Promotion of cooperation by payoff-driven migration

Migration plays an important role in the evolution of cooperation. Previous studies concerning mobile population often assumed that all agents move with the identical velocity. In this paper, we propose a payoff-driven migration in which the velocity of an agent depends on his/her payoff. A parameter α is introduced to adjust the influence of payoff, when α=0 means that agents all move with the identical velocity while α>0 means that the lower the payoff is, the faster the moving speed is, and vice versa. For the prisoner's dilemma game, we find that in comparison with the case that agents all move with the same speed, cooperation could be promoted strongly when payoff-dependent velocity is considered. Remarkably, the cooperation level is not a monotonic function of α, and there exists an optimal value of α which can lead to the maximum cooperation level. For the snowdrift game, the cooperation level increases with α.