Pii: S0010-0277(00)00069-x

In this paper we argue that there are two distinct components of a theory of mind: a socialcognitive and a social-perceptual component. Evidence for this proposal is presented from various sources, including studies of children with Williams syndrome, a rare genetic neurodevelopmental disorder. Earlier work has demonstrated that people with Williams syndrome appear to be spared in the social-perceptual component of a theory of mind. In this paper we present evidence that they are not spared in the social-cognitive component of theory of mind. Three experiments with young children with Williams syndrome were conducted. In each experiment the children with Williams syndrome were compared to age-, IQ-, and languagematched children with Prader±Willi syndrome, and children with non-speci®c mental retardation. The experiments used different measures of theory of mind ability, including false belief (Experiment 1), explanation of action (Experiment 2), and recognition of emotional expressions (Experiment 3). In none of these experiments did the children with Williams syndrome evidence superior performance compared to the control groups. The results from this and other studies on Williams syndrome support the view that the social-cognitive and social-perceptual components of a theory of mind are dissociable. In Williams syndrome only the latter components, which are linked to distinct neurobiological substrates, are spared. q 2000 Elsevier Science B.V. All rights reserved.