Figure 5.

The success of cooperative strategies on the cycle for shift and death-birth updating, as a function of population size N. On the left is a Prisoner’s Dilemma, on the right is a Snowdrift game. We use the exponential payoff-to-fecundity mapping, π ↦ e^δπ, with selection strength δ = 1. In each case, for sufficiently large N, shift dynamics favor the strategy that maximizes whole-population payoff (while the same is not necessarily true for DB). However, for small population sizes, DB provides a larger benefit to cooperation compared to the shift rule in the examples shown here.