Towards a better understanding of the evolutionary path of prosocial behaviors

Abstract

Prosocial behaviors have been considered a hallmark of humans in the past. However, accumulating experimental data in comparative cognitive science have revealed that nonhuman animals also show prosocial behaviors. Nevertheless, its evolutionary path has remained unclear despite a great deal of recent research effort. In this paper, I first review experimental studies on prosocial behaviors in nonhuman primates, by focusing on the influences of request behavior and social closeness. Then, I evaluate some factors that have been thought to play an important role in facilitating the convergent evolution of prosocial behaviors (inequity aversion, interdependence, tolerance) based on experimental data. I finally propose some possible future studies to explore the evolutionary path of prosocial behaviors, by referring to the previously discussed psychological mechanism that seems to support nonhuman primates’ prosocial behaviors (Yamamoto & Takimoto, 2012).