Research On Cooperative Dynamics In Mobile Populations

How cooperative behavior can emerge and be maintained in mobile populations has attracted extensive attention from many scholars.Individual migration has been regarded as an important factor for studying this problem.It is worth pointing out that the introduction of individual migration mechanisms can improve effectively the cooperation level in the different social dilemmas.However,it is still unclear how such orientation-driven migration influences the evolution of cooperation and which mode of individual migration can promote the evolution of cooperation more effectively.Hence,this thesis mainly focuses on how the orientation-driven migration mechanism influences the evolution of cooperation in mobile populations.The mainly works and results are as follows:First,we propose an orientation-driven migration mechanism,and try to study how this migration mechanism influences the evolution of cooperation in the spatial public goods game.In our model,individuals can choose the direction of migration depending on the strategy types of their neighbors.The results demonstrate that the introduction of orientation-driven migration mechanism can solve effectively the social dilemma of public goods.In particular,we find that the orientation-driven migration mechanism can strongly enhance the level of cooperation when the speed of individuals is not too high.Interestingly,cooperation can be promoted effectively when individuals are more inclined to evade defectors in their neighbors,whereas cooperation cannot be effectively maintained when individuals are more inclined to move close to cooperators in their neighbors.Compared with random migration,the migration by leaving defectors can promote the evolution of cooperation more effectively.Furthermore,we also find that the level of cooperation can be more enhanced by high strength of repulsive force and low threshold distance of interaction.Then,we propose two motion models depending on orientation-driven migration mechanism to investigate how the average distance between cooperators and defectors in motion dynamics influences the evolution of cooperation.In these two motion models,one is motion model of one cooperator and two defectors;the other is motion model of one defector and two cooperators.The results show that the distance between cooperators and defectors is widened when individuals are principally more inclined toleave defector neighbors and can be reduced when players are motivated to approach cooperator neighbors.Finally,we propose a heterogeneous orientation-driven migration mechanism,and try to study how this migration mechanism influences the evolution of cooperation in the spatial public goods game.In particular,we consider heterogeneous individual migration preferences based on the orientation-driven migration mechanism.The results show that the introduction of heterogeneous orientation-driven migration mechanism can solve effectively the social dilemma of public goods.We show that this mechanism can promote strongly the evolution of cooperation when the mobility of individuals is not too high.Furthermore,we find that cooperation behavior of the populations can emerge easily and be maintained when the average individual migration preferences of the population are more inclined to evade defectors in their neighbors.On the contrary,cooperation cannot be promoted when the average individual migration preferences of the population are more inclined to move close to cooperators in their neighbors.