{"id":489,"date":"2012-06-26T11:04:58","date_gmt":"2012-06-26T11:04:58","guid":{"rendered":"http:\/\/rulesofreason.wordpress.com\/?p=489"},"modified":"2012-06-26T11:04:58","modified_gmt":"2012-06-26T11:04:58","slug":"tit-for-tat-no-more-new-insights-into-the-origin-and-evolution-of-cooperation","status":"publish","type":"post","link":"http:\/\/re-design.dimiter.eu\/?p=489","title":{"rendered":"Tit-for-tat no more: new insights into the origin and evolution of cooperation"},"content":{"rendered":"

The Prisoner’s Dilemma <\/a>(PD)\u00a0is\u00a0the<\/em> paradigmatic\u00a0scientific model to understand human cooperation. You would think that after\u00a0several decennia of analyzing this\u00a0deceivingly simple game, nothing new can be learned. Not quite. This<\/a> new paper discovers a whole new class of strategies<\/strong> that provide a unilateral advantage to the players using them in playing the\u00a0repeated version of the game. In effect, using these strategies one can force the opponent to any score one desires. The familiar tit-for-tat<\/a> strategy, which so far\u00a0had been\u00a0assumed to be the optimal way of playing the repeated game, appears to be just the tip of an iceberg of ‘zero determinant’ strategies which ‘enforce a linear relationship between the two players’ scores’<\/a>.<\/p>\n

This is huge and people have already started to\u00a0discuss<\/a> the implications. But what puzzles me is the following: The search for an optimal way to play the repeated PD has been going on at least since the 1980s. The best strategies have been sought analytically, and through simulation (see Robert Axelrod’s\u00a0<\/a>iterated PD tournaments). And yet nobody discovered or stumbled upon ‘zero determinant’ strategies for more than 30 years of dedicated research. So can we expect a rational but not omnipotent actor to use these strategies?<\/strong><\/p>\n

I think the formal answer needs to be ‘yes’ – a rational actor plays the game in the most advantageous way for his\/her interests and if zero determinant strategies provide en edge, then he\/she needs to (and is expected and predicted to) play these. The alternative would be to impose some limitations to the computational capacities of rational actors, but these would always be arbitrary. Where do we draw the line? Is tit-for-tat too complicated or not?\u00a0At the same time, assuming that actors can always find the optimal strategy,\u00a0while consistent with the fundamental assumptions of game theory,\u00a0is unsatisfying for practical reasons.\u00a0If it takes a generation of social scientists 30 years to discover an optimal strategy, how is a single actor supposed to know about it and use it in real-life situations?<\/p>\n

This new class of strategies provides undoubtedly a normatively<\/strong> better way to play the game, but does it have any explanatory<\/strong> or predictive<\/strong> content?<\/p>\n

An alternative route that can lead to actors using\u00a0optimal strategies\u00a0that are too complicated to be analytically discovered by rational but not omnipotent beings is evolution<\/strong>. Actors can experiment with all kinds of strategies,\u00a0some will stumble upon the optimal one, and over time\u00a0natural selection will favor these lucky ones, and by implication their ‘optimal’ strategies. The problem with this reasoning is that what is ‘optimal’ for individuals playing the game is not necessarily optimal for a group of individuals all playing the ‘optimal’ strategy. And if selection acts on groups in addition to individuals these ‘optimal’ strategies might not even survive. In any case, this new paper will certainly make people reconsider not only the origins and mechanisms of cooperation, but the utility and role of game theory in social-scientific explanation as such.<\/p>\n","protected":false},"excerpt":{"rendered":"

The Prisoner’s Dilemma (PD)\u00a0is\u00a0the paradigmatic\u00a0scientific model to understand human cooperation. You would think that after\u00a0several decennia of analyzing this\u00a0deceivingly simple game, nothing new can be learned. Not quite. This new paper discovers a whole new class of strategies that provide a unilateral advantage to the players using them in playing the\u00a0repeated version of the game. In effect, using these strategies one can force the opponent to any score one desires. The familiar tit-for-tat strategy, which so far\u00a0had been\u00a0assumed to be the optimal way of playing the repeated game, appears to be just the tip of an iceberg of ‘zero determinant’ strategies which ‘enforce a linear relationship between the two players’ scores’. This is huge and people have already started to\u00a0discuss the implications. But what puzzles me is the following: The search for an optimal way to play the repeated PD has been going on at least since the 1980s. The best strategies have been sought analytically, and through simulation (see Robert Axelrod’s\u00a0iterated PD tournaments). And yet nobody discovered or stumbled upon ‘zero determinant’ strategies for more than 30 years of dedicated research. So can we expect a rational but not omnipotent actor to use these strategies? I think the formal answer needs to be ‘yes’ – a rational actor plays the game in the most advantageous way for his\/her interests and if zero determinant strategies provide en edge, then he\/she needs to (and is expected and predicted to) play these. The alternative would be to impose some limitations to the…<\/p>\n

Continue readingTit-for-tat no more: new insights into the origin and evolution of cooperation<\/span><\/a><\/div>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"spay_email":"","jetpack_publicize_message":"","jetpack_is_tweetstorm":false},"categories":[18],"tags":[150,151,220,252,254,278,288,353,456,522,559,572,648,694,699],"jetpack_featured_media_url":"","jetpack_publicize_connections":[],"jetpack_sharing_enabled":true,"jetpack_shortlink":"https:\/\/wp.me\/p7g3hj-7T","jetpack-related-posts":[{"id":372,"url":"http:\/\/re-design.dimiter.eu\/?p=372","url_meta":{"origin":489,"position":0},"title":"Torture and game theory","date":"March 15, 2012","format":false,"excerpt":"The latest issue of Political Research Quarterly has an interesting and important exchange about the use of game theory to understand the effectiveness of torture\u00a0for eliciting truthful information. In this post I summarize the discussion, which is quite instructive for illustrating the prejudices and misunderstandings people have about the role\u2026","rel":"","context":"In "Game theory"","img":{"alt_text":"","src":"","width":0,"height":0},"classes":[]},{"id":934,"url":"http:\/\/re-design.dimiter.eu\/?p=934","url_meta":{"origin":489,"position":1},"title":"The Discursive Dilemma and Research Project Evaluation","date":"November 21, 2017","format":false,"excerpt":"tl; dr When we collectively evaluate research proposals,\u00a0we can reach the opposite verdict\u00a0depending on how we aggregate the individual evaluations, and that's a problem, and nobody seems to care or provide guidance how to proceed. Imagine that three judges need to reach a verdict together using majority rule. To do\u2026","rel":"","context":"In "Normative political theory"","img":{"alt_text":"","src":"","width":0,"height":0},"classes":[]},{"id":151,"url":"http:\/\/re-design.dimiter.eu\/?p=151","url_meta":{"origin":489,"position":2},"title":"Game theory and real estate negotiations","date":"November 14, 2011","format":false,"excerpt":"Here is a puzzle: You meet a real estate agent for a property you are interested in. The\u00a0house has an asking prize\u00a0and you haven't made\u00a0any offers yet. The realtor mentions casually that she has just had an offer for\u00a0the house which she has rejected. Would you ask what the offer\u2026","rel":"","context":"In "Game theory"","img":{"alt_text":"","src":"","width":0,"height":0},"classes":[]},{"id":243,"url":"http:\/\/re-design.dimiter.eu\/?p=243","url_meta":{"origin":489,"position":3},"title":"Myron's Law","date":"January 23, 2012","format":false,"excerpt":"\"Asymptotically, any finite tax code collects zero revenue\" This is what economist Paul Romer calls Myron's Law (after Myron Scholes). It is a great aphorism as it illuminates a neglected source of institutional change - the opportunistic adaptation of the regulated actors to the rules which spurs transformations of the\u2026","rel":"","context":"In "Institutions and regulation"","img":{"alt_text":"","src":"","width":0,"height":0},"classes":[]},{"id":415,"url":"http:\/\/re-design.dimiter.eu\/?p=415","url_meta":{"origin":489,"position":4},"title":"Debt and the nature of money","date":"April 3, 2012","format":false,"excerpt":"When I wrote that David Graeber's book opens your eyes, that was not just a figure of speech. First, consider this: In recent weeks, Theodoros Mavridis has bought fresh eggs, tsipourou (the local brandy: beware), fruit, olives, olive oil, jam, and soap. He has also had some legal advice, and\u2026","rel":"","context":"In "economic policy"","img":{"alt_text":"","src":"https:\/\/i2.wp.com\/re-design.dimiter.eu\/wp-content\/uploads\/2012\/04\/money-1.jpg?resize=350%2C200","width":350,"height":200},"classes":[]},{"id":233,"url":"http:\/\/re-design.dimiter.eu\/?p=233","url_meta":{"origin":489,"position":5},"title":"Spatial theory and Scottish Independence","date":"January 17, 2012","format":false,"excerpt":"The plans for a referendum on Scottish independence offer a nice opportunity for applying spatial analysis. The latest point of contestation is whether a third option (enhanced devolution) should be offered to the voters in addition to the 'Yes' and 'No'. The UK government is against including the third option,\u2026","rel":"","context":"In "Game theory"","img":{"alt_text":"","src":"","width":0,"height":0},"classes":[]}],"_links":{"self":[{"href":"http:\/\/re-design.dimiter.eu\/index.php?rest_route=\/wp\/v2\/posts\/489"}],"collection":[{"href":"http:\/\/re-design.dimiter.eu\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/re-design.dimiter.eu\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/re-design.dimiter.eu\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/re-design.dimiter.eu\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=489"}],"version-history":[{"count":0,"href":"http:\/\/re-design.dimiter.eu\/index.php?rest_route=\/wp\/v2\/posts\/489\/revisions"}],"wp:attachment":[{"href":"http:\/\/re-design.dimiter.eu\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=489"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/re-design.dimiter.eu\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=489"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/re-design.dimiter.eu\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=489"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}