How evolution affects network reciprocity in Prisoner's Dilemma

Cooperation lies at the foundations of human societies, yet why people cooperate remains a conundrum. The issue, known as network reciprocity, of whether population structure can foster cooperative behavior in social dilemmas has been addressed by many, but theoretical studies have yielded contradictory results so far—as the problem is very sensitive to how players adapt their strategy. However, recent experiments with the prisoner’s dilemma game played on different networks have shown that humans do not consider neighbors’ payoffs when making their decisions, and that the network structure does not influence the final outcome. In this work we carry out an extensive analysis of different evolutionary dynamics for players’ strategies, showing that the absence of network reciprocity is a general feature of those dynamics that do not take neighbors’ payoffs into account. Our results, together with experimental evidence, hint at how to properly model real people’s behavior.