The geometrical patterns of cooperation evolution in the spatial prisonerʹs dilemma: An intra-group model

The prisonerʹs dilemma (PD) deals with the behavior conflict between two agents, who can either cooperate (cooperators) or defect. If both agents cooperate (defect), they have a unitary (null) payoff. Otherwise the payoff is T for the defector and null for the cooperator. The temptation T to defect is the only free parameter in the model. Here the agents are represented by the cells of a L×L lattice. The agent behaviors are initially randomly distributed according to an initial proportion of cooperators ρc(0). Each agent has no memory of previous behaviors and plays the PD with his/her eight nearest neighbors. At each generation, the considered agent copies the behavior of those who have secured the highest payoff. Once the PD conflict has been established (1