In evolutionary game dynamics in finite populations, selection intensity plays a key role in determining the impact of the game on reproductive success. Weak selection is often employed to obtain analytical results in evolutionary game theory. We investigate the validity of weak selection predictions for stronger intensities of selection. We prove that in general qualitative results obtained under weak selection fail to extend even to moderate selection strengths for games with either more than two strategies or more than two players. In particular, we find that even in pairwise interactions qualitative changes with changing selection intensity arise almost certainly in the case of a large number of strategies.
Wu B, García J, Hauert C, Traulsen A (2013) Extrapolating Weak Selection in Evolutionary Games. PLoS Comput Biol 9(12): e1003381. http://dx.doi.org/10.1371/journal.pcbi.1003381