Do Chimpanzees (Pan troglodytes) Spontaneously Take Turns in a Reciprocal Cooperation Task?

Reciprocity is considered to be an explanation for altruism toward nonkin. Although there have been many theoretical studies and reciprocity is arguably prevalent in humans, little experimental work has investigated the proximate mechanism of reciprocity in nonhuman animals. The authors tested whether pairs of chimpanzees (Pan troglodytes) would achieve reciprocal cooperation, that is, whether chimpanzees […]