Trust Game Dynamics And Reputation Mechanism On Social Network

Trust is the lubricant of society and economy and is of vital importance to the development of material and spiritual civilization of human society.It is found almost in all aspects of realistic lives,including institution managing,formation of intimate relationships,interpersonal communication and cooperation,economic behavior and so on.However,trust requires individuals to sacrifice part of potential interests,which will lead to their exposure to a relatively vulnerable condition.Understanding how trust emerges from and evolves in a population consisting of selfish individuals has long been a significant and challenging issue.Evolutionary game theory on complex networks provides a powerful framework for exploring the evolution of trust,where networks stipulate population relationships and games depict interaction rules.Introducing the reasonable social mechanism,an evolutionary game model is established to simulate the individual interaction process in the population.Reputation is generally regarded as a social capital to enhance individual competitiveness.Reputation mechanism is an important method to realize indirect reciprocity.It has been proved by a large number of studies that it could effectively promote the prosocial behavior of structured population.However,trust and reputation have not drawn a considerable concern in the field of EGT.Under this framework,based on the N-player group trust game model with three strategies,this paper mainly investigates how individual reputation mechanisms influence evolutionary dynamics of trust in structured population.The main contents and innovations include the following two points:(1)From the perspective of investors,we study how investors rationally or irrationally trust trustees with dynamic adaptive reputation affect the evolution of trust.The distribution of population reputations satisfies Gaussian distribution in a certain range,and individuals is randomly allocated an initial reputation which will be dynamically adjusted according to each round of individual strategy.The reputation threshold is set in order to assist investors in distinguishing which trustee is more trustworthy and in avoiding interacting with untrustworthy trustees.The degree of rationality is introduced to measure whether investors are rational: if the investor is rational,he/she selectively trusts trustees in consideration of trustees' reputation value;if the investor is irrational,thus he/she trusts every trustee unconditionally.It is found that the degree of rationality of investors determine the level of trust of population on social networks;with a small degree of rationality,reputation threshold could be regarded as the second main factor of the model,promoting the evolution of trust.(2)From the perspective of trustees,we investigate how reputation cultivation and cost of trustees with dynamic adaptive reputation affect the evolution of trust.The trustee can decide whether to spend money cultivating reputation to enhance social competitiveness.Without considering the heterogeneity of individual cost,the Sigmoid function is used to describe the relationship between reputation and cost.It could be found that even if cultivating reputation is expensive,trust will still occur in population;Under appropriate conditions,there is an inverse proportional function relationship between the trustee's willingness to spend and cost,which is found in the trust game for the first time.When one of the parameters of the willingness to spend or the cost is moderate and fixed,there is always an optimal interval for the other parameter making that the trust level or the trustee's global wealth reach the local optimization.