Analyzing Axelrod's Prisoner’s Dilemma Tournaments

Nicole Christian

Evolutionary Psychology

Dr. Corby

July 25th, 2015

Final

Robert Axelrod organized two computer tournaments based on the Prisoner’s dilemma. Why did he do this? What were the results of the tournaments? What were the factors that made the computer programs successful or not? How is this relevant to evolutionary psychology?

Prisoners dilemma, is a theoretical game played between two individuals who can choose to either cooperate with one another or defect. Either choices give completely different payoffs. Both individuals cooperating, gives a greater pay off allowing for both individuals to benefit whereas one individual defecting while the other cooperates allows for one individual (defecting individual) to receive

In the completion of this computer tournament, Tit for Tat achieved the highest score against all other strategies and was proven to be the better strategy in the prisoners dilemma. According to Axelrod, there were four properties that will make a strategy successful. The first being the ability to cooperate as long as the opponent was willing to cooperate and this is turn would avoid unnecessary conflicts. The second being provocation by defecting once the other opponent has defected. Thirdly, forgiveness, whereas the player was able to revert back to cooperation after being provoking to their opponent. Lastly, allowing for the players strategies to be clearly understood to allow for the other player to recognize their plans and course of action as to adapt to this pattern. Other factors making Tit for Tat so successful was it was robust, thus having strength to beat all strategies that it came up against. Tit for Tat also had stability whereas it could not be invaded by any other strategies. Also Tit for Tat was viable in that it worked successfully amongst all other strategies. All other program strategies that did not possess these properties were unsuccessful. This is relevant to evolutionary psychology because it shows some strategies are evolutionarily stable, whereas others are not. Evolutionary Stable Strategies (ESS) meaning if a strategy is adopted by a population in a particular environment, this strategy

Genes transfer biological traits which are transferred from parent to offspring and typically confer some benefit to its holder. It may not be optimal benefit, however does confer some benefit. Memes on the other hand transfer psychologically appealing information. Genes typically need a generation or so to be transmitted whereas memes spread quicker than would genes and can be transmitted in a matter of seconds. While there are some substantial differences the two are also very similar. Both memes and genes are very good at getting themselves copied. These genes that are good at copying themselves will become more prevalent in the environment and comparably so will those memes that are most psychologically appareling. A meme, according to Dawkins, can be considered a cultural counterpart to a gene. For example, although we don’t know the specific origins of where God came from, the idea of a divine being can often be seen in writings, art and music and even word of mouth. These tools have essentially been responsible for carrying on this idea of a divine being, thus making this a