The content boundaries of natural categories in high-functioning young adults with autism spectrum disorders

The present study evaluated the functioning and structuring of semantic knowledge for naturalcategories in Autism Spectrum Disorders (ASD). A sample of high-functioning adults (HFA) withASD (n = 20) and a sample of typical developed individuals (n = 20) (matched for age, education,and verbal IQ) performed two tasks with natural concepts: a task of semantic access from pictures(the Camel and Cactus test) and a semantic matching-to-sample task, designed to evaluate category boundaries and structure. Overall, the HFA group showed preserved access to conceptual knowledge but some irregularities in category structure as reflected by the increased in typical errors found in the matching-to-sample task. This pattern of under generalization is suggestive of categories that have an abnormal and restricted content, missing out the typical instances.