Survival of cooperation without and with wealth accumulation.
Figures are generally photos, graphs and static images that would be represented in traditional pdf publications.
The contour plot shows the percentage of runs in which at least 1% of cooperators survive after 1000 steps, as a function of the payoff parameters (horizontal axis) and (vertical axis). Note that cooperation can survive in much more hostile conditions ( and ) when payoffs are unequal (panel B) than when they are not (panel A). In particular, for extreme values ( close to 2 and close to −1), cooperation never survives without wealth accumulation, but can survive with it.