Exploitative Behavior in Iterated Prisoners Dilemma
This article explores a study by Yuma Fujimotoa and Kunihiko Kaneko at the University of Tokyo in Japan titled “Emergence of Exploitation as Symmetry Breaking in Iterated Prisoner’s Dilemma”.
The Iterated Prisoners Dilemma is the Prisoners Dilemma but repeated many times. Here, players can not just choose the best outcome based on the current scenario but, also, learn from previous games. So, for example, one player could turn on another in the second round after learning that the first player turned on him in the first. The article explains that previously game theorists believed that exploitation of a player by another would occur only when one player knows the outcome of the previous game and another does not. The study, however, proves otherwise. This study shows that ‘exploitative relationship is possible even when both players know the outcome of previous games. The exploited player receives lower payoff than the other player, but the relationship is still stable because the exploited player accepts the exploitation.
What is interesting about this study is the fact that one player accepts to receive a lower payoff than another rather than fight back and randomize his chances of better payoff. The exploited player trusts the exploiting one to take an option that benefits both. This indicates that humans, in general, would rather cooperate even when it yields lesser payoff. In this case, the exploitative relationship secures the better outcome for both, although, one benefits more than the other.
This study shows how simple game theory ideas can be used to understand how humans evolved to develop relationships and societies with each other. It will be fascinating to see how these ideas are used in the future to understand human interactions and decision making.