The Evolution of Cooperation: Some Notes on the Importance of Discrimination

Abstract

Hovi, J. The Evolution of Cooperation: Some Notes on the Importance of Dis crimination. Cooperation and Conflict, XXIV, 1989, 55-68.

This paper compares the prospects for cooperation in compound Prisoner's Dilemma supergames under two different regimes — one where discriminating behaviour is allowed, and one where it is effectively banned. Three "stages" in the evolutionary process are being discussed. First, the author considers the conditions under which a process towards cooperation can be initiated. It is found that these conditions tend to be more strict when discrimination is banned than when it is allowed. Second, the prospects for expansion of cooperative strategies, once established, are investigated. It is concluded that when discrimination is effectively banned, a group of cooperators cannot expect others to join in on a voluntary basis. This is a very different situation from the one existing under a regime where discrimination is allowed. Finally, the paper considers the possible stability properties under each regime, of a situation characterized by universal cooperation. It is indicated that although a ban on dis crimination does not inhibit stability, it might at least make it more fragile.