Zoh, Y., Chang, S.W.C. & Crockett, M.J.
Neuropsychopharmacol. (2021).
Abstract
Humans have an exceptional ability to cooperate relative to many other species. We review the neural mechanisms supporting human cooperation, focusing on the prefrontal cortex. One key feature of human social life is the prevalence of cooperative norms that guide social behavior and prescribe punishment for noncompliance. Taking a comparative approach, we consider shared and unique aspects of cooperative behaviors in humans relative to nonhuman primates, as well as divergences in brain structure that might support uniquely human aspects of cooperation. We highlight a medial prefrontal network common to nonhuman primates and humans supporting a foundational process in cooperative decision-making: valuing outcomes for oneself and others. This medial prefrontal network interacts with lateral prefrontal areas that are thought to represent cooperative norms and modulate value representations to guide behavior appropriate to the local social context. Finally, we propose that more recently evolved anterior regions of prefrontal cortex play a role in arbitrating between cooperative norms across social contexts, and suggest how future research might fruitfully examine the neural basis of norm arbitration.
Conclusion
The prefrontal cortex, in particular its more anterior regions, has expanded dramatically over the course of human evolution. In tandem, the scale and scope of human cooperation has dramatically outpaced its counterparts in nonhuman primate species, manifesting as complex systems of moral codes that guide normative behaviors even in the absence of punishment or repeated interactions. Here, we provided a selective review of the neural basis of human cooperation, taking a comparative approach to identify the brain systems and social behaviors that are thought to be unique to humans. Humans and nonhuman primates alike cooperate on the basis of kinship and reciprocity, but humans are unique in their abilities to represent shared goals and self-regulate to comply with and enforce cooperative norms on a broad scale. We highlight three prefrontal networks that contribute to cooperative behavior in humans: a medial prefrontal network, common to humans and nonhuman primates, that values outcomes for self and others; a lateral prefrontal network that guides cooperative goal pursuit by modulating value representations in the context of local norms; and an anterior prefrontal network that we propose serves uniquely human abilities to reflect on one’s own behavior, commit to shared social contracts, and arbitrate between cooperative norms across diverse social contexts. We suggest future avenues for investigating cooperative norm arbitration and how it is implemented in prefrontal networks.
