Uncertainty of cooperation in random scale-free networks

We Study the spatial prisoner's dilemma game where the players are located oil the nodes of a random scale-free network. The prisoner's dilemma game is a powerful too] and has been used for the study of mutual trust and cooperation among individuals in structured populations. We vary the structure of the network and the payoff values for the game, and show that the specific conditions can greatly influence the outcome of the game. A variety of behaviors are reproduced and the percentage of cooperating agents fluctuates significantly, even in the absence of irrational behavior. For example, the steady state of the game may be a configuration where either cooperators or defectors dominate, while in many cases the solution fluctuates between these two limiting behaviors. (C) 2009 Elsevier B.V. All rights reserved.