  Carruthers neither endorses nor outright rejects the conclusion that chimpanzees are sentient. His suspicion that even chimpanzees might lack theory of mind, and therefore (on his view) phenomenal consciousness, is based on some ingenious laboratory studies by Povinelli (1996) showing that in interactions with human food providers, chimpanzees apparently fail to understand the role of eyes in providing visual information to the humans, despite their outwardly similar behavior to humans in attending to cues such as facial orientation. The interpretation of Povinelli's work remains controversial. Hare et al. (2000) conducted experiments in which dominant and subordinate animals competed with each other for food, and concluded that “at least in some situations chimpanzees know what conspecifics do and do not see and, furthermore, that they use this knowledge to formulate their behavioral strategies in food competition situations.” They suggest that Povinelli's negative results may be due to the fact that his experiments involve less natural chimp-human interactions. Given the uncertainty, Carruthers is therefore well-advised in the tentative manner in which he puts forward his claims about chimpanzee sentience.