Figure 1. The “wisdom of groups” promotes the evolution of cooperation in the prisoner's dilemma game on the square lattice.

Depicted is the fraction of cooperators ρ_C in dependence on the temptation to defect b, as obtained for different values of α (see figure legend). It can be observed that the larger the value of α the higher the value of b where cooperators are able to dominate and survive the evolutionary competition with defectors.