Preferential Partner Selection in an Evolutionary Study of Prisoner's Dilemma

This study reports on extensive computer experiments for the "Iterated Prisoner's Dilemma with Choice and Refusal of Partners (IPD/CR)" framework. For example, it is shown that the introduction of choice and refusal tends to enhance the emergence of cooperation in IPD games in comparison to either random or round-robin partner selection. In addition, with choice and refusal of partners, the fitness values of the players tend to cluster fairly tightly into a small number of narrow regions. Within any one fitness region, however, the players consist of genetically diverse players with interaction patterns peculiarly adapted to the choice and refusal mechanism. Detailed sensitivity studies are also reported with respect to key parameters such as the learning algorithm "memory weight," the "minimum tolerance level" below which game offers are refused, and the "refusal payoff" incurred by a player whenever one of his game offers is refused. Annotated pointers to related work can be accessed here: http://www2.econ.iastate.edu/tesfatsi/tnghome.htm