Alan M. Leslie

Recent studies reveal spontaneous implicit false-belief understanding in infancy. But is this early ability genuine theory-of-mind? Spontaneous tasks may allow early success by eliminating the selection-response bias thought to underlie later failure on standard tasks. However, using anticipatory eye gaze, we find the same bias in non-verbal tasks in both preschoolers and adults. We argue that the bias arises from theory-of-mind competence itself and takes the form of a rational prior to attribute one's own belief to others. Our discussion then draws attention to a number of other inferential hallmarks of early belief-desire reasoning that together suggest it is the real deal.

Kühberger et al. show that producing the Langer effect is considerably more difficult than has been assumed. Although their results clearly demonstrate a need for further exploration of the Langer effect, none of their arguments undermines the evidence against simulation theory that we presented in Nichols et al. (1996). In our study the actor subjects did show an effect, but the prediction subjects did not predict it, despite the fact that they were provided with all the details of the actor's situation. Further, we report additional evidence that corroborates our empirical case against simulation theory.