Evolution of Iterated Prisoner's Dilemma Strategies with Different History Lengths in Static and Cultural Environments

We investigate evolutionary approaches to generate well-performing strategies for the iterated prisoner's dilemma (IPD) with different history lengths in static and cultural environments. The length of the history determines the number of the most recent moves of both players taken into account for the current move decision. The static environment constituting the opponents of the evolved players is made up of ten standard strategies known from the literature. The cultural environment starts with the standard strategies and gradually increases by addition of the best evolved players representing a culture. The performance of the various evolved strategies is compared in specific tournaments. Also, the behavior of an evolved player is analyzed in more detail by looking at the specific game sequences (and corresponding decisions), which out of all possible sequences are actually utilized in a tournament.