Do chimpanzees know what others see – or only where they look?

A variety of recent studies suggest that apes know what other individuals do and do not see. The results of may be explained by postulating some behavioral rule that individuals have learned that does not involve an understanding of seeing. The patchiness of coverage gives this kind of explanation an ad hoc feeling, especially since there is rarely any concrete evidence that animals actually have had the requisite experiences to learn the behavioral rule – there is just a theoretical possibility. Thus, it is more plausible to hypothesize that apes really do know what others do and do not see.