Evolution of spite versus evolution of altruism through a disbandment mechanism

Abstract

Altruism and spite are costly to the actor; therefore, from the perspective of natural selection, the existence of them is a mysterious phenomenon and require explanation. If altruistic individuals are more likely to be recipients for altruism than non-altruistic individuals, then altruism can be favored by natural selection. Similarly, if spiteful individuals are less likely to be recipients for spite than non-spiteful individuals, then spite can be favored by natural selection. Spite is altruisms evil twin or ugly sister of altruism. In some mechanisms (e.g. repeated interaction), if altruism is favored by natural selection, then spite is also favored by natural selection. In contrast, there is a situation which facilitates the evolution of altruism but is unlikely to facilitate the evolution of spite. Population structure is one typical example. Here we focus on the mechanism in which individuals choose to keep the interaction or stop the interaction according to the opponents behavior. We, by using evolutionary game theory, investigate the evolution of altruism and the evolution of spite under this mechanism. Our model shows that the evolution of spite is less likely than the evolution of altruism. This main result provides a nice intuition for why altruism is more abundant than spite in general in the real world.