[Perspective] Apes know what others believe
Of all the human uniqueness claims proposed over the years, theory of mind enjoys perhaps the most prominent status. The term “theory of mind” refers to the ability to know what others know, that is, to attribute mental states such as intentions, goals, and knowledge to others. It is widely held to be unique to humans. Yet, given the results reported by Krupenye et al. on page 110 of this issue, this claim is starting to wobble (1). The authors show that apes can correctly anticipate where human actors will look for a hidden item, even if the apes know that the item is no longer there. Ironically, this finding brings us back to square one, because apes played a major role in the formulation of the theory of mind concept. Author: Frans B. M. de Waal