Mechanisms Of Cooperation Evolution On Complex Networks

Cooperation is ubiquitous in nature and human society.Cooperative behavior is embodied in the indestructible family relationship in social animals,the division of labor in human society and the mutual benefit and win-win situation between enterprises.In recent years,the emergence and maintenance of cooperative behavior has become one of the research topics attracting much attention.The researchers found that cooperation which is an altruistic behavior is difficult to emerge and maintain in a group without other mechanisms.At present,researchers have summarized five basic mechanisms to promote cooperation,including kinship selection and direct reciprocity.Besides,the effects of reward.and punishment mechanism,heterogeneity mechanism and migration mechanism on cooperation evolution have also attracted extensive attention from researchers at home and abroad.Evolutionary game theory provides a powerful theoretical framework for the research of cooperative behavior.In the theory,the prisoner's dilemma game model and the snowdrift game model which concern the interaction between two individuals,and the public goods game model which focus the interaction among groups provide theoretical paradigms for the interaction in population and studying the emergence and maintenance of cooperation.In addition,with the rapid development of network science,each part of complex system and its relations are simply abstracted into complex networks.In nature,especially in human society,individuals and their contact relationships can be well represented by network nodes and edges.Therefore,a large number of studies in evolutionary game dynamics have been carried out on complex networks.In this dissertation,based on evolutionary games on complex networks,we have studied the mechanisms of promoting cooperation.The main contents and innovation points of this dissertation are summarized as follows:(1)We introduce the heterogeneous investments induced by historical payoffs into the spatial public goods game where heterogeneous investment is allocated according to the payoffs of individuals in historical steps.Meanwhile,we introduce creatively the individual memory length M and the weight adjustment parameter ? of the influence of different historical steps on the current investment.The results show that the heterogeneous investments induced by historical payoffs can promote the system cooperation significantly,and the smaller M value and ? value are favorable for the spread of cooperation behavior.(2)We propose two directional migration models for pursuit of profitable circumstances.In the cooperator-following migration model,individuals adopt the average migration directions of their cooperative neighbors.In the defector-leaving migration model,individuals move in the opposite directions to their defective neighbors.Within a certain range of parameters,we observe that these two models are favorable for the evolution of cooperation,and it is better for the cooperator-following migration model.And we further investigate the effects of migration speed,interaction radius and population density on the cooperation evolution.(3)We introduce the migration based on historical payoffs into an evolutionary public goods game in two-dimensional space.Meanwhile,a parameter ? is introduced to account for the ambition of individuals.During the evolution,individuals compare their current payoffs with the threshold values determined by the historical payoffs obtained in last round and the parameter ?,and then decide whether to migrate.The results show that there exists an optimal ? which is most favorable to cooperation Furthermore,different population densities and migration speed are introduced to study the cooperation evolution on this system.