The Evolution of Moral Codes of Behavior

Within a standard stochastic evolutionary framework, we study the evolution of morality, both at the level of behavior and at the level of codes of behavior. These moral codes involve sanctioning deviant agents. We provide conditions under which the presence of any small degree of inter-group selection allows the emergence of moral codes which improve social efficiency. The result depends on both the efficacy of the available sanctioning technology and on the ratio of the number of members which societies are composed of to the number of societies in conflict. Group-level mutations (influential leaders, religion and collective deliberative process) can work as an inducement to the evolution of morality. We also consider the possibility that a moral code involves rewards rather than sanctions. Although no system of rewards will evolve, we show that its presence can facilitate the emergence of a sanctioning code