The Evolution of Social Norms and Individual Preferences

Why does an altruistically inclined player behave altruistically in some contexts and egoistically or spitefully in others? This article provides an economic explanation to this question. The basic argument is centered on the idea that social norms shape our preferences through a process of cultural learning. In particular, we claim that, in contexts with a stable norm of reciprocity, an altruistic player can respond in kind to egoistic or spiteful players by behaving either egoistically or spitefully when confronting them and yet continue to be an altruistic player. This is why, instead of studying the evolution of preferences as such, in this work we analyze the evolution of social norms that indirectly determine individual preferences and behavior. Such a study requires that we distinguish between players' behavioral preferences, or those individuals show with their behavior, and players' intrinsic preferences, or those they inherently support or favor. We argue that, whereas the former can change through the evolution of social norms, in this case a reciprocity norm, the latter are not subject to evolutionary pressures and, therefore, we assume them to be given.