摘要：This article offers the hypothesis that cooperation in the form of generalized reciprocal altruism played an essential role in the bio-social origin of our species. As in other species whose individuals became associated in a permanent way under adverse conditions and as a consequence increased their biological efficacy, in the origin of our mammal, primate and gregarious species, individuals with parental inversion behavior patterns, kinship relation and reciprocal altruism co-selected themselves and increased their biological efficacy at the individual as well at the group level. I also propose that from reiterative cooperative interactions between all the interdependent individuals, a pattern of egalitarian social organization with symmetric structures appeared which resulted efficient as they conjugated individual interests with those of the group and it maintained a dynamic balance with regulation and control mechanisms of those behaviors that could have turned social order unstable.
