Do Adolescents with High Functioning Autism Verbally Mediate Theory of Mind

Studies suggest that typically developing (TD) individuals verbally mediate theory of mind (ToM). Given that language deficits and ToM deficits are central to autism spectrum disorder (ASD), and given evidence that people with ASD may utilize visuospatial rather than verbal mediation, we sought to examine the role of language inner speech in ToM among adolescents with ASD. We utilized a false belief location-change dual task paradigm to examine whether a simultaneous verbal task, which inhibits inner speech, would differentially interfere with false belief task performance in participants with ASD. We predicted that results would indicate less reliance on inner speech among participants with ASD as compared to TD, and that language skills would be uniquely associated with ToM performance. Contrary to predictions and to the larger ToM literature, we found no group difference in false belief performance, and no additional decrement with verbal load. False belief performance was uniquely associated with VIQ within the ASD group, suggesting a critical role of language in ASD. This finding calls into question the theory that people with ASD "think in pictures" rather than words. Findings were consistent with a proposal that ToM involves both an implicit and an explicit system (Apperly & Butterfill, 2009): because people with ASD struggle with the former, they draw more heavily on an explicit ToM system to compensate for this deficit. Because verbal mediation is necessary for explicit cognitive tasks, such as explicit ToM, people with ASD may, in fact, rely on verbal mediation to “bootstrap” their ToM.