Effect of the migration mechanism based on risk preference on the evolution of cooperation

Individual migration is an effective means of promoting cooperation in the spatial structure. We can think of migration as a kind of risky investment, so risk attitudes can produce an effect on the migration decision. In order to understand the relationship between risk preference and the evolution of cooperation, the spatial prisoner's dilemma game model with individual migration based on risk preference is established. By introducing the homogeneity of risk preference, we find that lower risk aversion values keep a high level of cooperation under a larger defection parameter, while the cooperation level can be raised when the whole population is risk-seeking and at lower risk aversion values under a smaller defection parameter. Under the heterogeneous risk preference assumption, simulation results indicate that the cooperation strategy is a winning strategy in a steady state for a wide parameter space and the cooperation level decreases with increasing in the variance of risk preference. From typical snapshots, we can see that co-evolution of the network structure and cooperation strategy has been realized. Cooperative clusters can also be found in the typical snapshots, which have proved the migration mechanism based on risk to be effective in favoring the evolution of cooperation.