l s e n t e n c e s as a f u n c t i o n o f Embeddedness . 65 6r • RELATIVE O SIMPLE • GROUP 4-5 (SOLID) • GROUP 2-3 (OPEN) 0 S P P R O N O U N U S E P i g . 3. Mean number o f c o r r e c t r e s p o n s e s on T a s k 1 Comprehens ion P r o c e d u r e f o r R e l a t i v e and S i m p l e c o n t r o l s e n t e n c e s as a f u n c t i o n o f P ronoun U s e . 66 T a b l e 5 Summary o f A n a l y s i s o f V a r i a n c e o f C o r r e c t Comprehens ion Responses on S i m p l e Sen t ences f o r Two Age Groups (A) Taken a s Repea ted Measu res on Embeddedness (B) and P ronoun Use (C) S o u r c e d f MS F P Between S u b j e c t s 19 Age (A) 1 5 .69 10 .54 .01 S u b j e c t s W i t h i n G roups 18 .54 W i t h i n Groups 160 Embeddedness (B) 2 4 .41 1 4 . 7 0 .01 P ronoun Use (C) 2 . 07 -AB 2 .51 1.70 NS AC 2 .27 -BC 4 . 2 9 -ABC 4 .29 -R e s i d u a l 144 .30 67 p e r f o r m i n g p o o r e r t h a n Group 4-5 . A Neuman-Keuls T e s t was p e r f o r m e d t o d i s c o v e r t h e s o u r c e o f t h e Embeddedness e f f e c t . The same V > 0 > S o r -d e r i n g o f means a s f o u n d f o r R e l a t i v e s e n t e n c e s was o b t a i n e d (p_< .01 f o r a l l c o m p a r i s o n s ) . The mean number o f c o r r e c t l y comprehended S i m p l e s e n t e n c e s p l o t t e d a s a f u n c t i o n o f Embeddedness i s p r e s e n t e d i n F i g . 2 . The t h r e e Embeddedness c o n d i t i o n s o n t h e a b c i s s a r e p r e s e n t t h r e e d i f f e r -e n t s e t s o f i t e m s f o r S i m p l e s e n t e n c e s r a t h e r t han Embeddedness t r e a t -men t s . S i m p l e s e n t e n c e s by d e f i n i t i o n do n o t c o n t a i n a n embedded s e n -t e n c e . Each s e t c o r r e s p o n d s s e m a n t i c a l l y t o t h e R e l a t i v e c l a u s e s e n -t e n c e s w i t h i n e a c h Embeddedness c o n d i t i o n . F u r t h e r a n a l y s i s was r e q u i r e d t o d e t e r m i n e i f t h e V > 0 > S o r d e r i n g o f means f o r t he R e l a t i v e s e n t e n c e s was a t r u e Embeddedness t r e a t m e n t e f f e c t o r a f u n c t i o n o f i t e m d i f f e r e n c e s , p a r t i c u l a r l y s i n c e t h e o r d e r i n g f o r R e l a t i v e and S i m p l e means was t h e same. T h r e e t w o - f a c t o r a n a l y s e s o f v a r i a n c e f o r Age (A) and Syn tax ( 8 ) , w i t h r e p e a t e d measures o n the l a t t e r , were p e r f o r m e d , each a n a l y s i s compar ing p e r f o r m a n c e o n one t y p e o f Embeddedness (V, 0 o r S ) . A s i g n i f i c a n t S yn tax d i f f e r e n c e ( S imp l e > R e l a t i v e ) was n e c e s s a r y t o I n t e r p r e t an Embeddedness e f f e c t f o r R e l a t i v e s e n t e n c e s as due to t r e a t m e n t , n o t i t e m e f f e c t s . The r e s u l t s o f the t h r e e a n a l y s e s a r e summar ized i n T a b l e 6 . A s i g n i f i c a n t S yn tax e f f e c t was f o u n d f o r Embeddedness c o n d i t i o n V o n l y , p e r f o r m a n c e b e i n g p o o r e r on R e l a t i v e s e n t e n c e s t h a n o n S i m p l e , p a r t i c u -l a r l y f o r Group 2-3. The absence o f a S yn tax e f f e c t f o r t h e 0 and S Embeddedness c o n d i t i o n s I n d i c a t e s t h a t t he V > 0 > S o r d e r i n g o f Embedded-n e s s means o b t a i n e d f o r R e l a t i v e s e n t e n c e s ( T a b l e 4) i s a t t r i b u t a b l e t o i t e m e f f e c t s , n o t t h e Embeddedness t r e a t m e n t . The a b s e n c e o f d i f f e r e n c e s a t t r i b u t a b l e t o Embeddedness i s c o n s i s -t e n t w i t h t h e T r a n s f o r m a t i o n a l H y p o t h e s i s b u t i n c o n s i s t e n t w i t h t h e mean 68 T a b l e 6 Summary o f T h r e e A n a l y s e s o f V a r i a n c e o f C o r r e c t Comprehens ion Responses by Group 2-3 on Embeddedness C o n d i t i o n s V , 0 and S f o r Age (A) and S yn t ax (B) Taken as Repea ted Measu res o n B Embeddedness C o n d i t i o n S o u r c e d f M S Between S u b j e c t s 19 Age (A) 1 4 . 9 0 4 . 7 6 NS S u b j e c t s W i t h i n G roups 18 1.03 W i t h i n S u b j e c t s 60 S yn t ax (B) 1 1 .60 2 2 . 8 6 .01 AB 1 . 4 0 5.71 .05 R e s i d u a l 58 . 0 7 Between S u b j e c t s 19 Age (A) 1 1 8 . 2 3 7 .35 .05 S u b j e c t s W i t h i n Groups 18 2 .48 W i t h i n S u b j e c t s 60 S yn tax (B) 1 . 0 3 AB 1 .61 1.49 NS R e s i d u a l 58 .41 T a b l e 6 ( c o n t i n u e d ) 69 Between S u b j e c t s 1? Age (A) 1 24 .02 1 2 . 1 9 . 01 S u b j e c t s W i t h i n G roups 18 1 .97 W i t h i n S u b j e c t s 60 S y n t a x (B) 1 .22 AB 1 2 . 0 3 2 .11 NS R e s i d u a l 58 . 96 7 0 d e p t h o r d e r i n g . A p r e d i c t i o n o f no d i f f e r e n c e between Embeddedness c o n -d i t i o n s f r o m the T r a n s f o r m a t i o n a l H y p o t h e s i s was made b e c a u s e d e r i v a t i o n -a l l y t h e t h r e e t y p e s o f R e l a t i v e c l a u s e s e n t e n c e s do n o t d i f f e r , i . e . , t h e number and k i n d o f t r a n s f o r m a t i o n s i n v o l v e d l n t h e d e r i v a t i o n s a r e i d e n t i c a l f o r an end-embedded and a s e l f - embedded s e n t e n c e . H e n c e , t h e i n d e x o f d i f f i c u l t y ba sed upon the number o f t r a n s f o r m a t i o n s was t h e same f o r each Embeddedness t y p e . The f a i l u r e o f t h e d e p t h i n d i c e s t o o r d e r t h e means may b e o f c o n s i d e r a b l e s i g n i f i c a n c e f o r a mode l o f p e r -f o r m a n c e . I t was assumed l n t h e d i s c u s s i o n o f t h e Yngve Depth H y p o t h e s i s t h a t t h e p r o d u c t i o n mode l c o u l d be a p p l i e d to c o m p r e h e n s i o n , a l t h o u g h comprehens ion p e r f o r m a n c e i n g e n e r a l may b e ahead o f p r o d u c t i o n . T h a t i s , i t was assumed t h a t t he same v a r i a b l e s y i e l d i n g h i g h mean dep ths t h a t i n f l u e n c e p r o d u c t i o n wou ld a l s o i n f l u e n c e c o m p r e h e n s i o n . A t l e a s t two i n t e r p r e t a t i o n s o f t h e a b s e n c e o f d i f f e r e n c e s a r e p o s s i b l e . (1 ) t h e s e n t e n c e s were e i t h e r a l l t o o d i f f i c u l t o r easy to a l l o w f o r d i f f e r -e n t i a t i o n i n p e r f o r m a n c e ; o r (2) t he Dep th H y p o t h e s i s a s f o r m u l a t e d by Yngve c a n n o t be g e n e r a l i z e d t o c o v e r comprehens ion as w e l l a s p r o d u c -t i o n . The r e s u l t s do n o t a l l o w f o r e l i m i n a t i o n o f e i t h e r p o s s i b i l i t y , even when c o n s i d e r e d i n l i g h t o f o t h e r s t u d i e s . Gae r (1969) a l s o f o u n d t h a t l o c u s o f embedding was n o t a s i g n i f i c a n t f a c t o r i n comprehens ion o f r e l a t i v e c l a u s e s e n t e n c e s w i t h c h i l d r e n between t h r e e and s i x y e a r s o f a g e . To d e t e r m i n e whe the r t he o b t a i n e d (s ) • (o) > (p) o r d e r i n g o f P r o -noun U s e means f o r R e l a t i v e i t e m s was due t o t he P ronoun Use t r e a t m e n t o r i t e m e f f e c t , two t w o - f a c t o r a n a l y s e s o f v a r i a n c e were p e r f o r m e d f o r Age (A) and Syn tax ( B ) , w i t h r e p e a t e d measures on t h e l a t t e r . An a n a l y -s i s was n o t p e r f o r m e d f o r P ronoun Use ( s ) s i n c e t he means f o r R e l a t i v e and S i m p l e i t e m s were i d e n t i c a l (See F i g . 3 ) . As f o r Embeddedness , a 71 s i g n i f i c a n t S yn t ax d i f f e r e n c e ( S i m p l e > R e l a t i v e ) was n e c e s s a r y t o i n t e r -p r e t a P ronoun Use e f f e c t f o r R e l a t i v e s e n t e n c e s as due t o t r e a t m e n t , n o t i t e m e f f e c t s . The r e s u l t s o f t h e a n a l y s e s a r e summar ized i n T a b l e 7. A s i g n i f i c a n t S yn t ax e f f e c t was f o u n d o n l y f o r P ronoun Use ( p ) , p e r f o r -mance on R e l a t i v e s e n t e n c e s b e i n g p o o r e r t han on S i m p l e . A s i g n i f i c a n t Age X S yn tax i n t e r a c t i o n , howeve r , was o b t a i n e d f o r P ronoun Use ( o ) . I n s p e c t i o n o f means (See F i g . 3) i n d i c a t e d t h a t Group 4-5 Ss p e r f o r m e d b e t t e r on R e l a t i v e s e n t e n c e s t h a n S i m p l e , w h i l e Group 2-3 Ss p e r f o r m e d p o o r e r on R e l a t i v e s e n t e n c e s . These r e s u l t s , i n p a r t i c u l a r t h e Syntax e f f e c t f o r ( o ) , s u g g e s t t h a t t h e o b t a i n e d (s ) » ( o ) > (p) o r d e r i n g o f means f o r R e l a t i v e s e n t e n c e s may be a t t r i b u t a b l e t o P ronoun Use t r e a t m e n t , n o t s i m p l y i t e m d i f f e r e n c e s . T h i s f i n d i n g i s i n c o n s i s t e n t w i t h t h e p r e d i c -t i o n s f r o m b o t h h y p o t h e s e s . The p o o r e r comprehens i on o f s e n t e n c e s i n w h i c h the p ronoun s e r v e d as t h e o b j e c t o f t h e p r e p o s i t i o n ( e . g . , " T h e g i r l s e e s t he box o n w h i c h t h e dog s i t s " ) p r o b a b l y c o u l d be t r a c e d t o t h e i n f r e q u e n t use o f t h i s f o r m a l l y c o r r e c t s t r u c t u r e . I n s p e e c h , g e n -e r a l l y , t h e c o n v e n t i o n o f n o t e n d i n g a s e n t e n c e w i t h a p r e p o s i t i o n i s n o t f o l l o w e d . I n f a c t , most a d u l t s who h e a r d o r r e a d t h e (o) s e n t e n c e s u s e d In t h e e x p e r i m e n t commented on t h e i r " s t r a n g e n e s s . " Comprehens ion L a t e n c y D a t a . Even i f t he t o t a l c o r r e c t measure were n o t s e n s i t i v e t o t h e i n f l u e n c e o f S yn t ax on Comprehens ion p e r f o r m a n c e , i t wou ld b e e x p e c t e d t h a t t h e amount o f t ime r e q u i r e d t o d e c i d e wh i ch p i c t u r e went w i t h the p r e s e n t e d s e n t e n c e wou ld r e f l e c t t h e g r e a t e r p r o -c e s s i n g r e q u i r e m e n t s o f R e l a t i v e s e n t e n c e s . I n o t h e r w o r d s , i f a s e n -t e n c e r e q u i r e s s e v e r a l t r a n s f o r m a t i o n a l o p e r a t i o n s i n i t s d e r i v a t i o n , more p s y c h o l o g i c a l o p e r a t i o n s s h o u l d be r e q u i r e d t o u n d e r s t a n d o r p r o -duce t h e s e n t e n c e t han a l e s s complex s e n t e n c e . Assuming t h a t a d d i t i o n a l o p e r a t i o n s r e q u i r e more t i m e , t h e l a t e n c y o f r e s p o n s e s h o u l d b e l o n g e r 72 T a b l e 7 Summary o f Two A n a l y s e s o f V a r i a n c e o f C o r r e c t Comprehens ion Responses b y Group 2-3 o n P ronoun Uses (o) and (p) f o r Age (A) and Syn tax (B) T aken a s Repea ted Measu res o n B P ronoun U s e C o n d i t i o n Sou r ce d f MS (o ) (P) Between S u b j e c t s 19 Age (A) 1 1 2 . 1 0 A . 7 6 .05 S u b j e c t s W i t h i n G roups 18 2 .54 W i t h i n S u b j e c t s 60 S yn tax (B) 1 , 1 0 AB 1 2 .50 1 2 . 5 0 .01 R e s i d u a l 58 . 2 0 Between S u b j e c t s 19 Age (A) 1 1 4 . 4 0 8 .94 .01 S u b j e c t s W i t h i n Groups 18 1.61 W i t h i n S u b j e c t s 60 Syn tax (B) 1 2 . 5 0 1 7 . 8 6 .01 AB 1 . 1 0 -R e s i d u a l 58 .14 f o r t h e more complex s e n t e n c e s . S p e c i f i c a l l y , more t ime s h o u l d be r e -q u i r e d t o comprehend R e l a t i v e c l a u s e s e n t e n c e s t h a n S i m p l e s e n t e n c e s f o r a l l S s , a l t h o u g h t h e e f f e c t may be g r e a t e r f o r younge r Ss. D a t a f o r two S s , one f r om e a c h age g r o u p , were e l i m i n a t e d f r om t h e l a t e n c y a n a l y s i s . T h e s e Ss r e a c t i o n p a t t e r n s d i d n o t a l l o w f o r a c c u r a t e l a t e n c y measu remen t . * I t s h o u l d be n o t e d t h a t t h e s e two Ss m e r e l y r e -p r e s e n t e d t h e ex t reme c a s e s . A c c u r a t e l a t e n c y measurement was d i f f i c u l t o n most o f t h e c h i l d r e n . Many o f t h e Ss o f t h e age t e s t e d were t o o d i s -t r a c t a b l e and i n c o n s i s t e n t i n t h e i r manner o f r e s p o n s e t o p r o v i d e r e l i -a b l e l a t e n c i e s . The r e s u l t was g r e a t v a r i a b i l i t y w i t h i n S s . A S ' s l o n g e s t and s h o r t e s t l a t e n c i e s somet imes o c c u r r e d on i t ems w h i c h were examples o f t h e same e x p e r i m e n t a l c o n d i t i o n , d i f f e r i n g o n l y i n one w o r d . I n summary, i n t e r p r e t a t i o n o f t h e l a t e n c y d a t a must be made w i t h c a u t i o n . The mean l a t e n c y o f r e s p o n s e f o r each Syn tax c o n d i t i o n f o r t h e two age g r o u p s i n p r e s e n t e d i n F i g . 4 . Because o f t h e q u e s t i o n a b l e s t a b i l i t y o f t h e d a t a , l a t e n c i e s were c o l l a p s e d o v e r t h e Embeddedness and P ronoun Use c o n d i t i o n s , t h e r e s u l t b e i n g t h a t each Ss s c o r e i s an a v e r a g e o f 18 s c o r e s . A t w o - f a c t o r a n a l y s i s o f v a r i a n c e f o r Age (A) and Syn tax ( B ) , w i t h r e p e a t e d measures on B, was p e r f o r m e d o n mean l a t e n c i e s . The r e -s u l t s a r e summar ized i n T a b l e 8 . O n l y S yn tax was f o u n d t o be a s i g n i f i -c a n t f a c t o r , w i t h l o n g e r l a t e n c i e s on R e l a t i v e s e n t e n c e s t h a n on S i m p l e . T h e s e r e s u l t s a r e i n agreement w i t h t h e n o t i o n p r o p o s e d by M i l l e r (1962) and s u p p o r t e d by o t h e r s ( e . g . , Gough , 1965 ; S l o b i n , 1966> t h a t s t r u c t u r -a l l y complex s e n t e n c e s r e q u i r e a d d i t i o n a l p r o c e s s i n g t ime ( i r r e s p e c t i v e o f a g e ) * The f i n d i n g s , however , do no t d i s t i n g u i s h between t h e Depth * T h e s e two Ss d i d n o t s i m p l y r e s p o n d t o t h e s e n t e n c e s by p o i n t i n g as i n s t r u c t e d b u t engaged i n e x c e s s i v e p r e - c h o i c e v o c a l i z a t i o n s o r o t h e r i n t e r v e n i n g a c t i v i t i e s . 74 T a b l e 8 Summary o f A n a l y s i s o f V a r i a n c e o f L a t e n c y o f Comprehens ion Responses f o r Two Age Groups (A) Taken as Repea ted Measu res on Syn tax (B) S o u r c e d f MS F P Between S u b j e c t s 17 Age (A) 1 2 .93 S u b j e c t s W i t h i n Groups 16 173 .30 W i t h i n S u b j e c t s 18 S yn tax (B) 1 97 .52 1 6 . 1 7 .01 AB 1 10 .82 1.79 NS R e s i d u a l 16 6 .03 75 F i g . 4 . Mean l a t e n c y o f r e s p o n s e on T a s k 1 Compre -h e n s i o n P r o c e d u r e f o r R e l a t i v e and S i m p l e s e n t e n c e s as a f u n c t i o n o f a g e . 76 H y p o t h e s i s and t h e T r a n s f o r m a t i o n H y p o t h e s i s s i n c e t h e y wou ld b e p r e d i c -t e d o n t h e b a s i s o f b o t h m o d e l s . Comprehens ion E r r o r A n a l y s i s . T h e r e were f o u r r e s p o n s e a l t e r n a t i v e s on each t r i a l , o n l y one o f w h i c h was i n one t o one c o r r e s p o n d e n c e w i t h the p r e s e n t e d s e n t e n c e . T h i s p i c t u r e a l t e r n a t i v e was t h e c o r r e c t c h o i c e . The m a i n c l a u s e o r r e l a t i v e c l a u s e c o n t e n t was . however , r e p r e s e n t e d i n two o f t h e o t h e r p i c t u r e s , mean ing t h a t a c h i l d m igh t choose an a l t e r -n a t i v e w h i c h was c o r r e c t w i t h r e s p e c t t o r e l a t i v e c l a u s e c o n t e n t b u t i n c o r r e c t f o r ma in c l a u s e c o n t e n t and v i c e v e r s a . The f o u r t h p i c t u r e a l t e r n a t i v e c o r r e s p o n d e d t o n e i t h e r t h e ma in c l a u s e o r r e l a t i v e c l a u s e c o n t e n t o f t h e p r e s e n t e d s e n t e n c e . A c c o r d i n g l y , i n c o r r e c t r e s p o n s e s were c a t e g o r i z e d a s f o l l o w s : (a) H The p i c t u r e c h o s e n b y S. was c o r r e c t w i t h r e s p e c t t o r e l a t i v e c l a u s e c o n t e n t , b u t i n e r r o r f o r ma in c l a u s e c o n t e n t . F o r examp le , t h e c h o i c e o f a p i c t u r e o f a g i r l p e t t i n g a dog t h a t s i t s on a box wou ld be an M e r r o r f o r t he s e n t e n c e " T h e boy p e t s t he dog t h a t s i t s on t h e b o x . " (b) R The p i c t u r e chosen by S was c o r r e c t w i t h r e s p e c t t o m a i n c l a u s e c o n t e n t b u t i n e r r o r f o r r e l a t i v e c l a u s e c o n t e n t . F o r examp l e , t h e c h o i c e o f a p i c t u r e o f a boy p e t t i n g a dog t h a t s i t s on a b a l l wou ld be an R e r r o r f o r t he s e n t e n c e " T h e boy p e t s t h e dog t h a t s i t s on t h e b o x . " (c ) R-M The p i c t u r e c h o s e n b y S. was c o r r e c t f o r n e i t h e r m a i n n o r r e l a t i v e c l a u s e c o n t e n t . F o r examp le , t h e c h o i c e o f a p i c t u r e o f a g i r l p e t t i n g a dog t h a t s i t s o n a b a l l wou ld be an R-M e r r o r f o r t h e s e n t e n c e " T h e boy p e t s t h e dog t h a t s i t s on t h e b o x . " I t was e x p e c t e d t h a t i f i n c o r r e c t r e s p o n s e s were g u e s s e s , an e q u a l number o f e r r o r s wou ld b e made i n each o f t h e s e c a t e g o r i e s . I f , how-e v e r , Ss c o n s i s t e n t l y p r o c e s s e d a p a r t i c u l a r component o f t he s e n t e n c e s , f o r examp le , t he ma in c l a u s e o n l y o r t h e l a s t few words o f t h e s e n t e n c e , t h e p r o p o r t i o n o f e r r o r s i n each o f t h r e e c a t e g o r i e s s h o u l d d i f f e r . 77 T a b l e 9 p r e s e n t s t h e number o f M, R, and R-M r e s p o n s e s f o r each s e n t e n c e t y p e f o r Group 2-3 . [Group 4-5 e r r o r r a t e t*as t o o low (5%) t o b e i n f o r m a t i v e i n t h i s a n a l y s i s . ] The low p r o p o r t i o n o f R-M e r r o r s i n d i c a t e s t h a t Ss were n o t r e s p o n d i n g r andomly on e r r o r c h o i c e s b u t o n t h e b a s i s o f t h e c o n t e n t o f t h e ma in o r r e l a t i v e c l a u s e . A l t h o u g h e r r o r s were e q u a l l y o f t e n made o n t h e b a s i s o f ma in c l a u s e c o n t e n t as r e l a t i v e c l a u s e c o n t e n t , t h e r e was c o n s i d e r a b l e v a r i a b i l i t y a c r o s s s c o r e s o n d i f -f e r e n t t y p e s o f s e n t e n c e s . Compare f o r example 0 Q s c o r e s and 0^ s c o r e s , o r S „ and S s c o r e s , b o t h o f w h i c h v a r y w i t h P ronoun U s e . T h e r e was no 8 O r e a s o n t o e x p e c t t h a t P ronoun Use wou ld have s u c h a g r e a t i n f l u e n c e on whe the r t h e £ remembered t h e r e l a t i v e c l a u s e o r ma in c l a u s e c o n t e n t . I n an a t t emp t t o d e t e r m i n e t h e s o u r c e o f t h e v a r i a b i l i t y , t he s c o r e s were compared (by i n s p e c t i o n ) w i t h r e s p e c t t o t h e a c t u a l c o n t e n t f o r e a ch s e t o f s e n t e n c e s ( b o y - g i r l , d o g - c a t , b o x - b a l l ) . I t was f o u n d t h a t e r r o r s were a s s o c i a t e d w i t h b o x - b a l l and dog-ca t c o n t e n t , i n f r e q u e n t l y w i t h b e y - g i r l . When b o y - g i r l o c c u r r e d i n t h e ma in c l a u s e , more e r r o r s were a s s o c i a t e d w i t h r e l a t i v e c l a u s e c o n t e n t . When b o y - g i r l o c c u r r e d i n t h e r e l a t i v e c l a u s e , more e r r o r s were a s s o c i a t e d w i t h ma in c l a u s e c o n t e n t . T h i s f i n d i n g s u g g e s t s t h a t s e m a n t i c and r e l a t i o n a l f a c t o r s ( e . g . , t h e p e r c e p t i o n o f b o y - g i r l a s a c t o r i n a l l s e n t e n c e s ) a s w e l l as s y n t a c t i c f a c t o r s a r e Impor t an t i n a c c o u n t i n g f o r l i n g u i s t i c p e r f o r m a n c e . T u r n e r and Rommetveit (1968) have r e p o r t e d d a t a w h i c h s u p p o r t t h i s i n t e r p r e t a -t i o n . They f o u n d t h a t t h e most s a l i e n t s e m a n t i c e lement o f a p i c t u r e , whe the r t h e a c t o r o r r e c i p i e n t o f t h e a c t i o n , t ended t o become t h e s u b -j e c t o f a s e n t e n c e upon r e c a l l o f t h e p i c t u r e c o n t e n t . I m i t a t i o n I m i t a t i o n s were s c o r e d c o r r e c t whenever t h e mode l s e n t e n c e was 78 T a b l e 9 Number o f M, R and R-M Comprehens ion E r r o r s f o r Group 2-3 On R e l a t i v e S e n t e n c e s C o n d i t i o n a L o c u s o f E r r o r M a i n (M) R e l a t i v e (R) B o t h (R-M) V 8 2 2 0 V o 2 2 1 V P 3 3 0 0 s 1 2 2 0 o 6 1 1 0 P 3 5 1 S s 4 6 1 S o 7 4 0 S P 2 4 5 T o t a l 30 28 11 a C a p i t a l l e t t e r r e f e r s t o Embeddedness c o n d i t i o n ; t h e l ow e r c a s e s u b s c r i p t r e f e r s t o P ronoun Use c o n d i t i o n , n m 10 79 a c c u r a t e l y r e c a l l e d o r t h e o n l y e r r o r was one o f t h e f o l l o w i n g : (a) o m i s s i o n of a n a r t i c l e , t e n s e o r p l u r a l m a r k e r ; (b) s u b s t i t u t i o n of a r e l a t i v e p ronoun (what , who, t h a t o r w h i c h ) f o r t h e c o r r e c t o n e ; and ( c ) a p p r o p r i a t e s u b s t i t u t i o n o f p e r s o n a l p ronouns f o r noun p h r a s e s In S i m p l e s e n t e n c e s . I t s h o u l d be n o t e d t h a t t h e t o t a l c o r r e c t s c o r e o v e r e s t i m a t e s t h e c h i l d ' s ( p a r t i c u l a r l y Group 4-5 Ss ) knowledge of s t r u c t u r a l r u l e s to some e x t e n t i n t h a t s u b s t i t u t i o n s o f t h e mode l r e -l a t i v e p ronoun were a l l o w e d . T h e m a i n q u e s t i o n o f i n t e r e s t i n t h i s a n a l y s i s was s i m p l y whe the r Ss showed knowledge o f t h e r e l a t i v e c l a u s e t y p e of s t r u c t u r e , n o t whe the r t h e y h a d m a s t e r e d a l l t h e o b l i g a t o r y r u l e s . Age and S y n t a x . The mean number o f c o r r e c t l y I m i t a t e d R e l a t i v e c l a u s e and S i m p l e s e n t e n c e s i s p r e s e n t e d i n F i g . 5. A t w o - f a c t o r ana l y -s i s o f v a r i a n c e f o r Age (A) and S yn t ax (B), w i t h r e p e a t e d measures on B, was p e r f o r m e d on the mean number o f c o r r e c t i m i t a t i o n s . The r e s u l t s a r e summar ized i n T a b l e 10. Age was f o u n d t o be a h i g h l y s i g n i f i c a n t f a c t o r . Group 2-3 s c o r e d a mean o f 7.5 (21%) c o r r e c t and Group 4-5 a mean o f 24.6 (68%) c o r r e c t . Syn tax was a l s o f o u n d t o be a s i g n i f i -c a n t f a c t o r , p e r f o r m a n c e on R e l a t i v e s e n t e n c e s b e i n g p o o r e r t han o n S i m p l e . The S yn t ax e f f e c t i s c o n s i s t e n t w i t h e x p e c t a t i o n s f r o m b o t h t h e T r a n s f o r m a t i o n and Dep th h y p o t h e s e s . R e l a t i v e s e n t e n c e s r e q u i r e more t r a n s f o r m a t i o n a l o p e r a t i o n s t h a n S i m p l e and have ( i n t h e p r e s e n t s t u d y ) a g r e a t e r mean d e p t h t han S i m p l e s e n t e n c e s . Hence , R e l a t i v e s e n t e n c e s were e x p e c t e d t o be i m i t a t e d l e s s a c c u r a t e l y t han S i m p l e s e n t e n c e s b e c a u s e o f t h e g r e a t e r l o a d on memory. The Age e f f e c t i s open t o s e v e r a l i n t e r p r e t a t i o n s . P o o r p e r f o r -mance by Group 2-3 Ss on R e l a t i v e s e n t e n c e s c o u l d be I n t e r p r e t e d a s 80 1 6 r A G E G R O U P F i g . S. Mean number o f c o r r e c t r e s p o n s e s on T a s k 1 I m i t a t i o n P r o c e d u r e f o r R e l a t i v e and S i m p l e s e n t e n c e s as a f u n c t i o n o f a g e . 81 T a b l e 10 Summary o f A n a l y s i s o f V a r i a n c e o f C o r r e c t I m i t a t i o n Responses f o r Two Age G roups (A) Taken as Repea ted Measu res o n Syn tax (B) Sou r ce d f MS F P Between S u b j e c t s 19 Age (A) 1 S u b j e c t s W i t h i n G roups 18 W i t h i n S u b j e c t s 20 S yn tax (B) 1 AB 1 R e s i d u a l 18 731 .03 3 0 . 6 8 .01 2 3 . 8 3 1 6 4 . 0 3 21 .87 .01 .02 7 .50 82 (a) lack of knowledge of the Relative clause structure, (b) a consequence of the child's limited memory capacity, or (c) a product of both lack of knowledge of the structure and limited memory capacity. It was not possible to evaluate these alternatives on the basis of the number correct measure used. In order to even approach the problem of d i s t i n -guishing between lack of competence and memory overload, the number correct analysis must be viewed l n light of the types of errors Ss made. Analysis of errors i s presented in a later section under Qualitative  Data. Further interpretation of the effect of Age and Syntax on imita-tion performance i s postponed u n t i l the error data have been presented. Embeddedness and Pronoun Use. A two-factor analysis of variance for Embeddedness (B) and Pronoun Use (C), with repeated measures on B and C, was performed on the mean number of correct imitations. This was done separately for Relative and Simple data for the reasons speci-fi e d on page 61. Only Group 4-5 data were Included since only five of the ten Group 2-3 correctly imitated even one Relative clause sentence (mean of less than 1% correct). The results of the analysis of Relative data are summarized i n Table 11. Both the Embeddedness and Pronoun Use main effects were significant. A Neuman-Keuls test was used to discover the source of the Embedded-ness effect. A V > 0 > S ordering of means was found (p_< .01 for a l l comparisons). Figure 6 shows the mean number of correctly imitated Relative clause sentences plotted as a function of Embeddedness condition (order-ed from low to high mean depth), The obtained V > 0 > S ordering of means Is consistent with the ordering predicted from the average mean depth indices, and inconsistent with the V » 0 « S ordering of means expected from the Transformation hypothesis. 83 T a b l e 11 Summary o f A n a l y s i s o f V a r i a n c e o f C o r r e c t I m i t a t i o n Responses o n R e l a t i v e Sen t ences b y Group 4-5 f o r Embeddedness (B) and P ronoun Use (C) S o u r c e d f MS F P Between S u b j e c t s 9 W i t h i n S u b j e c t s 80 Embeddedness (3) 2 5.68 1 1 . 8 3 .01 P ronoun Use (C) 2 2.71 5.65 .01 BC 4 .71 1.48 NS R e s i d u a l 72 .48 E M B E D D E D N E S S F i g . 6 . Mean number o f c o r r e c t r e s p o n s e s on T a s k 1 I m i t a t i o n P r o c e d u r e f o r R e l a t i v e and S i m p l e c o n t r o l s e n t e n c e s a s a f u n c t i o n o f Embeddedness . The Neuman-Keuls was a l s o u s e d t o d e t e r m i n e t h e s o u r c e o f t h e P r o -noun Use e f f e c t . A ( s ) > ( o ) > ( p ) o r d e r i n g o f means was f o u n d l(p_< .01 f o r (p) v s (o) and ( v ) ; P <.05 f o r (o ) v s (B )J . F i g u r e 7 shows t h e mean number o f c o r r e c t l y I m i t a t e d R e l a t i v e c l a u s e s e n t e n c e s p l o t t e d a s a f u n c t i o n o f P ronoun U s e . The P ronoun Use c o n d i t i o n s , a g a i n , a r e o r -d e r e d f r om low t o h i g h a v e r a g e mean d e p t h . The f i n d i n g t h a t t h e u se o f t h e p r o n o u n a s t h e s u b j e c t o f t h e c l a u s e (s ) was e a s i e r t h a n u s e o f t h e p ronoun a s o b j e c t o f t h e r e l a t i v e c l a u s e ( o ) , o r as o b j e c t o f t h e p r e p o s i t i o n o f t h e r e l a t i v e c l a u s e ( p ) , i s c o n s i s t e n t w i t h t h e mean d e p t h s . The (o ) > (p) o r d e r i n g , howeve r , i s i n c o n s i s t e n t w i t h the (p) < (o ) o r d e r i n g o f mean d e p t h s . The o b t a i n e d (s ) > (o) > (p) o r d e r i n g i s t o t a l l y i n c o n s i s t e n t w i t h t h e l a c k o f d i f f e r e n c e s p r e d i c t e d b y t h e T r a n s f o r m a t i o n h y p o t h e s i s . The r e s u l t s o f t he t w o - f a c t o r a n a l y s i s o f v a r i a n c e on Group 4-5 S i m p l e d a t a a r e summar ized i n T a b l e 12. O n l y t he P ronoun Use e f f e c t r e a c h e d s i g n i f i c a n c e . A (p) » ( s ) > (o ) o r d e r i n g o f P ronoun Use means was f o u n d u s i n g t h e Neuman-Keuls t e s t [p_< .01 f o r (o ) v s ( s ) and ( p ) ] . The o b t a i n e d o r d e r i n g o f means i e i n c o n s i s t e n t w i t h t h e ( s ) > (p) » (o) o r d e r i n g p r e d i c t e d o n t h e b a s i s o f t h e mean dep ths (See F i g . 7). To d e t e r m i n e i f t h e o b t a i n e d V > 0 > S o r d e r i n g o f R e l a t i v e Embedded-n e s s means was a t r u e Embeddedness e f f e c t o r a f u n c t i o n o f i t e m d i f f e r -e n c e s , t h r e e s i m p l e a n a l y s e s o f v a r i a n c e f o r Syn tax (B ) , w i t h r e p e a t e d m e a s u r e s , were p e r f o r m e d . E a ch a n a l y s i s compared p e r f o r m a n c e by Group 4-5 S s o n one t ype o f Embeddedness (V , 0 o r S ) , a s i g n i f i c a n t S yn t ax d i f f e r e n c e ( S i m p l e > R e l a t i v e ) b e i n g i n t e r p r e t e d a s e v i d e n c e o f an Embeddedness e f f e c t . The r e s u l t s o f t h e t h r e e a n a l y s e s were summar ized i n T a b l e 13. The means a r e p l o t t e d i n F i g . 6. A s i g n i f i c a n t Syn tax e f f e c t was f o u n d f o r Embeddedness c o n d i t i o n s 0 and S i n d i c a t i n g t h a t t h e • RELATIVE O SIMPLE • GROUP 4-5(S0LID) • GROUP2-3(OPEN) S P P R O N O U N U S E F i g . 7. Mean number o f c o r r e c t r e s p o n s e s on T a s k 1 I m i t a t i o n P r o c e d u r e f o r R e l a t i v e and S i m p l e c o n t r o l s e n t e n c e s a s a f u n c t i o n o f P ronoun U s e . 87 T a b l e 12 Summary o f A n a l y s i s o f V a r i a n c e o f C o r r e c t I m i t a t i o n Responses o n S i m p l e S en t ences by Group 4-5 f o r Embeddedness (B) and P ronoun Use (C ) S o u r c e d f its F P Between S u b j e c t s 9 W i t h i n S u b j e c t s 80 Embeddedness (B) 2 .21 -P ronoun Use (C) 2 1.48 6 .17 .01 BC 4 .39 1 .63 NS R e s i d u a l 72 .24 88 T a b l e 13 Summary o f T h r e e A n a l y s e s o f V a r i a n c e o f C o r r e c t I m i t a t i o n Responses by Group 4-5 on Embeddedness C o n d i t i o n s V , 0 and S f o r S yn t ax (B) Embeddedness C o n d i t i o n Sou r ce d f MS Between S u b j e c t s 9. W i t h i n S u b j e c t s 10 S yn tax (B) 1 . 2 0 R e s i d u a l 9 2 .20 Between S u b j e c t s 9_ W i t h i n S u b j e c t s 10 Syn tax (B) 1 7 .20 8 .28 . 0 5 R e s i d u a l 9 . 8 7 Between S u b j e c t s 9_ W i t h i n S u b j e c t s 10 Syn tax (B) 1 33 .80 9 3 . 8 9 .01 R e s i d u a l 9 . 3 6 89 o b t a i n e d 0 > S o r d e r i n g o f R e l a t i v e means may be a t t r i b u t a b l e t o l o c u s o f embedding r a t h e r t h a n i t e m d i f f e r e n c e s . The f i n d i n g s f o r T a s k 1 I m i t a t i o n p r o c e d u r e o n t h e Embeddedness f a c t o r , b a s e d o n a n a l y s i s o f Group 4-5 p e r f o r m a n c e , may b e summar ized a s f o l l o w s : a . R e l a t i v e c l a u s e s e n t e n c e s were more d i f f i c u l t t o r e t a i l t h a n c o m p a r a b l e S i m p l e s e n t e n c e s unde r c e r t a i n c o n d i t i o n s o f end-embedding [ (0 ) e . g . , The dog s i t s on t h e box t h a t t h e g i r l h o l d s ] and u n d e r s e l f - e m b e d d i n g [ (S ) e . g . , The dog t h a t t h e g i r l h o l d s s i t s on t h e b o x . ] b . Se l f -embedded (S) r e l a t i v e c l a u s e s e n t e n c e s were more d i f f i c u l t t o r e c a l l t h a n end-embedded (V o r 0 ) . I n s p e c t i o n o f means f o r Group 2-3 ( F i g . 6) i n d i c a t e d t h a t t h e s e g e n e r a l -i z a t i o n s h o l d f o r t h e younge r g r o u p a s w e l l a s f o r Group 4 - 5 . T h e f i n d -i n g s a r e c o n s i s t e n t w i t h G a e r ' s (1969) r e p o r t t h a t c h i l d r e n ' s i m i t a t i o n p e r f o r m a n c e on s e l f - e m b e d d e d s e n t e n c e s was p o o r e r t h a n o n end-embedded and a r e a l s o c o n s i s t e n t w i t h t h e o r d e r i n g o f mean d e p t h s , s e n t e n c e s w i t h h i g h d e p t h i n d i c e s ( s e l f -embedded ) b e i n g more d i f f i c u l t t o r e c a l l t h a n s e n t e n c e s w i t h l ow mean d e p t h s . T h r e e s i m p l e a n a l y s e s o f v a r i a n c e were a l s o p e r f o r m e d on P ronoun Use d a t a t o d e t e r m i n e i f the o b t a i n e d ( s ) > (o) > (p) o r d e r i n g o f R e l a t i v e i m i t a t i o n means was a t r u e P ronoun U s e e f f e c t o r m e r e l y a f u n c t i o n o f i t e m d i f f e r e n c e s . E a ch a n a l y s i s compared Group 4-5 p e r f o r m a n c e on one P ronoun U s e c o n d i t i o n [ ( s ) , ( o ) , o r ( p ) ] , a s i g n i f i c a n t S y n t a x d i f f e r -ence ( S imp l e > R e l a t i v e ) b e i n g i n t e r p r e t e d a s e v i d e n c e o f a n Embedded-n e s s e f f e c t . T h e r e s u l t s o f t h e t h r e e a n a l y s e s a r e summar ized i n T a b l e 1 4 . (The means a r e p l o t t e d i n F i g . 7.) O n l y t h e Syn tax e f f e c t f o r P ronoun Use ( p ) , u s e o f p ronoun as o b j e c t o f t h e p r e p o s i t i o n o f t h e r e l a t i v e c l a u s e , r e a c h e d s i g n i f i c a n c e . C o u p l e d w i t h t h e l a c k o f a s i g n i f i c a n t S yn t ax e f f e c t f o r e i t h e r (s ) o r (o ) P ronoun Use c o n d i t i o n , 90 T a b l e 14 Summary o f T h r e e A n a l y s e s o f V a r i a n c e o f C o r r e c t I m i t a t i o n Responses b y G roup 4-5 on P ronoun U s e s ( s ) , (p ) and (o) f o r S yn t ax (B) P ronoun Use C o n d i t i o n Sou r ce d f MS (8) (P) Between S u b j e c t s J) W i t h i n S u b j e c t s 10 S yn t ax (B) 1 3 .20 3 .68 NS R e s i d u a l 9 . 8 7 Between S u b j e c t s 9 W i t h i n S u b j e c t s 10 S yn t ax (B) 1 3 6 . 4 5 4 0 . 9 6 .01 R e s i d u a l 9 . 8 9 (o) Between S u b j e c t s 9 W i t h i n S u b j e c t s 10 Syn tax (B) 1 1.25 R e s i d u a l 9 3.81 91 t h i s f i n d i n g i n d i c a t e s t h a t t h e o b t a i n e d ( s ) > (p) and ( o ) > (p) o r d e r i n g o f R e l a t i v e means may be a t t r i b u t a b l e to t h e (p) t r e a t m e n t r a t h e r t h a n i t e m d i f f e r e n c e s . T h e P ronoun Use f i n d i n g s b a s e d o n a n a l y s i s o f G roup A-5 d a t a o n t h e T a s k 1 I m i t a t i o n P r o c e d u r e may be summar ized a s f o l l o w s : a . R e l a t i v e c l a u s e s e n t e n c e s were more d i f f i c u l t t o r e c a l l t h a n S i m p l e unde r c e r t a i n c o n d i t i o n s o f P ronoun u s e , n a m e l y , u s e o f t h e p ronoun a s o b j e c t o f t h e p r e p o s i t i o n [ ( p ) e . g . , The g i r l h o l d s t h e box o n w h i c h t h e dog s i t s ] . b . R e l a t i v e s e n t e n c e s wh i ch employed t h e p ronoun as o b j e c t o f t h e p r e p o s i t i o n , ( p ) , were more d i f f i c u l t t o r e c a l l t h a n t h o s e w h i c h employed t h e p ronoun a s s u b j e c t ( s ) o r o b j e c t (o) o f t h e c l a u s e . T h e s e r e s u l t s a r e p u z z l i n g s i n c e P ronoun Use (p) I s s t r u c t u r a l l y no more complex t h a n P ronoun Use (o ) o r ( s ) whether v i ewed i n t e rms o f t h e t r a n s f o r m a t i o n o r c o n s t i t u e n t - s t r u c t u r e grammar m o d e l s . Y e t Ss f o u n d (p) s e n t e n c e s c o n s i d e r a b l y more d i f f i c u l t t o i m i t a t e . P i l o t d a t a c o l l e c t e d o n c o l l e g e s t u d e n t s , I n d i c a t e d t h a t i n spon taneous s p e e c h Ss t ended t o s l m p i f y t h e (p) s t r u c t u r e , e . g . , " T h e r e i s t h e box w h i c h t h e b o y s i t s o n " o c c u r r e d more f r e q u e n t l y t h a n t h e f o r m a l l y c o r r e c t v e r s i o n " T h e r e i s t h e box on. w h i c h t h e boy s i t s . " C o m p r e h e n s i o n - I m i t a t i o n T a b l e 15 p r e s e n t s t h e age and s e x o f e a ch j> and t h e number c o r r e c t on Comprehens ion and I m i t a t i o n P r o c e d u r e s . A s t r o n g c o r r e l a t i o n between Age and t o t a l C o m p r e h e n s i o n - I m i t a t i o n p e r f o r m a n c e was f o u n d , r •» . 8 6 , £ < . 0 1 . Comprehens ion s c o r e s c o r r e c t e d f o r g u e s s i n g a r e p r e s e n t e d In p a r e n t h e s e s . The c o r r e c t i o n f o r m u l a u s e d was " R i g h t minus ^ r ° n | , ' t where k e q u a l s t h e number o f r e s p o n s e a l t e r n a t i v e s (See C r o n b a c h , 1 9 6 0 ) . The Ss a r e r a n k e d i n d e c r e a s i n g o r d e r o f t h e combined Comprehens ion ( u n c o r -r e c t e d ) and I m i t a t i o n s c o r e . T a b l e 15 Number o f C o r r e c t Responses f o r e a ch S u b j e c t on T a s k 1 Comprehens ion and I m i t a t i o n P r o c e d u r e s Comprehens ion [mo.) Sex R e l a t i v e S i m p l e T o t a l 65 P 16 17 32 (32) 68 M 15 15 30 (28) 56 F 17 17 34 (33) 59 F 15 16 31 (29) 62 M 15 15 30 (28) 60 M 16 14 30 (28) 62 F 14 13 27 (24) 56 F 15 15 30 (28) 43 M 16 15 31 (29) 54 M 15 16 31 (29) 58 F 14 14 28 (25) 49 F 8 10 18 (12) 36 M 11 13 24 (20) 40 F 17 12 32 (31) 42 F 11 12 23 (19) 40 F 11 13 24 (20) 39 M 13 14 27 (24) 39 M 9 13 22 (19) 48 F 10 10 20 (15) 31 F 5 6 11 ( 3) I m i t a t i o n S i g n a R e l a t i v e S i m p l e T o t a l C - I Combined 15 17 32 es 65 14 18 32 - 62 8 18 26 + 60 11 15 26 + 57 10 16 26 + 56 10 15 25 + 55 9 16 25 - 52 11 11 22 + 52 8 12 20 + 51 9 7 16 47 6 10 16 + 44 5 16 21 39 2 12 14 + 38 1 1 2 + 34 0 9 9 + 32 1 4 5 + 29 0 1 1 + 28 0 1 1 + 23 0 1 1 + 21 0 1 1 + 12 " S i g n C-I" r e p r e s e n t s the s i g n (+ o r -) o f t h e c o r r e c t e d Comprehens ion minus I m i t a t i o n s c o r e . 93 S t a t i s t i c a l c o m p a r i s o n o f Comprehens ion and I m i t a t i o n p e r f o r m a n c e was n o t made b e c a u s e o f t h e d i f f e r e n c e s i n t h e r e s p o n s e r e q u i r e m e n t s ( p o i n t i n g v s r e p r o d u c t i o n ) . The o r d e r i n g o f t h e s c o r e s , Comprehens ion > I m i t a t i o n , f o r 80% o f t h e Ss does s u p p o r t t h e h y p o t h e s i s t h a t Comprehen -s i o n exceeds and may p r e c e d e p r o d u c t i o n . The more i n t e r e s t i n g o f t he two h y p o t h e s e s , t h a t comprehens i on p r e c e d e s p r o d u c t i o n , i s s u p p o r t e d by t h e f i n d i n g t h a t Ss who p r o d u c e d no c o r r e c t i m i t a t i o n s o f t h e R e l a t i v e c l a u s e s t r u c t u r e s b u t a t l e a s t one S i m p l e , comprehended a s many a s 72% o f t h e R e l a t i v e c l a u s e s e n t e n c e s . Summary o f T a s k 1^  R e s u l t s T h e r e s u l t s o f T a s k 1 Comprehens ion and I m i t a t i o n P r o c e d u r e s f o r e a ch v a r i a b l e m a n i p u l a t e d a r e summar ized i n T a b l e 1 6 . S yn tax and Embed-dedness were s i g n i f i c a n t f a c t o r s o n l y o n t h e I m i t a t i o n P r o c e d u r e . P r o -noun Use was a s i g n i f i c a n t f a c t o r o n b o t h Comprehens ion and I m i t a t i o n P r o c e d u r e s . 94 T a b l e 16 Summary o f R e s u l t s on T a s k 1 Comprehens ion and I m i t a t i o n P r o c e d u r e s E x p e c t e d O r d e r i n g O b t a i n e d 3 O r d e r i n g C o n d i t i o n Dep th T r a n s f o r m a t i o n Comprehens ion Syn tax S > R S > R S «* R Embeddedness ( R e l a t i v e ) V>0> S V os 0 » s v = o = s P ronoun Use ( R e l a t i v e ) (s ) > (p) > (o) ( s ) » (p) » (o) ( s ) - (o) > (p) I m i t a t i o n Syn tax S > R S > R S > R Embeddedness ( R e l a t i v e ) V > 0 > S V « 0 » S V > 0> S P ronoun Use ( R e l a t i v e ) ( s ) > (p) > (o) ( s ) » (p) • (o) (s ) = (o) > (p) G r e a t e r t h a n symbo l ( > ) f o r O b t a i n e d O r d e r i n g i n d i c a t e s p < .05. Based on number c o r r e c t measu re . 9 5 TASK 2 T a s k 2 d i f f e r e d f r om T a s k 1 i n t h e f o l l o w i n g ways : (a) t h e r e were t h r e e S yn tax v a r i a t i o n s , R e l a t i v e , A d j e c t i v e and S i m p l e , r a t h e r t han two a s i n T a s k 1; (b) P ronoun Use was n o t m a n i p u l a t e d i n T a s k 2 ; ( c ) Type o f a d j e c t i v e , b a s e o r d e r i v e d , was m a n i p u l a t e d ; and (d) c o n t e n t o f t h e s e n t e n c e s d i f f e r e d . I t was n e c e s s a r y t o d e v e l o p two s e t s o f m a t e r i a l s , T a s k 1 and 2, b e c a u s e P ronoun Use v a r i a t i o n s and t h e A d j e c t i v e S yn tax c o n d i t i o n Were n o t c o m p a t i b l e . The R e l a t i v e c l a u s e s e n t e n c e comparab l e t o a n A d j e c t i v e s e n t e n c e s u c h a s " T h e happy g i r l h o l d s t h e b e a r " i s " T h e g i r l who i s happy h o l d s t h e b e a r . " I n t h i s c a s e and i n a l l R e l a -t i v e s e n t e n c e s i n T a s k 2 , t h e r e l a t i v e p r o n o u n n e c e s s a r i l y was t h e s u b -j e c t o f t he r e l a t i v e c l a u s e . Hence , p ronoun use m a n i p u l a t i o n s c o u l d n o t b e made and s t i l l m a i n t a i n t h e s e m a n t i c c o m p a r a b i l i t y o f t h e A d j e c -t i v e and R e l a t i v e s e n t e n c e s . Method S u b j e c t s . The Ss were t h e same 20 n u r s e r y s c h o o l c h i l d r e n d e s c r i b e d f o r T a s k 1. M a t e r i a l s . T a s k 2 c o n s i s t e d o f 96 s e n t e n c e s and 96 p a i r s o f p i c -t u r e s i l l u s t r a t i n g t h e s e n t e n c e s . The s e n t e n c e s r e p r e s e n t e d 16 s e n t e n c e t y p e s w h i c h v a r i e d a c c o r d i n g t o t h r e e c r i t e r i a : S y n t a x , Type o f a d j e c -t i v e , and Embeddedness . The t h r e e Syn tax c o n d i t i o n s were R e l a t i v e c l a u s e , A d j e c t i v e and S i m p l e . The R e l a t i v e c l a u s e s e n t e n c e s were composed o f a ma in c l a u s e and one dependent c l a u s e . The A d j e c t i v e s e n t e n c e s were c o m -posed o f a s i n g l e c l a u s e , NP^ + V + NP^; e i t h e r NP^ o r NPg w a s composed ° * de t + ad j + N. S i m p l e s e n t e n c e s were p a i r s o f s e n t e n c e s , t he ma in c l a u s e and dependent c l a u s e o f t h e R e l a t i v e c l a u s e s e n t e n c e s , w r i t t e n a s two i n d e p e n d e n t s e n t e n c e s . 96 The two Types o f a d j e c t i v e c o n d i t i o n s were Base and D e r i v e d , Base a d j e c t i v e s a r e t he g roup o f a d j e c t i v e s t h a t c o n t a i n no d e r i v a t i o n a l s u f -f i x e s , s u c h as h a p p y , s h o r t and o l d . D e r i v e d a d j e c t i v e s c o n t a i n d e r i v a -t i o n a l s u f f i x e s i n d i c a t i v e o f t h e i r c o n s t r u c t i o n f r om o t h e r p a r t s o f s p e e c h . Examples a r e c r y i n g and b a r k i n g . O n l y v e r b - d e r i v e d a d j e c t i v e s were u s e d i n t he p r e s e n t e x p e r i m e n t a l t h o u g h d e r i v e d - a d j e c t i v e s may b e c o n s t r u c t e d f r om nouns a l s o . Type o f a d j e c t i v e was m a n i p u l a t e d i n t h e p r e s e n t s t u d y t o d e t e r m i n e i f T ype wou ld d i f f e r e n t i a l l y i n f l u e n c e Compre -h e n s i o n o r I m i t a t i o n p e r f o r m a n c e , even though no d i f f e r e n c e wou ld be p r e -d i c t e d on t h e b a s i s o f number o f t r a n s f o r m a t i o n s o r mean d e p t h . T h e r e were some p rob l ems w i t h c l a s s i f i c a t i o n o f S i m p l e and R e l a t i v e c l a u s e s e n t e n c e s as Ba se o r D e r i v e d . Bo th S i m p l e and R e l a t i v e c l a u s e s e n t e n c e s c o n t a i n e d b a s e a d j e c t i v e s ( e . g . , " T h e boy h o l d s t h e a p p l e s . The boy i s happy " a n d " T h e boy who i s happy h o l d s t h e a p p l e s " ) . N e i t h e r S i m p l e n o r R e l a t i v e c l a u s e s e n t e n c e s a c t u a l l y c o n t a i n e d a d e r i v e d a d j e c t i v e , however , b u t o n l y a p o t e n t i a l d e r i v e d - a d j e c t i v e ( e . g . , " T h e boy h o l d s t h e a p p l e s . The boy i s c r y i n g " and " T h e boy who i s c r y i n g h o l d s t h e a p p l e s " ) . S i n c e the Base c l a s s i f i c a t i o n a p p l i e d t o t h e S i m p l e and R e l a t i v e c l a u s e s e n t e n c e s , s e n t e n c e s n o t a c t u a l l y c o n t a i n i n g a d e -r i v e d - a d j e c t i v e , o n l y t h e p o t e n t i a l , were c l a s s i f i e d unde r D e r i v e d t o e x p e d i a t e a n a l y s i s o f t h e d a t a . I f t h i s a l l o w a n c e had n o t been made, i t wou ld have been i m p o s s i b l e t o t e s t f o r a T y p e X Syn tax i n t e r a c t i o n . I n -t e r p r e t a t i o n o f a T y p e ma in e f f e c t d i d , o f c o u r s e , r e q u i r e q u a l i f i c a t i o n s i n c e s c o r e s on s e n t e n c e s c o n t a i n i n g Base a d j e c t i v e s , D e r i v e d a d j e c t i v e s , and o n l y p o t e n t i a l d e r i v e d - a d j e c t i v e s were c o l l a p s e d f o r t h e Type e f f e c t . Such a n a l l o w a n c e was n o t made i n t h e c a s e o f t h e Embeddedness f a c -t o r f o r t h e S i m p l e s e n t e n c e s . No s i m p l e s t r u c t u r e s e n t e n c e c a n b e c o n -s t r u e d t o v a r y on t h e Embeddedness f a c t o r . A c c o r d i n g l y , t h e d e s i g n o f 97 T a s k 2 was a n i n c o m p l e t e 3 X 2 X 4 f a c t o r i a l . L o c u s o f t h e m o d i f i e d noun i n t h e s e n t e n c e , Embeddedness , v a r i e d o n l y f o r R e l a t i v e c l a u s e and A d j e c t i v e s e n t e n c e s . The f o u r l e v e l s o f Embeddedness were end-embedding b y m o d i f i c a t i o n o f t h e s u b s t a n t i v e o f t h e v e r b a l ( V ) , end-embedding b y m o d i f i c a t i o n o f t h e o b j e c t o f t h e p r e p o s i t i o n (P), end-embedding by m o d -i f i c a t i o n o f t h e o b j e c t o f t h e ma in c l a u s e ( 0 ) , and s e l f - e m b e d d i n g by m o d i f i c a t i o n o f t h e s u b j e c t o f t h e ma in c l a u s e ( S ) . I t s h o u l d be n o t e d t h a t t h e u s e o f t h e te rm Embeddedness t o c o v e r t h e v a r i a t i o n s i n l o c u s o f t h e s i n g l e - w o r d a d j e c t i v e m o d i f i e r i s n o t c o n v e n t i o n a l b u t i s c o n s i s -t e n t w i t h t h e d e r i v a t i o n a l h i s t o r y o f t h e a d j e c t i v e a c c o r d i n g t o t h e t r a n s f o r m a t i o n a l grammar and a l s o a l l o w s f o r p a r a l l e l t e r m i n o l o g y w i t h T a s k 1. An example o f each s e n t e n c e t y p e i s p r e s e n t e d i n T a b l e 1 7 . Twe l ve examples o f each o f t h e f o u r Embeddedness c o n d i t i o n s f o r Base and t w e l v e f o r D e r i v e d A d j e c t i v e s e n t e n c e s were g e n e r a t e d . The examples w i t h i n e a ch c o n d i t i o n were c o n s t r u c t e d by e s t a b l i s h i n g two s e n t e n c e f r ames f o r e a c h v a r i a t i o n o f t h e A d j e c t i v e s t r u c t u r e ( e . g . , T h e r e i s a b a s k e t ; T h e r e i s a b o y . ) E ach f r ame was u s e d f o r s i x d i f f e r e n t a d j e c t i v e s . The t w e l v e Base a d j e c t i v e s i n s e r t e d i n t h e f r ames were b i g - l i t t l e , r e d - b l u e , r o u n d - s q u a r e , s a d -h a p p y , s h o r t - t a l l , t h i n - f a t . The t w e l v e D e r i v e d a d j e c t i v e s were s i t t i n g -s t a n d i n g , c l i m b i n g - f a l l i n g , c r y i n g - l a u g h i n g , s l e e p i n g - p l a y i n g , r u n n i n g -w a l k i n g , f i s h i n g - s w i m m i n g . The a d j e c t i v e s were s e l e c t e d so as t o f o rm c o n t r a s t i n g p a i r s s i n c e t h e Comprehens ion p r o c e d u r e r e q u i r e d t h a t i t be p o s s i b l e t o c l e a r l y p i c t u r e t h e a d j e c t i v e mean ing . Many a d j e c t i v e s a r e d e f i n e d p i c t o r i a l l y i n a r e l a t i v e f a s h i o n o n l y ( e . g . , b i g - l i t t l e . ) I t was , t h e r e f o r e , n e c e s s a r y t o p r o v i d e c o n t r a s t i n g p i c t u r e s as r e s p o n s e a l t e r n a t i v e s t o make the I n t ended r e f e r e n c e c l e a r . The s e n t e n c e s i n t h e R e l a t i v e c l a u s e t r a n s f o r m a t i o n and S i m p l e T a b l e 17 Sample T a s k 2 S e n t e n c e s f o r Comprehens ion and I m i t a t i o n P r o c e d u r e s M o d i f i c a t i o n o f s u b s t a n t i v e o f v e r b a l (V) Base Adjective; S i m p l e : Relative: T h e r e i s a happy b o y . T h e r e i s a b o y . The boy i s h a p p y . T h e r e i s a boy who i s h a p p y . Derived Adjective: Simple: R e l a t i v e : T h e r e i s a c r y i n g g i r l . T h e r e i s a g i r l . The g i r l i s c r y i n g . T h e r e i s a g i r l who i s c r y i n g . M o d i f i c a t i o n o f s u b j e c t o f ma in c l a u s e (S) Base A d j e c t i v e : The happy boy h o l d s t h e a p p l e s . S i m p l e : The boy h o l d s t h e a p p l e s . The boy i s h a p p y . R e l a t i v e : The boy who i s happy h o l d s t h e a p p l e s . D e r i v e d A d j e c t i v e : The c r y i n g g i r l h o l d s t h e b e a r . S i m p l e : The g i r l h o l d s t h e b e a r . The g i r l i s c r y i n g . R e l a t i v e : The g i r l who i s c r y i n g h o l d s t h e b e a r . Modification of object of main clause (0) Base A d j e c t i v e : The dog s e e s the happy b o y . S i m p l e : The dog s e e s t h e b o y . The boy i s h a p p y . R e l a t i v e : The dog s e e s t h e boy who i s happy . D e r i v e d A d j e c t i v e : The dog s e e s the c r y i n g g i r l . S i m p l e : The dog s e e s t h e g i r l . The g i r l i s c r y i n g . R e l a t i v e : The dog s e e s t h e g i r l who i s c r y i n g . Table 17 (continued) 99 Modification of object of preposition of main clause (P) Base Adjective: The dog looks at the happy boy. Simple: The dog looks at the boy. The boy i s happy* Relative: The dog looks at the boy who i s happy. Derived Adjective: The dog looks at the crying g i r l . Simple: The dog looks at the g i r l . The g i r l i s crying. Relative: The dog looks at the g i r l who i s crying. 100 c o n d i t i o n s were w r i t t e n f r om t h e A d j e c t i v e s e n t e n c e s by mak ing t h e a p p r o -p r i a t e m o d i f i c a t i o n s . F o r examp le , " T h e t a l l boy h o l d s t h e a p p l e s " b e -came " T h e boy who i s t a l l h o l d s t h e a p p l e s " and " T h e boy h o l d s t h e a p p l e s . The boy i s t a l l . " A p o o l o f 288 s e n t e n c e s was g e n e r a t e d a c c o r d i n g t o t he method d e s -c r i b e d . A 96 i t e m t a s k was c o n s t r u c t e d f r om the s e n t e n c e p o o l i n t h e f o l l o w i n g manner : Member a o f one p a i r i n e a c h o f t h e f o u r Embeddedness c o n d i t i o n s was w r i t t e n as a r e l a t i v e c l a u s e t r a n s f o r m and member b as a s i m p l e s e n t e n c e . Member a o f a second p a i r was w r i t t e n as a r e l a t i v e c l a u s e t r a n s f o r m and member b a s a s i m p l e s e n t e n c e . Member a o f a t h i r d p a i r was w r i t t e n as an a d j e c t i v e s e n t e n c e and member b as a s i m p l e s e n -t e n c e . T h i s s y s t e m a t i c a s s i gnmen t o f c o n t e n t s t o e a ch c o n d i t i o n was c o n -t i n u e d f o r a l l s i x p a i r s o f examples i n each Embeddedness c o n d i t i o n . The r e s u l t i n g T a s k 2 c o n s i s t e d o f 96 i t e m s w i t h f o u r examples o f each o f 24 c o n d i t i o n s . Two forms o f t h e t a s k (A and B) were c o n s t r u c t e d . They d i f f e r e d o n l y i n t h e o r d e r o f t h e i t ems and the a d j e c t i v e - p a i r member I n e a ch s e n t e n c e . I tems were p r e s e n t e d i n random o r d e r . Form B o r d e r was t h e r e v e r s e o f Form A o r d e r . Yngve numbers were d e t e r m i n e d f o r each word i n e a ch s e n t e n c e and t h e mean d e p t h c a l c u l a t e d . To o b t a i n a d e p t h i n d e x f o r e a c h l e v e l o f Embeddedness t h e mean d e p t h s f o r s e n t e n c e s r e p r e s e n t i n g e a ch S yn t ax c o n -d i t i o n were a v e r a g e d , g i v i n g t h e a v e r a g e mean d e p t h . L i k e w i s e , t o o b -t a i n an i n d e x f o r each Syn tax c o n d i t i o n t h e mean d e p t h s f o r s e n t e n c e s r e p r e s e n t i n g e a ch l e v e l o f Embeddedness were a v e r a g e d . The mean d e p t h s and a v e r a g e mean dep ths a r e p r e s e n t e d i n T a b l e 1 8 . C o r r e s p o n d i n g t o each o f t h e 96 T a s k 2 s e n t e n c e s were a p a i r o f p i c t u r e s . Each p i c t u r e i n a p a i r r e p r e s e n t e d one o f t h e two c o n t r a s t i n g a d j e c t i v e s l i s t e d a b o v e , mak ing a t o t a l o f 24 d i f f e r e n t p i c t u r e s . Each 101 T a b l e 18 Ave rage Mean Dep th f o r S e n t e n c e s R e p r e s e n t i n g e a c h S yn t ax and Embeddedness C o n d i t i o n on T a s k 1 S yn tax A v e r a g e mean dep th—Embeddedness Embeddedness A d j e c t i v e S i m p l e R e l a t i v e V .80 1.00 1.00 .93 P 1 .00 1.11 1.11 1.07 0 1 .00 l . U 1 .13 1.08 S 1.17 1.11 1.38 1.22 A v e r a g e mean d e p t h — S y n t a x . 9 9 1.08 1.15 102 o f t h e t w e l v e p a i r s o f p i c t u r e s o c c u r r e d e i g h t t i m e s . P i c t u r e s were b l a c k l i n e d r aw ings o n 8 1/2 X 11 I nch w h i t e p a p e r . A l l p i c t u r e s i l l u s -t r a t i n g s e n t e n c e s w i t h b a s e a d j e c t i v e s i n c l u d e d a dog l o o k i n g a t a boy h o l d i n g a n a p p l e i n each hand o r a dog l o o k i n g a t a b a s k e t f u l l o f a p p l e s . The d e t a i l s o f p i c t u r e s i l l u s t r a t i n g each p a i r o f s e n t e n c e s d i f f e r e d o n l y i n t h e a t t r i b u e s o f t he boy o r b a s k e t d e f i n e d by t he base a d j e c t i v e s . P i c t u r e s i l l u s t r a t i n g s e n t e n c e s w i t h v e r b - d e r i v e d a d j e c t i v e s i n c l u d e d a dog l o o k i n g a t a boy h o l d i n g a t eddy b e a r , o r a dog l o o k i n g a t a g i r l h o l d i n g a t eddy b e a r . The d e t a i l o f t h e p i c t u r e s i l l u s t r a t i n g v e r b -d e r i v e d a d j e c t i v e s was n e c e s s a r i l y g r e a t e r t han t h a t i n p i c t u r e s i l l u s -t r a t i n g b a s e a d j e c t i v e s . (See A p p e n d i x B.) The p i c t u r e s were mounted i n a l o o s e - l e a f n o t e b o o k . The two p i c -t u r e s compos ing a p a i r were mounted s i d e by s i d e . T h e r e was no c o n s i s -t e n t r e l a t i o n s h i p between t h e c o r r e c t r e s p o n s e and p o s i t i o n o f t h e p i c -t u r e ( l e f t , r i g h t ) . Comprehens ion P r o c e d u r e . The d e t a i l s o f t h e Comprehens ion P r o c e -d u r e f o r T a s k 2 were i d e n t i c a l w i t h t h o s e d e s c r i b e d f o r T a s k 1, e x c e p t t h a t o n l y one n o t e b o o k was used f o r p r e s e n t a t i o n o f t h e p i c t u r e s s i n c e t h e r e were o n l y two r e s p o n s e a l t e r n a t i v e s . I m i t a t i o n P r o c e d u r e . The d e t a i l s o f t h e I m i t a t i o n P r o c e d u r e f o r T a s k 2 were i d e n t i c a l w i t h t h o s e d e s c r i b e d f o r T a s k 1. 103 Results and Discussion Comprehension Age, Type and Syntax. The mean number of correctly comprehended Relative clause, Adjective and Simple sentences for each age group i s plotted i n Fig. 8 according to Type of adjective (Base or Derived). A three-factor analysis of variance for Age (A), Type of adjective (B) and Syntax (C), with repeated measures on B and C, was performed. The results are summarized i n Table 19. Age was found to be a significant factor, with Group 2-3 scoring a mean of 78.2 (81.5%) correct and Group 4-5 scoring a mean of 94.2 (98%) correct, both well above chance level (50%). The Type main effect and the Age X Type Interaction also reached significance. A l l other factors were nonsignificant. Inspection of Type means for each age group (See Fig. 8) revealed that Type was a significant variable for Group 2-3 only, with perfor-mance on Base sentences being poorer than on Derived sentences. If the effect had been in the opposite direction, interpretation would have been d i f f i c u l t since the Derived condition did not apply equally for a l l Syntax conditions. A l l Syntax conditions did, however, contain Base adjectives. Group 2-3 performance was better on Derived Items than on Base items for a l l Syntax variations. Thus, the fact that performance on Base items was poorer than on Derived could not be interpreted as due to the absence of adjectives in some sentences, namely, Relative and Simple Derived items. The most l i k e l y interpretation of the poor performance on Base Items i s vocabulary inadequacy. Inspection of individual J5's scores on each sentence, revealed that many young Group 2-3 Ss responded randomly to items containing Base adjectives such as round, square, red, green. F i g . 8. Mean number o f c o r r e c t r e s p o n s e s on T a s k 2 Comprehens ion P r o c e d u r e f o r Base A d j e c t i v e , R e l a t i v e and S imp le s e n t e n c e s ( l e f t ) and f o r D e r i v e d A d j e c t i v e and c o n t r o l s e n t e n c e s ( r i g h t ) as a f u n c t i o n o f a g e . 105 T a b l e 19 Summary o f A n a l y s i s o f V a r i a n c e o f C o r r e c t Comprehens ion Responses f o r Two Age Groups (A) Taken as Repea ted Measu res o n Type (B) and S yn t ax (C) S o u r c e d f MS P P Between S u b j e c t s 19 Age (A) 1 213 .34 1 8 . 8 3 .01 S u b j e c t s W i t h i n Groups 18 1 1 . 3 3 W i t h i n S u b j e c t s 100 Type (B) 1 3 6 . 3 0 25 .74 .01 Syn tax (C) 2 .16 AB 1 2 0 . 8 3 1 4 . 7 7 .01 AC 2 . 50 BC 2 . 23 ABC 2 .21 R e s i d u a l 90 1.66 106 thin, and fat, in a l l syntactic contexts, but correctly to items contain-ing other Base adjectives such as big, l i t t l e , tnd happy. No such item differences were found for sentences containing )erived adjcetives. The poor performance only on senterces containing particular Base adjectives suggests that the Ss were simpXy unable to make tfc* semantic discrimin-ations necessary to answer correctly. The overall poorer performance by Group 2-3 Ss, but absence of a Syntax main effect or Age X Syntax interaction on Task 2 was consistent with the results of t i e Task 1 Comprehension Procedure. The same possi-b i l i t i e s of interpretation also remain, that either (a> a l l the Ss pos-sessed at least rudimentary knowledge of the relative clause and adjec-tive structures, the age differences simply reflecting memory differences, or (b) Ss were able to respond correctly, irrespective of the structure, on the basis of noun content, younger Ss performing poorer simply be-cause they could not re c a l l the two or three noun contents or lacked knowledge of the word meaning. Neither po s s i b i l i t y can be ruled put on the basis of Comprehension data alone. Embeddedness. A three-factor analysis of variance for Type (B), Syntax (C), and Embeddedness (D), with repeated measures on a l l factors, was performed on Relative clause and Adjective data for Group 2-3. Re-sponses to Simple sentences were analyzed separately for the reasons specified on page 61. Only Group 2-3 data were included since Group 4-5 error rate was so low (2% errors) that Its inclusion would have resulted in spurlosly low variance. The results of the analysis of Relative and Adjective data are summarized In Table 20. Only the Type and Embedded-ness factors reached significance, performance on items containing Base adjectives (e.g., happy, t a l l ) being poorer than on items containing Derived adjectives or adjective clauses (e.g., crying g i r l , g i r l who i s X07 T a b l e 20 Summary o f A n a l y s i s o f V a r i a n c e o f C o r r e c t C o m p r e h e n s i o n R e s p o n s e s b y G r o u p 2-3 f o r Type ( B ) , S y n t a x (C) a n d Embeddedness (D) S o u r c e d f MS F P B e t w e e n S u b j e c t s £ W i t h i n S u b j e c t s 150 Type ( B ) 1 8 .55 1 6 . 1 3 .01 S y n t a x ( C ) 1 . 05 Embeddedness (C) 3 1.52 2 .87 . 0 5 A B 1 . 0 7 AC 3 . 4 9 BC 3 .82 1.55 NS ABC 3 .35 -R e s i d u a l 135 . 5 3 108 crying). This latter effect has already been discussed (page 106). To discover the source of the Embeddedness effect, a Neuman-Keuls Test was used. A V » 0 « P > S ordering of means was found (]>< .01 for S vs P, 0 and V). See Fig. 9 for the mean number of correctly compre-hended Relative sentences plotted as a function of Embeddedness. The obtained ordering of means did not distinguish between the three end-embedding conditions (V, P and 0) as would have been expected from the depth indices. However, the ordering does distinguish between end-em-bedding and self-embedding as expected on the basis of depth, performance on self-embedded sentences being poorer than on end-embedded. This l a t -ter difference between Embeddedness conditions was not expected on the basis of the Transformation Hypothesis since Embeddedness conditions do not d i f f e r In the number of transformations required in derivation. A l -though the obtained ordering of means was in part consistent with the Depth prediction, interpretation was dependent on the outcome of analy-sis of Simple data. The obtained ordering of means may simply represent an Item effect, i n which case the same ordering or means would be ob-tained for Simple sentences. To check for this possibility, a two-factor analysis of variance for Type (B) and Embeddedness (C), with repeated measures on both factors, was performed on Simple data for Group 2-3. The results are summarized In Table 21. Only the Type effect was found to be significant. The failure to find a significant Embeddedness effect for Simple sentences, however, s t i l l cannot be taken as support for the conclusion that the obtained V • 0 « P > S ordering of Relative and Adjective means was due to the Embeddedness treatment effect and not item effects. To arrive at a meaningful interpretation of the obtained Embeddedness effect, i t becomes necessary to compare performance on Relative and Adjective 109 8 • RELATIVE A ADJECTIVE O SIMPLE • GROUP 4-5 (SOLID) O GROUP 2-3 (OPEN) S E M B E D D E D N E S S F i g . 9 . Mean number o f c o r r e c t r e s p o n s e s on T a s k 2 Comprehens ion P r o c e d u r e f o r A d j e c t i v e , R e l a t i v e and S i m p l e c o n t r o l s e n t e n c e s as a f u n c t i o n o f Embeddedness . 110 T a b l e 21 Summary o f A n a l y s i s o f V a r i a n c e o f C o r r e c t Comprehens ion Responses on S i m p l e S en t ences by Group 2-3 f o r Type (B) and Embeddedness (C) Sou r ce d f MS F P Between S u b j e c t s 9 W i t h i n S u b j e c t s 70 Type (B) 1 5.52 9 .20 .01 Embeddedness (C) 3 1.11 1.85 NS BC 3 . 14 -R e s i d u a l 63 . 60 I l l s e n t e n c e s t o t h a t on S i m p l e s e n t e n c e s s e p a r a t e l y f o r e a c h Embeddedness t r e a t m e n t * I n s p e c t i o n o f means r e v e a l e d , howeve r , t h a t Embeddedness h a d l i t t l e i n f l u e n c e on p e r f o r m a n c e and t h u s f u r t h e r a n a l y s i s wou ld be u n i n f o r m a t i v e . T h i s d e c i s i o n was made i n v i e w o f t h e f a c t t h a t p e r f o r -mance o n R e l a t i v e and A d j e c t i v e i t e m s was g e n e r a l l y b e t t e r t h a n o r e q u i v -a l e n t t o p e r f o r m a n c e o n S i m p l e i t e m s . I n o r d e r t o i n t e r p r e t t h e o b t a i n e d o r d e r i n g o f R e l a t i v e and A d j e c t i v e means a s due t o Embeddedness , p e r f o r -mance on t h e s e S yn tax c o n d i t i o n s had t o be s i g n i f i c a n t l y p o o r e r t h a n on S i m p l e f o r Embeddedness S. The absence o f a t r u e Embeddedness e f f e c t c o n f i r m s t h e no d i f f e r -ence p r e d i c t i o n made f r om t h e number o f T r a n s f o r m a t i o n s i n d e x b u t i s I n -c o n s i s t e n t w i t h t h e o r d e r p r e d i c t e d f r o m t h e d e p t h i n d i c e s . The same r e s u l t s were o b t a i n e d on T a s k 1 f o r Comprehens ion and b y Gae r ( 1969 ) . Comprehens ion L a t e n c y D a t a . The r a t i o n a l e f o r t h e e x p e c t e d r e -l a t i o n s h i p between s y n t a c t i c s t r u c t u r e and l a t e n c y p r e s e n t e d f o r T a s k 1 a l s o h o l d s f o r T a s k 2 (See page 7 1 ) . I n s h o r t , t h e g r e a t e r number o f t r a n s f o r m a t i o n a l o p e r a t i o n s o r t h e g r e a t e r t h e mean d e p t h , t h e l o n g e r w i l l be t h e l a t e n c y . The mean l a t e n c y o f r e s p o n s e f o r e a ch Syn tax c o n d i t i o n f o r t h e two age g r o u p s i s p r e s e n t e d i n F i g . 10 . Because o f t h e l a c k o f s t a b i l i t y o f t h e s c o r e s , l a t e n c i e s were c o l l a p s e d o v e r t h e Embeddedness f a c t o r , t h e r e s u l t b e i n g t h a t each j3 ' s l a t e n c y s c o r e was an a v e r a g e o f 32 s c o r e s . (Data f o r t he two Ss w i t h u n u s u a l l y l o n g and v a r i a b l e l a t e n c i e s were a g a i n o m i t t e d . ) A t w o - f a c t o r a n a l y s i s o f v a r i a n c e f o r Age (A) and S y n -t a x (B ) , w i t h r e p e a t e d measures on B, was p e r f o r m e d . The r e s u l t s a r e summar ized I n T a b l e 2 2 . The Age ma in e f f e c t and Age X Syn tax i n t e r -a c t i o n r e a c h e d s i g n i f i c a n c e . I n s p e c t i o n o f means (See F i g , 10) r e v e a l -ed t h a t S yn tax had l i t t l e I n f l u e n c e on Group 4-5 l a t e n c i e s b u t d i d a f f e c t 112 3 r o & 2 >-O z UJ -J < LU • RELATIVE A ADJECTIVE O SIMPLE 2 - 3 A G E G R O U P 4 - 5 F i g . 10. Mean l a t e n c y o f r e s p o n s e on T a s k 2 Compre -h e n s i o n P r o c e d u r e f o r A d j e c t i v e , R e l a t i v e and S i m p l e s e n t e n c e s as a f u n c t i o n o f a g e . 113 T a b l e 22 Summary o f A n a l y s i s o f V a r i a n c e o f L a t e n c y o f Comprehens ion Responses f o r Two Age Groups (A) Taken as Repea ted Measures on Syn tax (B) S o u r c e d f MS Between S u b j e c t s Age (A) S u b j e c t s W i t h i n Groups 17 1 16 6 .34 1.07 6 .38 .05 W i t h i n S u b j e c t s S yn t ax (B) AB R e s i d u a l 36 2 2 32 .029 .044 .012 2 .417 3.667 NS .05 114 Group 2-3 l a t e n c i e s . Group 2-3 r e q u i r e d more t ime t o r e s p o n d t o R e l a t i v e s e n t e n c e s t h a n t o A d j e c t i v e o r S i m p l e s e n t e n c e s . R e l a t i v e s e n t e n c e s were a l s o f o u n d t o r e q u i r e more t ime t han S i m p l e o n T a s k 1, b u t f o r b o t h age g r o u p s . The r e s u l t s do d i f f e r e n t i a t e between t h e two H y p o t h e s e s . The o b t a i n e d o r d e r i n g o f mean l a t e n c i e s , A d j e c t i v e • S i m p l e > R e l a t i v e , i s c l e a r l y i n c o n s i s t e n t w i t h t h e o r d e r i n g e x p e c t e d f r om t h e T r a n s f o r m a -t i o n H y p o t h e s i s : S i m p l e > R e l a t i v e > A d j e c t i v e . I t I s , i n p a r t , c o n s i s -t e n t w i t h t h e o r d e r i n g e x p e c t e d f r o m t h e mean d e p t h s : A d j e c t i v e > S i m p l e > R e l a t i v e . I m i t a t i o n The c r i t e r i a u s e d i n s c o r i n g T a s k 1 I m i t a t i o n d a t a were a l s o a p p l i e d t o T a s k 2 d a t a (See pages 77-78 ) . A g e , T y p e and S y n t a x . The mean number o f c o r r e c t l y i m i t a t e d R e l a -t i v e , A d j e c t i v e and S i m p l e s e n t e n c e s f o r e a ch age g roup i s p l o t t e d i n F i g . 11 a c c o r d i n g t o Type o f a d j e c t i v e . A t h r e e - f a c t o r a n a l y s i s o f v a r -i a n c e f o r Age (A ) , Type (B ) , and S yn tax ( C ) , w i t h r e p e a t e d measures on B and C , was c a r r i e d o u t and i s summar ized i n T a b l e 2 3 . The Syn tax ma in e f f e c t , and t h e Age X Syn tax and Type X Syn tax i n t e r a c t i o n s r e a c h e d s i g n i f i c a n c e . I n s p e c t i o n o f means f o r the Type X Syn tax i n t e r a c t i o n ( F i g . 12) r e v e a l e d t h a t Type had l i t t l e i n f l u e n c e o n i m i t a t i o n o f A d j e c t i v e o r S i m p l e s e n t e n c e s , b u t d i d a f f e c t p e r f o r m a n c e on R e l a t i v e s e n t e n c e s . Few-e r c o r r e c t i m i t a t i o n s were made on R e l a t i v e Base i t e m s ( e . g . , The dog s e e s t he g i r l who i s happy) t h a n on R e l a t i v e D e r i v e d i t e m s ( e . g . , T h e dog s e e s t h e g i r l who i s s m i l i n g ) . S i n c e R e l a t i v e s e n t e n c e s do n o t a c t u -a l l y c o n t a i n a D e r i v e d a d j e c t i v e , t h i s i n t e r a c t i o n c a n n o t be i n t e r p r e t e d as e v i d e n c e o f a Type e f f e c t . I t i s p o s s i b l e , however , t h a t t h e i n t e r -a c t i o n r e f l e c t s an a d d i t i v e e f f e c t o f s t r u c t u r a l c o m p l e x i t y and unknown A G E G R O U P A G E G R O U P Fig. 11. Mean number of correct responses on Task 2 Imitation Procedure for Base Adjective, Relative and Simple sentences (left) and for Derived Adjective and control sentences (right) as a function of age. 116 T a b l e 23 Summary o f A n a l y s i s o f V a r i a n c e o f C o r r e c t I m i t a t i o n Responses f o r Two Age Groups (A) Taken as Repeated Measu res on Type (B) and Syn tax (C) Sou r ce d f MS F P Between S u b j e c t s 19 Age (A) 1 974 .70 1 4 . 3 3 .01 Subj e c t s W i t h i n Groups 18 68 .04 W i t h i n S u b j e c t s 100 Type (B) 1 7 .50 1.74 NS S y n t a x (C) 2 1 8 5 . 4 8 4 3 . 0 3 .01 AB 1 4 . 8 0 1.11 NS AC 2 7 0 . 0 8 1 6 . 2 6 .01 BC 2 1 6 . 0 8 3.73 . 05 ABC 2 5.28 1.22 NS R e s i d u a l 90 4 .31 117 16r 14 --A 12 10 8 • RELATIVE A ADJECTIVE O SIMPLE BASE DERIVED T Y P E O F A D J E C T I V E F i g . 1 2 . T y p e X S yn t ax I n t e r a c t i o n . v o c a b u l a r y . E v i d e n c e was f o u n d i n t h e comprehens i on r e s u l t s f o r a Base a d j e c t i v e v o c a b u l a r y d e f i c i t , a t l e a s t f o r Group 2-3 Ss. A c h i l d may be a b l e t o c o r r e c t l y i m i t a t e a s e n t e n c e w i t h unknown v o c a b u l a r y o n l y i f t h e s e n t e n c e i s n o t t o o complex s t r u c t u r a l l y . A l t h o u g h an A d j e c t i v e > S i m p l e > R e l a t i v e o r d e r i n g o f S yn t ax means was f o u n d b y t he Neuman-Keuls T e s t (p_ < . 01 f o r a l l c o m p a r i s o n s ) , t h e s i g n i f i c a n t Age X S y n t a x i n t e r a c t i o n s u g g e s t s t h a t t h i s o r d e r i n g d i d n o t h o l d f o r b o t h Age g r o u p s . I n s p e c t i o n s o f t h e means (See F i g . 13) r e -v e a l e d t h a t a l t h o u g h t h e means were o r d e r e d A d j e c t i v e > S i m p l e > R e l a t i v e f o r b o t h Age g r o u p s , t h e magn i tude o f the d i f f e r e n c e between Syn tax c o n -d i t i o n s v a r i e d f o r t h e two g r o u p s . P e r f o rmance on R e l a t i v e and S i m p l e s e n t e n c e s f o r Group 2-3 Ss was m a r k e d l y p o o r e r t han o n A d j e c t i v e s e n t e n c e s b u t o n l y s l i g h t l y p o o r e r f o r Group 4-5 . The i n t e r a c t i o n i s p r o b a b l y b e s t i n t e r p r e t e d i n terms o f t h e g r e a t e r memory r e q u i r e m e n t s o f t h e S i m p l e and R e l a t i v e s e n t e n c e s due t o t h e i r g r e a t e r l e n g t h . The l o n g e r R e l a t i v e (7-9 words ) and S i m p l e (8-10 words ) s e n t e n c e s may have a p p r o a c h -ed o r exceeded t h e memory c a p a c i t y o f many Group 2-3 S s . A d j e c t i v e s e n -t e n c e s , w h i c h r anged f r o m 5-7 words i n l e n g t h , may have been w i t h i n t h e c h i l d ' s c a p a c i t y . L a c k o f knowledge o f t h e R e l a t i v e c l a u s e s t r u c t u r e may a l s o have c o n t r i b u t e d t o t he R e l a t i v e p o o r e r t h a n S i m p l e o r d e r i n g o f means. I t was n o t p o s s i b l e t o d e t e r m i n e t h e r e l a t i v e c o n t r i b u t i o n o f l e n g t h and s y n t a x . The o b t a i n e d o r d e r i n g o f S yn t ax means i s o f c o n s i d e r a b l e t h e o r e t i -c a l i m p o r t a n c e s i n c e t h e h i g h l e v e l o f p e r f o r m a n c e on A d j e c t i v e s e n t e n c e s c l e a r l y c o n t r a d i c t s e x p e c t a t i o n s b a s e d on t h e T r a n s f o r m a t i o n H y p o t h e s i s . A d j e c t i v e s e n t e n c e s were e x p e c t e d t o be most d i f f i c u l t t o r e c a l l s i n c e more t r a n s f o r m a t i o n a l o p e r a t i o n s a r e r e q u i r e d t han f o r R e l a t i v e o r S i m p l e s e n t e n c e s . In a d d i t i o n , t h e A d j e c t i v e s t r u c t u r e i s f o r m a l l y d e r i v e d F i g . 1 3 . Age X Syn tax i n t e r a c t i o n . 120 from the Relative clause T-terminal string. Hence i t would be expected that performance on Relative clause sentences would be superior during the acquisition period i f the knowledge acquired of the nominal adjec-tive can be represented by transformation rules. The ordering i s , on the other hand, entirely consistent with the depth indices based on a phrase-structure analysis of grammar. This correspondence i s of partic-ular Interest i n light of the controversy among linguists as to the best formal representation of the adjective—phrase-structure or transforma-tional. The present study suggests that the adjective i s a psychologic-a l l y easier structure than the adjectival relative clause. Since length (in words) was confounded with Syntax, this interpretation of the Syntax effect must be considered, at best, tentative. Analysis of imitation errors in a later section, Qualitative Data, and the analysis of the Em-beddedness treatment provided a firmer basis for inferences about the child's competence. Embeddedness. The mean number of correctly imitated Relative, Adjective and Simple sentences plotted as a function of Embeddedness i s presented tn Fig. 14. A three-factor analysis of variance for Type (B), Syntax (C) and Embeddedness (D), with repeated measures on a l l factors, was performed on Relative and Adjective data. Simple data were analyzed separately for the reasons specified on page 61. Only Group 2-3 data was subjected to the analysis since Group 4-5 had a very lot; error rate (7%). The results of the analysis of Relative and Adjective data are presented in Table 24. The Syntax and Embeddedness main effects were found to be s i g n i f i -cant as were the Syntax X Embeddedness and Type X Syntax X Embeddedness interactions. Inspection of Relative and Adjective means for Group 2-3 revealed that performance on Relative sentences for Embeddedness condition to pi CO TO t - »3 to OJ H» r t oa r t to • H - a Q O-9 S CA (0 M E A N N U M B E R C O R R E C T 6 co cr m co » ro r t 0» A O 3 3 H i ft O to CO O • i H h* (t) (0 f> M» f t r t w i i ft § co TJ Q. O S3 M i at O A *J CO ft s < (tt ft » O. TT > ro ex. Uu M ft 9 O r*> f t r t •* (a < r t ft H« •1 o o 2 rt 9 ft r t cu >i C O i t H " ft CO 3 r t ft 08 O it 3 o ft ft CO ~& I-l U t . H * ft TO O s r r t r t H« s^ - < ft m CD m o o m o z m co CO m CD m o a m a z m co CO CO «-ro < -"TJ -O -CO U T 2 T 122 T a b l e 24 Summary o f A n a l y s i s o f V a r i a n c e o f C o r r e c t I m i t a t i o n Responses b y Group 2-3 f o r Type <B>, S yn tax (C) and Embeddedness (D) Sou r ce d f MS F P Between S u b j e c t s W i t h i n S u b j e c t s 150 Type (B) 1 2 .25 3.04 NS S yn tax (C) 1 104 .00 140 .54 .01 Embeddedness (D) 3 3.27 4 .42 .01 BC 1 1.07 1.45 NS BD 3 1.19 1.61 MS CD 3 2 .88 3.89 .01 BCD 3 5.51 7 .45 .01 R e s i d u a l 135 .74 123 S, particularly for Derived items, was poorer than on other Embedded-ness conditions and also was poorer than performance on Adjective items in the same Embeddedness condition (See Fig. 14). The Embeddedness effect for Relative items was not unexpected, since Relative self-embed-ded (S) items had higher mean depth than end-embedded items (V, P or 0). Embeddedness had relatively l i t t l e influence on imitation of Adjective sentences, although there was a slight difference in the trends for Base and Derived Adjective items, probably contributing to the three-way interaction. To determine i f the obtained Embeddedness effect for Relative items was a true effect or due to item differences, a two-factor analysis of variance for Type (B) and Embeddedness (C), with repeated measures on both factors was performed on Simple data. The results are summarized in Table 25. Embeddedness was found to be a significant factor. A Neuman-Keuls Test was used to determine the source of the Embeddedness (item) effect. A P « 0 B S > V ordering of means was obtained (£ < .01 for V vs S, 0 and P). See Fig. 14 for the means. The relatively poorer performance on V items than on other Embeddedness conditions should be noted. The V sentences were expected to be easiest to imitate since they contained one less noun than 0, P or S sentences and had the lowest mean depth. Compare, for example, the V pair of simple sentences, "There i s the g i r l . The g i r l i s happy" to the 0 pair "The g i r l sees the dog. The g i r l i s Happy." To c l a r i f y this unexpected tendency, the Imitation error data was studied (to be reported in detail under Qualitative Data). It was found that the lox* total correct score on Simple V items was associated with a tendency for Ss to omit the f i r s t sentence when imitating pairs of Simple sentences, perhaps because the f i r s t sentence i n each pair was 124 T a b l e 25 Summary o f A n a l y s i s o f V a r i a n c e o f C o r r e c t I m i t a t i o n Responses on S i m p l e Sen tences by Group 2-3 f o r Type (B) and Embeddedness (C) Sou r ce d f MS F P Between S u b j e c t s 9 W i t h i n S u b j e c t s 70 T y p e (B) 1 2 .82 3.71 NS Embeddedness (C) 3 4 .01 5.28 .01 BC 3 .04 -R e s i d u a l 63 . 76 125 r e d u n d a n t . T h a t i s , t h e f i r s t s e n t e n c e c o n t a i n e d l i t t l e o r no i n f o r m a -t i o n beyond t h a t i n the s e c o n d s e n t e n c e . A l t h o u g h a d i f f e r e n t o r d e r i n g o f Embeddedness means was o b t a i n e d f o r S i m p l e and R e l a t i v e s e n t e n c e s , i t c o u l d n o t be c o n c l u d e d t h a t t he o b t a i n e d V •» 0 • P > S o r d e r i n g o f R e l a t i v e means was due t o t h e Embedded-n e s s t r e a t m e n t e f f e c t and n o t i t e m e f f e c t s . I t was n e c e s s a r y t h a t p e r -fo rmance on R e l a t i v e and S i m p l e s e n t e n c e s be a n a l y z e d s e p a r a t e l y f o r e a ch Embeddedness c o n d i t i o n . A c c o r d i n g l y , f o u r two-way a n a l y s e s o f v a r i a n c e f o r Type (B) and S yn tax ( C ) , w i t h r e p e a t e d measures on b o t h f a c t o r s , were c a r r i e d o u t . Each a n a l y s i s compared Group 2-3 p e r f o r m a n c e f o r one t y p e o f Embeddedness on R e l a t i v e , A d j e c t i v e and S i m p l e s e n t e n c e s . The r e s u l t s o f t h e f o u r a n a l y s e s a r e summar ized i n T a b l e 2 6 . A s i g n i f i c a n t S yn t ax ma in e f f e c t was f ound i n a l l c a s e s . A Neuman-Keuls T e s t was u s e d t o d e t e r m i n e t h e s o u r c e o f t he S yn tax e f f e c t f o r each Embeddedness c o n d i t i o n . The f o l l o w i n g o r d e r i n g s o f means were o b t a i n e d (j>< .01 f o r a l l c o m p a r i s o n s ) . Embeddedness O r d e r i n g C o n d i t i o n  V A d j e c t i v e > R e l a t i v e > S i m p l e P A d j e c t i v e > S i m p l e > R e l a t i v e S A d j e c t i v e > S i m p l e > R e l a t i v e The o r d e r i n g f o r Embeddedness c o n d i t i o n 0 had t o be c o n s i d e r e d s e p a r a t e l y s i n c e a s i g n i f i c a n t Type ma in e f f e c t and Type X S yn tax i n t e r a c t i o n were f o u n d . I n s p e c t i o n o f means r e v e a l e d t h e f o l l o w i n g o r d e r i n g <£ i n d e t e r -m i n a t e ) . (See F i g . 1 4 . ) 126 T a b l e 26 Summary o f Pou r A n a l y s e s o f V a r i a n c e o f C o r r e c t I m i t a t i o n Responses by Group 2-3 on Embeddedness C o n d i t i o n s V , P, 0 and S f o r Type (B) and Syn tax (C) Embeddedness „ . , _ -C o n d i t i o n S o u r c e d f M S Between S u b j e c t s 9 W i t h i n S u b j e c t s 50 Type (B) 1 . 0 6 -Syn t ax (C) 2 21 .52 1 8 . 3 9 .01 BC 2 1.22 1.04 NS R e s i d u a l 45 1.17 Between S u b j e c t s 9 W i t h i n S u b j e c t s 50 Type (B) 1 .01 -Syn tax (C) 2 11 .67 18 .52 .01 BC 2 1.07 1.70 NS R e s i d u a l 45 .63 T a b l e 26 ( c o n t i n u e d ) 127 Between S u b j e c t s 9 W i t h i n S u b j e c t s 50 Type (B) 1 10 .46 19 .74 .01 S yn tax (C) 2 9.01 1 7 . 0 0 .01 BC 2 2 .72 5 .13 .05 R e s i d u a l 45 . 5 3 Between S u b j e c t s 9 W i t h i n S u b j e c t s 50 Type (B) 1 .15 -s y n t a x (C) 2 2 8 . 8 0 32 .36 BC 2 . 6 0 -R e s i d u a l 45 . 8 9 X28 Embeddedness C o n d i t i o n Type O r d e r i n g 0 Base A d j e c t i v e > S i m p l e > R e l a t i v e D e r i v e d A d j e c t i v e > R e l a t i v e > S i m p l e The r e s u l t s o f t h e s e a n a l y s e s a l l o w e d f o r t h e c o n c l u s i o n t h a t t h e o b t a i n e d 0 « v o p > s o r d e r i n g o f R e l a t i v e Embeddedness ( D e r i v e d ) means i s a t t r i -b u t a b l e t o t h e Embeddedness t r e a t m e n t r a t h e r t h a n i t e m e f f e c t s . I n k e e p i n g w i t h T a s k 1 r e s u l t s , a s e n t e n c e c o n t a i n i n g a s e l f - embedded r e l a -t i v e c l a u s e was more d i f f i c u l t t o i m i t a t e t h a n a s e n t e n c e w i t h an end-embedded r e l a t i v e c l a u s e and more d i f f i c u l t t han a comparab l e p a i r o f S i m p l e s e n t e n c e s . The g r e a t e r d i f f i c u l t y o f R e l a t i v e s e l f -embedded s e n t e n c e s i s c o n s i s t e n t w i t h t h e d e p t h I n d i c e s , w h i c h were h i g h e s t f o r S i t e m s . A c c o r d i n g t o t h e Dep th H y p o t h e s i s , pos tponement o f e x p a n s i o n o f more t h a n one symbo l i s r e q u i r e d i n s e l f - embedded s e n t e n c e s , p l a c i n g a g r e a t e r demand on t h e u s e r ' s l i m i t e d memory c a p a c i t y t han S i m p l e s e n -t e n c e s , hence the p r e d i c t e d p o o r e r p e r f o r m a n c e . Se l f -embedded s e n t e n c e s do n o t d i f f e r f r om end-embedded i n t h e number o f t r a n s f o r m a t i o n s , t h u s , no d i f f e r e n c e i n d i f f i c u l t y was p r e d i c t e d f rom t h e T r a n s f o r m a t i o n H y p o t h e -s i s . C o m p r e h e n s i o n - I m i t a t i o n T a b l e 27 p r e s e n t s t h e age and s e x o f e a ch S and t h e number o f Com-p r e h e n s i o n and I m i t a t i o n P r o c e d u r e s . A s t r o n g c o r r e l a t i o n between Age and t o t a l C o m p r e h e n s i o n - I m i t a t i o n p e r f o r m a n c e was f ound as i n T a s k 1, £ » .71, £ <.01. Comprehens ion ( c o r r e c t e d f o r g u e s s i n g ) s c o r e s were b e t t e r t h a n I m i t a t i o n s c o r e s f o r 75% o f t h e Ss a s compared t o 80% o n T a s k 1, p r o v i d -i n g a d d i t i o n a l s u p p o r t f o r the n o t i o n t h a t comprehens ion p r e c e d e s 129 p r o d u c t i o n as c l e a r l y as t h e y d i d i n T a s k 1, s i n c e t h e r e were f ewe r c a s e s o f z e r o c o r r e c t i m i t a t i o n s . A l t h o u g h o v e r a l l c o r r e c t e d Comprehens ion s c o r e s were b e t t e r t h a n I m i t a t i o n s c o r e s f o r 75% o f t h e S s , Group 2-3 Ss were a c t u a l l y i m i t a t -i n g b e t t e r on A d j e c t i v e s e n t e n c e s t h a n t h e y were c o m p r e h e n d i n g . T h i s f i n d i n g s u g g e s t s t h a t i f a jJ has knowledge o f a s t r u c t u r e and t h e s e n t e n c e i s w i t h i n t h e c h i l d ' s p r o d u c t i o n c a p a c i t y , he w i l l be a b l e to c o r r e c t l y p r o d u c e , by i m i t a t i o n , s e n t e n c e s he c anno t comprehend. The p o o r com-p r e h e n s i o n s c o r e f o r most Group 2-3 Ss c a n p r o b a b l y be a t t r i b u t e d to v o c a b u l a r y d e f i c i e n c i e s r a t h e r t h a n l a c k o f knowledge o f t h e a d j e c t i v e s t r u c t u r e . Summary o f T a s k 2^  R e s u l t s The r e s u l t s o n T a s k 2 Comprehens ion and I m i t a t i o n P r o c e d u r e s f o r e a ch v a r i a b l e m a n i p u l a t e d a r e summar ized i n T a b l e 2 8 . Syn tax and Em-beddedness were s i g n i f i c a n t f a c t o r s o n l y f o r t h e I m i t a t i o n P r o c e d u r e . T a b l e 27 Number o f C o r r e c t Responses f o r each S u b j e c t on Task 2 Comprehens ion and I m i t a t i o n P r o c e d u r e s Comprehens ion I m i t a t i o n S i g n a Com-Age (mo.) Sex R e l a t i v e A d j e c t i v e S i m p l e T o t a l R e l a t i v e A d j e c t i v e S i m p l e T o t a l C - I b i n e d 60 M 32 32 32 96 (96) 32 31 32 95 191 56 F 31 31 31 93 (90) 32 31 32 95 - 188 65 F 32 32 32 96 (96) 27 32 32 91 f 187 62 F 32 32 32 96 (96) 29 32 30 91 187 59 F 32 32 32 96 (96) 29 32 39 90 f 186 68 M 29 31 29 89 (82) 32 31 32 95 - 184 56 F 32 31 31 94 (92) 24 32 32 88 f 182 62 M 32 32 32 96 (96) 22 31 30 83 + 179 54" M 30 29 32 91 (86) 26 32 36 84 175 58 F 32 31 32 95 (94) 21 30 38 79 174 49 F 27 29 30 86 (76) 26 32 30 88 - 174 43 M 27 29 29 85 (74) 29 32 27 88 - 173 36 M 26 29 27 82 (68) 20 31 29 80 - 162 40 F 28 29 29 86 (76) 17 27 19 63 + 149 42 F 25 30 27 82 (68) 14 32 20 66 + 148 40 F 31 32 32 95 (94) 8 32 13 53 + 148 39 M 26 25 24 75 (56) 8 31 16 55 + 130 39 M 22 18 22 62 (28) 8 19 0 27 + 89 31 F 28 24 17 69 (42) 0 12 0 12 + 81 48 F 21 19 20 60 (24) 3 13 1 17 + 77 a S i g n C - I r e p r e s e n t s the s i g n (+ o r -) o f the c o r r e c t e d Comprehens ion s c o r e minus I m i t a t i o n s c o r e . 131 T a b l e 28 Summary o f R e s u l t s on T a s k 2 Comprehens ion and I m i t a t i o n P r o c e d u r e s C o n d i t i o n E x p e c t e d O r d e r i n g Depth T r a n s f o r m a t i o n O b t a i n e d 3 O r d e r i n g Comprehens ion Type - - D e r i v e d > Base ' 3 Syn tax A > S > R S > R > A A » S • R Embeddedness R e l a t i v e V > P > 0 > S V • P m 0 » S V = p = 0 • S A d j e c t i v e V > P > 0 > S V • P - 0 = s V « p • 0 • S I m i t a t i o n Type - - D e r i v e d > B a s e C Syn tax A > S >R S > R > A A > S >R Embeddedness R e l a t i v e V >P >0 >S V * p - 0 - S V = P = 0 > S A d j e c t i v e V >P >0 >S V s» P a 0 *» S V • p * 0 - S ^ G r e a t e r t han symbo l ( > ) f o r O b t a i n e d O r d e r i n g i n d i c a t e s p < . 0 5 . D i f f e r e n c e s i g n i f i c a n t f o r Group 2-3 o n l y . c D i f f e r e n c e s i g n i f i c a n t f o r R e l a t i v e i t ems o n l y . Qualitative Data 132 One o f t h e ma jo r p u r p o s e s o f t h e s t u d y was t o t r a c e t h e o n t o g e n e s i s o f t h e R e l a t i v e c l a u s e and A d j e c t i v e In s p e e c h . The q u a n t i t a t i v e a n a l y -s i s o f t h e Comprehens ion and I m i t a t i o n d a t a o n l y i n d l s a t e d t h a t R e l a t i v e c l a u s e s e n t e n c e s were more d i f f i c u l t t o i m i t a t e t h a n S i m p l e s e n t e n c e s and A d j e c t i v e s e n t e n c e s , and t h a t p e r f o r m a n c e f o r a l l s t r u c t u r e s on b o t h p r o c e d u r e s Improved w i t h a g e . A l t h o u g h t h e s e f i n d i n g s a r e i m p o r t a n t i n d r a w i n g i n f e r e n c e s about t h e c h i l d ' s l e v e l o f l i n g u i s t i c compe tence , t o d e s c r i b e the c h i l d ' s e a r l y u t t e r a n c e s i n s t r u c t u r a l t e r m s , o t h e r s o u r c e s o f I n f o r m a t i o n a r e r e q u i r e d . On t h e b a s i s o f p r e v i o u s r e s e a r c h o n t h e o t h e r g r a m m a t i c a l s t r u c t u r e s ( e . g . , B rown, 1968), i t can be s a f e l y assumed t h a t t h e r e l a t i v e c l a u s e a n d / o r a d j e c t i v e do n o t f i r s t appea r i n s p e e c h as w e l l - f o r m e d s t r u c t u r e s c o n f o r m i n g t o t h e a d u l t grammar. R a t h e r , t he s t r u c t u r e s undergo s e v e r a l m o d i f i c a t i o n s , each r e s u l t i n g i n a c l o s e r a p p r o x i m a t i o n t o t h e a d u l t s t r u c t u r e . I t was t he d e s c r i p t i o n o f t he s t r u c t u r e o f e a r l y u t t e r a n c e s t h a t was t h e p r i n c i p l e g o a l o f t h e q u a l i -t a t i v e a n a l y s i s o f spon t aneous p r o d u c t i o n and i m i t a t i o n e r r o r s . Two s o u r c e s o f d a t a were u t i l i z e d f o r t h e i d e n t i f i c a t i o n and d e s -c r i p t i o n o f t h e c h i l d r e n ' s a p p r o x i m a t i o n s t o t h e a d u l t r e l a t i v e c l a u s e and a d j e c t i v e s t r u c t u r e s : (1) i m i t a t i o n s o f R e l a t i v e c l a u s e and A d j e c -t i v e s e n t e n c e s , and (2) spon taneous d e s c r i p t i o n s o f s e t s o f p i c t u r e s . I n b o t h c a s e s , e r r o r s were t h e most f r u i t f u l s o u r c e s o f i n f o r m a t i o n . C o r r e c t r e s p o n s e s were o f m i n i m a l v a l u e s i n c e t h e y c o u l d be i n t e r p r e t e d a s e v i d e n c e o f knowledge o f t h e s t r u c t u r e s o r c o u l d be s i m p l y memor ized s e q u e n c e s . L i k e w i s e , absence o f t h e s t r u c t u r e s i n s p e e c h , p a r t i c u l a r l y i n spon t aneous s p e e c h , c o u l d be g i v e n two i n t e r p r e t a t i o n s — e i t h e r t h e c h i l d l a c k e d knowledge o f t h e s t r u c t u r e o r t he s p e e c h sample was s i m p l y n o t r e p r e s e n t a t i v e o f t he c h i l d ' s f u l l s p e e c h r e p e r t o i r e . E r r o r s on t h e o t h e r h a n d , have been shown t o o f t e n r e p r e s e n t s y s t e m a t i c m o d i f i c a t i o n s 133 o f a d u l t s t r u c t u r e , w i t h i n and between c h i l d r e n (Brown, 1968 ; Menyuk, 1 9 6 9 ) . A c c o r d i n g l y , i t was assumed i n t h e p r e s e n t s t u d y t h a t t he g e n e r a l f o r m o f t h e e a r l y r u l e s , i n f e r r e d f r om t h e e r r o r s made by any c h i l d , wou ld be r e p r e s e n t a t i v e o f t h e r u l e s u s e d by o t h e r c h i l d r e n d u r i n g t h e same p e r i o d o f d e v e l o p m e n t . In o t h e r w o r d s , n o t o n l y wou ld i t be p o s s i -b l e t o i d e n t i f y r e g u l a r i t y i n t h e e a r l y s p e e c h o f a c h i l d and i n f e r u s e o f r u l e s , i t wou ld be p o s s i b l e t o i d e n t i f y r e g u l a r i t i e s i n t he fo rm o f t h e r u l e s and the sequence o f appea rance a c r o s s c h i l d r e n . The use o f a c r o s s - s e c t i o n a l a p p r o a c h i n t h i s s t u d y was b a s e d on t h e above a s s u m p t i o n . H y p o t h e s e s . From t h e T r a n s f o r m a t i o n a l H y p o t h e s i s i t was e x p e c t e d t h a t t h e p r o d u c t i v e u s e o f t h e n o m i n a l a d j e c t i v e wou ld be a l a t e r d e v e l -opment than p r o d u c t i v e u s e o f the a d j e c t i v a l r e l a t i v e c l a u s e s i n c e t he a d j e c t i v e i s a d e r i v a t i v e o f t h e r e l a t i v e c l a u s e , r e q u i r i n g two a d d i t i o n a l ma jo r t r a n s f o r m a t i o n s , T - d e l and T-NM. The o p p o s i t e sequence o f emer -gence wou ld be p r e d i c t e d f rom t h e Depth H y p o t h e s i s . A d j e c t i v e s e n t e n c e s h a v i n g a l e s s e r d e p t h t h a n comparab l e r e l a t i v e c l a u s e s e n t e n c e s a r e l i k e l y t o be w i t h i n t h e c a p a b i l i t i e s o f t he young c h i l d b e f o r e t he r e l a -t i v e c l a u s e . A l s o , on i m i t a t i o n m a t e r i a l s , a d j e c t i v e s e n t e n c e s were g e n -e r a l l y s h o r t e r ( i n words ) t h a n comparab le r e l a t i v e s e n t e n c e s and wou ld t h u s be e x p e c t e d t o be e a s i e r t o i m i t a t e . 134 Method Imitation The materials and details of the Imitation Procedure were presented in the method sections for Tasks 1 and 2. Under Quantitative Data only the number of responses which were totall y correct or correct, except for the substitution of the relative pronoun, were presented and dis-cussed. A l l other responses were treated as incorrect. Much information about the child's competence can be acquired from analysis of errors. Scoring. For the analysis of the incorrect imitation responses, a set of 12 c r i t e r i a for catergorization of responses was devised. The category symbols and c r i t e r i a for inclusion were as follows: Symbol Cr i t e r i a 2S Two simple sentences, correct semantically. Omission of articles and substitution of the subject of the second sentence with he, she or i t was allowed, (e.g., "The dog sees the boy. The boy i s happy" or "The dog sees the boy. He i s happy"). 2S Two simple sentences, semantically, (e.g., "The x dog sees the g i r l . The g i r l i s happy" for model "The g i r l sees the dog. The g i r l Is happy"). R Relative clause sentence, correct semantically, (e.g., "The dog sees the boy who i s happy"). R . Relative clause sentence, correct except for sub-u stitution of what, where, who, that or which for relative pronoun in model sentence, (e.g., "The dog sees the boy what i s happy" for model "The dog sees the boy who i s happy"). R Relative model sentence correctly Imitated except o m for omission of the relative pronoun and/or the preposition on (from on which). These errors resulted i n some semantically and structurally correct sentences which were consistent with the transformation deletion rule, T-del, (e.g., the model sentence "There i s the g i r l who s i t s on the box" was imitated as "There i s the g i r l s i t t i n g on the box"). Others were anomalous—incorrect 135 s e m a n t i c a l l y and s t r u c t u r a l l y , ( e . g . , " T h e r e I s t h e box t h e boy s i t " ) . R A r e l a t i v e p ronoun was u s e d i n t h e i m i t a t i o n b u t x t h e r e s u l t was e i t h e r s e m a n t i c a l l y i n c o r r e c t o r an i n c o m p l e t e s e n t e n c e , ( e . g . , t h e mode l " T h e dog s e e s t h e g i r l who s i t s on t h e b o x " was i m i -t a t e d " G i r l who s i t s on t h e b o x " ) . A A d j e c t i v e s e n t e n c e , c o r r e c t s e m a n t i c a l l y , ( e . g . , " T h e happy boy h o l d s t he a p p l e s " ) . A A d j e c t i v e was u s e d t o m o d i f y noun b u t r e s u l t x i n c o r r e c t s e m a n t i c a l l y o r an I n comp l e t e s e n t e n c e , ( e . g . , " T h e r e d b a s k e t " ) . S F i r s t s e n t e n c e o f two s i m p l e s e n t e n c e s o r ma in 1 c l a u s e o f r e l a t i v e o r a d j e c t i v e s e n t e n c e was c o r r e c t s e m a n t i c a l l y . Second s e n t e n c e o r r e l a t i v e c l a u s e was a b s e n t o r i n c o r r e c t seman -t i c a l l y , ( e . g . , t h e mode l " T h e dog s e e s t h e b o y who i s h a p p y " was i m i t a t e d " T h e dog s e e s t h e b o y " ) . S Second s e n t e n c e o f two s i m p l e s e n t e n c e s o r r e l a t i v e 2 c l a u s e o f r e l a t i v e s e n t e n c e was s e m a n t i c a l l y c o r r e c t . A p p r o p r i a t e noun o r p ronoun was s u b s t i t u t e d f o r r e -l a t i v e p r o n o u n i n R e l a t i v e s e n t e n c e s . F i r s t s e n t e n c e o r ma in c l a u s e was a b s e n t o r I n c o r r e c t s e m a n t i c a l l y , ( e . g . , t h e mode l " T h e dog s e e s t h e boy who i s h a p p y " was i m i t a t e d " T h e b o y i s h a p p y " ) . S One s i m p l e s e n t e n c e , i n c o r r e c t s e m a n t i c a l l y , ( e . g . , x t h e mode l " T h e dog s e e s t h e boy who i s h a p p y " was i m i t a t e d " T h e boy s e e s a d o g g i e " ) . X P r e p o s i t i o n a l p h r a s e o n l y ; one word r e s p o n s e ; v e r b p h r a s e o n l y ; no r e s p o n s e , ( e . g . , " t h e d o g g i e " ; " o n t h e b o x " ; and " g i r l r u n n i n g " ) . Spontaneous P r o d u c t i o n . A sample o f e a c h c h i l d ' s spon taneous r e s -p o n s e s t o p i c t u r e s was o b t a i n e d . P i c t u r e s were u s e d as s t i m u l i s o a s t o g a i n c o m p a r a b i l i t y a c r o s s Sis on t h e c o n t e n t o f p r o d u c t i o n s and t o m a x i -m i z e t he l i k e l i h o o d o f S s ' p r o d u c i n g a d j e c t i v e s o r a d j e c t i v a l r e l a t i v e c l a u s e s . Two s e t s o f p i c t u r e s were u s e d , S e t A and Se t B. The 44 S e t A p i c t u r e s were s e l e c t e d f r o m t h e p i c t u r e s u s e d f o r T a s k 1 and 2 Compre -h e n s i o n p r o c e d u r e s . S e t A was composed o f one sample p a i r , 12 p a i r s o f p i c t u r e s f r om T a s k 2 , and n i n e p a i r s f rom T a s k 1. The p i c t u r e s 136 represented each of the Task 1 and 2 sentence contents. Pictures were mounted in a loose leaf notebook with the two pictures of a pair mounted on adjacent pages. The two pictures differed only i n one attribute* The £ was told that today he and IS were going to look at a picture book and that E would l i k e £ to t e l l E a l l about the pictures. While E and S looked at the sample pairs of pictures, E suggested that they play a game. The game was explained as follows: You choose one of the two pictures to t e l l me about. I ' l l close my eyes and you t e l l me a l l about one picture. Then I ' l l open up my eyes and I ' l l guess which one you were talking about. The two pictures are almost the same so you'll have to t e l l me a lot about the picture. How's that? Let's try i t . With the two pictures of a pair being alike in a l l respects except one (e.g., s i t t i n g vs. standing, short vs. t a l l ) , It was expected that this procedure would maximize the likelihood of the child's Including some form of noun modification i n this speech sample i f the prerequisite grammatical knowledge were a part of his competence. Prior to the exper-iment, E had analyzed a number of Ss' protocols obtained by the presenta-tion of Blacky pictures with the standard instructions to t e l l a story about the picture (from Zohner, 1968). This procedure resulted i n l i t t l e or no expansion of noun phrases; the Ss described what the actor l n the picture was doing rather than describing the actor or other characters. Most of the younger children had to be questioned about the pictures to get them started talking. A few (two) were unable to play the game but offered spontaneous descriptions of the pictures as they were shown and/or responded to questions posed by E such as "What i s the dog looking at?", "Who's holding the apples?", "What kind of basket i s that?", or "What's the g i r l doing?". Questions were only posed when Ss failed to spontaneously describe the pictures or play the game. The 21 Set B pictures were composed of 12 pictures from Task 2, one 137 from each different content pair, and nine pictures from Task 1, one from each different content set of four. The pictures were mounted in a loose leaf notebook in a predetermined random order such that only one picture was vi s i b l e at a time. A blank page followed each picture. The £ was instructed as follows: "Let's play a different game now. You look at the picture for a minute, then turn the page and t e l l me a l l about i t . " The instructions were accompanied by a demonstration. Both sets of pictures and instructions were presented to each child. Although redundant Information was generally obtained, occasionally a child pro-ducing a low rate of speech during one game would produce a considerably higher rate of vocalizations on the other. The productions of E and S_ for the entire Production session, i n -cluding conversation and play period monologues, were tape recorded. Written protocols were obtained from the tapes. Production data was collected for a l l Ss before Imitation and Comprehension data. Subjects. Subjects were the same 20 nursery school children used for Task 1 and 2 Comprehension and Imitation Procedures. 138 Results and Discussion Relative Clause Imitation Errors. The percentage of imitation responses in each of the categories for the two age groups i s presented In Table 29 for Task 1 and i n Table 30 for Task 2. The underscored percentages Indicate responses semantically and structurally equivalent to the model sentences. A l l other percentages represent the proportion of the total responses repre-sentative of a particular type of error for one age group and syntax con-dition. Errors made in imitating Relative sentences on the two tasks were of four main types*. Omission (S„, S , R ); Simplification (2S, 2S ); 1 2 om x Redundancy (R ); and Substitution (R ). Examples of each type of error x sub follow ( a l l from Task 2). Omission 1. Model: The dog looks at the boy who i s s i t t i n g . Reprod: The boy i s si t t i n g . 2. Model: The basket that i s blue holds the apples. Reprod: The basket holds the apples. (Never obtained "The basket is blue.") 3. Model: There i s the dog that the l i t t l e g i r l pets. Reprod: There i s the dog the l i t t l e g i r l pets. Simplification 1. Model: The dog looks at the g i r l who i s running. Reprod: The dog looks at the g i r l . The g i r l Is running. Redundancy 1. Model: The dog sees the basket that i s round. Reprod: The dog sees the basket it—who Is round. 2. Model: The g i r l who i s laughing holds a bear. Reprod: The g i r l who i s laughing the g i r l holds a bear. T a b l e 29 P e r c e n t a g e o f I m i t a t i o n s i n each o f 10 C a t e g o r i e s on T a s k 1 f o r R e l a t i v e and S imp l e Sen t ences C a t e g o r y C o n d i t i o n Age 2S 2S X R sub R om R X S 1 S 2 S X X S imp l e 2-3 y r . 32 .8 8 .3 0 0 . 6 1 .0 1.6 34 .4 1 6 . 7 4 .4 4-5 y r . 79.4 7.8 1.0 . 6 . 6 2 .8 3.3 2 .8 1.6 0 R e l a t i v e 2-3 y r . 1.6 6 .7 3.9 5.5 1 2 . 8 6 . 7 7.2 6.1 2 8 . 3 21 .1 4-5 y r . .6 .2 33 .3 2 3 . 9 8 .9 1 9 . 4 1.0 0 2.8 9 .4 U n d e r s c o r e d p e r c e n t a g e s a r e t he p e r c e n t a g e o f i m i t a t i o n s m a t c h i n g t h e mode l s e n t e n c e , i . e . , s e m a n t i c a l l y and s t r u c t u r a l l y c o r r e c t . Table 30 Percentage of Imitations in each of 12 Categories on Task 2 for Relative and Simple Sentences Category Condition Age 2 S 2 S R R R R A A S S S X x s u b om x x 1 2 x Base Simple 2-3 yr. 53.1 .6 1.9 0 .6 1.3 1.9 .6 4.4 31.3 1.3 3.1 4-5 yr. 92.5 3.1 2.5 0 0 1.3 0 0 0 0 .6 0 Relative 2-3 yr. 4.4 1.3 25.6 10.6 7.5 5.0 4.4 1.9 5.6 15.6 11.9 6.9 4-5 yr. 8.8 .6 47.5 30.6 .6 10.0 0 0 .6 0 1.3 0 Derived Simple 2-3 yr. 43.8 3.1 4.4 0 .6 .6 .6 0 4.4 35.6 5.0 1.9 4-5 yr. 96.9 0 1.3 0 0 .6 0 0 0 .6 .6 0 Relative 2-3 yr. 5.0 .6 46.3 0 9.4 6.9 0 .6 5.6 15.0 5.6 5.0 4-5 yr. 1.3 0 73.1 20.0 0 5.0 0 0 0 0 .6 0 Underscored percentages are the percentage of imitations matching the model sentence, i.e . , semantically and structurally correct. 141 Substitution 1. Model: The basket that holds the apples is blue. Reprod: The basket what holds the apples i s blue. It was from errors such as those above that inferences about the child's competence could be made with most confidence. Errors, unlike correct imitations, could not be interpreted as parrotting. Er-rors of simplification, redundancy and substitution were particularly interesting since they indicated that the Ss committing such errors under-stood that a sentence such as "The dog sees the basket that i s round" i s semantically equivalent to "The dog sees the basket. It i s round." It was found for Task 1 that only 8.3% of the 91.6% errors on Rela-tive sentences for Group 2-3 were simplifications. This finding i s sur-prising i n light of the relatively high level of comprehension (69%) of Relative sentences. It was expected that even i f the Relative sentences exceeded Ss' imitation capabilities their errors would be quite predict-able. Specifically, i t was expected that the relative clause would be disembedded, and the sentence simplified into i t s two simple sentence components (e.g., "The dog sees the basket that i s round" would become "The dog sees the basket. The basket i s round"). An important assump-tion l i e s behind this expectation, namely, that Ss are able to imitate two Simple sentences. Only If the Ss can correctly imitate two Simple sentences, Is i t l i k e l y that they w i l l be able to perform the Simplifica-tion of Relative sentences. The high percentage (67.2%) of imitation errors on Simple sentences for Group 2-3 suggests that this basic assump-tion was not met. It might be expected that the older Ss would exhibit a high level of simplification errors on Relative sentences, since at least they could imitate pairs of Simple sentences (only 20% errors). It was found, 142 however, that simplification errors of the type discussed above were even more rare among Group 4-5 than Group 2-3 (.8%). In addition, performance on Relative sentences was greatly improved i n comparison to Group 2-3 per-formance. Only 14% of the 66.6% errors made by Group 4-5 on Imitation of Relative sentences were not close approximations to the relative clause structure. In general, the results suggest that by the time Ss were able to correctly imitate two Simple sentences, they were also able to at least approximate the Relative model sentence. This conclusion was con-firmed by Task 2 error percentages. These results are consistent with the observations reported by others (e.g., Henyuk, 1969) which indicate that syntactic development does not follow a simple course predictable from transformation grammar. Children simply do not produce well-formed simple active sentences before other structures are attempted. This state of a f f a i r s makes i t especially d i f -f i c u l t to accurately predict performance on the basis of a grammar model. Omission errors were by far the most frequently occuring error In the Group 2-3 protocols, particularly on Simple sentences. Subjects tended to correctly imitate the second of two Simple sentences, omitting the f i r s t simple sentence (See category S o, Table 29). On Task 2 these Ss also made many omission errors on Relative sentences, omitting the main clause i f the clause was end-embedded. On Task 1, however, Group 2-3 made few systematic omission errors. More than half of their errors were in the S^ and X categories, productions which were semantically and structurally incorrect and often anomolous. The large proportion of omission errors on Task 2 and the high proportion of X and S errors on Task 1 support the tentative conclusion from analysis of number correct (Quantitative Data) that the relative clause construction had l i t t l e or no realization l n most Group 2-3 SS* grammar. 143 Omission errors decreased with age and were replaced by other types which depended on some knowledge of the relative clause structure being imitated. These were substitution and redundancy errors. Substitution errors were particularly abundant and Interesting. Pronoun substitutions were made by 11 Ss Task 1 (30% of Group 2-3; 80% of Group 4-5). The Increase in substitution errors with age contrasts with Menyuk's report (1969) that this type of error decreases with age. The discrepancy in results i s easily accountable in terms of the difference i n age range of Ss in the two experiments, Ss being younger In the present study. Substi-tution errors must appear before they decrease. The present study ob-served the increase; Menyuk's study the decrease. In general, the age trend indicates that prior to observation of the obligatory rules of pro-noun selection, Ss often make substitutions. The interesting question, of course, i s what does a £ substitute and Why? Table 31 presents the substitutions made by each !> on Task 1. The pronoun occurring in the two model sentences representing each sentence type Is presented In the l e f t column. Of the four substitutes used, the most frequently occurring was what (59%), the next most frequent that (27%), and the least frequent who (11%). Where only occurred once. A l -though the predominant use of what as a substitute i n Imitations has also been reported by Menyuk (1969), the frequency analysis of substitutes made in the present study and i n Menyuk's was found to be misleading In some respects and to overlook an important aspect of the data. While what was the most frequently used substitute, not a l l of the Ss (4/11) used i t even once. A l l of the Ss did, however, tend to use one substi-tute predominately, whether what, that or who. In fact, the more substi-tutions an IS made, the more li k e l y he was to consistently use just one substitute. This tendency, not detectable by a frequency analysis, i s 144 Table 31 Relative Pronoun Substitutions for Task 1 Imitation Procedure Model Group 2-3 Group 4-5 8 10 11 8 who who what what that what that that that that that that what what what what -what what what which which what what what that that that that what that -that that what who who who what who what o that that what that - that what what what what which where what which - that that S s who who what what that what what what what that - that that that that what what what what who what what what what S P 145 interesting i n that i t indicates not only that deviant imitation reflects lack of differentiation of the relative pronoun class, but also that there are individual differences i n the pronoun predominately employed as a substitute. The pronoun what was, however, the most Interesting and probably the most "primitive" of the substitutes by virtue of the fact that i t i s not one of the relative pronouns that occurs i n an adjective clause i n adult speech. What: functions as a relative pronoun i n adult speech, but only occurs i n noun clauses (e.g., I know what i t i s ) . Although this latter use of the relative clause was not the focus of the study, the noun clause Is closely related to the adjective clause In i t s internal structure. It was reasoned that a search through spontaneous productions for instances of the use of what i n noun and adjective clauses might provide evidence regarding the source of the child's deviant use of what in the adjective clause. A discussion of the results of this search follows. Well-formed* noun clauses and adverb clauses were found to appear i n speech before any, even approximate, adjective clauses appeared. By way of example, one g i r l , 3.6 years, did not correctly imitate any Task 1 Relative sentences. Her closest approximation included the substitution of where for the model relative pronoun. Adjectival relative clause sen-tences were also absent from her spontaneous speech record. She did, however, spontaneously produce an impressive number of adverb and noun clauses such as: 1. That what we say. 2. That what we named our dog. 3. I don't know where this goes. 4. I don't know which one i t i s . 5. Wonder how i t get l i t t l e . *Well-formed means here that restrictions on the choice of relative pro-noun or relative adverb were followed. 1A6 No deviations i n word order such as "I know what i s that" were ob-served i n any of the protocols. This word order deviation was reported by Menyuk (1969) as frequent during the preschool period. She suggested that the deviations represented the S/s early use of a + Wh Question rule, where the £ simply adds two sentences together, S^ + S 2 , in the manner two sentences would be joined by conjunction. There was no e v i -dence that these Ss had acquired any knowledge of, or were able to per-form substitution and embedding operations. Assuming that Menyuk's analogy between the word order deviation on relative clause sentences and the question Is well-founded and has a bearing on the present findings, i t may be proposed that the use of what in the adjective clause i s related to the Wh interrogative pronoun which Brown (1968) has reported to be the f i r s t used interrogative pronoun in the primitive question, "What dat?". In the present study the use of what in the adjective clause may represent a regression to an undifferen-tiated use of interrogative pronouns, necessitated by the demand of pro-ducing a new structure. It is not an uncommon observation that a seem-ingly well-established restriction i s temporarily lost when a new struc-ture i s in the early acquisition period (e.g., Bellugi, 1964). Although the above discussion of noun and adjectival relative clauses suggests an accounting for the source of the child's ungrammati-cal use of the pronoun what in the present study (Task 1), i t does not offer any clues as to the reason for the lack of differentiation of the relative pronoun in the adjective clause in contrast to the differentia-tion of adverbs and pronouns observed in the same S^ 's noun and adverb clauses. It may be that differentiation of the relative pronoun in the adjectival clause procedes at a particularly slow rate because of the absence of readily identifiable cues allowing for attribute identification, 147 a precursor to rule learning. An additional factor may be that the pro-noun In the adjective clause plays a relatively insignificant role i n semantic interpretation compared with the pronoun in the noun or adverb clause. The use or an Inappropriate pronoun i n the adjectival clause can be shown to have l i t t l e effect on the message. Compare, for example, the following two hypothetical sentences, both of which substitute what for who. Adjective Clause: I see a g i r l what's (who's) pretty. Noun Clause: I don't know what (who) i t i s . The meaning of the second sentence was completely altered by the substi-tution while interpretation of the f i r s t was minimally affected because the pronoun was redundant with the noun that the clause modified* The insignificance of the relative pronoun for unambiguous Interpretation i n many adjective clauses i s formally reflected in the deletion trans-formation (T-del), by which the pronoun may be omitted as i n "I see a dog (that is) barking loudly" or "I sees the dog (that) the boy kicked." On Task 2 as on Task 1, a large proportion of errors on Relative Items were substitution errors. The substitutions made by each £ on Task 2 are presented i n Table 32. The pronoun occurring i n the model sentence Is presented i n the l e f t column. The most frequently occurring substitute was that (44%), the next most frequent what (33%), and the least frequent who (23%). Two findings were of particular interest. F i r s t , the frequency of that and who was higher than on Task 1, especially who. Second, only half of the Ss making substitutions on Task 2 Base items made substitu-tions on Derived items (6/12 Ss). The discrepancy In results between tasks and within Task 2 suggests that much caution must be exercised i n making generalizations about competence on the basis even of Imitation Table 32 Relative Pronoun Substitutions for Task 2 Imitation Procedure Group 2-3 Group 4-5 Model : 8 9 10 11 12 Base that  that  who who who what what what who who what who who that that that that what what who what what that who  that that who what who who that that what who that who what what what what who what who what who  who  that who what that that that that that that that what who what that  that  that who who who what what who who who who who what what what what who who what what what Table 32 (continued) Group 2-3 Group 4-5 Model 8 9 10 11 12 Derived V who - that - that who - that - - that that who - that - that who - that - that - that who - - - - - what - - that who - that - that who - that - that what who - what - that who - that - that who - - -• - - - - - that what who - that - that who - - - - that - that who - - - - - - - that who - that - that who - - - - that - that who - - - - that 150 errors. There are many factors controlling the frequency and type of error i n addition to syntax that have only begun to be explored. The results of Task 2 substitution errors do support the observation made on the basis of Task 1 data that Ss use one pronoun predominately i n making substitutions. Only four of the 12 Ss making substitutions contributed to the most frequently occurring pronoun, that. Again, a simple frequency analysis provided a misleading picture of substitution errors. In general, whether or not the child w i l l substitute and what he w i l l substitute i s perhaps best considered to be a function of (a) the pronouns presented i n the model sentences and (b) the level of d i f f e r -entiation of the pronoun for the S. Imitation errors were categorized l n an attempt to determine what i t i s a child does know about the structure of a sentence i f he i s not able to accurately reproduce i t . On the basis of substitution, simplification and redundancy errors, the inference seems warranted that most Group 4-5 Ss, and a few as young as three years, had at least rudimentary knowledge of the relative clause structure. Although many could not accurately produce the model, through their errors they demonstrated that they under-stood that "The dog sees the basket that i s round" i s semantically equiva-lent to "The dog sees the basket. The basket i s round" and also equiva-lent to "The dog sees the basket. It i s round." This inference i s further supported by the finding that generally jSs who made substitution and simplification errors also correctly imitated many of the Relative clause sentences and were near asymptote on comprehension, especially on Task 2. It was only by their imitation errors, however, that It was possible to determine whether their correct imitations reflected gramma-t i c a l knowledge or reproduction by rote memory and to determine i f they had acquired knowledge of relationships, that they could see the 151 underlying similarity of sentences differing In surface structure. The imitation error data (substitution errors) did Indicate that although there was evidence that four and five year old preschool children have acquired some knowledge of the relative clause structure, differentia-tion of the relative pronoun l n the adjective clause i s a relatively late development. Spontaneous Production Data. Although the Ss* systematic Imitation errors indicated that most Group 4 - 5 Ss and some Group 2-3 Ss had at least rudimentary understanding of the grammatical relations underlying the relative clause, a description of the structure of the relative clause prior to the use of substitutions was not readily abstracted from the imitation error data. That i s , the question of what form the child's noun modifications take prior to NP + V + NP + relative pronoun + VP was not answerable from the Imitation data. Omission errors which were the most prevalent i n the younger Sa' protocols gave l i t t l e Information. The spontaneous speech protocols proved a more f r u i t f u l source of hypotheses about the child's early grammar of the relative clause. The spontaneous productions may be summarized as follows. The length, structural complexity, and comprehensiveness of Ss' description of pictures Increased dramatically with age from "That boy" to "A boy s i t t i n g on a b a l l " to "That's a l i t t l e boy s i t t i n g on a b a l l with his hand touching the b a l l . " The changes in their verbalizations were par-ti c u l a r l y striking In light of the fact that a l l the productions were ln response to the same set of stimulus pictures for two and a half year olds as well as the five and a half year olds. The examples given above were by different age Ss but were a l l ln response to the same picture. Protocols were examined for any evidence of early modifications of the noun phrase which might serve as a basis for describing and 152 understanding the ontogenesis of the adjectival relative clause. "Exam-ination" Involved categorization of utterances with similar structure together; specifically, any utterance with noun modification other than the single word adjective was compared with a l l other utterances involv-ing noun modification to check for equivalences of priviledge of occur-rence. The results of these comparisons follow. The earliest modifica-tions of the noun phrase were of two types: (1) modification of the noun with a prepositional phrase, characteristically introduced by the preposition with (e.g., A boy with a kite ) ; and (2) modification of the noun with a participle phrase (e.g., A boy si t t i n g on a box). Only one Group 2-3 S, produced even one utterance which approximated the T-rel terminal form of the relative clause. This one utterance was an incom-plete sentence and Included a substitution type of error (A boy what s i t s on a box). Not a l l instances of the f i r s t type of modification, NP +• with + VP, were of interest, only those i n which the with phrase could be replaced by a relative clause without substantially altering the meaning. That i s , the preposition could be replaced by that has, who has, or who i s + V. There were many Instances where such substitutions could not be made as In "The l i t t l e g i r l was si t t i n g on a l i t t l e piece of wood with her teddy bear." However, the utterance "A boy with a kite" could be alter-nately produced as "A boy who has a kite" or "A boy who i s flying a kite" or "A boy who i s holding a kite." This use of the with phrase was found in the protocols of 13 of the Ss ranging tn age from 3.3 to 5.8 years, four Group 2-3 SB and nine Group 4-5 Ss. The use of the with phrase in preference to a relative clause where semantically possible was not pecu-l i a r to nursery school children. In a pretest of the stimulus materials with college students, the same preference for the with phrase was 153 observed in. some Ss. A common description of a picture read as follows: "That's a boy with a dog and he has two apples In his hand and..." There was only one clear instance suggesting that the with phrase has the same prlviledges of occurrence as the relative clause. One S (3.7 years) used the with phrase l n the same context as the relative pronoun. 1. There's an apple thing that has apples i n i t . 2. The thing with the apples are ln . Although the observations in the present study were suggestive, they were based on many too few instances to allow for more than a tentative hypoth-esis that the with phrase i s ontogenetlcally related to the development of the relative clause. A second type of evidence supporting the Interpretation that the with phrase and the relative clause are psychologically related for some Ss, was also i n the form of syntactic errors, specifically, redun-dancy errors. Again the evidence i s spares, In that only one J3 (5.A years) produced clear examples of redundant usage of what and with. The subject produced "The kitty's s i t t i n g on a b a l l what with the g i r l hold-ing i t " rather than the grammatical utterance "The kitty's s i t t i n g on the b a l l that the l i t t l e g i r l holds." These errors of substitution and redundancy, Interpreted as evidence of an underlying equivalence of the with phrase and the relative clause in some preschool children's grammars, would not be predictable from the transformational grammar model. The transformational model derives the relative clause by transformation of two K-terminal strings, not by re-writing the NP. The lack of theoretical basis for these observations, however, i s not the only puzzling aspect of this data. No instances of the with phrase occurred as substitution or simplification errors on the imitation procedures for either Task 1 or Task 2. 154 The second type of noun modification, which also occurred through-out the age range studied, was modification of the NP by a participle phrase (e.g., It's a boy si t t i n g on a log). For the younger Ss there was some problem i n interpretation of instances of NP + participle phrase since often the entire utterance was NP + participle phrase rather than NP + participle phrase + VP or NP + V + NP + participle phrase (e.g., "A boy s i t t i n g on a log" rather than a complete sentence "The boy sit t i n g on the log i s singing" or "That's a boy sit t i n g on a log"). The NP + participle phrase utterance could be interpreted as telegraphic speech in which the child has omitted the auxiliary (e.g., "A kit t y s i t t i n g on a b a l l " may be a telegraphic form of "A kitty i s sit t i n g on a b a l l " ) . On the other hand, the utterance could be interpreted as an instance of noun modification i n which the relative pronoun and auxiliary have been deleted (e.g., "A kitty s i t t i n g on a b a l l " may be equivalent to "A kitty who i s si t t i n g on a b a l l " which stems from "That's a kitty. The kitty i s sit t i n g on a b a l l " ) . Although even the youngest £ produced utterances with well-formed progressive verbs (e.g., The kitty cat's watching), i t was not possible to determine i f other utterances such as "The baby watching i t " repre-sented a telegraphic omission of the i s or whether the utterance repre-sented "There i s a baby who i s watching i t . " Most j>s three years or older, however, produced some unambiguous Instances of the use of the participle phrase as a noun modifier as well as the ambiguous versions: £ l a . Look at the l i t t l e boy seeing that doggie and look at that l i t t l e boy seeing the doggie. (3.3 years) b. A k i t t y s i t t i n g on a b a l l . jS 2a. That's a boy si t t i n g on these and... (3.3 years) b. Boy si t t i n g on his dog. 155 j5 3a. There's a boy holding a kite. (4.6 years) b. A dog and a boy holding a kite. The unambiguous a examples of noun modification and the ambiguous b examples were i n each case produced by the same child. Even though there was no way of determining the intent of the child on b productions, the a Instances did indicate that the participle phrase was functioning as a noun modifier i n these Ss' speech. The occurrence of production se-quences such as "A g i r l . A g i r l holding a bear. A g i r l running away" indicated that many of the b type utterances may also represent instances of noun modification. The finding of clear evidence of the early use of the NP + participle  phrase structure ie of considerable theoretical significance. According to the transformational grammar model, utterances formally represented as NP^ + V + NPg + V + in& + prep + NP3 (e.g., It's a dog looking at a bat), are derived by application of the relative clause transformation, Tyrel, joining two base strings, followed by application of the optional T-del transformation. The utterances of the form NP + participle phrase ob-served i n the present study represent the result of application of T-del following the transformational model. If the number of transformations and derivational priority of transformations as stated by the model i s a useful index of structural complexity, utterances with relative clause structure would be expected to appear before instances Involving addition-a l transformation such as T-del. The data clearly do not support this expectation. Only one of the Group 2-3 Ss produced even one relative pro-noun or approximation to an adjective clause, but a l l except the youngest S> produced unambiguous instances of participle phrases used as noun mod-i f i e r s . It could be argued that the early instances of the participle phrase 156 do not represent deletion transformations but were simply Imitations of adult utterances. Adult Ss do generally opt to omit the relative pro-noun and auxiliary when the surface realization would be who i s or that i s [e.g., The boy sees the g i r l (who is) walking up the steps]. The wide variety of semantic contexts i n which the participle phrase appeared and occasional ungrammatlcal overgeneralizatlon of the basic rule argues against the interpretation of the children's productions as memorized sequences. There was, however, no evidence that they reflect knowledge of transformation rules such as T-rel and T-del. The fact that the participle modifier appeared earlier than the re-lative clause i n spontaneous speech may simply indicate that the logical derivation of these structures i s not mirrored in actual production. Xn part, this may be because the grammar does not take into account the semantic insignificance of the relative pronoun in adjective clauses. It i s true that the relative clause Is a more versatile and general struc-ture than the NP + participle phrase structure that ideally must take i t s place i n the child's grammar as the basic form of adjectival clause mod-if i c a t i o n , a l l other forms being special cases. The development of know-ledge and use of the structures, however, clearly does not follow a se-quence predictable from the transformational grammar model. Neither of the two early appearing forms of modification of the NP discussed contained relative pronouns. It was found that the occurrence of the relative pronoun in spontaneous speech increased with age but did not replace the earlier forms, with phrase and participle phrase. Only one Group 2-3 .S produced utterances complete with relative pronoun, while a l l but two Group 4-5 Ss spontaneously produced at least one utter-ance containing an adjectival relative clause. In a l l cases the pronoun served as the subject of the relative clause (e.g., A l i t t l e boy that's 157 crying), which la consistent with the generally lower mean depth of such sentences. In addition, relative clauses were always end-embedded. No self-embedded relative clause sentences were spontaneously produced. As was observed i n imitation data, differentiation of the usage of the re l a -tive pronoun was minimal in spontaneous production. Even the oldest Ss employed a single pronoun, what or that, i n a l l contexts. The ontogenesis of the multiple-word noun modifications can be summarized as follows: 1. No noun modification but stringing together of simple sentences, e.g., "There's a boy and he's carrying a bear and...." 2. Modification of NP by (a) with + NP, or (b) participle phrase, usually not a complete sentence, e.g., "Boy with a bear" or "Boy si t t i n g on a box." 3. Modification of NP by (a) with + NP, (b) participle phrase, or (c) relative pronoun + VP, but with l i t t l e differentiation of the pronoun and usually not a complete sentence, e.g., "Basket what i s f u l l " or "Boy what i s f a l l i n g . " 4. Modification of f i n a l NP of sentence by (a) with + NP, (b) participle phrase, or (c) relative pronoun + VP, but s t i l l with l i t t l e differentiation of the relative pronoun, the main difference being that the modified NP i s a constitutent of a sentence, not simply a phrase as in 1, 2 and 3 above, e.g., "The boy i s carry-ing a basket that Is f u l l " i s produced rather than "A basket that i s f u l l " or "A boy carrying a basket." Adjective Imitation Errors. The percentage of imitation responses ln each of the 12 categories for the two age groups i s presented In Table 33. The underscored percentages indicate responses semantically and struc-turally equivalent to the model sentences. A l l other percentages repre-sent error percentages. In comparison with performance on Relative and Simple sentences (See Table 29), few errors were made on Adjective sentences by either Table 33 Percentage of Imitations in each of 12 Categories on Task 2 for Adjective Sentences Condition Age 2S 2S Category sub R otn Adjective Base Derived 2-3 yr. 4-5 yr. 2-3 yr. 4-5 yr. 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 80.6 99.3 82.5 96.9 9.4 .6 15.6 2.5 2.5 0 .6 .6 .6 0 0 0 4.4 0 .6 0 2.5 0 .6 0 Underscored percentages are the percentage of imitations matching the model sentence, I.e., semantically and structurally correct. 159 age group (fewer than 20% errors for Group 2-3; fewer than 5% errors for Group 4-5). Because of the low error rate, Imitation errors for Adjec-tive sentences were not a particularly informative source of data about the ontogenesis of the adjective structure. The errors did, however, support the basic inference arrived at from comprehension and total correct on imitation, that the adjective was a rule-governed structure for the S. The best representation of the type of rule, rewrite or trans-formational, internalized by the Ss remains to be established. Certain types of modification of the model sentences were particu-l a r l y convincing that the Ss had acquired knowledge of the equivalence of the common grammatical relations underlying Adjective and Relative sentences. For example, two of the Group 2-3 Ss transformed Relative sentences into Adjective sentences (e.g., the model, "The dog sees the basket that i s blue," was Imitated, "The dog sees the blue basket"). Such a modification can be interpreted with l i t t l e doubt as reflecting knowledge of the semantic equivalence of the two sentences. Suggesting that the modification i s evidence that the child has Internalized a set of transformational grammar rules, linking the relative clause and adjec-tive derivationally, i s probably not warranted, however. Many more In-stances would be required. Spontaneous Production Data. Spontaneous production data fa i l e d to provide any clearer picture of the emergence of the adjective than did imitation errors. Even in Group 2-3, adjectives were used in a variety of contexts suggesting that they were not introduced simply as vocabulary units. Adjectives occurred in the nominal ("the big dog") and as a sub-stantive of the verbal ("they are round"). Several interesting tenden-cies were noted in the spontaneous utterances including adjectives, the f i r s t of which indicated that despite the productive use of the adjective differentiation of classes (noun and adjective) was not complete for some 160 subjects. Two Sa (3.3 and 4.6 years) produced utterances In which adjectives were accorded the same priviledges of occurrence as nouns, e.g., a black, there's a green, and two reds again. The absence of a noun when the adjective was preceded by a_ or two and the pluralization of the adjective red i n the last example, support the interpretation that these utterances were overgenerallzations of the noun class. Occasional imitation errors made by Group 2-3 Ss also support this interpretation. The noun was sometimes omitted i n reproduction of the model sentence, e.g., the model "The blue basket holds the apples" was imitated "The blue holds the apples." A l l cases of overextention of the noun class to include adjec-tives as exemplified above Involved colors. Another interesting observation In spontaneous production protocols was a tendency to use the adjective l i t t l e i n a seemingly indiscriminate manner. Some Ss also added the adjective l i t t l e l n imitation, e.g., the model "The boy i s holding the apples" was imitated "The l i t t l e boy i s holding the apples." In spontaneous production both Group 2-3 and 4-5 Ss modified the nouns with l i t t l e when there was no physical d i f f e r -ence i n size or in age of the referents in the two pictures being des-cribed. For example, the child was shown two pictures identical except for f a c i a l expression of a g i r l and was asked to describe one such that E could guess which one he were describing. The child sometimes produced , , T h e l i t t l e g i r l i s looking at the l i t t l e doggie" rather than "The g i r l i s looking at the dog" or "The g i r l Is looking at the doggie." If l i t t l e were the only adjective used by Ss and were used consis-tently with certain nouns, i t s occurrence would be best interpreted as a learned response unit. Other adjectives were produced in contexts shared with l i t t l e and l i t t l e occurred with many different nouns, 161 Indicating that the Ss* production of l i t t l e and other adjectives was a constructive process rather than one involving rote memorization. See Table 34 for presentation of the adjectives produced by four Ss. Nouns which were modified by more than one of the adjectives l i s t e d for a sub-ject are designated by an asterisk. These examples suggest that adjec-tive production was indeed a rule-governed process. The seemingly indiscriminate use of l i t t l e i n the nominative by some Ss requires special explanation. Many Instances of the occurrence o f l i t t l e l n the nominative can perhaps best be considered a diminuative form. L i t t l e may serve two functions: (1) to specify relative size, and (2) as a diminuative form. English does not have a noun ending as in some languages that can be added to any noun to denote affection or ln reference to children. The suffix - i e i s added to some nouns as a diminuative form, e.g., doggie, but cannot be added to a l l nouns, e.g., boy. In English an adjective often must be employed to convey these special meanings, usually the adjective l i t t l e . It i s well-known that adults frequently modify nouns with l i t t l e when in the presence of children or when referring to children or children's a c t i v i t i e s , toy, clothes, etc. The use of l i t t l e as a diminuative form by preschool Sa may simply reflect the frequency with which the adults they are in association use i t . One would expect individual differences i n fr e -quency of usage of this adjective form, depending upon the S'a linguis-t i c environment. It should be pointed out that for the Ss who used l i t t l e most fre-quently, there was clear evidence that these children distinguished be-tween the use of the adjective as a diminuative and as a descriptive adjective, denoting size or age, i n the form of redundancy errors. Note the use of l i t t l e l n the following examples. X62 Table 34 Contexts of Nominal Adjectives for Four Subjects Miml (3.4 years) l i t t l e boy teddy bear doggie* basket* one* b a l l * bench* g i r l kitty blue one* red bows flowers one* bl£ dog* brother apples* basket* striped shirt bench* long legs b a l l * funny name two apples* black thing dog* Ricky (3.7 years) l i t t l e boy* new puzzle* two birthdays fat pages big boy* fi s h one puzzle* funny kite Lori (4.11 years) l i t t l e boy g i r l * basket* round box basket* b a l l happy face smile funny place big g i r l * square one basket* pointed ear two apples skinny pants Table 34 (continued) 163 Troy (5.2 years) boy Ms basket* grass legs* g i r l doggie blue basket* shoes* basket* buckled shoes* box* piece of wood thin legs* basket* fat legs* basket* red one box* •Indicates that the noun was also modified by another adjective, e.g., the noun "legs" was modified by thin and by fat. 164 1. The l i t t l e boy Is l i t t l e . (5.0 years) 2. The l i t t l e tinsy l i t t l e boy... (5.2 years) Adults would never modify a noun with the same adjective twice as these Ss have done. The double appearance of l i t t l e i n these utterances dem-onstrates that " l i t t l e boy" does not have the same meaning for the S as "boy Is l i t t l e " or "tinsy boy." Another interesting observation was that adjectives were used less frequently by most Group 2-3 Ss. As a group, however, Group 2-3 Ss pro-duced as many different adjectives as did Group 4-5. The adjectives pro-duced by both groups are presented i n Table 35. Many adjectives did not overlap for the two groups. The equal number of adjectives occurring i n the protocols of the two groups i s puzzling and perhaps mlsrepresentative of the younger Ss actual a b i l i t y to use adjectives to achieve detailed descriptions of the pictures. Even when probed by questioning designed to draw the child's attention to the distinguishing characteristic of a picture, e.g., color, height, weight, shape, etc., some Ss responded as i f they had not even preceived the attributes distinguishing one picture from another. If they did respond by single-word adjective noun modifi-cation, often the result was an inaccurate description of the feature. See Table 35 for examples of descriptions by two Group 2-3 Ss and two Group 4-5 Ss of the same pictures. It may be that despite the younger Ss' productive use of the adjec-tive and f a i r l y extensive vocabulary, often they failed to recognize the distinguishing feature of a picture or did not have both words des-cribing the ends of a continlum at their disposal. Note that In Table 36, Group 2-3 Ss produced round but not square, fat but not thin, and l i t t l e but not t a l l . Also, the color of baskets were often Inaccurately labeled even though the Ss did produce both colors, red and blue. Some 165 Table 35 Examples of Picture Descriptions by Two Group 2-3 and Two Group 4-5 Subjects Mike (3.3 years) Subject shown two pictures alike i n a l l respects except for weight of the boy. S: Hey, apples, a doggy and a boy. E: Who's this dog looking at? Si At this dog too. E: Are these boys just the same? jS: Ja. JS; Or are they different? Si Different. E: What kind of boy i s this? What does he look like? S; You know. Hey, me push one of those things. Troy (5.2 years) Subject was shown two pictures alike in a l l respects except for weight of the boy; same pictures as Mike described above. St The l i t t l e boy i s holding an apple ln each hand and one hand i s down a l i t t l e lower and one hand i s up a l i t t l e b i t and the dog i s looking at him and one foot's over this a way; one's back. E: What kind of boy Is he? S: He's closing his eyes and he's—let's see—he has thin legs and he's a Chinese boy. E: And who's holding the apples i n this picture (pointing to other boy)? Si He has fat legs and a dog's watching him and he's holding apples in each hand. Table 35 (continued) 166 Karl (3,6 years) Subject shown two pictures alike except for shape of basket. S.: The doggy wants to eat apples again and the dog wants in the basket. E: What holds the apples? S: In the basket. E: What kind of basket Is that? 55: A—the doggy sleeps In i t . E: And what about this one (pointing to other basket)? S: Other dog sleeps i n i t . Dale (4.6 years) Subject shown two pictures alike except for shape of basket; same picture as Karl described above. j>: That one's round and this one's squared. There's a l i t t l e box with some apples in i t and the dog's by i t , and there's a round-square one with some apples i n i t and the dog's by It. Table 36 Adjectives Produced In Spontaneous Speech 167 Group 2-3 Group 2-3 Group 4-5 and only only Group 4-5 l i t t l e old* square big new small blue nice t a l l e r * red long green black heavy* pink white punky skinny happy sick* pointed sad tight buckled fat curly thin funny scary walking round pretty yellow* two Icky strong striped soft* high* crying straight red-orange* red-black *Only occurred as substantive of the verbal, never in NP. 168 Ss failed to note the color distinction at a l l , maintaining the baskets were black. Failure to differentiate pictures of people or to differentiate objects on the basis of characteristics such as color, shape, size, ex-pression, etc. i s not restricted to language tasks but has been repeatedly observed on perceptual and intellectual tasks during the preschool period (cf., Bruner, 1964; Fla v e l l , 1967; Werner, 1948). If the child i s not able to make the discriminations necessary to differentiate two pictures such as those used i n the present study, there would be l i t t l e reason to expect that the child would be able to apply verbal labels accurately even i f the words are a part of his vocabulary. The i n a b i l i t y of some Group 2-3 Ss to use adjectives effectively to express differences in reality (pairs of pictures) may be related to their level of intellectual and perceptual functioning and not specifically to their lack of syntactic knowledge of the adjective. A f i n a l observation of interest was that despite the fact that per-formance was better on Derived adjective items on imitation than on Base, Derived adjectives were almost non-existent i n spontaneous speech. The low frequency of derived adjectives (e.g., laughing g i r l ) for pre-school children was also found by Menyuk (1969). 169 General Discussion Summarizing the main findings for factors common to Tasks 1 and 2, i t was found that (a) Group 2-3 performed significantly poorer than Group 4-5 on both the Imitation and Comprehension Procedures; (b) Syntax was a significant factor for Imitation but not Comprehension (number correct measure); and (c) Embeddedness on Relative items was a significant fac-tor for Imitation but on Comprehension, self-embedded sentences being more d i f f i c u l t to imitate than end-embedded. Summarizing the main findings of the imitation error analysis and of spontaneous production data, i t was found that (a) the NP + with + NP and NP + participle phrase were earlier occurring forms of multiple word noun modification than the relative clause; (b) Ss used the adjective in the nominal productively long before relative clauses were produced; (c) by five years of age Ss did, however, use the relative clause productively as a noun modifier, although (d) even the oldest Ss (5.5 - 5.8 years) showed l i t t l e differentiation of the relative pronoun in imitation (evi-dences as substitutions) or in spontaneous production. In addition, i t was found that (e) a l l spontaneously produced relative clause sentences were end-embedded, that i s , no S spontaneously produced sentences with a self-embedded relative clause. The absence of self-embedded sentences in spontaneous speech was consistent with the greater d i f f i c u l t y of re-c a l l in imitation of self-embedded sentences, especially on Task 1. The purpose of the present study was two-fold: (a) to examine two performance models, and (b) to gather data which would allow for formu-lation of specific hypotheses about the child's knowledge of the relative clause and adjective. The results pertaining to goal A w i l l be discussed f i r s t . 170 Performance Models. Performance models cannot actually be discussed entirely independently of competence models since some assumptions about the nature of what i t i s the child i s learning about the regularities of his language are unavoidably made. The form of the knowledge attributed to the child—phrase-structure rules, transformation rules, or associa-tions—undoubtedly influences to some extent the conceptualization of production and comprehension processes even though one makes a clear def-i n i t i o n a l distinction between performance and competence. Many researchers studying the acquisition of syntax have adopted the transformational grammar model as a descriptive, predictive, and explanatory model of the sequence of syntactic development and as a representation of competence despite the fact that they stress the im-portance of distinguishing between performance and competence (e.g., McNeill, 1966). Careful examination of the results of current studies suggests, however, that the ontogeny of any structure i s not predictable from the transformational grammar (e.g., Bellugl, 1964; Brown, 1968; McNeill, 1966). This means basically that a structure may be observed in productive use before instances of i t s derivationally prior structure have appeared. The results of the present study were in agreement with these previous studies. Taking the transformational grammar as a model of competence, the predicted sequence of emergence of the studied struc-tures would be Simple, Relative, Relative-deletion, and f i n a l l y Adjec-tive. It was found, however, that in spontaneous speech, the Adjective preceded the Relative clause and the Relative-deletion preceded the Re-lative clause. These orderings of spontaneous production of structures suggest that the markedly better performance on Adjective than Relative sentences on the Imitation Procedure was not simply due to the shorter length of the Adjective sentences but that knowledge of the Adjective 171 had been internalized prior to that of the Relative clause. These findings are not surprising when viewed in light of research with adults stemming from the notion that transformational complexity corresponds to psychological d i f f i c u l t y (Miller, 1962). There i s l i t t l e evidence supporting this position that performance i s a direct reflec-tion of grammatical competence, i n particular, a set of transformation rules (e.g., Clifton & Odom, 1966). This is not to say that the langu-age user's competence i s not potentially representable by a set of trans-formation rules but that the processes underlying comprehension and pro-duction are not isomorphic with the formal derivational relations (Miller & McNeill, ]969). There are Important constraints operative on the language user's production and comprehension, most notable memory constraints, which set limits on the number and kind of operations the user performs. Certainly a device with unlimited or at least very large short-term memory capacity might be expected to perform such that there would be a f a i r l y close correspondence between transformational complex-i t y and psychological complexity, also between transformational complexity and sequence of development. The human i s not such a device, but has limited memory capacity. Psychological d i f f i c u l t y of the Relative clause and Adjective were actually better predicted by the depth index in the present study than the number of transformations index of complexity. The inference that the constituent structure grammar model which is incorporated into the Yngve performance model, then must be a more accurate representation of the user's li n g u i s t i c knowledge, does not necessarily follow. This statement Is based on the meager but suggestive evidence noted above that performance i s not necessarily a true reflection of competence. The predictive power of the depth index leads to some rather interesting 172 speculations, however. Fir s t a review of Yngve's basic hypothesis i s necessary. The language user i s characterized as a f i n i t e state device which applies rules by sucessive expansion from the top of the tree down, moving from left-to-right. Because of limited temporary memory of the language user, the structure of the sentences must not place too great of demands on memory or the production w i l l have to be aborted and another attempt made. The depth index by which predictions of rela-tive d i f f i c u l t y were made in the present study i s purported to provide a numerical estimate of the proportion of memory that has b' en occupied by a given sentence. Since the memory span for an adult has been found to approximately seven units, a sentence having a mean depth greater than seven would probably not be produced or understood. Yngve places considerable importance on the sequential nature of sentence production, and as McNeill (1968) has proposed for comprehen-sion, time and memory space are c r i t i c a l factors affecting performance. With the emphasis on the rule-governed nature of production and compre-hension, those operating on the assumption that the language user's competence may be best represented by a set of transformational and phrase-structure rules, have tended to neglect the sequential nature of language processing (cf., Lashley, 1951). A speaker cannot say a whole sentence at once but produces each word and phrase in turn, from begin-ning to end. Likewise, the listn e r begins to process a sentence as soon as the f i r s t word i s heard, not after the entire sentence has been uttered. The fact that rate of speech and presence or absence of suprasegmental features can influence i n t e l l i g i b i l i t y (Scholes, 1969), however, suggests that a word-to-word sequential model of performance would be inadequate. A performance model must, nevertheless, be able to account for the user's left-to-right or beginning-to-end processing 173 of sentences. This aspect of performance has not been ex p l i c i t l y In-corporated into current models of performance based on the transforma-tional grammar (Miller & Chomsky, 1963). It i s possible that the only way to handle the rule-governed but sequential nature of language performance i s to postulate that language users are processing information in parallel (cf., Neisser, 1967). At the same time that a speaker is expanding a construction into i t s immed-iate constituents, he has a representation of the basic underlying mean-ing that he intends to convey in the completed utterance. This repre-sentation serves to maintain the direction for the utterance being constructed. The importance and necessity of this assumption of parallel processing becomes clear i f one asks the questions, what process or mechanism ensures that when a speaker terminates a sentence that he w i l l have at least approximated communication of his original intent and not wandered completely off on a tangent? In addition, how i s i t that he i s able to evaluate the adequacy with which he has expressed his Intent? It i s not uncommon to hear a speaker remark, "That's not what I meant: I really haven't said i t very well," and then begin again. To suggest that language users are processing information in parallel i s not sufficient. The nature of the processes or operations being carried out at each level must be as clearly specified as possible. On one level (Level 1) the surface structure of the sentence i s the primary data being processed. The speaker i s successively differentia-ting constructions into their immediate constituents starting from #S# as suggested by Yngve. On another level (Level 2) the speaker i s carry-ing on the thought processes giving rise to and defining the basic re-lationships between actor, action, and e f f e c t — o r the deep structure. Taking this notion further, i t i s postulated that the sequencing of 174 words w i l l follow the sequence of the idea. The speaker sees a chair which reminds him of a cat he had as a boy. It was his favorite chair u n t i l the cat ruined i t by scratching. In production, the speaker starts "That chair,..is just like the one that my cat scratched a l l up." On the other hand, had the speaker seen a cat, not a chair, the production would have been more li k e l y to proceed, "That cat looks just like one I had at home. He used to scratch a l l the furniture. He even ruined my favorite chair." For each of the examples, i t i s suggested that the basic relationships are given on Level 2, the actual production arrived at by Level 1 sequential processes. Basically, the suggestion i s that the speaker does not know where he i s going structurally u n t i l he i s on his way; he knows what basic relationships he wants to express (Level 2) but the surface structure i t s e l f evolves as successive thoughts are transformed into words. This conceptualization of the production process leads to a different explan-ation of the d i f f i c u l t y of self-embedded sentences than that given by Yngve. Speakers may get themselves into trouble because they don't remember where they have been, not only because they don't remember where they are going, as Yngve has suggested. A speaker can only be sure of verb-tense agreement when the verb i s separated from i t s subject by a relative clause only i f he remembers the plurality of the noun. The greater d i f f i c u l t y of r e c a l l or anticipation where only the right branch of a sentence i s presented supports this notion (Forster, 1967). A number of recent studies support the suggestion that the syntax of a sentence evolves to match the content; that i s , a sentence Is simply "structured content" (Prentice, 1966; Taylor, 1969, Turner & Rommetveit, 1968), structure being influenced by the perceptual salience of the actor or acted upon or the importance attached to the actor or 175 acted upon as was suggested In the example of the cat and chair. Turner and Rommetviet (1968) for example, found that the focus of one's atten-tion can Influence the structure of a sentence, active or passive. Likewise, Prentice (1966) found that active sentences were learned more easily i f the actor was the most salient element. Passive sentences were learned more easily i f the acted upon element was most salient. The problem of incorporating a set of rules into a model of per-formance without being put in the position of having to assume that the formal derivational operations reflect psychological operations s t i l l remains. In light of the above discussion, the most f r u i t f u l way to con-front the problem i s to view the transformation rule as primarly a formal representation of the language user's knowledge of such relation-ships as the common underlying meaning of sentences differing only in structure, e.g., "The g i r l i s s i t t i n g on the porch. She is my sis t e r " and "The g i r l s i t t i n g on the porch is my sister." The language user does recognize the semantic equivalence of these two sentences (e.g., Clifton, Kurcz & Jenkins, 1965) and may demonstrate that he does in the case that a listner does not attend when the speaker produces a sentence such as, "The g i r l s i t t i n g on the porch i s my sister", and asks for a repetition. This time the speaker may utter, "See that g i r l s i t t i n g on the porch. She i s my sis t e r . " Such knowledge i s not represented in models of com-petence other than the transformational. Specification of the best representation of the message above awaits a new model of performance. A model such as Yngve's which incorporates a constituent structure grammar f a i l s to account for the language user's knowledge of relationship between structures. In contrast, a model such as that proposed by Miller and Chomsky (1963) f a i l s to adequately account for the sequential nature of production. Neither model takes 176 into consideration the myriad of factors thought to Influence performance such as focus of attention (Turner & Rommetveit, 1968); abstractness of the topic (Taylor, 1969); length; truth (Slobin, 1966); syntax (Johnson, 1966, Slobin, 1966; Martin & Roberts, 1966) and the potential but as yet undefined factors. The proposal of an adequate model w i l l be dependent upon much addition empirical work and also an attempt to integrate find-ings from the memory and information processing literature. Problems in Inferring Competence. The use of two tasks in the present study lead to an interesting finding that has considerable bear-ing on the use of performance data to infer competence. Performance on Task 1 was found to be consistently poorer than on Task 2 on both Compre-hension (corrected for guessing) and Imitation Procedures. The d i f f e r -ence in performance on items comparable in length and structure was puzzling and of considerable consequence to the interpretation of the results. It was found that Ss who correctly imitated no Relative sentences on Task 1, imitated as many as 44% of the Relative sentences on Task 2. Likewise, Ss who scored as low as 3 total correct on Task 1 Comprehen-sion, scored as many as 24 on Task 2 Comprehension (both scores corrected for guessing). The difference in level of performance on the two tasks was strikingly illustrated in the imitation protocol of the youngest ^ (2.6 yrs.). On Task 1 she produced only one word or a phrase In imita-tion of Relative sentences but on Task 2 generally imitated the string underlying the Insert correctly on end-embedded sentences as in the example below. Task 1 Model: The g i r l pets the dog that s i t s on the b a l l . Reprod: The dog... the cat. 177 Task 2 Model: The dog looks at the boy who i s f a l l i n g . Reprod: The boy is f a l l i n g . On self-embedded Relative sentences, the subject frequently repeated the model omitting the relative pronoun and sometimes the auxiliary i s , as in the following examples from Task 2. Model: The boy who i s happy holds the apples. Reprod: The boy happy holds the apples. Model: The boy who i s f a l l i n g holds the bear. Reprod: The boy i s f a l l i n g holds the bear. The S/s consistent omission of the relative pronoun without further modification of the sentence suggests that the relative clause had no realization in the child's grammar. These Task 2 imitations, however, contrast sharply with the one word or phrase Imitations of sentences of the same structure on Task 1. This discrepancy of results raises the question of whether the child might be able to correctly imitate relative sentences in yet a third task. If so, how does an experimentor decide which task actually provides the truest estimate of the child's knowledge of the relative clause structure. It has generally been argued that the errors Ss make in imitating are good indicators of their level of understanding of a structure (e.g., Fraser, Bellugi & Brown, 1963; Menyuk, 1969). The differences in performance on the two tasks by the same Ss in the present study suggest, however, that the type of errors obtained from any given set of materials may lead to considerable mis-representation of the child's competence. The solution i s , perhaps, to include more than one set of sentences and to employ more than one pro-cedure in any study of the acquisition of syntax in order to avoid erron-eous inferences about competence. Even with complementary sources of information, however, the problem of deciding which task or procedure 178 has provided the most accurate estimate of the child's competence remains. There are no obvious c r i t e r i a for distinguishing between memorized se-quences, on the one hand, and poor performance due to non-syntactic factors, on the other, on imitation tasks. Neither i s i t always possible to arrive at a comprehension task which w i l l allow unambiguous inter-pretation of the data. Only through major methodological and theoretical advances i n this area of study in the next decade w i l l these problems be solved. These problems are not unique to the study of lin g u i s t i c development but plague the entire discipline of cognitive psychology. 179 Summary The goals of the study were two-fold: (1) to examine the adequacy of the transformational model as a predictor of sentence d i f f i c u l t y and ontogeny, and (2) to gather data which would allow for specific hypothe-ses about the rules representing the child's early knowledge of the adjectival relative clause and descriptive adjective. The Ss were 20 nursery school children ranging in age from 2.6 years to 5.8 years. Subjects were divided into two groups of 10 each according to age, Group 2-3 (mean age 3.6 years) and Group 4-5 (mean age 5.0 years). A l l Ss were tested Individually under three procedures (Spontaneous Production, Comprehension, and Imitation) and two tasks (Tasks 1 and 2). Spontaneous Production was operationally the utterances produced by Ss during con-versation with E and in description of a set of pictures. Comprehension was operationally the correct selection of a picture from a set of alter-natives to match a sentence read by E. Imitation was operationally the correct reproduction of a sentence read by E. A l l of each 55's and E's utterances were tape-recorded and later transcribed. Sentences presented for Task 1 Comprehension and Imitation Proce-dures consisted of 36 sentences which varied according to three c r i t e r i a : Syntax (relative or simple); Embeddedness [end- (2 levels) or sel f -embedded]; and Pronoun Use (subject, object, or object of preposition). Sentences for Task 2 Comprehension and Imitation Procedures consisted of 96 sentences which also varied according to three c r i t e r i a : Syntax (adjective, relative, or simple); Type of adjective (base or derived); and Embeddedness [end- (3 levels) or self-embedded]. Corresponding to each sentence content was a set of four pictures (Task 1) or pairs of pictures (Task 2) which served as response alternatives during the Com-prehension Procedure. Sixty of the pictures were also used as stimulus 180 m a t e r i a l s f o r Spontaneous P r o d u c t i o n . Dependent measures were number c o r r e c t ( I m i t a t i o n and C o m p r e h e n s i o n ) , l a t e n c y (Comprehens i on ) , number o f e r r o r s i n each o f t h r e e c a t e g o r i e s (Task 1, C o m p r e h e n s i o n ) , and p e r c e n t a g e o f e r r o r s i n each o f 12 e r r o r c a t e g o r i e s ( I m i t a t i o n ) . S p o n -t aneous P r o d u c t i o n d a t a were n o t s u b j e c t e d t o q u a n t i t a t i v e a n a l y s i s , r a t h e r examples were used t o c l a r i f y and supp lement I m i t a t i o n and Com-p r e h e n s i o n d a t a . P r e d i c t i o n r e g a r d i n g d i f f i c u l t y and on togeny o f s e n t e n c e t y p e s were made on the b a s i s o f a v e r a g e mean d e p t h (Yngve Dep th H y p o t h e s i s ) and number o f t r a n s f o r m a t i o n a l o p e r a t i o n s ( T r a n s f o r m a t i o n H y p o t h e s i s ) . On the b a s i s o f mean d e p t h an A d j e c t i v e > S imp l e > R e l a t i v e o r d e r i n g o f I m i t a t i o n and Comprehens ion means(number c o r r e c t ) as p r e d i c t e d , w h i l e on the b a s i s o f number o f t r a n s f o r m a t i o n s a S imp le > R e l a t i v e > A d j e c t i v e o r d e r i n g was p r e d i c t e d . The sequence o f emergence o f t h e s e s t r u c t u r e s i n spon taneous s p e e c h was e x p e c t e d t o f o l l o w the above o r d e r i n g s . D i f -f e r e n t i a l p r e d i c t i o n s were a l s o made f o r the ocus o f Embeddedness v a r i a -b l e . On t h e b a s i s o f number o f t r a n s f o r m a t i o n s no d i f f e r e n c e s i n l o c u s o f embedding were e x p e c t e d , w h i l e on t h e b a s i s o f mean d e p t h s e l f -embedded s e n t e n c e s were e x p e c t e d t o be more d i f f i c u l t and t o emerge l a t e r t han end-embedded s e n t e n c e s . On t h e b a s i s o f number o f t r a n s f o r -m a t i o n s no d i f f e r e n c e s were a l s o p r e d i c t e d f o r t h e P ronoun Use f a c t o r , w h i l e f rom mean dep ths s e n t e n c e s i n w h i c h the o b j e c t s e r v e d as t he r e l -a t i v e p ronoun were e x p e c t e d to be more d i f f i c u l t and emerge l a t e r t han t h o s e i n w h i c h the p ronoun s e r v e d as s u b j e c t o r o b j e c t o f t h e p r e p o s i -t i o n o f t he r e l a t i v e c l a u s e . The p r e d i c t i v e i n d i c e s were n o t a p p l i c a b l e t o t he Type o f a d j e c t i v e v a r i a b l e m a n i p u l a t e d i n T a s k 2 , hence a no d i f f e r e n c e h y p o t h e s i s was made. Age was f o u n d t o be a h i g h l y s i g n i f i c a n t f a c t o r i n a l l a n a l y s e s o f 181 number correct for both tasks under the Comprehension and Imitation Procedures, Group 2-3 performing poorer than Group 4-5. On Tasks 1 and 2 Syntax and Embeddedness were significant factors under Imitation but not Comprehension. On the Task 1 Imitation Procedure, a Simple > Relative ordering of mean number correct was obtained, a finding consistent with predictions from both hypotheses. On Task 2, however, the obtained Adjective > Simple > Relative ordering of means was consistent with the predictions made from the Depth Hypothesis only. Adjective sentences were expected to be most d i f f i c u l t , not least, according to the Trans-formation Hypothesis. The finding of poorer performance on self-embedded Relative sentences than on end-embedded or control Simple sentences on Tasks 1 and 2 under Imitation was also consistent with only the Depth Hypothesis, the Transformation Hypothesis predicting no differences since the sentences did not d i f f e r in type or number of transformations. Latency was found to be more sensitive than number correct to Syn-tax differences on Comprehension. Relative sentences were found to require significantly longer to comprehend than Simple or Adjective (Task 2). The Syntax effect was significant only for Group 2-3 on Task 2. The obtained Simple < Relative ordering of latency means was consistent with predictions made from both hypotheses. Pronoun Use was found to be a significant factor under Imitation but not Comprehension (number correct). Sentences in which the relative pronoun served as object of the preposition of the relative clause proved more d i f f i c u l t to imitate than those in which the pronoun served as ob-ject of the relative clause or as subject of the relative clause. These results were consistent with neither hypothesis. Type of adjective was found to be a significant factor for the Task 2 Comprehension but not Imitation Procedure, performance on Base 182 adjective sentences poorer than on Derived particularly for Group 2-3. The effect was attributed to vocabulary deficiency. Results of the Comprehension and Imitation Procedures allowed for ordering of means according to d i f f i c u l t y but revealed l i t t l e about the early form of knowledge of single- or multiple-word modifiers. Qualita-tive analysis of Imitation errors and Spontaneous Production data, how-ever, revealed the following. F i r s t , i t was found that prior to the occurrence of the relative clause in spontaneous speech NP + with + NP and NP + participle phrase were frequently occurring multiple-word modi-f i e r s . Second, the relative clause was used by Group 2-3 Ss but even the oldest Ss showed l i t t l e differentiation of the relative pronoun. The lack of differentiation was also evident in the substitution errors made in Imitation. Subjects tended to produce one pronoun predominately, what or that. Explanations for the lack of differentiation were discuss-ed. Third, self-embedded sentences never occurred in the Spontaneous Production protocols, an observation consistent with the high error rate on self-embedded Relative sentences under Imitation and consistent with mean depths. Fourth, the sequence of emergence of the relative clause and adjective structures in spontaneous speech was not as expected on the basis of the Transformation Hypothesis. Relative clause sentences followed rather than preceded comparable adjective sentences. Finally, few errors were made In imitation of Adjective sentences or in spontan-eous production suggesting that Ss as young as three years have already acquired productive rules covering at least some single-word modifiers. It was concluded that neither the Depth nor Transformation Hypothe-sis allowed for adequate description or prediction of performance. The Depth Hypothesis ignores the relationship between sentences of differing structure and the Transformation model f a i l s to take into account the 183 sequential nature of production and comprehension. Features of a more adequate model were discussed. 184 References Bellugi, U. The emergence of Inflections and negative systems in the speech of two children. Paper presented at New England Psychological Association, 1964. Bellugi, U. The development of interrogative structure in child-ren's speech. In K. Riegel (Ed.), The Development of Language  Functions. Developmental Program Report No. 8, 1965. Braine, M. The ontogeny of English phrase structure. The f i r s t phrase. Language, 1963, 39, 1-13. Brown, R. The development of Wh questions in child speech. Journal of Verbal Learning and Verbal Behavior, 1968, 7, 279-290. Brown, R. and Bellugi, U. Three processes in the child's acquisi-tion of syntax. Harvard Education Review, 1964, 34, 133-151. Brown, R. and Fraser, C. The acquisition of syntax. In C. Cofer and B. Musgrave (Eds.), Verbal Behavior and Learning. New York: McGraw-Hill, 1963. Brown, R. and Fraser, C. The acquisition of syntax. In U. Bellugi and R. Brown (Eds.), The acquisition of language. Monographs  of the Society for Research in Child Development, 1964, 29, 43-79. Brown, R., Fraser, C , and Bellugi, U. Explorations in grammar evaluation. In U. Bellugi and R. Brown (Eds.), The acquisi-tion of language. Monographs of the Society for Research in  Child Development, 1964, 29, 39-91. Bruner, J. The course of cognitive growth. American Psychologist, 1964, 19, 1-15. Chomsky, N. Syntactic Structures. The Hague: Mouton & Co., 1957. Chomsky, N. Formal discussion. In U. Bellugi and R. Brown (Eds.), The acquisition of language. Monographs of the Society for  Research in Child Development, 1964, 29, 35-39. Chomsky, N. Aspects of the Theory of Language. Cambridge, Mass.: M.I.T. Press, 1965. Clifton, C. and Odom, P. Similarity relations among certain Eng-l i s h sentence constructions. Psychological Monographs, 1966, 80, Whole No. 613, 1-35. Clifton, C., Kurcz, I., and Jenkins, J. Grammatical relations as determinants of sentence similarity. Journal of Verbal  Learning and Verbal Behavior, 1965, 4, 112-117. Cronbach, L. Essentials of Psychological Testing. New York: Harper, 1960. 185 Dineen, F. An Introduction to General Linguistics. New York: Holt, 1967. Dixon, T. and Horton, D. Verbal Behavior and General Behavior Theory. Englewood C l i f f s , New Jersey: Prentice-Hall, 1968. Emery, D. Sentence Analysis. New York: Holt, 1961. Fant, G. Auditory patterns of speech. In W. Wathen-Dunn (Ed.), Models for the Perception of Speech and Visual Form. Cam-bridge, Mass.: M.I.T. Press, 1967. Fla v e l l , J. The Developmental Psychology of Jean Piaget. Prince-ton, New Jersey: Van Nostrand, 1963. Fodor, J . How to learn to talk: Some simple ways. In F. Smith and G. Miller (Eds.), The Genesis of Language. Cambridge, Mass.: M.I.T. Press, 1966. Fodor, J . and Bever, T. The psychological reality of linguistic segments. Journal of Verbal Learning and Verbal Behavior, 1965, 4, 414-420. Forster, K. Left-to-right processes in the construction of sen-tences . Journal of Verbal Learning and Verbal Behavior, 1966, 5, 285-291. Forster, K. Sentence completion latencies as a function of con-stituent structure. Journal of Verbal Learning and Verbal  Behavior, 1967, 6, 878-883. Forster, K. Sentence completion in l e f t - and right-branching languages. Journal of Verbal Learning and Verbal Behavior, 1968, I, 296-299. Eraser, C , Bellugl, U., and Brown, H. Control of grammar in imitation, comprehension, and production. Journal of Verbal  Learning and Verbal Behavior, 1963, 2_, 121-135. Gaer, E. Children's understanding and production of sentences. Journal of Verbal Learning and Verbal Behavior, 1969, 8, 289-294. Garrett, M., Bever, T., and Fodor, J. The active use of grammar in speech perception. Perception and Psychophysics, 1966, 1, 30-32. Gough, P. Grammatical transformations and speed of understanding. Journal of Verbal Learning and Verbal Behavior, 1965, 4_, 107-111. Gough, P. The verification of sentences: The effects of delay of evidence and sentence length. Journal of Verbal Learning and  Verbal Behavior, 1966, 5, 492-496. 186 Greenberg, J. (Ed.), Universals in Language. Cambridge, Mass.: M.I.T. Press, 1963. Harris, Z. Co-occurrence and transformation in li n g u i s t i c struc-ture. Language. 1957, 33, 283-340. Herriot, P. The comprehension of syntax. Child Development, 1968, 39, 273-282. Herriot, P. The comprehension of active and passive sentences as a function of pragmatic expectations. Journal of Verbal  Learning and Verbal Behavior, 1969, 8, 166-169. Hunt, K. Grammatical Structures Written at Three Grade Levels. National Council of Teachers of English Research Report No. 3, Champaign, 111., 1965. Johnson, N. The psychological reality of phrase-structure rules. Journal of Verbal Learning and Verbal Behavior, 1965, 4_, 469-475. Johnson, N. The influence of grammatical units on learning. Journal of Verbal Learning and Verbal Behavior, 1968, T_, 236-240. Lashley, K. The problem of s e r i a l order in behavior. In L. A. Jeffress (Ed.), Cerebral Mechanisms in Behavior. New York: Wiley, 1951. Lenneberg, E. The Biological Basis of Language. New York: Wiley, 1967. Lovell, K. and Dixon, E. The growth of the control of grammar in imitation, comprehension, and production. Journal of Child  Psychology and Psychiatry, 1967, 8, 31-39. McCarthy, D. Language development in children. In L. Carmichael (Ed.), Manual of Child Psychology. New York: Wiley, 1954. McNeill, D. Developmental Psycholinguistles. In F. Smith and G. Miller (Eds.), The Genesis of Language. Cambridge, Mass.: M.I.T. Press, 1966.' McNeill, D. Production and perception: The view from language. Ontario Journal of Educational Pvesearch, 1968, 10, 181-185. Martin, E. and Roberts, K. Grammatical factors in sentence reten-tion. Journal of Verbal Learning and Verbal Behavior, 1966, 5, 211-218. Martin, E. and Roberts, K. Sentence length and sentence retention in the gree learning situation. Psychonomic Science, 1967, 8, 535. 187 Martin, E., Roberts, K., and Collins, A. Short-term memory of sentences. Journal of Verbal Learning and Verbal Behavior, 1968, 2» 560-566. Mehler, J. Some effects of grammatical transformations on the reca l l of English sentences. Journal of Verbal Learning and  Verbal Behavior. 1963, 2, 346-351. Mehler, J. and Miller, G. Retroactive interference in the recall of simple sentences. British Journal of Psychology, 1964, 55, 295-301. Menyuk, P. A preliminary evaluation of grammatical capacity in children. Journal of Verbal Learning and Verbal Behavior, 1963, 2, 429-439. Menyuk, P. Alternation of rules in children's grammar. Journal  of Verbal Learning and Verbal Behavior, 1964, 3> 480-488. Menyuk, P. Sentences Children Use. Cambridge, Mass.; M.I.T. Press, 1969. Miller, G. The magical number seven pluss or minus two: Some limits on our capacity for processing information. Psycho- logical Review. 1956, 63, 81-97. Miller, G. Some psychological studies of grammar. American  Psychologist. 1962, 17, 748-762. Miller, G. Some preliminaries to psycholinguistics. American  Psychologist, 1965, 20, 15-20. Miller, G. and Chomsky, N. Finitary models of language users. In R. Luce, R. Bush, and E. Galanter (Eds.), Handbook of Mathematical Psychology, Volume II. New York: Wiley, 1963. Miller, G., Galanter, E., and Pribram, K. Plans and the Structure  of Behavior. New York: Holt, 1960. Miller, G. and Isard, S. Some perceptual consequences of linguis-t i c rules. Journal of Verbal Learning and Verbal Behavior, 1963, 2, 217-228. Miller, W. and Ervin, S. The development of grammar in child language. In U. Bellugi and R. Brown (Eds.), The acquisition of language. Monographs of the Society for Research in Child  Development, 1964, 29, 9-34. Morton, J. and Broadbent, D. Passive versus active recognition models, or i s your homunculus really necessary? In W. Wathen-Dunn (Ed.), Models for the Perception of Speech and Visual Form. Cambridge, Mass.: M.I.T. Press, 1967 Neisser, U. Cognitive Psychology. New York: Appleton, 1967. 188 Piaget, J. The Origins of Intelligence in Children. New York: International Universities Press, 1952. Perfetti, C. Sentence retention and the depth hypothesis, Journal  of Verbal Learning and Verbal Behavior, 1969, 8, 101-104. Prentice, J. Response strength of single words as an influence in sentence behavior. Journal of Verbal Learning and Verbal  Behavior, 1966, 5_, 429-433. Roberts, K. Grammatical and associative constraints i n sentence retention. Journal of Verbal Learning and Verbal Behavior, 1968, 2» 1072-1076. Roberts, P. English Syntax. New York: Hartcourt, 1964. Rohrman, N. The role of syntactic structure in the r e c a l l of English nomlnalization8. Journal of Verbal Learning and  Verbal Behavior. 1968, 2» 904-912. Savin, J. and Perchonock, E. Grammatical structure and the immedi-ate r e c a l l of English sentences. Journal of Verbal Learning  and Verbal Behavior. 1965, 4, 348-353. Scholes, R. The role of grammaticality in the imitation of word strings by children and adults. Journal of Verbal Learning  and Verbal Behavior. 1969, 8, 225-228. Smith, P. and Miller, G. The Genesis of Language. Cambridge, Mass.: M.I.T. Press, 1966. Slobin, D. Grammatical transformations and sentence comprehension in childhood and adulthood. Journal of Verbal Learning and  Verbal Behavior. 1966, 5, 219-227. Staats, A. Learning, Language, and Cognition. New York: Holt, Taylor, I. Content and structure i n sentence production. Journal  of Verbal Learning and Verbal Behavior, 1969, 8, 170-175. Thomas, 0. Transformational Grammar and the Teacher of English. Hew York: Holt, 1965. Turner, E. and Rommetveit, R. Focus of attention i n r e c a l l of active and passive sentences. Journal of Verbal Learning and  Verbal Behavior, 1968, J7» 543-548. Vygotsky, L. Thought and Language. Cambridge, Mass.: M.I.T. Press, 1962. Werner, H. Comparative Psychology of Mental Development. Chicago: Follet, 1948. 189 Winer, B. S t a t i s t i c a l Principles ln Experimental Design. New York: McGraw-Hill, 1962. Yngve, V. A model and a hypothesis for language structure. Proceedings of the American Philosophical Society, 1960, 104, 444-466. Yngve, V. The depth hypothesis. Proceedings of Symposia in  Applied Mathematics, 1964i 12, 130-138. Appendix A Task 1 and Task 2 Sentences Task 1 Relative Clause Sentences There Is the boy who s i t s on the box. There i s the g i r l who s i t s on the box. There i s the boy who s i t s on the b a l l . There i s the g i r l who s i t s on the b a l l . There i s the dog that the l i t t l e boy pets. There Is the cat that the l i t t l e boy pets. There i s the dog that the l i t t l e g i r l pets. There i s the cat that the l i t t l e g i r l pets. There i s the box on which the boy s i t s . There i s the b a l l on which the boy s i t s . There i s the box on which the g i r l s i t s . There i s the b a l l on which the g i r l s i t s . The boy pets the dog that s i t s on the box. The boy pets the dog that s i t s on the b a l l . The g i r l pets the dog that si t s on the box. The g i r l pets the dog that s i t s on the b a l l . The dog s i t s on the box that the boy holds. The cat s i t s on the box that the boy holds. The dog s i t s on the box that the g i r l holds. The cat s i t s on the box that the g i r l holds. The boy holds the b a l l on which the dog s i t s . The g i r l holds the b a l l on which the dog s i t s . The boy holds the b a l l on which the cat s i t s . The g i r l holds the b a l l on which the cat s i t s . The g i r l who s i t s on the box pets the dog. The g i r l who s i t s on the b a l l pets the dog. The g i r l who s i t s on the box pets the cat. The g i r l Who s i t s on the b a l l pets the cat. The g i r l on whom the dog jumps holds the b a l l . The g i r l on whom the cat jumps holds the box. The g i r l on whom the dog jumps holds the box. The g i r l on whom the cat jumps holds the b a l l . Task 1 Simple Sentences There Is a boy. The boy s i t s on the box. There i s a g i r l . The g i r l s i t s on the box. There i s a boy. The boy s i t s on the b a l l . There i s a g i r l . The g i r l s i t s on the b a l l . There Is a dog. The l i t t l e boy pets the dog. There i s a cat. The l i t t l e boy pets the cat. There i s a dog. The l i t t l e g i r l pets the dog. There i s a cat. The l i t t l e g i r l pets the cat. There i s a box. The boy s i t s on the box. There i s a b a l l . The boy s i t s on the b a l l . There is a box. The g i r l s i t s on the box. There i s a b a l l . The g i r l s i t s on the b a l l . The boy pets the dog. The boy pets the dog. The g i r l pets the dog. The g i r l pets the dog. The dog s i t s on the box. The dog s i t s on the b a l l . The dog s i t s on the box. The dog s i t s on the b a l l . The dog s i t s on the box. The cat s i t s on the box. The dog s i t s on the box. The cat s i t s on the box. The boy holds the box. The boy holds the box. The g i r l holds the box. The g i r l holds the box. The boy holds the b a l l . The dog s i t s on the b a l l . The g i r l holds the b a l l . The dog s i t s on the b a l l . The boy holds the b a l l . The cat s i t s on the b a l l . The g i r l holds the b a l l . The cat s i t s on the b a l l . The g i r l pets the dog. The g i r l pets the dog. The g i r l pets the cat. The g i r l pets the cat. The g i r l s i t s on the box. The g i r l s i t s on the b a l l . The g i r l s i t s on the box. The g i r l s i t s on the b a l l . The dog s i t s on the box. The boy pets the dog. The dog s i t s on the b a l l . The boy pets the dog. The dog sit s on the box. The g i r l pets the dog. The dog sit s on the b a l l . The g i r l pets the dog. The g i r l holds the b a l l . The dog jumps on the g i r l . The g i r l holds the box. The cat jumps on the g i r l . The g i r l holds the box. The dog jumps on the g i r l . The g i r l holds the b a l l . The cat jumps on the g i r l . Task 2 Base Relative Sentences There i s a basket that i s l i t t l e . There i s a basket that i s big. There i s a basket that i s blue. There i s a basket that i s red. There i s a basket that i s round. There i s a basket that i s square. There i s a boy who i s sad. There i s a boy who i s happy. There i s a boy who i s short. There i s a boy who i s t a l l . There i s a boy who i s f a t . There i s a boy who i s thin. The basket that i s l i t t l e holds the apples. The basket that i s big holds the apples. The basket that i s blue holds the apples. The basket that i s red holds the apples. The basket that i s round holds the apples. The basket that i s square holds the apples. The boy who i s sad holds the apples. The boy who i s happy holds the apples. The boy who i s short holds the apples. The boy who i s t a l l holds the apples. The boy who i s fat holds the apples. The boy who i s thin holds the apples. The dog sees the basket that i s l i t t l e . The dog sees the basket that i s big. The dog sees the basket that i s blue. The dog sees the basket that i s red. The dog sees the basket that i s round. The dog sees the basket that i s square. The dog sees the boy who i s sad. The dog sees the boy who i s happy. The dog sees the boy who i s short. The dog sees the boy who i s t a l l . The dog sees the boy who i s fat. The dog sees the boy who i s thin. The dog looks at the The dog looks at the The dog looks at the' The dog looks at the The dog looks at the The dog looks at the The dog looks at the The dog looks at the The dog looks at the The dog looks at the The dog looks at the The dog looks at the basket that i s l i t t l e , basket that i s big. basket that i s blue, basket that i s red. basket that i s round, basket that i s square, boy who i s sad. boy who i s happy, boy who i s short, boy who i s t a l l , boy who i s fat. boy who i s thin. 194 Task 2 Derived Relative Sentences There Is a boy who i s fishing. There le a boy who i s swimming.. There Is a boy who is standing. There Is a boy who i s si t t i n g . There Is a boy who i s climbing. There Is a boy who i s f a l l i n g . There Is a g i r l who i s crying. There i s a g i r l who i s laughing. There i s a g i r l who i s sleeping. There i s a g i r l who i s playing. There Is a g i r l who i s running. There i s a g i r l who i s walking. S The boy who i s fishing holds the bear. The boy who i s swimming holds the bear. The boy who i s standing holds the bear. The boy who i s si t t i n g holds the bear. The boy who i s climbing holds the bear. The boy who i s f a l l i n g holds the bear. The g i r l who i s crying holds the bear. The g i r l who i s laughing holds the bear. The g i r l who i s sleeping holds the bear. The g i r l who i s playing holds the bear. The g i r l who i s running holds the bear. The g i r l who i s walking holds the bear. 0 The dog sees the boy who i s fishing. The dog sees the boy who i s swimming. The dog sees the boy who i s standing. The dog sees the boy who i s s i t t i n g . The dog sees the boy who i s climbing. The dog sees the boy who i s f a l l i n g . The dog sees the g i r l who i s crying. The dog sees the g i r l who i s laughing. The dog sees the g i r l who i s sleeping. The dog sees the g r i l who i s playing. The dog sees the g i r l who i s running. The dog sees the g i r l who i s walking. P The dog looks at The dog looks at The dog looks at The dog looks at The dog looks at The dog looks at The dog looks at The dog looks at The dog looks at The dog looks at The dog looks at The dog looks at the boy who i s fishing, the boy who i s swimming, the boy who i s standing, the boy who i s si t t i n g , the boy who i s climbing, the boy who i s f a l l i n g , the g i r l who i s crying, the g i r l who i s laughing, the g i r l who i s sleeping, the g i r l who i s playing, the g i r l who i s running, the g i r l who i s walking. Task 2 Base Simple Sentences There There There There There There There There There There There There Is a Is a Is a Is a Is a is a Is a Is a Is a Is a Is a Is a basket. The basket Is l i t t l e , basket. The basket Is big. basket. The basket Is blue, basket. The basket Is red. basket. The basket i s round, basket. The basket Is square, boy. The boy i s sad. boy. The boy Is happy, boy. The boy i s short, boy. The boy i s t a l l , boy. The boy Is fat. boy. The boy i s thin. The basket holds the apples. The basket holds the apples. The basket holds the apples. The basket holds the apples. The basket holds the apples. The basket holds the apples. The boy holds the apples. The boy holds the apples. The boy holds the apples. The boy holds the apples. The boy holds the apples. The boy holds the apples. The basket i s l i t t l e . The basket i s big. The basket i s blue. The basket i s red. The basket i s round. The basket i s square. The boy i s sad. The boy i s happy. The boy i s short. The boy i s t a l l . The boy i s fat. The boy i s thin. The dog sees the basket. The basket i s l i t t l e . The dog sees the basket. The basket i s big. The dog sees the basket. The basket i s blue. The dog sees the basket. The basket i s red. The dog sees the basket. The basket i s round. The dog sees the basket. The basket i s square. The dog sees the boy. The boy i s sad. The dog sees the boy. The boy i s happy. The dog sees the boy. The boy i s short. The dog sees the boy. The boy i s t a l l . The dog sees the boy. The boy i s fat. The dog sees the boy. The boy i s thin. The dog looks at the basket. The basket i s l i t t l e . The dog looks at the basket. The basket i s big. The dog looks at the basket. The basket i s blue. The dog looks at the basket. The basket i s red. The dog looks at the basket. The basket i s round. The dog looks at the basket. The basket i s square. The dog looks at the boy. The boy i s sad. The dog looks at the boy. The boy i s happy. The dog looks at the boy. The boy i s short. The dog looks at the boy. The boy i s t a l l . The dog looks at the boy. The boy i s fat. The dog looks at the boy. The boy i s thin. Task 2 Derived Simple Sentences There i s a boy. The boy Is fishing. There is a boy. The boy i s swimming. There i s a boy. The boy i s standing. There i s a boy. The boy i s s i t t i n g . There is a boy. The boy i s climbing. There i s a boy. The boy i s f a l l i n g . There i s a g i r l . The g i r l i s crying. There i s a g i r l . The g i r l i s laughing. There i s a g i r l . The g i r l i s sleeping. There i s a g i r l . The g i r l i s playing. There is a g i r l . The g i r l i s running. There is a g i r l . The g i r l i s walking. The boy holds the bear. The boy i s The boy holds the bear. The boy Is The boy holds the bear. The boy i s The boy holds the bear. The boy i s The boy holds the bear. The boy i s The boy holds the bear. The boy i s The g i r l holds the bear. The g i r l The g i r l holds the bear. The g i r l The g i r l holds the bear. The g i r l The g i r l holds the bear. The g i r l The g i r l holds the bear. The g i r l The g i r l holds the bear. The g i r l fishing. swimming. standing. s i t t i n g . climbing. f a l l i n g , i s crying, i s laughing, i s sleeping, i s playing, i s running, i s walking. The dog The dog The dog The dog The dog The dog The dog The dog The dog The dog The dog The dog The dog The dog The dog The dog The dog The dog The dog The dog The dog The dog The dog The dog sees sees sees sees sees sees sees sees sees sees sees sees the boy. the boy. the boy. the boy. the boy. the boy. the g i r l , the g i r l , the g i r l , the g i r l , the g i r l , the g i r l . i s The boy i s The boy i s The boy i s The boy i s The boy i s The boy The g i r l The g i r l The g i r l The g i r l The g i r l The g i r l fishing, swimming, standing, si t t i n g , climbing, f a l l i n g . Is crying, i s laughing, i s sleeping, i s playing, i s running, i s walking. looks looks looks looks looks looks looks looks looks looks looks looks at the at the at the at the at the at the at the at the at the at the at the at the boy. boy. boy. boy. boy. boy. g i r l . g i r l . g i r l . g i r l . g i r l , g i r l . The boy Is The boy i s The boy i s The boy i s The boy i s The boy i s The g i r l The g i r l The g i r l The g i r l The g i r l The g i r l fishing. swimming. standing. s i t t i n g . climbing. f a l l i n g , i s crying, i s laughing, is sleeping, i s playing, i s running, i s walking. 197 Task 2 Base Adjective Sentences There i s a l i t t l e basket. There i s a big basket. There i s a blue basket. There Is a red basket. There i s a round basket. There Is a square basket. There i s a sad boy. There Is a happy boy. There i s a short boy. There Is a t a l l boy. There i s a fat boy. There i s a thin boy. The l i t t l e basket holds the apples. The big basket holds the apples. The blue basket holds the apples. The red basket holds the apples. The round basket holds the apples. The square basket holds the apples. The sad boy holds the apples. The happy boy holds the apples. The short boy holds the apples. The t a l l boy holds the apples. The fat boy holds the apples. The thin boy holds the apples. 0 The dog sees the The dog sees the The dog sees the The dog sees the The dog sees the The dog sees the The dog sees the The dog sees the The dog sees the The dog sees the The dog sees the The dog sees the l i t t l e basket, big basket, blue basket, red basket, round basket, square basket, sad boy. happy boy. short boy. t a l l boy. fat boy. thin boy. F The dog looks at the l i t t l e basket. The dog looks at the big basket. The dog looks at the blue basket. The dog looks at the red basket. The dog looks at the round basket. The dog looks at the square basket. The dog looks at the sad boy. The dog looks at the happy boy. The dog looks at the short boy. The dog looks at the t a l l boy. The dog looks at the fat boy. The dog looks at the thin boy. Task 2 Derived Adjective Sentences There is a fishing boy. There i s a swimming boy. There i s a standing boy. There i s a s i t t i n g boy. There i s a climbing boy. There i s a f a l l i n g boy. There i s a crying g i r l . There i s a laughing g i r l . There is a sleeping g i r l . There i s a playing g i r l . There i s a running g i r l . There is a walking g i r l . The fishing boy holds the bear. The swimming boy holds the bear. The standing boy holds the bear. The s i t t i n g boy holds the bear. The climbing boy holds the bear. The f a l l i n g boy holds the bear. The crying g i r l holds the bear. The laughing g i r l holds the bear. The sleeping g i r l holds the bear. The playing g i r l holds the bear. The running g i r l holds the bear. The walking g i r l holds the bear. The dog sees the fishing boy. The dog sees the swimming boy. The dog sees the standing boy. The dog sees the si t t i n g boy. The dog sees the climbing boy. The dog sees the f a l l i n g boy. The dog sees the crying g i r l . The dog sees the laughing g i r l . The dog sees the sleeping g i r l . The dog sees the playing g i r l . The dog sees the running g i r l . The dog sees the walking g i r l . The dog looks at The dog looks at The dog looks at The dog looks at The dog looks at The dog looks at The dog looks at The dog looks at The dog looks at The dog looks at The dog looks at The dog looks at the fishing boy. the swimming boy. the standing boy. the s i t t i n g boy. the climbing boy. the f a l l i n g boy. the crying g i r l , the laughing g i r l , the sleeping g i r l , the playing g i r l , the running g i r l , the walking g i r l . Appendix B Sample Task 1 and Task 2 Pictures 200 201 204 207 

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