Cognitive differences in pictorial reasoning between high-functioning autism and Asperger's syndrome.

We investigated linguistic and visuospatial processing during pictorial reasoning in high-functioning autism (HFA), Asperger's syndrome (ASP), and age and IQ-matched typically developing participants (CTRL), using three conditions designed to differentially engage linguistic mediation or visuospatial processing (visuospatial, V; semantic, S; visuospatial + semantic, V + S). The three groups did not differ in accuracy, but showed different response time profiles. ASP and CTRL participants were fastest on V + S, amenable to both linguistic and nonlinguistic mediation, whereas HFA participants were equally fast on V and V + S, where visuospatial strategies were available, and slowest on S. HFA participants appeared to favor visuospatial over linguistic mediation. The results support the use of linguistic versus visuospatial tasks for characterizing subtypes on the autism spectrum.