Advanced cognition in wild chimpanzees: lessons from observational studies

Researchers are divided on the extent to which observational studies of the behavior of wild chimpanzees can conclusively identify the cognitive mechanisms underlying social decision-making. Here, we review five well-studied social behaviors exhibited by male chimpanzees — social bonding, reconciliation, cooperative hunting, meat sharing, and coalition formation. For each, we describe the data that can be collected from observational studies and discuss mechanisms that invoke both cognitively simple and advanced cognition. In all of these cases, a range of abilities can result in similar behavioral patterns, demonstrating that purely observational studies alone are insufficient to elucidate the cognitive sophistication of this species. Rather, experiments are necessary to demonstrate the causality of specific cognitive mechanisms. However, observational data are critical to understand the context in which these cognitive capacities are used, and together, these two approaches are necessary for a complete understanding of complex social behavior.