Atypical categorization in children with high-functioning autism spectrum disorder.

Children with autism spectrum disorder process many perceptual and social events differently from typically developing children, suggesting that they may also form and recognize categories differently. We used a dot pattern categorization task and prototype comparison modeling to compare categorical processing in children with high-functioning autism spectrum disorder and matched typical controls. We were interested in whether there were differences in how children with autism use average similarity information about a category to make decisions. During testing, the group with autism spectrum disorder endorsed prototypes less and was seemingly less sensitive to differences between to-be-categorized items and the prototype. The findings suggest that individuals with high-functioning autism spectrum disorder are less likely to use overall average similarity when forming categories or making categorical decisions. Such differences in category formation and use may negatively impact processing of socially relevant information, such as facial expressions. A supplemental appendix for this article may be downloaded from http://pbr.psychonomic-journals.org/content/supplemental.