Chimpanzees are sensitive to some of the psychological states of others

Animals react and adjust to the behavior of their conspecifics. Much less is known about whether animals also react and adjust to the psychological states of others. Recent evidence suggests that chimpanzees (Pan troglodytes) follow the gaze of others around barriers, past distracters, and check back if they find nothing. Chimpanzees can gauge the motives of a human experimenter and distinguish his intentional from accidental actions. These results suggest that chimpanzees interpret the perceptions and actions of others from a psychological perspective -they seem to know what others can and cannot see and what goals others pursue. It is hypothesized that the co-operation of (1) the ability to operate on psychological states and (2) the motivation to share emotions and experiences with others are key ingredients in the making of human minds.