The impact of initial cooperation fraction on the evolutionary fate in a spatial prisoner's dilemma game

Abstract

Although the initial cooperation fraction and its arrangement obviously impacts the equilibrium in spatial prisoner's dilemma (SPD) games, most of the previous studies relying on a simulation approach have by conformity assumed a value of 0.5, thus implying an equal distribution of cooperators and defectors as the established premise. This study first points out that depending on target applications, i.e., biological or general evolutionary dynamical systems, we must select the initial cooperation fraction and its spatial distribution carefully to avoid a misleading conclusion. On the basis of comprehensive numerical experiments and a deductive discussion, wherein both the rule of strategy update and the underlying network are varied, we present a panoramic view of the effects of initial cooperation settings on evolutionary dynamics. Several non-trivial findings are revealed concerning the different impacts of deterministic or stochastic updating, or of homogeneous or heterogeneous underlying topology on evolutionary dynamics.