Chimpanzees do not take advantage of very low cost opportunities to deliver food to unrelated group members

We conducted experiments on two populations of chimpanzees, Pan troglodytes, to determine whether they would take advantage of opportunities to provide food rewards to familiar group members at little cost to themselves. In both of the experiments described here, chimpanzees were able to deliver identical rewards to themselves and to other members of their social […]

The influence of kin relationship and reciprocal context on chimpanzees’ other-regarding preferences

We investigated the evolutionary origin of other-regarding preferences, one of the strong underlying motivations for altruism, in the chimpanzee, Pan troglodytes. Although altruism is expected theoretically to be kin biased and frequent in a reciprocal context, few experimental studies to date have specifically tested these hypotheses from the viewpoint of proximate mechanisms. We examined the […]