The effect of assortative mixing on emerging cooperation in an evolutionary network game

A series of numerical experiments using a co-evolutionary model for both networks and strategies for 2 square 2 games was carried out. It was proven that there was an interesting relation between assortative mixing of the evolved network and emerging cooperation. In the prisoner´s dilemma (PD) game class, the evolutionary trail for a weak dilemma game leads to an assortative mixing network, and attains cooperative situation easily. A game implemented with a stronger dilemma, however, makes the network very heterogeneous, featuring a negative assortative coefficient to solve the dilemma situation. This implies that the dilemma strength in PD significantly affects the direction the assortative coefficient takes during evolutionary processes in the co-evolution model.