Cognition, 43 (1992) 225–251 Domain specificity in conceptual development: Neuropsychological evidence from autism* Alan M. Leslie and Laila Thaiss MRC Cognitive Development Unit, University of London, 17 Gordon Street, London WC1H OAH, UK Received March 10, 1990, final revision accepted January 10, 1992 Abstract Leslie, A.M., and Thaiss, L., 1992. Domain specificity in conceptual development: Neuropsychological evidence from autism. Cognition, 43: 225–251. To understand some aspects of conceptual development it is necessary to take cognitive architecture into account. For this purpose, the study of normal develop- ment is often not sufficient. Fortunately, one can also study neurodevelopmental disorders. For example, autistic children have severe difficulties developing certain kinds of concepts but not others. We find that whereas autistic children perform very poorly on tests of the concept, believes, they are at or near ceiling on comparable tasks that test understanding of pictorial representation. A similar pattern was found in a second study which looked at understanding of a false map or diagram: normal 4-year-olds showed a marked advantage in understanding a Correspondence to: Alan M. Leslie, MRC Cognitive Development Unit, University of London, 17 Gordon Street, London WC1H OAH, UK *Parts of this work were presented in talks by the first author to the VIIIth European Workshop on Cognitive Neuropsychology, Bressanone, Italy, January 1990, to the Department of Psychology, University of Chicago, June 1990, and to the Conference on Cultural Knowledge and Domain Specificity, University of Michigan, Ann Arbor, October 1990. Our thanks to Daniel Roth, Simon Baron- Cohen, John Morton and Uta Frith for comments on an earlier draft, and to Jon Bartrip for help with data analysis. We are also grateful to the children and staff of Doucecroft School, Harborough School and Whitefield School for their assistance in these studies. Editor: This article should have appeared in Cognition volume 40, number 3, together with the article by Leekam & Perner entitled “Does the autistic child have a metarepresentational deficit?”. Unfortunately, an administrative error made this impossible and delayed the appearance of the present article. We apologize for this mistake. 0010-0277/92/$8.60 © 1992 – Elsevier Science Publishers B.V. All rights reserved.