Figure 1. Evolutionary dynamics of a NPD in adaptive social structure.

We consider a Free Choice World (FCW, see text), grounded on unilateral decision regarding adverse links, such that γ_DD = γ_DC = εγ_CC. a) Gradient of a selection for various values of ε ≥ 1, whereas Z = 200, N = 4, F = 3, β = 1, α = 0.04 and γ_CC = 0.1. Increasing ε effectively transforms the game, at the population level, from a NPD — where cooperation will always tend to decrease — to a different dilemma characterized by two internal fixed points, typical of an N-person coordination game. b) Roots of G(k), as a function of F. Above a certain critical value (F > F_c), two internal roots appear that move to the absorbing states as ε gets larger.