Cooperative prisoners and aggressive chickens: evolution of strategies and preferences in 2x2 games

By means of simulations I investigate a two-speed dynamic on strategies and preferences in the prisoners' dilemma and in the chicken game. Players learn strategies according to their preferences while evolution leads to a change in preference composition. With complete information cooperation in the prisoners' dilemma is often achieved, with 'reciprocal' preferences. In the chicken game a symmetric correlated strategy profile is played that is as efficient as the symmetric equilibrium. Among preferences only pure 'hawkish' preferences and 'selfish' preferences survive. With incomplete information, the symmetric equilibrium of the material payoff game is played. All types of preferences are present in the population in the medium run.