Abstract

The purpose of the present study was to examine the development of theory-of-mind understanding of preschoolers and to test theory-of-mind hypothesis of autism. The subjects of this study were 10 3-year-olds, 10 4-year-olds, 12 5-year-olds normal children and 10 high-functioning autistic children. Preschoolers and Autistic children were tested on their understanding of false belief by Sally-Anne task and deception by Penny-hiding game. The results of this study are as follows : 1. There were significant group differences on false-belief tese. 3-year-olds were significantly worse than other groups. Autistic children did not differ significantly than 4-year-olds and 5-year-olds. 2. In deception test, we scored the performances by two ways. First, when we scored the hand pattern that children used in guessing and hiding, there were no significant group differences. Second, when we scored the successful object occlusion and information occlusion, 3-year-olds and autistic children were significantly worse than 5-year-olds. 3. In normal and autistic group, the performances of false belief task showed significant correlation with the performances of information occlusion of deception task. These findings support that normal children develop theory-of-mind after 4 years and high-functioning autistic children have theory-of-mind deficit, especially its practical use.