The Prisoner Dilemma is a typical structure of interaction in human societies. In spite of a long tradition dealing with the matter from different perspectives, the emergence of cooperation or defection still remains a controversial argument from both empirical and theoretical point of views. In this paper an innovative model is presented and analyzed in the attempt to provide a reasonable framing of the issue. A population of boundedly rational agents repeatedly chooses to cooperate or defect. Each agent’s action affects only her interacting mates, according to a network of relationships which is endogenously modifiable since agents are given the possibility to substitute undesired mates with unknown ones. Full cooperation, full defection and coexistence of both cooperation and defection in homogeneous clusters are possible outcomes of the model. A computer program is developed with the purpose of understanding the impact of parameters values on the type of outcome. Numerous simulations are run and the resulting evidence is analyzed and interpreted
