MIGRATION AS A MECHANISM TO PROMOTE COOPERATION

A unified approach is proposed, which integrates game-theoretical models with models of directed motion. Specifically, strategic interactions in space and imitation of more successful neighboring strategies, as studied by spatial games, are combined with success-driven migration based on "test interactions" or wealth-related "neighborhood tagging." It turns out that such directed migration allows cooperators to evade defectors and (in constrast to purely diffusive motion) also to find other cooperators in order to form clusters ("islands of cooperation"). This can increase the cooperation to a great extent. Moreover, success-driven motion leads to interesting spatiotemporal pattern-formation phenomena, which are clearly different from those produced by previously studied spatial games. Despite the simplicity of the model, the forming patterns appear to realistically represent many stylized facts of social interactions, particularly phenomena such as social networking, urban aggregation, social segregation or turn-taking. Furthermore, migration games offer a game-theoretical explanation of social attraction and repulsion, based on payoff-related mobility, and they display a larger variety than conventional games, as their behavior is not invariant to shifting all payoffs by a constant amount. In summary, the combination of strategic interactions and imitation with models of directed motion has high potential for understanding empirical observations in the social, biological and economic sciences from a game-theoretical point of view. Finally, the breakdown of cooperation in the prisoner's dilemma at high values of temptation is explained by configurational analysis.