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Implicit and explicit memory in preschoolers Buller, Terri 1990

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IMPLICIT AND EXPLICIT MEMORY IN PRESCHOOLERS By T e r r i B u l l e r B . S C , U n i v e r s i t y of V i c t o r i a , 1988 A THESIS SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF ARTS i n THE FACULTY OF GRADUATE STUDIES (Department of Psychology) We accept t h i s t h e s i s as conforming t o the r e q u i r e d standard THE UNIVERSITY OF BRITISH COLUMBIA J u l y 1990 © T e r r i B u l l e r , 1990 In presenting this thesis in partial fulfilment of the requirements for an advanced degree at the University of British Columbia, I agree that the Library shall make it freely available for reference and study. I further agree that permission for extensive copying of this thesis for scholarly purposes may be granted by the head of my department or by his or her representatives. It is understood that copying or publication of this thesis for financial gain shall not be allowed without my written permission. Department of P j b ^ c A ^ l ^ p A ^ The University of British Columbia Vancouver, Canada Date DE-6 (2/88) ABSTRACT E x p l i c i t memory r e f e r s t o conscious or d e l i b e r a t e r e c o l l e c t i o n of r e c e n t events and experiences, whereas i m p l i c i t memory i s r e v e a l e d when the same events and experiences a f f e c t performance i n the absence of conscious r e c o l l e c t i o n . I t i s w e l l known t h a t i m p l i c i t and e x p l i c i t memory develop d i f f e r e n t l y a c r o s s the l i f e span: E x p l i c i t memory i s a c q u i r e d i n e a r l y c h i l d h o o d , remains s t a b l e a c r o s s adulthood, and then decreases i n l a t e r l i f e , whereas i m p l i c i t memory develops e a r l i e r i n c h i l d h o o d and remains i n t a c t w e l l i n t o l a t e adulthood ( f o r review see Graf, 1990). To e x p l a i n t h i s p a t t e r n of r e s u l t s , i t has been suggested t h a t i m p l i c i t memory performance i s mediated by automatic p r o c e s s i n g , whereas e x p l i c i t memory performance i s mediated by s u b j e c t c o n t r o l l e d p r o c e s s i n g , such as g o a l s and s t r a t e g i e s (e.g., C r a i k , 1983). My t h e s i s examines whether development d u r i n g the p r e s c h o o l y e a r s has the same e f f e c t or d i f f e r e n t e f f e c t s on i m p l i c i t and e x p l i c i t memory t e s t performance. Toward t h i s g o a l , I f i r s t c o l l e c t e d normative data t o e s t a b l i s h baserate performance on category p r o d u c t i o n t e s t s f o r use i n the main experiment. S u b j e c t s c o n s i s t e d of 96 p r e s c h o o l e r s and p r o d u c t i o n norms were gathered f o r 7 d i f f e r e n t c a t e g o r i e s . The procedure i n v o l v e d r e a d i n g a b r i e f s t o r y t o focus s u b j e c t s a t t e n t i o n on a category and r e q u i r e d them t o name 5 items from t h a t c a t e g o r y . T e s t performance showed two n o t a b l e f i n d i n g s . F i r s t , some c a t e g o r i e s had a more gradual d r o p - o f f i n response r a t e d i s t r i b u t i o n s than o t h e r s , and second, d i f f e r e n c e s i n response r a t e s f o r the d i f f e r e n t age groups were g r e a t e r i n i i i some c a t e g o r i e s than o t h e r s . The main p a r t of t h i s t h e s i s i s an experiment t h a t examined whether development has the same e f f e c t o r d i f f e r e n t e f f e c t s on i m p l i c i t and e x p l i c i t memory t e s t performance. Subjects f o r t h i s study c o n s i s t e d of groups of 12 3-, 4 - , and 5-year o l d s (n=36). The method i n v o l v e d p r e s e n t i n g s u b j e c t s with category p r o d u c t i o n and category c u e d - r e c a l l t e s t s f o r p r e v i o u s l y s t u d i e d items. The items were s e l e c t e d from the norms a c c o r d i n g t o th r e e c r i t e r i a : frequency of occurrence i n the norms was not a t f l o o r or c e i l i n g , occurrence f r e q u e n c i e s were s i m i l a r a c r o s s age groups, and each item was r e p r e s e n t a b l e as a p i c t u r e . During the study phase f i v e items were s t u d i e d from each of 4 c a t e g o r i e s : CLOTHES, TRAVEL, PLAYGROUND, and ZOO. Ten of the 20 items (5 per category) were s t u d i e d by each s u b j e c t — 5 i n a n o n - e l a b o r a t i v e study c o n d i t i o n t h a t r e q u i r e d s u b j e c t s t o name each item and 5 i n an e l a b o r a t i v e study c o n d i t i o n t h a t asked them t o name each item and answer a q u e s t i o n about r e a l -l i f e aspects/uses of the item (e.g., "Do boys wear d r e s s e s ? " ) . Two s e t s of t a r g e t items t h a t were not s t u d i e d were used t o assess baserate performance. The t e s t i n g phase o c c u r r e d immediately a f t e r the study phase. I m p l i c i t memory performance was assessed with category production t e s t s u s i n g the same procedure as f o r the norms study. E x p l i c i t memory was assessed with a category cued-r e c a l l t e s t . The c r i t i c a l f i n d i n g s from the i m p l i c i t memory t e s t s were: more priming i n the e l a b o r a t i v e than i n the non-e l a b o r a t i v e study c o n d i t i o n s , and s i m i l a r l y l a r g e priming e f f e c t s a c r o s s age-groups. The e x p l i c i t memory t e s t r e s u l t s showed t h a t performance i n c r e a s e d across age-groups, but only f o r m a t e r i a l s i n the n o n - e l a b o r a t i v e study c o n d i t i o n . In the e l a b o r a t i v e study c o n d i t i o n 3-year o l d s ' performance was comparable t o t h a t of the 5-year o l d s . The p r e s e n t t h e s i s i l l u s t r a t e d the d i s t i n c t i o n between i m p l i c i t and e x p l i c i t memory performance. Furthermore, i t supports the h y p o t h e s i s t h a t while there i s o v e r l a p o f some of the components media t i n g these forms of memory, p a r t i c u l a r l y r e l a t e d t o s t o r a g e of m a t e r i a l s , there are s i g n i f i c a n t d i f f e r e n c e s between other mediating processes of i m p l i c i t and e x p l i c i t memory t h a t are more c l o s e l y a s s o c i a t e d w i t h r e t r i e v a l of m a t e r i a l s . V TABLE OF CONTENTS A b s t r a c t i i Table of Contents v L i s t of Tables v i L i s t of F i g u r e s v i i Acknowledgement v i i i Chapter 1: I n t r o d u c t i o n 1 Chapter 2: I m p l i c i t and E x p l i c i t Memory — Research and Theory 8 Chapter 3: Study 1 — Pr e s c h o o l C h i l d r e n ' s Word Pro d u c t i o n s For Seven C a t e g o r i e s 34 Chapter 4: Study 2 — I m p l i c i t and E x p l i c i t memory i n p r e s c h o o l e r s : When 3-year o l d s remember as much as 5-year o l d s 64 Chapter 5: D i s c u s s i o n 81 References 92 Appendix A: Category S t o r i e s and Questions.... 96 Appendix B: A n a l y s i s o f Va r i a n c e Tables f o r Normative Study 99 Appendix C ( L i s t 1): A l p h a b e t i c a l Ordered Category P r o d u c t i o n Norms 101 Appendix C ( L i s t 2): Numerical Ordered Category P r o d u c t i o n Norms 116 Appendix D: Category P r o d u c t i o n Histographs. . . 131 Appendix E: Category L i n e Drawings and E l a b o r a t i v e Study C o n d i t i o n Questions 135 Appendix F: A n a l y s i s of V a r i a n c e Tables f o r the Main Experiment 143 v i LIST OF TABLES Table 1: Number of Subjects per Age-group Tested i n Each C o n d i t i o n 36 Table 2: The Mean Number of Items Named per C h i l d f o r Each Category 40 Table 3: The Mean Number of D i f f e r e n t Items Named f o r Each Category 42 Table 4: D i f f e r e n c e s Between The Mean Number of D i f f e r e n t Responses Produced per Category 43 Table 5: C o r r e l a t i o n C o e f f i c i e n t s For Each Category and Age-group P a i r Based on the P r o p o r t i o n of Sub j e c t s That Named Each Item 45 Table 6: Index of Commonality Values For Each Age-group and For Each Category 48 Table 7: Tukey Comparisons: D i f f e r e n c e s i n Index of Commonality R a t i o s f o r Each P a i r of C a t e g o r i e s 49 Table 8: Type/Token R a t i o s For C a t e g o r i e s and Across Age-groups 51 Table 9: Tukey Comparisons: Mean D i f f e r e n c e i n Type/Token R a t i o s For Each P a i r of C a t e g o r i e s . . . . 52 Table 10: T y p i c a l i t y / D i v e r s i t y R a t i o s For C a t e g o r i e s and Across Age-groups 55 Table 11: Tukey Comparisons: Mean D i f f e r e n c e s i n T y p i c a l i t y / D i v e r s i t y R a t i o s For Each P a i r o f C a t e g o r i e s 56 v i i LIST OF FIGURES Fi g u r e 1: Mean % of t a r g e t words produced 71 F i g u r e 2: Mean % of t a r g e t words r e c a l l e d 73 v i i i ACKNOWLEDGEMENT I would l i k e t o acknowledge the a s s i s t a n c e t h a t I r e c e i v e d from Dr. Peter Graf. His and guidance and endless p a t i e n c e was i n v a l u a b l e throughout the data c o l l e c t i o n and w r i t i n g of t h i s t h e s i s . S p e c i a l thanks goes out t o the numerous Vancouver area daycare c e n t r e s t h a t a s s i s t e d i n the g a t h e r i n g of s u b j e c t s f o r my r e s e a r c h . I would a l s o l i k e t o acknowledge the f i n a n c i a l a s s i s t a n c e from the N a t i o n a l Science and En g i n e e r i n g Research C o u n c i l t h a t supported me du r i n g my l a s t year as an M.A. student. 1 Chapter 1 INTRODUCTION When asked t o l i s t the d i f f e r e n t games p l a y e d on the sc h o o l - y a r d d u r i n g t h e i r l a s t break, c h i l d r e n ' s performance depends on the a b i l i t y t o r e c o l l e c t i n a c o n s c i o u s , d e l i b e r a t e manner i n f o r m a t i o n from a p a r t i c u l a r time and p l a c e . The phrase e x p l i c i t memory has been used t o d e s c r i b e performance i n t h i s s i t u a t i o n . In c o n t r a s t , when asked t o simply name any sc h o o l - y a r d games t h a t come to mind, performance does not depend on the c h i l d r e n ' s a b i l i t y t o r e c o l l e c t i n a conscious manner, and memory i s s a i d t o be i m p l i c i t . I m p l i c i t memory, and priming (changes i n i m p l i c i t memory), are i n d i c a t e d by performance e f f e c t s a t t r i b u t a b l e t o r e c e n t events or experiences t h a t occur i n the absence of co n s c i o u s r e c o l l e c t i o n (Graf & Schacter, 1985; Schacter & Graf, 1986). Over the p a s t few years t h e r e has been a r a p i d growth of r e s e a r c h on i m p l i c i t and e x p l i c i t memory (e.g., Graf & Schacter, 1985; Greenbaum & Graf, 1989; L i g h t & Singh, 1987; Nai t o , i n p r e s s ; P a r k i n & S t r e e t e , 1988; Schacter & Graf, 1986) and three f i n d i n g s from t h i s work motivated my t h e s i s . The f i r s t concerns the d i f f e r e n t development of i m p l i c i t and e x p l i c i t memory a c r o s s the l i f e - s p a n . S p e c i f i c a l l y , a re c e n t review by Graf (1990) suggests t h a t i m p l i c i t memory remains s t a b l e through the l i f e - s p a n while e x p l i c i t remembering changes. There i s evidence (e.g., Greenbaum & Graf, 1989) t h a t i m p l i c i t memory develops very e a r l y and may be f u l l y i n t a c t even by the t h i r d year of l i f e . However, i t i s not u n t i l about the age of 5 years t h a t e x p l i c i t memory develops. Then i t 2 increases i n t o e a r l y adulthood and then remains r e l a t i v e l y s t a b l e through the middle a d u l t years and d e c l i n e s l a t e i n the l i f e - s p a n . Greenbaum and Graf (1989) have suggested t h a t these developmental changes i n i m p l i c i t and e x p l i c i t memory.may be due t o a developmentally e a r l i e r mode of c o g n i t i v e f u n c t i o n i n g . The second f i n d i n g from the l i t e r a t u r e t h a t motivated my t h e s i s i s t h a t amnesic p a t i e n t s perform as w e l l as normals on t e s t s of i m p l i c i t memory even though they are se v e r e l y impaired on t e s t s of e x p l i c i t memory (e.g., Gardner, B o i l e r , Moreines, & Bu t t e r s , 1973; f o r review see Schacter, 1987). This f i n d i n g i l l u s t r a t e s t h a t amnesia spares the processes t h a t mediate i m p l i c i t memory, but not those t h a t mediate e x p l i c i t memory. The question t o ask here i s what i s the d i f f e r e n c e between the processes u n d e r l y i n g each of these forms of memory t h a t produces the s e l e c t i v e sparing of one i n amnesia. One p o s s i b i l i t y i s t h a t the processes mediating i m p l i c i t memory develop e a r l y and are more b a s i c than those u n d e r l y i n g e x p l i c i t memory and such b a s i c process may be more robust t o aging and syndromes such as amnesia. This k i n d of exp l a n a t i o n a l s o f i t s the developmental f i n d i n g t h a t i m p l i c i t memory i s f u l l y i n t a c t long before e x p l i c i t memory (e.g., Greenbaum & Graf, 1989). The t h i r d m o t i v a t i n g f i n d i n g from the l i t e r a t u r e i s the f a c t t h a t v a r i o u s experimental manipulations, such as l e v e l s of processing, a f f e c t i m p l i c i t and e x p l i c i t memory performance d i f f e r e n t l y . For example, Graf and Mandler (1984) found that e l a b o r a t i v e or semantic processing of study m a t e r i a l s increases performance on e x p l i c i t memory t e s t s , but i t has no e f f e c t or only a minimal e f f e c t on t e s t s of i m p l i c i t memory. In Graf and 3 Mandler's Experiment 3, s u b j e c t s s t u d i e d words e i t h e r s e m a n t i c a l l y (by r a t i n g how much they l i k e d o r d i s l i k e d each word) or non s e m a n t i c a l l y (by counting the number of e n c l o s u r e s and T - j u n c t i o n s i n each word). Then i m p l i c i t and e x p l i c i t memory were t e s t e d w i t h word-stem completion and c u e d - r e c a l l t e s t s , r e s p e c t i v e l y . The completion t e s t r e s u l t s showed s i m i l a r performance i n the semantic and nonsemantic study c o n d i t i o n s , whereas c u e d - r e c a l l performance was much hi g h e r i n the semantic study t a s k c o n d i t i o n . To e x p l a i n t h e s e r e s u l t s , Graf and Mandler (1984) have suggested t h a t i m p l i c i t memory r e l i e s on automatic processes whereas e x p l i c i t memory r e l i e s on c o n t r o l l e d processes such as f o r m u l a t i n g a r e t r i e v a l p l a n or spontaneous e l a b o r a t i o n of m a t e r i a l s . By the assumption t h a t c o n t r o l l e d or s e l f - i n i t i a t e d a b i l i t i e s are a c q u i r e d d u r i n g the preschool years, i t f o l l o w s t h a t i m p l i c i t memory can be i n t a c t even i n c h i l d r e n as young as th r e e years, w h i l e e x p l i c i t memory should i n c r e a s e d u r i n g the same p e r i o d of l i f e . At present, however, very l i t t l e r e s e a r c h has examined t h i s view of memory development. T e s t s of I m p l i c i t and E x p l i c i t Memory The extant r e s e a r c h has used a wide range of t e s t s t o assess i m p l i c i t and e x p l i c i t memory. T h i s s e c t i o n o u t l i n e s the major t e s t s t h a t have been used. Tests of i m p l i c i t memory t y p i c a l l y i n v o l v e the comparison of two d i f f e r e n t performances: baserate performance and post-study performance. Baserate performance i s how w e l l s u b j e c t s perform on a g i v e n t a s k without a p r i o r study episode, whereas post-study performance i s how w e l l a s u b j e c t performs on t h a t same t a s k a f t e r being 4 exposed t o a t a r g e t l i s t of m a t e r i a l s (such as words or p i c t u r e s ) . The d i f f e r e n c e between these two performances i n d i c a t e s the e f f e c t of the study episode on performance. T e s t s of e x p l i c i t memory t y p i c a l l y focus on post-study performance a f t e r s u b j e c t s are reminded of the study p e r i o d . Performance on i m p l i c i t and e x p l i c i t t e s t s may be assessed i n a number of d i f f e r e n t ways, w i t h both speed and accuracy measures. T h i s review focuses on accuracy measures because they have been used more e x t e n s i v e l y i n the immediately r e l e v a n t l i t e r a t u r e . I m p l i c i t Memory T e s t s I m p l i c i t memory i s o f t e n assessed i n terms of priming. Priming i s demonstrated when p r e v i o u s l y s t u d i e d items are named more o f t e n than those named i n the baserate c o n d i t i o n (performance i n the absence of p r i o r s t u d y ) . Category p r o d u c t i o n t e s t s . For category p r o d u c t i o n t e s t s s u b j e c t s are presented w i t h a category l a b e l (e.g., CLOTHES) and asked t o name any items t h a t belong t o t h i s c a t e gory. The i n s t r u c t i o n s make no r e f e r e n c e t o the p r i o r study episode and s u b j e c t s are g e n e r a l l y stopped a f t e r having named a s p e c i f i c number of items per category cue or a f t e r ceasing t o name items a f t e r a g i v e n p e r i o d of time. Word-stem completion t e s t s . For these t e s t s s u b j e c t s are presented p a r t of a word (e.g., CLO ) and i n s t r u c t e d t o e i t h e r f i l l i n or say a l o u d whatever word comes t o mind. As with category p r o d u c t i o n t e s t s , no mention i s made of the p r i o r study episode and priming i s demonstrated when s u b j e c t s complete the stems with more t a r g e t words than they would i n a 5 base r a t e c o n d i t i o n . Word-fragment completion t e s t s . Fragment completion t e s t s are very s i m i l a r t o word-stem completion t e s t s . The d i f f e r e n c e i s t h a t the cue i s a word fragment (e.g., C_OT S) i n s t e a d of the beginning of a word (e.g., CLO ). I n s t r u c t i o n s and demonstrations of priming are the same as wi t h word-stem completion t e s t s . E x p l i c i t Memory Tes t s For each of the f o l l o w i n g t e s t s s u b j e c t s are reminded of the p r i o r study episode and asked t o name items o n l y from the study s e s s i o n . Word R e c o g n i t i o n t e s t s . In word r e c o g n i t i o n t e s t s s u b j e c t s are presented with a w o r d - l i s t t h a t c o n t a i n s t a r g e t words ( p r e v i o u s l y s t u d i e d words) as w e l l as new words (unstudied words). As each word i s presented f o r t e s t i n g , s u b j e c t s are asked to say whether or not they r e c o g n i z e the word from the study l i s t . S u b j e c t s respond w i t h YES (they do re c o g n i z e the word as being from the study l i s t ) or NO (they do  not r e c o g n i z e the word from the study l i s t ) . Confidence r a t i n g s may a l s o be c o l l e c t e d with r e c o g n i t i o n t e s t s and these t y p i c a l l y i n v o l v e asking the s u b j e c t t o r a t e how sure they are of t h e i r YES/NO answer. E x p l i c i t memory performance i s i n d i c a t e d by the number of h i t s ( c o r r e c t l y r e c o g n i z e d t a r g e t words). F a l s e alarms ( i n c o r r e c t l y r e c o g n i z e d new word) may a l s o be assessed. C u e d - r e c a l l t e s t s . C u e d - r e c a l l t e s t s are very s i m i l a r t o the category p r o d u c t i o n t e s t s used f o r a s s e s s i n g i m p l i c i t memory. The important d i f f e r e n c e i s the i n s t r u c t i o n s . U n l i k e 6 category p r o d u c t i o n t e s t s , s u b j e c t s presented with a cued-r e c a l l t e s t are asked t o use the cue (e.g., a category l a b e l ) t o h e l p them r e c o l l e c t the items from the study s e s s i o n . For example, s u b j e c t s may be presented with the category l a b e l CLOTHES, informed t h a t some of the items they s t u d i e d belong t o t h i s category, and asked t o r e c o l l e c t those items. E x p l i c i t memory performance i s indexed by the number of t a r g e t words r e c a l l e d . F r e e - r e c a l l t e s t s . F r e e - r e c a l l t e s t s are d i f f e r e n t from r e c o g n i t i o n and c u e d - r e c a l l t e s t s i n t h a t no cue i s presented to the s u b j e c t . They are simply asked t o r e c o l l e c t as many items they can from the p r i o r study episode. As with the cued-r e c a l l t e s t , e x p l i c i t memory i s i n d i c a t e d by the number of t a r g e t words t h a t the s u b j e c t names. Overview The remainder of my t h e s i s i s d i v i d e d i n t o f o u r chapters. The second chapter p r o v i d e s the background and the m o t i v a t i o n f o r the t h e s i s . I t b r i e f l y reviews the extant i m p l i c i t and e x p l i c i t memory r e s e a r c h c a r r i e d out on f o u r s u b j e c t groups: Amnesic p a t i e n t s , h e a l t h y young a d u l t s , and young c h i l d r e n and o l d e r a d u l t s . The major f i n d i n g s and i m p l i c a t i o n s from these s t u d i e s are summarized and t h e o r i e s t h a t have been developed t o e x p l a i n the f i n d i n g s are reviewed. Chapter t h r e e d e s c r i b e s a study t h a t i n v o l v e d g a t h e r i n g p r o d u c t i o n norms from 3-, 4-, and 5-year o l d s . The purpose was twofold. F i r s t , the category p r o d u c t i o n norms were r e q u i r e d t o s e l e c t a p p r o p r i a t e items f o r a l l age-groups t h a t p a r t i c i p a t e d i n the main experiment (see Chapter 4). Normative data are 7 c r i t i c a l i n t h i s regard because vocabulary development i s rapid during the preschool years, and thus, I had to ensure that target items were approximately equally f a m i l i a r to a l l age-groups. The second purpose of the normative study was to establish baseline production rates for various items i n order to avoid c e i l i n g and flo o r effects on the te s t s used i n the main experiment. Chapter four i s the core of my th e s i s ; i t describes the method, r e s u l t s , and implications of an experiment that examined i m p l i c i t and e x p l i c i t memory t e s t performance i n 3 - , 4-, and 5-year olds. The overall goal was to t e s t the hypotheses that e x p l i c i t memory performance i s mediated by controlled processes that are not f u l l y developed, whereas i m p l i c i t memory i s mediated by automatic processes. F i n a l l y , chapter f i v e presents a summary of the ove r a l l findings and discusses the implications of the main experiment. In addition, suggestions are made for d i r e c t i o n s of future research. 8 Chapter 2 EXPLICIT AND IMPLICIT MEMORY: RESEARCH AND THEORY Over the past few years there has been a r a p i d growth of s t u d i e s on e x p l i c i t and i m p l i c i t memory t e s t performance. A l a r g e p o r t i o n of t h i s r e s e a r c h has focused on f o u r s u b j e c t p o p u l a t i o n s : p a t i e n t s w i t h o r g a n i c amnesia, h e a l t h y young a d u l t s , young c h i l d r e n and o l d e r a d u l t s . F i n d i n g s from the l a s t two groups are most d i r e c t l y r e l e v a n t to understanding memory development ac r o s s the l i f e - s p a n . The f i r s t s e c t i o n of t h i s chapter reviews the r e s e a r c h from these f o u r p o p u l a t i o n s , and the second s e c t i o n reviews the t h e o r e t i c a l p r o p o sals t h a t have been o f f e r e d t o e x p l a i n the major f i n d i n g s . Research Review Studie s with Amnesic P a t i e n t s A c r i t i c a l segment of the l i t e r a t u r e on e x p l i c i t and i m p l i c i t memory i n v o l v e s s t u d i e s of p a t i e n t s w i t h o r g a n i c amnesia. These s t u d i e s are important f o r two reasons: F i r s t , they provided a major impetus f o r the c u r r e n t i n t e r e s t i n performance d i s s o c i a t i o n between e x p l i c i t and i m p l i c i t memory. A second reason i s t h a t they provide r e s e a r c h e r s with a pure i l l u s t r a t i o n of i m p l i c i t memory performance because amnesics' e x p l i c i t memory i s s e v e r e l y impaired and, t h e r e f o r e , i s not l i k e l y t o contaminate i m p l i c i t memory t e s t performance. The t y p i c a l p a t t e r n of performance by amnesic p a t i e n t s i s i l l u s t r a t e d by a study o f Gardner, B o i l e r , Moreines, and B u t t e r s (1973) who examined i m p l i c i t and e x p l i c i t memory performance u s i n g a category p r o d u c t i o n and category cued-r e c a l l t e s t , r e s p e c t i v e l y . For the former t a s k , s u b j e c t s were 9 presented with category l a b e l s and asked t o name any s i x items t h a t came t o mind. For the c u e d - r e c a l l t a s k , s u b j e c t s were presented a category l a b e l and asked t o r e c o l l e c t p r e v i o u s l y s t u d i e d items b e l o n g i n g to t h a t category. The c r i t i c a l dependent measure f o r both t e s t s was the number of t a r g e t items t h a t were named. Gardner e t a l . (1973) found t h a t on the i m p l i c i t memory t e s t , amnesic p a t i e n t s performed a t the same l e v e l as the c o n t r o l s u b j e c t s . In c o n t r a s t , t h e i r e x p l i c i t memory performance showed the t y p i c a l , severe memory d e f i c i t t h a t d e f i n e s amnesia. T h i s s e l e c t i v e s p a r i n g o f i m p l i c i t memory i m p l i e s t h a t e x p l i c i t and i m p l i c i t memory must, a t l e a s t i n p a r t , depend on d i f f e r e n t u n d e r l y i n g p r o c e s s e s (see Graf & Schacter, 1985). Recent work has examined i n more d e t a i l what aspects of i m p l i c i t memory are spared i n amnesic p a t i e n t s . For t h i s purpose, i n v e s t i g a t i o n s have focused on e x p e r i m e n t a l v a r i a b l e s t h a t are known t o have d i f f e r e n t e f f e c t s on i m p l i c i t versus e x p l i c i t memory t e s t performance i n normal s u b j e c t s , i n c l u d i n g the e f f e c t s of semantic versus non-semantic study t a s k s , modality of study and t e s t l i s t p r e s e n t a t i o n , and f a m i l i a r items versus new a s s o c i a t i o n s . The f o l l o w i n g s e c t i o n b r i e f l y reviews experiments from each of these domains. L e v e l of p r o c e s s i n g a t study. One h y p o t h e s i s put f o r t h t o e x p l a i n amnesic p a t i e n t s ' performance on e x p l i c i t and i m p l i c i t memory t e s t s focuses on the processes u n d e r l y i n g these forms of memory (e.g., Graf & Mandler, 1984). S p e c i f i c a l l y , i t was proposed t h a t amnesia spares i m p l i c i t memory performance because i t depends p r i m a r i l y on o v e r l e a r n e d , automatic p r o c e s s e s w h i l e e x p l i c i t memory depends p r i m a r i l y on s u b j e c t -i n i t i a t e d c o n t r o l l e d p r o c e s s e s . Furthermore, t h i s view holds t h a t e x p l i c i t memory i s impaired i n amnesic p a t i e n t s because the d i s e a s e d i m i n i s h e s one's a b i l i t y t o engage i n and/or guide the type of p r o c e s s i n g t h a t mediates e x p l i c i t memory performance. By the view t h a t automatic p r o c e s s i n g i s not a f f e c t e d by s u b j e c t - i n i t i a t e d study t r i a l a c t i v i t i e s , a l e v e l s of p r o c e s s i n g or s i m i l a r m a n i p u l a t i o n r e q u i r i n g s u b j e c t -c o n t r o l l e d study t r i a l a c t i v i t i e s should a f f e c t i m p l i c i t memory t e s t performance i n amnesic p a t i e n t s and c o n t r o l s u b j e c t s . In c o n t r a s t , by the view t h a t e x p l i c i t memory performance depends on c o n t r o l l e d processes, which are impaired i n amnesic p a t i e n t s , a l e v e l s of p r o c e s s i n g manipulation should d i f f e r e n t i a l l y a f f e c t amnesics' and c o n t r o l s ' performance: C o n t r o l s u b j e c t s should have s u p e r i o r performance w i t h m a t e r i a l s processed more s e m a n t i c a l l y , whereas amnesic p a t i e n t s should show no or a reduced l e v e l s of pro c e s s i n g e f f e c t . These e x p e c t a t i o n s were examined i n a study by Graf, S q u i r e , and Mandler (1984, Expt. 3). They manipulated l e v e l of p r o c e s s i n g by having amnesic p a t i e n t s and c o n t r o l s u b j e c t s study words e i t h e r s e m a n t i c a l l y or non-semantically. Semantic p r o c e s s i n g was induced by a s k i n g s u b j e c t s t o r a t e words f o r l i k e a b i l i t y ( i . e . , how much do you l i k e / d i s l i k e what t h i s word means); non-semantic p r o c e s s i n g was induced by a s k i n g them t o count the vowels i n each word. I m p l i c i t memory was assessed w i t h a word completion t e s t , w h i l e e x p l i c i t memory was examined w i t h f r e e - r e c a l l and r e c o g n i t i o n t e s t s . The study showed two important r e s u l t s . F i r s t , i m p l i c i t memory performance was the same ac r o s s semantic/nonsemantic study t a s k s , and second, amnesics performed as w e l l as c o n t r o l s . And as expected, e x p l i c i t memory performance — f r e e r e c a l l and r e c o g n i t i o n — was hi g h e r i n the semantic study c o n d i t i o n s f o r the c o n t r o l s u b j e c t s , but amnesic p a t i e n t s ' performance was s i m i l a r l y impaired i n the semantic and nonsemantic study c o n d i t i o n s . F a m i l i a r items versus new a s s o c i a t i o n s . I t i s p o s s i b l e t h a t amnesia spares i m p l i c i t memory t e s t performance because i t depends on the automatic a c t i v a t i o n of p r e - e x i s t i n g word r e p r e s e n t a t i o n s ( c . f . , Graf & Sch a c t e r , 1985). One way t o examine t h i s p o s s i b i l i t y i s t o t e s t i m p l i c i t memory f o r new m a t e r i a l s t h a t have no p r e - e x i s t i n g r e p r e s e n t a t i o n s i n l o n g -term memory. I f amnesic p a t i e n t s ' i m p l i c i t memory i s i n t a c t w i t h these new m a t e r i a l s i t i s u n l i k e l y t h a t i m p l i c i t memory i s mediated by the a c t i v a t i o n of such r e p r e s e n t a t i o n s (Cermak, 1982). To t e s t t h i s h y p o t h e s i s , Graf and Schacter (1985) examined amnesics' i m p l i c i t memory performance f o r p a i r s of u n r e l a t e d words t h a t were newly a c q u i r e d d u r i n g a p r i o r study t r i a l . In t h i s study, amnesic p a t i e n t s , matched c o n t r o l s , and student c o n t r o l s were asked to study u n r e l a t e d word p a i r s , such as BALANCE-CHAIR. L a t e r , e x p l i c i t memory was assessed w i t h a c u e d - r e c a l l t e s t ; the cue c o n s i s t e d o f the f i r s t word from each s t u d y - l i s t p a i r . I m p l i c i t memory was assessed by p r e s e n t i n g s u b j e c t s w i t h a word-stem completion t e s t . The t e s t - i t e m s i n c l u d e d the f i r s t t h r e e l e t t e r s of the ri g h t - h a n d word from each s t u d y - l i s t p a i r (e.g., CHA ). These cues were shown e i t h e r p a i r e d with the same l e f t - h a n d words as at study (e.g. 12 BALANCE-CHA [ f o r same-context i t e m s ] ) , or p a i r e d w i t h a new word (e.g., BELIEF-CHA • [ f o r d i f f e r e n t - c o n t e x t i t e m s ] ) . The m o t i v a t i o n f o r the sa m e / d i f f e r e n t - c o n t e x t t e s t items was t o assess whether i m p l i c i t memory was a f f e c t e d by a s s o c i a t i o n s t h a t were newly ac q u i r e d d u r i n g the study t r i a l . I t was expected t h a t i f a s s o c i a t i o n s were formed between two words, p a i r i n g a stem w i t h the word from the study l i s t should i n c r e a s e p r i m i n g . In the absence of a s s o c i a t i v e i n f o r m a t i o n a c q u i r e d d u r i n g the study t r i a l , i t was expected t h a t performance would be s i m i l a r on same- and d i f f e r e n t - c o n t e x t t e s t items. By the view t h a t priming r e f l e c t s the automatic a c t i v a t i o n of p r e e x i s t i n g r e p r e s e n t a t i o n s (Graf & Schacter, 1985) and t h a t amnesic p a t i e n t s cannot l e a r n new a s s o c i a t i o n s , two r e s u l t s were expected. F i r s t , amnesics' i m p l i c i t memory performance was not expected t o be a f f e c t e d by the same- vs. d i f f e r e n t -c o n t e x t i n which the word fragments were presented f o r t e s t i n g . The f i n d i n g t h a t t h e i r performance i s a f f e c t e d by the t e s t c o n t e x t m a n i p u l a t i o n would i n d i c a t e t h a t they have some memory f o r a s s o c i a t i o n s t h a t were newly a c q u i r e d d u r i n g the study t r i a l . Second, amnesics' performance was a l s o expected t o be s i g n i f i c a n t l y lower than c o n t r o l s u b j e c t s ' performance on a l l t e s t s because of t h e i r i n a b i l i t y t o form new a s s o c i a t i o n s . Contrary t o the these e x p e c t a t i o n s the r e s u l t s showed t h a t a l l groups, i n c l u d i n g amnesics, performed b e t t e r w i t h same-than d i f f e r e n t - c o n t e x t t e s t items. In a d d i t i o n , i m p l i c i t memory performance was s i m i l a r a c r o s s a l l s u b j e c t groups. These f i n d i n g s i l l u s t r a t e t h a t a t l e a s t some aspects o f i m p l i c i t memory f o r new a s s o c i a t i o n s are i n t a c t i n amnesic p a t i e n t s , thereby suggesting t h a t the s e l e c t i v e s p a r i n g of i m p l i c i t memory i s not c o n f i n e d t o f a m i l i a r m a t e r i a l s , but extends t o e n t i r e l y new m a t e r i a l s encountered i n a s i n g l e study t r i a l . One may a l s o hypothesize from t h i s t h a t new l e a r n i n g may be governed by automatic as w e l l as c o n t r o l l e d processes. The reasoning here i s t h a t s t u d i e s have g e n e r a l l y found i m p l i c i t memory t e s t performance t o be u n a f f e c t e d by c o n t r o l l e d processes (e.g., Graf & Mandler, 1984) and, t h e r e f o r e , i f there i s i m p l i c i t memory f o r new m a t e r i a l s , t h i s new l e a r n i n g has occurr e d a u t o m a t i c a l l y . F i n a l l y , i t i s important t o note t h a t e x p l i c i t memory performance was s e v e r e l y impaired f o r amnesic p a t i e n t s i n a l l c o n d i t i o n s which i s c o n s i s t e n t with the l i t e r a t u r e on amnesic p a t i e n t s ' performance on e x p l i c i t memory t e s t s . R e l a t e d s t u d i e s have a l s o found i n t a c t i m p l i c i t memory with amnesics f o r new i n f o r m a t i o n about people (Schacter, Harbluk, & McLachlan, 1984), s t o r i e s ( L u r i a , 1976), computer programming ( G l i s k y , Schacter, & T u l v i n g , 1986), and new a s s o c i a t i o n s (Moscovitch, Winocur, & Mc l a c h l a n , 1986). M o d a l i t y of study and t e s t l i s t p r e s e n t a t i o n . A d d i t i o n a l i n s i g h t i n t o whether a l l aspects of i m p l i c i t memory are normal i n amnesic p a t i e n t s has come from experiments t h a t have examined performance when m a t e r i a l s were s t u d i e d and t e s t e d w i t h i n the same modality (e.g., a u d i t o r y a t study and t e s t ) , versus d i f f e r e n t m o d a l i t i e s (e.g., a u d i t o r y a t study and v i s u a l a t t e s t ; e.g., Graf, Shimamura, & S q u i r e , 1985). T y p i c a l l y , i m p l i c i t memory performance i s s u p e r i o r under w i t h i n - than across-modality c o n d i t i o n s , whereas e x p l i c i t memory performance i s not i n f l u e n c e d by s i m i l a r m anipulations. To examine i f amnesic p a t i e n t s show a s i m i l a r p a t t e r n of performance between- and wi t h i n - m o d a l i t y c o n d i t i o n s , Graf, Shimamura, and Sq u i r e (1985) t e s t e d i m p l i c i t memory f o r words s t u d i e d e i t h e r v i s u a l l y ( p r i n t e d on cards) or a u d i t o r i a l l y (spoken by experimenter). I m p l i c i t and e x p l i c i t memory t e s t performance were assessed with a v i s u a l word completion t e s t and a f r e e - r e c a l l t e s t , r e s p e c t i v e l y . R e s u l t s i n d i c a t e d t h a t amnesic s u b j e c t s ' i m p l i c i t memory performance was the same as normals; both groups showed higher performance i n w i t h i n - than between-modality c o n d i t i o n s . Amnesic p a t i e n t s ' e x p l i c i t memory t e s t performance, however, was s e v e r e l y impaired compared t o c o n t r o l s and as expected, t h e i r performance was e q u a l l y impaired i n both w i t h i n - and between-modality c o n d i t i o n s . C o n t r o l s u b j e c t s ' performance was the same f o r both s t u d y / t e s t c o n d i t i o n s . The p r e c i s e p a t t e r n o f performance under w i t h i n - and between-modality s t u d y / t e s t c o n d i t i o n s has been i n v e s t i g a t e d more e x t e n s i v e l y i n s t u d i e s with normal a d u l t s u b j e c t s (e.g., K i r s n e r , M i l e c h , & Standen, 1983) and w i l l be d i s c u s s e d i n the next s e c t i o n . The gen e r a l message from t h i s work i s t h a t i m p l i c i t memory i s higher when m a t e r i a l s are s t u d i e d and t e s t e d i n the same modality versus d i f f e r e n t m o d a l i t i e s , whereas e x p l i c i t memory performance i s u n a f f e c t e d by modality c o n d i t i o n s . These f i n d i n g s suggest t h a t i m p l i c i t memory i s mediated a t l e a s t t o some extent by mo d a l i t y s p e c i f i c processes (e.g., Roediger & Blaxton, 1987). F i n d i n g s from s t u d i e s with amnesic p a t i e n t s suggest t h a t such p r o c e s s e s are spared by ac c i d e n t s or d i s e a s e s t h a t impair e x p l i c i t memory t e s t performance. Summary. T h i s c o l l e c t i o n of s t u d i e s i l l u s t r a t e s t h a t amnesic p a t i e n t s who are c h a r a c t e r i s t i c a l l y impaired on t e s t s t h a t r e q u i r e e x p l i c i t memory, perform as w e l l as normal s u b j e c t s on i m p l i c i t memory t e s t s . S p e c i f i c a l l y , amnesics' i m p l i c i t memory performance was normal w i t h f a m i l i a r and u n f a m i l i a r (new a s s o c i a t i o n s ) m a t e r i a l s , w i t h i n - and a c r o s s -modality s t u d y / t e s t m a n ipulations, as w e l l as when they were giv e n d i f f e r e n t study t r i a l a c t i v i t i e s . Other r e s e a r c h e r s have examined amnesics' i m p l i c i t memory performance under v a r i o u s c o n d i t i o n s , such as delay of t e s t i n g (Shimamura & Squire, 1984) and delay o f t e s t i n g with l e v e l of p r o c e s s i n g (Graf, Squire, & Mandler, 1984) and have found i t t o be i n t a c t i n amnesics. This combination of f i n d i n g s has p r o v i d e d s e v e r a l i n s i g h t s . The f i r s t , and most important, i s t h a t i m p l i c i t and e x p l i c i t memory are mediated by d i f f e r e n t u n d e r l y i n g processes. T h i s i s h i g h l i g h t e d by the o v e r a l l f i n d i n g s t h a t amnesic p a t i e n t s ' i m p l i c i t memory performance can be e n t i r e l y normal d e s p i t e t h e i r e x p l i c i t memory performance b e i n g s e v e r e l y impaired. A second i n s i g h t t h a t emerges from these f i n d i n g s concerns the nature of the processes assumed t o mediate i m p l i c i t and e x p l i c i t memory t e s t performance. The f i n d i n g of modality e f f e c t s on i m p l i c i t but not e x p l i c i t memory t e s t performance suggests t h a t they are c o n t r o l l e d by d i f f e r e n t mechanisms — the former guided by m o d a l i t y s p e c i f i c sensory and p e r c e p t u a l processes and the l a t t e r by h i g h e r l e v e l 16 conceptual processes. In combination, these f i n d i n g s g i v e s e v e r a l c l u e s about why i m p l i c i t and e x p l i c i t memory might develop d i f f e r e n t l y a c r o s s the l i f e - s p a n . F i r s t , the f i n d i n g t h a t i m p l i c i t but not e x p l i c i t memory t e s t performance i s spared i n amnesia suggests t h a t the former i s mediated by more b a s i c b r a i n processes than the l a t t e r . I t i s p o s s i b l e t h a t these b a s i c processes develop e a r l i e r i n l i f e and continue t o f u n c t i o n normally i n t o l a t e adulthood. Second, the f i n d i n g of modality e f f e c t s on i m p l i c i t but not e x p l i c i t memory performance suggests t h a t the processes t h a t mediate i m p l i c i t memory are i n i t i a t e d and guided by the sti m u l u s presented a t study and t e s t and they may f u n c t i o n normally even when s u b j e c t s have l o s t the a b i l i t y t o i n i t i a t e and guide complicated p r o c e s s e s . By t h i s view, i m p l i c i t memory may be i n t a c t even when young c h i l d r e n have not y e t a c q u i r e d the a b i l i t y t o c o n t r o l c o g n i t i v e processes. These p o s s i b i l i t i e s are c r i t i c a l t o understanding age e f f e c t s t h a t are t y p i c a l with e x p l i c i t memory t e s t performance as w e l l as the absence of age e f f e c t s with i m p l i c i t memory t e s t performance. They are c o n s i s t e n t with the view t h a t i t i s the c o n t r o l l e d processes t h a t r e s u l t i n performance changes ac r o s s the l i f e - s p a n . The unchanging l e v e l of performance on t e s t s o f i m p l i c i t memory r e f l e c t the o p e r a t i o n of automatic p r o c e s s e s . S t u d i e s with Healthy Young A d u l t s Another important segment of the l i t e r a t u r e on e x p l i c i t and i m p l i c i t memory i n v o l v e s s t u d i e s o f he a l t h y young a d u l t s . T h i s group has been s t u d i e d most e x t e n s i v e l y and has pro v i d e d evidence f o r d i s s o c i a t i o n between i m p l i c i t and e x p l i c i t memory t e s t performance a c r o s s a wide range of c o n d i t i o n s (e.g., Graf, Mandler, & Haden, 1984; Jacoby & D a l l a s , 1981). Performance d i s s o c i a t i o n s have been found as a r e s u l t of semantic versus non-semantic p r o c e s s i n g , f a m i l i a r items versus new a s s o c i a t i o n s , and mod a l i t y of study and t e s t l i s t p r e s e n t a t i o n . The f o l l o w i n g s e c t i o n b r i e f l y reviews the r e l e v a n t r e s e a r c h on each of these f a c t o r s . L e v e l of p r o c e s s i n g a t study. The e f f e c t s of a p r o c e s s i n g m a n i p u l a t i o n on i m p l i c i t and e x p l i c i t memory performance i s i l l u s t r a t e d i n a study by Graf and Mandler (1984, Expt. 3 ) . The c r u c i a l m a n i p u l a t i o n i n t h i s study was semantic and non-semantic p r o c e s s i n g . The semantic c o n d i t i o n r e q u i r e d s u b j e c t s t o r a t e words on a 5-point s c a l e ; the end p o i n t s of the s c a l e were l a b e l l e d LIKE and DISLIKE, r e s p e c t i v e l y . To ensure t h a t s u b j e c t s c o n s i d e r e d the meanings of the words i n t h i s c o n d i t i o n , they were asked t o r a t e how much they l i k e d each of the words u s i n g the LIKE/DISLIKE s c a l e . For the non-semantic c o n d i t i o n , s u b j e c t s focused on the i n t e r n a l f e a t u r e s of the words. T h i s was done by a s k i n g s u b j e c t s t o count and w r i t e down the number of 'T' j u n c t i o n s ( i n t e r s e c t i n g l i n e s ) and the number of completely e n c l o s e d spaces i n each word, thus d i r e c t i n g them t o c o n s i d e r o n l y p e r c e p t u a l f e a t u r e s of the words, not t h e i r meanings. The d i f f e r e n t l e v e l s of p r o c e s s i n g e f f e c t s on i m p l i c i t and e x p l i c i t memory t e s t performance were assessed with word completion and c u e d - r e c a l l t a s k s , r e s p e c t i v e l y . The i m p l i c i t memory t e s t r e s u l t s showed t h a t performance was not a f f e c t e d by the l e v e l s of p r o c e s s i n g m a n i p u l a t i o n . 18 Conversely, e x p l i c i t memory performance was a f f e c t e d by the l e v e l s of p r o c e s s i n g manipulation: R e c a l l performance was hig h e r f o r words s t u d i e d i n the semantic c o n d i t i o n s than f o r those s t u d i e d i n the nonsemantic c o n d i t i o n s . T h i s study, and oth e r s (e.g., Jacoby & D a l l a s , 1981) t h a t have manipulated the type of i n f o r m a t i o n processed a t study, support the h y p o t h e s i s t h a t i m p l i c i t and e x p l i c i t memory are mediated by automatic and c o n t r o l l e d processes, r e s p e c t i v e l y . F a m i l i a r items versus new a s s o c i a t i o n s . I t was i l l u s t r a t e d above t h a t amnesic p a t i e n t s do show i m p l i c i t memory f o r new a s s o c i a t i o n s between p r e v i o u s l y u n r e l a t e d words. T h i s f i n d i n g i s important because i t i l l u s t r a t e s t h a t i m p l i c i t memory t e s t performance may not merely be the r e s u l t of the a c t i v a t i o n o f p r e - e x i s t i n g r e p r e s e n t a t i o n s . While s e v e r a l s t u d i e s have found i m p l i c i t memory f o r newly a c q u i r e d a s s o c i a t i o n s between u n r e l a t e d words i n hea l t h y young a d u l t s (e.g., Graf & Schacter, 1985; Schacter, 1985; C a r r o l l & K i r s n e r , 1982), Graf and Schacter (1985) found i m p l i c i t memory f o r newly formed a s s o c i a t i o n s o n l y when study m a t e r i a l s were processed e l a b o r a t i v e l y . E l a b o r a t i v e p r o c e s s i n g t y p i c a l l y i n v o l v e s engaging the s u b j e c t s i n an a n a l y s i s of the meaning of study m a t e r i a l s . Conversely, n o n - e l a b o r a t i v e p r o c e s s i n g i n v o l v e s l e s s meaningful p r o c e s s i n g of m a t e r i a l s , such as cou n t i n g the number of vowels i n a word. To f u r t h e r i n v e s t i g a t e the i n f l u e n c e s of e l a b o r a t i v e p r o c e s s i n g on i m p l i c i t and e x p l i c i t memory f o r new a s s o c i a t i o n s Schacter and Graf (1986, Expt. 3 & 4) c a r r i e d out another study with new a s s o c i a t i o n s . T h i s study c o n s i s t e d o f a meaningful and an anomalous study c o n d i t i o n . In both c o n d i t i o n s s u b j e c t s were presented with sentences c o n t a i n i n g two t a r g e t words. In the meaningful c o n d i t i o n s u b j e c t s were presented with a meaningful sentence (e.g., "The i n j u r e d OFFICER smelled the FLOWER") and i n the anomalous c o n d i t i o n s u b j e c t s were presented w i t h a nonmeaningful sentence (e.g., "the new ROCK was r e t u r n e d t o the CANDLE"). In both c o n d i t i o n s s u b j e c t s were asked t o r a t e the meaningfulness of the words on a 5-point s c a l e ranging from 'the sentence does not r e l a t e the words m e a n i n g f u l l y ' (1) t o 'the sentence r e l a t e s the words q u i t e m e a n i n g f u l l y ' ( 5 ) . The l e v e l of p r o c e s s i n g m a n i p u l a t i o n (Expt. 4) i n v o l v e d c o n d i t i o n s t h a t r e q u i r e d s u b j e c t s t o e i t h e r r a t e a p a i r of words on pl e a s a n t n e s s - from 'extremely unpleasant' (1) t o 'extremely p l e a s a n t ' (5) - or t o generate a sentence t h a t r e l a t e d the p a i r of words i n a meaningful manner. Another experiment (Expt 1) i n c l u d e d a m a n i p u l a t i o n o f the extent of e l a b o r a t i v e p r o c e s s i n g by having s u b j e c t s generate e i t h e r a s i n g l e word t h a t r e l a t e d the p a i r o f words or to generate a complete sentence (as above). I m p l i c i t and e x p l i c i t memory performance were assessed w i t h word completion and c u e d - r e c a l l t a s k s , r e s p e c t i v e l y . From t h i s study Schacter and Graf (1986, Expt. 3 & 4) found t h a t w h i l e performance on t e s t s of i m p l i c i t and e x p l i c i t memory f o r new a s s o c i a t i o n s both r e q u i r e d e l a b o r a t i o n of meaningful r e l a t i o n s , each was a f f e c t e d d i f f e r e n t l y by d i f f e r e n t types o f a s s o c i a t i v e e l a b o r a t i o n . S p e c i f i c a l l y , when s u b j e c t s generated an a s s o c i a t i o n between two words, i m p l i c i t memory performance was the same whether they generated a s i n g l e 20 word or a complete sentence. Conversely, e x p l i c i t memory t e s t performance was high e r when s u b j e c t s generated an a s s o c i a t i v e r e l a t i o n s with a sentence versus a s i n g l e word. Schacter and Graf (1986) concluded t h a t while e l a b o r a t i o n o f meaningful r e l a t i o n s are v i t a l f o r both i m p l i c i t and e x p l i c i t memory f o r new a s s o c i a t i o n s , only e x p l i c i t memory b e n e f i t s from more ex t e n s i v e e l a b o r a t i o n of meaningful r e l a t i o n s . These d i f f e r e n c e s i n i m p l i c i t and e x p l i c i t memory t e s t performance are important f o r two reasons. F i r s t , they support the hypothesis t h a t these two forms of memory are mediated by d i f f e r e n t u n d e r l y i n g processes. Second, they i l l u s t r a t e the complexity of the ways i n which these two forms of memory operate and they emphasize the need f o r f u r t h e r i n v e s t i g a t i o n . M o d a l i t y of study and t e s t l i s t p r e s e n t a t i o n . Another hypothesis concerning the mediating f a c t o r s of i m p l i c i t and e x p l i c i t memory i s t h a t i m p l i c i t memory, but not e x p l i c i t memory, depends on modality s p e c i f i c processes and, t h e r e f o r e , i s a f f e c t e d by modality manipulations (see Roediger & Blaxton, 1987). T h i s idea has stemmed from s e v e r a l s t u d i e s w i t h normal s u b j e c t s t h a t have found i m p l i c i t memory to be s u p e r i o r when m a t e r i a l s are s t u d i e d and t e s t e d i n one modality (e.g., s t u d i e d and t e s t e d i n v i s u a l modality) than when m a t e r i a l s are s t u d i e d and t e s t e d i n d i f f e r e n t m o d a l i t i e s (Schacter & Graf, 1989; K i r s n e r , M i l e c h , & Standen, 1983; Roediger & Bl a x t o n , 1987). To examine the e f f e c t s of modality on i m p l i c i t and e x p l i c i t memory Graf, Shimamura, and S q u i r e (1985) presented h e a l t h y young a d u l t s with spoken and w r i t t e n words. To ensure t h a t s u b j e c t s analyzed the semantic f e a t u r e s of the study l i s t words, they were asked t o r a t e the words on a 5-point s c a l e — from ' l i k e extremely' (1) t o ' d i s l i k e extremely' ( 5 ) . A f t e r s t u d y i n g the items, i m p l i c i t memory t e s t performance was assessed with a word completion t e s t and e x p l i c i t memory with a f r e e r e c a l l t e s t . The word completion t e s t was always presented v i s u a l l y ; t h e r e f o r e , items s t u d i e d i n the v i s u a l m odality were i n the w i t h i n - m o d a l i t y c o n d i t i o n , and items t h a t were s t u d i e d i n the a u d i t o r y modality were i n the between-modality c o n d i t i o n . Graf, Shimamura, and Squ i r e (1985) found t h a t i m p l i c i t memory t e s t performance was s u p e r i o r i n the w i t h i n - m o d a l i t y c o n d i t i o n than i n the between-modality c o n d i t i o n . C o n v e r s e l y , e x p l i c i t memory t e s t performance was s i m i l a r a c r o s s these c o n d i t i o n s . Summary. These s t u d i e s i l l u s t r a t e t h a t i m p l i c i t and e x p l i c i t memory performance can be d i s s o c i a t e d e x p e r i m e n t a l l y by l e v e l s of p r o c e s s i n g , f a m i l i a r i t y of m a t e r i a l s , and modality manipulations i n h e a l t h y young a d u l t s . Other r e s e a r c h has examined the e f f e c t s o f a v a r i e t y of other manipulations on i m p l i c i t and e x p l i c i t memory performance i n h e a l t h y young a d u l t s under v a r i o u s c o n d i t i o n s , such as delay of t e s t i n g (e.g., Schacter & Graf, 1986; f o r review see Schacter, 1987) and have a l s o found these two forms of memory t o be a f f e c t e d d i f f e r e n t l y . In combination, these f i n d i n g s complement r e s u l t s from s t u d i e s w i t h amnesic p a t i e n t s and they s t r e n g t h e n the c l a i m t h a t i m p l i c i t and e x p l i c i t memory are mediated by d i f f e r e n t u n d e r l y i n g p r o c e s s e s . Developmental S t u d i e s w i t h Young C h i l d r e n or Older A d u l t s A t h i r d domain o f r e s e a r c h r e l e v a n t t o my t h e s i s i s work on the development of i m p l i c i t and e x p l i c i t memory acr o s s the l i f e - s p a n . Developmental s t u d i e s t y p i c a l l y examine how i m p l i c i t and e x p l i c i t memory t e s t performance i s a f f e c t e d by d i f f e r e n t f a c t o r s a t d i f f e r e n t p o i n t s i n the l i f e - s p a n . Such s t u d i e s are important because they can l e a d t o a b e t t e r understanding o f the processes t h a t mediate i m p l i c i t and e x p l i c i t memory t e s t performance. In g e n e r a l , developmental s t u d i e s have found t h a t w h ile e x p l i c i t memory performance i s i n c r e a s i n g e a r l y i n the l i f e - s p a n (e.g., B j o r k l u n d & B j o r k l u n d , 1985) and d e c r e a s i n g l a t e i n the l i f e - s p a n (e.g. Salthouse, 1982), i m p l i c i t memory performance remains r e l a t i v e l y constant throughout the e n t i r e l i f e - s p a n (e.g., Graf, 1990; Greenbaum & Graf, 1989; L i g h t & Singh, 1987). A study by P a r k i n and S t r e e t e (1988) h i g h l i g h t s the d i f f e r e n c e s i n t h i s e a r l y development of i m p l i c i t and e x p l i c i t memory i n c h i l d r e n . They presented 3-, 5-, 7-year o l d s and a d u l t s with fragmented drawings (drawings w i t h m i s s i n g l i n e segments) of v a r i o u s items and asked them t o i d e n t i f y each item. Subjects were f i r s t p resented the most fragmented drawing and then i n c r e a s i n g l y complete drawings. The p r e s e n t a t i o n of items was con t i n u e d e i t h e r u n t i l the s u b j e c t c o r r e c t l y i d e n t i f i e d the drawing o r the f i n a l (complete v e r s i o n ) drawing was shown. L a t e r , s u b j e c t s were presented with another s e t of fragmented drawings t h a t i n c l u d e d both the o r i g i n a l items as w e l l as f i f t e e n d i s t r a c t o r s . I m p l i c i t memory t e s t performance was indexed by the d i f f e r e n c e between the l e v e l s at which the drawing was i d e n t i f i e d on the f i r s t and second p r e s e n t a t i o n s ( s a v i n g s ) . E x p l i c i t memory performance was assessed w i t h a r e c o g n i t i o n t e s t . Here s u b j e c t s were shown the complete drawings of t a r g e t and d i s t r a c t o r items and asked t o s e l e c t those items they had p r e v i o u s l y seen i n the study l i s t . P a r k i n and S t r e e t e (1988) found no s i g n i f i c a n t d i f f e r e n c e s i n i m p l i c i t memory t e s t performance across the f o u r age groups; 3-, 5-, 7- year o l d s and a d u l t s performed e q u a l l y w e l l . In c o n t r a s t , and c o n s i s t e n t w i t h the l i t e r a t u r e , e x p l i c i t memory performance i n c r e a s e d a c r o s s these age-groups; the a d u l t s performed s i g n i f i c a n t l y b e t t e r than 7-year o l d s , 7-year o l d s performed b e t t e r than 5-year o l d s , and 5-year o l d s performed b e t t e r than 3-year o l d s . Another study by Pe r l m u t t e r and Myers (1974) a l s o found e x p l i c i t memory performance t o be s u p e r i o r t o o l d e r c h i l d r e n when t e s t i n g was c a r r i e d out with a r e c o g n i t i o n t a s k . In t h i s study, c o r r e c t r e c o g n i t i o n of p r e v i o u s l y seen items i n c r e a s e d from 81% i n the younger age group (mean = 2 y e a r s , 11 months) t o 92% i n the o l d e r age group (mean = 4 y e a r s ) . T h i s and r e l a t e d f i n d i n g s r a i s e questions about why i m p l i c i t memory performance i s s t a b l e through the e a r l y p a r t of the l i f e - s p a n w h i l e e x p l i c i t memory performance changes. Does development a f f e c t the processes t h a t mediate e x p l i c i t memory but not those processes t h a t u n d e r l i e i m p l i c i t memory? Previou s r e s e a r c h w i t h amnesic p a t i e n t s and w i t h h e a l t h y young a d u l t s r e v e a l s t h a t the o p e r a t i o n s i n v o l v e d i n these two forms of memory are h i g h l y complex, and i t i s hoped t h a t more ex t e n s i v e r e s e a r c h on the e a r l y development o f i m p l i c i t and e x p l i c i t memory t e s t s w i l l i l l u m i n a t e these p r o c e s s e s . 24 L e v e l of p r o c e s s i n g a t study. One hyp o t h e s i s i s t h a t i m p l i c i t memory i s f u l l y developed e a r l y i n l i f e because i t i s mediated by processes t h a t are automatic, whereas e x p l i c i t memory develops l a t e r because i t i s mediated by processes t h a t are s u b j e c t - c o n t r o l l e d or i n i t i a t e d and t h i s c o n t r o l i s ac q u i r e d l a t e r i n the course of development (e.g., K a i l , 1979). I f t h i s i s t r u e , one would expect two c r i t i c a l f i n d i n g s . F i r s t , i f i m p l i c i t memory performance i s mediated by automatic pr o c e s s e s , a l e v e l of p r o c e s s i n g m a n i p u l a t i o n should not a f f e c t performance of any age-groups. In c o n t r a s t , by the view t h a t e x p l i c i t memory performance i s mediated by c o n t r o l l e d processes which develop with i n c r e a s i n g age, a l e v e l s of p r o c e s s i n g m a n i p u l a t i o n should r e v e a l a g e - r e l a t e d performance d i f f e r e n c e s . T h i s view a l s o p r e d i c t s t h a t younger s u b j e c t s , whose e x p l i c i t memory i s not y e t f u l l y i n t a c t , w i l l b e n e f i t more from the l e v e l s o f p r o c e s s i n g m a n i p u l a t i o n than o l d e r c h i l d r e n . The reason i n g here i s t h a t i f young c h i l d r e n l a c k the a b i l i t y t o process m a t e r i a l s more e x t e n s i v e l y , then a t a s k t h a t induces and guides t h i s type of p r o c e s s i n g should b r i n g t h e i r performance up t o a l e v e l comparable t o t h a t of o l d e r s u b j e c t s who are capable of i n i t i a t i n g t h i s type of p r o c e s s i n g on t h e i r own. Nait o ( i n press) i n v e s t i g a t e d some of these i s s u e s i n a study i n v o l v i n g c h i l d r e n i n grade one, t h r e e , s i x , and i n c o l l e g e s t u d e n t s . In two d i f f e r e n t experiments, s u b j e c t s were presented w i t h a 32 item w o r d - l i s t , 16 of which were presented i n a semantic study c o n d i t i o n and 16 i n a non-semantic study c o n d i t i o n . The semantic study c o n d i t i o n r e q u i r e d s u b j e c t s t o i d e n t i f y the semantic category t o which each item belonged. The non-semantic study c o n d i t i o n r e q u i r e d s u b j e c t s t o s t a t e whether or not a p a r t i c u l a r l e t t e r was prese n t or absent i n the word. The f i r s t experiment assessed i m p l i c i t memory wit h a word-fragment completion t e s t , and the second assessed e x p l i c i t memory wit h a f r e e r e c a l l t e s t . As expected, t h e r e was no d i f f e r e n c e i n i m p l i c i t memory t e s t performance across the f o u r age-groups and performance was s i m i l a r a c r o s s the semantic and non-semantic study t a s k c o n d i t i o n s . Conversely, performance on e x p l i c i t memory t e s t s i n c r e a s e d a c r o s s the age groups: C o l l e g e students performed s i g n i f i c a n t l y h i g h e r than f i r s t , t h i r d , and s i x t h g r a d e r s ; and t h i r d and s i x t h graders (who performed the same) performed s i g n i f i c a n t l y h i g h e r than f i r s t g r a d e r s . In a d d i t i o n , a l l age-groups' performance was s u p e r i o r f o r m a t e r i a l s i n the semantic versus the non-semantic study c o n d i t i o n s . However, i n c r e a s e d performance a t t r i b u t e d t o the study c o n d i t i o n was not s u f f i c i e n t t o b r i n g the younger s u b j e c t s ' performance up to the l e v e l of the o l d e r s u b j e c t s ' . The l a t t e r f i n d i n g has two i n t e r p r e t a t i o n s . F i r s t , the e l a b o r a t i v e study c o n d i t i o n may have enabled even the youngest s u b j e c t s t o process m a t e r i a l s t o a g r e a t e r extent than they do on t h e i r own, but t h e i r p r o c e s s i n g was s t i l l not as e x t e n s i v e as t h a t o f o l d e r s u b j e c t s . A second p o s s i b i l i t y i s t h a t e l a b o r a t i v e p r o c e s s i n g i s o n l y one of the f a c t o r s t h a t c o n t r i b u t e s t o the a g e - r e l a t e d d i f f e r e n c e s t y p i c a l l y e x h i b i t e d i n e x p l i c i t memory t e s t performance. O v e r a l l , the r e s u l t s from H a i t o ' s study support the view t h a t i m p l i c i t memory remains constant a c r o s s the l i f e - s p a n and t h a t i t i s u n a f f e c t e d by a l e v e l s of p r o c e s s i n g manipulation, whereas e x p l i c i t memory t e s t performance v a r i e s a c r o s s age-groups t h a t d i f f e r i n t h e i r a b i l i t y t o i n i t i a t e and guide p r o c e s s i n g o f to-be-remembered items. Summary. Previo u s developmental work has pro v i d e d four major f i n d i n g s . F i r s t , i m p l i c i t memory performance remains constant from the p r e s c h o o l age to young adulthood ( i . e . , performance does not i n c r e a s e or decrease across these ages). Second, i m p l i c i t memory performance i s not a f f e c t e d by l e v e l s of p r o c e s s i n g m a n i p u l a t i o n s d u r i n g the same span of l i f e . T h i r d , e x p l i c i t memory performance i n c r e a s e s d u r i n g t h i s e a r l y p a r t of l i f e , and t h i s i n c r e a s e i s most notable between 2- and 4-years of age. Fourth, l e v e l s o f p r o c e s s i n g manipulations tend t o i n c r e a s e e x p l i c i t memory performance f o r both young c h i l d r e n and c o l l e g e - a g e d a d u l t s . The important and f a m i l i a r i m p l i c a t i o n of these f i n d i n g s i s t h a t i m p l i c i t and e x p l i c i t memory are mediated by automatic and c o n t r o l l e d p r o c e s s e s , r e s p e c t i v e l y . These processes are f u l l y f u n c t i o n a l a t d i f f e r e n t p o i n t s i n the l i f e - s p a n , and thus they r e s u l t i n d i f f e r e n t developmental p a t t e r n s of i m p l i c i t and e x p l i c i t memory. General Summary F i v e major f i n d i n g s are i l l u s t r a t e d by s t u d i e s of amnesic p a t i e n t s , h e a l t h y young a d u l t s , and young c h i l d r e n and o l d e r a d u l t s . F i r s t , i m p l i c i t memory performance i s high e r i n wi t h i n - m o d a l i t y c o n d i t i o n s than a c r o s s - m o d a l i t y c o n d i t i o n s f o r both amnesic p a t i e n t s and he a l t h y young a d u l t s . Second, h e a l t h y young a d u l t s ' e x p l i c i t memory performance i s the same whether m a t e r i a l s are s t u d i e d and t e s t e d i n the same or i n d i f f e r e n t m o d a l i t i e s . T h i r d , i m p l i c i t memory f o r newly formed a s s o c i a t i o n s i s present i n both amnesic p a t i e n t s and he a l t h y young a d u l t s . Fourth, across d i f f e r e n t ages, w i t h h e a l t h y young a d u l t s and with amnesic p a t i e n t s , i m p l i c i t memory i s not a f f e c t e d by l e v e l s of p r o c e s s i n g m a n i p u l a t i o n s . F i f t h , e x p l i c i t memory performance i s high e r when m a t e r i a l s are processed more s e m a n t i c a l l y f o r both h e a l t h y young a d u l t s and acro s s d i f f e r e n t age-groups, whereas the same manipulation has no e f f e c t on i m p l i c i t memory t e s t performance. The i m p l i c a t i o n s of these f i n d i n g s a r e , f i r s t , i m p l i c i t and e x p l i c i t memory are mediated by d i f f e r e n t u n d e r l y i n g p r o c e s s e s . Second, the processes mediating i m p l i c i t memory are, t o some exten t , modality s p e c i f i c , whereas those mediating e x p l i c i t focus on semantic/conceptual p r o p e r t i e s o f to-be-remembered m a t e r i a l s . T h i r d , s i n c e t h e r e i s i m p l i c i t memory f o r new m a t e r i a l s , i t i s p o s s i b l e t h a t e i t h e r i m p l i c i t memory i s mediated by c o n t r o l l e d processes or t h a t some new l e a r n i n g i s automatic. Fourth, the processes u n d e r l y i n g i m p l i c i t memory are automatic and are u n a f f e c t e d by e f f o r t s t o c o n t r o l the way i n which m a t e r i a l s are processed. F i f t h , e x p l i c i t memory i s mediated by more c o n t r o l l e d or s e l f - i n i t i a t e d p r o c e s s e s . What f o l l o w s i s a review of t h e o r i e s t h a t attempt t o pr o v i d e e x p l a n a t i o n s f o r these r e s u l t s . Three t h e o r e t i c a l p e r s p e c t i v e s a re reviewed: a c t i v a t i o n , p r o c e s s i n g , and systems views. T h e o r e t i c a l E x p l a n a t i o n s 28 The f o l l o w i n g t h e o r e t i c a l review i s d i v i d e d i n t o t h r e e s e c t i o n s . Each s e c t i o n p r e s e n t s a b r i e f o u t l i n e o f a theory which i s then f o l l o w e d by an account of how w e l l t h a t theory accommodates the f i n d i n g s from s t u d i e s reviewed above. Throughtout t h i s s e c t i o n , two terms — automatic and c o n t r o l l e d p r o c e s s i n g — are used r e p e a t e d l y , and thus, they w i l l be d e f i n e d f i r s t . In a r e c e n t review, Logan (1985) l i s t e d the d i f f e r e n t ways i n which some r e s e a r c h e r s have used the term automatic (Hasher & Zacks, 1979; J o n i d e s , 1981; Logan, 1978, 1979; Posner & Snyder, 1975; Schneider & S h i f f r i n , 1977; S h i f f r i n & Schneider, 1977). Automatic processes are those t h a t "can be performed q u i c k l y , e f f o r t l e s s l y , and r e l a t i v e l y autonomously". Other t h e o r i s t s have emphasized t h a t automatic processes are d i f f i c u l t or i m p o s s i b l e t o c o n t r o l (e.g., J o n i d e s , 1981; Posner & Snyder, 1975). Automatic processes are o f t e n c o n t r a s t e d with c o n t r o l l e d processes and t h e r e i s a tendency t o view automatic and c o n t r o l l e d as a dichotomy (see Logan, 1985). The a l t e r n a t i v e i s t o view them as end-points on a continuum (Logan ,1985) . Throughout my t h e s i s , I use the terms automatic and c o n t r o l l e d t o r e f e r t o processes a t d i f f e r e n t p o i n t s along a continuum. Automatic processes are viewed as being i n i t i a t e d and guided e x t e r n a l l y — by the environment, w h i l e c o n t r o l l e d processes are viewed as being c o n t r o l l e d i n t e r n a l l y — by the i n d i v i d u a l (see C r a i k , 1983). A c t i v a t i o n Views. The b a s i c premise of a c t i v a t i o n theory i s t h a t i m p l i c i t memory a r i s e s from the a c t i v a t i o n of p r e -e x i s t i n g r e p r e s e n t a t i o n s (e.g., Graf & Mandler, 1984; Mandler, 1980). Proponents of t h i s view c l a i m t h a t the d i s s o c i a t i o n of i m p l i c i t and e x p l i c i t memory a r i s e s from the u t i l i z a t i o n of d i f f e r e n t kinds of i n f o r m a t i o n from the same u n d e r l y i n g r e p r e s e n t a t i o n (Graf & Mandler, 1984). Graf and Mandler (1984) argue t h a t when a f a m i l i a r word i s presented f o r study, i t a u t o m a t i c a l l y i t s long-term memory r e p r e s e n t a t i o n . T h i s a c t i v a t i o n causes a s t r e n g t h e n i n g or i n t e g r a t i o n of the r e p r e s e n t a t i o n w i t h the a c t i v a t i n g s t i m u l u s t o form a u n i f i e d whole. In t u r n , t h i s i n t e g r a t i v e p r o c e s s i n g i n c r e a s e s the l i k e l i h o o d of r e - a c t i v a t i o n , or r e d i n t e g r a t i o n , of the r e p r e s e n t a t i o n when onl y p a r t s o f the word are presented on a t e s t (Graf & Mandler, 1984). Furthermore, c o n t r o l l e d processes are not used i n the process of i n t e g r a t i o n or r e d i n t e g r a t i o n and, as a r e s u l t , should have no i n f l u e n c e on i m p l i c i t memory performance. T h i s e x p e c t a t i o n i s c o n s i s t e n t w i t h the general f i n d i n g t h a t i m p l i c i t memory performance i s u n a f f e c t e d by a cons c i o u s e f f o r t t o process m a t e r i a l s e l a b o r a t i v e l y (to a more meaningful l e v e l ) . On t e s t s of e x p l i c i t memory, Graf and Mandler (1984) argue t h a t s u c c e s s f u l performance i s e x h i b i t e d o n l y when the s u b j e c t i s a b l e t o access ( d e l i b e r a t e l y r e c a l l ) the t a r g e t word through one of the paths t o the word. They suggest t h a t such access paths are made more a c c e s s i b l e when one has p e r c e i v e d r e l a t i o n s among a s e t of words. More imp o r t a n t l y , the esta b l i s h m e n t of these r e l a t i o n s t h a t i n c r e a s e the a c c e s s i b i l i t y of a path are achieved through e l a b o r a t i v e p r o c e s s i n g of the words. T h e r e f o r e , when t a r g e t items are e l a b o r a t i v e l y processed, paths l e a d i n g t o t h a t word's r e p r e s e n t a t i o n are made more a c c e s s i b l e . T h i s i s c o n s i s t e n t with the g e n e r a l f i n d i n g t h a t e l a b o r a t i v e p r o c e s s i n g i n c r e a s e s e x p l i c i t memory t e s t performance. By t h i s view there are f o u r b a s i c e x p e c t a t i o n s with i m p l i c i t and e x p l i c i t memory t e s t performance. F i r s t , i m p l i c i t memory performance should not be a f f e c t e d by changes i n the p r o c e s s i n g of study m a t e r i a l s because i t s mediating p r o c e s s e s , a c t i v a t i o n and i n t e g r a t i o n , operate a u t o m a t i c a l l y . Second, i m p l i c i t memory performance should be s t a b l e across the l i f e -span because the processes are automatic and, t h e r e f o r e , should be f u l l y i n t a c t e a r l y i n l i f e . T h i s i s based on the premise t h a t automatic processes are b a s i c and b a s i c processes are f u l l y f u n c t i o n a l long b e f o r e c o n t r o l l e d and more complex p r o c e s s e s . T h i r d , e x p l i c i t memory should be a f f e c t e d by changes i n p r o c e s s i n g because semantic p r o c e s s i n g of m a t e r i a l s d i r e c t l y a f f e c t s a v a i l a b l e paths t o the t a r g e t word. Fourth, e x p l i c i t memory t e s t performance should be f u l l y i n t a c t l a t e r i n l i f e than i s i m p l i c i t memory performance and i n c r e a s e through most of the l i f e - s p a n because i t s mediating processes are c o n t r o l l e d . T h i s i s based on the argument t h a t development i n c r e a s e s the resources t h a t are r e q u i r e d f o r e x p l i c i t memory performance (see Graf, 1990). In summary, an a c t i v a t i o n view makes p r e d i c t i o n s t h a t are supported by the major f i n d i n g s from s t u d i e s with amnesic p a t i e n t s , h e a l t h y young a d u l t s , and young c h i l d r e n and i t pr o v i d e s a u s e f u l t o o l f o r r e s e a r c h with young c h i l d r e n . P r o c e s s i n g views. Proponents of the p r o c e s s i n g view a t t r i b u t e the d i f f e r e n c e s between i m p l i c i t and e x p l i c i t memory t o the d i f f e r e n t p r o c e s s i n g demands a t study and a t t e s t i n g (Schacter, 1987). The b a s i s of t h i s view i s somewhat r e l a t e d t o t r a n s f e r a p p r o p r i a t e p r o c e s s i n g (e.g., K o l e r s & Roediger, 1984; M o r r i s , Bransford, & Franks, 1977). T h i s p e r s p e c t i v e holds t h a t performance on memory t e s t s depends on the s i m i l a r i t y of the processes r e q u i r e d a t study and a t t e s t . In other words, what i s important t o performance are the procedures and s k i l l s one b r i n g s t o a memory ta s k ( K o l e r s & Roediger, 1984). Roediger and Bla x t o n (1987) h o l d a s i m i l a r view of p r o c e s s i n g which i s d i r e c t e d a t the d i s s o c i a t i o n of i m p l i c i t and e x p l i c i t memory. They suggest t h a t t e s t s of i m p l i c i t and e x p l i c i t memory a c t u a l l y d i s t i n g u i s h t a s k s t h a t r e q u i r e d a t a - and c o n c e p t u a l - d r i v e n p r o c e s s i n g , r e s p e c t i v e l y . For example, i n a word i d e n t i f i c a t i o n task s u b j e c t s i d e n t i f y s t u d i e d words a t a b e t t e r r a t e than non-studied words from only a b r i e f glimpse o f the word (Jacoby, 1983b). Roediger and Blaxton (1987) argue t h a t such p r o c e s s i n g i s d a t a - d r i v e n because i t i s dependent upon the s i m i l a r i t y of the p e r c e p t u a l c h a r a c t e r i s t i c s of the m a t e r i a l a t study and t e s t . Conceptual-d r i v e n p r o c e s s i n g , however, t y p i c a l l y employ s u b j e c t - i n i t i a t e d a c t i v i t i e s such as semantic e l a b o r a t i o n and o r g a n i z i n g , which i s s i m i l a r t o the requirements of e x p l i c i t memory t e s t s . Systems views. Systems t h e o r i s t s h o l d the view t h a t d i s s o c i a t i o n s between i m p l i c i t and e x p l i c i t memory a c t u a l l y r e f l e c t d i f f e r e n t u n d e r l y i n g memory systems (Schacter, 1987). T u l v i n g (1985) d e s c r i b e s a memory systems as being an orga n i z e d s t r u c t u r e of elementary o p e r a t i n g components which, i n t u r n , c o n s i s t o f a n e u r a l s u b s t r a t e and i t s b e h a v i o r a l or c o g n i t i v e c o r r e l a t e s . Furthermore, he suggests t h a t such components may be shared by a l l , some, or none of the other memory systems. The systems t h a t T u l v i n g (1985) proposes are the p r o c e d u r a l , semantic and e p i s o d i c memory systems. The pr o c e d u r a l memory system i s i n v o l v e d i n s k i l l l e a r n i n g and r e p e t i t i o n p r i ming. I t i s t o t h i s system t h a t T u l v i n g (1985) a t t r i b u t e s the a b i l i t y t o r e t a i n l e a r n e d connections between s t i m u l i and responses, and he argues t h a t i t mediates i m p l i c i t memory t e s t performance. The semantic memory system i s more long-term and assumed t o r e p r e s e n t f a c t s — knowledge about words, concepts or the world i n g e n e r a l . However, i t l a c k s s p e c i f i c i n f o r m a t i o n r e g a r d i n g the time and pl a c e o f events or where the i n f o r m a t i o n was l e a r n e d . F i n a l l y , T u l v i n g (1985) suggests t h a t the e p i s o d i c memory system c o n t a i n s i n f o r m a t i o n p e r t a i n i n g t o times and p l a c e s . I t i s the e p i s o d i c memory system which i s viewed as the b a s i s f o r e x p l i c i t memory of r e c e n t events (Schacter, 1987). T h i s system i s a l s o s i m i l a r t o the d e c l a r a t i v e memory system which Squire and Cohen (1984) have hypothesized as the b a s i s f o r e x p l i c i t memory. A view more intended to e x p l a i n t h e i m p l i c i t and e x p l i c i t memory d i s s o c i a t i o n i s t h a t put f o r t h by Schacter and Moscovitch (1984). They d i s t i n g u i s h between e a r l y and l a t e d e v eloping memory systems and suggested t h a t the e a r l y d e v e l o p i n g system supports memory a b i l i t i e s seen i n i n f a n t s and young c h i l d r e n . They a l s o suggest t h a t e x p l i c i t memory performance i s mediated by a system t h a t develops l a t e r and i s a f f e c t e d more by traumas. T h i s view e x p l a i n s the changes i n i m p l i c i t and e x p l i c i t memory performance a c r o s s the l i f e - s p a n , but does not e f f e c t i v e l y lend i t s e l f t o e x p l a i n i n g why these two forms of memory performance are d i f f e r e n t . Summary. Each of these above views e x p l a i n some aspect the i m p l i c i t / e x p l i c i t memory performance d i s t i n c t i o n . While the a c t i v a t i o n view seem t o have the g r e a t e s t explanatory power, i t does not f o l l o w from t h i s t h a t i t i s the only view. These views should be co n s i d e r e d t o g e t h e r so t h a t each can be used as a t o o l f o r understanding the d i s s o c i a t i o n between i m p l i c i t and e x p l i c i t memory performance. Chapter 3 STUDY 1: PRE-SCHOOL CHILDREN'S WORD PRODUCTIONS FOR 7 CATEGORIES. The primary g o a l of the f i r s t study was t o c o l l e c t b aserate p r o d u c t i o n data on how f r e q u e n t l y p r e s c h o o l e r s name the d i f f e r e n t items t h a t compose a category, such as CLOTHES. These data were r e q u i r e d f o r use i n the second p a r t of t h i s t h e s i s which examines the i n f l u e n c e of s t u d y i n g category exemplars on p r i m i n g or i m p l i c i t memory t e s t performance. Priming i s i n d i c a t e d by the p r o p o r t i o n of t a r g e t items named i n the experimental c o n d i t i o n ( i . e . , a f t e r study) minus the p r o p o r t i o n of t a r g e t s named i n the baserate c o n d i t i o n ( i . e . , without p r i o r s t u d y ) . Baserate p r o d u c t i o n data were c o l l e c t e d from seven d i f f e r e n t c a t e g o r i e s . The general method was t o i n v i t e s u b j e c t s t o p l a y a game t h a t i n v o l v e d naming items from c a t e g o r i e s . The t a s k was adapted t o the l e v e l of p r e s c h o o l e r s by p r e s e n t i n g i n s t r u c t i o n s i n the form of s h o r t s t o r i e s (see Appendix A ) . Each s t o r y ended with a q u e s t i o n t h a t r e q u i r e d naming items from a c a t e g o r y . Two s l i g h t l y d i f f e r e n t procedures were used. In one, the puppet procedure, s u b j e c t s were i n t r o d u c e d t o one of two plush hand puppets a t the beginning of the s e s s i o n , whereas with the other procedure no puppets were used. The puppets were used t o c r e a t e a p l a y s e s s i o n (the experimenter manipulated the puppets so they appeared t o read the s t o r i e s and ask the q u e s t i o n s ) f o r the c h i l d r e n , as opposed t o a q u e s t i o n i n g s e s s i o n . I t was hoped t h a t the p l a y s e s s i o n would h e l p c h i l d r e n f e e l more comfortable with the experimenter and maintain t h e i r i n t e r e s t i n the study f o r a longer p e r i o d of time. Method M a t e r i a l s Category p r o d u c t i o n norms were c o l l e c t e d f o r seven c a t e g o r i e s l o o s e l y d e f i n e d as TOYS, animals i n a ZOO, t h i n g s used f o r TRAVEL (modes of t r a n s p o r t a t i o n ) , t h i n g s you see i n a RESTAURANT, t h i n g s you see i n a KITCHEN, t h i n g s you see at a PLAYGROUND, and CLOTHES. The s e l e c t i o n o f c a t e g o r i e s was based on t h e i r f a m i l i a r i t y t o 3-year-olds. Seven s t o r i e s , each three to four sentences long, were used t o e l i c i t naming of items from a category (see Appendix A ) . Each s t o r y ended wi t h a qu e s t i o n t h a t i n q u i r e d e i t h e r about something the p r o t a g o n i s t saw when v i s i t i n g a p l a c e (e.g., what animals Kerry saw at the zoo) or about p o s s i b l e s o l u t i o n s t o a problem (e.g., what K e l l y ' s parents c o u l d r i d e i n when going t o v i s i t t h e i r r e l a t i v e s ) . Two p l u s h hand puppets (an a l l i g a t o r and a pig) were used f o r the puppet procedure. The puppets were i n t r o d u c e d t o c r e a t e a play-time s e s s i o n f o r the c h i l d r e n i n order to maintain t h e i r i n t e r e s t f o r a longer p e r i o d o f time. The procedure without the puppets served t o asses the i n f l u e n c e of puppets on c h i l d r e n ' s performance. Subjects N i n e t y - s i x p r e s c h o o l e r s (42 boys and 54 g i r l s ) from daycare c e n t e r s i n Vancouver served as s u b j e c t s . There were 35 three-year o l d s (15 boys and 20 g i r l s ) w i t h a mean age of 3.5 years (range: 3.0 - 3.9), 32 fo u r - y e a r o l d s (13 boys and 19 g i r l s ) w i t h a mean age of 4.48 years (range: 4.0 - 4.9) and 29 f i v e - y e a r o l d s (14 boys and 15 g i r l s ) with a mean age of 5.20 years (range: 5.0 - 5.7). The number of c h i l d r e n t e s t e d i n each group i s presented i n Table 1. Table 1 Number of Subjec t s per Age-group Tested i n Each C o n d i t i o n . 3-years 4-years 5-years T o t a l Puppet 18 19 16 53 No Puppet 17 13 13 43 T o t a l 35 32 29 96 Design and Procedure The procedure c o n s i s t e d o f an i n t r o d u c t i o n and i n s t r u c t i o n p e r i o d f o l l o w e d by seven c o n s e c u t i v e t r i a l s . For the f i r s t p e r i o d c h i l d r e n were i n t r o d u c e d t o the experimenter and i n v i t e d t o p l a y a s t o r y game with her. F i r s t , the experimenter went with the c h i l d r e n t o a q u i e t room or corner away from the r e g u l a r a c t i v i t i e s . A f t e r making f r i e n d l y c o n v e r s a t i o n with the c h i l d r e n the experimenter gave the f o l l o w i n g i n s t r u c t i o n s : "What we are going t o do i s p l a y a s t o r y game. I'm going t o read you a s t o r y and then I am going t o ask you a question t h a t w i l l h e l p you to f i n i s h the s t o r y f o r me. Okay, are you ready? Here i s the f i r s t s t o r y . . . " For each t r i a l , the c h i l d was read a s t o r y and then asked a q u e s t i o n t h a t r e q u i r e d naming items from the category t a r g e t e d by the s t o r y . Each t r i a l focused on a d i f f e r e n t c a t e g o r y and the 7 c a t e g o r i e s were t e s t e d i n a random or d e r . Each t r i a l began with r e a d i n g the s t o r y t h a t was r e l a t e d t o one of the c a t e g o r i e s . The s t o r i e s are presented i n Appendix A. Each s t o r y ended i n a q u e s t i o n t h a t r e q u i r e d c h i l d r e n t o name items from one of the t a r g e t c a t e g o r i e s ( i . e . , "What c o u l d K e l l y ' s p arents r i d e i n t o go v i s i t t h e i r r e l a t i v e s ? " was used t o encourage c h i l d r e n t o name items from the category TRAVEL). C h i l d r e n were encouraged t o name f i v e d i f f e r e n t items f o r each categ o r y ; when they had d i f f i c u l t y naming more items, they were prompted with a rephrased v e r s i o n of the q u e s t i o n . The same rephrased q u e s t i o n s were a l s o presented to the c h i l d r e n i f they p e r s e v e r a t e d on d i f f e r e n t types of the same item (e.g., i n s t e a d of naming d i f f e r e n t items found i n a r e s t a u r a n t they name d i f f e r e n t k i n d s of food, such as hamburgers and hotdogs). T h i s was done to encourage the naming of d i f f e r e n t c a t e g o r y exemplars. The d i f f e r e n t q u e s t i o n s used f o r each categ o r y are a l s o l i s t e d i n Appendix A. F i n a l l y , because an a l l i g a t o r and a p i g puppet were used as a . c o n d i t i o n of the experiment, c h i l d r e n were asked to name animals o t h e r than p i g or a l l i g a t o r f o r the category ZOO. R e s u l t s The c r i t i c a l data are the items named f o r each category by each age-group. Data analyses f o c u s e d on three dependent v a r i a b l e s : the o v e r a l l number of items named f o r each category, the number of d i f f e r e n t items named f o r each category, and the p r o p o r t i o n o f s u b j e c t s t h a t named each item. P r e l i m i n a r y analyses showed no s i g n i f i c a n t d i f f e r e n c e s i n 38 performance between boys and g i r l s or between the puppet and no puppet c o n d i t i o n . Consequently, the data were c o l l a p s e d a c r o s s these v a r i a b l e s f o r a l l subsequent a n a l y s e s . The a l p h a - l e v e l f o r a l l s t a t i s t i c a l t e s t s was s e t a t .05 u n l e s s otherwise i n d i c a t e d . A l l ANOVA t a b l e s are presented i n Appendix B. Word P r o d u c t i o n Frequencies. Appendix C l i s t s the d i f f e r e n t words named f o r each categ o r y by 3-, 4-, and 5-year o l d s . The l i s t a l s o c ontains the number of s u b j e c t s and the p r o p o r t i o n o f s u b j e c t s t h a t named each word i n response t o each c a t e g o r y q u e s t i o n . I t i s the l a t t e r v a l u e t h a t provides the more u s e f u l index of category p r o d u c t i o n t e s t baserate performance. The items are l i s t e d i n two ways, a l p h a b e t i c a l l y and n u m e r i c a l l y (by frequency of p r o d u c t i o n ) . P a r t s of the p r o d u c t i o n data (the 20 most f r e q u e n t l y named words per category) are d i s p l a y e d i n h i s t o g r a p h form i n Appendix D. For each graph the o r d i n a t e represents the p r o p o r t i o n of s u b j e c t s naming each word and the a b s c i s s a l i s t s them by frequency. The most important f i n d i n g t h a t i s underscored by both the l i s t s i n Appendix C and the h i s t o g r a p h s i n Appendix D i s the d i f f e r e n c e i n response h i e r a r c h i e s a c r o s s c a t e g o r i e s . For the c a t e g o r y CLOTHES, f o r example, a s m a l l p o r t i o n of the words were named by a l a r g e p r o p o r t i o n of s u b j e c t s . In c o n t r a s t , f o r c a t e g o r y TOYS, responses are spread more evenly over a l a r g e number of words. The analyses t h a t f o l l o w provide d i f f e r e n t methods f o r d e s c r i b i n g t h i s d i f f e r e n c e i n responding a c r o s s c a t e g o r i e s . Number of Items. Although the i n s t r u c t i o n s r e q u i r e d c h i l d r e n t o name f i v e items from each category, many of the youngest c h i l d r e n found t h i s task d i f f i c u l t . For t h i s reason, the dependent v a r i a b l e f o r the f i r s t a n a l y s i s was the average number of responses produced by each age group f o r each category. T h i s average was c a l c u l a t e d by t a k i n g the t o t a l number of responses f o r a p a r t i c u l a r c ategory and age-group and d i v i d i n g i t by the number of c h i l d r e n t e s t e d . The r e s u l t s , summarized i n Tab l e 2, h i g h l i g h t two p o i n t s . F i r s t , t h e r e are no l a r g e d i f f e r e n c e s i n the average number of items named acro s s the c a t e g o r i e s . T h i s o b s e r v a t i o n was confirmed by a one-way ANOVA wit h category as the independent v a r i a b l e , F(6,14) = .298, MS C = .239. More i m p o r t a n t l y , the t a b l e d means show t h a t the 3-year o l d s named fewer items per category than both the 4- and 5-year o l d s , which d i d not d i f f e r from each o t h e r . T h i s o b s e r v a t i o n was confirmed by a one-way ANOVA t h a t showed a s i g n i f i c a n t main e f f e c t f o r age-group, F(2,18) = 29.706, MS e = .049. Follow-up analyses u s i n g Tukey's HSD t e s t showed t h a t the 3-year o l d s named s i g n i f i c a n t l y fewer items than the 4-year o l d s , p_<.001, and the 5-year-olds, p_<.001, while the 4- and 5-year o l d s d i d not d i f f e r . Number of D i f f e r e n t Items. While the above a n a l y s i s showed t h a t 3-year o l d s named fewer items than the 4- and 5-year o l d s , i t does not i n d i c a t e whether the d i v e r s i t y of items named by 3-year o l d s i s s i m i l a r t o t h a t of 4- and 5-year o l d s . The number of d i f f e r e n t items named f o r a category i s one way to assess the d i v e r s i t y of responses f o r a g i v e n category. A d i f f e r e n t and more p r e c i s e method of a s s e s s i n g category d i v e r s i t y i s d i s c u s s e d l a t e r . The next a n a l y s i s examines category d i v e r s i t y with the number of d i f f e r e n t items Table 2 The Mean Number of Items Named per C h i l d f o r Each Category Subject Age Group 3 years 4 years 5 years Category n* Items + n Items n Items M SD Clo t h e s 30 4 .17 32 4.84 28 4.93 4.64 .41 K i t c h e n 30 4.23 31 4.94 28 4.75 4.64 .37 Zoo 32 4.06 32 4.84 28 4.96 4.62 .49 Playground 31 4.06 32 4.66 28 4.61 4.44 .33 Restaurant 29 3.87 32 4.53 27 4 .70 4.37 .44 T r a v e l 31 3.39 31 4.84 28 4.79 4.34 .82 Toys M 28 3 .89 32 4.66 27 4.32 4.29 .39 3.95 4.76 4.72 SD .28 .14 .22 * Number of c h i l d r e n t h a t were t e s t e d on each category. + Mean number of items named per c h i l d . named f o r each category as the dependent v a r i a b l e . To o b t a i n an index of d i v e r s i t y , I d i v i d e d the number of d i f f e r e n t responses per ca t e g o r y and age-group by the number of s u b j e c t s i n t h a t c o n d i t i o n . The r e s u l t s are summarized i n Table 3. The c e l l means h i g h l i g h t two main f i n d i n g s . F i r s t , t h e r e were only minimal d i f f e r e n c e s a c r o s s age-groups with r e s p e c t t o the number of d i f f e r e n t items named. A one-way ANOVA with age as the independent v a r i a b l e confirmed t h i s o b s e r v a t i o n , F(2,18) = .004, MSe = .436. Second, t h e r e were l a r g e d i f f e r e n c e s a c r o s s c a t e g o r i e s w i t h r e s p e c t t o the number of d i f f e r e n t items named. T h i s was confirmed by a one-way ANOVA which showed a s i g n i f i c a n t main e f f e c t f o r category, F(6,14) = 115.726, MSe = .011. Follow-up a n a l y s e s u s i n g Tukey's HSD t e s t are presented i n Table 4. They p o i n t t o s i g n i f i c a n t d i f f e r e n c e s f o r a l l but the f o l l o w i n g category p a i r s : RESTAURANT/PLAYGROUND, KITCHEN/ZOO, CLOTHES/TRAVEL, and PLAYGROUND/ZOO. Response r a t e c o r r e l a t i o n s across age-groups. Another method of indexing d i f f e r e n c e s i n the naming of items across age-groups i s t o compute a Pearson c o r r e l a t i o n c o e f f i c i e n t on the response r a t e s ( p r o p o r t i o n of s u b j e c t s t h a t named each i t e m ) . The f o l l o w i n g analyses asked, f o r example, how s i m i l a r are response r a t e s of 3-year o l d s t o those of 4-year o l d s ? What we expected was t h a t o l d e r s u b j e c t s s h o u l d name more items than younger s u b j e c t s because they have been exposed t o more category exemplars. I f t h i s i s t r u e , there would be i n c r e a s i n g category d i v e r s i t y w i t h i n c r e a s i n g age-groups. The l a r g e r the d i s c r e p a n c y between two age-groups with r e s p e c t t o response Table 3 The Mean Number of D i f f e r e n t Items Named f o r Each Category Subject Age Group 3 years 4 years 5 years Category n* Items"1" n Items n Items M SD Toys 28 2 .75 32 2.91 27 2 .89 2.85 .09 Restaurant 29 1.79 32 1.84 27 1.81 1.81 .02 Playground 31 1.83 32 1.69 28 1.61 1.71 .11 Zoo 32 1.25 32 1.41 28 1.61 1.42 .18 K i t c h e n 30 1.47 31 1.35 28 1.39 1.40 .06 C l o t h e s 30 1.03 32 .84 28 1.07 .98 .12 T r a v e l 31 .90 31 .97 28 .82 .90 .07 M 1.57 1.57 1.60 SD .63 .69 .66 * Number of c h i l d r e n t h a t were t e s t e d on each category. + Mean number of d i f f e r e n t items named per c h i l d . 43 Table 4 D i f f e r e n c e s between the mean number of d i f f e r e n t responses  produced f o r each category. T r a v e l Toys R e s t r n t P l a y g r d Zoo K i t c h e n Clothes Toys 0.00 R e s t r n t 1.04*** 0.00 Pl a y g r d 1.14*** 0.10 n s 0.00 Zoo 1.43*** 0.39** 0.29 n s 0.00 Ki t c h e n 1.45*** 0.41** 0.31* 0.02 n s 0.00 Clothes 1.87*** 0.83*** 0.73*** 0.42** 0.44** 0.00 T r a v e l 1.95*** * * * 0.91 0.81*** 0.50*** 0.52*** 0.08 n s 0.00 ns= non s i g n i f i c a n t ; * = p<.05.; ** = p< .01; *** = p<.001 r a t e s , the lower s h o u l d be the c o r r e l a t i o n c o e f f i c i e n t of response r a t e s . Note, however, t h a t the c a t e g o r y might not be as d i v e r s e as expected because, i n a d d i t i o n t o i n c r e a s i n g knowledge of d i f f e r e n t category exemplars w i t h age, o l d e r s u b j e c t s are a l s o more l i k e l y t o have more ca t e g o r y knowledge. One p o s s i b l e r e s u l t o f t h i s i s that the o l d e r c h i l d r e n are more l i k e l y t o name t y p i c a l category exemplars and, t h e r e f o r e , produce a l e s s d i v e r s e category which would i n c r e a s e c o r r e l a t i o n c o e f f i c i e n t s . To examine the s e p o s s i b i l i t i e s I rank-ordered the words by response frequency (see L i s t 2 i n Appendix C) of each age-group. I then c o r r e l a t e d the response r a t e s f o r a l l items between the d i f f e r e n t age-groups using a Pearson c o r r e l a t i o n c o e f f i c i e n t . T a b l e 5 p r e s e n t s two c o r r e l a t i o n s c o e f f i c i e n t s f o r each age-group p a i r a c r o s s the seven c a t e g o r i e s . The f i r s t i s based on a l l the items named f o r a ca t e g o r y . The second c o r r e l a t i o n c o e f f i c i e n t (the one i n brac k e t s ) i s based on only the 20 most f r e q u e n t l y named items. T h i s l a t t e r c o e f f i c i e n t p r o v i d e s an index of the d i s p a r i t y of response r a t e s between two age-groups f o r items considered more t y p i c a l of each category as w e l l as reduce i n f l a t e d c o r r e l a t i o n s i n l a r g e c a t e g o r i e s with o u t l y i n g s c o r e s . The t a b l e d c o r r e l a t i o n s h i g h l i g h t two main f i n d i n g s . F i r s t , response r a t e s between 3- and 4-, 3- and 5-, and 4- and 5-year o l d s were s i m i l a r f o r each category: For a giv e n category, 3-year o l d s ' responded j u s t as s i m i l a r l y t o 4- and 5-year ol d s as 4- and 5- year o l d s t o each o t h e r . The second important f i n d i n g t o note i s t h a t the c o r r e l a t i o n s vary Table 5 C o r r e l a t i o n s c o e f f i c i e n t s f o r each category and age-group p a i r  based on the p r o p o r t i o n of s u b j e c t s t h a t named each item. Age Group P a i r s Three Three Four & Four & F i v e & F i v e C l o t h e s .956* ( .959) + .927 ( .913) .954 ( .947) Playground .937 ( .945) .927 ( .946) .917 ( .915) T r a v e l .907 ( .892) .900 ( .882) .954 ( .939) Zoo .886 ( .855) .857 ( .821) .852 ( .827) K i t c h e n .741 ( . 385) .742 ( .451) .697 ( .311) Restaurant .551 ( .743 ) .553 ( .668 ) .903 ( .912) Toy . 320 ( .346) .207 ( .175) .391 ( .423) * C o e f f i c i e n t based on a l l items named f o r t h a t category. + C o e f f i c i e n t based on 20 most common items. c o n s i d e r a b l y a c r o s s c a t e g o r i e s . T h i s r e s u l t o c c u r s because the p r o p o r t i o n of s u b j e c t s naming each item v a r i e d a c r o s s c a t e g o r i e s . Furthermore, i t r e f l e c t s the f a c t t h a t response r a t e s were more s i m i l a r a c r o s s age-groups f o r some c a t e g o r i e s than f o r o t h e r s . For example, response h i e r a r c h i e s were s i m i l a r f o r a l l t h r e e age-groups f o r the c a t e g o r y CLOTHES (see Appendix D), but very d i f f e r e n t f o r the c a t e g o r y TOY. Note t h a t the higher the c o r r e l a t i o n the g r e a t e r agreement between the two age-groups i n terms of which items are r e p r e s e n t a t i v e exemplars of t h a t c a tegory. S i m i l a r l y , those w i t h lower c o r r e l a t i o n s i n d i c a t e l e s s agreement concerning category exemplars. Index of Commonality. Uniform responding t o c a t e g o r i e s p r o v i d e s an index of response commonality a c r o s s age-groups. Commonality i s the complement of d i v e r s i t y of responses. I f most s u b j e c t s name the same words i n response t o a category cue (the commonality of responding i s h i g h ) , the frequency h i s t o g r a m / d i s t r i b u t i o n w i l l have a marked p o s i t i v e skew; i n c o n t r a s t , i f most s u b j e c t s name d i f f e r e n t items f o r a category, response commonality i s low and the d i s t r i b u t i o n w i l l be more spread out. I computed Nelson's (1977) Index of Commonality (IC) which i s the r a t i o of the frequency of the three most popular responses f o r a category t o the t o t a l number o f responses (tokens) named f o r t h a t category. For the denominator, only the f i r s t t h ree responses from each s u b j e c t were used t o compute the IC value i n s t e a d of the t o t a l number of responses because younger s u b j e c t s tended t o produce fewer responses (than the r e q u i r e d f i v e ) than the o l d e r s u b j e c t s . IC va l u e s can range from one to near zero, with the l a r g e r v a l u e s r e f l e c t i n g more common or ster e o t y p e d responding a c r o s s s u b j e c t s . Three IC value s — one f o r each age-group — were c a l c u l a t e d f o r each of the seven c a t e g o r i e s and are presented i n Table 6. The IC means h i g h l i g h t two tr e n d s . F i r s t , t h e r e was an i n c r e a s e i n o v e r a l l commonality between 3-and 4-year o l d s , and a s l i g h t decrease between 4- and 5-year-olds. Secondly, IC r a t i o s v a r i e d c o n s i d e r a b l y across the d i f f e r e n t c a t e g o r i e s . A one-way ANOVA of IC va l u e s w i t h age as the independent v a r i a b l e showed no d i f f e r e n c e s a c r o s s age-groups, £(2,18) = 1.156, MS e = .027. However, a one-way ANOVA of IC values w i t h c a t e g o r i e s as the independent v a r i a b l e showed a s i g n i f i c a n t d i f f e r e n c e a c r o s s c a t e g o r i e s , F(6,14) = 12.755, MS C = .006. Tukey HSD fo l l o w - u p comparisons r e v e a l e d s i g n i f i c a n t category d i f f e r e n c e s i n responding and are presented i n Table 7. Note t h a t the category TOY had a s i g n i f i c a n t l y lower IC value than a l l o ther c a t e g o r i e s ; i t a l s o had the lowest degree of commonality. Type/Token R a t i o s . The complement of category t y p i c a l i t y , as r e f l e c t e d by the IC r a t i o , i s category d i v e r s i t y . The d i f f e r e n c e between t y p i c a l i t y and d i v e r s i t y i s t h a t the f i r s t r e f l e c t the degree t o which the same items are named by d i f f e r e n t i n d i v i d u a l s (the peakedness of the d i s t r i b u t i o n ) , whereas the l a t t e r r e f l e c t s the d i v e r s i t y of items (the spread of the d i s t r i b u t i o n ) . Above, c a t e g o r y d i v e r s i t y was assessed Table 6 Index of commonality values f o r each age-group and f o r each  ca t e g o r y . Subject Age-Group Category 3-Years 4-Years 5-Years M SD C l o t h e s .534* .742 .714 .663 .11 Playground .562 .677 .691 .643 .07 T r a v e l .548 .696 .631 .625 .07 Restaurant .350 .589 .519 .486 .12 Zoo .473 .521 .455 .483 .03 K i t c h e n .352 .430 .402 .395 .04 Toy .175 .258 .210 .214 .04 M .428 .559 .517 SD .14 .17 .17 *IC = frequency of 3 most popular responses f o r a category t o t a l # of responses ( f i r s t 3 only) f o r each category 49 Table 7 Tukey Comparisons: D i f f e r e n c e s i n Index of Commonality R a t i o s  For Each P a i r of C a t e g o r i e s . C l o t h e s P l a y g r d T r a v e l R e s t r n t Zoo Ki t c h e n Toys C l o t h e s .000 P l a y g r d • 020 n s .000 T r a v e l • 038 n s .018 n s .000 R e s t r n t • 177 n s .157 n s .139 n s ' .000 Zoo .180 n s .160 n s .230* .003 n s .000 K i t c h e n .268* .248* .142 n s .091 n s .088 n s .000 Toys .449*** *** .429 .411*** .272** .269* .181*** .000 ns= non s i g n i f i c a n t ; * = p<.05. ; ** = p< .01; *** = p<.001 i n terms of the number of d i f f e r e n t items named f o r a given category. A more s o p h i s t i c a t e d measure of d i v e r s i t y i s a type/token r a t i o (TTR) t h a t c o n s i s t s of the t o t a l number of d i f f e r e n t responses d i v i d e d by the t o t a l number of responses f o r t h a t category (Nelson, 1974). The TTR equals one when a l l responses t o a category occur o n l y once, and i t approaches zero when a l l s u b j e c t s g i v e the same responses. Three TTR v a l u e s were c a l c u l a t e d per c a t e g o r y — one f o r each of the t h r e e age-groups — and are presented i n Table 8. The t a b l e h i g h l i g h t s t h a t TTR values are q u i t e s i m i l a r across age-groups f o r most c a t e g o r i e s . A one-way ANOVA on TTR values w i t h age as the independent v a r i a b l e showed no d i f f e r e n c e between age-groups. By c o n t r a s t , t h e r e was a wide range of TTR v a l u e s among the seven c a t e g o r i e s . A one-way ANOVA confirmed a s i g n i f i c a n t d i f f e r e n c e across c a t e g o r i e s , F(6,14) = 38.388, MS C = .002. Tukey HSD follow-up comparisons were c a r r i e d out on the mean categor y TTR v a l u e s and are presented i n Table 9. Again, the category TOYS stands out as i t s TTR value i s s i g n i f i c a n t l y h i g h e r (more d i v e r s e ) than a l l other c a t e g o r i e s . To assess the r e l a t i o n s h i p between IC and TTR values a Pearson c o r r e l a t i o n c o e f f i c i e n t was c a l c u l a t e d based on the two v a l u e s p a i r e d a c r o s s c a t e g o r i e s and age-groups. The two values were h i g h l y n e g a t i v e l y c o r r e l a t e d (r=-.926) which confirms t h a t TTR and IC v a l u e s index complementary aspects of the response d i s t r i b u t i o n . S p e c i f i c a l l y , IC v a l u e s are l a r g e s t when response d i s t r i b u t i o n s are h i g h l y skewed ( o n l y a few items named, but each w i t h a h i g h frequency), w h i l e TTR values are l a r g e s t when response d i s t r i b u t i o n s are v e r y f l a t (many items Table 8 Type/Token R a t i o s For C a t e g o r i e s and Across Age-groups. Su b j e c t Age-group Category 3-Years 4-Years 5-Years _M SD T r a v e l .267* .200 .172 .213 .05 C l o t h e s .256 .174 .217 .216 .04 K i t c h e n .346 .275 .293 .305 .04 Zoo . 308 .290 . 324 .307 .02 Playground .437 .362 .349 .383 .05 Restaurant .500 .407 .386 .431 .06 Toy .706 .633 .645 .661 .04 M .403 .334 .341 SD .16 .15 .15 *TTR = it of d i f f e r e n t responses f o r one category t o t a l # of responses f o r one category 52 Table 9 Tukey comparisons: Mean d i f f e r e n c e i n type/token r a t i o s f o r  each p a i r of c a t e g o r i e s . Toys R e s t r n t P l a y g r d Zoo K i t c h e n C l o t h e s T r a v e l Toy .000 R e s t r n t .230*** .000 P l a y g r d .278*** .048 n s .000 Zoo .354*** .124 n s •076 n s .000 K i t c h e n .356*** .126* .078 n s .002 n s .000 Cl o t h e s .445*** .215*** .167** .091 n s .089 n s .000 T r a v e l .448*** .218*** .170** .043 n s •092 n s .003 n s .000 ns= non s i g n i f i c a n t ; * = p<.05.; ** = p<. 01; **.* = p<.001 53 being named, but each w i t h a low frequency). T y p i c a l i t y / d i v e r s i t y r a t i o (TDR). The IC and TTR provide u s e f u l d e s c r i p t i o n s of category production norms. But, when these norms are used, experimenters o f t e n want t o s e l e c t items w i t h d i f f e r e n t production frequencies — some t h a t occur r a r e l y and others more f r e q u e n t l y . For t h i s purpose i t i s more u s e f u l t o have an index t h a t provides a more complete d e s c r i p t i o n of a category than e i t h e r the IC or TTR alone. The TDR provides such a d e s c r i p t i o n . One p o s s i b l e way of combining IC and TTR r a t i o s i s t o average the two values.. The problem w i t h t h i s , however, i s t h a t the same average may be achieved e i t h e r when IC i s high and TTR i s low, or v i c e versa. In other words, the value r e s u l t i n g from averaging IC and TTR values i s not uniquely determined. Therefore, a u s e f u l combination of IC and TTR values i s a t y p i c a l i t y / d i v e r s i t y r a t i o (TDR). This r a t i o can be formed two ways: One i s t o d i v i d e TTR values by IC va l u e s , and the other i s to d i v i d e IC values by TTR values. For the present study, I used IC values ( t y p i c a l i t y ) f o r the numerator and TTR values ( d i v e r s i t y ) f o r the denominator. I s e l e c t e d t h i s r a t i o because I wanted the TDRs t o increase as category t y p i c a l i t y increased s i n c e t y p i c a l i t y i s the c r u c i a l f a c t o r i n s e l e c t i n g items f o r a developmental priming study (without a few good category exemplars, few comparisons could be made across age-groups). A comprehensive range of production frequencies f o r a category occurs when TTR and IC are about the same. In t h i s case, the TDR f o r a category w i l l be about one. I f the TDR value i s l e s s than 1 the category i s more d i v e r s e than t y p i c a l , but i f i t i s g r e a t e r than 1, the category i s more t y p i c a l than d i v e r s e . Table 10 i l l u s t r a t e s the d i f f e r e n c e s i n TDR valu e s a c r o s s c a t e g o r i e s , and across the age-groups. A one-way ANOVA on TDRs r e v e a l e d no o v e r a l l age e f f e c t , F(2,18) = 1.105, MS e = 1.195. By c o n t r a s t , there was an o v e r a l l main e f f e c t f o r c a t e g o r i e s , F(6,14) = 9.508, MS e = .340. Follow-up Tukey HSD comparisons were c a r r i e d out on the mean TDRs of the c a t e g o r i e s and are presented i n Table 11. Note t h a t the c a t e g o r i e s CLOTHES and TRAVEL are the only c a t e g o r i e s with s i g n i f i c a n t l y higher TDR va l u e s than any of the oth e r c a t e g o r i e s i n d i c a t i n g t h a t they have a slow, but steady, d r o p - o f f i n response r a t e s . T h i s i s c l e a r l y i l l u s t r a t e d i n the h i s t o g r a p h s of the c a t e g o r i e s presented i n Appendix D. General D i s c u s s i o n The general purpose of t h i s study was t o c o l l e c t data on the frequency with which p r e s c h o o l e r s name items from seven d i f f e r e n t c a t e g o r i e s . R e s u l t s are summarized i n terms of age d i f f e r e n c e s and category d i f f e r e n c e s . Age d i f f e r e n c e s . The onl y s i g n i f i c a n t age d i f f e r e n c e was t h a t 3-year o l d s named fewer items than 4- and 5-year o l d s . T h i s i s an important d i f f e r e n c e t o note with r e s p e c t t o priming s t u d i e s because i f one s u b j e c t group does not name as many items as the other groups, they are a l s o l e s s l i k e l y t o show priming ( i . e . , name as many s t u d i e d t a r g e t i t e m s ) . The reason here being t h a t the more items named, the i n c r e a s e d l i k e l i h o o d o f naming t a r g e t words due to chance. T h i s means t h a t a group naming more items may e x h i b i t an exaggerated l e v e l of memory Table 10 T y p i c a l i t y / D i v e r s i t y R a t i o f o r C a t e g o r i e s and Across Age- Groups . Subject Age-group Category 3-Years 4-Years 5-Years _M SD C l o t h e s 2.09* 4.26 3.29 3.21 1.09 T r a v e l 2.05 3.48 3.67 3.07 .88 Playground 1.27 1.87 1.98 1.71 .38 Zoo 1.54 1.70 1.40 1.55 .15 K i t c h e n 1.02 1.56 1.37 1.32 .27 Restaurant .70 1.45 1.34 1.16 .41 Toy .25 .41 .33 .33 .08 M 1.27 2.10 1.91 SD .68 1.31 1.18 *TDR = Index of Commonality R a t i o Type/Token R a t i o 56 Table 11 Tukey Comparisons: Mean D i f f e r e n c e s i n T y p i c a l i t y / d i v e r s i t y  R a t i o s For Each P a i r of C a t e g o r i e s . C l o t h e s T r a v e l P l a y g r d Zoo K i t c h e n R e s t r n t Toys Cl o t h e s 0.00 T r a v e l 0. 1 4 n s 0 .00 P l a y g r d 1. 5 0 n s 1 . 3 6 n s 0. 00 Zoo 1. 66* 1 . 5 2 n s 0. 1 6 n s 0. 00 K i t c h e n 1. 89* 1 .75 0. 3 9 n s 0. 2 3 n s 0. 00 R e s t r n t 2 . * * 05 1 .91* 0. 5 5n s 0. 3 9 n s 0. 1 6 n s 0.00 Toys 2. * * * 88 2 . 7 4 * * * 1. 3 8 n s 0. 9 9 n s 1. 2 2 n s 0.83 n s ns= non s i g n i f i c a n t ; * = p<.05.; ** = p<.01; *** = p<.001 57 performance compared to groups naming, on average, fewer items. Differences across categories. The various methods of assessing categories revealed several differences among them. These differences w i l l be discussed i n d i v i d u a l l y , and following each w i l l be a recommendation for which categories are best suited for a developmental priming study based on that method. One measure that varied s i g n i f i c a n t l y across categories was the average number of d i f f e r e n t items named per category (see Table 3 ) . Note, however, that these category differences were si m i l a r across the age-groups. This can be seen i n a ranking of the categories by the number of d i f f e r e n t items which was the same for a l l age-groups. In order from most d i f f e r e n t items to least, the ranking was TOYS, RESTAURANT, and PLAYGROUND. The categories KITCHEN and ZOO were invariably either fourth or f i f t h , and the TRAVEL and CLOTHES categories always had the fewest number of d i f f e r e n t items. The consistent ranking of categories with respect to the number of d i f f e r e n t items named suggests that the r e l a t i v e amount of knowledge or f a m i l i a r i t y with d i f f e r e n t categories was s i m i l a r across age-groups. In deciding which categories are best suited for a developmental priming study, one must keep two points in mind. F i r s t , categories with many d i f f e r e n t items may be too large; they may have few items that are t y p i c a l exemplars which make i t impossible for priming performance to r i s e above the f l o o r . Second, categories that consist of mainly t y p i c a l category exemplars ( i . e . , they are very small) w i l l r e s u l t i n too many target items being named i n the baseline condition. Such c e i l i n g e f f e c t s are not d e s i r a b l e f o r a pri m i n g study because ba s e r a t e s are too high t o d e t e c t an experimental e f f e c t . T h e r e f o r e , i f one i s u s i n g category s i z e t o s e l e c t c a t e g o r i e s f o r a developmental priming study, i t i s best t o s e l e c t c a t e g o r i e s t h a t are average i n s i z e . With t h i s c r i t e r i a I would s e l e c t the f o l l o w i n g c a t e g o r i e s : CLOTHES, KITCHEN, ZOO, and, PLAYGROUND. A second d i f f e r e n c e t h a t was found a c r o s s c a t e g o r i e s was t h e i r r a n k i n g w i t h r e s p e c t t o s i m i l a r i t y of response r a t e s a c r o s s age-groups. I determined t h i s degree o f s i m i l a r i t y by t a k i n g each category and c a l c u l a t i n g a Pearson c o r r e l a t i o n c o e f f i c i e n t based on the response r a t e s f o r two age-groups (see Table 5 ) . What I found was t h a t the c o r r e l a t i o n s r e v e a l e d no l a r g e age d i f f e r e n c e ; a category with the h i g h e s t c o r r e l a t i o n c o e f f i c i e n t between, f o r example, 3- and 4-year o l d s was u s u a l l y the same as t h a t with the h i g h e s t c o r r e l a t i o n c o e f f i c i e n t f o r 4- and 5- year o l d s . Since these c o r r e l a t i o n s were c a r r i e d out on response r a t e s , higher c o r r e l a t i o n s i n d i c a t e a g r e a t e r degree of s i m i l a r i t y i n responding between two age-groups. For t h i s reason, the four c a t e g o r i e s with the h i g h e s t c o r r e l a t i o n v a l u e s across a l l age-groups are the bes t s u i t e d f o r a developmental p r i m i n g study. T h e r e f o r e , by t h i s c r i t e r i o n , the c a t e g o r i e s b e s t s u i t e d f o r use i n a developmental priming study a r e : CLOTHES, PLAYGROUND, TRAVEL, and ZOO. A t h i r d d i f f e r e n c e a c r o s s the c a t e g o r i e s i s r e v e a l e d by the IC, TTR, and TDR va l u e s (see Tables 6, 8, and 10, r e s p e c t i v e l y ) . I have ranked the c a t e g o r i e s by these c r i t e r i a (averaged across the th r e e age-groups), with IC and TTR v a l u e s l i s t e d from l a r g e s t to s m a l l e s t , and TTR valu e s from s m a l l e s t t o l a r g e s t . Note t h a t except f o r the top and bottom c a t e g o r i e s , the rankings are d i f f e r e n t . IC Values CLOTHES (.663) PLAYGROUND(.643) TRAVEL (.625) RESTAURANT(.486) ZOO (-483) KITCHEN (.395) TOYS (-214) TTR Values TRAVEL (.213) CLOTHES (.216) KITCHEN (.305) ZOO (.307) PLAYGROUND(.383) RESTAURANT(.431) TDR Values CLOTHES (3.21) TRAVEL (3.07) PLAYGROUND(1.71) ZOO (1.55) KITCHEN (1.32) RESTAURANT(1.16) TOYS (0.33) TOYS (.661) Based on TDR va l u e s , the most a p p r o p r i a t e c a t e g o r i e s f o r developmental r e s e a r c h would be: CLOTHES, TRAVEL, PLAYGROUND, and ZOO. E v a l u a t i n g the d i f f e r e n t category assessment methods. S e v e r a l d i f f e r e n c e s were r e v e a l e d by the d i f f e r e n t category assessment methods. From these, d i f f e r e n t recommendations i n terms of which c a t e g o r i e s should be used i n a priming study were made. The methods and t h e i r r e s p e c t i v e recommendations were as f o l l o w s : Number of d i f f e r e n t items named — CLOTHES, KITCHEN, ZOO, and PLAYGROUND; response r a t e c o r r e l a t i o n s — CLOTHES, PLAYGROUND, TRAVEL, and ZOO; and t y p i c a l i t y / d i v e r s i t y r a t i o s — CLOTHES, TRAVEL, PLAYGROUND, ZOO. One way to determine which of these methods i s s u p e r i o r , i s t o v i s u a l l y examine the response d i s t r i b u t i o n s of each category, which are presented i n Appendix D. F i r s t we should examine the category CLOTHES because i t has c l e a r l y come out on top across a l l 60 methods and, t h e r e f o r e , i t can be used as an example of a 'good' c a t e g o r y . In examining the h i s t o g r a p h f o r CLOTHES i t i s apparent why i t has c o n s i s t e n t l y been at the top of a l l t h r e e l i s t s . F i r s t , i t s items cover a l l ranges of response r a t e s , with some items being named by almost a l l s u b j e c t s and some being named by very few. Second, the three age-group bars are of s i m i l a r h e i g h t s f o r each item; t h a t i s the response r a t e f o r each item i s f a i r l y c o n s i s t e n t a c r o s s age-groups. The next category t h a t should be assessed i s KITCHEN s i n c e i t was o n l y recommended once (by the method based on the number of d i f f e r e n t items named. In examining the h i s t o g r a p h f o r the category KITCHEN i t i s r e a d i l y apparent t h a t i t s d i s t r i b u t i o n i s q u i t e f l a t ; items do not range from high t o low response r a t e s , but c l u s t e r around the 20-30% response r a t e . While response r a t e s i n t h i s range are q u i t e s a t i s f a c t o r y f o r p r i m i n g s t u d i e s , t h e r e were c o n s i d e r a b l e age-group d i f f e r e n c e s t h a t are not d e s i r a b l e f o r developmental priming s t u d i e s . When IC v a l u e s were averaged across age-groups the category KITCHEN ranked second t o l a s t on t y p i c a l i t y ( f o l l o w e d by TOYS) which i s very low. The i n c o n s i s t e n c y a c r o s s age-groups i s a l s o apparent with the c o r r e l a t i o n s of response r a t e s on the 20 most o f t e n named items; c o r r e l a t i o n s ranged from .311 (between 4- and 5-year o l d s ) t o .451 (between 3- and 5-year o l d s ) . From t h i s I suggest t h a t a s s e s s i n g c a t e g o r i e s based on the number of d i f f e r e n t items i s i n s u f f i c i e n t , p a r t i c u l a r l y f o r a developmental study. The c h o i c e t h a t remains then i s between c o r r e l a t e d response r a t e s and TDR v a l u e s . Note t h a t both methods r e s u l t e d i n recommendations f o r the same c a t e g o r i e s . T h i s i s a very important p o i n t to c o n s i d e r because c o r r e l a t i o n c o e f f i c i e n t s are much e a s i e r t o compute than are TDR v a l u e s . I f there i s no q u a l i t a t i v e d i f f e r e n c e between the two methods, then c l e a r l y the c o r r e l a t i o n a l method i s p r e f e r a b l e . However, I do not t h i n k t h i s i s the case. In examining the h i s t o g r a p h s of the two c a t e g o r i e s , TRAVEL and PLAYGROUND, t h a t were ordered d i f f e r e n t l y f o r the two methods, one can see t h a t the former i s b e t t e r shaped than the l a t t e r ( i . e . , a more gradual d r o p - o f f from h i g h frequency items t o low frequency items; see Appendix D). The r e l a t i v e importance of t h i s d i f f e r e n c e c l e a r l y depends on the type of study f o r which the c a t e g o r i e s are needed. T h e r e f o r e , my recommendation i s t o use TDR v a l u e s f o r s e l e c t i n g c a t e g o r i e s i f the range of response r a t e s i s c r i t i c a l . However, i f a range of response r a t e s i s not c r i t i c a l , the c o r r e l a t i o n a l method i s s u f f i c i e n t . E v a l u a t i n g the age-group d i f f e r e n c e s . O v e r a l l , the r e s u l t s from the p r e s e n t study have i l l u s t r a t e d t h a t response d i s t r i b u t i o n s f o r word p r o d u c t i o n norms f o r seven c a t e g o r i e s range from f l a t t o skewed, with o n l y minor d i f f e r e n c e s among 3-, 4-, and 5-year o l d s . Three f a c t o r s may i n f l u e n c e the naming of items f o r the c a t e g o r i e s . The f i r s t , and probably most important, i s the c h i l d ' s growing vocabulary. Older c h i l d r e n know more words and, t h e r e f o r e , are l i k e l y to name more items o v e r a l l . Furthermore, o l d e r c h i l d r e n are more l i k e l y t o have g r e a t e r experience w i t h category exemplars than younger c h i l d r e n . T h i s may r e s u l t i n o l d e r c h i l d r e n naming a g r e a t e r v a r i e t y of exemplars because of t h e i r exposure, or fewer and more t y p i c a l exemplars because of repeated exposure t o the items. The second f a c t o r a f f e c t i n g response r a t e s i n category p r o d u c t i o n t a s k s i s t h a t as language i s used more f o r communication, the p r e s c h o o l e r may be more l i k e l y t o i n c o r p o r a t e knowledge of p r o t o t y p i c a l i n f o r m a t i o n and category boundaries. T h e r e f o r e , s i n c e 3-year o l d s are l e s s l i k e l y t o know category boundaries, they may g i v e a g r e a t e r v a r i e t y of responses. As a r e s u l t , and i n c o n t r a s t t o the e f f e c t of the l a r g e r vocabulary on response r a t e s , i n c r e a s i n g category knowledge may r e s u l t i n more uniform responses. However, t h i s was not the case with the present study s i n c e the average t y p i c a l i t y value a c r o s s c a t e g o r i e s f o r the 3-year o l d s was .428. T h i s was much l e s s than the average t y p i c a l i t y r a t i n g s f o r 4- and 5- year o l d s which were .559 and .517, r e s p e c t i v e l y . The 3-year o l d s a l s o averaged h i g h e r d i v e r s i t y r a t i n g s — .403 compared t o .334 and .341 f o r 4- and 5-year o l d s , r e s p e c t i v e l y . A t h i r d f a c t o r t h a t may be i n v o l v e d i n response r a t e s from c a t e g o r y p r o d u c t i o n t e s t s i s the s i z e of the category. For example, even though c h i l d r e n t y p i c a l l y have a l o t of experience with items from the category TOY, t h i s category had a very low TDR v a l u e ; TOY had the lowest o v e r a l l t y p i c a l i t y r a t i n g (.214 as compared t o the h i g h e s t which was .663) and the h i g h e s t o v e r a l l d i v e r s i t y r a t i n g (.661 as compared t o the lowest which was .213). One reason f o r t h i s f l a t response d i s t r i b u t i o n may be t h a t the category i s f a r too l a r g e f o r t y p i c a l i t y t o occur because c h i l d r e n are exposed t o many d i f f e r e n t t o y s . I t i s p o s s i b l e t h a t f o r a l a r g e r category, many more exposures are r e q u i r e d f o r the development of t y p i c a l i t y . That i s , i f an i n d i v i d u a l i s exposed t o a l a r g e number of items, f o r any of the items t o stand out the i n d i v i d u a l must be exposed t o t h a t item f a r more than he/she would i f the item was from a category with fewer items. I f t h i s i s the case, then one would expect t h a t with i n c r e a s i n g age even extremely l a r g e c a t e g o r i e s would have a skewed response d i s t r i b u t i o n . T h i s r e q u i r e s i n v e s t i g a t i o n with o l d e r c h i l d r e n and/or a d u l t s . Conclusion C a t e g o r i e s t h a t have s i m i l a r response r a t e s a c r o s s age-groups are p r e f e r r e d f o r developmental s t u d i e s because they a l l o w f o r more meaningful comparisons across the age-groups. Furthermore, f o r priming s t u d i e s i t i s p r e f e r r e d t o use c a t e g o r i e s t h a t are i n t e r m e d i a t e i n t y p i c a l i t y and d i v e r s i t y t o av o i d c e i l i n g and f l o o r e f f e c t s . For t h i s reason i t was recommended t h a t c a t e g o r i e s with higher TDR va l u e s are s e l e c t e d f o r priming s t u d i e s because t h i s value takes i n t o account both the t y p i c a l i t y and d i v e r s i t y of category exemplars. I f the TDRs are averaged a c r o s s the age-groups then one i s a l s o more l i k e l y t o s e l e c t c a t e g o r i e s t h a t have s i m i l a r response r a t e s a c r o s s the age-groups. The fo u r of the seven c a t e g o r i e s examined i n the presen t study having the h i g h e s t TDR va l u e s and, t h e r e f o r e , the bes t mixture of t y p i c a l i t y and d i v e r s i t y , are CLOTHES, TRAVEL, PLAYGROUND, and ZOO. As a r e s u l t , these f o u r c a t e g o r i e s were s e l e c t e d f o r use i n the pri m i n g study t h a t i s presented i n the next chapter. 64 Chapter Four STUDY 2 — IMPLICIT AND EXPLICIT MEMORY IN PRESCHOOLERS: WHEN 3-YEAR OLDS REMEMBER AS MUCH AS 5-YEAR OLDS. Over the l a s t decade, a l a r g e number of s t u d i e s have shown t h a t i m p l i c i t and e x p l i c i t memory can f u n c t i o n independently of each o t h e r . One c r i t i c a l o b s e r v a t i o n i s t h a t these two forms of memory develop d i f f e r e n t l y across the l i f e span. E x p l i c i t memory i s ac q u i r e d i n e a r l y c h i l d h o o d , remains s t a b l e a c r o s s adulthood, and then decreases i n l a t e r l i f e ( S althouse, 1982). Conversely, i m p l i c i t memory develops e a r l i e r i n c h i l d h o o d and remains i n t a c t w e l l i n t o l a t e adulthood ( f o r review see Graf, 1990). To e x p l a i n t h i s p a t t e r n of r e s u l t s , i t has been suggested t h a t i m p l i c i t memory performance i s mediated by automatic processes t h a t are i n i t i a t e d and guided p r i m a r i l y by e x t e r n a l f a c t o r s — the t e s t s i t u a t i o n , whereas e x p l i c i t memory performance i s mediated by p r o c e s s i n g t h a t i s c o n t r o l l e d by s u b j e c t s ' g oals and s t r a t e g i e s (e.g., C r a i k , 1983). T h e r e f o r e , the more developed a s u b j e c t ' s c o n t r o l l e d p r o c e s s e s — such as memory a b i l i t i e s and s t r a t e g i e s — the b e t t e r t h e i r e x p l i c i t memory performance. Furthermore, s i n c e c o g n i t i v e a b i l i t i e s such as these g e n e r a l l y improve with i n c r e a s i n g age, e x p l i c i t memory t e s t performance should a l s o i n c r e a s e w i t h age. Conversely, i f i m p l i c i t memory i s mediated by automatic processes, i t should not be a f f e c t e d by any changes i n c o n t r o l l e d processes, but by the pe r c e p t u a l aspects of the t e s t i n g s i t u a t i o n . For example, when one has reached the p o i n t a t which r e a d i n g i s automatic, how w e l l they read i s more determined by the p e r c e p t i o n o f the t e x t : I f i t i s u n c l e a r or upside down they w i l l read slower — and l i k e l y remember more -- than i f the t e x t appeared normal. C l e a r l y , t h i s e f f e c t i s not due t o the s u b j e c t ' s a b i l i t i e s (although they may change with p r a c t i c e ) , but due to the t e s t s i t u a t i o n . Furthermore, automatic processes are t y p i c a l l y more b a s i c than c o n t r o l l e d processes which means t h a t , u n l i k e e x p l i c i t memory performance, i m p l i c i t memory performance i s mediated by processes t h a t are i n t a c t v ery e a r l y i n l i f e . T h i s means t h a t performance on these t e s t s should not be a f f e c t e d by a g e - r e l a t e d i n c r e a s e s t y p i c a l l y found with t e s t s o f e x p l i c i t memory performance. In l i g h t of t h i s , i t i s expected t h a t i m p l i c i t memory t e s t performance w i l l be c o n s i s t e n t across the l i f e - s p a n with performance being a f f e c t e d more by the s p e c i f i c t e s t s i t u a t i o n . To i n v e s t i g a t e these p o s s i b i l i t i e s , I examined the e f f e c t of task induced e l a b o r a t i v e p r o c e s s i n g on i m p l i c i t and e x p l i c i t memory i n 3-, 4-, and 5-year o l d p r e s c h o o l e r s . T h i s was done by p r e s e n t i n g s u b j e c t s with v a r i o u s items and having them study some e l a b o r a t i v e l y , and some n o n - e l a b o r a t i v e l y . E l a b o r a t i v e study c o n d i t i o n s i n v o l v e d a s k i n g the c h i l d t o name the t a r g e t item and a yes/no q u e s t i o n about the item, whereas the non-e l a b o r a t i v e c o n d i t i o n i n v o l v e d only a s k i n g the c h i l d t o name the item. A f t e r a c h i l d s t u d i e d the items, I t e s t e d t h e i r i m p l i c i t and e x p l i c i t memory performance with a category p r o d u c t i o n t e s t and a category c u e d - r e c a l l t e s t , r e s p e c t i v e l y . The q u e s t i o n I have addressed i s whether t h i s development of c o g n i t i v e a b i l i t i e s has the same e f f e c t o r d i f f e r e n t e f f e c t s on 66 i m p l i c i t and e x p l i c i t memory t e s t performance. Method Performance on the e x p l i c i t memory t e s t i n the pr e s e n t study was assessed i n terms of the p r o p o r t i o n o f t a r g e t items r e c a l l e d . Performance on the i m p l i c i t memory t e s t s was assessed i n terms of priming. C r i t i c a l t o priming s t u d i e s i s t h a t b a s e r a t e performance i s a t a l e v e l s u f f i c i e n t f o r c a r r y i n g out meaningful comparisons. The study d e s c r i b e d i n Chapter 3 i n v o l v e d a c o l l e c t i o n of base r a t e data on seven c a t e g o r i e s (see m a t e r i a l s s e c t i o n ) t o ensure adequate l e v e l s of base r a t e performance f o r the present study. The s e l e c t i o n of category exemplars f o r p r i m i n g s t u d i e s i s t y p i c a l l y based on the f o l l o w i n g c r i t e r i a . F i r s t , b a s e r a t e performance on t a r g e t s must not be a t c e i l i n g (100%) or, second, on the f l o o r ( 0 % ) . I f base r a t e naming of t a r g e t items i s a t c e i l i n g then there i s no p o s s i b i l i t y f o r i n c r e a s i n g t a r g e t naming i n the experimental c o n d i t i o n , and thus, no priming can occur. I f baserate naming of t a r g e t s i s on the f l o o r then priming w i l l be d i f f i c u l t t o d e t e c t because w h i l e study may boost the naming of t a r g e t items, t h i s boost may not be s u f f i c i e n t t o l i f t performance o f f the f l o o r . A developmental study imposes an a d d i t i o n a l important c r i t e r i a f o r the s e l e c t i o n of m a t e r i a l s : T a r g e t items must have roughly the same p r o d u c t i o n r a t e s a c r o s s age-groups. D i f f e r e n t p r o d u c t i o n r a t e s c o u l d r e f l e c t d i f f e r e n c e s i n c h i l d r e n ' s f a m i l i a r i t y w i t h words, and such d i f f e r e n c e s might i n f l u e n c e the p a t t e r n of priming. On the b a s i s of these c r i t e r i a , f o u r c a t e g o r i e s and f i v e items from each categ o r y were s e l e c t e d f o r 67 use as study m a t e r i a l s . M a t e r i a l s . Study m a t e r i a l s c o n s i s t e d of 20 black and white l i n e drawings, each glued t o an 8 by 5 i n c h index c a r d . These items belonged t o four of the seven c a t e g o r i e s from which norms were c o l l e c t e d i n Chapter 3. The f o u r c a t e g o r i e s and the s e l e c t e d t a r g e t items are as f o l l o w s : CLOTHES (dress, hat, shoe, s h o r t s , and underwear); MODES OF TRANSPORTATION ( b i c y c l e , bus, t r a i n , t r u c k , and van); PLAYGROUND ITEMS (bridge, c l i m b e r , merry-go-round, t e e t e r - t o t t e r , and t i r e s ) ; and ZOO ANIMALS (bear, g i r a f f e , kangaroo, monkey, t i g e r ) . Each item was s e l e c t e d from the norms i n Chapter 3 according t o thr e e c r i t e r i a : frequency of occurrence i n the norms was not a t f l o o r ( i . e . , not l e s s than 10%) or c e i l i n g ( i . e . , not more than 60%), occurrence frequencies were s i m i l a r across age groups, and each item was r e p r e s e n t a b l e as a p i c t u r e (the s e l e c t e d m a t e r i a l s are i n Appendix E ) . S u b j e c t s . S u b j e c t s were p r e s c h o o l e r s from Vancouver area daycare c e n t e r s . There were 12 c h i l d r e n i n each group of 3-year o l d s (Mean = 3.66 years; range = 3.33 t o 3.92 y e a r s ) , 4-year o l d s (Mean = 4.42 years; range = 4.0 t o 4.83 y e a r s ) , and 5-year o l d s (Mean = 5.35; range = 5.0 t o 5.92 y e a r s ) . Procedure. There were three phases i n the experiment: i n s t r u c t i o n , study, and t e s t . During the i n s t r u c t i o n phase s u b j e c t s were t o l d t h a t they would be shown some p i c t u r e s and asked one or two q u e s t i o n s about each p i c t u r e . They were a l s o t o l d t h a t a f t e r l o o k i n g a t the p i c t u r e s a few s t o r i e s would be read t o them f o l l o w e d by a question t h a t would h e l p them t o f i n i s h the s t o r y . The c h i l d r e n were not informed about the 68 l a t e r memory t e s t s . During the study phase s u b j e c t s were presented with t en items ( f i v e items from each of two c a t e g o r i e s ) . F i v e of the items, those from one category, were pre s e n t e d i n a c o n d i t i o n ( n o n - e l a b o r a t i v e ) t h a t r e q u i r e d naming each p i c t u r e ; the o t h e r f i v e items were presented i n a c o n d i t i o n ( e l a b o r a t i v e ) t h a t asked q u e s t i o n s f o c u s s i n g on r e a l - l i f e a spects/uses of the item (e.g., "Do boys wear d r e s s e s ? 1 1 ; f o r q u e s t i o n s see Appendix E) . The s e t of 10 items was presented i n an a l t e r n a t i n g f a s h i o n so t h a t f i r s t an item was from one category, and the second item was from the other category, and so on. T h i s method ensured t h a t when s u b j e c t s were presented with an item t h a t was i n , f o r example, the e l a b o r a t i v e study c o n d i t i o n , the next item would be one from the n o n - e l a b o r a t i v e study c o n d i t i o n . The order o f the items w i t h i n each category was random. Across s u b j e c t s , c o u n t e r b a l a n c i n g ensured t h a t a l l items were s t u d i e d i n each experimental c o n d i t i o n e q u a l l y o f t e n . For each s u b j e c t , the items from two c a t e g o r i e s were not pres e n t e d f o r study; they were used t o assess b a s e r a t e performance. A c r o s s s u b j e c t s , each category was used e q u a l l y o f t e n i n the experimental and baserate c o n d i t i o n s . The t e s t phase immediately f o l l o w e d the study phase. The category p r o d u c t i o n t e s t was given f i r s t ; i t i n v o l v e d f o u r t r i a l s , one f o r each category. For each t r i a l , the experimenter read a b r i e f s t o r y r e l e v a n t t o one of the c a t e g o r i e s (see Appendix A) and then asked a q u e s t i o n r e q u i r i n g the s u b j e c t t o name items from the cat e g o r y . For example, f o r the category ZOO ANIMALS the s t o r y was about a l i t t l e b o y / g i r l t h a t v i s i t e d the zoo. A f t e r hearing the s t o r y , the c h i l d was asked what k i n d of animals he/she thought the p r o t a g o n i s t of the s t o r y saw a t the zoo. The c h i l d was encouraged t o name up t o 5 items per category. I f a s u b j e c t had d i f f i c u l t y producing 5 items then an a l t e r n a t i v e question was used t o encourage naming items (see Appendix A ) . Regardless of how few items were produced, a f t e r r e a d i n g the a l t e r n a t i v e q u e s t i o n s , the experimenter went on t o the next s t o r y . Two of the t e s t t r i a l s focused on s t u d i e d c a t e g o r i e s and two focused on baserate c a t e g o r i e s . They were always administered i n the f o l l o w i n g o r d e r : Baserate (non-studied c a t e g o r y ) , s t u d i e d category ( e l a b o r a t i v e ) , b aserate, and s t u d i e d category (non-e l a b o r a t i v e ). The l a s t p a r t of the t e s t phase c o n s i s t e d o f category c u e d - r e c a l l t e s t s . C u e d - r e c a l l of items from the two s t u d i e d c a t e g o r i e s was always assessed immediately a f t e r category p r o d u c t i o n . The t e s t began with i n s t r u c t i o n s , f o r example, "A l i t t l e while ago you saw some p i c t u r e s of animals t h a t you might see i n a zoo. What were the names of those animals you saw? 1 1. T h i s q u e s t i o n was repeated i f there was no response a f t e r about 30 seconds. I f r e p e a t i n g the q u e s t i o n d i d not e l i c i t a response a f t e r another 30 seconds the q u e s t i o n i n g procedure was repeated f o r the second category. Sessions l a s t e d about 15-20 minutes f o r each s u b j e c t . R e s u l t s The c r i t i c a l dependent measures were the p r o p o r t i o n of t a r g e t items named on the category c u e d - r e c a l l t e s t s and the p r o p o r t i o n of t a r g e t items named on the category p r o d u c t i o n t e s t s . The c r i t i c a l alpha l e v e l was s e t a t .05 u n l e s s otherwise s t a t e d . A l l a n a l y s i s of v a r i a n c e t a b l e s are presented i n Appendix F. The main f i n d i n g s from the category-cued r e c a l l t e s t s and the category p r o d u c t i o n t e s t s are shown i n F i g u r e 1 and 2, r e s p e c t i v e l y . The f i g u r e s h i g h l i g h t the f a c t t h a t o v e r a l l performance was h i g h e r i n the e l a b o r a t i v e than n o n - e l a b o r a t i v e study c o n d i t i o n on both the i m p l i c i t and e x p l i c i t memory t e s t s . An o v e r a l l a n a l y s i s of v a r i a n c e (ANOVA) of these f i n d i n g s , u s i n g age as a between-subjects f a c t o r and study and t e s t as the w i t h i n - s u b j e c t s f a c t o r s , showed a marginal t r i p l e i n t e r a c t i o n , F(2,33) = 2.452, MS C = 465.638, p=.10. For t h i s reason, the r e s u l t s from each t e s t type were analyzed s e p a r a t e l y . The e x p l i c i t memory r e s u l t s are presented i n F i g u r e 1. T h i s f i g u r e h i g h l i g h t s two p o i n t s . F i r s t , i n the non-e l a b o r a t i v e study c o n d i t i o n e x p l i c i t memory performance i n c r e a s e s across age groups. Second, i n the e l a b o r a t i v e study c o n d i t i o n 3-year o l d s performed almost as w e l l as 5-year o l d s , thereby e l i m i n a t i n g the a g e - e f f e c t t h a t i s t y p i c a l of e x p l i c i t memory performance. An ANOVA of the r e c a l l t e s t data showed a s i g n i f i c a n t main e f f e c t f o r age, F = 8.544, MS C = 650.848, p<.001, with 5-year o l d s r e c a l l i n g a higher p r o p o r t i o n of t a r g e t items o v e r a l l (83.17%) than 4-year o l d s (64.08%), and 4-year o l d s r e c a l l i n g a h i g h e r p r o p o r t i o n of t a r g e t items than 3-year o l d s (53.08%). There was a l s o a s i g n i f i c a n t main e f f e c t due t o study t a s k s , F = 4.158, MS C = 917.081, w i t h more t a r g e t words r e c a l l e d i n the e l a b o r a t i v e c o n d i t i o n (74.06%) than i n Figure 1 The Mean Propor t i o n of Target Words R e c a l l e d Across Age-groups. A G E STUDY TASKS El a b o r a t i v e N o n - e l a b o r a t i v e the n o n - e l a b o r a t i v e c o n d i t i o n (59.50%). More i m p o r t a n t l y , t h e r e was a s i g n i f i c a n t age x study task i n t e r a c t i o n , F(2,33) = 3.615, MS C = 917.081. Simple main e f f e c t s a n a l y s e s r e v e a l e d a s i g n i f i c a n t age e f f e c t o n l y i n the n o n - e l a b o r a t i v e study c o n d i t i o n , F(2,66) = 10.427, MS C = 783.965, p<.01, with 5-year o l d s r e c a l l i n g more t a r g e t items (84.50%) than 4-year o l d s (61.58%), and 4-year o l d s r e c a l l i n g more t a r g e t items than 3-year o l d s (32.47%). There was a l s o a s i g n i f i c a n t e f f e c t due t o study t a s k s with 3-year o l d s , F ( l , 3 3 ) = 11.176, MSe = 917.081, p<.01, who r e c a l l e d more t a r g e t items i n the e l a b o r a t i v e c o n d i t i o n (73.75%) than i n the n o n - e l a b o r a t i v e c o n d i t i o n (32.42%). The e f f e c t due t o the study t a s k was not s i g n i f i c a n t from the o t h e r age groups. T h i s p a t t e r n of performance i n the n o n - e l a b o r a t i v e study c o n d i t i o n supports the general f i n d i n g t h a t e x p l i c i t memory i n c r e a s e s through the p r e s c h o o l p e r i o d . More im p o r t a n t l y , performance i n the e l a b o r a t i v e study c o n d i t i o n suggests t h a t 3-year o l d s do not spontaneously e l a b o r a t i v e l y process to-be-remembered m a t e r i a l s , but when e l a b o r a t i o n of m a t e r i a l s i s engaged by means of a study task, they p r o f i t from i t and can perform as w e l l as 4- and 5-year o l d s . F i g u r e 2 p r e s e n t s three d i f f e r e n t measures of performance from categ o r y p r o d u c t i o n t e s t s . The bottom Tine i s b a s e l i n e performance which i s the p r o p o r t i o n of t a r g e t items named per category i n the absence of p r i o r study. The upper two l i n e s show performance i n the e l a b o r a t i v e and n o n - e l a b o r a t i v e study c o n d i t i o n s . I t i s the d i f f e r e n c e between the s e two l i n e s and the bottom l i n e ( b a s e l i n e ) t h a t i n d i c a t e s the amount of priming 73 F i g u r e 2 The Mean P r o p o r t i o n of Target Words Produced Across Age-groups. STUDY T A S K S 0 0 Elaborative A A Non-elaborative • Baseline ( d i f f e r e n c e between b a s e l i n e and experimental performance). The d i f f e r e n t l e v e l s of priming shown i n F i g u r e 2 i n d i c a t e the d i f f e r e n c e between naming of t a r g e t s i n the experimental c o n d i t i o n and naming of t a r g e t s i n the b a s e l i n e c o n d i t i o n (without p r i o r study of p i c t u r e s of the t a r g e t s ) . The f i g u r e shows t h a t t h e r e was p r i m i n g i n a l l experimental c o n d i t i o n s , and by a l l s u b j e c t groups. Furthermore, p r i m i n g was s i m i l a r a cross age-groups. An ANOVA of the p r i m i n g data r e v e a l e d a s i g n i f i c a n t main e f f e c t due t o study t a s k s , F_ = 7.537, MSC = 293.367, p=.009, wit h more priming i n the e l a b o r a t i v e study c o n d i t i o n (20.46%) than i n the n o n - e l a b o r a t i v e study c o n d i t i o n (9.38%), w i t h no o t h e r e f f e c t s approaching s i g n i f i c a n c e . The l a c k of an e f f e c t due t o age i n d i c a t e d t h a t was the same across age-groups and t h a t f o r a l l age-groups i t was h i g h e r i n the e l a b o r a t i v e than i n the n o n - e l a b o r a t i v e study c o n d i t i o n . These data support the g e n e r a l f i n d i n g t h a t i m p l i c i t memory performance does not i n c r e a s e with age. But, more importantly, these data p r o v i d e evidence t h a t i m p l i c i t memory can be a f f e c t e d by a study m a n i p u l a t i o n . S p e c i f i c a l l y , t h e r e was priming when s u b j e c t s were simply exposed t o the m a t e r i a l s and asked t o name them, and priming was h i g h e r when s u b j e c t s were r e q u i r e d t o p r o c e s s the m a t e r i a l s more e l a b o r a t i v e l y . GENERAL DISCUSSION The p r e s e n t experiment examined the e f f e c t s of e l a b o r a t i v e and n o n - e l a b o r a t i v e study t a s k s on e x p l i c i t ( category cued-r e c a l l ) and i m p l i c i t memory (category p r o d u c t i o n ) t e s t performance. Category c u e d - r e c a l l t e s t performance showed a s i g n i f i c a n t a g e - r e l a t e d i n c r e a s e i n the n o n - e l a b o r a t i v e study c o n d i t i o n , but no d i f f e r e n c e s a c r o s s age-groups when m a t e r i a l s were s t u d i e d e l a b o r a t i v e l y . Category p r o d u c t i o n t e s t performance showed h i g h e r amounts of priming i n the e l a b o r a t i v e study c o n d i t i o n than i n the n o n - e l a b o r a t i v e study c o n d i t i o n . The c u e d - r e c a l l t e s t r e s u l t s from the n o n - e l a b o r a t i v e study c o n d i t i o n are c o n s i s t e n t with the general f i n d i n g t h a t e x p l i c i t memory t e s t performance i n c r e a s e s d u r i n g the e a r l y p r e - s c h o o l years (e.g., K a i l , 1979). I t i s i n t e r e s t i n g t o note, however, t h a t i n the e l a b o r a t i v e study c o n d i t i o n e x p l i c i t memory t e s t performance d i d not change across the age-groups. T h i s l a c k of an a g e - e f f e c t i n d i c a t e s t h a t the study t a s k engages a c e r t a i n type of p r o c e s s i n g which d i m i n i s h e s age-e f f e c t s . I t appears t h a t younger p r e s c h o o l e r s do not spontaneously engage i n t h i s type of p r o c e s s i n g when l e f t to t h e i r own d e v i c e s . The i m p l i c i t memory t e s t r e s u l t s are c o n s i s t e n t with the l i t e r a t u r e (e.g., Greenbaum & Graf, 1989) t o the extent t h a t p r i m i n g was s i m i l a r a c r o s s the age groups. Because priming was the same acr o s s age-groups, the r e s u l t s support the hyp o t h e s i s t h a t priming depends on processes t h a t are a l r e a d y w e l l developed i n young p r e s c h o o l e r s . Although these processes seem t o be i n t a c t very e a r l y and thus, q u i t e b a s i c , i t does not f o l l o w t h a t they are e n t i r e l y automatic i n nature. T h i s p o i n t i s underscored by the f i n d i n g t h a t priming was h i g h e r i n the e l a b o r a t i v e than i n the n o n - e l a b o r a t i v e study c o n d i t i o n . The reason i n g here i s t h a t e l a b o r a t i v e p r o c e s s i n g i s a c o n t r o l l e d t a s k , not automatic, and because i t a f f e c t e d i m p l i c i t memory performance i t f o l l o w s t h a t i m p l i c i t memory i s mediated t o some extent by c o n t r o l l e d p r o c e s s i n g . While 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 some f i n d i n g s i n the l i t e r a t u r e t h a t i m p l i c i t memory i n young c h i l d r e n i s u n a f f e c t e d by e l a b o r a t i v e p r o c e s s i n g ( N a i t o , i n p r e s s ) , note t h a t the N a i t o ( i n press) study d i d not examine c h i l d r e n as young as 3-years o l d . However, the study e f f e c t on pr i m i n g i s c o n s i s t e n t with the r e s u l t s found i n s t u d i e s on new a s s o c i a t i o n s (e.g., Schacter & Graf, 1986). These s t u d i e s found i n c r e a s e d priming when new a s s o c i a t i o n s were s t u d i e d e l a b o r a t i v e l y . To understand these r e s u l t s , we must f i r s t c o n s i d e r what aspects of memory develop d u r i n g the p r e s c h o o l p e r i o d . One i s the growing f a m i l i a r i t y with words and vocabulary s i z e i n terms of what can be a c t i v a t e d a u t o m a t i c a l l y . I n t u i t i v e l y , i t would make sense t h a t i m p l i c i t memory performance should i n c r e a s e a c r o s s the l i f e - s p a n i f t h e r e are more r e p r e s e n t a t i o n s t h a t can be a c t i v a t e d a u t o m a t i c a l l y . However, most s t u d i e s assess i m p l i c i t memory i n terms of p r i m i n g and s i n c e priming c o n s i s t s of s u b t r a c t i n g baserate performance from experimental performance, t h i s method of a s s e s s i n g i m p l i c i t memory performance e l i m i n a t e s a g e - r e l a t e d d i f f e r e n c e s i n vocabulary s i z e as w e l l as knowledge base. Note t h a t t h i s i s not the case with e x p l i c i t memory performance. From t h i s , one should c o n s i d e r t o what extent the a g e - r e l a t e d change seen i n e x p l i c i t memory performance i s r e l a t e d t o a growing knowledge base which i n c r e a s e s paths t o the words making r e c a l l i n g t a r g e t items e a s i e r . A second aspect o f memory development t h a t i s a c q u i r e d d u r i n g the p r e s c h o o l p e r i o d i s proc e s s e s t h a t are s e l f -i n i t i a t e d and guided. T h i s development i s important t o note because as a c h i l d ' s a b i l i t y t o c o n t r o l t h i s p r o c e s s i n g i n c r e a s e s , so w i l l t h e i r performance on t a s k s t h a t r e q u i r e c o n t r o l l e d p r o c e s s i n g . By t h i s view, the f a c t t h a t e x p l i c i t memory t e s t performance i n c r e a s e s w i t h age supports the hypothesis t h a t e x p l i c i t memory i s mediated by c o n t r o l l e d p r o c e s s i n g . The present study a l s o supports t h i s h y p o t h e s i s . S p e c i f i c a l l y , when i t i s not necessary t h a t a s u b j e c t can s e l f -i n i t i a t e c o n t r o l l e d p r o c e s s i n g (when the s u b j e c t i s engaged i n e l a b o r a t i v e p r o c e s s i n g by the nature of the task) 3-year o l d s ' performance was comparable with t h a t of 5-year o l d s . The absence of i n c r e a s e d performance f o r the two study c o n d i t i o n s f o r 4- and 5-year o l d s may be e x p l a i n e d by the f a c t t h a t c h i l d r e n i n t h i s age range, t o some extent, e l a b o r a t i v e l y process m a t e r i a l s spontaneously. I f the e l a b o r a t i v e study c o n d i t i o n was more extensive than answering a yes/no q u e s t i o n about a t a r g e t item, then the o l d e r p r e s c h o o l e r s ' performance would l i k e l y have a l s o been h i g h e r i n the e l a b o r a t i v e than i n the n o n - e l a b o r a t i v e study c o n d i t i o n . The c o n s i s t e n t and i n c o n s i s t e n t f i n d i n g s from the i m p l i c i t memory t e s t performance can be e x p l a i n e d i n terms of automatic processes. Note t h a t automatic processes, by t h e i r nature, are not a f f e c t e d by c o n t r o l l e d processes. By t h i s view, i t f o l l o w s t h a t the degree t o which a c h i l d ' s c o n t r o l l e d processes are developed should not a f f e c t the automatic p r o c e s s e s . T h i s means t h a t i f i m p l i c i t memory t e s t performance i s mediated by automatic p r o c e s s e s , t h e r e should be no age d i f f e r e n c e s i n priming a c r o s s the age groups, as was the case with the pr e s e n t 78 experiment. T h i s argument a l s o extends t o the study m a n i p u l a t i o n o f a c o n t r o l l e d p r o c e s s . S p e c i f i c a l l y , the e l a b o r a t i v e v e r s u s n o n - e l a b o r a t i v e study c o n d i t i o n s ( c o n t r o l l e d process) s h o u l d not a f f e c t i m p l i c i t memory t e s t performance (automatic p r o c e s s ) . T h i s was not the f i n d i n g i n the experiment as performance was c o n s i s t e n t l y h i g h e r i n the e l a b o r a t i v e than i n the n o n - e l a b o r a t i v e study c o n d i t i o n s . Does t h i s mean t h a t i m p l i c i t memory t e s t performance i s mediated by c o n t r o l l e d processes? To answer t h i s I w i l l r e f e r t o a study by Schacter and Graf (1986) t h a t found i m p l i c i t memory t e s t performance t o be a f f e c t e d by e l a b o r a t i v e p r o c e s s i n g . I reviewed t h i s study i n Chapter two, and thus, w i l l g i v e o n l y a b r i e f summary here. In t h i s study, Schacter and Graf (1986) manipulated e l a b o r a t i v e p r o c e s s i n g by having s u b j e c t s study new a s s o c i a t i o n s (a p a i r of words t h a t are not normally a s s o c i a t e d ; e.g., OFFICER-FLOWER) a t d i f f e r e n t l e v e l s of p r o c e s s i n g ( i . e . , g e n e r a t i n g words/sentences, r e a d i n g meaningful or anomalous words/sentences, or r a t i n g p l e a s a n t n e s s of words/sentences). They t e s t e d i m p l i c i t and e x p l i c i t memory performance with word completion and c u e d - r e c a l l t e s t s , r e s p e c t i v e l y . Schacter and Graf (1986) r e p o r t e d two major f i n d i n g s . F i r s t , both i m p l i c i t and e x p l i c i t memory performance f o r new a s s o c i a t i o n s depended on e l a b o r a t i v e p r o c e s s i n g . That i s , i f m a t e r i a l s were not processed e l a b o r a t i v e l y , s u b j e c t s d i d not name the new a s s o c i a t i o n s above chance l e v e l s . Second, o n l y e x p l i c i t memory performance b e n e f i t t e d from a more e x t e n s i v e e l a b o r a t i o n of meaningful r e l a t i o n s . Schacter and Graf (1986) concluded t h a t the f i r s t r e s u l t i n d i c a t e s an u n d e r l y i n g commonality wi t h r e s p e c t t o the r e p r e s e n t a t i o n i n v o l v e d i n both types of memory. Based on the l a t t e r r e s u l t , however, they hypothesized t h a t " i m p l i c i t and e x p l i c i t memory f o r new a s s o c i a t i o n s depend on d i s t i n c t and d i s s o c i a b l e components of the r e p r e s e n t a t i o n e s t a b l i s h e d by e l a b o r a t i v e p r o c e s s i n g " . How i s the Schacter and Graf (1986) study r e l e v a n t t o the present study? The con n e c t i o n has t o do with the age of the s u b j e c t s and t h a t f a c t t h a t d u r i n g the p r e s c h o o l years c h i l d r e n a c q u i r e new words a t a r a p i d r a t e . For these c h i l d r e n , many of the study l i s t items and t h e i r corresponding names are new or a t l e a s t not h i g h l y f a m i l i a r . In the Schacter and Graf (1986) study t h e r e was no memory f o r new a s s o c i a t i o n s without e l a b o r a t i v e p r o c e s s i n g . In the present study, t h e r e was some priming even without e l a b o r a t i v e s t u d y - t r i a l p r o c e s s i n g perhaps because the items were n e i t h e r very u n f a m i l i a r (new), nor very f a m i l i a r (old) t o a l l s u b j e c t s . T h e r e f o r e , the present r e s u l t s r e f l e c t what one might expect with items o f i n t e r m e d i a t e f a m i l i a r i t y or with a mixture of f a m i l i a r and new items. I f the items were s t r i c t l y 'new', we would have expected no priming i n the n o n - e l a b o r a t i v e c o n d i t i o n . But, t h i s was not the case. In summary, the p r e s e n t experiment p r o v i d e d s u p p o r t i n g evidence t h a t t h e r e are important d i s t i n c t i o n s between i m p l i c i t and e x p l i c i t memory t e s t performance. I t i l l u s t r a t e d t h a t while there may be some o v e r l a p of the components u n d e r l y i n g these two forms of memory performance, t h e r e are s i g n i f i c a n t d i f f e r e n c e s r e g a r d i n g o t h e r u n d e r l y i n g processes, p a r t i c u l a r 80 those used i n r e t r i e v a l . S p e c i f i c a l l y , the experiment supports the h y p othesis put f o r t h i n the Schacter and Graf (1986) paper t h a t e l a b o r a t i v e p r o c e s s i n g e s t a b l i s h e s a r e p r e s e n t a t i o n of the t a r g e t item ( s t o r a g e ) , but i m p l i c i t and e x p l i c i t memory performance depend on d i f f e r e n t components of t h a t r e p r e s e n t a t i o n a t r e t r i e v a l . 81 Chapter 5 DISCUSSION The o v e r a l l g o a l of t h i s t h e s i s was t o assess the pre s c h o o l p e r i o d development of i m p l i c i t and e x p l i c i t memory. The focus was on the f o l l o w i n g q u e s t i o n s : How does i m p l i c i t memory develop d u r i n g t h i s time, and how i s i t a f f e c t e d by a l e v e l s of p r o c e s s i n g manipulation? How does e x p l i c i t memory develop d u r i n g the p r e s c h o o l y e a r s , and how i s i t a f f e c t e d by a l e v e l s of p r o c e s s i n g manipulation? How does category knowledge develop from 3-, t o 5-years of age? The remainder o f t h i s chapter c o n s i s t s of a g e n e r a l review of the major f i n d i n g s from the normative study and the main experiment, f o l l o w e d by a b r i e f d i s c u s s i o n of t h e i r t h e o r e t i c a l i m p l i c a t i o n s . The f i n a l s e c t i o n addresses the l i m i t a t i o n s o f my re s e a r c h and o u t l i n e s f u t u r e r e s e a r c h d i r e c t i o n s . Review of Research R e s u l t s R e s u l t s from the normative study d e s c r i b e d i n Chapter 3 gi v e i n s i g h t i n t o the p r e s c h o o l development of knowledge about category membership. The most c r i t i c a l f i n d i n g was t h a t the number of responses on category p r o d u c t i o n t e s t s i n c r e a s e d with age, with 3-year o l d s g i v i n g fewer responses than 4- and 5-year o l d s . The p r a c t i c a l i m p l i c a t i o n of t h i s f i n d i n g i s t h a t i t h i g h l i g h t s the importance o f c a r e f u l i n t e r p r e t a t i o n o f p r e s c h o o l e r s ' performance on ca t e g o r y p r o d u c t i o n t e s t s . S p e c i f i c a l l y , r e s e a r c h e r s must be aware t h a t because 4- and 5-year o l d s ' name more items than 3-year o l d s , 4- and 5-year o l d s have an i n c r e a s e d l i k e l i h o o d o f naming t a r g e t items by chance. T h i s f i n d i n g i s important t o note because i t c o u l d r e s u l t i n an e x a g g e r a t i o n of 4- and 5-year o l d s ' memory performance. One way t o a d j u s t f o r t h i s response d i f f e r e n c e i s t o s c o r e s u b j e c t s a c c o r d i n g t o the p r o p o r t i o n of t a r g e t items named out of t o t a l responses, r a t h e r than by the number of t a r g e t words named. The response d i f f e r e n c e was the only a g e - r e l a t e d d i f f e r e n c e found i n the normative study and t h i s was s u r p r i s i n g . I expected t h a t with i n c r e a s i n g age, the d i f f e r e n t age-groups might name more d i f f e r e n t items, but category d i v e r s i t y was not s i g n i f i c a n t l y d i f f e r e n t a cross the age-groups. I a l s o expected t h a t w i t h i n c r e a s i n g age s u b j e c t s might be more f a m i l i a r w i t h t y p i c a l category exemplars, r e s u l t i n g i n a l o t of s u b j e c t s naming the same items. However, t h e r e was no t y p i c a l i t y a g e - e f f e c t . While t h i s suggests t h a t t h e r e i s l i t t l e change i n c a t e g o r y knowledge, one must note t h a t although t y p i c a l i t y and d i v e r s i t y r a t i n g s d i d not d i f f e r a c r o s s the age-groups, the response r a t e s of d i f f e r e n t items d i d v a r y a c r o s s the age-groups. That i s , the t h r e e age-groups may have had very high response r a t e s f o r f i v e exemplars on a g i v e n category, but the a c t u a l items may have been d i f f e r e n t . T h i s i n d i c a t e s t h a t category knowledge across the age-groups changes more with r e s p e c t t o the frequency of p a r t i c u l a r exemplars as opposed t o the c a t e g o r y ' s response r a t e d i s t r i b u t i o n . A second i n t e r e s t i n g f i n d i n g from the normative study was the d i f f e r e n c e i n response p a t t e r n s across c a t e g o r i e s . S p e c i f i c a l l y , some c a t e g o r i e s had few items t h a t were named by a l o t of the s u b j e c t s and many items t h a t were named by o n l y a few s u b j e c t s . Other c a t e g o r i e s had many items t h a t were named 83 by most s u b j e c t s and only a s m a l l number of d i f f e r e n t items. These f i n d i n g s show t h a t category knowledge v a r i e s c o n s i d e r a b l y across d i f f e r e n t c a t e g o r i e s ; w h i l e some c a t e g o r i e s are p e r c e i v e d as b e i n g very l o o s e , w i t h no items s t a n d i n g out as being t y p i c a l exemplars, other c a t e g o r i e s are p e r c e i v e d t o have a sm a l l number of d i f f e r e n t exemplars with a few t h a t are very r e p r e s e n t a t i v e of t h a t category. These d i f f e r e n c e s h i g h l i g h t the importance of t a k i n g i n t o account category d i f f e r e n c e s when one i s u s i n g category p r o d u c t i o n t e s t s . One way t o d e a l with these d i f f e r e n c e s i s to s e l e c t o n l y those c a t e g o r i e s having s i m i l a r d i s t r i b u t i o n s . Another way i s t o separate category e f f e c t s from experimental e f f e c t s by a n a l y z i n g the data category by category. However, s i n c e more s u b j e c t s are r e q u i r e d f o r t h i s method, the former i s recommended. The experiment d e s c r i b e d i n Chapter 4 provided data on the p r e s c h o o l development of i m p l i c i t and e x p l i c i t memory. The main i m p l i c i t memory t e s t f i n d i n g s were: F i r s t , priming was s i m i l a r a c r o s s the three age-groups. Second, i m p l i c i t memory performance was a f f e c t e d by the l e v e l s of p r o c e s s i n g m a n i p u l a t i o n , w i t h more priming f o r m a t e r i a l s i n the e l a b o r a t i v e study c o n d i t i o n than those i n the n o n - e l a b o r a t i v e study c o n d i t i o n . The study a l s o r e p o r t e d three main f i n d i n g s from the e x p l i c i t memory t e s t s : F i r s t , t h e r e was a s i g n i f i c a n t a g e - r e l a t e d i n c r e a s e across the t h r e e age-groups. Second, th e r e was a main e f f e c t f o r the l e v e l of p r o c e s s i n g manipulation, w i t h higher performance i n the e l a b o r a t i v e study c o n d i t i o n than i n the n o n - e l a b o r a t i v e study c o n d i t i o n . T h i r d , there was an i n t e r a c t i o n between age and study c o n d i t i o n s . S p e c i f i c a l l y , i n the no n - e l a b o r a t i v e study c o n d i t i o n t h e r e was an a g e - r e l a t e d i n c r e a s e i n performance, w h i l e i n the e l a b o r a t i v e study c o n d i t i o n performance was s i m i l a r across the th r e e age-groups. In g e n e r a l , my f i n d i n g s are c o n s i s t e n t with the ge n e r a l i m p l i c i t / e x p l i c i t memory d i s s o c i a t i o n t h a t has been found i n the r e c e n t l i t e r a t u r e . The absence of an a g e - e f f e c t on t e s t s of i m p l i c i t memory has been found i n p r e s c h o o l e r s and s c h o o l c h i l d r e n (e.g., P a r k i n & S t r e e t e , 1988). What was d i f f e r e n t about my r e s u l t s was the l e v e l s of p r o c e s s i n g e f f e c t on i m p l i c i t memory, as d i s c u s s e d i n Chapter 4, which i s not a gen e r a l f i n d i n g (e.g., Naito, i n p r e s s ) . L e v e l s of p r o c e s s i n g e f f e c t s on i m p l i c i t memory performance have been noted, however, wi t h new a s s o c i a t i o n s i n amnesics (e.g., Graf & Schacter, 1985) and he a l t h y young a d u l t s (e.g., Graf & Schacter, 1986). The a g e - r e l a t e d i n c r e a s e i n e x p l i c i t memory performance was c o n s i s t e n t w i t h the l i t e r a t u r e on p r e s c h o o l e r s (e.g., P e r l m u t t e r & Myers, 1974) and o l d e r a d u l t s ( K a i l , 1979). However, the l a c k of an a g e - r e l a t e d i n c r e a s e f o r e l a b o r a t i v e l y s t u d i e d m a t e r i a l s , as d i s c u s s e d i n Chapter 4, i s i n c o n s i s t e n t with other s t u d i e s on young c h i l d r e n (e.g., N a i t o , i n p r e s s ) . T h i s i n c o n s i s t e n c y suggests t h a t , t o some extent, e x p l i c i t memory performance i s c o n t r o l l e d by environmental f a c t o r s . That i s , under d i f f e r e n t c o n d i t i o n s a g e - r e l a t e d i n c r e a s e s i n performance c o u l d have occurred under a l e v e l s of p r o c e s s i n g c o n d i t i o n . For example, i f my e x p l i c i t memory t e s t was more d i f f i c u l t , the l e v e l s of p r o c e s s i n g m a n i p u l a t i o n may have 85 boosted 3-year o l d s memory performance, but not t o the l e v e l of the 4- and 5-year o l d s . T h e o r e t i c a l I m p l i c a t i o n s In combination, these r e s u l t s have i m p l i c a t i o n s f o r general t h e o r i e s of i m p l i c i t and e x p l i c i t memory. What f o l l o w s i s a d i s c u s s i o n o f how these r e s u l t s f i t w ith the th r e e views memory t h a t were d i s c u s s e d i n Chapter 2; the systems, process, and a c t i v a t i o n views. A systems approach focuses on the i d e a t h a t memory i s composed of s e v e r a l d i s t i n c t systems w i t h a separate system mediating each form of memory (e.g., T u l v i n g , 1985). My r e s u l t s are c o n s i s t e n t with t h i s view and they suggest t h a t the systems mediating i m p l i c i t memory and e x p l i c i t memory f o l l o w a d i s t i n c t developmental p a t t e r n . The f i n d i n g t h a t t h e r e was no change i n i m p l i c i t memory performance a c r o s s the preschool p e r i o d suggests t h a t i t s u n d e r l y i n g system i s f u l l y i n t a c t even by the age of 3-years. Conversely, the f i n d i n g of an age-r e l a t e d i n c r e a s e i n e x p l i c i t memory performance i m p l i e s t h a t the mediating system keeps developing d u r i n g t h i s p e r i o d . How do these two systems d i f f e r ? My f i n d i n g s suggest t h a t the system mediating i m p l i c i t memory performance i s p r i m a r i l y d a t a - d r i v e n , w h i l e t h a t mediating e x p l i c i t memory performance i s p r i m a r i l y s u b j e c t - c o n t r o l l e d . The former i s probably f u l l y developed by the age of 3-years because i t i s c o n t r o l l e d by the environment and not by s u b j e c t - c o n t r o l l e d a b i l i t i e s t h a t develop w i t h i n c r e a s i n g age. S i m i l a r l y , the system mediating e x p l i c i t memory performance l i k e l y develops l a t e r because of i t s r e l i a n c e on the s u b j e c t s ' a b i l i t y t o c o n t r o l the 86 p r o c e s s i n g . A d d i t i o n a l support f o r two d i s t i n c t memory systems comes from the f i n d i n g s s u g g e s t i n g t h a t the system mediating e x p l i c i t memory t h a t i s a f f e c t e d by amnesia, whereas t h a t mediating i m p l i c i t memory i s robust to the syndrome. U n l i k e the systems views, process views focus on the mental processes t h a t are i n v o l v e d by d i f f e r e n t study tasks and t e s t s . The processes i n v o l v e d i n i m p l i c i t memory can be i n f e r r e d from i m p l i c i t memory t e s t s . Such t e s t s r e q u i r e s u b j e c t s t o say what a u t o m a t i c a l l y comes t o mind upon the p r e s e n t a t i o n of a s t i m u l u s . Processes i n v o l v e d i n e x p l i c i t memory can a l s o be i n f e r r e d from t e s t s designed t o assess t h i s form of memory. On such t e s t s , s u b j e c t s are asked t o c o n s c i o u s l y r e c a l l a p r i o r study episode and t h i s r e q u i r e s s u b j e c t s t o have c o g n i t i v e c o n t r o l over t h e i r r e t r i e v i n g a b i l i t i e s . The process view advocated by Roediger and h i s colleagues (e.g., Roediger & Blaxton, 1987) p o s t u l a t e s t h a t i m p l i c i t memory i s mediated p r i m a r i l y by mo d a l i t y s p e c i f i c , d a t a - d r i v e n processes ( i . e . , bottom-up p r o c e s s i n g ) , whereas, e x p l i c i t memory i s mediated by c o n c e p t u a l - d r i v e n p r o c e s s e s ( i . e . , top-down p r o c e s s i n g ) . By t h i s view, i t f o l l o w s from the present r e s u l t s t h a t s e n s o r y - p e r c e p t u a l , d a t a - d r i v e n processes develop p r i o r t o c o n c e p t u a l - d r i v e n processes. Furthermore, data-driven processes are l i k e l y t o develop e a r l i e r because of t h e i r r e l i a n c e on e x t e r n a l s t i m u l i as opposed t o s u b j e c t - i n i t i a t e d a b i l i t i e s , thus, the reason why i m p l i c i t memory i s f u l l y i n t a c t even i n 3-year o l d s . N e v e r t h e l e s s , while t h i s view can e x p l a i n the i m p l i c i t / e x p l i c i t memory d i s t i n c t i o n i n terms of d i f f e r e n t mediating processes, i t does not e x p l a i n how these processes a c t u a l l y f u n c t i o n . A c t i v a t i o n views are a type of process view which e x p l a i n i m p l i c i t / e x p l i c i t performance d i s s o c i a t i o n s i n terms of automatic and c o n t r o l l e d p r o c e s s i n g , r e s p e c t i v e l y ( f o r review see Graf, 1990). An a c t i v a t i o n view can e x p l a i n the f i n d i n g of a g e - r e l a t e d d i f f e r e n c e s between i m p l i c i t and e x p l i c i t memory performance, as w e l l as why they are a f f e c t e d d i f f e r e n t l y by l e v e l s of p r o c e s s i n g m a n i p u l a t i o n s . A c t i v a t i o n views assume t h a t i m p l i c i t memory i s mediated by automatic a c t i v a t i o n of p r e - e x i s t i n g r e p r e s e n t a t i o n s d u r i n g the study t r i a l . By such a view, I d i d not expect a l e v e l s of p r o c e s s i n g e f f e c t on i m p l i c i t memory performance. However, as d i s c u s s e d i n Chapter 4 , a l e v e l s e f f e c t can occur with u n f a m i l i a r m a t e r i a l s . Because of the n o v e l t y of some (or a l l ) items i n the present study, they may have been learned l i k e new items. R e l a t e d previous work by Graf and Schacter (1987) has shown t h a t when presented w i t h u n f a m i l i a r m a t e r i a l s — u n r e l a t e d word p a i r s — s u b j e c t s showed an i m p l i c i t memory e f f e c t o n l y with study t a s k s t h a t r e q u i r e d e l a b o r a t i v e p r o c e s s i n g of the p a i r e d words. T h i s f i n d i n g suggests t h a t i m p l i c i t memory depends on more than mere a c t i v a t i o n . For m a t e r i a l s t h a t have no p r e -e x i s t i n g r e p r e s e n t a t i o n t h a t can be a c t i v a t e d d u r i n g the study t r i a l , some form of e l a b o r a t i v e p r o c e s s i n g i s r e q u i r e d t o e s t a b l i s h a memory r e p r e s e n t a t i o n ( c . f . , Graf & Schacter, 1987). The r e s u l t s from my study a l s o suggest t h a t priming was not mediated e n t i r e l y by automatic p r o c e s s i n g , but some form of e l a b o r a t i v e study p r o c e s s i n g was r e q u i r e d t o achieve the maximum priming e f f e c t , and most important, t h a t even 3-year o l d s were able t o engage i n t h i s type of p r o c e s s i n g . Furthermore, because once the r e p r e s e n t a t i o n has been e s t a b l i s h e d f u r t h e r e l a b o r a t i o n has no e f f e c t on i m p l i c i t memory performance, t h i s view a l s o supports the theory t h a t i m p l i c i t memory i s p r i m a r i l y mediated by automatic processes. E x p l i c i t memory r e s u l t s are a l s o e x p l a i n e d by a c t i v a t i o n views. A c t i v a t i o n views assume t h a t e l a b o r a t i v e p r o c e s s i n g r e l a t e s a t a r g e t item with o t h e r items, s i t u a t i o n a l cues, and p r i o r knowledge. The e f f e c t of such p r o c e s s i n g i s t h a t i t c r e a t e s a d d i t i o n a l paths t o the r e p r e s e n t a t i o n and, t h e r e f o r e , i n c r e a s e s the l i k e l i h o o d of an item being e x p l i c i t l y r e c a l l e d . T h i s means t h a t , i f 3-year o l d s are unable t o c a r r y out e l a b o r a t i v e p r o c e s s i n g , they w i l l have fewer paths t o the r e p r e s e n t a t i o n and, as a r e s u l t , not r e c a l l as many items as o l d e r c h i l d r e n . Since the study t a s k i n the present study guided the e l a b o r a t i v e p r o c e s s i n g of items, the 3-year o l d s were enabled t o process the m a t e r i a l s e l a b o r a t i v e l y and, t h e r e f o r e , perform as w e l l as 4- and 5-year o l d s on t e s t s of e x p l i c i t memory. In summary, my r e s u l t s , i n combination w i t h t h i s t h e o r e t i c a l p e r s p e c t i v e , suggest t h a t i m p l i c i t memory i s not mediated e n t i r e l y by automatic processes, but a l s o by c o n t r o l l e d processes. When m a t e r i a l s are new, e l a b o r a t i v e p r o c e s s i n g i s necessary t o e s t a b l i s h a r e p r e s e n t a t i o n which may then be a u t o m a t i c a l l y a c t i v a t e d when some of i t s components are presented. 89 L i m i t a t i o n s of the Present Experiment and Future Research I n t e r p r e t a t i o n and g e n e r a l i z a t i o n of the f i n d i n g s from t h i s work i s c o n s t r a i n e d by s e v e r a l f a c t o r s . These w i l l have t o be addressed by f u t u r e r e s e a r c h . The most c r i t i c a l l i m i t a t i o n of my f i n d i n g s comes from the f a c t t h a t o n l y one t e s t — c a t e g o r y c u e d - r e c a l l and category p r o d u c t i o n was used t o assess each form of memory performance. Prev i o u s work has shown d i f f e r e n c e s i n performance a c r o s s d i f f e r e n t t e s t s of e i t h e r form of memory. For example, when a study c o n s i s t s of study phases i n one modality and t e s t phases i n another m o d a l i t y , e x p l i c i t memory performance i s s i m i l a r i n w i t h i n - and between- modality c o n d i t i o n s while i m p l i c i t memory performance i s h i g h e r i n w i t h i n - m o d a l i t y c o n d i t i o n s than i n between-modality c o n d i t i o n s (e.g., Graf, Shimamura, & Squire, 1985). Because of t h i s , the i m p l i c a t i o n s drawn from my study must be taken w i t h c a u t i o n u n t i l s i m i l a r s t u d i e s u s i n g d i f f e r e n t memory t e s t s have been c a r r i e d out. A second aspect of my study t h a t l i m i t s i n t e r p r e t a t i o n of the r e s u l t s comes from the procedure used t o s e l e c t the m a t e r i a l s . In order to make meaningful comparison across the d i f f e r e n t age-groups, I s e l e c t e d m a t e r i a l s t h a t would y i e l d s i m i l a r performance r a t e s f o r 3-, 4- and 5-year o l d s . T h i s s e l e c t i o n of m a t e r i a l s may have reduced (or el i m i n a t e d ) the p o s s i b i l i t y o f f i n d i n g a g e - r e l a t e d d i f f e r e n c e s i n b a s e l i n e performance and, thus, need t o be examined f u r t h e r i n f u t u r e r e s e a r c h . The t h i r d l i m i t a t i o n of the main experiment i s t h a t i t only i n v o l v e d a s m a l l age-range of s u b j e c t s . T h i s i s l i m i t i n g because one cannot i n f e r the developmental p a t t e r n of memory from o n l y a l i m i t e d age-range. In order t o get a broader view of i m p l i c i t memory development, a s i m i l a r study with a wider range of s u b j e c t s i s necessary. The f o u r t h l i m i t a t i o n of the main experiment i s the s m a l l number of s u b j e c t s . Because of these s m a l l n's, males and females c o u l d not balanced p e r f e c t l y a c r o s s the c e l l s . While no gender d i f f e r e n c e s were apparent, a study w i t h a w e l l -balanced d e s i g n w i t h r e s p e c t t o gender should be c a r r i e d out t o r a i s e the l e v e l of confidence t h a t t h e r e are no gender d i f f e r e n c e s d u r i n g t h i s age. The s m a l l number of s u b j e c t s a l s o prevented the i n c l u s i o n of an order of t e s t i n g c o n d i t i o n . For both the category p r o d u c t i o n t e s t s and category c u e d - r e c a l l t e s t s , c a t e g o r i e s i n the e l a b o r a t i v e study c o n d i t i o n were always t e s t e d f i r s t and those i n the n o n - e l a b o r a t i v e c o n d i t i o n were t e s t e d second. While t h i s should not be a problem because of the small time-d e l a y between study and t e s t i n g , the p o s s i b i l i t y of an order e f f e c t e x i s t s . Future r e s e a r c h should i n c l u d e c o u n t e r b a l a n c i n g d i f f e r e n t memory t e s t s and modality m a n i p u l a t i o n s . Experiments w i t h d i f f e r e n t t e s t s , as d i s c u s s e d i n the f i r s t l i m i t a t i o n o f my study, should be c a r r i e d out because of the v a r i a b i l i t y i n r e s u l t s . S t u d i e s with only one or two i m p l i c i t and e x p l i c i t memory t e s t s are l i m i t e d i n terms of g e n e r a l i z a b i l i t y t o oth e r t e s t s . I t would a l s o be i n t e r e s t i n g t o c a r r y out an experiment s i m i l a r t o t h a t i n Chapter 4, but wit h a modality m a n i p u l a t i o n . Because i t has g e n e r a l l y been found t h a t i m p l i c i t memory performance i s h i g h e r i n w i t h i n - m o d a l i t y c o n d i t i o n s as opposed t o between-modality c o n d i t i o n s (e.g., K i r s n e r , M i l e c h , & Standen, 1983) i t would be i n t e r e s t i n g t o see what the e f f e c t s of m odality are d u r i n g the preschool age. Conc l u s i o n T h i s t h e s i s examined category knowledge and i m p l i c i t and e x p l i c i t memory development d u r i n g the p r e s c h o o l y e a r s . Important f i n d i n g s were r e v e a l e d from both the category p r o d u c t i o n normative study i n Chapter 3, and the memory development study i n Chapter 4. Three important p o i n t s of i n f o r m a t i o n r e s u l t e d from the present r e s e a r c h . F i r s t , the f i n d i n g of d i f f e r e n c e s i n category knowledge h i g h l i g h t the need f o r c o n t r o l l i n g f a m i l i a r i t y w i t h items a c r o s s s u b j e c t groups. Second, the a n a l y s i s o f responses showed how d i f f e r e n t indexes provide u s e f u l d e s c r i p t o r s o f s u b j e c t s ' knowledge of c a t e g o r i e s . T h i r d , the normative data study and main experiment showed an e f f e c t i v e method f o r t e s t i n g i m p l i c i t memory performance i n young c h i l d r e n . Most i m p l i c i t memory t e s t s are e i t h e r too a b s t r a c t f o r 3-year o l d s t o comprehend or r e q u i r e r e a d i n g and, t h e r e f o r e , cannot be performed by most p r e s c h o o l e r s . My method i n v o l v e d r e a d i n g the c h i l d r e n a s t o r y r e l a t e d t o s p e c i f i c c a t e g o r i e s b e f o r e a s k i n g them t o name items. 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I n f a n t s , amnesics, and d i s s o c i a b l e memory systems. In M. Moscovitch (Ed.), I n f a n t memory: I t s r e l a t i o n t o normal and p a t h o l o g i c a l  memory i n humans and other animals (pp. 173-216). New York: Plenum. Schneider, W. & S h i f f r i n , R.M. (1977). C o n t r o l l e d and automatic i n f o r m a t i o n p r o c e s s i n g . I. D e t e c t i o n , search, and a t t e n t i o n . P s y c h o l o g i c a l Review, 84, 1-66. S h i f f r i n , R.M. & Schneider, W. (1977). C o n t r o l l e d and automatic human in f o r m a t i o n p r o c e s s i n g : I I . Pe r c e p t u a l l e a r n i n g , automatic a t t e n d i n g , and a general theory. P s y c h o l o g i c a l Review, 84, 127-190. Shimamura, A.P., & Squire, L.R. (1984). P a i r e d - a s s o c i a t e l e a r n i n g and priming e f f e c t s i n amnesia: A n e u r o p s y c h o l o g i c a l study. J o u r n a l of Experimental  Psychology: General, 113, 556-570. Sq u i r e , L.R., & Cohen, N.J. (1984). Human memory and amnesia. In J . McGaugh, G. Lynch, & N. Weinberger (Eds.), Proceedings o f the conference on the neurobiology of  l e a r n i n g and memory. New York: G u i l f o r d P r e s s . T u l v i n g , E. (1985). How many memory systems are there? American P s y c h o l o g i s t , 40.(4), 385-398. 96 APPENDIX A Category S t o r i e s and Questions Toys S t o r y : One day a l i t t l e b o y / g i r l named Lee won a t r i p t o the b i g g e s t t o y s t o r e i n the whole world. When Lee got to the s t o r e he/she saw hundreds of rows of t o y s . Questions: 1) What k i n d o f toys do you t h i n k Lee saw i n the toy s t o r e ? 2) I f you went t o the toy s t o r e , what would you buy? 3) What k i n d of toys would you buy f o r your f r i e n d s ? 4) Do you have some f a v o r i t e toys t h a t you l i k e to p l a y with? Zoo S t o r y : One day a l i t t l e b o y / g i r l named Kerry went t o the zoo f o r the v e r y f i r s t time. He/she walked up t o these very b i g gates which s a i d zoo on them. Kerry walked through the gates and i n s i d e he/she saw hundreds of animals. Q u e s t i o n s : 1) Can you t e l l me what animals Kerry they saw i n the zoo? 2) Can you t h i n k of some animals Kerry might see i n some of the cages a t the zoo? 3) When you went t o the zoo what k i n d of animals d i d you see? T r a v e l S t o r y : There was l i t t l e b o y / g i r l named K e l l y and her parents t r a v e l l e d a l o t i n t h e i r town and a l l over the world. U s u a l l y i t was t o v i s i t r e l a t i v e s (aunts, u n c l e s , grandma, grandpa). They used d i f f e r e n t t h i n g s t o r i d e on t o get p l a c e s because sometimes they d i d n ' t have to go f a r , and sometimes they had to go very f a r . Questions: 1) What can K e l l y ' s Mom and Dad might r i d e on to v i s i t t h e i r d i f f e r e n t r e l a t i v e s ? 2) What would they r i d e on t o get there? 3) I t s way t o o f a r t o walk so what c o u l d they r i d e i n so they wouldn't have t o walk? 97 Restaurant S t o r y : Pat i s ve r y happy today. H i s / h e r Mom and Dad decided to take Pat t o a r e s t a u r a n t f o r dinner because he's/she's been such a good b o y / g i r l . So o f f they went t o the r e s t a u r a n t . Questions: 1) When they got i n s i d e the r e s t a u r a n t i t was very b i g so Pat saw l o t s of t h i n g s i n s i d e of the r e s t a u r a n t . What do you t h i n k Pat saw i n the r e s t a u r a n t ? 2) What do you t h i n k Pat saw i n the r e s t a u r a n t t h a t was not food? Something people don't e a t . 3) I f I gave you a d o l l house t h a t had a r e s t a u r a n t i n i t , what would you put i n s i d e o f the r e s t a u r a n t so t h a t i t looked l i k e a r e s t a u r a n t ? 4) What do you see i n when you go to a r e s t a u r a n t ? K i t c h e n S t o r y : E r i n i s a l i t t l e b o y / g i r l t h a t j u s t l o v e s going to grandma's house because E r i n ' s grandma always l e t s him/her help her i n the k i t c h e n when making di n n e r . So when E r i n gets to grandma's house the f i r s t t h i n g he/she does i s race t o the k i t c h e n t o h e l p grandma. Questions: 1) What k i n d o f k i t c h e n t h i n g s do you t h i n k E r i n sees when he goes i n the kitchen? 2) What k i t c h e n t h i n g s do l o t s o f people have i n t h e i r k i t c h e n s ? 3) Your k i t c h e n i s n ' t an empty room i s i t ? What k i t c h e n t h i n g s do you see i n your k i t c h e n a t home? Playground Sto r y : One day a l i t t l e b o y / g i r l named C h r i s met another l i t t l e b o y / g i r l named Dale. Dale was sad because he/she d i d n ' t have anyone t o p l a y with. To make Dale happy, C h r i s decided t o take him/her t o the playground t o have fun. Dale was very happy when they got there because t h e r e were so many t h i n g s to p l a y w i t h and see a t the playground. Questions: 1) What do you t h i n k Dale saw a t the playground? 2) What do you see when you go t o the playground? 3) Are t h e r e d i f f e r e n t t h i n g s you can see a t the playground? L i k e what? 98 C l o t h e s S t o r y : One day, a l i t t l e b o y / g i r l named J e s s i e was h e l p i n g h i s / h e r parents hang c l o t h e s on the c l o t h e s l i n e t o dry. Then suddenly, a b i g wind came up and blew them a l l away. T h i s meant t h a t J e s s i e and h i s / h e r parents had t o go and buy a l l new c l o t h e s or they would have nothing t o wear on t h e i r b o d i e s . They went t o the b i g g e s t c l o t h i n g s t o r e i n town and saw l o t s and l o t s of c l o t h e s . Questions: 1) What k i n d of c l o t h e s can J e s s i e ' s parents buy so they a l l have c l o t h e s t o wear on t h e i r bodies? 2) What are t h i n g s t h a t people wear on t h e i r bodies? 3) When people get dressed i n the morning what do they put on t h e i r bodies? 4) What k i n d o f c l o t h e s ? Can you t h i n k o f the names of some c l o t h e s people wear? 99 APPENDIX B A n a l y s i s of Variance Tables One-way ANOVAs f o r Table 2 Mean Number of Responses per Category. Sums of Means Source Squares df Squares F-Ratio P Age 2.901 2 1.451 29.706 >.001 E r r o r .879 18 .049 Category .429 6 .071 . 298 .928 E r r o r 3.352 14 .239 One-way ANOVAs f o r Table 3 Mean Number of D i f f e r e n t Responses per Category. Source Sums of Squares df Means Squares F-Ratio P Category E r r o r 7.701 .155 6 14 1.283 .011 115.726 >.001 Age E r r o r .003 7.853 2 18 .002 .436 .004 .996 One-wav ANOVAs f o r Table 6 Category T v o i c a l i t v Ratings (Index of Commonality-IC) Source Sums of Squares df Means Squares F-Ratio P Category E r r o r .468 .086 6 14 .078 .006 12.755 >. 001 Age E r r o r .063 .491 2 18 .032 .027 1.156 .337 100 One-way ANOVAs f o r Table 8 Category D i v e r s i t y Ratings (Type/Token Ratios-TTR) Sums of Means Source Squares df Squares F-Ratio P Category .434 6 .072 38.388 >.001 E r r o r .026 14 .002 Age .020 2 .010 .409 .671 E r r o r .440 18 .024 One-way ANOVAs f o r Table 10  T y p i c a l i t y / D i v e r s i t y R a t i o s fTDR) Sums of Means Source Squares df Squares F-Ratio P Category 19.396 6 3.233 9.508 >.001 E r r o r 4.760 14 .340 Age 2.641 2 1.321 1.105 .353 E r r o r 21.514 18 1.195 101 APPENDIX C L i s t 1: A l p h a b e t i c a l Ordered Category Production Norms SUBJECT AGE-GROUP THREE YEARS FOUR YEARS FIVE YEARS TOTAL SAMPLE ITEM f % f % f % f % CATEGORY: CLOTHES BARRETTE 1 3, .33 0 0. ,00 0 0, .00 1 1. .11 BATHSUIT 2 6, .67 0 0, .00 0 0, .00 2 2, .22 BLOUSE 0 0. .00 0 0. .00 1 3 . 57 1 1. .11 BOOTS 0 0. .00 1 3, .23 1 3. .57 2 2. .22 BRA 1 3. .33 0 0. .00 0 0. .00 1 1. ,11 COAT 2 6, .67 1 3, . 23 0 0, .00 3 3, .33 CUTOFFS 0 0, .00 0 0. ,00 1 3. .57 1 1. ,11 DRESS 10 33. .33 15 48, .39 9 32, .14 34 37, .78 DRESSHIRT 0 0. ,00 0 0. ,00 1 3. .57 1 1. .11 DRESSPANT 0 0, .00 0 0, .00 1 3, .57 1 1, .11 EARRINGS 0 0. ,00 2 6. .45 0 0. .00 2 2. ,22 EXERCPANT 1 3, .33 0 0, .00 0 0, .00 1 1. .11 HAT 3 10. .00 4 12. .90 4 14. .29 11 12. .22 JACKET 3 10, .00 2 6, .45 2 7, .14 7 7, .78 JAMMIES 2 6. ,67 0 0. .00 0 0. .00 2 2. , 22 JEANS 0 0, .00 3 9, .68 4 14, .29 7 7, .78 JOGPANTS 1 3 . ,33 0 0. ,00 0 0. ,00 1 1. ,11 JOGSHIRT 1 3, .33 0 0, .00 0 0, .00 1 1, .11 JOGSHORT 1 3. .33 0 0. ,00 0 0. .00 1 1. ,11 JUMPER 0 0, .00 1 3, .23 0 0, .00 1 1, .11 LEGWARM 0 0. .00 1 3. ,23 0 0. .00 1 1. .11 LEOTARD 0 0. .00 1 3, .23 0 0, .00 1 1, .11 LNGSLVDSHT 1 3 . 33 0 0. ,00 0 0. ,00 1 1. .11 MITTS 0 0. .00 0 0, .00 1 3, .57 1 1, .11 NECKLACE 0 0. ,00 1 3. ,23 0 0. .00 1 1. .11 PAJAMAS 0 0. .00 3 9, .68 0 0, .00 3 3. . 33 PANTIES 1 3. ,33 3 9. ,68 3 10. ,71 7 7. ,78 PANTS 21 70. .00 30 96. .77 23 82. .14 74 82. .22 RAINCOAT 1 3 . 33 0 0. ,00 0 0. .00 1 1. ,11 RINGS 0 0. .00 1 3. .23 0 0. .00 1 1. .11 SCARVES 0 0. ,00 0 0. ,00 1 3. ,57 1 1. ,11 SHIRT 14 46, .67 24 77, .42 20 71. .43 58 64. .44 SHOES 9 30. .00 10 32. , 26 8 28. ,57 27 30. ,00 SHORTS 8 26, .67 11 35, .48 9 32, .14 28 31. .11 SHRTSLVDSHT 2 6. ,67 0 0. ,00 3 10. ,71 5 5. ,56 SKIRT 2 6. .67 4 12, .90 4 14, .29 10 11. .11 SLIPPERS 0 0. .00 0 0. ,00 1 3 . ,57 1 1. ,11 SNOWPANT 0 0. .00 2 6. .45 0 0. .00 2 2. , 22 SOCKS 10 33 . ,33 14 45. ,16 17 60. ,71 41 45. ,56 STOCKING 1 3. ,33 0 0. .00 1 3. ,57 2 2. .22 102 SUBJECT AGE-GROUP THREE YEARS FOUR YEARS FIVE YEARS TOTAL SAMPLE ITEM f % f % f % f % SUIT 1 3.33 0 0.00 0 0.00 1 1.11 SUSPENDER 0 0.00 0 0.00 2 7.14 2 2.22 SWEATER 6 20.00 5 16.13 2 7.14 13 14.44 SWIMSUIT 2 6.67 0 0.00 0 0.00 2 2.22 SWTSHRT 2 6.67 0 0.00 2 7.14 4 4.44 TIGHTS 0 0.00 1 3.23 0 0.00 1 1.11 TOWEL 1 3.33 0 0.00 0 0.00 1 1.11 TROUSERS 0 0.00 1 3.23 1 3.57 2 2.22 TSHIRT 7 23.33 7 22.58 4 14.29 18 20.00 TURTNECK 0 0.00 0 0.00 1 3.57 1 1.11 UNDERPANTS 0 0.00 0 0.00 1 3.57 1 1.11 UNDERSHRT 2 6.67 0 0.00 4 14.29 6 6.67 UNDERWEAR 4 13.33 7 22.58 5 17.86 16 17.78 UNDIES 1 3.33 1 3.23 0 0.00 2 2. 22 VESTS 0 0.00 1 3.23 0 0.00 1 1.11 CATEGORY: KITCHEN APPLEJUICE 1 3.33 0 0.00 0 0.00 1 1.12 APRON 1 3.33 0 0.00 0 0.00 1 1.12 BEATERS 0 0.00 0 0.00 1 3.57 1 1.12 BOOKS 0 0.00 0 0.00 1 3.57 1 1.12 BOWL 3 10.00 0 0.00 5 17.86 8 8.99 BOXES 0 0.00 1 3.23 0 0.00 1 1.12 BREAD 1 3.33 0 0.00 0 0.00 1 1.12 BR00MCL0SET 0 0.00 0 0.00 1 3.57 1 1.12 CANDIES 2 6.67 1 3.23 0 0.00 3 3.37 CHAIR 4 13.33 8 25.81 4 14.29 16 17.98 CHICKENSOUP 1 3.33 0 0.00 0 0.00 1 1.12 CONTAINERS 0 0.00 1 3.23 0 0.00 1 1.12 COOKIES 1 3.33 2 6.45 1 3.57 4 4.49 COOKGLOVES 0 0.00 1 3.23 0 0.00 1 1.12 COUNTER 1 3.33 7 22.58 2 7.14 10 11.24 CUPBOARDS 4 13.33 8 25.81 5 17.86 17 19.10 CUPS 5 16.67 2 6.45 8 28.57 15 16.85 DADS 1 3.33 0 0.00 0 0.00 1 1.12 DISHES 4 13.33 4 12.90 0 0.00 8 8.99 DISHWASHER 1 3.33 1 3.23 0 0.00 2 2.25 DOORS 1 3.33 1 3.23 0 0.00 2 2.25 DRAWERS 0 0.00 3 9.68 1 3.57 4 4.49 DRINK 1 3.33 0 0.00 0 0.00 1 1.12 EGGS 0 0.00 1 3.23 0 0.00 1 1.12 ELECTCANOPEN 0 0.00 0 0.00 1 3.57 1 1.12 FLOOR 2 6.67 2 6.45 0 0.00 4 4.49 FOOD 10 33.33 2 6.45 4 14.29 16 17.98 103 SUBJECT AGE-GROUP THREE YEARS FOUR YEARS FIVE YEARS TOTAL SAMPLE ITEM f % f % f % f F00DC0L0R 0 0. .00 0 0 .00 1 3. .57 1 1. .12 FORKS 7 23. .33 7 22 .58 12 42, .86 26 29, .21 FREEZER 2 6. .67 1 3 .23 0 0. .00 3 3. .37 FRIDGE 9 30. .00 12 38 .71 4 14, .29 25 28, .09 FRUIT 0 0. ,00 1 3 .23 0 0. .00 1 1, .12 FRUITROLLUP 1 3. .33 0 0 .00 0 0. .00 1 1, .12 GARBAGE 0 0. ,00 1 3 .23 0 0. .00 1 1, .12 GLASS 0 0. .00 1 3 .23 1 3, .57 2 2, .25 JARS 0 0. ,00 0 0 .00 1 3 . 57 1 1. .12 JUICE 0 0. .00 1 3 . 23 0 0, .00 1 1, .12 KETTLES 0 0. ,00 0 0 .00 1 3. .57 1 1. .12 KNIFESHARP 0 0. .00 0 0 .00 1 3. .57 1 1, .12 KNIVES 6 20. ,00 5 16 .13 9 32. ,14 20 22. .47 LIGHTS 0 0. .00 0 0 .00 3 10, .71 3 3, .37 MICROWAVES 0 0. ,00 0 0 .00 2 7. ,14 2 2. ,25 MILK 4 13. .33 1 3 .23 0 0, .00 5 5. .62 MOMMIES 1 3 . 33 0 0 .00 0 0. ,00 1 1. .12 MUG 0 0. .00 0 0 .00 1 3, .57 1 1, .12 NOODLES 1 3. .33 0 0 .00 0 0. ,00 1 1. .12 OVENS 1 3. . 33 4 12 .90 3 10, .71 8 8. .99 PANS 2 6. .67 8 25 .81 4 14. ,29 14 15. ,73 PAPER 1 3. . 33 0 0 .00 0 0, .00 1 1. .12 PEOPLE 1 3 . 33 0 0 .00 0 0. ,00 1 1. ,12 PLASTICKNIVE 0 0. .00 1 3 .23 0 0. .00 1 1. .12 PLATES 7 23 . 33 3 9 .68 8 28. ,57 18 20. ,22 POP 1 3. .33 0 0 .00 0 0, .00 1 1, .12 POTS 1 3. .33 9 29 .03 6 21. ,43 16 17. ,98 RADIO 0 0. .00 0 0 .00 1 3. .57 1 1. .12 RICEKRISPI 1 3. .33 0 0 .00 0 0. ,00 1 1. .12 SANDWHICH 1 3. .33 0 0 .00 0 0, .00 1 1. .12 SHARPKNIVE 0 0. .00 1 3 .23 0 0. .00 1 1. ,12 SINK 6 20. .00 10 32 .26 5 17, .86 21 23. .60 SKELTCROSSB 0 0. .00 0 0 .00 1 3. ,57 1 1. ,12 SPAGHETTI 0 0. .00 1 3 . 23 0 0, .00 1 1. .12 SPATULA 0 0. .00 0 0 .00 1 3. .57 1 1. ,12 SPONGES 0 0. .00 1 3 .23 0 0, .00 1 1. . 12 SPOONS 6 20. .00 7 22 .58 12 42. ,86 25 28. ,09 STOOLS 1 3. . 33 0 0 .00 0 0, .00 1 1. .12 STOVES 12 40. .00 15 48 .39 8 28. ,57 35 39. ,33 SUGAR 0 0. . 00 0 0 .00 1 3. .57 1 1. .12 TABLE 7 23. .33 13 41 .94 8 28. ,57 28 31. ,46 TAPS 0 0. .00 0 0 .00 1 3. .57 1 1. , 12 TEACUPS 0 0. .00 1 3 .23 0 0. ,00 1 1. ,12 TEAKETTLE 1 3. ,33 1 3 .23 0 0. ,00 2 2. ,25 TOAST 0 0. .00 1 3 .23 0 0. ,00 1 1. ,12 TOASTER 1 3. , 33 0 0 .00 1 3. ,57 2 2. ,25 104 SUBJECT AGE-GROUP THREE YEARS FOUR YEARS FIVE YEARS TOTAL SAMPLE ITEM f % f % f % f % TV 1 3.33 0 0.00 0 0.00 1 1.12 WATER 1 3.33 1 3.23 0 0.00 2 2.25 WATERMELON 0 0.00 0 0.00 1 3.57 1 1.12 WINDOWS 0 0.00 1 3.23 2 7.14 3 3.37 T^EGORY: PLAYGROUND ANIMALS 0 0.00 1 3.13 0 0.00 1 1.10 ANT 1 3.23 0 0.00 0 0.00 1 1.10 BALL 0 0.00 0 0.00 1 3.57 1 1.10 BALLOONS 0 0.00 1 3.13 0 0.00 1 1.10 BARS 1 3.23 0 0.00 1 3.57 2 2.20 BEACH 1 3.23 1 3.13 0 0.00 2 2.20 BIKES 0 0.00 1 3.13 1 3.57 2 2.20 BIRDS 0 o.oo- 4 12.50 0 0.00 4 4.40 BLOCKS 1 3.23 0 0.00 0 0.00 1 1.10 BLUESKY 0 0.00 1 3.13 0 0.00 1 1.10 BOAT 1 3.23 1 3.13 0 0.00 2 2.20 BOYS 1 3.23 0 0.00 0 0.00 1 1.10 BRIDGES 2 6.45 3 9.38 2 7.14 7 7.69 BUG 2 6.45 0 0.00 0 0.00 2 2.20 BUNNIES 0 0.00 1 3.13 0 0.00 1 1.10 BUTTERFLY 1 3.23 0 0.00 0 0.00 1 1.10 CARS 0 0.00 1 3.13 0 0.00 1 1.10 CATS 1 3.23 1 3.13 0 0.00 2 2.20 CHILDREN 1 3.23 1 3.13 0 0.00 2 2.20 CHURCH 1 3.23 0 0.00 0 0.00 1 1.10 CLIMBER 5 16.13 9 28.13 11 39.29 25 27.47 CLOUDS 1 3.23 0 0.00 0 0.00 1 1.10 COCACOLA 1 3.23 0 0.00 0 0.00 1 1.10 CONCRETE 0 0.00 0 0.00 1 3.57 1 1.10 CUPS 0 0.00 0 0.00 1 3.57 1 1.10 DIGGERS 0 0.00 0 0.00 1 3.57 1 1.10 DINOSAUR 1 3.23 0 0.00 0 0.00 1 1.10 DOGS 2 6.45 1 3.13 1 3.57 4 4.40 DUCKS 0 0.00 0 0.00 1 3.57 1 1.10 ELEPHANTS 1 3.23 1 3.13 0 0.00 2 2.20 FISH 1 3.23 0 0.00 0 0.00 1 1.10 FLOWERS 0 0.00 1 3.13 1 3.57 2 2.20 FOOTBALL 1 3 .23 0 0.00 0 0.00 1 1.10 FRIEND 0 0.00 0 0.00 1 3.57 1 1.10 GATE 0 0.00 0 0.00 1 3 .57 1 1.10 GEESE 0 0.00 0 0.00 1 3.57 1 1.10 GIRLS 1 3 .23 0 0.00 0 0.00 1 1.10 GRASS 0 0.00 1 3.13 1 3.57 2 2.20 105 SUBJECT AGE-GROUP THREE YEARS FOUR YEARS FIVE YEARS TOTAL SAMPLE ITEM f % f % f % f % HANGERS 0 0.00 1 3.13 1 3.57 2 2.20 HIGHTOPS 0 0.00 0 0.00 1 3.57 1 1.10 HILLS 0 0.00 1 3 .13 1 3.57 2 2.20 TIREHOLES 0 0.00 1 3.13 0 0.00 1 1.10 HOPSCOTCH 1 3.23 0 0.00 0 0.00 1 1.10 HOUSES 2 6.45 2 6.25 0 0.00 4 4.40 JUNGLEGYM 1 3.23 2 6.25 0 0.00 3 3.30 KIDS 1 3.23 1 3.13 0 0.00 2 2.20 LAPDER 2 6.45 3 9.38 3 10.71 8 8.79 LEAVES 1 3.23 1 3.13 0 0.00 2 2.20 LITTLEHOUSE 0 0.00 1 3.13 0 0.00 1 1.10 MERRYGOROUND 1 3.23 5 15.63 2 7.14 8 8.79 MONKEYBARS 2 6.45 1 3.13 4 14.29 7 7.69 PEACOCKS 1 3.23 0 0.00 0 0.00 1 1.10 PEOPLE 4 12.90 1 3 .13 1 3 .57 6 6.59 PICNICTABLE 0 0. 00 1 3.13 0 0.00 1 1.10 PLANTS 0 0.00 0 0.00 1 3.57 1 1.10 PLAYHOUSE 2 6.45 1 3.13 1 3.57 4 4.40 PLAYSEABUS 0 0.00 0 0.00 1 3.57 1 1.10 POLE 4 12.90 1. 3.13 9 32.14 14 15.38 POND 2 6.45 0 0.00 2 7.14 4 4.40 RAKES 0 0.00 0 0.00 1 3.57 1 1.10 RAMP 0 0.00 0 0.00 1 3.57 1 1.10 RING 0 0.00 0 0.00 1 3.57 1 1.10 RIVER 0 0.00 0 0.00 1 3.57 1 1.10 ROPES 0 0.00 1 3.13 2 7.14 3 3.30 ROUNDABOUT 0 0.00 1 3.13 2 7.14 3 3.30 RUNNING 0 0.00 1 3.13 0 0.00 1 1.10 SAND 2 6.45 3 9.38 1 3.57 6 6 .59 SANDBOX 1 3.23 2 6.25 3 10.71 6 6.59 SANDWHICHES 0 0.00 1 3.13 0 0.00 1 1.10 SCHOOL 0 0.00 2 6.25 0 0.00 2 2.20 SEE-SAW 1 3.23 1 3.13 0 0.00 2 2.20 SHOVEL 0 0.00 0 0.00 1 3.57 1 1.10 SKATEBOARDS 1 3.23 0 0.00 0 0.00 1 1.10 SLIDES 25 80.65 27 84. 38 24 85.71 76 83. 52 SNAILS 1 3.23 0 0.00 0 0.00 1 1.10 SNAKE 1 3.23 0 0.00 0 0.00 1 1.10 SOCCERTEAM 1 3.23 0 0.00 0 0.00 1 1.10 SPRINKLER 0 0.00 0 0.00 1 3.57 1 1.10 STAIRS 2 6.45 3 9. 38 1 3.57 6 6.59 STEERWHEEL 1 3.23 0 0.00 0 0.00 1 1.10 SWIMPOOL 1 3.23 2 6.25 0 0.00 3 3.30 SWINGS 20 64.52 29 90.63 22 78.57 71 78.02 TABLE 0 0.00 1 3.13 0 0.00 1 1.10 TEETTOTTER 5 16.13 9 28.17 4 14.29 18 19.80 106 SUBJECT AGE-GROUP THREE YEARS FOUR YEARS FIVE YEARS TOTAL SAMPLE ITEM f % f % f % f TIRES 1 3.23 3 9.38 2 7.14 6 6.59 TIRESWING 4 12.90 3 9.38 6 21.43 13 14.29 TOWER 1 3.23 0 0.00 0 0.00 1 1.10 TOYS 1 3.23 1 3.13 0 0.00 2 2.20 TREEHOUSE 2 6.45 1 3.13 0 0.00 3 3.30 TREES 0 0.00 3 9.38 1 3.57 4 4.40 TRICYCLES 0 0.00 0 0.00 1 3.57 1 1.10 TUNNEL 1 3.23 1 3.13 0 0.00 2 2.20 WATER 1 3.23 1 3.13 0 0.00 2 2.20 WATERFOUNT 0 0.00 1 3.13 0 0.00 1 1.10 WORM 1 3.23 0 0.00 0 0.00 1 1.10 CATEGORY: RESTAURANT APPLEJUICE 0 0.00 0 0.00 1 3.70 1 1.14 BAKERMEN 0 0.00 0 0.00 1 3.70 1 1.14 BAKER 0 0.00 2 6.25 0 0.00 2 2.27 BALLOON 1 3.45 1 3.13 0 0.00 2 2.27 BATHROOM 2 6.90 1 3.13 1 3.70 4 4.55 BOOKS 1 3.45 0 0.00 0 0.00 1 1.14 BOOTH 0 0.00 0 0.00 1 3.70 1 1.14 BOOTS 1 3.45 0 0.00 0 0.00 1 1.14 BOWLS 1 3 .45 1 3.13 2 7.41 4 4.55 BOX 0 0.00 0 0.00 1 3.70 1 1.14 BUNNIES 0 0.00 1 3.13 0 0.00 1 1.14 CAKE 1 3.45 0 0.00 2 7.41 3 3.41 CANDY 3 10.34 0 0.00 1 3.70 4 4.55 CARPET 0 0.00 1 3.13 0 0.00 1 1.14 CAT 0 0.00 0 0.00 1 3.70 1 1.14 CHAIRS 7 24.14 18 56.25 13 48.15 38 43.18 CHEF 2 6.90 0 0.00 2 7.41 4 4.55 CHEESESOUP 0 0.00 1 3.13 0 0.00 1 1.14 CHERRIES 0 0.00 1 3.13 0 0.00 1 1.14 CHICKEN 2 6.90 1 3.13 0 0.00 3 3.41 CHINESFOOD 0 0.00 1 3.13 0 0.00 1 1.14 CLOWNS 0 0.00 1 3.13 0 0.00 1 1.14 COFFEE 0 0.00 1 3.13 0 0.00 1 1.14 COKE 0 0.00 1 3.13 0 0.00 1 1.14 COOK 1 3.45 0 0.00 0 0.00 1 1.14 COOKIES 2 6.90 0 0.00 0 0.00 2 2.27 COUNTER 1 3.45 2 6.25 1 3 .70 4 4.55 CRACKERS 0 0.00 1 3.13 0 0.00 1 1.14 CRAYONS 1 3.45 0 0.00 0 0.00 1 1.14 CUPBOARDS 0 0.00 1 3.13 0 0.00 1 1.14 CUPS 1 3.45 2 6.25 2 7.41 5 5.68 107 i SUBJECT AGE-GROUP THREE YEARS FOUR YEARS FIVE YEARS TOTAL SAMPLE ITEM f % f % f % f % DECORATION 0 0.00 1 3.13 0 0.00 1 1.14 DOOR 3 10.34 1 3.13 2 7.41 6 6.82 DRIEDBANAN 0 0.00 0 0.00 1 3.70 1 1.14 DRINKS 1 3.45 .2 6.25 3 11.11 6 6.82 FISH 3 10.34 2 6.25 0 0.00 5 5.68 FISHNCHIPS 0 0.00 1 3.13 0 0.00 1 1.14 FLOOR 1 3.45 0 0.00 0 0.00 1 1.14 FLOWERS 0 0.00 2 6. 25 1 3.70 3 3.41 FOOD 13 44.83 17 53.13 12 44.44 42 47.73 FORKS 1 3.45 3 9.38 6 22.22 10 11.36 FORTUNCOOK 0 0.00 1 3.13 0 0.00 1 1.14 FRIEND 1 3.45 0 0.00 0 0.00 1 1.14 FRIES 0 0.00 0 0.00 1 3.70 1 1.14 FRYINGPAN 0 0.00 0 0.00 1 3.70 1 1.14 GARBAGCANS 0 0.00 1 3.13 0 0.00 1 1.14 GLASS 1 3.45 1 3.13 0 0.00 2 2.27 HAMBURGER 3 10.34 2 6.25 0 0.00 5 5.68 HOTDOG 0 0.00 0 0.00 1 3.70 1 1.14 ICECREAM 1 3.45 1 3.13 0 0.00 2 2.27 JUICE 0 0.00 0 0.00 2 7.41 2 2.27 KETCHUP 1 3.45 0 0.00 0 0.00 1 1.14 KEYOPENREST 0 0.00 1 3.13 0 0.00 1 1.14 KITCHEN 5 17.24 0 0.00 1 3.70 6 6.82 KNIVES 1 3.45 3 9.38 3 11.11 7 7.95 LADY 0 0.00 1 3.13 0 0.00 1 1.14 LAMPS 0 0.00 1 3.13 1 3.70 2 2.27 LEMONADE 0 0.00 1 3.13 0 0.00 1 1.14 LIGHTS 1 3.45 1 3.13 1 3.70 3 3.41 MAN 0 0.00 1 3.13 1 3.70 2 2.27 MESSENGER 1 3.45 0 0.00 0 0.00 1 1.14 MICROWAVE 0 0.00 1 3.13 0 0.00 1 1.14 MILK 1 3.45 0 0.00 2 7.41 3 3.41 MONEY 1 3.45 0 0.00 0 0.00 1 1.14 MUFFINS 0 0.00 1 3.13 0 0.00 1 1.14 NAPKIN 1 3.45 0 0.00 1 3.70 2 2.27 NOODLES 1 3.45 0 0.00 0 0.00 . 1 1.14 ONIONS 1 3 .45 0 0 .00 0 0.00 1 1.14 ORANGES 0 0.00 1 3.13 0 0.00 1 1.14 OVEN 0 0.00 0 0.00 1 3.70 1 1.14 PAPER 3 10.34 0 0.00 0 0.00 3 3.41 PARROTS 0 0.00 1 3.13 0 0.00 1 1.14 PAYERS 0 0.00 0 0.00 1 3.70 1 1.14 PEOPLE 4 13.79 11 34.38 13 48.15 28 31.82 PEOPLESELL 1 3.45 0 0.00 0 0.00 1 1.14 PICTURES 1 3.45 0 0.00 0 0.00 1 1.14 PIZZA 1 3.45 0 0.00 1 3.70 2 2.27 108 SUBJECT AGE-GROUP ITEM THREE YEARS FOUR YEARS FIVE YEARS TOTAL SAMPLE f % f % f % f % PLANTS 0 0.00 1 3.13 1 3.70 2 2.27 PLATES 5 17.24 4 12.50 8 29.63 17 19.32 POP 0 0.00 0 0.00 1 3.70 1 1.14 RADIOS 0 0.00 1 3.13 0 0.00 1 1.14 RAWFOOD 1 3.45 0 0.00 0 0.00 1 1.14 ROOF 0 0.00 1 3.13 0 0.00 1 1.14 SALAD 0 0.00 1 3.13 0 0.00 1 1.14 SANDWHICHES 1 3.45 0 0.00 0 0.00 1 1.14 SCALLOPS 0 0.00 0 0.00 1 3.70 1 1.14 SEAT 0 0.00 0 0.00 1 3.70 1 1.14 SERVERS 1 3.45 0 0.00 0 0.00 1 1.14 SHELVES 0 0.00 0 0.00 1 3.70 1 1.14 SONGS 1 3.45 0 0.00 0 0.00 1 1.14 SOUP 1 3.45 0 0.00 0 0.00 1 1.14 SPAGHETTI 1 3.45 1 3 .13 0 0.00 2 2.27 SPOONS 9 31.03 4 12.50 4 14.81 17 19.32 STAIRS 0 0.00 1 3.13 1 3.70 2 2.27 STEAKS 0 0.00 1 3.13 0 0.00 1 1.14 STOVE 0 0.00 2 6.25 1 3.70 3 3.41 SUSHI 0 0.00 0 0.00 1 3.70 1 1.14 TABLE 0 0.00 21 65.63 16 59.26 37 42.05 TEAPOT 1 3. 45 0 0.00 0 0.00 1 1.14 TOYS 2 6.90 4 12.50 0 0.00 6 6.82 TRAY 0 0.00 1 3.13 0 0.00 1 1.14 WAITER 1 3.45 0 0.00 1 3.70 2 2.27 WAITRESS 0 0.00 1 3.13 3 11.11 4 4.55 WALLS 0 0.00 1 3.13 0 0.00 1 1.14 WINDOWS 1 3.45 3 9.38 1 3.70 5 5.68 WINEGLASS 0 0.00 0 0.00 1 3.70 1 1.14 CATEGORY: TOYS ACROBATOY 0 0.00 0 0.00 1 3 .70 1 1.15 AIRPLANE 3 10.71 3 9.38 1 3.70 7 8.05 ANIMALS 1 3.57 0 0.00 0 0.00 1 1.15 ARMYTOY 0 0.00 1 3.13 1 3.70 2 2.30 BABIES 1 3.57 1 3.13 0 0.00 2 2.30 BALLS 2 7.14 0 0.00 4 14.81 6 6.90 BALLOONS 1 3.57 1 3.13 1 3.70 3 3.45 BARBIES 1 3.57 2 6.25 5 18.52 8 9.20 BARRETTES 0 0.00 0 0.00 3 11.11 3 3.45 BASEBALBAT 0 0.00 3 9.38 0 0.00 3 3.45 BATHTOYS 1 3.57 0 0.00 0 0.00 1 1.15 BATHTUBS 1 3.57 0 0.00 0 0.00 1 1.15 BEAR 2 7.14 0 0.00 1 3.70 3 3.45 109 SUBJECT AGE-GROUP THREE YEARS FOUR YEARS FIVE YEARS TOTAL SAMPLE ITEM f % f % f % f % BEDS 0 0.00 0 0.00 1 3.70 1 1.15 BELLS 0 0.00 0 0.00 2 7.41 2 2.30 BIKES 0 0.00 1 3.13 0 0.00 1 1.15 BINOCULAR 1 3.57 0 0.00 0 0.00 1 1.15 BLANKET 0 0.00 3 9.38 1 3.70 4 4.60 B-MOBILE 0 0.00 0 0.00 1 3.70 1 1.15 BLOCKS 1 3.57 0 0.00 0 0.00 1 1.15 BOATS 1 3.57 1 3.13 0 0.00 2 2.30 BOOKS 2 7.14 2 6.25 5 18.52 9 10.34 BOUNCEBABE 0 0.00 1 3.13 0 0.00 1 .. 1.15 BOXES 0 0.00 0 0.00 1 3.70 1 1.15 BMW 1 3.57 0 0.00 0 0.00 1 1.15 BUBBLEGUM 0 0.00 1 3.13 2 7.41 3 3 .45 BUCKETS 5 17.86 0 0.00 0 0.00 5 5.75 BUGS 1 3.57 0 0.00 0 0.00 1 1.15 BULL 0 0.00 1 3.13 0 0.00 1 1.15 BULLDOZER 0 0.00 1 3.13 1 3.70 2 2.30 BUNNIKINBWL 0 0.00 0 0.00 1 3.70 1 1.15 BUNNIKINPLT 0 0.00 0 0.00 1 3 .70 1 1.15 BUS 1 3.57 1 3.13 0 0.00 2 2.30 CALFRAISIN 0 0.00 1 3.13 0 0.00 1 1.15 CAMERA 0 0.00 0 0.00 2 7.41 2 2.30 CANDY 1 3.57 2 6.25 0 0.00 3 3.45 CARRIAGE 1 3.57 0 0.00 0 0.00 1 1.15 CARS 3 10.71 10 31.25 7 25.93 20 22.99 CAT 0 0.00 1 3.13 0 0.00 1 1.15 CEMENTRUCK 2 7.14 0 0.00 0 0.00 2 2.30 CHAIR 0 0.00 0 0.00 1 3.70 1 1.15 CHARLIETAPE 0 0.00 0 0.00 1 3.70 1 1.15 CHILDCASETE 0 0.00 1 3.13 0 0.00 1 1.15 CHOCOLATE 0 0.00 1 3.13 0 0.00 1 1.15 CLOCKS 0 0.00 1 3.13 0 0.00 1 1.15 CLOTHES 0 0.00 1 3.13 0 0.00 1 1.15 CLOWN 0 0.00 0 0.00 2 7.41 2 2.30 COLORBOOK 1 3.57 0 0.00 0 0.00 1 1.15 COMPUTER 1 3.57 1 3.13 0 0.00 2 2.30 CORVETTE 0 0.00 0 0.00 1 3.70 1 1.15 CUDDLYTOY 0 0.00 2 6.25 0 0.00 2 2.30 CRADLE 1 3.57 0 0.00 0 0.00 1 1.15 CRANES 0 0.00 1 3.13 0 0.00 1 1.15 CRAYONS 0 0.00 0 0.00 1 3.70 1 1.15 CUDDLIES 1 3.57 0 0.00 4 14.81 5 5.75 CUPBOARD 1 3 .57 0 0.00 1 3.70 2 2. 30 DIGSWITCH 1 3.57 1 3.13 0 0.00 2 2.30 DINOSAUR 2 7.14 0 0.00 1 3.70 3 3.45 DINOSMUG 0 0.00 0 0.00 1 3.70 1 1.15 110 SUBJECT AGE-GROUP THREE YEARS FOUR YEARS FIVE YEARS TOTAL SAMPLE ITEM f % f % f % f % DINOSPOST 1 3.57 0 0.00 0 0.00 1 1.15 DISHES 0 0.00 1 3.13 0 0.00 1 1.15 DOCTORKIT 1 3.57 0 0.00 0 0.00 1 1.15 DOGS 0 0.00 2 6.25 1 3.70 3 3.45 DOLLS 4 14.29 7 21.88 4 14.81 15 17.24 DUCKTAIL 0 0.00 1 3.13 0 0.00 1 1.15 DUMPTRUCK 2 7.14 1 3.13 0 0.00 3 3.45 EARRINGS 0 0.00 1 3.13 0 0.00 1 1.15 ELEPHANT 1 3 .57 0 0.00 0 0.00 1 1.15 FIREENGINE 1 3.57 1 3.13 0 0.00 2 2.30 FIREENGGUY 1 3 .57 0 0.00 0 0.00 1 1.15 FIREHOUSE 0 0.00 0 0.00 1 3.70 1 1.15 FLASHLIGHT 0 0.00 0 0.00 1 3.70 1 1.15 FLOWERS 0 0.00 0 0.00 1 3.70 1 1.15 FOX 1 3.57 0 0.00 0 0.00 1 1.15 GAMES 0 0.00 1 3.13 0 0.00 1 1.15 GARFIELD 0 0.00 0 0.00 1 3 .70 1 1.15 GHOSTBUSTCR 0 0.00 2 6.25 0 0.00 2 2.30 GHOSTBUST 1 3.57 1 3.13 3 11.11 5 5.75 GHOSTS 0 0.00 1 3.13 0 0.00 1 1.15 GIJOE 0 0.00 1 3.13 1 3.70 2 2.30 GLASSDOLL 0 0.00 2 6.25 . 0 0.00 2 2.30 GOFISHCARD 0 0.00 1 3.13 0 0.00 1 1.15 GUM 1 3.57 0 0.00 0 0.00 1 1.15 GUNS 0 0.00 2 6.25 0 0.00 2 2.30 GYM 0 0.00 1 3.13 0 0.00 1 1.15 HANDCUFF 0 0.00 1 3.13 0 0.00 1 1.15 HAUNTHOUS 0 0.00 0 0.00 1 3.70 1 1.15 HOSE 1 3.57 0 0.00 0 0.00 1 1.15 HORSE 2 7.14 1 3.13 1 3.70 4 4.60 HOUSE 0 0.00 1 3 .13 0 0.00 1 1.15 INSTRUMENT 0 0.00 1 3.13 0 0.00 1 1.15 JACKINBOX 0 0.00 1 3.13 0 0.00 1 1.15 JET 0 0.00 1 3.13 0 0.00 1 1.15 JUGGLTHING 1 3.57 0 0.00 0 0.00 1 1.15 KEYBOARD 0 0.00 0 0.00 1 3.70 1 1.15 KITCHEN 1 3.57 1 3.13 0 0.00 2 2. 30 KITTIES 0 0.00 1 3.13 0 0.00 1 1.15 LEGO 0 0.00 1 3.13 0 0.00 1 1.15 LIFEJACKET 1 3.57 0 0.00 0 0.00 1 1.15 LION 2 7.14 0 0.00 0 0.00 2 2.30 MAGICBOOK 0 0.00 1 3.13 0 0.00 1 1.15 MAKUP 0 0.00 0 0.00 1 3.70 1 1.15 MASKS 0 0.00 1 3.13 0 0.00 1 1.15 MERCEDIZ 1 3.57 0 0.00 0 0.00 1 1.15 MISMAKEUP 0 0.00 0 0.00 1 3.70 1 1.15 I l l SUBJECT AGE-GROUP ITEM THREE YEARS FOUR YEARS FIVE YEARS TOTAL SAMPLE f % f % f % f % MONSTERS 1 3.57 0 0.00 0 0.00 1 1.15 MOTORCYCLE 1 3.57 1 3.13 0 0.00 2 2.30 MOUSES 0 0.00 1 3.13 0 0.00 1 1.15 NINJATURT 1 3.57 1 3.13 0 0.00 2 2.30 NINTENDO 0 0.00 0 0.00 2 7.41 2 2.30 PENCILS 0 0.00 0 0.00 2 7.41 2 2.30 PEOPLELIT 3 10.71 3 9. 38 0 0.00 6 6.90 PETANIMAL 0 0.00 0 0.00 2 7.41 2 2.30 PHONE 0 0.00 3 9.38 1 3.70 4 4.60 PICKERUP 0 0.00 0 0.00 1 3.70 1 1.15 PICTURE 3 10.71 0 0.00 0 0.00 3 3.45 PITCHER 1 3.57 0 0.00 0 0.00 1 1.15 PIGGIES 0 0.00 1 3.13 0 0.00 1 1.15 PLAYHOUSE 0 0.00 0 0.00 1 3.70 1 1.15 PLAYMOBILE 0 0.00 0 0.00 1 3 .70 1 1.15 PLAYTREE 0 0.00 0 0.00 1 3.70 1 1.15 POLARBEAR 0 0.00 1 3.13 0 0.00 1 1.15 POLES 2 7.14 0 0.00 0 0.00 2 2.30 POLICECAR 1 3 .57 1 3.13 0 0.00 2 2.30 PONIES 0 0. 00 2 6.25 2 7.41 4 4.60 POTATOHEAD 1 3.57 0 0.00 0 0.00 1 1.15 POWERHWEELJ 0 0.00 1 3.13 0 0.00 1 1.15 PULLTOY 0 0.00 1 3.13 0 0.00 1 1.15 PUPPETS 1 3.57 1 3.13 0 0.00 2 2.30 PUZZLES 0 0.00 3 9.38 1 3 .70 4 4.60 RABBIT 1 3.57 0 0.00 0 0.00 1 1.15 RACINGCAR 1 3.57 2 6.25 0 0.00 3 3.45 REMOTECONTR 1 3.57 0 0.00 0 0.00 1 1.15 RHINO 1 3 .57 0 0.00 0 0.00 1 1.15 RINGS 0 0.00 1 3.13 0 0.00 1 1.15 ROBOTS 2 7.14 0 0.00 1 3.70 3 3.45 ROCKHORSE 1 3.57 0 0.00 0 0.00 1 1.15 RUBBERDUCK 0 0.00 1 3.13 0 0.00 1 1.15 SANDTRUCK 1 3.57 0 0.00 0 0.00 1 1.15 SCOOTER 0 0.00 0 0.00 1 3 .70 1 1.15 SEWINGMACH 0 0.00 .0 0.00 1 3.70 1 1.15 SHOVEL 3 10.71 0 0.00 0 0.00 3 3.45 SINK 0 0.00 0 0.00 1 3.70 1 1.15 SKATEBOARD 0 0.00 0 0.00 2 7.41 2 2.30 SLIDES 1 3.57 2 6.25 1 3.70 4 4.60 SNUGABOOS 0 0 .00 1 3.13 0 0.00 1 1.15 SPIDERS 0 0.00 1 3.13 0 0.00 1 1.15 SPORTSCAR 1 3.57 0 0.00 0 0.00 1 1.15 SQUIRTGUN 0 0.00 1 3.13 0 0.00 1 1.15 STAMP 0 0.00 0 0.00 1 3.70 1 1.15 STEAMSHOVE 0 0.00 1 3.13 0 0.00 1 1.15 112 SUBJECT AGE-GROUP THREE YEARS FOUR YEARS FIVE YEARS TOTAL SAMPLE ITEM f % f % f % f % STICKER 0 0.00 0 0.00 1 3.70 1 1.15 STICKONEARR 0 0.00 0 0.00 1 3.70 1 1.15 STORE 0 0.00 1 3.13 0 0.00 1 1.15 STORYTAPE 0 0.00 0 0.00 1 3.70 1 1.15 STOVE 0 0.00 2 6.25 0 0.00 2 2.30 STROLLER 1 3.57 0 0.00 0 0.00 1 1.15 STUFFEDANM 0 0.00 1 3.13 1 3.70 2 2.30 SWIMPOOL . 0 0.00 3 9. 38 0 0.00 3 3.45 SWINGS 0 0.00 1 3.13 0 0.00 1 1.15 SWORDS 0 0.00 1 3.13 1 3.70 2 2.30 TABLES 0 0.00 1 3.13 0 0.00 1 1.15 TAPERECORD 0 0.00 0 0.00 1 3.70 1 1.15 TBALLSTUFF 0 0.00 0 0.00 1 3.70 1 1.15 TEDDYBEAR 1 3.57 5 15.63 1 3.70 7 8.05 TENT 0 0.00 0 0.00 1 3 .70 1 1.15 TIGER 1 3.57 0 0.00 0 0.00 1 1.15 TINYFURNIT 0 0.00 0 0.00 1 3.70 1 1.15 TOPS 1 3.57 0 0.00 0 0.00 1 1.15 TOTEMPOLE 1 3.57 0 0.00 0 0.00 1 1.15 TOWTRUCK 1 3.57 0 0.00 0 0.00 1 1.15 TOYBOX 0 0.00 1 3.13 0 0.00 1 1.15 TOYFARM 0 0.00 1 3.13 0 0.00 1 1.15 TOYHAIR 0 0.00 0 0.00 1 3.70 1 1.15 TOYHOUSE 0 0.00 0 0.00 2 7.41 2 2.30 TRACTOR 0 0.00 1 3.13 2 7.41 3 3.45 TRAINS 2 7.14 3 9.38 2 7.41 7 8.05 TRANSFORMER 1 3.57 2 6.25 0 0.00 3 3.45 TREES 0 0.00 1 3.13 0 0.00 1 1.15 TRUCKS 5 17.86 7 21.88 4 14.81 16 18.39 UNICORN 0 0.00 0 0.00 1 3.70 1 1.15 VANS 0 0.00 1 3.13 0 0.00 1 1.15 VOLLEYBALL 1 3.57 0 0.00 0 0.00 1 1.15 WAGON 1 3.57 0 0.00 0 0.00 1 1.15 WATERGUNS 0 0.00 1 3.13 2 7.41 3 3.45 WHALES 0 0.00 1 3.13 0 0.00 1 1.15 WHISTLES 1 3.57 0 0.00 1 3.70 2 2.30 YOYO 0 0.00 0 0.00 1 3.70 1 1.15 CATEGORY: TRAVEL AMBULANCE 0 0.00 1 3.23 0 0.00 1 1.11 BIKE 8 25.81 3 9.68 8 28.57 19 21.11 BOAT 2 6.45 6 19.35 7 25.00 15 16.67 BUS 5 16.13 14 45.16 14 50.00 33 36.67 CAMEL 3 9.68 1 3.23 1 3.57 5 5.56 113 SUBJECT AGE-GROUP THREE YEARS FOUR YEARS FIVE YEARS TOTAL SAMPLE ITEMS f % f % f % f % CAMPVAN 0 0 00 1 3 23 0 0 00 1 1 .11 CAR 27 87 .10 30 96 77 25 89 .29 82 91 .11 CARRIAGE 0 0 00 2 6. 45 0 0 00 2 2 .22 DOG 1 3 23 0 0 00 0 0 00 1 1 .11 DUMPTRUCK 1 3 23 0 0. 00 0 0. 00 1 1 .11 ELEPHANT 1 3 23 0 0 00 0 0 00 1 1 .11 FERRY 0 0 00 3 9 68 5 17 86 8 8 .89 GARBAGTRUCK 1 3 .23 0 0 00 0 0 .00 1 1 .11 HELICOPTOR 3 9 68 6 19. 35 2 7 14 11 12 .22 HOMEBOAT 1 3 .23 0 0 00 0 0 .00 1 1 .11 HORSE 7 22 58 9 29. 03 6 21 43 22 24 .44 HOTAIRBALL 0 0 .00 1 3 23 0 0 .00 1 1 .11 JEEP 0 0 00 2 6 45 2 7 14 4 4 .44 JET 1 3 23 3 9 68 2 7 .14 6 6 .67 MOTORCYCLE 3 9 68 4 12. 90 1 3 57 8 8 .89 MOTORHOME 0 0 .00 1 3 23 0 0 .00 1 1 .11 MOVINGVAN 0 0 00 0 0. 00 1 3 57 1 1 .11 PLANE 9 29 .03 20 64 52 14 50 .00 43 47 .78 POLICECAR 1 3 23 2 6 45 0 0 00 3 3 .33 PONY 0 0 .00 1 3 .23 0 0 .00 1 1 .11 RACECAR 0 0 00 1 3 23 1 3 57 2 2 .22 ROCKET 1 3 .23 0 0 .00 0 0 .00 1 1 .11 SAILBOAT 0 0 00 1 3 23 0 0 00 1 1 .11 SCHOOLBUS 1 3 23 0 0 00 0 0 .00 1 1 .11 SCOOTER 1 3 23 0 0. 00 0 0 00 1 1 .11 SEABUS 1 3 .23 1 3 .23 1 3 .57 3 3 .33 SHIP 0 0 00 1 3 23 0 0 00 ' 1 1 .11 SKATEBOARD 0 0 .00 0 0 00 1 3 .57 1 1 .11 SKYTRAIN 1 3 23 0 0 00 2 7 14 3 3 .33 SLEIGH 1 3 .23 0 0 .00 0 0 .00 1 1 .11 SPACESHIP 1 3 23 1 3 23 0 0 00 2 2 .22 TAXI 4 12 .90 4 12 .90 4 14 .29 12 13 .33 TRACTOR 0 0 .00 1 3 23 0 0 00 1 1 .11 TRAILER 0 0 .00 1 3 23 1 3 57 2 2 .22 TRAIN 3 9 68 6 19. 35 8 28 57 17 18 .89 TRUCK 10 32 . 26 14 45 .16 12 42 .86 36 40 .00 VAN 6 19 35 9 29. 03 6 21 43 21 23 .33 WAGON 1 3 . 23 0 0 00 1 3 .57 2 2 .22 CATEGORY: ZOO ALLIGATOR 0 0 00 4 12 50 0 0 00 4 4 .35 BALOOGA 1 3 .13 0 0 .00 0 0 .00 1 1 .09 BATS 1 3 13 0 0. 00 1 3. 57 2 2 .17 BEARS 10 31 .25 5 15 63 7 25 .00 22 23 .91 114 SUBJECT AGE-GROUP THREE YEARS FOUR YEARS FIVE YEARS TOTAL SAMPLE ITEMS f 1 f • f 1 f % BEES 1 3 .13 0 0. 00 0 0 .00 1 1 09 BIGCATS 0 0 . 00 1 3 13 0 0 .00 1 1 .09 BIRDS 0 0 .00 8 25. 00 4 14 .29 12 13 04 BOACONSTR 0 0 .00 0 0 00 1 3 .57 1 1 .09 BUNNY 1 3 .13 1 3. 13 1 3 .57 3 3 26 BUTTERFLY 1 3 .13 0 0 .00 0 0 .00 1 1 .09 CAMEL 2 6 .25 4 12 50 1 3 .57 7 7 61 CATS 0 0 .00 2 6 .25 1 3 .57 3 3 .26 CHEETAH 1 3 .13 0 0. 00 0 0 .00 1 1 09 CHICKEN 1 3 .13 0 0 00 0 0 .00 1 1 .09 CHICKS 0 0 .00 1 3. 13 1 3 .57 2 2 17 COW 2 6 .25 1 3 13 2 7 . 14 5 5 .43 CROCODILE 0 0 .00 3 9 38 2 7 .14 5 5 43 DINOSAUR 1 3 .13 0 0 .00 0 0 .00 1 1 .09 DOGS 0 0 .00 1 3 13 2 7 .14 3 3 26 DOLPHIN 1 3 .13 0 0 .00 0 0 .00 1 1 .09 DONKEY 1 3 .13 0 0 00 2 7 .14 3 3 26 DRAGON 1 3 .13 0 0 .00 0 0 .00 1 1 .09 DUCKS 0 0 .00 1 3 13 4 14 .29 5 5 43 ELEPHANT 12 37 .50 15 46 .88 14 50 .00 41 44 .57 FISH 3 9 . 38 1 3 13 1 3 .57 5 5 43 FLAMINGO 1 3 . 13 0 0 .00 0 0 .00 1 1 .09 FOX 1 3 .13 1 3 13 0 0 .00 2 2 17 FROG 1 3 .13 0 0 .00 0 0 . 00 1 1 .09 GIRAFFFE 12 37 .50 18 56 25 12 42 .86 42 45 65 GORRILLA 1 3 .13 3 9 . 38 1 3 .57 5 5 .43 GUINEAPIG 0 0 .00 0 0 00 1 3 .57 1 1 09 HENS 0 0 .00 1 3 .13 0 0 .00 1 1 .09 HIPPO 3 9 . 38 5 15 63 3 10 .71 11 11 96 HORSE 5 15 .63 3 9 .38 2 7 .14 10 10 .87 INSECTS 0 0 .00 1 3 13 0 0 .00 1 1 09 JAGUAR 0 0 .00 1 3 .13 0 0 .00 1 1 .09 KANGAROO 4 12 .50 2 6 25 5 17 .86 11 11 96 KITTY 0 0 .00 1 3 .13 0 0 .00 1 1 .09 LAMBS 1 3 .13 0 0 00 2 7 .14 3 3 26 LAUGHYEEN 1 3 .13 0 0 .00 0 0 .00 1 1 .09 LEOPARD 0 0 .00 1 3 13 0 0 .00 1 1 09 LIONS 17 53 .13 16 50 .00 10 35 .71 43 46 .74 MICE 0 0 .00 2 6 25 1 3 .57 3 3 26 MONKEY 11 34 .38 11 34 .38 15 53 .57 37 40 22 MOO 1 3 .13 0 0 00 0 0 .00 1 1 09 MOOSE 0 0 . 00 1 3 . 13 0 0 .00 1 1 .09 OSTRICH 0 0 .00 2 6 25 0 0 .00 2 2 17 OTTERS 0 0 .00 0 0 .00 1 3 .57 1 1 .09 OWL 0 0 .00 0 0 00 1 3 .57 1 1 09 PARROTS 0 0 .00 1 3 .13 0 0 .00 1 1 .09 115 SUBJECT AGE-GROUP THREE YEARS FOUR YEARS FIVE YEARS TOTAL SAMPLE ITEMS f % f % f % f % PEACOCK 0 0.00 0 0.00 2 7.14 2 2.17 PENGUIN 0 0.00 1 3.13 2 7.14 3 3.26 PIGS 0 0.00 1 3.13 1 3.57 2 2.17 POLARBEAR 1 3.13 0 0.00 4 14.29 5 5.43 PONIES 0 0.00 1 3.13 1 3.57 2 2.17 PORCUPINE 0 0.00 1 3.13 0 0.00 1 1.09 PUSSYCAT 1 3.13 0 0.00 0 0.00 1 1.09 RABBIT 2 6.25 3 9.38 1 3.57 6 6.52 RACOON 0 0.00 0 0.00 1 3 .57 1 1.09 ROOSTER 1 3.13 1 3.13 0 0.00 2 2.17 SEALS 1 , 3.13 1 3.13 2 7.14 4 4.35 SHEEP 1 3.13 0 0.00 2 7.14 3 3.26 SLOTH 0 0.00 0 0.00 1 3.57 1 1.09 SNAKES 2 6.25 2 6.25 2 7.14 6 6. 52 SPIDER 0 0.00 1 3.13 0 0.00 1 1.09 SUQIRREL 1 3.13 1 3.13 2 7.14 4 4.35 TIGER 15 46.88 16 50.00 8 28.57 39 42.39 TURTLES 0 0.00 0 0.00 3 10.71 3 3.26 WHALES 4 12.50 2 6. 25 4 14.29 10 10.87 WILDPIGS 0 0.00 0 0.00 1 3.57 1 1.09 WOLVES 0 0.00 1 3 .13 1 3.57 2 2.17 ZEBRA 2 6.25 5 15.63 3 10.71 10 10.87 116 L i s t 2: Numerically Ordered Category Production Norms SUBJECT AGE-GROUP THREE YEARS FOUR YEARS FIVE YEARS TOTAL SAMPLE ITEMS f % f % f % f % CATEGORY: CLOTHES I i PANTS 21 70. ,00 30 96. ,77 23 82. ,14 74 82. ,22 SHIRT 14 46. .67 24 77. .42 20 71, .43 58 64. .44 SOCKS 10 33. ,33 14 45. ,16 17 60. .71 41 45. ,56 DRESS 10 33. .33 15 48. .39 9 32. .14 34 37, .78 SHORTS 8 26. ,67 11 35. ,48 . 9 32. .14 28 31. .11 SHOES 9 30. .00 10 32. .26 8 28, .57 27 30. .00 TSHIRT 7 23 . ,33 7 22. ,58 4 14. ,29 18 20. ,00 . UNDERWEAR 4 13 . .33 7 22. .58 5 17. .86 16 17. .78 SWEATER 6 20. ,00 5 16. ,13 2 7. .14 13 14. ,44 HAT 3 10. .00 4 12. ,90 4 14. . 29 11 12. .22 SKIRT 2 6. ,67 4 12. ,90 4 14. .29 10 11. ,11 JACKET 3 10. .00 2 6. .45 2 7. .14 7 7, .78 JEANS 0 0. ,00 3 9. ,68 4 14. .29 7 7. ,78 PANTIES 1 3. .33 3 9. .68 3 10, .71 7 7. .78 UNDERSHRT 2 6. ,67 0 0. ,00 4 14. .29 6 6. ,67 SHRTSLVDSHT 2 6. .67 0 0. .00 3 10, .71 5 5. .56 SWTSHRT 2 6. ,67 0 0. ,00 2 7. .14 4 4. ,44 COAT 2 6. .67 1 3. .23 0 0. .00 3 3. .33 PAJAMAS 0 0. ,00 3 9. .68 0 0. .00 3 3. ,33 BATHSUIT 2 6. .67 0 0. .00 0 0. .00 2 2. .22 BOOTS 0 0. ,00 1 3. .23 1 3. .57 2 2. ,22 EARRINGS 0 0. .00 2 6. .45 0 0. .00 2 2. .22 JAMMIES 2 6. ,67 0 0. ,00 0 0. ,00 2 2. ,22 SNOWPANT 0 0. .00 2 6. .45 0 0. .00 2 2. .22 STOCKING 1 3 . 33 0 . 0. 00 1 3. .57 2 2. .22 SUSPENDER 0 0. .00 0 0. .00 2 7, . 14 2 2. . 22 SWIMSUIT 2 6. ,67 0 0. .00 0 0. .00 2 2. .22 TROUSERS 0 0. .00 1 3. . 23 1 3, .57 2 2, .22 UNDIES 1 3, .33 1 3. .23 0 0. .00 2 2. .22 BARRETTE 1 3, . 33 0 0, .00 0 0, .00 1 1, .11 BLOUSE 0 0, .00 0 0, .00 1 3. .57 1 1. .11 BRA 1 3, .33 0 0. .00 0 0. .00 1 1, .11 CUTOFFS 0 0. .00 0 0. ,00 1 3. .57 1 1. .11 DRESSHIRT 0 0, .00 0 0, .00 1 3, .57 1 1, .11 DRESSPANT 0 0. .00 0 0. .00 1 3 . 57 1 1. .11 EXERCPANT 1 3, .33 0 0, .00 0 0, .00 1 1, .11 JOGPANTS 1 3 . 33 0 0. .00 0 0. .00 1 1. .11 JOGSHIRT 1 3. .33 0 0, .00 0 0, .00 1 1, .11 JOGSHORT 1 3. .33 0 0. .00 0 0, .00 1 1, .11 JUMPER 0 0, .00 , 1 3, .23 0 0, .00 1 1, .11 117 SUBJECT AGE-GROUP THREE YEARS FOUR YEARS FIVE YEARS TOTAL SAMPLE ITEMS f % f % f % f % LEGWARM 0 0.00 1 3.23 0 0.00 1 1.11 LEOTARD 0 0.00 1 3.23 0 0.00 1 1.11 LNGSLVDSHT 1 3.33 0 0.00 0 0.00 1 1.11 MITTS 0 0.00 0 0.00 1 3.57 1 1.11 NECKLACE 0 0.00 1 3.23 0 0.00 1 1.11 RAINCOAT 1 3.33 0 0.00 0 0.00 1 1.11 RINGS 0 0.00 1 3.23 0 0.00 1 1.11 SCARVES 0 0.00 0 0.00 1 3.57 1 1.11 SLIPPERS 0 0.00 0 0.00 1 3.57 1 1.11 SUIT 1 3.33 0 0.00 0 0.00 1 1.11 TIGHTS 0 0.00 1 3.23 0 0.00 1 1.11 TOWEL 1 3.33 0 0.00 0 0.00 1 1.11 TURTNECK 0 0.00 0 0.00 1 3 .57 1 1.11 UNDERPANTS 0 0.00 0 0.00 1 3.57 1 1.11 VESTS 0 0.00 1 3.23 0 0.00 1 1.11 CATEGORY: KITCHEN STOVES 12 40.00 15 48.39 8 28.57 35 39.33 TABLE 7 23.33 13 41.94 8 28.57 28 31.46 FORKS 7 23.33 7 22.58 12 42.86 26 29.21 FRIDGE 9 30.00 12 38.71 4 14.29 25 28.09 SPOONS 6 20.00 7 22.58 12 42.86 25 28.09 SINK 6 20.00 10 32.26 5 17.86 21 23.60 KNIVES 6 20.00 5 16.13 9 32.14 20 22.47 PLATES 7 23.33 3 9.68 8 28. 57 18 20. 22 CUPBOARDS 4 13.33 8 25.81 5 17.86 17 19.10 CHAIR 4 13.33 8 25.81 4 14.29 16 17.98 FOOD 10 33.33 2 6.45 4 14.29 16 17.98 POTS 1 3.33 9 29.03 6 21.43 16 17.98 CUPS 5 16.67 2 6.45 8 28.57 15 16.85 PANS 2 6.67 8 25.81 4 14.29 14 15.73 COUNTER 1 3.33 7 22.58 2 7.14 10 11.24 DISHES 4 13.33 4 12.90 0 0.00 8 8.99 OVENS 1 3.33 4 12.90 3 10.71 8 8.99 BOWL 3 10.00 0 0.00 5 17.86 8 8.99 MILK 4 13.33 1 3.23 0 0.00 5 5.62 FLOOR 2 6.67 2 6.45 0 0.00 4 4.49 DRAWERS 0 0.00 3 9.68 1 3.57 4 4.49 COOKIES 1 3.33 2 6.45 1 3.57 4 4.49 LIGHTS 0 0.00 0 0.00 3 10.71 3 3.37 CANDIES 2 6.67 1 3 . 23 0 0.00 3 3.37 FREEZER 2 6.67 1 3.23 0 0.00 3 3.37 WINDOWS 0 0.00 1 3.23 2 7.14 3 3.37 TEAKETTLE 1 3.33 1 3 .23 0 0.00 2 2.25 118 SUBJECT AGE-GROUP THREE YEARS FOUR YEARS FIVE YEARS TOTAL SAMPLE ITEMS f % f % f % f % WATER 1 3.33 1 3.23 0 0.00 2 2.25 DISHWASHER 1 3.33 1 3.23 0 0.00 2 2.25 DOORS 1 3.33 1 3.23 0 0.00 2 2.25 TOASTER 1 3.33 0 0.00 1 3.57 2 2.25 GLASS 0 0.00 1 3.23 1 3.57 2 2.25 MICROWAVES 0 0.00 0 0.00 2 7.14 2 2.25 FRUITROLLUP 1 3.33 0 0.00 0 0.00 1 1.12 MOMMIES 1 3.33 0 0.00 0 0.00 1 1.12 NOODLES 1 3.33 0 0.00 0 0.00 1 1.12 PAPER 1 3.33 0 0.00 0 0.00 1 1.12 PEOPLE 1 3.33 0 0.00 0 0.00 1 1.12 POP 1 3.33 0 0.00 0 0.00 1 1.12 RICEKRISPI 1 3.33 0 0.00 0 0.00 1 1.12 SANDWHICH 1 3.33 0 0.00 0 0.00 1 1.12 STOOLS 1 3.33 0 0.00 0 0.00 1 1.12 TV 1 3.33 0 0.00 0 0.00 1 1.12 APPLEJUICE 1 3.33 0 0.00 0 0.00 1 1.12 APRON 1 3.33 0 0. 00 0 0.00 1 1.12 BOXES 0 0.00 1 3.23 0 0.00 1 1.12 BREAD 1 3.33 0 0.00 0 0.00 1 1.12 CHICKENSOUP 1 3.33 0 0.00 0 0.00 1 1.12 CONTAINERS 0 0.00 1 3.23 0 0.00 1 1.12 COOKGLOVES 0 0.00 1 3.23 0 0.00 1 1.12 DADS 1 3.33 0 0.00 0 0.00 1 1.12 DRINK 1 3.33 0 0.00 0 0.00 1 1.12 EGGS 0 0.00 1 3.23 0 0.00 1 1.12 FRUIT 0 0.00 1 3.23 0 0.00 1 1.12 GARBAGE 0 0.00 1 3. 23 0 0.00 1 1.12 JUICE 0 0.00 1 3.23 0 0.00 1 1.12 PLASTICKNIVE 0 0.00 1 3.23 0 0.00 1 1.12 SHARPKNIVE 0 0.00 1 3.23 0 0.00 1 1.12 SPAGHETTI 0 0.00 1 3.23 0 0.00 1 1.12 SPONGES 0 0.00 1 3.23 0 0.00 1 1.12 TEACUPS 0 0.00 1 3.23 0 0.00 1 1.12 . TOAST 0 0.00 1 3.23 0 0.00 1 1.12 BEATERS 0 0.00 0 0.00 1 3.57 1 1.12 BOOKS 0 0.00 0 0.00 1 3 .57 1 1.12 BROOMCLOSET 0 0.00 0 0.00 1 3.57 1 1.12 ELECTCANOPEN 0 0.00 0 0.00 1 3.57 1 1.12 FOODCOLOR 0 0.00 0 0.00 1 3.57 1 1.12 JARS 0 0.00 0 0.00 1 3 .57 1 1.12 KETTLES 0 0.00 0 0.00 1 3. 57 1 1.12 KNIFESHARP 0 0.00 0 0.00 1 3.57 1 1.12 MUG 0 0.00 0 0.00 1 3.57 1 1.12 RADIO 0 0.00 0 0.00 1 3.57 1 1.12 SKELTCROSSB 0 0.00 0 0.00 1 3.57 1 1.12 119 SUBJECT AGE-GROUP THREE YEARS FOUR YEARS FIVE YEARS TOTAL SAMPLE ITEMS f % f % f % f % SPATULA 0 0.00 0 0.00 1 3.57 1 1.12 SUGAR 0 0.00 0 0.00 1 3.57 1 1.12 TAPS 0 0.00 0 0.00 1 3.57 1 1.12 WATERMELON 0 0.00 0 0.00 1 3.57 1 1.12 CATEGORY: PLAYGROUND SLIDES 25 80.65 27 84.38 24 85.71 76 83.52 SWINGS 20 64.52 29 90.63 22 78.57 71 78.02 CLIMBER 5 16.13 9 28.13 11 39.29 25 27.47 TEETTOTTER 5 16.13 9 28.17 4 14.29 18 19.80 POLE 4 12.90 1 3.13 9 32.14 14 15. 38 TIRESWING 4 12.90 3 9.38 6 21.43 13 14.29 LADDER 2 6.45 3 9.38 3 10.71 8 8.79 MERRYGOROUND 1 3.23 5 15.63 2 7.14 8 8.79 BRIDGES 2 6.45 3 9.38 2 7.14 7 7.69 MONKEYBARS 2 6.45 1 3.13 4 14.29 7 7.69 TIRES 1 3.23 3 9.38 2 7.14 6 6.59 SAND 2 6.45 3 9.38 1 3.57 6 6.59 STAIRS 2 6.45 3 9.38 1 3.57 6 6.59 SANDBOX 1 3.23 2 6.25 3 10.71 6 6.59 PEOPLE 4 12.90 1 3.13 1 3.57 6 6.59 BIRDS 0 0.00 4 12.50 0 0.00 4 4.40 TREES 0 0.00 3 9.38 1 3.57 4 4.40 HOUSES 2 6.45 2 6.25 0 0.00 4 4.40 DOGS 2 6.45 1 3.13 1 3.57 4 4.40 PLAYHOUSE 2 6.45 1 3.13 1 3.57 4 4.40 POND 2 6.45 0 0.00 2 7.14 4 4.40 JUNGLEGYM 1 3.23 2 6.25 0 0.00 3 3.30 SWIMPOOL 1 3.23 2 6.25 0 0.00 3 3.30 ROPES 0 0.00 1 3.13 2 7.14 3 3.30 ROUNDABOUT 0 0.00 1 3 .13 2 7.14 3 3.30 TREEHOUSE 2 6. 45 1 3.13 0 0.00 3 3.30 SCHOOL 0 0.00 2 6.25 0 0.00 2 2.20 BEACH 1 3.23 1 3.13 0 0.00 2 2.20 BOAT 1 3.23 1 3.13 0 0.00 2 2.20 CATS 1 3.23 1 3.13 0 0.00 2 2.20 CHILDREN 1 3.23 1 3.13 0 0.00 2 2.20 ELEPHANTS 1 3.23 1 3.13 0 0.00 2 2. 20 KIDS 1 3 . 23 1 3.13 0 0.00 2 2. 20 LEAVES 1 3.23 1 3.13 0 0.00 2 2.20 SEE-SAW 1 3.23 1 3.13 0 0.00 2 2. 20 TOYS 1 3.23 1 3.13 0 0.00 2 2.20 TUNNEL 1 3.23 1 3.13 0 0.00 2 2 .20 WATER 1 3 . 23 1 3.13 0 0.00 2 2.20 120 SUBJECT AGE-GROUP THREE YEARS FOUR YEARS FIVE YEARS TOTAL SAMPLE ITEMS f % f % f % f % BIKES FLOWERS GRASS HANGERS HILLS BUG BARS ANIMALS BALLOONS BLUESKY BUNNIES CARS TIREHOLES LITTLEHOUSE PICNICTABLE RUNNING SANDWHICHES TABLE WATERFOUNT ANT BLOCKS BOYS BUTTERFLY CHURCH CLOUDS COCACOLA DINOSAUR FISH FOOTBALL GIRLS HOPSCOTCH PEACOCKS SKATEBOARDS SNAILS SNAKE SOCCERTEAM STEERWHEEL TOWER WORM BALL CONCRETE CUPS DIGGERS DUCKS FRIEND GATE 0 0.00 0 0.00 0 0.00 0 0.00 0 0.00 2 6.45 1 3.23 0 0.00 0 0.00 0 0.00 0 0.00 0 0.00 0 0.00 0 0.00 0 0.00 0 0.00 0 0.00 0 0.00 0 0.00 1 3.23 1 3.23 1 3.23 1 3.23 1 3.23 1 3.23 1 3.23 1 3.23 1 3.23 1 3.23 1 3.23 1 3 . 23 1 3.23 1 3.23 1 3.23 1 3.23 1 3.23 1 3.23 1 3.23 1 3.23 0 0.00 0 0.00 0 0.00 0 0.00 0 0.00 0 0.00 0 0. 00 1 3.13 1 3.13 1 3.13 1 3.13 1 3.13 0 0.00 0 0.00 1 3.13 1 3.13 1 3.13 1 3.13 1 3.13 1 3.13 1 3.13 1 3.13 1 3 .13 1 3.13 1 3.13 1 3.13 0 0.00 0 0.00 0 0.00 0 0.00 0 0.00 0 0.00 0 0.00 0 0.00 0 0.00 0 0.00 0 0.00 0 0.00 0 0.00 0 0.00 0 0.00 0 0.00 0 0.00 0 0.00 0 0.00 0 0.00 0 0.00 0 0.00 0 0.00 0 0.00 0 0.00 0 0.00 0 0.00 1 3.57 1 3.57 1 3.57 1 3.57 1 3.57 0 0.00 1 3.57 0 0.00 0 0.00 0 0.00 0 0.00 0 0.00 0 0.00 0 0.00 0 0.00 0 0.00 0 0.00 0 0.00 0 0.00 0 0.00 0 0.00 0 0.00 0 0.00 0 0.00 0 0.00 0 0.00 0 0.00 0 0.00 0 0.00 0 0.00 0 0.00 0 0.00 0 0.00 0 0.00 0 0.00 0 0.00 0 0.00 0 0.00 0 0.00 1 3.57 1 3.57 1 3.57 1 3.57 1 3.57 1 3.57 1 3.57 2 2.20 2 2.20 2 2.20 2 2.20 2 2.20 2 2.20 2 2.20 1 1.10 1 1.10 1 1.10 1 1.10 1 1.10 1 1.10 1 1.10 1 1.10 1 1.10 1 1.10 1 1.10 1 1.10 1 1.10 1 1.10 1 1.10 1 1.10 1 1.10 1 1.10 1 1.10 1 1.10 1 1.10 1 1.10 1 1.10 1 1.10 1 1.10 1 1.10 1 1.10 1 1.10 1 1.10 1 1.10 1 1.10 1 1.10 1 1.10 1 1.10 1 1.10 1 1.10 1 1.10 1 1.10 1 1.10 121 SUBJECT AGE-GROUP THREE YEARS FOUR YEARS FIVE YEARS TOTAL SAMPLE ITEMS f % f % • f % f % GEESE 0 0.00 0 0.00 1 3 .57 1 1.10 HIGHTOPS 0 0.00 0 0.00 1 3.57 1 1.10 PLANTS 0 0.00 0 0.00 1 3.57 1 1.10 PLAYSEABUS 0 0. 00 0 0.00 1 3.57 1 1.10 RAKES 0 0.00 0 0.00 1 3.57 1 1.10 RAMP 0 0.00 0 0.00 1 3.57 1 1.10 RING 0 0.00 0 0.00 1 3.57 1 1.10 RIVER 0 0.00 0 0.00 1 3.57 1 1.10 SHOVEL 0 0.00 0 0.00 1 3.57 1 1.10 SPRINKLER 0 0.00 0 0.00 1 3.57 1 1.10 TRICYCLES 0 0.00 0 0.00 1 3 .57 1 1.10 V.TEGORY: RESTAURANT FOOD 13 44 .83 17 53.13 12 44.44 42 47.73 CHAIRS 7 24.14 18 56.25 13 48.15 38 43.18 TABLE 0 0.00 21 65.63 16 59.26 37 42.05 PEOPLE 4 13.79 11 34.38 13 48.15 28 31.82 PLATES 5 17.24 4 12.50 8 29.63 17 19.32 SPOONS 9 31.03 4 12. 50 4 14.81 17 19.32 FORKS 1 3 .45 3 9.38 6 22.22 10 11.36 KNIVES 1 3.45 3 9. 38 3 11.11 7 7.95 DOOR 3 10.34 1 3.13 2 7.41 6 6.82 DRINKS 1 3.45 2 6. 25 3 11.11 6 6.82 KITCHEN 5 17.24 0 0.00 1 3.70 6 6.82 TOYS 2 6.90 4 12.50 0 0.00 6 6.82 CUPS 1 3 .45 2 6.25 2. 7.41 5 5.68 FISH 3 10.34 2 6.25 0 0.00 5 5.68 HAMBURGER 3 10. 34 2 6. 25 0 0.00 5 5.68 WINDOWS 1 3.45 3 9. 38 1 3.70 5 5.68 BATHROOM 2 6.90 1 3.13 1 3.70 4 4.55 BOWLS 1 3.45 1 3.13 2 7.41 4 4.55 CANDY 3 10.34 0 0.00 1 3.70 4 4.55 CHEF 2 6.90 0 0.00 2 7.41 4 4.55 COUNTER 1 3.45 2 6.25 1 3.70 4 4.55 WAITRESS 0 0.00 1 3.13 3 11.11 4 4.55 CAKE 1 3.45 0 0.00 2 7.41 3 3.41 CHICKEN 2 6.90 1 3.13 0 0.00 3 3.41 FLOWERS 0 0.00 2 6.25 1 3.70 3 3.41 LIGHTS 1 3.45 1 3.13 1 3.70 3 3.41 MILK 1 3.45 0 0.00 2 7.41 3 3.41 PAPER 3 10.34 0 0.00 0 0.00 3 3.41 STOVE 0 0.00 2 6.25 1 3 .70 3 3.41 BAKER 0 0.00 2 6.25 0 0.00 2 2.27 122 SUBJECT AGE-GROUP THREE YEARS FOUR YEARS FIVE YEARS TOTAL SAMPLE ITEMS f % f % f % f % BALLOON 1 3 .45 1 3.13 0 0.00 2 2.27 COOKIES 2 6.90 0 0.00 0 0.00 2 2.27 GLASS 1 3.45 1 3.13 0 0.00 2 2.27 ICECREAM 1 3.45 1 3.13 0 0.00 2 2.27 JUICE 0 0.00 0 0.00 2 7.41 2 2. 27 LAMPS 0 0. 00 1 3.13 1 3.70 2 2.27 MAN 0 0.00 1 3.13 1 3.70 2 2.27 NAPKIN 1 3.45 0 0.00 1 3.70 2 2. 27 PIZZA 1 3 .45 0 0.00 1 3.70 2 2.27 PLANTS 0 0. 00 1 3.13 1 3.70 2 2.27 SPAGHETTI 1 3.45 1 3.13 0 0.00 2 2.27 STAIRS 0 0. 00 1 3.13 1 3.70 2 2.27 WAITER 1 3.45 0 0.00 1 3.70 2 2.27 APPLJUICE 0 0.00 0 0.00 1 3.70 1 1.14 BAKERMEN 0 0.00 0 0.00 1 3 .70 1 1.14 BOOKS 1 3 . 45 0 0.00 0 0.00 1 1.14 BOOTH 0 0.00 0 0.00 1 3 .70 1 1.14 BOOTS 1 3.45 0 0.00 0 0.00 1 1.14 BOX 0 0.00 0 0.00 1 3 .70 1 1.14 BUNNIES 0 0.00 1 3.13 0 0.00 1 1.14 CARPET 0 0.00 1 3 .13 0 0.00 1 1.14 CAT 0 0.00 0 0.00 1 3.70 1 1.14 CHEESESOUP 0 0.00 1 3.13 0 0.00 1 1.14 CHERRIES 0 0.00 1 3.13 0 0.00 1 1.14 CHINESFOOD 0 0.00 1 3.13 0 0.00 1 1.14 CLOWNS 0 0.00 1 3.13 0 0.00 1 1.14 COFFEE 0 0.00 1 3.13 0 0.00 1 1.14 COKE 0 0.00 1 3.13 0 0.00 1 1.14 COOK 1 3.45 0 0.00 0 0.00 1 1.14 CRACKERS 0 0.00 1 3.13 0 0.00 1 1.14 CRAYONS 1 3.45 0 0.00 0 0.00 1 1.14 CUPBOARDS 0 0.00 1 3.13 0 0.00 1 1.14 DECORATION 0 0.00 1 3.13 0 0.00 1 1.14 DRIEDBANAN 0 0.00 0 0.00 1 3.70 1 1.14 FISHNCHIPS 0 0.00 1 3.13 0 0.00 1 1.14 FLOOR 1 3 . 45 0 0.00 0 0.00 1 1.14 FORTUNCOOK 0 0.00 1 3.13 0 0.00 1 1.14 FRIEND 1 3.45 0 0.00 0 0.00 1 1.14 FRIES 0 0.00 0 0.00 1 3.70 1 1.14 FRYINGPAN 0 0.00 0 0.00 1 3.70 1 1.14 GARBAGCANS 0 0.00 1 3.13 0 0.00 1 1.14 HOTDOG 0 0.00 0 0.00 1 3.70 1 1.14 KETCHUP 1 3.45 0 0.00 0 0.00 1 1.14 KEYOPENREST 0 0.00 1 3.13 0 0.00 1 1.14 LADY 0 0.00 1 3.13 0 0.00 1 1.14 123 SUBJECT AGE-GROUP [TEMS THREE YEARS FOUR YEARS FIVE YEARS TOTAL SAMPLE f % f % f % f % LEMONADE 0 0.00 1 3.13 0 0.00 1 1.14 MESSENGER 1 3.45 0 0.00 0 0.00 1 1.14 MICROWAVE 0 0.00 1 3.13 0 0.00 1 1.14 MONEY 1 3.45 0 0.00 0 0.00 1 1.14 MUFFINS 0 0.00 1 3.13 0 0.00 1 1.14 NOODLES 1 3.45 0 0.00 0 0.00 1 1.14 ONIONS 1 3.45 0 0.00 0 0.00 1 1.14 ORANGES 0 0.00 1 3.13 0 0.00 1 1.14 OVEN 0 0.00 0 0.00 1 3.70 1 1.14 PARROTS 0 0.00 1 3.13 0 0.00 1 1.14 PAYERS 0 0.00 0 0.00 1 3.70 1 1.14 PEOPLESELL 1 3.45 0 0.00 0 0.00 1 1.14 PICTURES 1 3.45 0 0.00 0 0.00 1 1.14 POP 0 0.00 0 0.00 1 3.70 1 1.14 RADIOS 0 0.00 1 3.13 0 0.00 1 1.14 RAWFOOD 1 3.45 0 0.00 0 0.00 1 1.14 ROOF 0 0.00 1 3.13 0 0.00 1 1.14 SALAD 0 0.00 1 3.13 0 0.00 1 1.14 SANDWICHES 1 3 .45 0 0.00 0 0.00 1 1.14 SCALLOPS 0 0.00 0 0.00 1 3.70 1 1.14 SEAT 0 0.00 0 0.00 1 3 .70 1 1.14 SERVERS 1 3 .45 0 0.00 0 0.00 1 1.14 SHELVES 0 0.00 0 0.00 1 3 .70 1 1.14 SONGS 1 3.45 0 0.00 0 0.00 1 1.14 SOUP 1 3.45 0 0.00 0 0.00 1 1.14 STEAKS 0 0.00 1 3.13 0 0.00 1 1.14 SUSHI 0 0.00 0 0.00 1 3.70 1 1.14 TEAPOT 1 3.45 0 0.00 0 0.00 1 1.14 TRAY 0 0 .00 1 3.13 0 0.00 1 1.14 WALLS 0 0.00 1 3.13 0 0.00 1 1.14 WINEGLASS 0 0.00 0 0.00 1 3.70 1 1.14 CATEGORY: TOYS CARS 3 10.71 10 31.25 7 25.93 20 22.99 TRUCKS 5 17. 86 7 21.88 4 14.81 16 18. 39 DOLLS 4 14.29 7 21.88 4 14.81 15 17. 24 BOOKS 2 7.14 2 6.25 5 18.52 9 10.34 BARBIES 1 3.57 2 6.25 5 18.52 8 9.20 AIRPLANE 3 10.71 3 9.38 1 3.70 7 8.05 TEDDYBEAR 1 3 .57 5 15.63 1 3.70 7 8.05 TRAINS 2 7.14 3 9.38 2 7.41 7 8.05 BALLS 2 7.14 0 0.00 4 14.81 6 6.90 PEOPLELIT 3 10.71 3 9.38 0 0.00 6 6.90 124 SUBJECT AGE-GROUP ITEMS THREE YEARS FOUR YEARS FIVE YEARS TOTAL SAMPLE f % f % f % f % BUCKETS 5 17.86 0 0.00 0 0.00 5 5.75 CUDDLIES 1 3.57 0 0.00 4 14.81 5 5.75 GHOSTBUST 1 3.57 1 3.13 3 11.11 5 5.75 BLANKET 0 0.00 3 9.38 1 3.70 4 4.60 HORSE 2 7.14 1 3.13 1 3.70 4 4.60 PHONE 0 0. 00 3 9.38 1 3.70 4 4.60 PONIES 0 0.00 2 6.25 2 7.41 4 4.60 PUZZLES 0 0.00 3 9.38 1 3.70 4 4.60 SLIDES 1 3 .57 2 6.25 1 3.70 4 4.60 BALLOONS 1 3.57 1 3.13 1 3.70 3 3.45 BARRETTES 0 0.00 0 0.00 3 11.11 3 3.45 BASEBALBAT 0 0.00 3 9.38 0 0.00 3 3.45 BEAR 2 7.14 0 0.00 1 3 .70 3 3.45 BUBBLEGUM 0 0.00 1 3.13 2 7.41 3 3.45 CANDY 1 3.57 2 6.25 0 0.00 3 3 .45 DINOSAUR 2 7.14 0 0.00 1 3.70 3 3.45 DOGS 0 0.00 2 6.25 1 3.70 3 3.45 DUMPTRUCK 2 7.14 1 3.13 0 0.00 3 3.45 PICTURE 3 10.71 0 0.00 0 0.00 3 3.45 RACINGCAR 1 3.57 2 6. 25 0 0.00 3 3.45 ROBOTS 2 7.14 0 0.00 1 3 .70 3 3.45 SHOVEL 3 10.71 0 0.00 0 0.00 3 3.45 SWIMPOOL 0 0.00 3 9.38 0 0.00 3 3.45 TRACTOR 0 0.00 1 3.13 2 7.41 3 3.45 TRANSFORMER 1 3 .57 2 6.25 0 0.00 3 3.45 WATERGUNS 0 0.00 1 3.13 2 7.41 3 3.45 ARMYTOY 0 0.00 1 3.13 1 3.70 2 2.30 BABIES 1 3.57 1 3.13 0 0.00 2 2.30 BELLS 0 0.00 0 0.00 2 7.41 2 2.30 BOATS 1 3.57 1 3.13 0 0.00 2 2.30 BULLDOZER 0 0.00 1 3.13 1 3.70 2 2.30 BUS 1 3.57 1 3.13 0 0.00 2 2.30 CAMERA 0 0.00 0 0.00 2 7.41 2 2.30 CEMENTRUCK 2 7.14 0 0.00 0 0.00 2 2. 30 CLOWN 0 0.00 0 0.00 2 7.41 2 2. 30 COMPUTER 1 3.57 1 3.13 0 0.00 2 2. 30 CUDDLYTOY 0 0.00 2 6.25 0 0.00 2 2.30 CUPBOARD 1 3.57 0 0.00 1 3.70 2 2. 30 DIGSWITCH 1 3.57 1 3.13 0 0.00 2 2.30 FIREENGINE 1 3.57 1 3.13 0 0.00 2 2.30 GHOSTBUSTCR 0 0.00 2 6.25 0 0.00 2 2. 30 GIJOE 0 0.00 1 3.13 1 3.70 2 2.30 GLASSDOLL 0 0.00 2 6.25 0 0.00 2 2.30 GUNS 0 0.00 2 6.25 0 0.00 2 2.30 KITCHEN 1 3.57 1 3.13 0 0.00 2 2.30 125 SUBJECT AGE-GROUP THREE YEARS FOUR YEARS FIVE YEARS TOTAL SAMPLE ITEMS f % f % f % f % LION 2 7.14 0 0.00 0 0.00 2 2.30 MOTORCYCLE 1 3.57 1 3.13 0 0.00 2 2.30 NINJATURT 1 3.57 1 3.13 0 0.00 2 2.30 NINTENDO 0 0.00 0 0.00 2 7.41 2 2.30 PENCILS 0 0.00 0 0.00 2 7.41 2 2.30 PETANIMAL 0 0.00 0 0.00 2 7.41 2 2.30 POLES 2 7.14 0 0.00 0 0.00 2 2. 30 POLICECAR 1 3.57 1 3.13 0 0.00 2 2.30 PUPPETS 1 3.57 1 3.13 0 0.00 2 2. 30 SKATEBOARD 0 0.00 0 0.00 2 7.41 2 2.30 STOVE 0 0.00 2 6.25 0 0.00 2 2.30 STUFFEDANM 0 0.00 1 3.13 1 3.70 2 2.30 SWORDS 0 0.00 1 3.13 1 3.70 2 2.30 TOYHOUSE 0 0. 00 0 0.00 2 7.41 2 2.30 WHISTLES 1 3.57 0 0.00 1 3.70 2 2.30 ACROBATOY 0 0.00 0 0.00 1 3.70 1 1.15 ANIMALS 1 3.57 0 0.00 0 0.00 1 1.15 BATHTOYS 1 3.57 0 0.00 0 0.00 1 1.15 BATHTUBS 1 3.57 0 0.00 0 0.00 1 1.15 BEDS 0 0.00 0 0.00 1 3.70 1 1.15 BIKES 0 0.00 1 3.13 0 0.00 1 1.15 BINOCULAR 1 3.57 0 0.00 0 0.00 1 1.15 B-MOBILE 0 0.00 0 0.00 1 3 .70 1 1.15 BLOCKS 1 3.57 0 0.00 0 0.00 1 1.15 BOUNCEBABE 0 0.00 1 3.13 0 0.00 1 1.15 BOXES 0 0.00 0 0.00 1 3.70 1 1.15 BMW 1 3.57 0 0.00 0 0.00 1 1.15 BUGS 1 3.57 0 0.00 0 0.00 1 1.15 BULL 0 0.00 1 3.13 0 0.00 1 1.15 BUNNIKINBWL 0 0.00 0 0.00 1 3.70 1 1.15 BUNNIKINPLT 0 0.00 0 0.00 1 3.70 1 1.15 CALFRAISIN 0 0.00 1 3.13 0 0.00 1 1.15 CARRIAGE 1 3.57 0 0.00 0 0.00 1 1.15 CAT 0 0.00 1 3.13 0 0.00 1 1.15 CHAIR 0 0.00 0 0.00 1 3 .70 1 1.15 CHARLIETAPE 0 0.00 0 0.00 1 3.70 1 1.15 CHILDCASETE 0 0.00 1 3.13 0 0.00 1 1.15 CHOCOLATE 0 0.00 1 3.13 0 0.00 1 1.15 CLOCKS 0 0.00 1 3.13 0 0.00 1 1.15 CLOTHES 0 0.00 1 3.13 0 0.00 1 1.15 COLORBOOK 1 3.57 0 0.00 0 0.00 1 1.15 CORVETTE 0 0. 00 0 0.00 1 3.70 1 1.15 CRADLE 1 3.57 0 0.00 0 0.00 1 1.15 CRANES 0 0.00 1 3.13 0 0.00 1 1.15 CRAYONS 0 0.00 0 0.00 1 3.70 1 1.15 126 SUBJECT AGE-GROUP ITEMS THREE YEARS FOUR YEARS FIVE YEARS TOTAL SAMPLE f % f % f % f % DINOSMUG 0 0.00 0 0.00 1 3.70 1 1.15 DINOSPOST 1 3.57 0 0. 00 0 0.00 1 1.15 DISHES 0 0.00 1 3.13 0 0.00 1 1.15 DOCTORKIT 1 3.57 0 0.00 0 0.00 1 1.15 DUCKTAIL 0 0.00 1 3.13 0 0.00 1 1.15 EARRINGS 0 0.00 1 3.13 0 0.00 1 1.15 ELEPHANT 1 3.57 0 0.00 0 0.00 1 1.15 FIREENGGUY 1 3.57 0 0.00 0 0.00 1 1.15 FIREHOUSE 0 0.00 0 0.00 1 3.70 1 1.15 FLASHLIGHT 0 0.00 0 0.00 1 3.70 1 1.15 FLOWERS 0 0.00 0 0.00 1 3.70 1 1.15 FOX 1 3.57 0 0.00 0 0.00 1 1.15 GAMES 0 0.00 1 3.13 0 0.00 1 1.15 GARFIELD 0 0.00 0 0.00 1 3.70 1 1.15 GHOSTS 0 0 .00 1 3.13 0 0.00 1 1.15 GOFISHCARD 0 0.00 1 3.13 0 0.00 1 1.15 GUM 1 3.57 0 0.00 0 0.00 1 1.15 GYM 0 0.00 1 3.13 0 0.00 1 1.15 HANDCUFF 0 0.00 1 3.13 0 0.00 1 1.15 HAUNTHOUS 0 0.00 0 0.00 1 3.70 1 1.15 HOSE 1 3.57 0 0.00 0 0.00 1 1.15 HOUSE 0 0.00 1 3.13 0 0.00 1 1.15 INSTRUMENT 0 0.00 1 3.13 0 0.00 1 1.15 JACKINBOX 0 0.00 1 3.13 0 0.00 1 1.15 JET 0 0.00 1 3.13 0 0.00 1 1.15 JUGGLTHING 1 3.57 0 0.00 0 0.00 1 1.15 KEYBOARD 0 0.00 0 0.00 1 3.70 1 1.15 KITTIES 0 0.00 1 3.13 0 0.00 1 1.15 LEGO 0 0.00 1 3.13 0 0.00 1 1.15 LIFEJACKET 1 3.57 0 0.00 0 0.00 1 1.15 MAGICBOOK 0 0.00 1 3.13 0 0.00 1 1.15 MAKUP 0 0.00 0 0.00 1 3.70 1 1.15 MASKS 0 0.00 1 3.13 0 0.00 1 1.15 MERCEDIZ 1 3 . 57 0 0.00 0 0.00 1 1.15 MISMAKEUP 0 0.00 0 0.00 1 3.70 1 1.15 MONSTERS 1 3.57 0 0.00 0 0.00 1 1.15 MOUSES 0 0.00 1 3.13 0 0.00 1 1.15 PICKERUP 0 0.00 0 0.00 1 3.70 1 1.15 PITCHER 1 3.57 0 0.00 0 0.00 1 1.15 PIGGIES 0 0.00 1 3.13 0 0.00 1 1.15 PLAYHOUSE 0 0.00 0 0.00 1 3.70 1 1.15 PLAYMOBILE 0 0.00 0 0.00 1 3.70 1 1.15 PLAYTREE 0 0.00 0 0.00 1 3.70 1 1.15 POLARBEAR 0 0.00 1 3.13 0 0.00 1 1.15 POTATOHEAD 1 3.57 0 0.00 0 0.00 1 1.15 POWERHWE ELJ 0 0.00 1 3.13 0 0.00 1 1.15 127 SUBJECT AGE-GROUP ITEMS THREE YEARS FOUR YEARS FIVE YEARS TOTAL SAMPLE f % f % f % f % PULLTOY 0 0.00 1 3.13 0 0.00 1 1.15 RABBIT 1 3.57 0 0.00 0 0.00 1 1.15 REMOTECONTR 1 3.57 0 0.00 0 0.00 1 1.15 RHINO 1 3.57 0 0.00 0 0.00 1 1.15 RINGS 0 0.00 1 3.13 0 0.00 1 1.15 ROCKHORSE 1 3.57 0 0.00 0 0.00 1 1.15 RUBBERDUCK 0 0.00 1 3.13 0 0.00 1 1.15 SANDTRUCK 1 3.57 0 0.00 0 0.00 1 1.15 SCOOTER 0 0.00 0 0.00 1 3.70 1 1.15 SEWINGMACH 0 0.00 0 0.00 1 3.70 1 1.15 SINK 0 0.00 0 0.00 1 3.70 1 1.15 SNUGABOOS 0 0.00 1 3.13 0 0.00 1 1.15 SPIDERS 0 0.00 1 3.13 0 0.00 1 1.15 SPORTSCAR 1 3.57 0 0.00 0 0.00 1 1.15 SQUIRTGUN 0 0.00 1 3.13 0 0.00 1 1.15 STAMP 0 0.00 0 0.00 1 3.70 1 1.15 STEAMSHOVE 0 0.00 1 3 .13 0 0.00 1 1.15 STICKER 0 0.00 0 0.00 1 3.70 1 1.15 STICKONEARR 0 0.00 0 0.00 1 3.70 1 1.15 STORE 0 0.00 1 3.13 0 0.00 1 1.15 STORYTAPE 0 0.00 0 0.00 1 3 .70 1 1.15 STROLLER 1 3. 57 0 0.00 0 0.00 1 1.15 SWINGS 0 0.00 1 3.13 0 0.00 1 1.15 TABLES 0 0.00 1 3.13 0 0.00 1 1.15 TAPERECORD 0 0.00 0 0.00 1 3 .70 1 1.15 TBALLSTUFF 0 0.00 0 0.00 1 3.70 1 1.15 TENT 0 0.00 0 0.00 1 3 .70 1 1.15 TIGER 1 3.57 0 0. 00 0 0.00 1 1.15 TINYFURNIT 0 0.00 0 0.00 1 3.70 1 1.15 TOPS 1 3.57 0 0.00 0 0.00 1 1.15 TOTEMPOLE 1 3 .57 0 0.00 0 0.00 1 1.15 TOWTRUCK 1 3.57 0 0.00 0 0.00 1 1.15 TOYBOX 0 0.00 1 3.13 0 0.00 1 1.15 TOYFARM 0 0.00 1 3.13 0 0.00 1 1.15 TOYHAIR 0 0.00 0 0.00 1 3.70 1 1.15 TREES 0 0.00 1 3.13 0 0. 00 1 1.15 UNICORN 0 0.00 0 0.00 1 3.70 1 1.15 VANS 0 0.00 1 3.13 0 0.00 1 1.15 VOLLEYBALL 1 3 .57 0 0.00 0 0.00 1 1.15 WAGON 1 3.57 0 0.00 0 0.00 1 1.15 WHALES 0 0.00 1 3.13 0 0.00 1 1.15 YO-YO 0 0.00 0 0.00 1 3.70 1 1.15 128 SUBJECT AGE-GROUP THREE YEARS FOUR YEARS FIVE YEARS TOTAL SAMPLE ITEMS f % f % f % f % CATEGORY: TRAVEL CAR 27 87 .10 30 96 77 25 89 29 82 91 .11 PLANE 9 29 .03 20 64 .52 14 50 .00 43 47 .78 TRUCK 10 32 .26 14 45 16 12 42 86 36 40 .00 BUS 5 16 .13 14 45 .16 14 50 .00 33 36 .67 HORSE 7 22 58 9 29 03 6 21 43 22 24 .44 VAN 6 19 . 35 9 29 .03 6 21 .43 21 23 .33 BIKE 8 25 81 3 9 68 8 28 57 19 21 .11 TRAIN 3 9 .68 6 19 .35 8 28 .57 17 18 .89 BOAT 2 6 45 6 19. 35 7 25. 00 15 16 .67 TAXI 4 12 .90 4 12 90 4 14 .29 12 13 .33 HELICOPTOR 3 9 68 6 19 35 2 7 14 11 12 . 22 FERRY 0 0 .00 3 9 68 5 17 .86 8 8 .89 MOTORCYCLE 3 9 68 4 12 90 1 3 57 8 8 .89 JET 1 3 . 23 3 9 68 2 7 .14 6 6 .67 CAMEL 3 9 68 1 3 23 1 3 57 5 5 .56 JEEP 0 0 .00 2 6 .45 2 7 .14 4 4 .44 POLICECAR 1 3 23 2 6 45 0 0 00 3 3 .33 SEABUS 1 3 .23 1 3 23 1 3 .57 3 3 .33 SKYTRAIN 1 3 23 0 0 00 2 7 14 3 3 .33 CARRIAGE 0 0 00 2 6 45 0 0 .00 2 2 . 22 RACECAR 0 0 00 1 3 23 1 3 57 2 2 .22 SPACESHIP 1 3 .23 1 3 23 0 0 00 2 2 .22 TRAILER 0 0 00 1 3 23 1 3 57 2 2 .22 WAGON 1 3 . 23 0 0 00 1 3 .57 2 2 . 22 AMBULANCE 0 0 00 1 3. 23 0 0 00 1 1 .11 CAMPVAN 0 0 .00 1 3 23 0 0 .00 1 1 .11 DOG 1 3 23 0 0 00 0 0. 00 1 1 .11 DUMPTRUCK 1 3 .23 0 0 00 0 0 .00 1 1 .11 ELEPHANT 1 3 23 0 0 00 0 0 00 1 1 .11 GARBAGTRUCK 1 3 .23 0 0 00 0 0 .00 1 1 .11 HOMEBOAT 1 3 23 0 0. 00 0 0. 00 1 1 .11 HOTAIRBALL 0 0 .00 1 3 23 0 0 .00 1 1 .11 MOTORHOME 0 0 00 1 3 . 23 0 0. 00 1 1 .11 MOVINGVAN 0 0 00 0 0 00 1 3 57 1 1 .11 PONY 0 0 00 1 3 . 23 0 0. 00 1 1 .11 ROCKET . 1 3 23 0 0 00 0 0 00 1 1 .11 SAILBOAT 0 0. 00 1 3. 23 0 0. 00 1 1 .11 SCHOOLBUS 1 3 23 0 0 00 0 0 00 1 1 .11 SCOOTER 1 3 . 23 0 0. 00 0 0. 00 1 1 .11 SHIP 0 0 00 1 3 23 0 0 00 1 1 .11 SKATEBOARD 0 0. 00 0 0. 00 1 3. 57 1 1 .11 SLEIGH 1 3 23 0 0 00 0 0 00 1 1 .11 TRACTOR 0 0. 00 1 3. 23 0 0. 00 1 1 .11 SUBJECT AGE-GROUP THREE YEARS FOUR YEARS FIVE YEARS TOTAL SAMPLE ITEMS f % f 1 f % f % CATEGORY: ZOO LIONS 17 53 .13 16 50, .00 10 35, .71 43 46 .74 GIRAFFFE 12 37 .50 18 56, .25 12 42, .86 42 45 .65 ELEPHANT 12 37 .50 15 46, .88 14 50, .00 41 44 .57 TIGER 15 46 . 88 16 50, .00 8 28, .57 39 42 .39 MONKEY 11 34 .38 11 34, .38 15 53, .57 37 40 . 22 BEARS 10 31 .25 5 15, .63 7 25, • 00 22 23 .91 BIRDS 0 0 .00 8 25, .00 4 14. .29 12 13 .04 HIPPO 3 9 .38 5 15, .63 3 10, .** 11 11 .96 KANGAROO 4 12 .50 2 6, ,25 5 17, .86 11 11 .96 HORSE 5 15 .63 3 9, .38 2 7, .14 10 10 .87 WHALES 4 12 .50 2 6, .25 4 14, .29 10 10 .87 ZEBRA 2 6 .25 5 15, .63 3 10, .71 10 10 .87 CAMEL 2 6 . 25 4 12. .50 1 3 . 57 7 7 .61 RABBIT 2 6 . 25 3 9, .38 1 3, .57 6 6 .52 SNAKES 2 6 .25 2 6. ,25 2 7. .14 6 6 .52 COW 2 6 .25 1 3, .13 2 7, .14 5 5 .43 CROCODILE 0 0 .00 3 9. ,38 2 7, ,14 5 5 .43 DUCKS 0 0 . 00 1 3, .13 4 14. . 29 5 5 .43 FISH 3 9 .38 1 3. ,13 1 3 , 57 5 5 .43 GORRILLA 1 3 .13 3 9, .38 1 3, .57 5 5 .43 POLARBEAR 1 3 .13 0 0. ,00 4 14. ,29 5 5 .43 ALLIGATOR 0 0 .00 4 12, , 50 0 0, .00 4 4 . 35 SEALS 1 3 .13 1 3 . ,13 2 7. ,14 4 4 .35 SQUIRREL 1 3 .13 1 3, .13 2 7, .14 4 4 .35 BUNNY 1 3 .13 1 3 . 13 1 3 . ,57 3 3 .26 CATS 0 0 .00 2 6, . 25 1 3, .57 3 3 .26 DOGS 0 0 .00 1 3 . 13 2 7. .14 3 3 .26 DONKEY 1 3 .13 0 0. .00 2 7. .14 3 3 .26 LAMBS 1 3 .13 0 0. ,00 2 7. .14 3 3 .26 MICE 0 0 .00 2 6. .25 1 3. .57 3 3 .26 PENGUIN 0 0 .00 1 3. ,13 2 7. ,14 3 3 . 26 SHEEP 1 3 .13 0 0, .00 2 7, .14 3 3 .26 TURTLES 0 0 .00 0 0. ,00 3 10. .71 3 3 .26 BATS 1 3 .13 0 0. ,00 1 3. ,57 2 2 .17 CHICKS 0 0 .00 1 3. ,13 1 3 . ,57 2 2 .17 FOX 1 3 .13 1 3. , 13 0 0. ,00 2 2 .17 OSTRICH 0 0 .00 2 6. ,25 0 0. ,00 2 2 .17 PEACOCK 0 0 .00 0 0. ,00 2 7. ,14 2 2 .17 PIGS 0 0 .00 1 3 . 13 1 3 . 57 2 2 . 17 PONIES 0 0 .00 1 3. ,13 1 3. ,57 2 2 .17 ROOSTER 1 3 .13 1 3 . 13 0 0. ,00 2 2 .17 WOLVES 0 0 .00 1 3. ,13 1 3. ,57 2 2 .17 BALOOGA 1 3 .13 0 0. 00 0 0. 00 1 1 .09 130 SUBJECT AGE-GROUP THREE YEARS FOUR YEARS FIVE YEARS TOTAL SAMPLE ITEMS f % f % f % f % BEES BIGCATS BOACONSTR BUTTERFLY CHEETAH CHICKEN DINOSAUR DOLPHIN DRAGON FLAMINGO FROG GUINEAPIG HENS INSECTS JAGUAR KITTY LAUGHYEEN LEOPARD MOO MOOSE OTTERS OWL PARROTS PORCUPINE PUSSYCAT RACOON SLOTH SPIDER WILDPIGS 1 3.13 0 0.00 0 0.00 1 3.13 1 3.13 1 3.13 1 3.13 1 3.13 1 3.13 1 3.13 1 3.13 0 0.00 0 0.00 0 0.00 0 0.00 0 0.00 1 3.13 0 0.00 1 3.13 0 0.00 0 0.00 0 0.00 0 0.00 0 0.00 1 3.13 0 0.00 0 0.00 0 0.00 0 0.00 0 0.00 1 3.13 0 0.00 0 0.00 0 0.00 0 0.00 0 0.00 0 0.00 0 0.00 0 0.00 0 0.00 0 0.00 1 3.13 1 3.13 1 3.13 1 3.13 0 0.00 1 3.13 0 0.00 1 3.13 0 0.00 0 0.00 1 3.13 1 3.13 0 0.00 0 0. 00 0 0.00 1 3.13 0 0.00 0 0.00 0 0.00 1 3.57 0 0.00 0 0.00 0 0.00 0 0.00 0 0.00 0 0.00 0 0.00 0 0.00 1 3.57 0 0.00 0 0.00 0 0.00 0 0.00 0 0.00 0 0.00 0 0.00 0 0.00 1 3.57 1 3.57 0 0.00 0 0.00 0 0.00 1 3.57 1 3.57 0 0.00 1 3.57 1 1.09 1 1.09 1 1.09 1 1.09 1 1.09 1 1.09 1 1.09 1 1.09 1 1.09 1 1.09 1 1.09 1 1.09 1 1.09 1 1.09 1 1.09 1 1.09 1 1.09 1 1.09 1 1.09 1 1.09 1 1.09 1 1.09 1 1.09 1 1.09 1 1.09 1 1.09 1 1.09 1 1.09 1 1.09 131 APPF.NDIX D Cateaory Production,Histoqraphs TWENTY MOST COMMON ITEMS TWENTY MOST COMMON ITEMS 132 TWENTY MOST COMMON ITEMS 133 TWENTY MOST COMMON ITEMS TWENTY MOST COMMON ITEMS 134 TWENTY MOST COMMON ITEMS APPENDIX E Category L i n e Drawings and E l a b o r a t i v e Study C o n d i t i o n Questions Clothes Questions: Is a d r e s s something t h a t a g i r l would wear? Do people wear h a t s on t h e i r heads? Do you wear shoes o u t s i d e ? Do you wear s h o r t s on a sunny day? Do most people wear underwear under t h e i r c l o t h e s ? L i n e Drawings: 137 Zoo Questions: Do g i r a f f e s have long necks and l i v e i n the jungle? Do monkeys swing i n t r e e s and have long t a i l s ? Can kangaroos hop around on two legs? Do t i g e r s have s t r i p e s , b i g t e e t h and l i v e i n the jungle? Do bears l i k e honey and l i v e i n the f o r s t ? L i n e Drawings: 138 139 T r a v e l Questions: Can people s i t i n the f r o n t p a r t of a t r u c k t o get a r i d e ? Does a van have l o t s of room i n the back and go on the road? Does a bus c a r r y l o t s of people and d r i v e on roads? Can a t r a i n r i d e on r a i l w a y t r a c k s and c a r r y l o t s of people? Do you have t o peddle t o r i d e a bike? L i n e Drawings: • B Q B B B B Q ^ I 141 Playground Questions: Can you go up and down on a teeter-totter? Does a merry-go-round turn people around i n c i r c l e s ? Can you climb to the top of a climber and hang from the top? Do parks sometimes have toy bridges for kids to play on? Can fun things be made out of t i r e s for kids to play on? Line Drawings: 142 APPENDIX F A n a l y s i s of Variance Tables For Chapter Four O v e r a l l Anova Source SS df MS F P BETWEEN SUBJECTS Age E r r o r 6567.98 17630.312 2 33 3283.990 534.252 6.147 .005 WITHIN Study Age x E r r o r SUBJECTS Study 5916.174 4859.347 24578.729 1 2 33 5916.174 2429.674 744.810 7.943 3.262 .008 .049 T e s t Age x E r r o r T e s t 96814.323 4719.718 16084.313 2 2 33 96814.323 2359.859 487.403 198.633 4.842 <.001 .014 Study Age x E r r o r x T e s t Stdy x T s t 108.507 2283.681 15366.062 1 2 33 108.507 1141.840 465.638 .233 2.452 .632 .100 TOTAL 194929.145 143 Anova of Primina Data Source SS df MS F P BETWEEN SUBJECTS Age E r r o r 166.253 12236.625 2 33 83.127 370.807 .224 WITHIN Study Age x E r r o r SUBJECTS Study 2211.125 513.250 9681.125 1 2 33 2211.125 256.625 293.367 7.537 .875 .009 TOTAL 24808.378 71 144 Anova of Recall Data Source SS df MS F p BETWEEN SUBJECTS Age 11121.444 2 5560.722 8.544 .001 Error 21478.000 33 650.840 WITHIN SUBJECTS Study 3813.555 1 3813.555 4.158 .047 Age X Study 6629.778 2 3314.889 3.615 .037 Error 30263.667 33 917.081 TOTAL 73306.444 71 Simple Main Ef f e c t s of Recall Data MS F P Source SS df BETWEEEN SUBJECTS Between A at b± 1397.031 2 698.516 .891 Between A at fc>2 16349.290 2 8174.645 10.427 <.01 Within c e l l 51741.667 66 783.965 WITHIN SUBJECTS Between B at a-^  10249.013 1 10249.013 11.176 <.01 Between B at a 2 150.000 1 150.000 .164 Between B at a 3 42.773 1 42.773 .046 AB 6629.778 2 3314.889 3.615 .037 B x Ss w/in grps 30263.667 33 917.081 TOTAL 73306.444 71 

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