Evolutionary snowdrift game with disordered environments in mobile societies

Abstract

We investigate an evolutionary snowdrift game on a square N = L × L lattice with periodic boundary conditions, where a population of n0 (n0 ≤ N) players located on the sites of this lattice can either cooperate with or defect from their nearest neighbours. After each generation, every player moves with a certain probability p to one of the player's nearest empty sites. It is shown that, when p = 0, the cooperative behaviour can be enhanced in disordered structures. When p > 0, the effect of mobility on cooperation remarkably depends on the payoff parameter r and the density of individuals ρ (ρ = n0/N). Compared with the results of p = 0, for small r, the persistence of cooperation is enhanced at not too small values of ρ; whereas for large r, the introduction of mobility inhibits the emergence of cooperation at any ρ 0.