Special agents can promote cooperation

Cooperation possesses a very significant role on the development of human being societies and animal colonies. Understanding the emergence of cooperation is a central topic in the study of multi-agent systems. The Prisoner´s Dilemma proposes a question to us, how the emergence of cooperation occurs in the population of selfish agents without centralized control. Previous work mainly focus on the design of dynamics in the specific system, or say the playing rule in game theory. However at some circumstances, it is impossible for the original system to run according to the new rule. This paper incorporates the idea of intervention into the evolution of cooperation at the premise of not changing the playing rule in the original system. With the introduction of a small proportion of special agents, the level of cooperation is increased significantly. In the meantime, this mechanism is robust to the plausible noise existing in the evolution.