Endogenous Opioids and Volunteering: On the Evolutionary Significance of Helping Others

The human tendency to help others in need has been subject to trans-, inter-, and multidisciplinary studies (e.g., anthropology, neurobiology, evolutionary psychology, economy), within the frame of studying the mechanisms and adaptive significance of human prosocial behavior. Volunteering directed to unrelated and unfamiliar individuals is one common form of such helping behavior. Helping others may be adaptive for a species at a macro-level, which in turn is mediated by neurobiological mechanisms. A key target for analysis of the neurobiological underpinnings of volunteering is the endogenous opioid system (EOS). This chapter discusses EOS activity as a potential mediator of volunteering behavior. Evidence of the congruence between EOS involvement in social group behavior and social bonding and the role of these phenomena in volunteerism is reviewed. Models and empirical evidence of the mechanisms and adaptive value of helping unrelated others are discussed and integrated, including the mammalian caregiving system, the neurobiological model of prosocial behavior, synchrony promoting social bonding, and stress-driven motivation of prosocial action in immediate needs.