A simulative frame to study the integration of defectors in a cooperative setting.

The paper presents the results of some simulations of the effect of the invasion of non-cooperating subjects into a community adopting a cooperative convention. The convention is described by an indefinitely repeated prisoner-dilemma game. We check the effects on the robustness of the cooperating convention of two characteristics of the game, namely the number of cooperators and the "intelligence" of the players. The relevance for real-world problems is discussed. The simulation program, written in SWARM, is highly flexible, and allows for the consideration of quite a lot of features.