IMPACT OF THE HUMAN EGALITARIAN SYNDROME ON DARWINIAN SELECTION MECHANICS

With nothing more than bin selection and reciprocal altruism theories to work with, the selection basis of human degrees of altruism and coo peration is often difficult to explain. However, during our prehistori c foraging phase, a highly stable egalitarian syndrome arose that had profound effects an Darwinian selection mechanics. The band's insisten ce on egalitarianism seriously damped male status rivalry and thereby reduced the intensity of selection within the group by reducing phenot ypic variation at that level, while powerful social pressure to make d ecisions consensual at the band level had a similar effect. Consensual decisions also had another effect: they increased variation between g roups because entire bands enacted their subsistence strategies collec tively and the strategies varied between bands. By reducing the intens ity of individual selection and boosting group effects, these behavior s provided a unique opportunity for altruistic genes to be established and maintained. In addition, the egalitarian custom of socially isola ting or actively punishing lazy or cheating noncooperators reduced the free-rider problem. In combination. these phenotypic effects facilita ted selection of altruistic genes in spite of some limited free riding . This selection scenario remained in place for thousands of generatio ns, and the result was a shift in the balance of power between individ ual and group selection in favor of group effects. This new balance to day is reflected in an ambivalent human nature that exhibits substanti al altruism in addition to selfishness and nepotism.