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UBC Theses and Dissertations

Discrimination and generalization in autistic children Adnan, Nurjehan 1973

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(A DISCRIMINATION AND GENERALIZATION IN AUTISTIC CHILDREN by NURJEHAN ADNAN B . A . , U n i v e r s i t y of B r i t i s h Columbia, 1971 A THESIS SUBMITTED IN PARTIAL FULFILMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF ARTS i n the Department of Psychology We accept t h i s thes i s as conforming to the required standard THE UNIVERSITY OF BRITISH COLUMBIA December, 1973 I n p r e s e n t i n g t h i s t h e s i s i n p a r t i a l f u l f i l m e n t o f t h e r e q u i r e m e n t s f o r an a d v a n c e d d e g r e e a t t h e U n i v e r s i t y o f B r i t i s h C o l u m b i a , I a g r e e t h a t t h e L i b r a r y s h a l l m a k e i t f r e e l y a v a i l a b l e f o r r e f e r e n c e a n d s t u d y . I f u r t h e r a g r e e t h a t p e r m i s s i o n f o r e x t e n s i v e c o p y i n g o f t h i s t h e s i s f o r s c h o l a r l y p u r p o s e s may be g r a n t e d by t h e H e a d o f my D e p a r t m e n t o r by h i s r e p r e s e n t a t i v e s . I t i s u n d e r s t o o d t h a t c o p y i n g o r p u b l i c a t i o n o f t h i s t h e s i s f o r f i n a n c i a l g a i n s h a l l n o t be a l l o w e d w i t h o u t my w r i t t e n p e r m i s s i o n . D e p a r t m e n t o f P ^ ^ O L Q C V The U n i v e r s i t y o f B r i t i s h C o l u m b i a V a n c o u v e r 8 , C a n a d a D a t e ^ e u v v ^ v ^ t ^  ABSTRACT The present study examined st imulus c o n t r o l i n a u t i s t i c c h i l d r e n . A matching-to-sample procedure was employed i n a l l experiments. In the f i r s t part of Experiment I , a u t i s t i c and c o n t r o l subjects were t ra ined to d i s c r i m i n a t e between a v e r t i c a l l i n e and a l i n e t i l t e d at an angle of 33 degrees from v e r t i c a l . Fo l lowing t r a i n i n g , subjects were given a g e n e r a l i z a t i o n tes t to determine the degree of dimensional c o n t r o l by l i n e t i l t . In the second part of Experiment I , subjects were t ra ined to d i s c r i m i n a t e between a v e r t i c a l l i n e and l i n e s t i l t e d p r o g r e s s i v e l y c lo ser to v e r t i c a l . Experiment II was a l so a t e s t for the degree of dimensional c o n t r o l by the l i n e t i l t . In Experiment I , the a u t i s t i c subjects took a greater number of t r i a l s than the contro l s to reach the c r i t e r i o n of 24 consecutive correc t t r i a l s . However, the d i f f e r e n c e i n the number of t r i a l s taken by the two groups was not l a r g e . There was a l so l i t t l e d i f f erence between the a u t i s t i c and c o n t r o l subjects i n part two of Experiment I . A l l of the a u t i s t i c subjects s u c c e s s f u l l y d i scr iminated between a v e r t i c a l l i n e and a 2 degree l i n e t i l t to a c r i t e r i o n of eight consecutive correc t t r i a l s . In the g e n e r a l i z a t i o n tes t s i n Experiments I and I I , there was l i t t l e d i f f e r e n c e between the a u t i s t i c and c o n t r o l subjects i n dimensional st imulus c o n t r o l . In Experiment I I I , the a u t i s t i c subjects were examined for a c q u i s i t i o n of a mult id imensional d i s c r i m i n a t i o n . Both a u t i s t i c and c o n t r o l subjects were t ra ined to match a standard st imulus wi th one of four comparison s t i m u l i that were v a r i e d i n shape and i n the presence and absence of a i s tar w i t h i n the shape. The a u t i s t i c subjects took a greater number of t r i a l s than the contro l s to reach the c r i t e r i o n of e ight consecutive correct t r i a l s . However, the d i f f erence between the a u t i s t i c and c o n t r o l subjects i n the number of t r i a l s taken to reach c r i t e r i o n was not l a r g e . In summary, the study found l i t t l e d i f f erence between a u t i s t i c and c o n t r o l subjects i n the a c q u i s i t i o n of simple or mult id imensional d i s -c r i m i n a t i o n . As w e l l , there was l i t t l e d i f f erence between the a u t i s t i c s and the contro l s i n dimensional st imulus c o n t r o l . The r e s u l t s of the study suggest that the a u t i s t i c c h i l d ' s problem i s not one of st imulus s e l e c t i v i t y . i i TABLE OF CONTENTS Chapter P a § e I . INTRODUCTION 1. Diagnost ic C r i t e r i a of E a r l y Childhood Autism 1 2. Stimulus Contro l i n A u t i s t i c C h i l d r e n 2 3. Purpose of Present Research. 25 I I . EXPERIMENTS 1. Experiment 1 28 Method 28 Resul t s 37 Di scuss ion 43 2. Experiment I I 44 Method 44 Resul ts 46 Di scuss ion 49 3. Experiment I I I 50 Method 50 Resul t s 52 D i scuss ion 54 I I I . DISCUSSION 55 REFERENCES 61 APPENDIX 6 6 i i i LIST OF TABLES Table page I . Number of t r i a l s taken by subjects to reach c r i t e r i o n of twenty-four consecutive correc t t r i a l s on the FR4 schedule during t r a i n i n g i n the f i r s t part of Experiment I . . . . 3 8 I I . Number of t r i a l s taken by subjects to reach c r i t e r i o n of e ight consecutive correc t t r i a l s i n Experiment I , part two 42 I I I . Number of t r i a l s taken by subjects to reach c r i t e r i o n of e ight consecutive correc t t r i a l s i n Experiment I I I 53 i v LIST OF FIGURES F igure page 1. Number of responses made by a u t i s t i c and c o n t r o l subjects to the var ious l i n e t i l t s during tes t for st imulus c o n t r o l i n Experiment I 40 2. T o t a l number of responses to n o n - v e r t i c a l comparison l i n e t i l t s made by a u t i s t i c and c o n t r o l subjects i n Experiment I , part one. . . 41 3. Number of responses made by a u t i s t i c and c o n t r o l subjects to the var ious l i n e t i l t s during tes t for st imulus c o n t r o l i n Experiment II 47 4. T o t a l number of responses to n o n - v e r t i c a l comparison l i n e t i l t s made by a u t i s t i c and c o n t r o l subjects i n Experiment I 48 v ACKNOWLEDGEMENTS I wish to thank my a d v i s o r s , Dr. D. M. W i l k i e and Dr . C. J . Tragakis for t h e i r ass i s tance and encouragement throughout the var ious phases of the study. I a l so wish to thank Mrs . Laura Willows and the s t a f f of L a u r e l House, and the P r i n c i p a l and teachers of the Holy T r i n i t y Elementary School for t h e i r most va luable cooperat ion . F i n a l l y , I would l i k e to thank. Br ian Sutherland for the drawing of the graphs, and D r . Ralph Kachanoff of Douglas H o s p i t a l , Montrea l , for h i s ideas on chi ldhood autism. v i CHAPTER I: INTRODUCTION Diagnost ic C r i t e r i a of E a r l y Childhood Autism E a r l y i n f a n t i l e (or childhood) autism was f i r s t d i s t i n g u i s h e d and labe led i n an a r t i c l e publ ished by Kanner i n 1943. Several i n v e s t i g a t o r s ( § _ . £ . , R u t t e r , 1968; Mahler , 1961; Creak, 1961; Rimland, 1964) have s ince then reported s i m i l a r c h a r a c t e r i s t i c s d e s c r i b i n g e a r l y chi ldhood autism. The l i t e r a t u r e reviewed by Ward and. Hanford (1968) suggests that the main c h a r a c t e r i s t i c features of the a u t i s t i c c h i l d are as fo l lows . F i r s t , the onset of the syndrome occurs at a very ear ly age. The c h i l d i s often described as being extremely a loof from the e a r l i e s t months of l i f e . He avoids eye-to-eye contact , avoids p h y s i c a l contact even wi th h i s parents , d i sp lays l i m i t e d v a r i a t i o n s i n f a c i a l expressions and i s unresponsive to v i s u a l and audi tory s t i m u l i . As w e l l , d i f f i c u l t y i n i n t e r a c t i n g wi th other c h i l d r e n i s a prominent and l o n g - l a s t i n g c h a r a c t e r i s t i c of a u t i s t i c c h i l d r e n . G e n e r a l l y , t h e i r behavior suggests an apparent l a c k of the a b i l i t y to be s o c i a l l y r e i n f o r c e d . Another commonly c i t e d c h a r a c t e r i s t i c of the a u t i s t i c c h i l d i s the l a c k of v e r b a l i n t e r a c t i o n with o thers . The c h i l d ' s speech i s l i m i t e d , never developing to a l e v e l appropr ia te for h i s age. The c h i l d i n c o r r e c t l y uses personal pronouns. E c h o l a l i a (repeating words j u s t sa id to the c h i l d ) i s f requent ly observed. Although words ure u t t e r e d , spontaneous conversat ion does not take p lace . In some cases, speech i s completely absent. The a u t i s t i c c h i l d i s often descr ibed as having an obsessive des i re for the maintenance of sameness. For example, the c h i l d , having s t a r t e d to 2 a r r a n g e b l o c k s i n a p a r t i c u l a r p a t t e r n , may p e r s i s t t o d o s o e v e n a f t e r t h e b l o c k s h a v e b e e n d i s a r r a n g e d . T h e t e n d e n c y t o m a i n t a i n s a m e n e s s o n t h e p a r t o f t h e a u t i s t i c c h i l d l e a d s t o a m a r k e d l i m i t a t i o n i n t h e v a r i e t y o f s p o n t a n e o u s a c t i v i t y i n t h e c h i l d ' s b e h a v i o r a l r e p e r t o i r e . I n a d d i t i o n , t h e r e i s a t e n d e n c y f o r t h e c h i l d t o e n g a g e i n s t e r e o t y p i c b e h a v i o r s u c h a s r o c k i n g a n d s p i n n i n g . L a c k o f a p p a r e n t n e u r o l o g i c a l d y s f u n c t i o n i s a n o t h e r m a j o r c h a r a c t e r -i s t i c o f e a r l y c h i l d h o o d a u t i s m . I n m o s t o f t h e c a s e s o f a u t i s m d e s c r i b e d i n t h e l i t e r a t u r e , t h e r e i s n o e v i d e n c e o f a n y o b s e r v a b l e n e u r o l o g i c a l d y s f u n c t i o n o r s e n s o r y d e f i c i t . E a r l y c h i l d h o o d a u t i s m i s m o s t i n t r i g u i n g i n v i e w o f t h e c h i l d ' s n o r m a l r e s p o n s e s t o s e n s o r y s t i m u l i i n t h e a b s e n c e o f a n y a p p a r e n t p h y s i o l o g i c a l d e f i c i t . S t i m u l u s C o n t r o l i n A u t i s t i c C h i l d r e n I n d e f i n i n g s t i m u l u s c o n t r o l , H e a r s t , B e s l e y a n d F a r t h i n g ( 1 9 7 0 ) h a v e p r o p o s e d t h a t a c l e a r d i s t i n c t i o n b e made b e t w e e n t w o t y p e s o f s t i m u l u s c o n t r o l : s t i m u l u s c o n t r o l b y a s p e c i f i c s t i m u l u s , a n d d i m e n s i o n a l s t i m u l u s  c o n t r o l w h i c h i s b e h a v i o r a l c o n t r o l b y d i f f e r e n t v a l u e s a l o n g a s p e c i f i c d i m e n s i o n o f a p a r t i c u l a r s t i m u l u s . S p e c i f i c s t i m u l u s c o n t r o l i s b e h a v i o r a l c o n t r o l b y t h e p r e s e n c e vs_ a b s e n c e o f a s p e c i f i c s t i m u l u s w h i c h p r o d u c e s a d i r e c t i o n a l e f f e c t o n r e s p o n d i n g t h a t " a c t s i n o p p o s i t i o n t o t h e n o r m a l l e v e l o f r e s p o n s e s t r e n g t h p r e v a i l i n g u n d e r t h e e x p e r i m e n t a l c o n d i t i o n s . " ( H e a r s t , e t a l , 1 9 7 0 , p . 3 7 5 ) . A n e x c i t a t o r y s t i m u l u s i s a s t i m u l u s t h a t d e v e l o p s t h e c a p a c i t y t o i n c r e a s e r e s p o n d i n g a b o v e t h e l e v e l o c c u r r i n g w h e n t h a t s t i m u l u s i s a b s e n t . A n i n h i b i t o r y s t i m u l u s i s a s t i m u l u s w h i c h d e v e l o p s t h e c a p a c i t y t o d e c r e a s e r e s p o n d i n g b e l o w t h e l e v e l o c c u r r i n g w h e n t h a t s t i m u l u s i s a b s e n t . T h e t e r m e x c i t a t o r y d i m e n s i o n a l c o n t r o l i s a p p l i e d w h e n new s t i m u l u s v a l u e s t h a t l i e a t p r o g r e s s i v e l y g r e a t e r d i s t a n c e s 3 along a specific dimension from an excitatory stimulus, produce a graded decremental effect of responding. The term inhibitory dimensional control i s used when stimulus values that l i e at progressively greater distances along a specific dimension from an inhibitory stimulus, produce a graded incremental effect on responding. Hearst et al's definition of stimulus control makes clear the rela-tionship between stimulus control and the traditional concepts of discrim-ination and generalization. Specific stimulus control i s analogous to d i s c r i -mination, while dimensional stimulus control is like stimulus generalization. There i s an advantage i n using the term stimulus control in description rather than the term discrimination and generalization because stimulus control merely describes empirical observations. Discrimination and generalization, on the other hand, describe processes and are often used as explanatory concepts. While the terms discrimination and generalization are used in this paper, they refer to specific stimulus control and dimensional control respectively. The experiment by Jenkins and Harrison (1960) provides a good i l l u s -tration of both excitatory control by a specific stimulus and excitatory dimensional control. Pigeons were reinforced for pecking i n the presence of 1000 cps tone on a variable interval (VI) 20 seconds schedule of re-inforcement. This nondifferential procedure failed to produce either specific excitatory control or dimensional excitatory control. The general-ization gradient was f l a t for a l l values along the auditory frequency dimension. As well, there was no difference in response strength when the tone was present as compared to when i t was absent. Another group of pigeons was given differential reinforcement: the 1000 cps tone was 4 c o r r e l a t e d with VI 20 seconds schedule of reinforcement and absence of tone was c o r r e l a t e d with nonreinforcement. The subsequently obtained g e n e r a l i z a t i o n gradient ind ica ted that both s p e c i f i c e x c i t a t o r y c o n t r o l and dimensional e x c i t a t o r y c o n t r o l had been e s tab l i shed . Response s trength i n the presence of the tone was above the l e v e l occurr ing when the tone was absent, i n d i c a t i n g s p e c i f i c e x c i t a t o r y c o n t r o l . Other tona l frequen-c i e s that l i e at progres s ive ly greater d is tances from the 1000 cps tone produced a graded decremental e f fec t on responding, i n d i c a t i n g that dimensional e x c i t a t o r y c o n t r o l had also been e s tab l i shed . The l i t e r a t u r e concerning the establishment of st imulus c o n t r o l and the v a r i a b l e s which a f f e c t st imulus c o n t r o l has been reviewed by Terrace (1966) and Nevin (1973). One of the c h a r a c t e r i s t i c features of many c h i l d r e n diagnosed as a u t i s t i c i s t h e i r unrespons iv i ty to v i s u a l as w e l l as audi tory s t i m u l i i n the absence of any observable sensory d e f i c i t . As a r e s u l t of t h i s , a great dea l of research has been done on d i s c r i m i n a t i o n l e a r n i n g i n a u t i s t i c c h i l d r e n . In genera l , the data suggest that there i s impaired v i s u a l d i s c r i m i n a t i o n i n a u t i s t i c c h i l d r e n . Hermelin and O'Connor (1965, Expt . 1) tested twenty c h i l d r e n between the ages of 7 years and 14 years 6 months, a l l of whom had been diagnosed as a u t i s t i c according to the Creak (1961) behav iora l d iagnos t i c l i s t . H a l f of the c h i l d r e n were res idents i n a h o s p i t a l f or chi ldhood psychot ics and the re s t came from four d i f f e r e n t mental d e f i c i e n c y i n s t i t u t i o n s . On the bas i s of t h e i r scores on the Peabody Vocabulary T e s t , which i s a tes t r e q u i r i n g the c h i l d to i d e n t i f y an object from a d i s p l a y of four adjacent 5 p i c t u r e s , the subjects were subdivided in to two groups of t en , one group c o n s i s t i n g of those who had obtained a minimum v e r b a l score of Mental Age (M.A.) 2 years 6 months and another group c o n s i s t i n g of c h i l d r e n whose scores were below M.A. 2 years 6 months. I t was assumed that t h i s sub-d i v i s i o n r e f l e c t e d the l e v e l of the c h i l d r e n ' s v e r b a l behavior . The a u t i s t i c c h i l d r e n were tested for in tra-d imens ion d i s c r i m i n a t i o n on four dimensions: albedo, s i z e , shape and d i r e c t i o n . For each of the dimensions, two examples of the s t i m u l i were presented. Thus, subjects were presented wi th a b lack and white square and a b lack and white apple for albedo; a l a r g e and small c i r c l e and a l a r g e and small b a l l for s i z e ; a t r i a n g l e with s t r a i g h t and curved s ides and toy houses with roofs of the same shape for shape; and a v e r t i c a l and h o r i z o n t a l l i n e and a man standing or l y i n g , f o r d i r e c t i o n . The st imulus cards were p laced over boxes, and the "correct" box had a candy hidden under i t . The subject was rewarded with the candy i f he pointed to or l i f t e d the correc t box. The r e s u l t s ind ica ted that c h i l d r e n who scored higher i n the v e r b a l t es t d i d be t ter on a l l in tra-d imens ion d i s c r i m i n a t i o n tasks than c h i l d r e n who had low scores . However, Hermelin and O'Connor suggested that the d i f f erence between the two groups of subjects was not simply due to the f a c t that the re levant cues could be named by the speaking group. Many of them could not name the re levant cue. I t i s p o s s i b l e that the v e r b a l i n s t r u c t i o n s given were too d i f f i c u l t f or the nonspeaking a u t i s t i c c h i l d r e n to fo l l ow , or a l t e r n a t i v e l y , they may have been unable to d i s c r i m i n a t e between s t i m u l i . There was a lso a s i g n i f i c a n t d i f f e r e n c e i n the ease wi th which sub-j e c t s acquired the d i f f e r e n t in tra-d imens ion d i s c r i m i n a t i o n . A l l subjects 6 took the l ea s t number of t r i a l s to acquire d i s c r i m i n a t i o n of s i z e . An increas ing number of t r i a l s were taken to acquire d i s c r i m i n a t i o n for the dimensions of albedo, shape and d i r e c t i o n . I t i s unfortunate that the authors d i d not inc lude a group of normal c h i l d r e n , or p r e f e r a b l y , s evera l groups of normal c h i l d r e n of d i f f e r e n t age groups as c o n t r o l s . I t i s pos s ib l e that the a u t i s t i c c h i l d r e n are comparable to young normal c h i l d r e n i n t h e i r a b i l i t y to acquire in tra -d imens iona l d i s c r i m i n a t i o n . Without a c o n t r o l group, one cannot be sure i f the d i f f i c u l t y i n d i s c r i m i n a t i n g shape, and e s p e c i a l l y d i r e c t i o n , i s a unique and s p e c i f i c problem of a u t i s t i c c h i l d r e n . A more s i g n i f i c a n t problem perhaps, i s that i n many of the s tudies conducted by Hermelin and O'Connor, subjects were not presented wi th a standard st imulus which ind ica ted the correc t s t imulus . Successful d i s -c r i m i n a t i o n was dependent not only on the subjec t ' s a b i l i t y to detect d i f -ferences between s t i m u l i presented, but a l so on h i s a b i l i t y to r e c a l l the consequences of h i s previous response. As such, the v a l i d i t y of these studies of simple d i s c r i m i n a t i o n a b i l i t y i s quest ionable . Over and Over (1967) have pointed out that experimental r e s u l t s such as those of Rudel and Teuber (1963), i n which young c h i l d r e n were found to have d i f f i c u l t i e s i n d i s c r i m i n a t i n g between obl ique l i n e s , may not have been due to poor d i s -c r i m i n a t i o n a b i l i t y . Rather, i t may have been caused by . the subjec t ' s i n a b i l i t y to remember from t r i a l to t r i a l what the correc t st imulus was. T h i s c r i t i -cism a l so app l i e s to the r e s u l t s obtained by Hermelin and O'Connor. Over and Over (1967) presented two l i n e s to 16 subjects between the ages of 5 years 6 months and 6 years and 6 months. Under the "detection" 7 c o n d i t i o n , the two l i n e s were of the same o r i e n t a t i o n on h a l f of the t r i a l s , and were d i f f e r e n t l y or iented on the other h a l f of the t r i a l s . The c h i l d was requ ired to judge whether the l i n e s were of the same or d i f f e r e n t o r i e n t a t i o n . Under the "recogni t ion" c o n d i t i o n the two l i n e s always d i f f e r e d i n o r i e n t a t i o n . The c h i l d was t o l d that s e l e c t i n g one of the l i n e s would always be "r ight" and s e l e c t i n g the other would be "wrong", and that h i s task was to i n d i c a t e the "r ight" l i n e on each t r i a l . I t was found that whi le only one subject f a i l e d to detect d i f f erences be-tween the l i n e s , seven out of s ix teen subjects f a i l e d to s e l ec t the "r ight" l i n e on the r e c o g n i t i o n task. I t i s important to keep t h i s r e s u l t i n mind i n the i n v e s t i g a t i o n of " d i s c r i m i n a t i o n a b i l i t y " . Notwithstanding the above c r i t i c i s m s , Hermelin and 0'Conner have obtained some i n t e r e s t i n g f i n d i n g s . In another experiment (1965, Expt . II) subjects were required to solve three d i s c r i m i n a t i o n problems. A l l sub-j e c t s were presented with two cardboard boxes. By l i f t i n g the "correct" box they would f i n d a candy. In task A the boxes were at d i f f e r e n t heights from the tab le at which the subject was seated. One box was on the table whi le the other box, a short d i s tance away from the f i r s t one, was on a small stand 12 inches above the top of the t a b l e . For h a l f of the subjects the "correct" box was the one on the t a b l e , and for the other h a l f of the subjec t s , i t was the one on the stand. In task B the boxes were at the same height but one box had an arrow painted on i t , p o i n t i n g e i t h e r up or down for d i f f e r e n t subjec t s . The c o r r e c t box i n t h i s case was the one wi th the arrow. In task C the boxes were again at the same height but t h i s time both boxes had an arrow. The arrows were p o i n t i n g i n opposite 8 d i r e c t i o n s , one pointed v e r t i c a l l y upward and the other downward. The con-s i s t e n t choice of e i ther the upward or downward p o i n t i n g arrow was r e i n -forced . Presumably task A could be solved i f subjects u t i l i z e d the k i n -es thet ic or v i s u o - s p a t i a l cues prov ided . Task B could be solved by d i s t i n g u i s h i n g between the t o t a l amount of l i g h t r e f l e c t e d from the surface of the the two st imulus objec t s , or simply by d i s t i n g u i s h i n g between the presence or absence of the arrow. The t h i r d task required subjects to perce ive d i f f e r i n g o r i e n t a t i o n s of otherwise i d e n t i c a l f i g u r e s . The subjects were twenty a u t i s t i c c h i l d r e n and ten subnormals. The a u t i s t i c c h i l d r e n were the same as those who had p a r t i c i p a t e d i n the previous study (Hermelin and O'Connor, 1965, Expt . I ) . None of the subnormal con-t r o l s had any p o s i t i v e scores on any of the items of Creak's (1961) d i a g -n o s t i c l i s t f or a u t i s t i c c h i l d r e n . The subnormals were se lected from four d i f f e r e n t mental i n s t i t u t i o n s and were matched wi th the a u t i s t i c sub-j e c t s on the scores obtained on the Peabody Vocabulary T e s t . An a n a l y s i s of var iance comparing the a u t i s t i c speaking, a u t i s t i c nonspeaking and subnormal c h i l d r e n showed a h i g h l y s i g n i f i c a n t i n t e r a c t i o n between groups and treatments. The subnormal c h i l d r e n showed no d i f f e r e n c e i n the number of t r i a l s needed to reach c r i t e r i a i n any of the three problems. For the speaking a u t i s t i c c h i l d r e n , a s i g n i f i c a n t l y greater number of t r i a l s was needed to reach the c r i t e r i o n on task C than on task A but task B d i d not d i f f e r s i g n i f i c a n t l y from e i t h e r A or C. The non-speaking a u t i s t i c c h i l d r e n required an i n c r e a s i n g number of t r i a l s to reach c r i t e r i o n from tasks A through C . They showed no d i f f e r e n c e from the other groups i n l e a r n i n g task A , but a l l ten subjects f a i l e d to l e a r n task C i n 9 s i x t y t r i a l s . In any case, the d i f f erence between the speaking a u t i s t i c c h i l d r e n and the subnormals was s t a t i s t i c a l l y n o n s i g n i f i c a n t . There was a marked and h i g h l y s i g n i f i c a n t d i f f e r e n c e between the nonspeaking a u t i s t i c c h i l d r e n and the other two groups i n both tasks B and C . The authors po int out , however, that although i n a b i l i t y to d i s c r i m i n a t e be-tween s t i m u l i of d i f f e r i n g o r i e n t a t i o n s i s assoc iated wi th the absence of speech, a causa l r e l a t i o n s h i p should not be assumed. For a fur ther d i s -cuss ion on the language hypothesis of autism, r e f e r to the Appendix. In an attempt to exp la in the above f i n d i n g s , Hermelin and O'Connor propose that there i s a tendency for a u t i s t i c c h i l d r e n to r e l y heav i ly on information from proximal receptors , i . e . . k i n e s t h e t i c cues. When the boxes were i n d i f f e r e n t p o s i t i o n s , d i s c r i m i n a t i o n was f a c i l i t a t e d by the upward or s t r a i g h t ahead reaching movements. When these k i n e s t h e t i c cues were e l iminated and success on the task depended s o l e l y on v i s u a l cues, the performance of the a u t i s t i c c h i l d r e n dropped markedly and i n some cases d i s c r i m i n a t i o n was never acqu ired . Thi s was evident i n task C . I t i s p o s s i b l e that the above r e s u l t s were obtained simply because of the d i f f i c u l t y a u t i s t i c c h i l d r e n have i n d i s c r i m i n a t i n g d i r e c t i o n a l cues, and not because of t h e i r tendency to u t i l i z e t a c t u a l and motor cues at the expense of v i s u a l and audi tory cues. In the previous study (Hermelin and O'Connor, 1965, Expt . I ) , i t was shown that a u t i s t i c c h i l d r e n had d i f f i c u l t y d i s c r i m i n a t i n g between a h o r i z o n t a l and v e r t i c a l l i n e and a standing and l y i n g man. S i m i l a r l y , i n task C (Hermelin and O'Connor, 1965, Expt . I I ) , the s t i m u l i cons i s ted of i n v e r s e l y or iented f i g u r e s : an arrow p o i n t i n g upward or downward. However, the f ind ings of another study ( F r i t h and Hermel in , 1969) 10 a l so seem to suggest that the s t r a t e g i e s most e f f i c i e n t l y used by a u t i s t i c c h i l d r e n are those based on immediate feedback from k i n e s t h e t i c cues. The procedure involved i n the study, however, was cons iderably d i f f e r e n t from the procedure of the experiments mentioned above. The subjects were p r e -sented wi th more of a problem - s o l v i n g s i t u a t i o n rather than a simple d i s c r i m i n a t i o n task. The subjects were given f i v e sets of cards , each set conta in ing s i x c a r d s , and they were requ ired to arrange each set of cards i n the proper order . A l l cards had p i c t u r e s p r i n t e d on them so that t h e i r v e r t i c a l o r i e n t a t i o n was apparent. Cards i n set A and A ' had s t r a i g h t edges and the correc t arrangement of these sets would al low for a continuous l i n e to form through the se t . Sets B and B' a l so had l i n e s on each segment which could be arranged i n such a way as to form an unbroken l i n e through each set . In a d d i t i o n , they had j igsaw-puzz le type edges, each segment i n t e r l o c k i n g with the adjacent one. Set C resembled B and B' i n that i t had i n t e r l o c k i n g edges but i t d i d not have a l i n e running through i t . In order for the c h i l d to arrange the cards i n the predetermined order , i t was necessary for him to adopt d i f f e r e n t kinds of s trategy according to the type of informat ion or cues provided. An exc lus ive use of v i s u a l cues would be the optimal s trategy f o r sets A and A ' . Sets B and B' had the same v i s u a l cues as i n the previous set although the c h i l d could a l so r e l y on the t a c t i l e feedback of the i n t e r l o c k i n g edges of the adjacent cards . A minimum of v i s u a l information was given i n set C , as the c h i l d had only immediate k i n e s t h e t i c feedback to depend on. According to the authors , the matching of the i n t e r l o c k i n g edges was too d i f f i c u l t f or the c h i l d to r e l y on v i s u a l scanning of the edges. Thus, whi le a s trategy of us ing 11 v i s u a l cues could have played a r o l e i n a l l tasks , they were maximized i n set A and minimized i n set C . The subjects were 20 a u t i s t i c , 20 subnormal and 20 normal c h i l d r e n . The a u t i s t i c c h i l d r e n were se lec ted according to p s y c h i a t r i c d i a g n o s i s , which i n a l l cases inc luded onset before two years of age, absence or im-pairment of speech, and "stereotyped and mannerist ic" behavior . A l l the subnormal c h i l d r e n had I . Q . ' s below 50 and were free from a u t i s t i c symptoms. The c h i l d r e n from a l l three groups were matched on t h e i r l e v e l of p e r f o r -mance on the F r o s t i g Test of V i s u a l Percept ion . T h i s tes t requ ired the c h i l d to draw a p e n c i l l i n e between two p r i n t e d l i n e s and to connect dots with a s t r a i g h t l i n e . The ages of the c h i l d r e n were between s i x and f i f t e e n years for the a u t i s t i c group, fourteen years to seventeen years seven months for the subnormal group and three years and nine months to s i x years and s i x months for the normal group. The r e s u l t s i n d i c a t e d tha t , wi th the exception of the a u t i s t i c c h i l d r e n who scored very low on the F r o s t i g Test of V i s u a l Percept ion , a l l of the c h i l d r e n performed best on the task depending most c l e a r l y on a v i s u a l s trategy (set A ) , and worst on the task which provided minimal v i s u a l i n -formation (set C ) . In c o n t r a s t , the a u t i s t i c c h i l d r e n who scored very low on the F r o s t i g Tes t , performed be t t er on set C than on set A , although the d i f f e r e n c e was not s i g n i f i c a n t . The p r o v i s i o n of v i s u a l informat ion d i d not seem to have any f a c i l i t a t i n g e f f e c t on the performance of the more regressed a u t i s t i c c h i l d r e n . The authors , however, d i d not i n d i c a t e the number of e rrors made by the respec t ive groups on set C. While the a u t i s t i c c h i l d r e n who scored very low on the F r o s t i g Test may have done be t t er on 12 set C than on sets A or B, i t i s pos s ib l e that the number of e rrors they made on set C was higher than the number of e r r o r s made by the other groups on the same se t . I f t h i s was the case, i t would be erroneous to i n f e r a predominance of proximal receptors i n a u t i s t i c c h i l d r e n . Rather , the r e s u l t s could be a r e f l e c t i o n of the general "low l e v e l of c o g n i t i v e funct ion" i n the a u t i s t i c subjec t s , e s p e c i a l l y s ince the tendency to r e l y on motor and t a c t i l e cues was found only i n the more regressed a u t i s t i c c h i l d r e n . There i s some evidence which suggests that the impaired v i s u a l d i s -c r i m i n a t i o n of a u t i s t i c c h i l d r e n i s accompanied by an i n a b i l i t y to attend to s t i m u l i f or an extended per iod of t ime. Hermelin and O'Conno.r (1967) have examined the v i s u a l a c t i v i t y and f i x a t i o n times of a u t i s t i c c h i l d r e n as compared to that of normal and subnormal c h i l d r e n . The procedure was one i n which the subject was required to p lace h i s head i n a viewing box. His responses to v i s u a l s t i m u l i d i sp layed i n the box were then observed. The measures taken were the t o t a l f i x a t i o n time on any one d i s p l a y and the amount of change i n the d i r e c t i o n of f i x a t i o n . I t was argued that d i f f erences i n f i x a t i o n time could p o s s i b l y lead to a d i f f e r e n t i a l amount of information y i e lded for the dimensions of (a) i d e n t i t y , (b) s i z e , (c) c o l o u r , (d) br ightness , (e) p a t t e r n , (f) complexity , and (g) meaningfulness. For each dimension, a p a i r of cards was presented, e _ . £ . , two white cards for i d e n t i t y ; two blue cards of d i f f e r e n t s i z e s ; a red and b lack card; e tc . Perceptual a c t i v i t y was measured by comparing v i s u a l i n s p e c t i o n time for the two s imultaneously presented d i s p l a y s . The a u t i s t i c subjects were chosen from two h o s p i t a l s and a s p e c i a l 13 schoo l , and each subject had been diagnosed by p s y c h i a t r i s t s according to the c r i t e r i a developed by Creak (1961). Hal f of the subjects had no speech and none, of them had any obvious sensory or motor defec t s . The normal c h i l d r e n were from a nursery school i n London, whi le the subnormals were chosen from a mental de f i c i ency h o s p i t a l . The mean ages for the three groups were: 5 years 4 months for the c o n t r o l (range 4 years and 3 months to 6 years and 1 month); 14 years 4 months for the subnormals (range 10 years and 9 months to 17 years and 7 months); and 11 years 4 months for the a u t i s t i c c h i l d r e n (range 7 years to 18 years and 11 months). Hermelin and O'Connor found that non-d irec ted gazing increased w i t h i n each 30 second per iod for a l l groups, but the a u t i s t i c group had lower f i x a t i o n scores than the other two groups. While the normals made frequent b r i e f glances at the d i s p l a y cards , the subnormal and a u t i s t i c c h i l d r e n achieved t h e i r f i x a t i o n scores by uninterrupted f i x a t i o n , although the a u t i s t i c c h i l d r e n looked at each card for a b r i e f e r time per iod than the subnormals. In terms of perceptual a c t i v i t y , then, there seems to be d i f ferences between a u t i s t i c and c h i l d r e n i n the other two groups, but the r e l a t i o n s h i p i s unc l ear . V i s u a l i n s p e c t i o n time i s not a r e l i a b l e i n d i c a t o r of the i n d i v i d u a l ' s a b i l i t y to perce ive d i f f e r e n c e s . While d i f -ferences i n v i s u a l in spec t ion time u s u a l l y i n d i c a t e that the i n d i v i d u a l has perce ived d i f ferences between s t i m u l i , one cannot i n f e r that d i f f erences were not perceived by the i n d i v i d u a l when the v i s u a l in spec t ion time for two d i f f e r e n t s t i m u l i are the same. For s i z e , br ightness and complexity, the scores w i t h i n p a i r s of s t i m u l i were the same. However, t h i s does not mean that d i f f erences were not perce ived as the a u t i s t i c c h i l d r e n were able 14 to acquire s i z e and b r i g h t n e s s d i s c r i m i n a t i o n i n s t u d i e s when an operant response was r e q u i r e d (Hermelin and O'Conner, 1965). The hypothesis that there i s a predominance of proximal r e c e p t o r s over d i s t a n c e receptors i n a u t i s t i c c h i l d r e n was incorporated by Hermelin and O'Connor i n t o the l a r g e r t h e o r e t i c a l framework of h i e r a r c h i c a l organ-i z a t i o n of sensory channels. This theory suggests that i n f o r m a t i o n v i a c e r t a i n sensory channels may be responded to more r e a d i l y than data pro-v i d e d from other channels. The concept of h i e r a r c h i c a l s t r u c t u r e of sensory systems has been connected w i t h the developmental process i n young c h i l d r e n . Some i n v e s t i g a t o r s of normal c h i l d r e n ( B i r c h , 1962; Zaporozhets, 1961) have formed the hypothesis of a gradual developmental change from proximal to d i s t a n c e receptor dominance. The concept of r e l a t i v e sensory dominance has a l s o been used f o r i n v e s t i g a t i n g responses to environmental s t i m u l a t i o n i n s c hizophrenic c h i l d r e n (Goldfarb, 1956). Goldfarb suggested that s c h i z o p h r e n i c c h i l d r e n make contact w i t h t h e i r environment through proximal r a t h e r than d i s t a n c e receptor channels. I n adopting the concept of h i e r -a r c h i c a l sensory o r g a n i z a t i o n i n t h e i r i n v e s t i g a t i o n of a u t i s t i c c h i l d r e n , Hermelin and O'Connor(1964) suggest that there i s a r e t a r d a t i o n of develop-mental processes i n a u t i s t i c c h i l d r e n a t the stage of proximal receptor dominance. Hermelin and O'Connor (1964) conducted an experiment i n order to e s t a b l i s h the r e l a t i v e responsiveness of a u t i s t i c c h i l d r e n to s t i m u l i i n d i f f e r e n t sensory m o d a l i t i e s . V i s u a l , a u d i t o r y , and t a c t i l e s t i m u l i were used. Subjects were t e s t e d i n d i v i d u a l l y w h i l e seated at a t a b l e opposite the experimenter w i t h the apparatus on the t a b l e between them. L i g h t s were 15 placed on e i t h e r end of the d i s p l a y panel and buzzers were mounted behind the screen out of s i g h t of the s u b j e c t . The l i g h t s and buzzers were con-t r o l l e d by the experimenter. For the t a c t i l e s t i m u l u s , pieces of s t r i n g were l i g h t l y t i e d around the subject's ankles. The experimenter, by p u l l i n g the ends of the s t r i n g , could g i v e a l i g h t tug on e i t h e r ankle. I n i t i a l l y , s t i m u l i were presented s i n g l y , i n succession. Subjects were t r a i n e d to l i f t the l i d of a box on the same si d e from which the stimulus came. I n s i d e the c o r r e c t box was a candy. In the f o l l o w i n g experimental s e s s i o n , p a i r s of s t i m u l i were presented simultaneously w i t h each coming from a d i f f e r e n t d i r e c t i o n . For example, a l i g h t might appear on the l e f t and the sound of the buzzer from the r i g h t , or any combination of the three d i f f e r e n t s t i m u l i counterbalancing f o r p o s i t i o n . During these t r i a l s there was no i n c o r r e c t response; there was a candy i n both the r i g h t and l e f t boxes. I t was assumed that the subject's choice of boxes over t r i a l s would r e v e a l h i s p r e f e r r e d modality, thus demonstrating h i s r e l a t i v e responsiveness to the three d i f f e r e n t sensory m o d a l i t i e s . The subjects were a group of ten subnormal c h i l d r e n and a group of ten a u t i s t i c c h i l d r e n matched f o r c h r o n o l o g i c a l age, sex and, as f a r as p o s s i b l e , I.Q. The mean age of the a u t i s t i c and the c o n t r o l group was 12 years, ranging from 8 years 6 months to 16 years. The mean I.Q. f o r the a u t i s t i c c h i l d r e n was 40 p o i n t s ranging from 28 to 55 p o i n t s , and that f o r c o n t r o l s was 43 p o i n t s w i t h a range from 30 to 56. No c h i l d was s e l e c t e d f o r the a u t i s t i c group unless he had at l e a s t three of the symptoms l i s t e d by Creak (1961). I t should be noted that c h i l d r e n w i t h evidence of c e n t r a l nervous system damage were included i n both the experimental and 16 c o n t r o l groups, although there was no d i f f e r e n c e i n the frequency of such c l i n i c a l s igns between the groups. Hermelin and 0'.Connor found that most s u b j e c t s , i r r e s p e c t i v e of d i a g n o s t i c c r i t e r i a , responded to l i g h t whenever a v i s u a l stimulus was a component i n the combination of s i g n a l s . However, when sound was combined w i t h a t a c t i l e s t i m u l u s , most subnormals responded to sound, w h i l e the a u t i s t i c c h i l d r e n responded to the tug at the ankle. When only a u d i t o r y and v i s u a l s t i m u l i a t d i f f e r i n g i n t e n s i t i e s were used, a l l groups showed an increase i n sound o r i e n t e d responses f o r the loud n o i s e / s o f t l i g h t combination, but the scores of the a u t i s t i c c h i l d r e n remained more evenly d i s t r i b u t e d under a l l m odality and i n t e n s i t y combinations than those of subnormals. This r e s u l t was taken as evidence that the responses of a u t i s t i c c h i l d r e n are determined more by the p o s i t i o n i n g of the s t i m u l u s source e i t h e r to the r i g h t or l e f t , than by d i f f e r e n t i n t e n s i t i e s or d i f f e r e n t stimulus m o d a l i t i e s . There i s , however, l i t t l e j u s t i f i c a t i o n f o r t h i s c o n c l u s i o n as i t i s h i g h l y p o s s i b l e that the r e s u l t s are an a r t i f a c t of the design used. I t was assumed that the l i g h t s , the buzzer and the tug at the ankle were the s a l i e n t cues i n the experiment. However, f o r some of the s u b j e c t s , the r e l a t i o n s h i p between the p a r t i c u l a r box chosen and the candy that was found i n i t , may have been the determining f a c t o r . As there were no i n c o r r e c t responses, some su b j e c t s may have p e r s i s t e d i n responding to the same box throughout the experimental s e s s i o n r e g a r d l e s s of the i n t e n s i t y or modality of the s t i m u l i combination presented. Thus, motivation. and/or suscep-t i b i l i t y to c o n d i t i o n i n g may have been the f a c t o r s i n v o l v e d , r a t h e r than the predominance of p o s i t i o n responses i n a u t i s t i c c h i l d r e n . More important, 17 perhaps, Is the finding that the relative dominance of the visual channel seems to have been equally established in the autistic as well as in the subnormal children. If indeed the proximal receptors are dominant in autistic children as Hermelin and O'Connor claimed, then autistic children should have responded more to the tactile stimulus than to either visual or auditory stimuli. Briefly, the work of Hermelin and O'Connor can be summarized as follows. The longer time spent in undirected gazing by autistic subjects (Hermelin and O'Connor, 1967), suggests that they "attend" to a stimulus display for a shorter time than normal. Presumably, this could mean that autistics gain less information from the same stimulus than normals. However, whether or not the 1965 experiments indicate impaired visual discrimination is questionable as there was no stan-dard stimulus with which the choice stimuli could be compared across trials; poor performance could be due to poor recall of the correct stimulus rather than an inability to discriminate differences between stimuli. Poor performance of autistic children in tasks involving primarily visual cues (Frith and Hermelin, 1969) is not sufficient evidence of their dependence on tactile and motor cues. As the subjects were described as having a "low level of cognitive functioning", it is reasonable to assume that trial-and-error is their favoured strategy. Assuming that a trial-and-error strategy is used for all sets of cards, the probability of making errors in arranging cards with straight edges (set A, maximum visual cues) would be greater than in other sets simply because each segment in set A would fit adjacent to every other segment in the set. Finally, the results of 18 the 1964 study (Hermelin and O'Connor) f a i l e d to support the hypothesis of proximal receptor dominance. The r e l a t i v e dominance of the v i s u a l channels seemed to have been equal ly e s tab l i shed i n the a u t i s t i c s as w e l l as i n the subnormals. While Hermelin and O'Connor and assoc iates have attempted to exp la in the apparent unrespons iv i ty of a u t i s t i c c h i l d r e n to v i s u a l and audi tory s t i m u l i i n terms of a sensory h i e r a r c h i c a l theory charac ter i zed by a p r e -dominance of the motor-k ines thet ic system over that of the v i s u o - a u d i t o r y mechanism, Lovaas and h i s assoc iates (Lovaas, Schriebman, Koegel and Rehm, 1971) have argued i n favour of a s e l e c t i v e a t t e n t i o n hypothes is . They proposed that the problem with a u t i s t i c c h i l d r e n i s one of st imulus s e l e c t i v i t y . Contrary to the f ind ings of Hermelin and O'Connor (1964, 1965), t h e i r data have f a i l e d to support the not ion that any one modal i ty i s impaired i n a u t i s t i c c h i l d r e n , or that a p a r t i c u l a r modality i s the "preferred" modal i ty . The germinal ideas under ly ing a t t e n t i o n theories of d i s c r i m i n a t i o n l earn ing were expressed by Lashley and Kechevsky during the 1930's. A c -cording to L a s h l e y , during d i s c r i m i n a t i o n l e a r n i n g , "a d e f i n i t e a t t r i b u t e of the st imulus i s ' abs trac ted ' and forms the bas i s of r e a c t i o n " (Lashley , 1938, p . 81). Since Lash ley , most a t t e n t i o n theories of d i s c r i m i n a t i o n assume that l earn ing occurs i n two stages. For example, Zeaman and House (1963) theor ized that d i s c r i m i n a t i o n l earn ing requires f i r s t a c e n t r a l mediating response i d e n t i f i e d with a t t e n t i o n to the re levant st imulus dimension, and, second, an instrumental response of approach to the ap-p r o p r i a t e va lue . A l l a t t e n t i o n a l theor ies assume that the var ious a t t r i b u t e s 19 of objects are not equal ly attended to . Some dimensions are v a s t l y more s a l i e n t than others , and those dimensions tend to dominate performance. S e l e c t i v e a t t e n t i o n r e f e r s to the process i n which an organism, when presented with m u l t i p l e , redundant cues, attends to or comes under the c o n t r o l o f , only a p o r t i o n of the a v a i l a b l e s t i m u l i (Terrace , 1966; Trabasso and Bower, 1968). There i s general agreement that i n d i v i d u a l subjects i n animal ex-periments of ten attend to only one of the re levant cues. The se lec ted cue, however, may be d i f f e r e n t for d i f f e r e n t subjects of c lasses of sub-j e c t s (Jones, 1954; Reynolds, 1961; Sutherland and Holgate , 1966). Reynolds (1961), f or example, t r a i n e d pigeons on a success ive d i s c r i m i n a t i o n i n which a'white t r i a n g l e on red background was assoc iated wi th reinforcement , and a white c i r c l e on a green background was assoc iated wi th e x t i n c t i o n . A f t e r t r a i n i n g , the components of the s t i m u l i were presented seperate ly during an e x t i n c t i o n sess ion . The r e s u l t s i n d i c a t e d that both aspects of the st imulus assoc iated with e x t i n c t i o n acquired c o n t r o l over not r e -sponding; ne i ther pigeon responded to e i t h e r the green background or the white c i r c l e . D i f f e r e n t aspects of the st imulus assoc iated wi th r e i n -forcement acquired c o n t r o l over responding i n d i f f e r e n t subjec t s . One pigeon responded only when the red background was presented, and the other responded only when the white t r i a n g l e was presented. I t should be noted that s e l e c t i v e a t t e n t i o n i s not always of the i d i o s y n c r a t i c type demonstrated i n Reynolds' (1961);study. There i s a l so systematic s e l e c t i v e a t t e n t i o n which has been assoc iated wi th the not ion of an "attending hierachy". For example, Newman (1965) found that when 20 the stimulus associated with reinforcement is a vertical l i n e on red back-ground and the stimulus associated with extinction i s a horizontal line on a green background, pigeons always responded to the colour rather than the line orientation. As well, i t should be noted that selective attention does not always occur with redundant stimuli. Butter (1963) for example, reinforced pigeons for responding to a band of light whose wavelength and orientation could be Simulataneously varied. During training the light was 550 mu and in a vertical position. In the subsequent gen-eralization test, Butter found that the responses of pigeons had been brought under the control of both the wavelength and-orientation. In an attempt to explain stimulus selectivity, Sutherland and Mackintosh have developed a model which incorporates the idea of a stimulus analysing mechanism (Sutherland, 1963; Mackintosh, 1965). According to this account, in acquiring discrimination a subject has to learn to switch-in the appropriate stimulus analyser and then to attach the appropriate instru-mental response to the outputs from this analyser. The stimulus that the subject responds to is determined by the reinforcement contingencies. Alternatively, stimulus selectivity may be explained by Rescorla and Wagner's (1972) theory of stimulus blocking. Stimulus blocking is the result of the differential rate of learning of different cues iri a complex stimulus. If the rate of learning of one cue is faster than the rate of learning of the other cues, the faster learned cue blocks the learning of other cues. While both the analyzer theory and the stimulus blocking theory can account for the Newman type of result, and the Butter type of result, neither can apparently handle the Reynolds type of result. 21 According to Lovaas, the f a i l u r e of c o g n i t i v e , s o c i a l and emotional development i n a u t i s t i c c h i l d r e n i s due to d e f i c i e n c i e s i n a t t e n t i o n a l mechanism. This i n f e r e n c e was made on the b a s i s of the r e s u l t s obtained from the f o l l o w i n g experiment. Lovaas, B e r b e r i c h , P e r l o f f and Schaeffer (1966) presented both v e r b a l and v i s u a l cues to mute a u t i s t i c c h i l d r e n to f a c i l i t a t e t h e i r v e r b a l t r a i n i n g . The c h i l d could c l e a r l y see the teacher's face when she pronounced the v a r i o u s sounds, such as "mm" which has a u d i t o r y and v i s u a l cues q u i t e d i s t i n c t from "ah". When the v i s u a l cues a s s o c i a t e d w i t h the sound were removed, as when the teacher purposely covered her fa c e , the c h i l d ' s performance showed a marked d e c l i n e . The d i s t i n c t i o n was made between "nominal" stimulus which c o n s i s t e d of the t o t a l s et of the a v a i l a b l e elements, and " f u n c t i o n a l " stimulus which i s that part of the t o t a l stimulus which a c t u a l l y c o n t r o l l e d behavior. The authors' e x p l a n a t i o n of the marked d e c l i n e i n the c h i l d ' s performance f o l l o w i n g the removal of the v i s u a l cues was that the v i s u a l cues com-p r i s e d the f u n c t i o n a l component of the stimulus and consequently, i n i t s absence, performance could not be maintained at the same high l e v e l . In another study (Lovaas, Schriebman, Koegel and Rehm, 1971) sub j e c t s were r e i n f o r c e d f o r responding i n the presence of a stimulus d i s p l a y and were not r e i n f o r c e d f o r responding i n the absence of the d i s p l a y . The experimental set-up was very s i m i l a r to that of Hermelin and O'Connor's 1964 experiment. The subject was seated i n f r o n t of a t a b l e , on which a box, w i t h a 3 i n c h bar pro t r u d i n g from i t s f r o n t , had been placed. The box dispensed a candy each time the bar was pressed. Sound equipment and one-way v i s i o n screens connected the experimental room to an observation 22 room from which the experimenter controlled the various experimental pro-cedures. Three kinds of stimuli were employed: a visual stimulus, which consisted of a 150 W red floodlight mounted on the ceiling behind the subject; an auditory stimulus, consisting of white noise fed from a tape recorder into a speaker above the subject; and a tactile stimulus applied by forcing air into a blood pressure cuff fastened around the subject's l e f t calf. Subjects were trained to press the bar whenever the stimulus complex was presented. When the subject failed to give any evidence of decreased rate of responding during the interval between stimulus complex presentations, the experimenter would deliver a loud "no" over the inter-com contingent on such a response. After the child had been brought under the control of the stimulus complex, components of the stimulus r : complex were presented singly to assess which aspects of the stimulus complex had acquired control over the child's behavior. The subjects were made up of a group of autistic children, a group of retardates, and another of normal children. The mean chronological age was 7 years 2 months (range 4 to 10 years) for the autistic group, 8 years (range 7 to 10 years) for the retarded group, and 6 years 4 months (range 6 to 7 years 6 months) for the normal group. In general, there was a great deal of va r i a b i l i t y in the acquisition of the discrimination. It was reported that the normal subjects learned to respond to the stimulus complex and not to respond in i t s absence within a matter of minutes. The retarded subjects required, on the average, less than 30 minutes of training, while the autistic group required twice as many sessions as the retardates. In the second part of the experiment 2 3 there were s i g n i f i c a n t d i f f erences between groups i n the number of st imulus components which produced responding. A s t a t i s t i c a l a n a l y s i s of the data i n d i c a t e d that the a u t i s t i c s responded p r i m a r i l y to one s t imulus , re tardates to two and normals to a l l three components. The normals gave no evidence of a preference among the cues, or that they were s e l e c t i v e l y at tending to some cues and not to o thers . Of the f i v e a u t i s t i c c h i l d r e n tes ted , two responded p r i m a r i l y to v i s u a l cues and three to audi tory s t i m u l i . I t should be noted that the responses of the a u t i s t i c c h i l d r e n were weakest, and i n one case t o t a l l y absent, f o r the t a c t i l e s t imulus . These observat ions are the opposite of the f ind ings of Hermelin and O'Connor, and are i n d i r e c t c o n t r a d i c t i o n to t h e i r hypothesis of a predominance of proximal receptors i n a u t i s t i c c h i l d r e n . I f indeed there was a p r e -dominance of proximal receptors i n a u t i s t i c c h i l d r e n , as Hermelin and O'Connor had hypothesized, then the a u t i s t i c c h i l d r e n i n Lovaas et a l ' s study (1971) should have responded p r i m a r i l y to the t a c t i l e s t imulus . The g e n e r a l i z a b i l i t y of Lovaas et a l ' s f ind ings are somewhat l i m i t e d as the a u t i s t i c c h i l d r e n i n the study were extremely regressed. Four of the subjects were mute and gave only sporadic responses to the most elementary commands, , " s i t down", "come here". Three had e a r l y h i s -t o r i e s of suspected deafness, were i n p a t i e n t s , and, i n a l l l i k e l i h o o d , faced permanent h o s p i t a l i z a t i o n . Two of the subjects were not t o i l e t t ra ined and could not dress themselves. D i f f e r e n t r e s u l t s may have been obtained had the a u t i s t i c c h i l d r e n been l e s s regressed. Lovaas et a l i n t e r p r e t e d t h e i r r e s u l t s i n terms of nominal and func-t i o n a l cues ( i . e . , s e l e c t i v e a t t e n t i o n ) . They suggested that the a u t i s t i c 24 child's problem is "stimulus overselectivity", or the tendency to attend to only a small portion of a stimulus complex, and because he is rein-forced for responding to it , the subject does not broaden his learning to other relevant cues. Traditionally, the term stimulus selectivity is used to refer to the tendency to attend to or come under the control of only a portion of the stimulus array available, when the stimuli are multidimensional as in Reynolds' (1961) study, or when the stimuli are multimodal as in the study by Lavaas et al (1971). The concept of stimulus selectivity can be broadened to include steep generalization or dimensional gradients and the ability to discriminate between stimuli that lie close together on a specific dimension. Steep dimensional control gradients would be produced if a subject responds to a very small range of stimulus values that lie along a particular dimension, with maximum response strength occurring at that stimulus previously associated with reinforcement. Fine discriminations would indicate that the subject is being selective to the stimulus responded to. If the problem with autistic children is stimulus selectivity, then one would expect them to be able to discrim-inate small differences between stimuli, and that in a generalization test, the subsequent gradients produced would be steep. It is possible that the autistic child's obsessive desire to maintain sameness is due to extreme stimulus-selectivity or stimulus control. For example it has been observed by the present writer that in teaching the autistic child self-care skills, for example, tying shoelaces, it was necessary to adhere to the exact sequence of steps. Any change in the sequence of steps resulted 25 i n the c h i l d not completing the task. In the study by Lovaas et a l (1971), the a u t i s t i c c h i l d ' s d i f f e r e n t i a l response to the st imulus complex and elements of the st imulus presented seperate ly could be viewed as evidence of sharper st imulus c o n t r o l i n these subjects compared to the normal sub-j e c t s . In Hermelin and O'Connor's study (1964) i t was shown that the a u t i s t i c c h i l d r e n were unresponsive to the sound/ l i gh t combination and instead p e r s i s t e n t l y responded to the same box under which he found a candy. I t i s not unreasonable to argue that the c h i l d ' s behavior had been brought under the c o n t r o l of the box rather than the s i g n a l s . I t should be noted that whi le s e l e c t i v e a t t e n t i o n or st imulus c o n t r o l i s an important and necessary asset i n coping wi th the numerable and complex s t i m u l i that an i n d i v i d u a l i s confronted wi th d a i l y , the tendency to the extreme i s undes irab le . I t i s pos s ib l e that extreme st imulus s e l e c t i v i t y or st imulus c o n t r o l might contr ibute important ly to the a u t i s t i c c h i l d ' s f a i l u r e i n the a c q u i s i t i o n of new behav iora l topography, and,as s u c h , i t has s i g n i f i c a n t i m p l i c a t i o n s for the type of remedial program he should rece ive for the l earn ing of new s k i l l s . Purpose of Present Research The purpose of the present study was to provide a d d i t i o n a l data on st imulus c o n t r o l i n a u t i s t i c c h i l d r e n . During t r a i n i n g i n Experiment I , both a u t i s t i c and normal c h i l d r e n were examined for t h e i r ra te of a c q u i -s i t i o n of st imulus c o n t r o l . Subjects were presented wi th a v e r t i c a l l i n e and a l i n e t i l t e d at angle of 33 degrees from the v e r t i c a l and were r e i n -forced f o r responding to the v e r t i c a l l i n e . The number of t r i a l s taken to reach c r i t e r i o n were recorded. It should be noted that i n Hermelin 26 and O'Connor's (1965) experiment, the a u t i s t i c subjects had great d i f -f i c u l t y i n d i s c r i m i n a t i n g between a v e r t i c a l and h o r i z o n t a l l i n e . Fo l lowing t r a i n i n g i n Experiment I , and i n Experiment I I , subjects were given a g e n e r a l i z a t i o n tes t to determine the degree of c o n t r o l by the l i n e t i l t . The subsequent g e n e r a l i z a t i o n gradients provided data on dimensional st imulus c o n t r o l i n a u t i s t i c c h i l d r e n . Most of the s tudies on d i s c r i m i n a t i o n l e a r n i n g i n a u t i s t i c c h i l d r e n have neglected to look at dimensional c o n t r o l i n a u t i s t i c c h i l d r e n . As w e l l , i n part two of Experiment I , subjects were t r a i n e d to d i s c r i m i n a t e between a v e r t i c a l l i n e and l i n e s t i l t e d p r o g r e s s i v e l y c l o s e r to the v e r t i c a l . I f the a u t i s t i c c h i l d ' s problem i s "stimulus overse l ec t iv i ty ' ; as Lovaas et a l have suggested, then st imulus c o n t r o l by l i n e t i l t may be greater i n a u t i s t i c than i n c o n t r o l subjec t s , i . e . . , the a u t i s t i c subjects may be c o n t r o l l e d by dev ia t ions of l i n e o r i e n t a t i o n s from the v e r t i c a l to a greater degree than the c o n t r o l subjec t s . Experiment I I I was designed to tes t i f a u t i s t i c c h i l d r e n can l e a r n a mult id imensional d i s c r i m i n a t i o n . A u t i s t i c and c o n t r o l subjects were t r a i n e d to choose,from four comparison s t i m u l i that d i f f e r e d both i n shape and i n the presence or absence of a s t a r w i t h i n i t , one st imulus that matched the standard s t imulus . The a u t i s t i c subjects i n Lovaas et a l ' s study (1971) had great d i f f i c u l t y i n a c q u i r i n g d i s c r i m i n a t i o n of the complex s t imulus . For example, one a u t i s t i c c h i l d was run f o r a t o t a l of 5 sessions a week f o r three months and s t i l l responded l e s s than 80 percent of the time to complex s t imulus . While Lovaas et al_ i n -terpreted the data i n terms of st imulus s e l e c t i v i t y , i t i s pos s ib l e that 27 the r e s u l t s were produced as a r e s u l t of the a u t i s t i c subjects f a i l u r e to l e a r n mult id imens ional d i s c r i m i n a t i o n . 28 CHAPTER I I : EXPERIMENTS Three experiments were conducted to examine st imulus c o n t r o l i n a u t i s t i c s . In a l l three experiments a matching-to-sample procedure (Stoddard, 1 9 6 8 ) was employed and the same subjects were used. The purpose of Experiments I and II was to examine dimensional c o n t r o l by l i n e t i l t a f t er l i n e t i l t d i s c r i m i n a t i o n t r a i n i n g . The purpose of Experiment I I I was to examine a c q u i s i t i o n of mult id imensional d i s c r i m i n -a t i o n . Experiment I Subjects were t r a i n e d on a matching-to-sample procedure to d i s -cr iminate between a v e r t i c a l l i n e and a l i n e t i l t e d at 3 3 degrees from the v e r t i c a l . They were then given a g e n e r a l i z a t i o n tes t to determine the degree of c o n t r o l by l i n e t i l t . Fo l lowing the g e n e r a l i z a t i o n t e s t , subjects were t r a i n e d to d i s c r i m i n a t e between a v e r t i c a l l i n e and a l i n e t i l t e d progres s ive ly c l o s e r to the v e r t i c a l . Method Subjects The subjects were 6 to 9 year o ld boys. Three of the subjects were a u t i s t i c , and four were c o n t r o l subjec t s . 29 A u t i s t i c Subjects Subjects for the a u t i s t i c group were from L a u r e l House which i s located i n Vancouver at 1896 West 15th Avenue. L a u r e l House i s a government-subsidized home for c h i l d r e n wi th behavior d i s o r d e r s . I t accomodates about twelve to f i f t e e n c h i l d r e n . Most of the c h i l d r e n are i n res idence , whi le others are on a day program. There are twelve members on the s t a f f , i n c l u d i n g the secretary and the cook. Each s t a f f member i s respons ib le f o r only three c h i l d r e n during a work se s s ion . Behavior m o d i f i c a t i o n procedures (cf . A y l l o n and A z r i n , 1968) are used. S p e c i a l a t t e n t i o n i s devoted to the improvement of v e r b a l behavior . A c t i v i t i e s such as s k a t i n g , swimming and an afternoon at the gym are inc luded i n the program. The type of reinforcement used v a r i e s for d i f f e r e n t c h i l d r e n , but s o c i a l reinforcement i s used ex tens ive ly . A c h i l d i s g iven a s i x month t r i a l per iod on the program and i f , during t h i s t r i a l per iod no change i s observed, therapy i s d iscont inued and the c h i l d i s returned to h i s home. In comparison wi th some of the d e s c r i p t i o n s of a u t i s t i c c h i l d r e n i n the l i t e r a t u r e , the three a u t i s t i c subjects chosen for the study genera l ly d i d not possess extremely severe behavior d i s o r d e r s . However, they had a l l been diagnosed as a u t i s t i c by two or more p s y c h i a t r i s t s , d i d not su f fer any sor t of p h y s i c a l handicap or sensory d e f i c i t and had a l l been t o i l e t t r a i n e d . The ir ages were, SA 1:5 years 11 months; SA 2:9 years; SA 3:8 years 4 months. (The abbrev ia t ion SA w i l l be used to r e f e r to the subjects i n the a u t i s t i c group) . Only SA 3 was a res ident at the house. 30 Information about the subjec t s ' v e r b a l , perceptua l , motor and s o c i a l behavior was obtained from the t h e r a p i s t s i n charge, who had i n turn obtained the information from a quest ionnaire taken from a study by Wing (1968) on the handicaps of a u t i s t i c c h i l d r e n . Verba l Behavior: A l l three boys spoke i n t e l l i g i b l y . They spoke i n sentences of three words or longer and fol lowed simple i n s t r u c t i o n s given i n short sentences. SA 1 arid SA 2 a r t i c u l a t e d words very c l e a r l y , but SA 3 sometimes tended to produce d i s t o r t e d sounds; for example, he would say "boar" instead of " b a l l " . SA 1 and SA 3 sometimes engaged i n e c h o l a l i c speech. A l l three r a r e l y i n i t i a t e d or took an a c t i v e part i n conversat ion . V i s u a l and Perceptual Behavior: I t was d i f f i c u l t to achieve eye-contact wi th SA .1 and SA 2. A l l three subjects could place d i f f e r e n t objects in to t h e i r appropriate cutouts i n a board, a task very s i m i l a r to the Sequin Form Board u t i l i z e d by Hermelin and O'Connor (1965) i n t h e i r re search . The subjects responded c o r r e c t l y to the words up-down, i n - o u t , and over-under. However, they seemed to have d i f f i c u l t y i n l e f t - r i g h t o r i e n t a t i o n . Motor Behavior: Abnormal body movements were evident i n SA 1 and SA 2. SA 1 frequent ly walked on t i p - t o e s and often ran around and around i n a c i r c l e . SA 2 frequent ly he ld h i s hands near h i s eyes, tw i s t ing and turning h i s f i n g e r s . He would sometimes i n j u r e himself by scra tch ing and p i c k i n g at h i s hands and l egs . SA 3 seemed to d i s p l a y l e s s abnormal body movements although he tended to get over ly upset when not allowed h i s own way. For example, he would loud ly protes t i f he was not allowed to continue 31 c o l o u r i n g h i s book. Other abnormal body movements of a l l three subjects were repeated grimacing when exc i ted and, as i n the case of SA 1 and SA 3, f requent ly f l i n c h i n g unexpectedly. Work and S o c i a l Behavior: The c h i l d r e n ' s behavior was charac ter i zed by a d i s tan t and a loof manner; i n t e r a c t i o n wi th other c h i l d r e n whether at work or p l a y , was absent. A l l a c t i v i t i e s such as c o l o u r i n g , c u t t i n g up shapes from paper, put t ing away toys i n a box, e t c . , had to be super-v i s e d by an a d u l t , although t h i s was more marked i n SA 1 and SA 2 than SA 3. The above c h i l d r e n were chosen for t h i s study because they met with the d iagnos t i c c r i t e r i a of e a r l y chi ldhood autism as def ined i n the p r e -vious chapter . They were a l so chosen because they could fo l low simple i n s t r u c t i o n s . Contro l Subjects The subjects f o r the c o n t r o l group were c h i l d r e n from a p a r o c h i a l s choo l , The Holy T r i n i t y Elementary School , i n North Vancouver. They were four boys, two from Grade Two, and two from Grade Three. The ir ages were: SC 1:8 years 7 months; SC 2:8 years 8 months; SC 3:8 years 9 months; SC 4: 8 years 8 months. (The abbrev ia t ion SC w i l l be used to r e f e r to the subjects i n the c o n t r o l group.) The subjects i n the c o n t r o l group were free from a l l d iagnos t i c c h a r a c t e r i s t i c s of a u t i s t i c c h i l d r e n , and d i d not have any p h y s i c a l handicap or sensory d e f i c i t . They were rated by t h e i r teachers as average students . S t i m u l i Subjects rece ived t r a i n i n g and tes t t r i a l s on a matching-to-sample 32 procedure. The s t i m u l i cons i s ted of l i n e s of d i f f e r e n t o r i e n t a t i o n . The l i n e s were approximately 56 mm long by .5 mm wide and were drawn with a b l a c k f e l t pen on white cards 22.5 cm by 30.3 cm. The standard st imulus ( v e r t i c a l l i n e ) was drawn on the upper h a l f of a l l cards . The two comparison s t i m u l i were drawn on the lower h a l f of a l l cards . The com-par i son s t i m u l i always cons i s ted of a v e r t i c a l l i n e (which matched the standard) and a l i n e t i l t e d from the v e r t i c a l . To preclude p o s i t i o n d i s c r i m i n a t i o n , the p o s i t i o n of the v e r t i c a l and t i l t e d l i n e s were counter-balanced. The t i l t e d l i n e randomly appeared on the r ight -hand s ide of the card 50 percent of the time and on the l e f t s ide 50 percent of the time. The comparison s t i m u l i of a l l t r a i n i n g cards cons i s ted of a v e r t i c a l l i n e and a l i n e t i l t e d 33 degrees from the v e r t i c a l . When p o s i t i o n and d i r e c t i o n of t i l t were counterbalanced there were four t r a i n i n g cards; t i l t i n the clockwise d i r e c t i o n on the r i g h t s ide of the c a r d ; t i l t i n counterclockwise d i r e c t i o n on the r i g h t s ide of the c a r d ; t i l t i n c l o c k -wise d i r e c t i o n on the l e f t s ide of the card; t i l t i n counterclockwise d i r e c t i o n on the l e f t s ide of the c a r d . The t e s t cards had, i n a d d i t i o n to the v e r t i c a l standard and v e r t i c a l comparison, one of ten d i f f e r e n t l i n e t i l t s : 1 ° , 2 ° , 4 ° , 6 ° , 9 ° , 1 2 ° , 1 5 ° , 2 1 ° , 2 7 ° , and 3 3 ° . P o s i t i o n and d i r e c t i o n of t i l t were counterbalanced. The cards were presented on a wooden board that was r a i s e d towards the subject at an angle of 30 degrees from the t a b l e . 3 3 Procedure A l l subjects were i n d i v i d u a l l y tested by the same experimenter ( J . A . ) . The c o n t r o l subjects were tested at the school they were a t tending; the subjects i n the a u t i s t i c group were tested at L a u r e l House. On enter ing the room, the subject was seated at a small tab le so that he was d i r e c t l y fac ing the st imulus cards wi th the standard st imulus at e y e - l e v e l . The experimenter was seated to h i s l e f t . The experimenter t o l d the subject that he was going to p lay a game, and that the subject would rece ive a marble i f he was c o r r e c t . However, the experimenter explained that because there were not enough marbles , the subject would sometimes not rece ive a marble even though he was c o r r e c t , but that he was not to worry, because the experimenter was keeping t rack of h i s responses by recording them on paper. The subject was a l so informed that a marble would be withdrawn for every i n c o r r e c t response (c f . Winer, 1962). The r e i n f o r c e r s were b r i g h t l y coloured marbles . A c l e a r p l a s t i c container was placed near the subject i n a p o s i t i o n where he could c l e a r l y see i t . At the beginning of a se s s ion , the experimenter and the subject together counted ten marbles and placed them in to the p l a s t i c conta iner . The subject was then shown a matchbox toy and t o l d that i f he earned s u f f i c i e n t number of marbles he could have the toy i n exchange for the marbles at the end of the sess ion . During the second t r a i n i n g se s s ion , the experimenter informed the subject that the number of marbles he had at the end of the sess ion would determine the type of toy he could o b t a i n . I f he obtained a great number of marbles at the end of the sess ion he was 34 e n t i t l e d to a more a t t r a c t i v e toy. A l l subjects were r e i n f o r c e d for choosing the v e r t i c a l comparison. The i n s t r u c t i o n s to the subjects were: "Touch the l i n e that i s l i k e the l i n e above.". Reinforcement was presented only when the subject had placed his whole hand on the comparison st imulus or when he had one or more of h i s f ingers touching i t . When the subject f a i l e d to touch e i ther of the l i n e s , the experimenter repeated the i n s t r u c t i o n s u n t i l he d i d . Each subject rece ived two t r a i n i n g sessions and three tes t sess ions . The sessions were conducted on d i f f e r e n t days with not more than three days in terven ing between two sess ions . T r a i n i n g s tar ted wi th a continuous reinforcement (CRF) schedule on which the subject rece ived a marble for every correc t response. The subject l o s t a marble for every i n c o r r e c t response. A f t e r 12 consecutive correc t t r i a l s , the schedule was gradua l ly s h i f t e d to f i x e d r a t i o 2 (FR2), f i x e d r a t i o 3 (FR3) and f ixed r a t i o 4 (FR4) . Each s h i f t from one schedule to another was preceded by 12 consecutive correc t t r i a l s . On the FR2 schedule, the subject was r e i n f o r c e d for every second consecutive correc t response. S i m i l a r l y , on the FR3 schedule, the subject was re in forced for every t h i r d consecutive correc t response, and on FR4, reinforcement was presented for every four th consecutive correc t response. An i n c o r r e c t response was always fol lowed by the withdrawal of a marble. On the unre inforced t r i a l s the subjec t ' s response was recorded and the next t r i a l i n i t i a t e d . Sometimes the subject questioned the experimenter as to why he had not rece ived a marble. The subject would then be reminded that even though he was c o r r e c t , he would not always rece ive a marble because there were not enough marbles , but 35 that he was not to worry, because the experimenter was keeping record of his responses. Otherwise, verbal interactions were kept to a minimum, although the experimenter would, on occasion, repeat the words "Touch the line that is like the line above", when i t seemed that the subject was not attending to the task. The duration of the i n t e r t r i a l interval was approximately 10 seconds. The training session terminated when the subject had reached a criterion of 20 to 24 consecutive correct t r i a l s on the FR4 schedule or after 40 minutes, whichever came f i r s t . After two training sessions, test sessions commenced. Prior to a l l test sessions, subjects received a brief training session to ensure that their responses would be main-tained by the FR4 schedule. The session started with a CRF schedule which was followed by FR2 and FR3 schedules. Each shift was preceded by four consecutive correct t r i a l s . After 6 consecutive t r i a l s on the FR3 schedule, the FR4 schedule was introduced and maintained un t i l the subject had achieved 12 correct t r i a l s . The test cards were then presented. Fifty-three cards were presented during test sessions. Thirteen were training cards (vertical and 33 degree line t i l t comparison stimuli), and forty were test cards which had as one comparison a line t i l t that more closely approached ver t i c a l . During testing, an attempt was made to maintain the same schedule that was used during training. The t r i a l s were presented i n blocks of four. Each block consisted of the presentation of three test cards followed by a training card. There were, altogether, twelve such blocks; the last and thirteenth block of t r i a l s consisted of the presentation of four test cards followed by a training card. The 36 l a s t card of every b lock was the c r i t i c a l card for reinforcement . I f the subject responded c o r r e c t l y on t h i s t r i a l (i. . e_., chose the v e r t i c a l comparison), he rece ived a marble. An i n c o r r e c t response to t h i s card r e s u l t e d i n the loss of a marble. The subjec t ' s responses to each tes t st imulus card were recorded. Subjects d i d not rece ive marbles for correc t responses to the tes t cards . I f a subject questioned the experimenter about not being re in forced on these t r i a l s , the experimenter would repeat that there were not enough marbles and hence the subject would not rece ive a marble for every correc t response. Incorrect responses to the tes t cards d id not r e s u l t i n the withdrawal of marbles . Except for pre -arrang ing for a t r a i n i n g card to appear at the end of every b lock , the order of tes t card presentat ion was random. Fol lowing the t h i r d tes t ses s ion , subjects were presented with a d i f f e r e n t t r a i n i n g task. The aim of the task was to determine the number of t r i a l s necessary for a subject to d i s c r i m i n a t e between a v e r t i c a l l i n e and a t i l t e d l i n e to a c r i t e r i o n of 8 consecutive correc t t r i a l s . As i n the f i r s t part of the experiment, subjects were presented with the standard st imulus ( v e r t i c a l l i n e ) , a v e r t i c a l comparison l i n e , and a comparison l i n e t i l t e d from the v e r t i c a l e i t h e r 1 2 ° , 9 ° , 6 ° , 5 ° , 4 ° , 3 ° , 2 ° , or 1 ° . P o s i t i o n and d i r e c t i o n of t i l t were counterbalanced and the four cards for each l i n e t i l t made up a set . Th i s task i s d i f f e r e n t from the previous task i n that a p a r t i c u l a r l i n e t i l t was presented repeatedly to the subject u n t i l a c r i t e r i o n of 8 consecutive correc t t r i a l s was reached or a f t e r 28 presentat ions of that l i n e t i l t had been made. The f i r s t set of cards presented was the one wi th the v e r t i c a l 3 7 a n d 1 2 " c o m p a r i s o n l i n e . T h e s u b j e c t w a s r e i n f o r c e d f o r c h o o s i n g t h e v e r t i c a l c o m p a r i s o n . F o r e v e r y c o r r e c t r e s p o n s e , t h e s u b j e c t r e c e i v e d a m a r b l e . E v e r y i n c o r r e c t r e s p o n s e w a s f o l l o w e d b y t h e w i t h d r a w a l o f a m a r b l e . W h e n t h e s u b j e c t h a d r e a c h e d t h e c r i t e r i o n o f 8 c o n s e c u t i v e c o r r e c t t r i a l s , t h e e x p e r i m e n t e r p r o c e e d e d t o p r e s e n t t h e n e x t s e t o f c a r d s , t h a t i s , t h o s e w i t h t h e v e r t i c a l a n d t h e 9 ° c o m p a r i s o n . T h e p r o c e d u r e w a s t h e n r e p e a t e d . T h e p r o c e d u r e w a s a l s o r e p e a t e d f o r t h e 6 ° , 5 ° , 4 ° , 3 ° , 2 ° a n d 1 ° c o m p a r i s o n l i n e t i l t s i n t h a t o r d e r . I f t h e s u b j e c t f a i l e d t o r e a c h * . . c r i t e r i o n a f t e r 2 8 p r e s e n t a t i o n s o f a p a r t i c u l a r l i n e t i l t , t h e e x p e r i m e n t e r p r o c e e d e d t o p r e s e n t t h e n e x t s e t o f c a r d s . R e s u l t s T a b l e I s h o w s t h e n u m b e r o f t r i a l s t a k e n b y s u b j e c t s t o r e a c h c r i t e r i o n o f 2 4 c o n s e c u t i v e c o r r e c t t r i a l s o n t h e F R 4 s c h e d u l e d u r i n g t r a i n i n g i n t h e f i r s t p a r t o f E x p e r i m e n t I . A s c a n b e s e e n i n T a b l e I , t h e a u t i s t i c s u b j e c t s t o o k a g r e a t e r n u m b e r o f t r i a l s t o r e a c h t h e c r i t e r i o n o f 2 4 c o n s e c u t i v e c o r r e c t r e s p o n s e s o n t h e F R 4 s c h e d u l e d u r i n g t r a i n i n g , t h a n d i d t h e c o n t r o l s u b j e c t s . T h e l e a s t n u m b e r o f t r i a l s n e e d e d t o c o m p l e t e a t r a i n i n g s e s s i o n w a s 6 0 t r i a l s . E a c h s h i f t f r o m s c h e d u l e s C R F t o F R 2 a n d F R 3 h a d t o b e p r o c e e d e d b y 1 2 c o n s e c u t i v e c o r r e c t t r i a l s , a n d t h e c r i t e r i o n f o r t h e F R 4 s c h e d u l e w a s 2 4 c o n s e c u t i v e c o r r e c t t r i a l s . S u b j e c t s S A 1 , S A 2 a n d S A 3 i n t h e a u t i s t i c g r o u p t o o k 8 2 , 7 8 a n d 6 7 t r i a l s r e s p e c t i v e l y . T h e a v e r a g e n u m b e r o f t r i a l s f o r t h e g r o u p w a s 7 5 . 6 7 t r i a l s . A l l o f t h e c o n t r o l s u b j e c t s w i t h t h e e x c e p t i o n o f S C 1 , t o o k o n l y 6 0 38 Table I Number of t r i a l s taken by subjects to reach c r i t e r i o n of twenty four consecutive correc t t r a i l s on the FR4 schedule during t r a i n i n g i n the f i r s t part of Experiment I . The minimum number of t r i a l s needed to complete a t r a i n i n g sess ion was 60. Group Number of t r i a l s to c r i t e r i o n A u t i s t i c Group SA 1 82 SA 2 78 SA 3 67 Contro l Group SC 1 62 SC 2 60 SC 3 60 SC 4 60 39 t r i a l s to reach c r i t e r i o n during t r a i n i n g . SC 1 made two e r r o r s at the beginning of the t r a i n i n g s e s s i o n and acquired a f t e r 62 t r i a l s . The average number of t r i a l s taken by the c o n t r o l s u b j e c t s to acquire c r i -t e r i o n was 60.5. In the t e s t f o r the degree of c o n t r o l by the l i n e t i l t , l i t t l e d i f f e r e n c e was found between a u t i s t i c and c o n t r o l s u b j e c t s . The tendency to choose the t i l t e d l i n e r a t h e r than the v e r t i c a l l i n e on the t e s t cards, was greater f o r the c o n t r o l s u b j e c t s than the a u t i s t i c s u b j e c t s (see F i g . 1 ) . Fi g u r e 1 shows the number of responses made by a u t i s t i c and c o n t r o l s u b j e c t s to the v a r i o u s l i n e t i l t s d uring t e s t f o r stimulus con-t r o l i n Experiment I . The. averagel.numbef of times that the n o n - v e r t i c a l l i n e t i l t was chosen during the p r e s e n t a t i o n of t e s t cards was 11 f o r the c o n t r o l group and 9.33 f o r the a u t i s t i c group (see F i g . 2). This was c a l c u l a t e d from F i g u r e 2 which shows the t o t a l number of responses to the n o n - v e r t i c a l comparison l i n e t i l t s made by a u t i s t i c and c o n t r o l s u b j e c t s . None of the a u t i s t i c s chose l i n e t i l t s greater than 4°. However, SC 3 of the c o n t r o l group chose the t i l t e d l i n e when presented w i t h a v e r t i c a l and 9° l i n e t i l t . I n the second p a r t of Experiment I , sub j e c t s were r e q u i r e d to d i s -c r i m i n a t e between a v e r t i c a l and t i l t e d l i n e to a c r i t e r i o n of 8 consecutive c o r r e c t t r i a l s . Again, there was l i t t l e d i f f e r e n c e between the a u t i s t i c and c o n t r o l subjects (see Table I I ) . Table I I shows the number of t r i a l s taken by su b j e c t s to reach c r i t e r i o n i n Experiment I par t two. As can be seen i n Table I I , two- of the a u t i s t i c s and three of the c o n t r o l s f a i l e d to reach c r i t e r i o n of 8 consecutive t r i a l s when presented w i t h a v e r t i c a l V) 1 0 -UJ to 9 -ON 8 -CL 7 -U) 111 6 -cc LL 5 -o 4 -ER 3 -CO 2 -1 -0 -z SA-I I I I I I I l I I \"~\ 1 2 4 6 9 12 3 3 D E G R E E S F R O M V E R T I C A L 1 0 - | 9 - S A 2 1 0 -9 - SAg 1 0 -9 -8 - 8 - 8 -7 - 7 - 7 -6 - 6 - \ 6 -5 - 5 - \ 5 -4 - 4 - 4 -3 - \ 3 - 3 -2 - V 2 - \ 2 -1 - \ 1 - 1 -o- \ . » • / h* 0 - o-I I I I I I I TTT\ I' h h i i II i i 11 i i 1 2 4 6 9 12 3 3 1 2 4 6 9 12 3 3 A U T I S T I C — C O N T R O L o I I I I I I II I M I'*1 1 2 4 6 9 1 2 3 3 1: Number of responses made by autistic and control subjects to the various line tilts during test for stimulus control in Experiment I. The top right-hand panel gives the average number of responses to the line t i l t made by each group. 41 SA 1 SA 2 SA 3 A u t i s t i c Group SC 1 SC 2 SC 3 C o n t r o l Group SC 4 F igure 2: T o t a l number of responses to n o n - v e r t i c a l comparison l i n e t i l t s made by a u t i s t i c and c o n t r o l subjects i n Experiment I , part 1. 42 Table II Number of t r i a l s taken by subjects to reach c r i t e r i o n of e ight consecutive correc t t r i a l s i n Experiment I part two. The symbol * i n d i c a t e s that subject d i d not reach c r i t e r i o n . Group L i n e T i l t (degrees from v e r t i c a l ) 12 9 6 5 4 3 2 1 A u t i s t i c Group SA 1 8 8 8 8 8 16 13 * SA 2 8 8 8 8 8 8 16 26 SA 3 8 8 8 8 8 8 16 * ; r o l Group SC 1 8 8 8 14 9 12 24 * SC 2 8 8 8 8 8 28 * 14 SC 3 8 8 8 8 8 8 8 * SC 4 8 8 8 8 8 8 17 * 43 and 1 ° l i n e t i l t . Only SC 2 of the c o n t r o l group f a i l e d to reach c r i t e r i o n when presented wi th a v e r t i c a l l i n e and a 2 ° l i n e t i l t . i A l l other subjects reached c r i t e r i o n on the 2 ° l i n e t i l t , a lthough the number of t r i a l s needed to reach c r i t e r i o n v a r i e d cons iderably between subjec t s . Th i s was e s p e c i a l l y so f o r the c o n t r o l group. For example, SC 3 took only 8 t r i a l s to reach c r i t e r i o n whi le SC 1 took 28 t r i a l s to reach c r i t e r i o n . For l i n e t i l t s greater than 3 ° , none of the a u t i s t i c subjects took more than the minimum number of t r i a l s to reach c r i t e r i o n , _i._e. , 8 t r i a l s . However, i n the case of the c o n t r o l group, SC 1 took 9 t r i a l s to reach c r i t e r i o n on the 4 ° l i n e t i l t , and 14 t r i a l s on the 5 ° l i n e t i l t . D i scuss ion The only apparent d i f f erence between the a u t i s t i c and c o n t r o l subjects found i n Experiment I was the number of t r i a l s taken to reach c r i t e r i o n of 24 consecutive correc t t r i a l s on the FR 4 schedule during t r a i n i n g . Although the a u t i s t i c subjects needed more t r i a l s than the contro l s to reach c r i t e r i o n , t h i s d i f f erence was not extremely l a r g e . A l s o , t h i s d i f f e r e n c e was not r e p l i c a t e d the second part of Experiment I , i n which subjects were required to d i s c r i m i n a t e between a v e r t i c a l and a t i l t e d l i n e to a c r i t e r i o n of 8 consecutive correc t t r i a l s . In the subsequent tes t for the degree of c o n t r o l by the l i n e t i l t , there was no apparent d i f f e r e n c e between the two groups. I t i s p o s s i b l e that the task i n Experiment I was too simple to detect any d i f f erences i n dimensional st imulus c o n t r o l between the groups. Given the length 44 of the lines in Experiment I, even a 2 U line t i l t showed a noticeable displacement from the ver t i c a l . However, a shorter line that is t i l t e d at the same angle from the vertical would show less spatial displacement from the top of the ver t i c a l , thus making i t more d i f f i c u l t to detect differences between comparison stimuli. Differences between the autistic and control subjects in dimensional control by line t i l t might show up more clearly i f differences between the vertical lines and the t i l t e d lines were made smaller. Thus, in Experiment II, the lines were shortened. In addition, the angle of the line t i l t s was varied at smaller intervals. For the line t i l t s less than 4°, the angle of the t i l t s was varied at 1/2° intervals. Experiment II The general procedure was the same as that in Experiment I, part one, with the exception that the standard and comparison stimuli consisted of shorter lines and the angle of the t i l t e d comparison was varied at smaller intervals during the dimensional control test. Method Stimuli The stimuli were basically the same as those in Experiment I. They consisted of lines of different orientations drawn with a black f e l t pen on 22.5 cm by 30.3 cm white cards. The lines were 19 mm long by .5 mm 45 wide. The standard stimulus ( v e r t i c a l l i n e ) was drawn on the upper h a l f of a l l cards . The comparison s t i m u l i were drawn on the lower h a l f of the cards . The comparison s t i m u l i of a l l t r a i n i n g cards cons i s ted of a v e r t i c a l l i n e and a l i n e t i l t e d at 3 3 ° from the v e r t i c a l . P o s i t i o n and d i r e c t i o n of t i l t were counterbalanced. The tes t cards , had, i n a d d i t i o n to the v e r t i c a l standard and v e r t i c a l comparison, one of 11 d i f f e r e n t l i n e t i l t s : 0 . 5 ° , 1 . 0 ° , 1 . 5 ° , 2 . 0 ° , 2 . 5 ° , 3 . 0 ° , 3 . 5 ° , 4 . 0 ° , 5 . 0 ° , 6 . 0 ° and 1 5 ° . P o s i t i o n and d i r e c t i o n of t i l t were counterbalanced on d i f f e r e n t cards . Procedure The general procedure was the same as that i n Experiment I , part one. P r i o r to each tes t s e s s ion , subjects rece ived a b r i e f t r a i n i n g sess ion (refer to Experiment I) which terminated when the subjects had achieved 12 consecutive correc t t r i a l s ( t r i a l s on which the v e r t i c a l comparison was se lected) on the FR4 schedule. The same i n s t r u c t i o n s used i n Experiment I , were given to the subjec t s . A l l subjects were r e i n f o r c e d for choosing the v e r t i c a l l i n e . Reinforcement was only presented when the subject had placed h i s whole hand on, or when he had.one or more of h i s f ingers touching the correc t s t imulus . Each subject rece ived three tes t sess ions . The f i r s t tes t sess ion was conducted not more than three days a f t e r the l a s t sess ion i n Experiment I . The sess ions were conducted at i n t e r v a l s of three days or l e s s . 46 F i f t y - n i n e cards were presented dur ing the tes t sess ions . F i f t e e n were t r a i n i n g cards ( v e r t i c a l and 3 3 ° l i n e t i l t comparisons) and 44 were t e s t cards . The cards were presented i n 14 blocks of four cards each. Each b lock cons is ted of three tes t cards and a t r a i n i n g c a r d . The l a s t and f i f t e e n t h b lock cons i s ted of only 3 cards; the f i r s t two were tes t cards and the l a s t card was a t r a i n i n g c a r d . The order of t es t card presentat ions was randomly arranged with the exception that a t r a i n i n g card appeared at the end of every b lock . I f the subject responded c o r r e c t l y to the l a s t card of a b l o c k , he rece ived a marble. An i n c o r r e c t response to a t r a i n i n g card l ed to withdrawal of a marble. The subject was not r e i n f o r c e d for correc t responses to the tes t cards , ne i ther d i d he lose a marble for responding i n c o r r e c t l y . Results There was again l i t t l e d i f f erence between the a u t i s t i c group and the c o n t r o l group, as can be seen i n F igure 3 which shows the number of responses made by a u t i s t i c and c o n t r o l subjects to the var ious l i n e t i l t s during tes t for st imulus c o n t r o l i n Experiment I I . However, the tendency to choose the n o n - v e r t i c a l l i n e t i l t ra ther than the v e r t i c a l l i n e was s l i g h t l y greater for the a u t i s t i c group than the c o n t r o l group. The average number of times that the n o n - v e r t i c a l l i n e t i l t was chosen during the presentat ion of the tes t cards was 21 for the contro l s and 23 for the a u t i s t i c s . There was more v a r i a b i l i t y among the c o n t r o l subjects (range: c o n t r o l 14-31; a u t i s t i c s 20-27; see F igure 4) . The t o t a l number of responses to n o n - v e r t i c a l l i n e t i l t s made by a u t i s t i c and c o n t r o l subjects i n Experiment I I , i s shown i n F igure 4. None of the a u t i s t i c subjects responded 1 0 -UJ 9 -V) Z 8 -O a. 7 " V) UJ 6-CC LL 5-O 4 -ER 3-MB 2 -1 -o-Z SAi i • i • \ * i 1 i 1 i > 1 1 2 3 4 6 3 3 D E G R E E S F R O M V E R T I C A L 1 0 - i 9 -8 -7 -6 5 H 4 3 -2 -1 -0 -S A 2 i • i 1 2 T " 3 4 6 3 3 1 0 -9 -8 -7 -6 -5-4 -3 -2 -1 -0 -SA< I i I 1 I i I ' I 1 l / H 1 2 3 4 6 3 3 10 9 8 a 5 4 3 2 1 0 A U T I S T I C • -C O N T R O L »-"b-o. 1 I 1 I 1 I ' I ' I 1 1 ^ 1 2 3 4 6 3 3 1 0 -9 -8 -7 -6-5-4 -3 -2 -1 -0 -SCi I 1 I 1 I 1 I 1 I 1 1 2 3 4 6 3 3 1 0 -9 -8 -7 -6 -5-4 -3 -2 -1 -0 -T S C 3 3 4 6 3 3 1 0 -9 -8 -7 -6 -5" 4 -3 -2 -1-0 -s c 4 i 1 i ' i ' i ' i 1 1 2 3 4 6 3 3 Figure 3: Number of responses made by a u t i s t i c and c o n t r o l s ubjects to the v a r i o u s l i n e t i l t s d u r i n g t e s t f o r stimulus c o n t r o l i n Experiment I I . The t o p - r i g h t hand panel gives the average number of responses to the l i n e t i l t made by each group. SA 1 SA 2 SA 3 SC 1 SC 2 SC 3 SC 4 A u t i s t i c Group Contro l Group F igure 4: T o t a l number of responses to n o n - v e r t i c a l comparison l i n e t i l t s made by a u t i s t i c and c o n t r o l subjects i n Experiment I I . 49 to the t i l t e d l i n e when the angle of the t i l t was greater than 2.5° from the v e r t i c a l . I n the case of the c o n t r o l group, SC 1 responded to the 4° l i n e t i l t , and SC 2 responded to the 3° l i n e t i l t (see Fi g u r e 3 ). None of the c o n t r o l subjects responded to the t i l t e d l i n e when the angle of the t i l t was greater than 4°. I t i s noteworthy that subjects i n both groups made a greater number of responses to the t i l t e d l i n e during g e n e r a l i z a t i o n t e s t s of Experiment I I , than during the g e n e r a l i z a t i o n t e s t s of Experiment I . This r e s u l t suggests that the d i f f e r e n c e s i n l i n e o r i e n t a t i o n s i n Experiment I I were i n f a c t more d i f f i c u l t to detect than the d i f f e r e n c e s i n l i n e o r i e n t a t i o n s i n Experiment I . D i s c u s s i o n The r e s u l t s of Experiment I I a l s o f a i l e d to demonstrate greater stimulus c o n t r o l i n a u t i s t i c s u b j e c t s than i n c o n t r o l s u b j e c t s . The r e -s u l t s of Experiments I and I I which show that a u t i s t i c c h i l d r e n are con-t r o l l e d by l i n e o r i e n t a t i o n s to the same extent as normal c h i l d r e n , i s i n c o n s i s t e n t w i t h Hermelin and O'Connor's n o t i o n that a u t i s t i c c h i l d r e n are p a r t i c u l a r l y unresponsive to v i s u a l s t i m u l i . 5he question may be r a i s e d as to whether a u t i s t i c c h i l d r e n would do as w e l l as c o n t r o l c h i l d r e n when the task i n v o l v e s d i s c r i m i n a t i n g d i f f e r e n c e s between s t i m u l i that are v a r i e d along two dimensions i n s t e a d of j u s t one. I f a u t i s t i c c h i l d r e n tend to be c o n t r o l l e d by only one aspect of a s t i m u l u s , then they would have great d i f f i c u l t y i n l e a r n i n g a mul t i d i m e n s i o n a l d i s c r i m i n a t i o n task. 50 In the t h i r d experiment, subjects were presented wi th a task i n which they had to match the standard stimulus wi th one of four s t i m u l i that v a r i e d i n shape as w e l l as i n the presence or absence of a s tar w i t h i n the shape. It should be pointed out that the s t i m u l i i n Experiment I I I d i d not c o n s t i t u t e a dimension l i k e the l i n e o r i e n t a t i o n s of Experiments I and I I . As such, Experiment I I I cannot be considered a tes t of dimensional st imulus c o n t r o l . Rather, i t was a tes t of the subjec t ' s a b i l i t y to d i s c r i m i n a t e between four s t i m u l i that v a r i e d along two dimensions. Experiment I I I Subjects were t ra ined to match a standard st imulus wi th one of four comparison s t i m u l i that v a r i e d i n shape and i n the presence or absence of a s tar w i t h i n the shape. The number of t r i a l s needed to reach c r i t e r i o n of 8 consecutive correc t responses was recorded. Method S t i m u l i The s t i m u l i cons is ted of two d i f f e r e n t shapes, an e l i p s e and an oblong sphero id , which i s a c i r c l e that has been f la t t ened at the po le s . As w e l l , the s t i m u l i were d i f f e r e n t i a t e d by the presence or absence of a b lack s t a r . Thus, there were four s t i m u l i : Two e l i p s e s , one wi th a s t a r and one without; and two oblong spheroids , one wi th a s tar and one without a s t a r . With the a i d of p l a s t i c templates, the shapes were drawn with a b lack f e l t pen on 22. 5 cm by 30.3 cm white cards . Both 51 the e l i p s e s and the oblong spheroids were approximately 29 mm long . The heights of the e l i p s e and the oblong spheroid were 17 mm and 12 mm r e s -p e c t i v e l y . Using a r o l l of deca-dry symbols, a s t a r was t rans ferred to the centre of the appropriate shapes. Unl ike i n Experiments I and I I , one p a r t i c u l a r st imulus was not always the standard s t imulus . The four s t i m u l i were rotated so that each st imulus became the standard st imulus twice. The standard st imulus was drawn on the top h a l f of the cards . The four comparison s t i m u l i were drawn on the lower h a l f of the cards , at equa l ly spaced i n t e r v a l s of 1.5 cm l eav ing a margin of 3 cm on e i t h e r s ide of the c a r d . The sequent ia l arrangement of the four comparison s t i m u l i was randomized wi th the exception that the comparison st imulus that matched the standard st imulus never appeared i n the same p o s i t i o n more than twice . The order of the presentat ion of the e ight cards was randomized. Procedure As t h i s experiment was conducted 10 days a f t e r the l a s t sess ion of Experiment I I , a l l subjects were given a b r i e f t r a i n i n g sess ion (see Experiment I ) , to r e f a m i l i a r i z e them with the matching-to-sample procedure The t r a i n i n g cards of Experiment I were used. Subjects were t r a i n e d to d i s c r i m i n a t e between a v e r t i c a l l i n e and a l i n e t i l t e d at 3 3 ° from the v e r t i c a l , to a c r i t e r i o n of 12 consecutive correc t t r i a l s on the FR4 schedule. The experimenter then informed the subjects that they were going to p lay a game that was s i m i l a r to that which they had played p r e v i o u s l y . The 52 experimenter explained that the subjects would rece ive a marble every-time they responded c o r r e c t l y , and that each time they responded i n -c o r r e c t l y , they would lose a marble. At the end of the experiment, they could exchange the marbles for matchbox toyes . A l l subjects were r e i n f o r c e d for choosing the st imulus that matched the standard s t imulus . The i n s t r u c t i o n s to the subjects were: "Touch the object that i s l i k e the one above.". When the subject had one or more of t h e i r f ingers touching the correc t comparison s t i m u l i , they were given a marble. I f a wrong comparison st imulus was chosen, the experimenter withdrew a marble from the p l a s t i c container that had been placed on the tab le near the subject . The sess ion was terminated when the subject had made 8 consecutive correc t responses. Results The a u t i s t i c subjects i n general took a greater number of t r i a l s to reach c r i t e r i o n of 8 consecutive correc t responses than the normal subjec t s . The number of t r i a l s taken by subjects to reach c r i t e r i o n of 8 consecutive c o r r e c t t r i a l s i n Experiment I I I i s shown i n Table I I I . Three of the c o n t r o l subjects reached c r i t e r i o n i n 8 t r i a l s , which was the minimum number of t r i a l s needed. SC 1 took 9 t r i a l s to reach c r i t e r i o n . Of the a u t i s t i c subjec t s , only SA 2 reached c r i t e r i o n i n 8 t r i a l s . SA 1 took 20 t r i a l s , and SA 3, 13 t r i a l s to reach c r i t e r i o n . 53 Table I I I Number of t r i a l s taken by subjects to reach c r i t e r i o n of e ight consecutive correc t t r i a l s i n Experiment I I I . Group Number of t r i a l s to c r i t e r i o n A u t i s t i c Group SA 1 20 SA 2 8 SA 3 13 Contro l Group SC 1 9 SC 2 8 SC 3 8 SC 4 8 54 D i s c u s s i o n The r e s u l t s of Experiment I I I suggest that a u t i s t i c c h i l d r e n have d i f f i c u l t y i n d i s c r i m i n a t i n g between m u l t i d i m e n s i o n a l s t i m u l i . However, the d i f f e r e n c e between the a u t i s t i c s ubjects and the c o n t r o l subjects i n the number of t r i a l s taken to reach the c r i t e r i o n of 8 consecutive c o r r e c t t r i a l s , was not l a r g e . I t could be argued that t h i s i s evidence that the responses of a u t i s t i c c h i l d r e n tend to be brought under the c o n t r o l of only one aspect of the s t i m u l i . However, i f the responses of the a u t i s t i c c h i l d r e n were under the c o n t r o l of only one aspect of the s t i m u l i , none of the a u t i s t i c s u b j e c t s would have reached c r i t e r i o n , s i n c e i t was necessary to attend to both the shape of the s t i m u l i and the presence or absence of the s t a r w i t h i n i t , i n order to respond c o r r e c t l y to a l l e i g h t cards. A l t e r n a t i v e l y , the greater number of e r r o r s made by the a u t i s t i c c h i l d r e n compared to the normal c h i l d r e n , could be a t t r i b u t e d to the greater number of comparison s t i m u l i made a v a i l a b l e to the su b j e c t s . The f i n d i n g s of a study by Hermelin and O'Connor (1967) suggest that a u t i s t i c c h i l d r e n attend to a stimulus d i s p l a y f o r s h o r t e r times than normal c h i l d r e n . I t i s p o s s i b l e that when a l a r g e amount of s t i m u l i are presented, a u t i s t i c c h i l d r e n take a longer time than normal c h i l d r e n to gain the same amount of i n f o r m a t i o n from the stimulus d i s p l a y . 55 C h a p t e r I I I : D I S C U S S I O N The r e s u l t s of Experiment I and II f a i l e d to show any great d i f f erences between the a u t i s t i c and the c o n t r o l subjec t s . In the tes t for the degree of c o n t r o l by the l i n e t i l t the d i f f e r e n c e between the a u t i s t i c s and the contro l s were very s l i g h t . The only apparent d i f f erence between the two groups of subjects was i n the number of t r i a l s taken to reach c r i t e r i o n of 24 correc t t r i a l s on the FR4 schedule during t r a i n i n g i n Experiment I . The a u t i s t i c subjects took a greater number of t r i a l s than the con-t r o l s to reach c r i t e r i o n during t r a i n i n g , although the d i f f e r e n c e was not extremely l a r g e . A l s o , t h i s d i f f erence was not r e p l i c a t e d i n the second part of Experiment I i n which subjects were t ra ined to d i s c r i m i n a t e be-tween a v e r t i c a l l i n e and l i n e s t i l t e d progres s ive ly c l o s e r to the v e r t i c a l . In Experiment I I I the a u t i s t i c subjects took a greater number of t r i a l s to reach the c r i t e r i o n of 8 consecutive correc t t r i a l s on a mult id imensional d i s c r i m i n a t i o n task. Again the d i f f e r e n c e was not that c l e a r . I t i s i n t e r e s t i n g to note that the a u t i s t i c subjects i n the present study d i s cr iminated very small d i f f erences i n l i n e o r i e n t a t i o n s , and that they d id not d i f f e r very s i g n i f i c a n t l y from the c o n t r o l subjects i n terms of d i s c r i m i n a t i n g d i f f erences i n l i n e o r i e n t a t i o n s . A l l the a u t i s t i c subjects d i scr iminated between a v e r t i c a l and a 2 ° l i n e t i l t to a c r i t e r i o n of 8 consecutive correc t t r i a l s (see Experiment I , part two). The degree to which a u t i s t i c subjects d i scr iminated l i n e o r i e n t a t i o n s argues against Hermelin and O'Connor's p r o p o s i t i o n that there i s impaired v i s u a l d i s c r i m i n a t i o n i n a u t i s t i c c h i l d r e n . The subjects i n Hermelin and O'Connor's ( 1 9 6 5 ) s t u d y 56 were unable to d i s c r i m i n a t e between a h o r i z o n t a l and a v e r t i c a l l i n e . The d i s p a r i t y between the f ind ings of the present study and that of Hermelin and O'Connor's could be a func t ion of the procedure employed. H e r e l i n and O'Connor d i d not employ a matching-to-sample procedure. In order to do w e l l i n a task i n which the standard st imulus i s not provided the c h i l d not only has to be able to d i s c r i m i n a t e between s t i m u l i , but he a l so has to r e c a l l the consequences of h i s previous response. Over and Over (1967) have demonstrated the importance of d i s t i n g u i s h i n g between the two processes . The experimental r e s u l t s obtained by Hermelin and O'Connor (1965) and the f ind ings of the present study suggest that the problems wi th a u t i s t i c c h i l d r e n i s r e l a t e d to memory f a c t o r s . When a u t i s t i c c h i l d r e n were presented with a standard st imulus wi th which to compare the choice s t i m u l i , as was done i n the present study, t h e i r performance d i d not d i f f e r from normal c h i l d r e n . An i n t e r e s t i n g fo l low-up study would be to conduct a study i n which the standard st imulus was gradua l ly faded out once response had reached the des ired c r i t e r i o n . I f response s trength showed a marked dec l ine when the standard st imulus was removed, then one could conclude that the unrespons iv i ty i n a u t i s t i c c h i l d r e n i s d i r e c t l y r e l a t e d to t h e i r f a i l u r e to r e c a l l previous experiences . For the purpose of the present s tudy, the d e f i n i t i o n of st imulus s e l e c t i v i t y was extended to inc lude steep dimensional c o n t r o l gradients and the a b i l i t y to d i s c r i m i n a t e small d i f f erences between s t i m u l i that l i e along a s p e c i f i c dimension. The f a i l u r e to obta in steeper l i n e t i l t gradient and any marked d i f ferences i n d i s c r i m i n a t i o n a c q u i s i t i o n i n the present study suggests that at l e a s t wi th unidimensional s t i m u l i , s t imulus 57 s e l e c t i v i t y i s not greater i n a u t i s t i c than i n normal c h i l d r e n . In l i s t i n g the obvious q u a l i f i c a t i o n s that had to be imposed on the data he obtained, Lovaas et a l (1971) pointed out that the s t i m u l i elements i n h i s study were d i s t r i b u t e d across m o d a l i t i e s . He surmised that i f a l l the stimulus elements had f a l l e n w i t h i n one modality, the r e s u l t s obtained may have been d i f f e r e n t . In the present study the s t i m u l i were of the v i s u a l modality only. In Experiment I I I , the a u t i s t i c s u b j e c t s took a greater number of t r i a l s to reach the c r i t e r i o n of 8 consecutive c o r r e c t t r i a l s than d i d the c o n t r o l s . This r e s u l t may seem to suggest that the responses of a u t i s t i c c h i l d r e n tend to be brought under the c o n t r o l of only one aspect of the sti m u l u s . However, i f t h i s was the case, none of the a u t i s t i c s u b j e c t s would have reached c r i t e r i o n as i t was necessary to attend to both the shape of the s t i m u l i and the presence or absence of the s t a r w i t h i n i t , i n order to respond c o r r e c t l y to a l l 8 cards. A l t e r n a t i v e l y , the greater number of e r r o r s made by the a u t i s t i c s u b j e c t s compared to the c o n t r o l s u b j e c t s could be a t t r i b u t e d to the greater number of comparisons made a v a i l a b l e to the s u b j e c t s . Subjects had to choose from four comparison s t i m u l i i n s t e a d of from two, as i n Experiments I and I I . There i s some evidence which suggests that the a u t i s t i c c h i l d i s unable to attend to s t i m u l i f o r an extended p e r i o d of time. Hermelin and O'Connor (1967) found that a u t i s t i c c h i l d r e n spend more time i n non-directed gazing and l e s s time i n s p e c t i n g the v i s u a l d i s p l a y , than e i t h e r normal and subnormal c h i l d r e n . Perhaps given the nature of the v i s u a l i n s p e c t i n g behavior of the a u t i s t i c c h i l d r e n , i n c r e a s i n g the amount of s t i m u l i presented would 1 58 mean that a u t i s t i c c h i l d r e n would r e q u i r e a longer time to gain equal amount of informat ion from the same st imulus d i s p l a y than would normal c h i l d r e n . Un l ike the subjects i n the present study, the subjects i n Lovaas et a l ' s study d i d not have to d i s c r i m i n a t e between severa l mult id imens ional s t i m u l i . They were t r a i n e d only to press the bar i n the presence of the complex s t imulus , and not to press the bar during the i n t e r v a l s between st imulus complex presenta t ions . The r e s u l t s showed that a u t i s t i c subjects needed a f a r greater number of t r a i n i n g sess ions than the normals and the re tardates to l e a r n t h i s d i s c r i m i n a t i o n . In both Lovaas et a l ' s study and the present study, the s t i m u l i were mul t id imens iona l . T h i s suggests that a u t i s t i c c h i l d r e n may have d i f f i c u l t y i n dea l ing with m u l t i -dimensional d i s c r i m i n a t i o n tasks i n which they would be required to match the standard st imulus with one of s evera l comparison s t i m u l i . For example, Experiments I and II may be r e p l i c a t e d wi th the exception that the com-par i son s t i m u l i would cons i s t of s i x or more l i n e s of d i f f e r e n t o r i e n -t a t i o n s , ins tead of j u s t two. I f the problem with a u t i s t i c c h i l d r e n i s a f a i l u r e to l e a r n mult id imensional d i s c r i m i n a t i o n there should be no d i f f e r e n c e between a u t i s t i c and c o n t r o l subjects i n dimensional c o n t r o l . On the other hand, i f t h e i r problem i s r e l a t e d to f a i l u r e to attend ;,to i n c r e a s i n g numbers of s t i m u l i , then the a u t i s t i c subjects should take a greater number of t r i a l s to acquire the d i s c r i m i n a t i o n , and p o s s i b l y though not n e c e s s a r i l y , dimensional c o n t r o l should be greater i n the c o n t r o l than i n the a u t i s t i c subjec ts . I t should be noted that the a u t i s t i c subjects i n the present study 59 d i d not possess extremely severe behavior d i sorders as compared, for example, wi th the a u t i s t i c subjects i n Lovaas et a l ' s s tud ie s . Note a l so that the subjects i n the Hermelin and O'Connor s tudies (1965, 1967) were res idents of mental i n s t i t u t i o n s . They were of ten from d i f f e r e n t h o s p i t a l s and i n many cases speech development was absent. At t h i s j u n c t u r e , i t might be appropriate to c a l l a t t e n t i o n to the d i f f erences between speaking and nonspeaking a u t i s t i c c h i l d r e n . While i t may be argued that language d i sorder does not l i e at the root of the problem i n a u t i s t i c c h i l d r e n , i t i s c l e a r that d i f f erences ex i s t between speaking and nonspeaking a u t i s t i c c h i l d r e n (Hermelin and 0'Conner, 1965). I t i s p l a u s i b l e that the absence of speech development could have l ed to other complicat ions not d i r e c t l y r e l a t e d to the bas i c d i s o r d e r . The r e s u l t s of a v i s u a l d i s c r i m i n a t i o n study by Hermelin and O'Connor (1965), i n which subjects were tested on four dimensions, i n d i c a t e d that speaking a u t i s t i c c h i l d r e n d id be t t er than nonspeaking a u t i s t i c c h i l d r e n . S i m i l a r l y , F r i t h and Hermelin (1969) found that speaking and nonspeaking a u t i s t i c s d i f f e r e d i n the type of s trategy they adopted on s o l v i n g three tasks . In any case, both of the above c i t e d s tudies f a i l e d to f i n d any s i g n i f i c a n t d i f f e r e n c e between speaking a u t i s t i c c h i l d r e n and the c o n t r o l s , but there were marked and s i g n i f i c a n t d i f f erences between the nonspeaking a u t i s t i c s and the c o n t r o l s . The t h e o r e t i c a l i m p l i c a t i o n s of t h i s data i s u n c l e a r , although i n p r a c t i c e i t i s recommended that the two groups be treated d i f f e r e n t l y both i n e m p i r i c a l work and i n therapy. A l l the a u t i s t i c subjects i n the present study could speak i n t e l l i g i b l y and could fo l low simple i n s t r u c t i o n s . I t would be i n t e r e s t i n g to see what the r e s u l t s would 60 be when nonspeaking children are used as subjects. It i s often the case that the ages of the autistic children used as subjects vary considerably, especially in comparison with the age ranges of control groups. For example, in the study by Frith and Hermelin (1969), the ages of the subjects ranged from 6 to 15 years for the autistic group, 14 years to 17 years 7 months for the subnormal group and 3 years 9 months to 6 years 6 months for the normal group. In another study (Hermelin and O'Connor, 1967) the autistics ranged from 7 years to 18 years 11 months, the subnormals from 10 years to 17 years and the normals from 4 years 3 months to 6 years 1 month. Although in these cases the controls are found to perform better than the autistic subjects i t i s d i f f i c u l t to give, an unequivocal interpretation of the data. The matching of subjects on the basis of scores obtained on a pre-test, does not alter the fact that autistic children have had 10 more years of l i f e , a l l of which were possibly spent i n an institution. In the present study an attempt was made to narrow the age range as much as possible; a l l of the subjects were between the ages of 5 years 11 months and 9 years. With the age range of the subjects narrowed, there was l i t t l e difference obtained between the autistic and control subjects i n the number of t r i a l s taken to reach criterion during training. Although the autistic subjects took more t r i a l s to reach criterion during training, the criterion was reached i n the f i r s t training session and maintained at the 100 per cent level during subsequent training sessions. 61 References Ayllon, T. & Azrin, N. The token economy. New York, Appleton-rCentury-Crofts,1968. Birch, H. G. Dyslexia and the maturation of visual function. 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British Journal of Psychiatry, 1967 a, 113, 1169-1182. \ 6 4 R u t t e r , M . , G r e e n f e l d , D . a n d L o c k y e r , L . A f i v e t o f i f t e e n - y e a r f o l l o w - u p s t u d y o f i n f a n t i l e p s y c h o s i s . I I : S o c i a l a n d b e h a v i o r a l o u t c o m e . B r i t i s h J o u r n a l o f P s y c h i a t r y , 1 9 6 7 b , 1 1 3 , 1 1 8 3 - 1 1 9 9 . R u t t e r , M . C o n c e p t s o f A u t i s m : A r e v i e w o f r e s e a r c h . J o u r n a l o f C h i l d P s y c h o l o g y a n d P s y c h i a t r y , 1 9 6 8 , 9_» 1 - 2 5 . S t o d d a r d , L . T . A n o b s e r v a t i o n o f s t i m u l u s c o n t r o l i n a t i l t d i s c r i m i n a t i o n b y c h i l d r e n . J o u r n a l o f E x p e r i m e n t a l A n a l y s i s o f B e h a v i o r , 1 9 6 8 , 1 1 , 3 2 1 - 3 2 4 . S u t h e r l a n d , N . S . S h a p e d i s c r i m i n a t i o n a n d r e c e p t i v e f i e l d s . N a t u r e , 1 9 6 3 , 1 9 7 , 1 1 8 - 1 2 2 . S u t h e r l a n d , N . S . a n d H o l g a t e , V . Two c u e d i s c r i m i n a t i o n l e a r n i n g i n r a t s . J o u r n a l o f C o m p a r a t i v e a n d P h y s i o l o g i c a l P s y c h o l o g y , 1 9 6 6 , 4 , 1 9 8 - 2 0 7 . T e r r a c e , H . S . S t i m u l u s c o n t r o l . I n W. K . H o n i g ( E d . ) O p e r a n t B e h a v i o r : A r e a s o f R e s e a r c h a n d A p p l i c a t i o n . New Y o r k . A p p l e t o n - C e n t u r y -C r o f t s , 1 9 6 6 , P p . 2 7 1 - 3 4 4 . T r a b a s s o , T . a n d B o w e r , G . H . A t t e n t i o n i n l e a r n i n g . New Y o r k . W i l e y , 1 9 6 8 . W a r d , A . J . E a r l y i n f a n t i l e a u t i s m : D i a g n o s i s , e t i o l o g y a n d t r e a t m e n t . P s y c h o l o g i c a l B u l l e t i n , 1 9 7 0 , 22, 3 5 0 - 3 6 2 . W a r d , A . J . a n d H a n f o r d , H . A . E a r l y i n f a n t i l e a u t i s m : s y n d r o m e , s y m p t o m a n d w a s t e b a s k e t . 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McGraw-Hill, 1963, Pp. 159-223. 66 APPENDIX Wing (1969) conducted a study i n which a u t i s t i c c h i l d r e n were compared wi th normal c h i l d r e n and c h i l d r e n with Down's Syndrome, recept ive aphas ia , executive aphasia and p a r t i a l l y b l i n d , p a r t i a l l y deaf c h i l d r e n . The a u t i s t i c c h i l d r e n were d i v i d e d in to a speaking and a non-speaking group. A l l had been diagnosed a u t i s t i c by two p s y c h i a t r i s t s . The ir v e r b a l behavior was s u f f i c i e n t to i n d i c a t e b a s i c needs i n short phrases such as naming of some common objects and f o l l o w -ing simple i n s t r u c t i o n s . They had no c l i n i c a l l y detectable evidence of b r a i n damage. Although no information was a v a i l a b l e on the chromosomal s t ruc ture of the c h i l d r e n with Down's Syndrome, a l l of the c h i l d r e n were assoc iated wi th mental r e t a r d a t i o n ( I .Q . range: 30-50) and had the t y p i c a l c h a r a c t e r -i s t i c s of mongolism such as short s t a t u r e , o b l i q u e , narrow eyes, a g u t t e r a l vo i ce and poor a r t i c u l a t i o n . Congenita l recept ive aphasia i s an abnormality assoc iated wi th speech comprehension. A l l the c h i l d r e n i n the group were sa id to have p e r i p h e r a l deafness, although t h e i r problem of speech compre-hension was more severe than could be accounted for by t h e i r degree of deaf-ness. Congenital executive aphasia i s a d i sorder assoc iated with speech product ion , not assoc iated with p e r i p h e r a l sensory d e f i c i t . The f i f t e e n c h i l d r e n i n the b l i n d / d e a f group were a l l handicapped with congent ia l ca taract s and deafness, due to maternal r u b e l l a . Only three had u s e f u l v e r b a l behavior . 67 Comparisons between the groups were made by r e t r o s p e c t i v e surveys by means of a questionnaire, that was mailed to parents of s u i t a b l e c h i l d r e n who had l i v e d with them s ince b i r t h u n t i l at l ea s t f i v e years of age. The occupat ional l e v e l of the parents se lec ted , tended to be above average. The quest ionnaire that was sent out to the parents con-s i s t e d of a schedule designed to e l i c i t a h i s t o r y of abnormal i t ies i n development, covering the var ious categories of behavior which are c h a r a c t e r i s t i c of e a r l y i n f a n t i l e autism. The r e s u l t s ind ica ted that a u t i s t i c c h i l d r e n manifested more abnormal responses to audi tory and v i s u a l s t i m u l i than the c h i l d r e n i n the other group, and t h e i r sensory response patterns c l o s e l y resembled that of the p a r t i a l l y b l i n d / p a r t i a l l y deaf group. L i k e the b l i n d / d e a f c h i l d r e n , the a u t i s t i c c h i l d r e n had great d i f f i c u l t y i n understanding gestures , showed abnormal body movements and a preference for exp lor ing t h e i r surroundings wi th t h e i r hands. Some d i f ferences between the speaking and non-speaking a u t i s t i c c h i l d r e n were a l so ev ident , although the d i f f erence was not s i g -n i f i c a n t . A l l of the twenty speaking a u t i s t i c c h i l d r e n were scored as performing w e l l on non-verbal s k i l l s and i n t e r e s t s , whi le only four of the seven non-speaking c h i l d r e n achieved the same high score . Wing suggested that the anomalies i n the a u t i s t i c c h i l d r e n s ' responses to sensory s t i m u l i are d i r e c t l y l i n k e d to t h e i r i n a b i l i t y to communicate as a r e s u l t of t h e i r language problems, and that d i f f i c u l t i e s i n s o c i a l behavior evident i n these c h i l d r e n are to be regarded as secondary to the more bas i c handicaps. 68 T h e r e i s o n e p r o b l e m w i t h W i n g ' s s t u d y a n d t h a t i s t h e b i a s i n h e r e n t i n r e t r o s p e c t i v e q u e s t i o n n a i r e s . I t i s v e r y p r o b a b l e t h a t p a r e n t s o f o l d e r c h i l d r e n w o u l d r a t e f e w e r a b n o r m a l i t i e s f o r t h e p r e - s c h o o l y e a r s , t h a n p a r e n t s o f y o u n g e r c h i l d r e n . A n e x a m i n a t i o n o f t h e a g e d i s t r i b u t i o n o f s u b j e c t s i n W i n g ' s s t u d y i n d i c a t e s t h a t t h e a u t i s t i c g r o u p a n d t h e m o n g o l o i d g r o u p h a d t h e g r e a t e s t n u m b e r o f s u b j e c t s w i t h i n t h e 1 2 - 1 6 y e a r a g e b r a c k e t , w h i l e a s many a s 6 7 % o f t h e d e a f / b l i n d c h i l d r e n w e r e b e t w e e n 4 a n d 5 y e a r s o l d . I n v i e w o f t h i s , t h e r e s u l t s s h o u l d b e i n t e r -p r e t e d w i t h c a u t i o n . R u t t e r ( 1 9 6 8 ) p r o p o s e d t h a t t h e p r i m a r y d e f e c t s i n e a r l y c h i l d h o o d a u t i s m a r e a l a n g u a g e d i s o r d e r a n d i m p a i r m e n t o f s o u n d s . R u t t e r c l a i m s t h a t t h e r e i s a d e q u a t e e v i d e n c e i n s u p p o r t o f t h i s h y p o t h e s i s i n v i e w o f t h e s i m i l a r i t i e s b e t w e e n a u t i s t i c c h i l d r e n a n d t h o s e s u f f e r i n g f r o m s e v e r e d e v e l o p m e n t a l l a n g u a g e d i s o r d e r s , a n d o f t h e i m p o r t a n c e o f l a n g u a g e a s a p r o g n o s t i c f a c t o r . S p e c i f i c a l l y , R u t t e r c i t e s t h e s t u d i e s b y K r a n n e r E i s e n b e r g ( 1 9 5 6 ) a n d C r e a k ( 1 9 6 1 ) i n w h i c h i t w a s f o u n d t h a t b a d p r o g n o s i s w a s a s s o c i a t e d w i t h a p r o l o n g e d f a i l u r e i n s p e e c h d e v e l o p m e n t . T o t e s t h i s h y p o t h e s i s , R u t t e r c o n d u c t e d a m a s s i v e f i v e t o f i f t e e n y e a r f o l l o w - u p s t u d y o f 6 3 p s y c h o t i c c h i l d r e n a n d 6 1 c o n t r o l c h i l d r e n ( 1 9 6 7 a , 1 9 6 7 b ) . T h e b e h a v i o r a l d e s c r i p t i o n o f t h e p s y c h o t i c c h i l d r e n c l o s e l y c o n f o r m e d t o t h e d i a g n o s t i c c r i t e r i a o f e a r l y c h i l d h o o d a u t i s m , a n d a n u n e q u i v o c a l d i a g n o s i s o f t h e s y n d r o m e h a d b e e n a g r e e d b y a l l t h e c o n s u l t a n t p s y c h i a t r i s t s a t t h e M a u d s l e y H o s p i t a l . T h e p s y c h o t i c a n d n o r m a l c h i l d r e n w e r e c l o s e l y m a t c h e d f o r I . Q . , a g e a n d s e x . 69 The mean age at which the c h i l d r e n were f i r s t observed was s i x years and the mean age when examined at fol low-up was 16 years . At the beginning of the study, each c h i l d was given a n e u r o l o g i c a l and p s y c h i a t r i c examination. The c h i l d r e n were a lso observed i n an u n -s tructured s i t u a t i o n with other c h i l d r e n and with adul ts at home, school or h o s p i t a l . A d e t a i l e d d e s c r i p t i o n of the c h i l d ' s past and present behav iora l and s o c i a l s ta tes , together with an account of i l l -ness and other medical information of the hea l th of the re s t of the f a m i l y , were obtained from the parent or p a r e n t - s u b s t i t u t e us ing a standard interv iew schedule. Spec i f i ed behaviors were rated on a f i v e -point s c a l e . S i m i l a r tes t s and interviews were conducted when the sub-j e c t s were re-examined at the end of the fol low-up p e r i o d . At the time of fo l low-up , informat ion concerning the subjects ' admin i s t ra t ive p l a c e -ment, the amount of school ing they had rece ived and progress at schoo l , p s y c h i a t r i c and medical treatment and developmental course of i n d i v i d u a l behav iora l c h a r a c t e r i s t i c s were obtained. The r e s u l t s i n d i c a t e d that the c h i l d who was not speaking by age f i v e or who manifested a profound lack of response to sounds i n e a r l y ch i ldhood , was l e s s l i k e l y to achieve a normal or near normal l e v e l of s o c i a l adjustment at a l a t e r stage, than would a c h i l d who, at the age of f i v e , could speak and respond to sounds normal ly . Rutter found that the s o c i a l outcome of the psychot ic c h i l d r e n at fol low-up was s i g n i f i c a n t l y worse than that of the c o n t r o l c h i l d r e n . He a t t r i b u t e d t h i s d i f f e r e n c e i n outcome between the two groups, to the language d i sorders of the psychot ic 70 c h i l d r e n . Unfortunate ly , the major i ty of the c o n t r o l c h i l d r e n had some degree of mental subnormality and i n many cases the r e t a r d a t i o n was accompanied by impairments i n speech. Rutter gives no explanat ion for the be t t er s o c i a l outcome of the c o n t r o l group i n sp i t e of t h e i r speech d i s o r d e r s . This diminishes the strength of R u t t e r ' s argument that language d i sorder i s the primary abnormality i n e a r l y chi ldhood autism and that prognosis i s p r i m a r i l y assoc iated with speech development at an e a r l y stage. The argument that the bas i c defect i n e a r l y chi ldhood autism i s language d i sorder seems more tenuous when one reviews the vast body of l i t e r a t u r e on deaf c h i l d r e n . Furth (1966, 1973), for example, has s u f f i c i e n t l y demonstrated that deaf c h i l d r e n can perform as w e l l as normal c h i l d r e n i n most non-verbal tasks . Furthermore, the language hypothesis has d i f f i c u l t y exp la in ing why s o c i a l withdrawal does not accompany deafness, although i t i s pos s ib l e that the aloofness i s l e s s obvious i n deaf c h i l d r e n because t h e i r handicap was detected at an e a r l y age and a remedial program introduced immediately a f t e r . 

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