There is an argument regarding whether Japanese children may show a delay in false belief reasoning. The authors investigated whether this apparent delay is genuinely due to the children's difficulty with false belief reasoning, or whether the verbal questioning technique underestimates the competence of the participants. The authors gave 4- and 5-year-old Japanese children a verbal and a nonverbal false belief task. The results revealed that the children performed significantly better in the nonverbal task than in the verbal task. In addition, 5-year-old children performed significantly above chance in the nonverbal task, but not in the verbal task. The results suggested that Japanese children show difficulty with false belief tasks because verbal tasks may underestimate their competence. The results are consistent with the universal view of the development of false belief reasoning.

Key words: theory of mind, false belief task, nonverbal task, preschool children