The Impact Of Expressing Willingness To Cooperate On The Evolution Of Cooperation In The Space Prisoner’s Dilemma

In the economic society,individuals under the assumption of absolute rationality are selfish.Thus,in the game model,betrayal will dominate the system.But in real life,cooperative behavior is everywhere.This contrast has been discussed by many researchers.Evolutionary game theory has laid a solid foundation for the study of cooperation.In recent years,efforts have been made to seek effective policy updating mechanisms to promote evolution of cooperation in the system.In the context of weak prisoner’s dilemma,this paper introduces the behavior of expressing cooperation intention,and at the same time establishes an effective updating mechanism,and investigates the influence of various factors on cooperation level.In the third chapter,the expression behavior is studied as a character attribute.In a homogeneous finite population,an ordinary differential equation is established.And the expression behavior changes with a certain probability.At the same time,the game subject learns from a neighbor according to Fermi rules.The experimental analysis shows that the more expressing-players,the higher cooperation level.The increase of betrayal temptation b will hinder the evolution of cooperation.The increase of reward-punishment factor re will offset the hindrance effect of the betrayal temptation factor and promote cooperation.In chapter 4,expression behavior is regarded as a behavioral decision,which can be flexibly transformed through learning mechanism.The Monte Carlo simulation is carried out on a two-dimensional grid with spatial structure.The players decide the cooperation probability between themselves and their four neighbors by comprehensively considering the two factors,which involves expression behavior and reputation.The simulation results show that,under the strategy updating mechanism,the proportion of cooperation can be effectively improved by giving moderate trust to the expression behavior and taking the reputation dimension into consideration.Under different parameter values,the influence of betrayal temptation on cooperation is different.In addition,the higher the cost of expression is,the more unfavorable it is to the retention of expression behavior,which is not conducive to the improvement of cooperation level in the system.