Evolutionary Bases of Prosociality

Primate societies are, in essence, social contracts: they involve willingness to share resources with others in order to gain longterm advantages in terms of protection against predators. To make this possible, primates have evolved a dual-process bonding mechanism partly dependent on advanced cognitive abilities (the social brain hypothesis) and partly on the use of social grooming to trigger the brain’s endorphin system. Humans have extended both of these so as to allow us to form unusually large and structurally complex social groups. Aside from finding novel behavioural ways of triggering the endorphin system (including laughter, singing, feasting), this has involved coordinating the way the five main social neuropeptides (endorphins, oxytocin, vasopressin, dopamine and serotonin) interact at different social levels.