Figure 3
Fixation probability of cooperation shows an optimum at medium connectedness/association sizes with preferential attachment rules. Fixation probability of cooperation with different rules for preferential attachment at different average connectivity. Squares represent random relinking; circles "Get rid of defectors"; and triangles "The friend of my friend is my friend". Filled symbols represent b = ⟨k⟩ and open symbols b = 2⟨k⟩. c = 1, ω 1 = 0.05, ω 2 = 0.95, w = 0.01 and in all cases.