Although theories about the mind are as old as philosophy-and probably older-modern scientific, evolutionary theories of the mind date from only very recently. In 1978, Premack and Woodruff posed the question does the chimpanzee have a theory of mind? However, such a theory of mindparticularly on the part of a chimpanzee-is clearly not something explicit or even something that most people could formulate as a set of propositions if asked to do so and, so, is emphatically not a theory in the same sense in which the general theory of relativity is. The philosopher A. J. Ayer (1910-1989), for example, who has been posthumously diagnosed with an autistic disorder, once remarked that none of his philosophical preoccupations had given him as much trouble as the problem of our knowledge of other minds (Fitzgerald, 2005, p. 141). Indeed, a principal symptom of autism is so-called mind-blindness: deficits in theory of mind that manifest themselves as insensitivity to other people’s feelings; difficulty in interpreting others’ intentions, beliefs, and knowledge; and failure to anticipate the reactions that other people will have to your own behavior. Autistics also typically have difficulty dealing with misunderstandings and are often unable to practice, detect, or understand deception. The result is that their behavior often seems bizarre, callous, or childish to others (Baron-Cohen, 1995; Baron-Cohen & Howlin, 1993).