Small-scale deceit: deception as a marker of two-, three-, and four-year-olds' early theories of mind.

This research report summarizes the results of a study into the abilities of 2-, 3-, and 4-year-old children to deceptively lead others into false beliefs, and is intended to help arbitrate a growing controversy as to when young persons first acquire some theory-like understanding of other minds. Utilizing a novel hide-and-seek board game as a context within which to observe children's spontaneous use of deceptive strategies, a total of 50 subjects between the ages of 2 1/2 and 5 were tested. In contrast to the competing findings of others, which are claimed to establish that children younger than approximately 4 suffer a cognitive deficit that wholly blocks them from the possibility of entertaining any sort of contrastive beliefs about beliefs, the results of this study show that even 2 1/2-year-olds are capable of already successfully employing a range of deceptive strategies that both trade upon an awareness of the possibility of false beliefs and presuppose some already operative theory of mind.