More evidennce on altruism in a structured population

Altruists, Egoists, and Hooligans in a Local Interaction Model Ilan Eshel; Larry Samuelson; Avner Shaked

American Economic Review 1998 88:157-179

We study a population of agents, each of whomcan be an Altruist or an Egoist. Altruism is a strictly dominatedstrategy. Agents choose their actions by imitating others who earn highpayoffs. Interactions between agents are local, so that each agentaffects (and is affected by) only his neighbors. Altruists can survivein such a world if they are grouped together, so that the benefits ofaltruism are enjoyed primarily by other Altruists, who then earnrelatively high payoffs and are imitated. Altruists continue to survivein the presence of mutations that continually introduce Egoists intothe population.