Coordination of Chimpanzees (Pan troglodytes) in a Stag Hunt Game

Group-living animals frequently face situations in which they must coordinate individual and sometimes conflicting goals. We assessed chimpanzees' ability to coordinate in a Stag Hunt game. Dyads were confronted with a situation in which each individual was already foraging on a low-value food (hare) when a high-value food (stag) appeared that required collaboration for retrieval, with a solo attempt to get the stag resulting in a loss of both options. In one condition visibility between partners was open whereas in the other it was blocked by a barrier. Regardless of condition, dyads almost always (91%) coordinated to choose the higher valued collaborative option. Intentional communication or monitoring of the partner's behavior before decision making-characteristic of much human coordination-were limited. Instead, all dyads adopted a leader-follower strategy in which one partner took the risk of going first, presumably predicting that this would induce the other to join in (sometimes communicating if she was slow to do so). These results show that humans' closest primate relatives do not use complex communication to coordinate but most often use a less cognitively complex strategy that achieves the same end.