Figure 4
The strength of extortion has a negligible impact on the stationary frequencies of competing strategies and it does not affect the evolutionary stability of extortion and cooperation.
Depicted are the stationary frequencies of surviving strategies in dependence on the strength of extortion χ, as obtained for the social dilemma strength b = 2 on a square lattice. It can be observed that the variations of all frequencies are small. Expectedly, larger values of χ favor extortion. The neutral drift of TFT players therefore becomes slightly less prolific, which in turn also slightly decreases the frequency of cooperators. Interestingly, the stationary frequencies of strategies at b = 2 and their χ-dependency are practically indistinguishable for the square lattice and the random regular graph. This further highlights the irrelevance of the structure of the interaction network under myopic best response updating and thus also the universality of the presented results.
