The conceptual basis for referential word meaning in children with autism.

The purpose of this study was to examine the nature of the representation of substantive word meanings in children with autism. The subjects included 3 groups of autistic, mentally retarded, and normal children, who were matched on verbal mental age. The subjects participated in 2 experiments investigating their comprehension of words for basic level and superordinate level categories. The 3 groups were equivalent in their performance in both experiments. They also showed the same patterns of overextension and underextension errors that were related to a prototype representation of the underlying concepts. These findings suggest that semantic knowledge for concrete objects is represented and organized in similar ways in autistic, retarded, and normal children and that previous findings on cognitive deficits in autistic children are more likely related to their inability to use cognitive representations in an appropriate and flexible manner.