Cooperation in Social Networks of Trust

This paper proposes a model based on both direct reciprocity and the use of social network structures to incentive cooperation in human societies. The absence of third-party reputation assures that very few opportunities are left for lying and misreporting of information by the members of the community. Social relationships are built according to the criterion that nodes seek to interact with others at least as cooperative as themselves. This idea together with the effect of nodes prioritizing with their relationships produces the highest benefits for the most cooperative behaviours while the performance of uncooperative nodes is heavily penalized. The trust model is applied to a number of simulations of the iterated Prisoner´s dilemma game.