In a typically developing child, ToM develops in a relatively stable and predictable sequence. For example, by 18 months a typical child begins to engage in symbolic play. By 3 years, children begin to understand that there are differences between their own mental states and others, especially with regards to perception. Three-year-olds can differentiate between perceptions, desires and beliefs, which are based on reality and images and dreams, which (according to a three-year-old) are not. Four-year-olds first begin to conceptualize false beliefs and can pass the false belief tests on which much of the ToM research with autism has been based (Yirmiya et al 1998). Common false belief tests include the Sally and Anne test in which the experimenter uses two dolls, "Sally" and "Anne". Sally has a basket and Anne has a box. Experimenters show children a play, where the Sally doll puts a marble in her basket and then leaves. While Sally is away, the Anne doll takes the marble out of Sally's basket and puts it into her box. The children are asked where they think Sally will look for her marble when she returns.
Children are said to "pass" the test if they understand that Sally will most likely look inside her basket before realizing that her marble isn't there. Typical children under the age of four, along with most children with autism (of any age), will answer "Anne's box," apparently unaware that Sally does not know her marble has been moved (Yirmiya et al, 1998). As this test demonstrates, tests of ToM are scored as passing or failing, which seems to indicate that ToM is singular and that one has it or doesn’t. However there is much disagreement in the ToM research over when it actually emerges and to what extent false belief is a global measure of ToM (Tager-Flusberg, 2001). Tager-Flusberg (2001) posits the following as a more developmental perspective of ToM in children with autism, “deficits in theory of mind in autism need to be defined as differences in the rate of developmental change in this domain…more emphasis should be placed on individual differences in the degree of impairment”. Using this as a guideline, one might hypothesize that ToM could be taught to children with autism. Several studies have been published in which participants were taught to pass tests of ToM, however the generalization of those skills to real life social situations was limited (Hadwin, Baron-Cohen, Howlin, & Hill, 1997; Ozonoff & Miller, 1995). For example, Ozonoff and Miller (1995) demonstrated that children with autism with IQs above 70 were able to pass false belief tests after training. However, parent and teacher ratings of social skills indicated no change after intervention. Hadwin et al (1997) measured conversation skills in children with autism after providing training in one of three areas: pretend play, understanding emotions, or understanding belief. They found that participants could be taught belief and emotions, but that play skills did not increase with teaching. In addition, they found that increases in understanding emotions and beliefs 95 The Scandinavian Journal for Human and Applied Sciences , Issue(3), N.(1)