Figure 1
Effect of payoffs on the evolution of homophily and heterophily.
(a) Summary of simulation outcomes for 20 combinations of the payoff ratio a/b (a: payoff to homophilic interaction; b: payoff to heterophilic interaction). Each of the 100 replicate simulations per parameter combination resulted either in the fixation of homophily (blue) or in the fixation of heterophily (yellow). The size of the circles indicates the number of times that the corresponding fixation state was achieved. The brown line indicates the mean frequency of homophilics at the end of the simulation (averaged over all 100 replicates). Homophily only evolved when a was considerably larger than b. (b–d) Representative simulation runs showing the changes in the relative frequency of homophily and heterophily (upper panels) and the associated relative tag frequencies (lower panels). (b) If a/b < 6.5, heterophily spreads to fixation and tag frequencies fluctuate around a uniform distribution. (c) If a/b = 7, either homophily or heterophily spreads to fixation, often after a period of coexistence. (d) If a/b > 7.5, homophily spreads to fixation; only one tag remains in the population. Parameters: N = 1000, M = 10, b = 1, (b) a = 0.1, (c) a = 7, (d) a = 10.
