Playing the Prisoners’ Dilemma with Prisoners

For those of us interested in the science and emotions of human cooperation, a recent study on the Prisoners’ Dilemma (hereafter PD) by Menusch Khadjavi and Andreas Lange of the Department of Economics at the University of Hamburg makes very interesting reading.  Developed by game theorists in the immediate post-war period, and a favorite model of the strategists at the Rand Corporation as they gamed the Cold War strategic nuclear stand-off, the classic payoff structure of the game postulates that the best strategy for a rational player in a single-shot game is always to defect (the classic PD is explained here).

The PD game has been tested in lots of experimental environments using volunteers, but it had never been tested before Khadjavi and Lange’s study on actual prisoners! They sought to control for gendered bias by using a group of female students and comparing their responses to female prisoners.  And following previous studies, they allocated points to the different choices the participants made reflecting the payoff structure of the game.  The female students and prisoners then exchanged these points for Euros in the case of the students and coffee and cigarettes for the prisoners.

Given that the structure of the PD generates defection as the best strategy for a rational egoist, the results of their pioneering study of female prisoners in a German prison were surprising.  They discovered that 55.6 per cent of inmates cooperated instead of seeking the maximum payoff by exploiting their fellow inmates (as against 37 per cent of students who cooperated).  Does this finding have any relevance for the field of International Relations and the challenge of building cooperation between states?  International Relations theorists of a constructivist persuasion have long argued that what is a ‘rational’ move in any game of strategy has to be located in the wider social context within which the game is embedded.  Indeed, Khadjave and Lang explained their finding principally in terms of the prisoners recognising that they would have to continue interacting with their fellows long after the study was over.  In Lange’s words, ‘the feeling that we have is the social structure inside the prison is such that you survive better if you cooperate…Inmates could be more likely to run into fellow participants afterward. Students on a large campus can avoid each other, and their “sentence” usually is a lot shorter.’  Robert Axelrod (building on the work of earlier researchers) showed in his 1984 book, The Evolution of Cooperation that mutual cooperation becomes the best strategy in a PD if the game is (or is expected to be) an iterated one (played over and over again).

But two big questions remain here when it comes to applying the findings of this study to cooperation at the international level.  The first, a variant of which was posed by my former PhD student Erwin Tan in a response he made to the study on Facebook (and which I encourage him to post here), is how many of the prisoners would have played cooperatively had they been dealing not in Euros, but in actual prison sentences?  Such an experiment would clearly – and rightly – not pass any university ethics committee.  However, it would get closer to the central problematique of the PD between states, which is whether to trust the other player when the stakes are very high.  Second, and relatedly, how many governments in an adversarial relationship would make a cooperative first move – even if they believed the other party might reciprocate – if such a conciliatory move entailed accepting high risks to national security?

The findings from Lower Saxony’s women’s prison confirm Axelrod’s earlier findings about the importance of the ‘shadow of the future’, and the wider constructivist claim that identities constitute interests.  But Khadjave and Lang’s study does not address the fundamental question that confronts theorists of security cooperation, namely, how should policy-makers in adversarial relationships act when a cooperative first move could be met with a defection that could lead to a permanent exit from the game for the state initiating cooperation?  In future posts, I will return to this core question, and the contribution that a multidisciplinary approach can make to answering it.

Image source: Flickr / Aapo Haapanen

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