social cognition in developmental language disorders and high-level autism

SOCIAL COGNITION IN DEVELOPMENTAL

AUTISM LANGUAGE DISORDERS AND HIGH-LEVEL

Jane Shields Roseinan, Vurley Priul Broks Adrian Sirripson

Autism is a developmental condition involving a triad of social impairments: in social relationships, communication, and imagination (Wing and Gould, 1979). Rapin and Allen (1987) commented that one subtype of developmental language disorder - ‘semantic-pragmatic syndrome’ - was frequently seen, in a severe form, in verbal children with autism. In children with ‘semantic-pragmatic’ disorder, the onset of language use is delayed, and when language emerges i t is accompanied by echolalia, jargon and auditory inattention. When they are older, such children use superficially complex language with clear articulation but have difficulty with the use and understanding of language, interpreting over-literally and using language inappropriately in conversation. There has been debate as to whether semantic-pragmatic language disorder forms part of the disorders of the autistic spectrum.

Language has canonical components such as phonology, syntax and lexical semantics. but other non-componential. non-literal and context-bound aspects of language are involved in its use in social discourse. The exercise of these pragmatic language skills relies upon the integrity of broader cognitive functions concerned with the processing of social information. Language use also involves the broader skills of attention aNd draw- ing inferences. s

The study of social cognition has been concerned both with the nature of social knowledge and with the nature of cognitive processes involved in the perception and interpretation of the social world (Ostrom 1984). It has been suggested that the social impairments found in autism are linked to an inability to mentalise, a lack of understanding of mental states: of a ‘theory of mind’ (Baron-Cohen 1989. Frith 1989).

Brothers (1990. 1992) proposed a specific brain system for social cognition, defining the end result of social cognition as the accurate perception of the disposi- tions and intentions of other individuals. From accumulated work with primates, Brothers identified three brain areas which are important for social cognition: the amygdala, the superior temporal sulcus, and the orbital-frontal cortex.

Hetzler and Griffin (1981) favoured bilateral temporal dysfunction as the underlying cause of autism. and Damasio and Maurer ( 1978) proposed bilateral dysfunction in structures including the ring of mesolimbic cortex. Kluver-Bucy syndrome (resulting from bilateral induced lesions of the amygdala and infe- rior temporal cortex) has been cited as a neurological model of autism (Damasio and Maurer 1978). Bachevalier ( I99 1 ) found impairments of social interaction in monkeys with bilateral lesions of the amygdala and hippocampus. Bishop

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TABLE 1 Subject characteristics

Groiip hecrr4~eSD Hmcledrress Sex Socio- Ecoaornic Srorirs' Riglrr LeJ Rorrge M ode

S 105.9 19.78 9 1 10 0 I 4 2 P 104.4 19.44 9 1 10 0 14 2 A 108.9 18.54 8 2 9 1 1 4 2 C 106.3 19.84 8 2 5 5 I4 2

'Socio-economic status (as defined by thc Office of Population Censuses and Surveys): 1 =professional erc occupations, 2 = intermediate occupations, 3(N) = skilled occupations. non-manual. 3(M) = skilled occupations, manual. 4 =partly skilled occupations, 5 =unskilled occupations. S = Semantic-pragmatic, P =Phonologic-syntactic. A =high-level autism, C=controls (normal).

(1993). in a review paper, suggests that the limbic system and associated frontal lobe structures may well contribute to the neurobiological basis of autism.

In a related study (Shields et nl. 1996) we have found evidence of neuro-

. psychological similarities between semantic-pragmatic language disorder and high-level autism. Groups of children with these two disorders had similar pat- terns of results in neurological tests indicative of right hemisphere functional deficiency.

The aim of this study was to furthcr clarify this link by examining some aspects of social cognition in groups of children with 'phonologic-syntactic disorder' (P); and 'semantic-pragmatic disorder' (S); in a group of children with high-level autism (A); and in a control group of normal children (C).

Our hypothesis was that the groups with semantic-pragmatic language disorder and with high-level autism would perform poorly on the tests of social cognition.

Method S u BJ ECTS Four groups of 10 children in the age range 7 to 1 1 years participated in the study. The groups are described in more detail in the companion paper (Shields ei d. 1996). Of the two groups with language impairment, one (P) had a disorder of language form (phonology and syntax) and one (S) had semantic and pragmatic difficulties. These two groups were

recruited and constituted as described in the companion paper (Shields et 01. 1996). and their communication symp- toms were rated as described there, using Rapin and Allen's (1987) criteria for 'phonologic-syntactic syndrome' and 'semantic-pragmatic syndrome'. They all had special educational needs and were being educated in facilities for children of normal intelligence. None was known to have signs of brain pathology. None had been diagnosed as having autism.

Another group (A) comprised children with high-level autism according to DSM-III-R criteria.

A group of control subjects (C) comprised normal children, from the same area.

As described in the companion paper, age was controlled by matching across the four groups, each set of four subjects being within 9 months of age of each othcr. The groups were also matched for socio-economic status. None of our subjects with language disorder were girls, reflecting the greater prevalence of developmental language disorder in boys (Erne 1979). Since those tests which had norms had been standardised on groups of boys and girls, we selected a control group of boys and girls. Subjects' details are given in Table I.

PROCEDURE Each subject was tested individually by the first author in their own school or home. Tests of social cognition included social comprehension questions,

theory-of-mind procedures and a test to detect eye direction. Details of the con- tents of the test battery are given in the Appendix.

Results

We predicted that groups S and A would perform less well than groups P and C. This prediction was tested by profile analysis (Morrison 1990, Johnson and Wichern 1992) to discover whether there were general differences between the groups, followed by more specific between-group comparisons. All data were rendered commensurable by c.on- version to percentages if necessary.

STATISTICAL TREATMENT OF DATA

Tests on assru~tptions With sample sizes as small as 10, tests on assumptions were unlikely to give very clear conclusions. Furthermore, in 14 of the 16 samples, an appreciable number (between three and eight) of the observations were tied. This was particularly true of the Eye Direction Detection test, where at least half the observations were tied in each of the four samples. If one attempts to test for univariate normality by computing Pearson correlation co- efficients, r. from quantile-quantile plots of the ordered scores ve):siis standard normal quantiles, as suggested by Johnson and Wichern (1992). misleadingly high values of I’ are obtained as a result of the ties. Therefore, in view of the small sample sizes and numerous ties, tests on univariate normality could not yield useful information. Furthermore. the ties would remain even if the data were transformed, e.g. to logits, in an attempt to seek data likely to conform better to normal distributions.

The equality of the covariance matriccs was evaluated using the test devised by Box (1950). The limitations of using this procedure in our study are explained else- where (Shields et 01. 1996). Box’s statistic distributed as F was computed in addition to the more usual x’ statistic. F was significant at a level ofp=0.0001 and x’ at pc0.025, suggesting that equality of covariance matrices could probably not be assumed.

Since parametric multivariate analyses were probably inappropriate in this con-

ITi 3. rt I r’ X rt

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text (Shields et 01. 1996), we decided to use randomisation tests (Edgington 1980, Manly 1991) as the basis of the analyses.

x Such an approach would still enable mul-

sis. to be computed, but would overcome f the problem of violation of parametric

5 c assumptions by establishing significance 2

by randomisation. 2

Profile niinlysis - 5,

of profile analysis (Morrison 1990) based

tivariate analyses. such as profile analy-

c

- - - 2 \

Test statistics were computed for a form

on the two-way mixed-model analysis of variance (ANOVA). In our randomisa- < tion version of this test, the significance of the computed F ratios was determined by relating them to their randomisation distributions using Manly’s (1991) ‘two-

involving both an independent-samples 5

\ - - - “ -

‘> ”

.; < 2 - - ” - - - - - 3 > stage’ randomisation method for a design

factor and a repeatcd-measures factor. In this and in all the other randomisation tests described below, the randomisation distribution was established from 9999 random permutations of the data plus the actual data set.

Running the randomisation test on the ANOVA version of profile analysis, we found significance levels of pc0.0001 for the Groups effect, pc0.0001 for the repeated-measures (Tests) effect and p=O.O172 for the interaction (Parallelism) effect. We could not conclude that the profiles were parallel (as shown by the third significance level) and there was therefore some doubt about the scope of the first result that the groups differed significantly. The significance of the repeated-measures effect will be ignored, because differences between the mean scores across the tests are not of interest. I t was therefore necessary to examine the individual tests in the battery separately.

The graph of the profiles (Fig. 1 ) showed clearly that’the S and A groups were approximately coincident, and that their mean results were below those of the P and C groups. as predicted. The size of this difference varied across the tests in the battery. being particularly strong for the Theory of Mind and Social Comprehension B tests.

To examine differences between the groups within each of the four tests separately. F statistics from individual one-

-

489

490

100

90

80

70 C

860 3

850

40

30

20

10

- 0 - P + s 4 A

+ C

TABLE I I Right hemisphere battery: one-way ANOVAs

Test

Theory of Mind 26. I3 <0.000 1 Eye Direction Detection 5.21 0.0039 Social Comprehension W' 16.66 <o.ooo I Social Comprehension B' 14.06 <o.ooo I

I From the Wechsler Preschool and Primary Scale of Intelligence Verbal Comprehension subtest (Wcchsler 1967)

From the British Ability Scales Social Comprehension subtest (Elliott et trl. 1977)

factor independent-samples analyses of variance were computed in randomisation tests. They gave the results presented i n Table 11.

Modified Fisher PLSD tests on individual comparisons gave the results presented i n Table 111. Again a randomisation process based on F statistics was employed for each comparison

between means. Asterisks to indicate statistical significance were attached only if the p value was less than a critical value derived from application of the Bonferroni inequality. excluding comparisons for which the means were not expected to differ. This gave 1' = 0.0514 = 0.0125 as the critical 11 value. The comparisons between P and C, and between S

TABLE 111 vi

Two-tailed p values ? F' m c2

(c.

0 0

26

d Test f v s s P v s A P v s C S V S A S v s C A v s C

Theory of Mind 0.005' 0.0003x 0.0241 0.7588 O.OOOI^ 0.0001" - Eye Direction Detection 0.02082 0.01 18" 0.6298 0.6303 0.0255 0.0158 5.

Social Comprehension B 0.0037* 0.0045" 0.3095 1 .000 0.0002* 0.0008 $ r is' 3

One-tailed p values - Y

g s

'c b \

Social Comprehension W 0.001 2< 0.0020* 0.0394 0.26 I2 0.OOO I * 0.0002*

- -- *p=0.0125; sec text for discu\sion. s

TABLE IV - .-

Test P v s S P v s A P v \ C S v s A S v s C A v s C " : Theory of Mind 0.0005" 0.0003 0.000 1 * 0.0001 " - "

Social Comprehension W 0.0009* 0.0007" 0.000 1 * 0.000 1 - z Social Comprehension B 0.0017* 0.0025* O.o002* 0.00024 L 6

- 0.01 18* 0.0088* 5 Eye Direction Detection 0.0146 0.0056"

y'p=0.0125; see text for discussion.

TABLE V Comparison of P+C with S+A

Test One-toiled Two-tailed

Theory of Mind 0.0001 o.Oo0 1 Eye Direction Detection 0.0001 0.0002 Social Comprehension W 0.0001 0.000 1 Social Comprehension B 0.000 I 0.000 1

and A, are included in the table merely to show that, if one tests these differences against the same criterion, they arc not significant. However, there would be some evidence. if one adopted the 0.05 'per comparison' error rate, that groups P and C differed significantly on two tests.

Where a difference had been predicted, its direction had also been predicted. We could therefore employ one-sided significance tests for the four sets of predicted differences. Table IV assesses the one- sided significance levels. against the Bonferroni p value of 0.0125. Since no predictions about differences were made for the P-to-C and S-to-A comparisons. one-sided tests were not computed in these cases. All but one of the one-tailed values were deemed 'significant' on this criterion. In a few cases the one-tailed values did not differ from two-tailed for

technical reasons associated with the randomisation tests.

The most direct test of the prediction that groups S and A should do less well than groups P and C (which overcomes the disadvantage that comparisons between tests are not independent) was to compute specific contrasts between the S and A groups combined, on the one hand, and the P and C groups combined, on the other. The results of randomisation tests, using F statistics, of these contrasts are presented in Table V. (Although one- and two-sided p values are both given, the p values are so low the distinction hardly matters.)

The results of these specific comparisons were very clear. The combined P and C sample consistently, and very significantly, did better than the combined S and A sample. 491

C .-

492

Discussion Clear support was found for the hypothesis that thc groups with semantic-pragmatic language disorder and with high-level autism would both do poorly on tests of social cognition. Phonologic-syntactic language disorder may be associated with immature theory- of-mind skills: or the lower score of group P v s group C may result from the demands made by this task on language- comprehension skills. However, i t is clear that semantic-pragmatic language disorder and high-level autism involve a severe deficit in this area.

The significant diffcrences between groups S+A and groups P+C for social cognition tasks support the opinion that 'semantic-pragmatic disorder' is a disorder of the autistic spectrum and that the weaknesses in communicative compe- tence in children with the disorder may result from, or be associated with, an underlying cognitive deficit which is not primarily linguistic in nature.

The results of this and the parallel study (Shields et al. 1996) link semantic-pragmatic language disorder and high-level autism in two ways: first, the two groups share a pattern of results indicative of right hemisphere functional deficiency (e .g . poor performance of visual and visuo-constructional tasks); second, they share a pattern of results indicative of social-cognitive dysfunction. It is worth considering briefly how these findings might be accommodated in neuropsychological terms.

There have previously been sugges- tions that autism can be characterised as a disorder of the right hemisphere (Sarvis 1960, Fein er (11. 1984. Goodman 1989). With regard to the 'right hemisphere battery' of tests, the results of the first study (Shields et cil. 1996) appear to fit with this notion. However, there has also been speculation over many years that abnormalities of frontal lobe and/or limbic structures may lie at the root of autistic disorder, a view that has gained favour in recent years. Bishop (1993) argues per- suasively that the notion of frontal lobe and limbic system dysfunction provides the most promising working hypothesis not only in terms of the search for neurobiological correlates of this disorder but

also in providing insight into the range of psychological impairments characteristic of the condition. As an example of the convergence of psychological and neurobiological thinking. Baron-Cohen and Ring (1994) hypothesise that the core cognitive deficits of autism may be traced to neural circuitry encompassing the superior temporal sulcus. the orbitofrontal regions and the amygdala. Such speculation is in line with the view of Brothers (1990), who has proposed that there is a specific brain system responsi- ble for mediating social cognition, which incorporates the amygdala (concerned with the regulation of emotional response), the superior temporal sulcus (concerned with various aspects of face perception), and the orbitofrontal cortex (concerned with the regulation of behaviour within social contexts).

It is interesting to speculate on whether the pattern of results observed for the semantic-pragmatic and autistic groups in the two studies might be accommodated in terms of abnormalities within this proposed neural circuitry. We suggest that the present results could be explained, at least in part, by abnormalities restricted to the amygdala, arguably the key component of the hypothesised brain system in view of its rich intercon- nectivity with frontal and temporal regions as well as with subcortical structures concerned with autonomic and endocrine functions underlying emotional response (Amaral et al. 1992). In recent years a picture of the cognitive consequences of damage to thc amygdala has begun to emerge and the reported effects of restricted bilateral amygdala lesions in humans bear some similarity to the profile of results reported for the semantic-pragmatic and autistic groups in the present study. For example, specific impairments of visual memory and face processing have been observed in the context of preserved canonical language skills (Jacobson 1986, Tranel and Hyman 1990, Adolphs et 01. 1994, Allman and Brothers 1993. Young et 01. 1995). Allman and Brothers noted the possible relevance of such studies to the understanding of autism, and there had already been some suggestion that the Kluver-Bucy syndrome (which depends

critically upon bilateral amygdala damage) carries parallels with autism (Damasio and Maurer 1978). In the light of the present observations, the comparison of autistic cognitive functions and deficits associated with acquired arnyg- dala damage promises to be a fruitful line of inquiry.

Our studies illustrate both strengths and limitations of the neuropsychological approach. Comparison of test profiles across different types of developmental and acquired cognitive disorder serve to highlight points of convergence and suggest common underlying neurological abnormalities, but the tests themselves lack the power to indicate definitively which brain systems may be involved (the amygdala system, or right neocorti- cal areas). However, by bringing candi- date brain systems into view, neuropsychological studies give direction to neuropathological studies. The way forward in understanding the neurological basis of developmental disorders is likely to involve a combination of neuropsychological and neuropathological methods, including structural and functional brain imaging.

In conclusion, our data are consistent with a notion of right hemisphere dysfunction as a contributor to both semantic-pragmatic language disorder and autism, but it is possible that this reflects abnormalities within a more complex functional-anatomical system. perhaps involving the amygdala.

Appendix TESTS OF SOCIAL COGNITION: SCI - Theory of Mind (Wimmer and Perner 1983, Baron-Cohen er al. 1985. Perner and Wimmer 1985, Baron-Cohen 1989. Perner ef nl. 1989, Happe 1991):

r, tests of first- and second-order false 0 7 belief and deception, which assess the

ability to mentalise - to appreciate the content of other people’s thoughts and beliefs. The skill of mentalizing develops with age in normal children, but is weak in children with autism. SC2 - Eye Direction Detection (Baron- Cohen 1992): a technique for assessing

2 the perception of gaze in the comprehension of mental states. Children with < autism find this hard and tend to give egocentric responses. SC3 and SC4 - Social comprehension (W and B): questions from the Wechsler Preschool and Primary Scale of s Intelligence Verbal Comprehension sub-

British Ability Scales Social 3

*

test, which tap social cognition. Norms 5

P- oc 3

rc. 26

E - 5.

z - cr. L - - 5

- * L, \ - - - Y - - .- ”

2, - - test (Wechsler 1967), and from the.

Comprehension (Elliott et cil. 1977) sub-

were not used, but children in the age range involved should find these questions easy, whereas children with autism have difficulty with such tests (Frith 1989).

Accepted jor pitblrccirrari I t i Airgictr. 1995.

Arir/ior.s ’ Apporr1rrrrt.rrr.s ’Jane Shields. MPhil. PhD. DipCST. AIL. Speech and Language Therapist. Storm House School. National Autistic Society. UK. Rosemary Vmley. BSc. MA. PhD. Lecturcr. Speech Sciences: Adrian Simpson BA, PhD. Lecturer. Department of Psychology; University of Sheffield. Paul B r o k BA. MSc. DPhil. CPsychol. Senior Lccturer. School of Psychology. University of Birmingham.

- ” - - * >

Acl;rio~clerl~errrerirs The authors acknowledge rhc help of Simon Baron- Cohen and Franccsca Happe in devising the test battery used. They also thank the subjects who participated. and their parents. therapists and tcach- ers.

“Corrcspoirderice to, jirsr crrrllior at Priory Annexe: Storm House School. St Wilfred’s Road. Cantley. Doncasier DN-I 6AH. UK.

SUMMARY Two groups of children with contrasting types of developmental language disordcr (phonologic-syntactic and semantic-pragmatic) were compared with a group of children with high- level autism and with a control group of normal children on tests of social cognition (theory of mind; social comprehension; and detection of eye direction), The similarly poor performances of the semantic-pragmatic group and the autistic group suggest that semantic-pragmatic language disorder lies on the autistic spectrum.

RESUME

(phonologique-syntaxique et simantique-pragmatique) ont ete compares B un groupe d’enfants

Corrrmisserrrce socinle dmrs Ies troirbles ~~i.elopperrrerrtarr.r elir Irrrgage et I ‘ourisme cle lrcrrrt rri\.eorr Deux groupes d’enfants avec des types contrastants de trouble developpemental du langage

493

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avec autisme d e haut niveau et avec un groupe contr8lc d'enfants normaux sur des tests d e connaissance sociale (thtiorie de I'esprit; comprehension sociale; et detection d e la direction oculairc). Des performances egalement pauvres dans le groupe semantique-pragmatiquc e t le groupe autistique suggbrent que le trouble du langage de type semantique-pragmatique appartient au spectre d e I'autisme.

ZUSAMMENFASSUNG Sozitrle Fiihigkeiterz bei erif~i~icklrrngshedirlglerr Sprctchsrorroigeri rind hocirgradigem Airtisrrzirs Zwei Gruppen von Kindern rnit verschicdenen entwicklungsbedingten Sprachstorungen (phonologisch-syntaktisch und semantisch-pragmatisch) wurden rnit einer Gruppe von Kindern mit hochgradigem Autismus und mit einer Kontrollgruppe gesunder Kinder anhand von Tests zur E r f w u n g sozialer Fshigkeiten (Theory of Mind. soziales Vers thdn i s und Festlegung der Blickrichtung) verglichen. bie Phnlich sch1echten:Ergebnisse de r semantisch-pragmatischcn Gruppe und der autistischen Gruppe lassen vermuten. daR die semantisch-pragmatische Sprachstorung im autistischen Spektrurn liegt.

RESUMEN Cogiiiciori so cia^ err /us alteraciories deI rlesnrroito deI Ierigiiaje y nirtisrrio de ~ I t o iiivel Dos grupos d e nitios d e tipos contrastados d c altcracion del dcsarrollo del lenguaje (fonologico-sintiictico y semiintico-pragmitico) fueron comparados con un grupo d e niitos con autism0 d e alto nivel y con un grupo control d c niiios normales. utilizando prucbas d e cognicidn social (teoris d e la mente. comprension social y deteccion d e la direccion ocular). La similitud d e 10s pobres resultados en.el grupo semlntico-pragmiitico y en el autistico sugieren que la alterici6n sernintico-pragmitica del lenguaje esti situada en el espectro autistico.

Refrrerrces Adolphs R, Tranel D. Damasio H. Damasio A.

(1994) Impaired recognition of emotion in facial expressions following bilateral damage to the human amygdala. Ncrrrrre 372: 669-72.

Allman J, Brothcrs L. (1994) Faces. fear and the amygdala. Ncrrirre 372: 61 3 4 .

Aniaral DG. Price JL. Pitkanen A. Carmichael ST. (1992) Anatomical organistion of the primate amypdaloid complex. In: Aggleton JP. editor. Tlre Anrygddti: Nerrrobiological Aspecrs of Orroiiori. Meriron. tirid Merrrcrl D~.sfrrtcfiorr. New York: Wiley-Liss. p 1-66.

Bachevalier J. (1991) An animal model for childhood autism: memory loss and socioemotional dis- turbances following neonatal damage to the limbic system in monkeys. In: Tamminga CA. Schulz SC. editors. Advcrirces iri Nerrrops~clricirr? cirrd Ps~clroplirirrriocolog!. 1: I 2 9 4 0

Baron-Cohen S. (1989) The autistic child's theory of mind: the case of specific developmental delay. Jvirrrrcil of Cliiltl Psycliology cirid Ps~chicrrr-\. 30:

- (1992) Are children with autism blind to the men- talistic significance of the eyes? Poper giver, nr a riieerirrg of rlre Bririslr Nerirops?.clrologicci/ Sricier~. Qireetr Sqimre. Loiidorr. 3rd Noverrrber. 1992.

- Leslie AM. Frith U. (1985) Does the autistic child have a 'theory of mind"? Cogtiiriorr 21: 37-46.

- Ring H. ( 1994) A model of the mind reading system: neuropsychological and ncurobiological per- spectives. In: Mitchell P. Lewis C. editors. Origirrs of ciri Urtdrrsrciridirrg of Mirid. Hillsdale, New Jersey: Lawrence Erlbaum Associates.

Bishop DVM. ( 1993) Autism. executive functions and theory of mind: a neurological perspective. Joirrrial of Clrild P.ycholog~ crrid Psxclritrrn 34: 279-93. (Annotation).

Box GEP. ( 1950) Problems in the analysis of growth and wear curves. Bioaietrics 6: 362-89.

Brothers L. (1990) The social brain: a project for. integrating primate behaviour and neurophysiol- ogy in a new domain. Corrceprs irr Neitroscierrce 1: 27-5 I

- ( 1992) Perception of social acts in primates: cog- nit ion and neurobiology. Serrrirrcirs in /lie

285-98.

Ncrrrcrscierrces 4: 409- 14. Dainasio' AR. Maurer RG. (1978) A neurological

model for childhood autism. Archives of Neirrcilog~ 35: 777-86.

Edginton ES. ( 1980). Roridvnii:trriori Tesrs. New York: Dekker.

Elliott CD. Murny DJ. Pearson LS. ( 1977) British Abilirx Scoles. Windsor: NFER-Nelson.

Erne RF. (1979) Sex differences in childhood psy- chopathology: a review. Psyhologicnl Review 86: 574-95.

Fein D. Humes M. Kaplan E, Lucci D. Waterhousc L. (1984) The question of left hemisphere dysfunction in infantile autism. Psychologicol Birllerirr 95: 258-81.

Frith. U. (1989) Aiirisrrr - expluiriirig the errigrrro. Oxford: Basil Blackwell.

Goodman R. (1989) Infantile autism: a syndrome of multiple primary deficits? Jorrrrinl of Airri.srri nrid Der*elopirrerr~d Disorders 19: 409-24.

Happe FGE. (1991) Theon of Mirid ond Corrirtirtrriccrriorr irr Atrrisor (Thesis). University of London.

Hetzler BE, Griffin JL. (1981) Infantile autism and the temporal lobe of the brain. Jormrtrl of Aurisrtl cirrd Det~eloprrreritcil Disorders 11: 3 17-30,

Jacobson R. (1986) Disorders of facial recognition. social bchaviour. and affect after combined bilateral amygdalotomy and subcordate tractotomy: a clinical and experimental study. Psychological Medicine 16: 439-50.

Johnson RA. Wichern W. (1992) 'Applied Mirltivrrriore Srcirisricnl Arial~sis. 3rd ed. Englewood Cliffs: Prentice Hall.

Manly BFJ. ( 1991 ) Raridoriii:ririorr arid Morrre Ccirlo Merlrocls irr Biology. London: Chapman and Hall.

Morrison DF. ( 1990) Midriiwricire Stcirisricrrl Methods. 3rd ed. New York: McGraw-Hill.

Ostrom TM. (1984) The sovereignty of social cognition. In: Wyer RF. Skrull TK. editors. HoridDook vfSocinl Cogiririorr. Vol. I . Hillsdale. New Jersey: Lawrence Erlbaum Associates.

Perner J. Frith U. Leslie AM. Leekam SR. (1989) Exploration of the autistic child's theory of mind: knowledge. belief and communication. Child Deivlopnrrrir 60: 689-700.

Perncr J. Wimmer H. (1985) John thinks that Mary thinks that ... : attribution of second order beliefs by five to ten year old children. Joiirriril of E,vperi~~re~ild Child Psycl~ology 39: 437-7 I .

Rapin 1. Allen DA. (1987) Developmental dysphasia and autism in preschool children: characteristics and subtypes. Proceedings of tlre . Firsr liirerrioriorrtil Syiiiposiiiitr, Specific . Speech triid Driigrcrige Di.rorders i i i Childreii. Uiiiversiry, o/ Reridirig. Eiiglrrrirl.

Sarvis. MA. (1960) Psychiatric iniplications of tcm- poral lobe damage. P.$~clrotrtitil~ric Slr& r / rlre

Shields J. Varley R, Broks P. Simpson A. (1996) Hemispheric funcuon in dcvelopmental language disorders and autism. De~~elopiiiei~rcil Medicine ,

ririd Clrild Nerirology 38: 473-86. Tranel D, Hyman BT. (1990) Neuropsychological.

' Cliill 15: 454-8 I .

corrclates of bilateral amygdala damage. Arc1rii~e.s of Neiirology 47: 349-55.

Wechsler D. ( 1967) Weclisler Pre-school and 'Prirnrin Scule of liirelli~errce. New York: Psychological Corporation.

Wimmcr H, Perncr J. (1983) Belicfs about belief: reprcsentation and the constraining function of wrong bclief in young children's understanding of deception. CoXriiiiori 13: 103-28.

Wing L. Gould J. (1979) Severe impairments of social interaction and associated abnormalities in childrcn: epidemiology and classi tication. Joirrrid c$Arrrisiti mid De~~lc~p i~ ier~rc~ l Disorders 9: I 1-30.

Young AW. Aggleton JP. Hellawell DJ. Johnson M, Broks P, Hanky JR. (1995) Face processing impairments after amygdalotomy. Brriiii 118: 15-24.

x rc.

5 2 5

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social cognition in developmental language disorders and high-level autism

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