Extended Data Fig. 10: Coevolution of strategies and social norms, for all pairs of norms.

Each table cell shows the outcome of the competition among the eight types obtained from pairing one of the four strategies (ALLC, ALLD, DISC_1/2,2 and DISC_2/2,2) with one of the two social norms. The initial proportion of the two social norms is set to 50%. The four different bars in cell represent different probabilities of strategy imitation (w) versus social norm imitation (1−w). Each bar summarizes steady states reached by numerical integration from 975 uniformly distributed different initial strategy frequencies. Hues represent strategies; the brightness of each hue (lighter or darker) indicates the social norm. The rate of cooperation at the equilibria where the population consists entirely of discriminator strategies exceeds 97.5% in all cases. For all panels, the benefit-to-cost ratio is b/c = 5, with error rates of assessment and execution α = 0.02 and ε = 0.02, respectively.