Explaining the theory of mind deficit in autism spectrum disorder

The theory of mind (ToM) deficit associated with autism has been a central topic in the debate about the modularity of the mind. Most involved in the debate about the explanation of the ToM deficit have failed to notice that autism’s status as a spectrum disorder has implications about which explanation is more plausible. In this paper, I argue that the shift from viewing autism as a unified syndrome to a spectrum disorder increases the plausibility of the explanation of the ToM deficit that appeals to a domain-specific, higher-level ToM module. First, I discuss what it means to consider autism as a spectrum rather than as a unified disorder. Second, I argue for the plausibility of the modular explanation on the basis that autism is better considered as a spectrum disorder. Third, I respond to a potential challenge to my account from Philip Gerrans and Valerie Stone’s recent work (Gerrans, Biol Philos 17:305–321, 2002; Stone and Gerrans, Trends Cogn Sci 10:3–4, 2006a; Soc Neurosci 1:309–319, 2006b; Gerrans and Stone, Br J Philos Sci 59:121–141, 2008)