Abstract

Each generation of evolutionary biologists has brought a fresh wave of attempts to answer the evolutionary riddle of altruism. However, none describe how such a condition could incrementally evolve from a prior condition of non-cooperation. This chapter describes a mechanism that could spontaneously and incrementally give rise to a synergistic codependence among individuals within a social group. It shows that prolonged social living in the absence of reproductive cost can mask selection-maintaining traits important for autonomous living, causing them to drift and degrade to the point where individuals can no longer succeed outside the social context. This ‘social addiction’ will subsequently favour traits that maintain social cohesion because of the high cost of group dispersion. This mechanism contributes a missing complementary component to existing selection-based explanations of the evolution of pro-social and altruistic behaviours.