Figure 4

Evolution of the degree of cooperation of individuals across layers.

Each contour plot shows the evolution of the probability P(x) of finding an individual playing as cooperator in a fraction x of the network layers as b increases. In A m = 15 while for B m = 20. In both cases the networks have N = 250 nodes while each layer is an ER graph with 〈k〉 = 3. Observe that the resilience of cooperation is intrinsically due to the fact that individuals play different strategies across the different layers (no homogeneous strategists appear until defection dominates at very high values of b). For each value of b there is a well defined maximum for P(x).