Interaction between games give rise to the evolution of moral norms of cooperation
Fig 9
The behavior of the models under continuous variation of the structure of game B.
The color plot of the density of cooperators, ρC, in the direct interaction model A, and the reputation-based model B, in the SB − TB plane. The top panels show the result of the replicator-mutator dynamics and the bottom panels show the results of simulations in a population of 1000 individuals. In both cases, an unbiased initial condition (random assignment of strategies) is used. I have set R = 3, S = 0, P = 1, T = 5, RB = 3, and PB = 1. The boundaries of bistability are plotted as well. Below this boundary the dynamic is monostable, settling into a fixed point with a low level of cooperation. Above the boundary, a cooperative fixed point becomes stable and the dynamics become bistable. The two branches of the boundary meet at a critical point, where the transition becomes continuous. A comparison shows finite size effects strongly favor cooperation. Here, η = 0.1, and ν = 0.005.