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The Evolution of Cooperation
The Evolution of Cooperation provides valuable insights into the age-old question of whether unforced cooperation is ever possible. Widely praised and much-discussed, this classic book explores how cooperation can emerge in a world of self-seeking egoists—whether superpowers, businesses, or individuals—when there is no central authority to police their actions. The problem of cooperation is central to many different fields. Robert Axelrod recounts the famous computer tournaments in which the “cooperative” program Tit for Tat recorded its stunning victories, explains its application to a broad spectrum of subjects, and suggests how readers can both apply cooperative principles to their own lives and teach cooperative principles to others.
264 pages, Paperback
First published April 15, 1984
About the author
Robert Axelrod
13 books107 followersFrom wikipedia:
Robert Axelrod (born 1943) is a Professor of Political Science and Public Policy at the University of Michigan. He has appointments in the Department of Political Science and the Gerald R. Ford School of Public Policy. Prior to moving to Michigan, he taught at the University of California, Berkeley (1968-1974). He holds a BA in mathematics from the University of Chicago (1964) and a PhD in political science from Yale University (1969).
He is best known for his interdisciplinary work on the evolution of cooperation, which has been cited in numerous articles. His current research interests include complexity theory (especially agent-based modeling), and international security. Among his honors and awards are membership in the National Academy of Sciences, a five-year MacArthur Prize Fellowship, the Newcomb Cleveland Prize of the American Association for the Advancement of Sciences for an outstanding contribution to science, and the National Academy of Sciences Award for "Behavioral Research Relevant to the Prevention of Nuclear War".
Recently Axelrod has consulted and lectured on promoting cooperation and harnessing complexity for the United Nations, the World Bank, the U.S. Department of Defense, and various organizations serving health care professionals, business leaders, and K-12 educators.
Axelrod was the President of the American Political Science Association (APSA) for the 2006-2007 term. He focused his term on the theme of interdisciplinarity.
In May 2006, Axelrod was awarded an honorary degree by Georgetown University.
Robert Axelrod (born 1943) is a Professor of Political Science and Public Policy at the University of Michigan. He has appointments in the Department of Political Science and the Gerald R. Ford School of Public Policy. Prior to moving to Michigan, he taught at the University of California, Berkeley (1968-1974). He holds a BA in mathematics from the University of Chicago (1964) and a PhD in political science from Yale University (1969).
He is best known for his interdisciplinary work on the evolution of cooperation, which has been cited in numerous articles. His current research interests include complexity theory (especially agent-based modeling), and international security. Among his honors and awards are membership in the National Academy of Sciences, a five-year MacArthur Prize Fellowship, the Newcomb Cleveland Prize of the American Association for the Advancement of Sciences for an outstanding contribution to science, and the National Academy of Sciences Award for "Behavioral Research Relevant to the Prevention of Nuclear War".
Recently Axelrod has consulted and lectured on promoting cooperation and harnessing complexity for the United Nations, the World Bank, the U.S. Department of Defense, and various organizations serving health care professionals, business leaders, and K-12 educators.
Axelrod was the President of the American Political Science Association (APSA) for the 2006-2007 term. He focused his term on the theme of interdisciplinarity.
In May 2006, Axelrod was awarded an honorary degree by Georgetown University.
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October 27, 2017
Remember that iconic scene in Wonder Woman, where she crosses No Man’s Land amidst enemy bullets and inflicts damage at the other side. Well, she was ruining a relatively peaceful ecosystem built on mutual restraint over mutual punishment. World War I, on a national level, was a zero sum game where loss on one side meant gain on the other. But on local levels, specifically along the Western Front, between France and Germany, a curious system of ‘live and let live’ emerged. Trench Warfare, limited within narrow trenches few hundred yards apart, with all its disgusting horrors became the stage for something amazing in history- a classic example of reciprocal altruism in a world of unconditional defection. A feeling of solidarity developed among enemy soldiers over time, and it was characterized by ad hoc weather truces, common lunch times and even combined Christmas celebration. During Christmas Germans put up decorated table top trees over the trenches, and British-French soldiers responded by singing Carol songs. They left their weapons in trenches and came up to shake hands in no man’s land; swapped presents, traded stuff, buried the dead, shared barrels of beers and cigars till the whole morning. In some portions along this hundreds of miles stretch, the period of goodwill lasted as long as a whole week. This restraint was not due to weakness, but rather the rationale of defection being self-defeating; much like modern day deterrence between Nuclear States over fear of mutually assured destruction.
In this seminal work, Robert Axelrod, with unusual clarity discredits friendship or kinship as the essential necessities for cooperation based on reciprocity, even in inception stage. And argues that, under suitable characteristics, cooperative relationships can well arise even between antagonists. According to Hobbes, and other earlier political theorists like Rousseau and Locke, human beings are primordially selfish individuals, who competed among each other for their own solitary, brutal and short life. Strong central authority (Leviathan) later entered into society by rationality of mutual interaction and hence, however unnatural of basic human nature, is required for maintaining cooperation among individuals. One can argue against this with evolutionary and biological examples that show social cooperation being hardwired into living consciousness. What Axelrod did was to arrange a computer tournament for an iterated Prisoner’s Dilemma problem and invite computer program strategies from his friends and colleagues.
Prisoner’s Dilemma is a thought experiment, a set of circumstances that forms the building block of Game Theory. In a Minority Report scenario, two potential prisoners are captured and interrogated separately for conviction. Each of them can stab the other in their back for lesser sentence or cooperatively deny for a favourable outcome of walkaway. The possible scenarios in ascending order of pay offs are as follows- unilateral defection from partner, mutual defection, mutual cooperation and unilateral restraint from partner. Since individuals cannot control the other person’s behaviour, each player is in a dilemma whether to rat out ones partner for maximum pay off or to cooperate for the mutually preferable outcome. Game theory expands this to behavioural problem with mathematical formalities and tries to optimize strategies for negotiations in economics, diplomacy, biology, psychology etc. In Axelrod’s tournament, various computer programs competed against each other for over 200 times in this non zero sum setting.
In all the possible interactions one strategy came out dominant pushing every other programs into extinction and its relative success had nothing to do with its author or brevity or length. This simple strategy known, rather appropriately, as TIT for TAT, was just two lines of code.
First line - be nice.
Second line - do what the other player just did.
So T4T starts off cooperating with the opponent and continue doing that till the other player defects. It will then defect and again switch back to cooperation once the opponent starts to cooperate. Though mathematically the optimum option is to defect in all moves, the nicer strategies was found to be outweighing the meaner ones in competition, with TIT for TAT dominating them all. It was a very robust program- nice to begin with, retaliatory when required, and was forgiving and clear; but not free of failures. A signal glitch or mistake in translation might cause a string of recriminations and counter recriminations between players employing T4T. So, it would be extremely important to reduce the echo effects while employing the strategy for high stake environments, as defection strings can cause escalations as far-fetched as Cuban Missile Crisis. A forgiving TIT for TAT was found to be effective, though not immune of exploitation, in such conditions, where it switches to a forgiving strategy after certain rounds of mutual defection. Axelrod argues that the maximization of outcome depends on characteristics of a particular strategy, nature of other strategies with which it most interacts and the history of interactions.
Coming back to the Trench Warfare, No Man’s Land basically represented a dynamic equilibrium of stalemate. The troops at both sides were large enough for accountability and small enough for controlling individual behaviour. Since not every bullet, grenade or shell fired in earnestness would hit the exact target, there was an inherent tendency towards descalation. Demonstration of retaliatory capacities and verbal arguements were internally suppressed by superiors, and during the rotation of troops, outgoing soldiers made it their business to familiarize the new recruits with the status quo. Infantries often offered delicacies for Artilleries as gentle incentives for not provoking the enemy side, since they were relatively safe with fewer stakes in this ‘live and let live’ system than them. And on a macroscopic scale, especially after the joint Christmas celebration, High Command of German, French and Britain wanted an end to these tacit truces as a pacified system will only sap morale from war’s ceaseless policy of offense.
Though I might come out as a heretic in this comparison, war time General’s behaviour can be observed in Wonder Woman too whose primary objective was killing Aries. The immediate and extended payoffs for both Aries and Diana were big enough to justify their actions. Though offensive demonstrations and firings can be heard in background, there was no direct enemy attack towards the trenches, even in the movie depiction. And it was her crossing of No Man’s Land that destroyed the truce and escalated the war on both fronts, killing the microscopic payoffs for macroscopic ones. Also, it would be worthwhile to note that the attack was instigated by outsiders (Trevor and Team) than the soldiers involved in the counterbalance, who might have been in the moral enigma of breaking their side of trust. Similarly in further history of actual WWI, High Command imposed raids and retaliatory efforts eventually collapsed the Trench Warfare system. Even during those orders for mandatory offense, ethics of cooperation was maintained keeping the per-functionary and routine firing aggressive enough to satisfy high command and contained enough to avoid any retaliation, as long as they could.
Axelrod extended his computer simulation strategies into an evolutionary scenario, where winning program gets to create copies of themselves, and running them for many generations. Even in a horribly hostile world, if the nice programs had enough chance to interact, it was found that they can eventually take over the world full of meaner strategies.
The beauty of altruistic behaviour in negative spaces can be observed in evolutionary biology as well. Though rational agents always defect in Prisoner’s Dilemma, knowledge about options of other party drastically changes the scene. When third parties are watching, the stakes of current situation expands from those immediately at hand to the reputation and future interactions of players. Internet bullying under the mask of anonymity and friendliness a regular customer might enjoy in a shop can be considered as crude examples. Anyway it gets even more complicated with changing pay offs and concentrating interactions. I was constantly drawn towards Cixin Liu’s Dark Forest deterrence theory and its aftermath in later installments of Three Body Problem, as my very own literary example for applying the half cooked nuances of game theory and prisoner’s dilemma.
Real world problems are far more complex than Axelrod’s computer simulation, with multiple players and complex pay offs that demands sophistication in analysis. But this propensity for reciprocal altruism among antagonists was a theory robust and well-articulated enough to have my undivided attention. And this karma based upright, forgiving and yet retaliatory strategy is a nice take away for life, maybe with more leaning towards reconciliation.
In this seminal work, Robert Axelrod, with unusual clarity discredits friendship or kinship as the essential necessities for cooperation based on reciprocity, even in inception stage. And argues that, under suitable characteristics, cooperative relationships can well arise even between antagonists. According to Hobbes, and other earlier political theorists like Rousseau and Locke, human beings are primordially selfish individuals, who competed among each other for their own solitary, brutal and short life. Strong central authority (Leviathan) later entered into society by rationality of mutual interaction and hence, however unnatural of basic human nature, is required for maintaining cooperation among individuals. One can argue against this with evolutionary and biological examples that show social cooperation being hardwired into living consciousness. What Axelrod did was to arrange a computer tournament for an iterated Prisoner’s Dilemma problem and invite computer program strategies from his friends and colleagues.
Prisoner’s Dilemma is a thought experiment, a set of circumstances that forms the building block of Game Theory. In a Minority Report scenario, two potential prisoners are captured and interrogated separately for conviction. Each of them can stab the other in their back for lesser sentence or cooperatively deny for a favourable outcome of walkaway. The possible scenarios in ascending order of pay offs are as follows- unilateral defection from partner, mutual defection, mutual cooperation and unilateral restraint from partner. Since individuals cannot control the other person’s behaviour, each player is in a dilemma whether to rat out ones partner for maximum pay off or to cooperate for the mutually preferable outcome. Game theory expands this to behavioural problem with mathematical formalities and tries to optimize strategies for negotiations in economics, diplomacy, biology, psychology etc. In Axelrod’s tournament, various computer programs competed against each other for over 200 times in this non zero sum setting.
In all the possible interactions one strategy came out dominant pushing every other programs into extinction and its relative success had nothing to do with its author or brevity or length. This simple strategy known, rather appropriately, as TIT for TAT, was just two lines of code.
First line - be nice.
Second line - do what the other player just did.
So T4T starts off cooperating with the opponent and continue doing that till the other player defects. It will then defect and again switch back to cooperation once the opponent starts to cooperate. Though mathematically the optimum option is to defect in all moves, the nicer strategies was found to be outweighing the meaner ones in competition, with TIT for TAT dominating them all. It was a very robust program- nice to begin with, retaliatory when required, and was forgiving and clear; but not free of failures. A signal glitch or mistake in translation might cause a string of recriminations and counter recriminations between players employing T4T. So, it would be extremely important to reduce the echo effects while employing the strategy for high stake environments, as defection strings can cause escalations as far-fetched as Cuban Missile Crisis. A forgiving TIT for TAT was found to be effective, though not immune of exploitation, in such conditions, where it switches to a forgiving strategy after certain rounds of mutual defection. Axelrod argues that the maximization of outcome depends on characteristics of a particular strategy, nature of other strategies with which it most interacts and the history of interactions.
Coming back to the Trench Warfare, No Man’s Land basically represented a dynamic equilibrium of stalemate. The troops at both sides were large enough for accountability and small enough for controlling individual behaviour. Since not every bullet, grenade or shell fired in earnestness would hit the exact target, there was an inherent tendency towards descalation. Demonstration of retaliatory capacities and verbal arguements were internally suppressed by superiors, and during the rotation of troops, outgoing soldiers made it their business to familiarize the new recruits with the status quo. Infantries often offered delicacies for Artilleries as gentle incentives for not provoking the enemy side, since they were relatively safe with fewer stakes in this ‘live and let live’ system than them. And on a macroscopic scale, especially after the joint Christmas celebration, High Command of German, French and Britain wanted an end to these tacit truces as a pacified system will only sap morale from war’s ceaseless policy of offense.
Though I might come out as a heretic in this comparison, war time General’s behaviour can be observed in Wonder Woman too whose primary objective was killing Aries. The immediate and extended payoffs for both Aries and Diana were big enough to justify their actions. Though offensive demonstrations and firings can be heard in background, there was no direct enemy attack towards the trenches, even in the movie depiction. And it was her crossing of No Man’s Land that destroyed the truce and escalated the war on both fronts, killing the microscopic payoffs for macroscopic ones. Also, it would be worthwhile to note that the attack was instigated by outsiders (Trevor and Team) than the soldiers involved in the counterbalance, who might have been in the moral enigma of breaking their side of trust. Similarly in further history of actual WWI, High Command imposed raids and retaliatory efforts eventually collapsed the Trench Warfare system. Even during those orders for mandatory offense, ethics of cooperation was maintained keeping the per-functionary and routine firing aggressive enough to satisfy high command and contained enough to avoid any retaliation, as long as they could.
Axelrod extended his computer simulation strategies into an evolutionary scenario, where winning program gets to create copies of themselves, and running them for many generations. Even in a horribly hostile world, if the nice programs had enough chance to interact, it was found that they can eventually take over the world full of meaner strategies.
The beauty of altruistic behaviour in negative spaces can be observed in evolutionary biology as well. Though rational agents always defect in Prisoner’s Dilemma, knowledge about options of other party drastically changes the scene. When third parties are watching, the stakes of current situation expands from those immediately at hand to the reputation and future interactions of players. Internet bullying under the mask of anonymity and friendliness a regular customer might enjoy in a shop can be considered as crude examples. Anyway it gets even more complicated with changing pay offs and concentrating interactions. I was constantly drawn towards Cixin Liu’s Dark Forest deterrence theory and its aftermath in later installments of Three Body Problem, as my very own literary example for applying the half cooked nuances of game theory and prisoner’s dilemma.
Real world problems are far more complex than Axelrod’s computer simulation, with multiple players and complex pay offs that demands sophistication in analysis. But this propensity for reciprocal altruism among antagonists was a theory robust and well-articulated enough to have my undivided attention. And this karma based upright, forgiving and yet retaliatory strategy is a nice take away for life, maybe with more leaning towards reconciliation.
September 19, 2014
It’s not overstating the case to say that Robert Axelrod’s The Evolution of Cooperation is literally the most important book of the last 100 years and will change the course of human history.
Um, Andy, I think you need to revisit the definitions of certain words, like “literally” and “overstating.”
OK, granted. But the implications of the game theory research and analysis presented here are so profoundly important, it’s difficult not to descend into hyperbole. Or ascend, as the case may be. Sure, at first glance it appears to be an account of legions of math and computer nerds trying to beat one another at a silly game. Who would suspect that these nerds may have essentially discovered the philosophical glue that holds all of society together? And done so with programs written in just a handful of code lines written in BASIC and FORTRAN, no less?
I did, but I cheated, of course. I was already convinced of game theory’s profound significance before I ever picked this up. I was doing research, reading everything I could find on the subject for my own book about game theory, my premise being that these astoundingly important ideas might be better received if put in the context of a novel with snappy dialogue and lots of horrific violence.
No horrific violence here, nor snappy dialogue either. Just a clear and lucid explanation of a very complex subject. Few of us will ever find ourselves in a literal equivalent of the prisoner’s dilemma (PD), forced to decide whether to testify against a partner-in-crime to receive a lighter prison sentence. But we find ourselves in analogous situations literally every day, and mind you: I’ve double checked my usage of “literally” here and this time I’m sticking by it.
These PD situations are so omnipresent they are virtually invisible, as are the long-established cooperative equilibria that prevent all of us from continuously stabbing one another in the back as we fall into the alluring Nash equilibrium of mutual defection, leaving behind vast hordes of stabbed people and a few smug mathematicians mumbling “I told you so” as they tend to their wounds.
Even more important than providing a mathematical explanation of why (most) people aren't just total and complete pricks (please refrain from pointing out noteworthy exceptions. We all know some. Oftentimes I'm one of them.), and why we’ve been able to develop a complex society that could not exist without seemingly irrational altruism, modern game theory teaches us how we can create an even better society.
Cooperation has evolved over the course of millions of years by participants lacking the slightest knowledge of game theory, or, indeed, opposable thumbs. Evolution is a highly effective way to produce desirable results without any thought or effort whatsoever, provided one has a few million years to spare and doesn’t mind a lot of pain and suffering along the way. For beings with the cognitive abilities to understand the forces at play, they can achieve the same results far more efficiently.
It’s a very complex non-zero-sum game we’re all playing. We can all score a lot more points if we play it right.
……………………………
I’m going to stick in one last plug for my book, Practical Applications of Game Theory , which dramatizes an actual prisoner in prison facing a literal example of the prisoner’s dilemma. It's full of math, snappy dialogue, and, I should reiterate: horrific violence.
Um, Andy, I think you need to revisit the definitions of certain words, like “literally” and “overstating.”
OK, granted. But the implications of the game theory research and analysis presented here are so profoundly important, it’s difficult not to descend into hyperbole. Or ascend, as the case may be. Sure, at first glance it appears to be an account of legions of math and computer nerds trying to beat one another at a silly game. Who would suspect that these nerds may have essentially discovered the philosophical glue that holds all of society together? And done so with programs written in just a handful of code lines written in BASIC and FORTRAN, no less?
I did, but I cheated, of course. I was already convinced of game theory’s profound significance before I ever picked this up. I was doing research, reading everything I could find on the subject for my own book about game theory, my premise being that these astoundingly important ideas might be better received if put in the context of a novel with snappy dialogue and lots of horrific violence.
No horrific violence here, nor snappy dialogue either. Just a clear and lucid explanation of a very complex subject. Few of us will ever find ourselves in a literal equivalent of the prisoner’s dilemma (PD), forced to decide whether to testify against a partner-in-crime to receive a lighter prison sentence. But we find ourselves in analogous situations literally every day, and mind you: I’ve double checked my usage of “literally” here and this time I’m sticking by it.
These PD situations are so omnipresent they are virtually invisible, as are the long-established cooperative equilibria that prevent all of us from continuously stabbing one another in the back as we fall into the alluring Nash equilibrium of mutual defection, leaving behind vast hordes of stabbed people and a few smug mathematicians mumbling “I told you so” as they tend to their wounds.
Even more important than providing a mathematical explanation of why (most) people aren't just total and complete pricks (please refrain from pointing out noteworthy exceptions. We all know some. Oftentimes I'm one of them.), and why we’ve been able to develop a complex society that could not exist without seemingly irrational altruism, modern game theory teaches us how we can create an even better society.
Cooperation has evolved over the course of millions of years by participants lacking the slightest knowledge of game theory, or, indeed, opposable thumbs. Evolution is a highly effective way to produce desirable results without any thought or effort whatsoever, provided one has a few million years to spare and doesn’t mind a lot of pain and suffering along the way. For beings with the cognitive abilities to understand the forces at play, they can achieve the same results far more efficiently.
It’s a very complex non-zero-sum game we’re all playing. We can all score a lot more points if we play it right.
……………………………
I’m going to stick in one last plug for my book, Practical Applications of Game Theory , which dramatizes an actual prisoner in prison facing a literal example of the prisoner’s dilemma. It's full of math, snappy dialogue, and, I should reiterate: horrific violence.
December 27, 2015
Evidence that cooperation comes from selfishness.
January 18, 2026
In a nutshell the book argues that cooperation can emerge and persist. Using repeated Prisoner’s Dilemma tournaments, Axelrod shows that simple strategies outperform complex ones: tit-for-tat—start by cooperating, then mirror the other player’s last move—proves especially robust. It won the first tournament. Then when the lessons were learned, new strategies participated in the 2nd tournament and tit-for-tat still won (it’s robust).
Does this research teach people how to act in society? Well, yes. The author summarized it into 4 lessons, the last 3 of which quite are straightforward: don’t be the first to defect; reciprocate both cooperation and defection; don’t be too clever. The first lesson is a bit subtle. It is “don’t be envious”. The point here is you shouldn’t compare your result with someone else’s: that’s not just due to adopting different strategies.
Other than these key points, there are quite a bit of (nerdy) details: 1. Scholars love to use tournament. But they understand the results depend on the payback parameters and in real life, the system is more like a territorial system rather than a tournament (where only neighbors interact). So don’t over-interpret the experiment. Nevertheless, tit-for-tat is found to be hard to invade in a territorial system.
2. Real-world phenomena such as the live-let-live arrangement emerged in WWI trenches lend credence to the argument that cooperation can easily emerge and persist.
3. Reputation and label in a society allow people in the real world to use prediction rather than strictly follow tit-for-tat.
Does this research teach people how to act in society? Well, yes. The author summarized it into 4 lessons, the last 3 of which quite are straightforward: don’t be the first to defect; reciprocate both cooperation and defection; don’t be too clever. The first lesson is a bit subtle. It is “don’t be envious”. The point here is you shouldn’t compare your result with someone else’s: that’s not just due to adopting different strategies.
Other than these key points, there are quite a bit of (nerdy) details: 1. Scholars love to use tournament. But they understand the results depend on the payback parameters and in real life, the system is more like a territorial system rather than a tournament (where only neighbors interact). So don’t over-interpret the experiment. Nevertheless, tit-for-tat is found to be hard to invade in a territorial system.
2. Real-world phenomena such as the live-let-live arrangement emerged in WWI trenches lend credence to the argument that cooperation can easily emerge and persist.
3. Reputation and label in a society allow people in the real world to use prediction rather than strictly follow tit-for-tat.
September 1, 2018
This is a great book to read to get a deep understanding of how cooperation evolves and how to promote it. Most of the theory is based on simulations of the prisoner's dilemma game, with different strategies being empirically tested and strategies most similar to 'tit-for-tat' coming out far ahead. It's important to be 'nice' and avoid being the first to defect. It's also important to respond in turn, and cooperate while the cooperation is returned, but to 'defect' if your cooperation is responded to with defection. This prevents being taken advantage of by players using 'mean' strategies and sends a clear signal that defection won't be tolerated.
Unfortunately, unclear signals (signals that are too late or badly communicated) can create misperceptions about the intention of other players. Misperception can cause problems, and often create an 'echo chamber' of defection. For this reason, strategies that were also forgiving were more successful as they were able to revert back to patterns of cooperation.
Cooperation can evolve in many ways within species and organizations. In many cases it doesn't even require trust to evolve - only a durable relationship that will continue indefinitely and a memory of past interactions with different players. Many of the conclusions from this book were encouraging - cooperative strategies can form and thrive effectively in many different conditions.
Unfortunately, unclear signals (signals that are too late or badly communicated) can create misperceptions about the intention of other players. Misperception can cause problems, and often create an 'echo chamber' of defection. For this reason, strategies that were also forgiving were more successful as they were able to revert back to patterns of cooperation.
Cooperation can evolve in many ways within species and organizations. In many cases it doesn't even require trust to evolve - only a durable relationship that will continue indefinitely and a memory of past interactions with different players. Many of the conclusions from this book were encouraging - cooperative strategies can form and thrive effectively in many different conditions.
August 6, 2018
This book is phenomenal, it is in the same vein as and even reuses studies from Richard Dawkins’ Selfish Gene.
If you don’t have time or would rather not purchase this book, check out Axelrod’s paper “The Evolution of Norms”
If you don’t have time or would rather not purchase this book, check out Axelrod’s paper “The Evolution of Norms”
November 12, 2015
In a world where a book sells for its cover, it is easy to grab a book titled "The cure for cancer" and read a love story about a dying girl. It is easy to underestimate this book by its title. Don't.
A mathematical formula, expressing that cooperation increases with the number of interactions, is applied against competing algorithms on a tournament and wins. More tournaments follow, the formula is applied to other sciences and it remains working.
How can such a complex thing like the "cooperation among individuals" boil down to such simple terms? Guess we just have to live to see it proven wrong. Or right.
A mathematical formula, expressing that cooperation increases with the number of interactions, is applied against competing algorithms on a tournament and wins. More tournaments follow, the formula is applied to other sciences and it remains working.
How can such a complex thing like the "cooperation among individuals" boil down to such simple terms? Guess we just have to live to see it proven wrong. Or right.
March 24, 2024
The lesson is that not being nice may look promising at first, but in the long run it can destroy the very environment it needs for its own success. (S. 117)
The Evolution of Cooperation von Robert Axelrod wurde 1984 erstveröffentlicht und basiert auf verschiedenen Essays, die ab 1980 von ihm in verschiedenen Journals, darunter Science, veröffentlicht wurden. Die dem wissenschaftlichen Werk zugrunde liegenden Ergebnisse entspringen zwei Computerturnieren, bei denen verschiedene „Spielstrategien“ in wiederholten Gefangenendilemmata (Iterated Prisoners Dilemma=IPD) gegeneinander antraten. Die bedeutsame Erkenntnis aus den Versuchen ist, dass Kooperation zu deutlich besseren Ergebnissen führt als Verrat.
Ich beginne mit einer kurzen Zusammenfassung des Gefangenendilemmas und der üblichen, auch von Axelrod verwendeten Auszahlungsmatrix. Zwei Spieler können zwischen den Optionen Kooperieren (Cooperate=C) und Verrat (Defect=D) entscheiden. Es ist keinerlei Kommunikation möglich. Bei gemeinsamer Kooperation erhalten beide Spieler 3 Punkte (Reward=R), bei gemeinsamem Verrat 1 Punkt (Punishment=P). Verrät Spieler A, während Spieler B kooperiert, erhält er 5 Punkte (Temptation to defect=T), Spieler B erhält dann 0 Punkte (Sucker’s Payoff=S). Man beachte, dass bei einem einzelnen Spiel, unabhängig vom Verhalten des anderen Spielers, Verrat für einen Spieler stets die höhere Punktzahl liefert.
Relevant für das Verständnis von Axelrods Ergebnissen ist jedoch, dass die insgesamt ausgeschütteten Punkte bei gemeinsamer Kooperation mit R+R=6 höher liegen als bei einseitigem Verrat mit T+S=5, und deutlich über beidseitigem Verrat mit P+P=2. So ist es zu erklären, dass wenn mehrere Runden gespielt werden, und sich Spieler das bisherige Verhalten des Gegenübers merken können, ganz neue Dynamiken entstehen. Es wurden beim ersten Turnier pro Spiel genau 200 Runden, beim zweiten etwa 150 Runden mit einem zufällig bestimmten Ende gespielt.
Eine wichtige Bedingung muss erfüllt werden, damit ein IPD möglich wird, und diese tauft Axelrod „Schatten der Zukunft" (discount parameter=w). Er beschreibt zugleich die Gewichtung der folgenden Runde im Vergleich zur jetzigen und die Wahrscheinlichkeit, dass es bei einem Spiel mit zufällig bestimmtem Ende eine nächste Runde geben wird. Wenn nämlich ein erneutes Zusammentreffen unwahrscheinlich erscheint, wird D gegenüber C attraktiver. Auch außerhalb des Kontexts der Computerturniere lässt sich beobachten, dass die meisten Menschen einen sofortigen Gewinn einem möglichen, leicht höheren zukünftigen Gewinn vorziehen. Der Schatten der Zukunft muss also ausreichend hoch sein, damit Kooperation möglich ist.
Die Spielstrategien für die Turniere wurden von Wissenschaftlern aus den unterschiedlichsten Disziplinen wie den Wirtschaftswissenschaften, der Biologie, der Psychologie, der Soziologie oder den Computerwissenschaften in der Form von Algorithmen nach dem Muster: „Wenn X dann wähle C, ansonsten D…“ eingereicht. Die Länge der Algorithmen reichte dabei von fünf bis 152 Kommandos und wurden während des Turniers nicht mehr angepasst. Am ersten Turnier nahmen 15 Strategien teil, am zweiten Turnier 63. Jede Strategie spielte je fünf Spiele gegen jede andere Strategie und gegen sich selbst.
Wie können einzelne Strategien nun aussehen? Hier ein paar Beispiele und Namen, die im Buch häufig vorkommen:
1. RANDOM: Zufällige Wahl zwischen C und D
2. ALL D: Immer D
3. FRIEDMAN: Immer C, aber nach einem D des Gegenspielers dauerhaft D (Permanente Bestrafung)
4. TIT FOR TAT: Erster Zug C, dann stets die Option, die der Gegenspieler im vorherigen Zug gewählt hat („Wie du mir, so ich dir“ oder „Auge um Auge“)
5. JOSS: Wie TIT FOR TAT, aber mit einer 10% Chance D zu wählen, wenn der Gegenspieler zuvor C wählte
6. DOWNING: Komplexer Algorithmus, der versucht die Wahrscheinlichkeit zu errechnen, dass der Gegenspieler ein D von DOWNING mit D vergilt, und dann versucht, möglichst oft D zu spielen, wenn er damit davonkommt, sonst jedoch C wählt
Sind die Ergebnisse, die in Kapitel eins sowie im Anhang A sehr genau dargestellt werden, die überaus lange Einführung dieser Besprechung wert? In meinen Augen absolut, denn sie können die Sicht auf die Welt verändern. Das erste Turnier mit 15 Teilnehmern gewann die simple Strategie TIT FOR TAT, außerdem haben die erfolgreichsten acht nie zuerst verraten (nice=nett), während die schlechtesten sieben allesamt zuerst verraten haben (bad=böse). Unerwartet, was für eine Erkenntnis! Vielleicht ein Zufall?
Mit den Ergebnissen des ersten Turniers ausgestattet konnten für das zweite Turnier alte, neue, oder überarbeitete Strategien eingereicht werden. Insgesamt gab es nun ganze 63 Teilnehmer. Während die Komplexität der Programme keine Korrelation mit dem Erfolg aufwies, war eine andere Korrelation mehr als deutlich: Es lohnt sich wirklich, nett zu sein. Unter den fünfzehn erfolgreichsten Strategien des zweiten Turniers war nur eine böse, und diese erreichte nur den achten Platz. Die fünfzehn schlechtesten Plätze hingegen wurden von vierzehn bösen Strategien belegt! TIT FOR TAT gewann erneut das Turnier. Wahnsinn!
Spulen wir vor, denn Axelrod hat über die Jahre viele weitere Untersuchungen und Simulationen unternommen. Neben der Erkenntnis, dass sich Kooperation lohnt, formuliert Axelrod in Kapitel sechs vier konkrete Empfehlungen für Spieler in wiederholten Gefangenendilemmata. Zusammengefasst lauten diese:
1. Don’t be envious. (Da es sich nicht um ein Nullsummenspiel handelt, spielt es keine Rolle, wer in der direkten Begegnung mehr Punkte erhält; das Ziel ist, über die Begegnung mit möglichst vielen anderen Strategien hinweg viele Punkte zu erreichen.)
2. Don’t be the first to defect. (Während Verrat im ersten Moment einen Vorteil bringt, wird man langfristig vom Gegenspieler hierfür bestraft. Außerdem zerstört diese Strategie bei evolutionärer Betrachtung langfristig die Umgebung, in der sie prosperiert, da leicht auszunützende Strategien aussterben.)
3. Reciprocate both cooperation and defection. (Kooperiere mit wohlwollenden Strategien, bestrafe solche sofort, die versuchen dich auszunutzen. Damit schützt du nicht nur dich selbst, sondern auch andere kooperative Strategien.)
4. Don’t be too clever. (Die Strategie muss für andere erkennbar sein und darf nicht mit zufälligem Handeln verwechselt werden)
(S. 110)
Nimmt man nun an, dass Kooperation etwas Positives und Gewolltes ist, so gibt es im Kapitel sieben auch Empfehlungen, wie Kooperation gefördert werden kann. Gegenbeispiele für Räume, in denen Kooperation ungewollt ist, gibt es im Übrigen auch, beispielsweise bei mafiösen Strukturen. Axelrods fünf konkreten Ansätze, wie Reformer in einer Gesellschaft Kooperation fördern können, lauten:
1. Enlarge the shadow of the future. (Menschliche Begegnungen müssen häufiger und wiederkehrender werden. Es braucht also mehr Berührung mit den Mitmenschen, besonders in Form enger und haltbarer Nachbarschaftsnetzwerke.)
2. Change the payoffs. (Gesetze und soziale Verträge [Rousseau] müssen Kooperation weiter belohnen und Ausbeutung ahnden.)
3. Teach people to care about each other. (Altruistisches Verhalten sollte als soziale Norm weitergegeben werden; andere Menschen gut zu behandeln löst bei den meisten Menschen sowieso positive Gefühle aus.)
4. Teach reciprocity. (Ausbeuterische Versuche müssen durch reziprokes Verhalten der anderen Menschen bzw. der Gesamtgesellschaft als solches schnell und deutlich geahndet werden. Wer „auch die andere Wange hinhält“ gefährdet also seine Mitmenschen.)
5. Improve recognition abilities. (Menschen können besonders gut andere Gesichter wiedererkennen, in Kleingruppen ist also die persönliche Historie von Verrat oder Kooperation etwas, das sich gemerkt wird. In modernen Gesellschaften, Großstädten oder auch im Internet müssen erst Methoden erschaffen werden, um „nette“ oder „böse“ Gegenüber zu erkennen.)
Eine weitere, in meinen Augen höchst interessante Erkenntnis aus den vielen Computerturnieren ist, dass TIT FOR TAT in allen einzelnen Spielen, im direkten Vergleich mit ihrem jeweiligen Gegenüber, nicht ein einziges Mal eine höhere Punktzahl erzielte. TIT FOR TAT hat stets entweder gleich viele oder etwas weniger Punkte als das Gegenüber erzielt. Dennoch siegte sie in der Gesamtwertung der Turniere fast immer und stellte im übrigen Turnier die zweiterfolgreichste Strategie dar.
Die neben dem generellen Erfolg von Kooperation bedeutendste Erkenntnis aus dem Werk, denn sie untermauert die konkrete Anwendbarkeit von kooperativen Strategien in der heutigen Welt, stellt für mich der evolutionäre bzw. territoriale Erfolg von Kooperation in weiteren Untersuchungen dar. Bei der territorialen Betrachtung wird angenommen, dass räumlich verteilte Spieler nach einigen Spielen beginnen, Strategien ihrer Nachbarn zu übernehmen, sofern diese erfolgreicher als ihre eigenen sind. Die evolutionäre Betrachtung nimmt an, dass sich Strategien mit hohen Punktzahlen über Generationen vermehren, während weniger erfolgreiche Strategien aussterben. Das Ergebnis: Ein kleiner Cluster kooperierender TIT FOR TAT kann in einer von ALL D dominierten Population bestehen, sich ausbreiten, dominant werden und diese Position gegen ein erneutes Eindringen von ALL-D-Clustern verteidigen.
Was mir besonders gut an diesem Buch gefallen hat, ist, dass die Erkenntnisse empirisch höchst belastbar, in wissenschaftlicher, aber recht einfacher Sprache dargebracht werden und vor allem Kritiker:innen aufgrund der Verortung des Autors nicht die Möglichkeit haben, die Erkenntnisse als „linke Verirrung“ oder „unrealistische Utopie“ abzutun. Alle empirischen Daten stammen aus den Computerturnieren und weiteren Versuchen mit IPDs. Einschränkend für die Übertragung in die materielle Welt sind dabei offensichtlich die (willkürlich) festgelegten Parameter der IPDs, bspw. die Höhe der Auszahlungsmatrix. Die Auswirkungen tatsächlicher menschlicher Interaktionen sind stets weniger fassbar und subtiler.
Es werden jedoch, um dieser Kritik zu begegnen, im Buch auch ausführliche Beispiele für realistische Anwendungsbereiche der Turnierergebnisse geliefert: Zusammenarbeit von Abgeordneten im amerikanischen Kongress, Missachten von Befehlen im Stellungskrieg des Ersten Weltkriegs oder Kooperation zwischen Individuen als evolutionäre Strategie – Bezüge zu Richard Dawkins’ The Selfish Gene, das zehn Jahre zuvor erschien, bietet hier nicht nur dessen Vorwort zu Beginn von The Evolution of Cooperation. Generell stützen sich Axelrods der rational choice theory zuordenbare Thesen und Dawkins genfokussierte Erklärung der Evolution gegenseitig.
Ich möchte diese Besprechung einer absoluten Leseempfehlung mit einem langen, aber mutmachenden Zitat beenden:
It is encouraging to see that cooperation can get started, can thrive in a variegated environment, and can protect itself once established. […] The individuals do not have to be rational: the evolutionary process allows the successful strategies to thrive, even if the players do not know why or how. […] Likewise, there is no need to assume trust between the players: the use of reciprocity can be enough to make defection unproductive. Altruism is not needed: successful strategies can elicit cooperation even from an egoist. Finally, no central authority is needed: cooperation based on reciprocity can be self-policing. (S. 173f)
November 3, 2010
A very good book that makes me interested in reading more game theory. The first two chapters are a bit dense (but really not too bad) as Axelrod goes over the "Computer Prisoner's Dilemma Tournament" that sparked this book. These chapters are an analysis of computer programs (not as dull as it sounds), but it proves to be the evidence for his theory and the meat of the book.
A quick synopsis of the book: In the late 70s, Axelrod, a University of Michigan poli sci professor, held a Computer Tournament. The Computer Tournament invited participants to create computer programs to wage battle in a Prisoner's Dilemma. A Prisoner's Dilemma is one of the foundational game theory scenarios/models. In it two prisoners are caught and are being interrogated. Each prisoner has two options. They can either keep quiet (cooperate with their accomplice) or they can rat on their accomplice (defect). As each prisoner has two options, there are four possible results: mutual cooperation (CC), mutual defection (DD), or defection/cooperation (CD or DC) by either of the two prisoners. Game theorists have assigned points to these results--if both prisoners cooperate they both get minimal sentences (3 points). If both defect they get strict sentences (each gets 1 point). If one cooperates and the other defects, the cooperator receives a life sentence (0 points) while the defector gets freedom (5 points). The conclusion from this scenario is that it is in each of the prisoner's best interests to rat out their accomplice. If they rat out their accomplice they are guaranteed at least some points. Sure, they receive a harsh sentence if their partner also defects--but if their partner doesn't defect they get freedom! The best result of all. And more importantly, if they cooperate, they risk getting the harshest sentence--life in prison. So what often ends up happening with rational actors is that they both end up with harsh sentences (mutual defection) rather than the more appealing and mutual-beneficial light sentences (mutual cooperation). The Prisoner's Dilemma explains that in acting rationally, actors often forgo mutually beneficial solutions. Downer of a conclusion.
But in steps Axelrod. Axelrod, with the clarity of a political scientist, makes a plain and convincing argument. He answers this book's central question: in a world of egoists without a central authority (some power to force or incentivize), how did cooperation ever come to exist? The key to cooperation is ensuring that a relationship is sufficiently long. He makes this point clearer than I can:
"What makes it possible for cooperation to emerge is the fact that the players might meet again. This possibility means that the choices made today not only determine the outcome of this move, but can also influence the later choices of the players. The future can therefore cast a shadow back upon the present and thereby affect the current strategic situation."
In short, people have incentive to cooperate if they meet again and again. If the prisoner's dilemma is run indefinitely (tens, hundreds, thousands of times), then pretty soon people will realize that it's in their best interest to cooperate rather than mutually defect. The two rounds of Axelrod's Prisoners' Dilemma Computer Tournament back this up. The highest finishers are the "nice programs" and the winner of both tournaments is "Tit for Tat" (T4T)--a program that cooperates with its partner on the first move, and then copies whatever it's partner's previous move was. As a result, T4T is never the first to defect and therefore can build a cooperative relationship with other programs. But at the same time, if T4T meets a "mean program" it will respond to defection with defection of its own. So it's no pushover.
I've already gone into too much detail with Axelrod's theory and results, but that's only a testament to how easily understood his ideas are. Pick up the book for more details--chapter 6, "Advice for Participants and Reformers" is particularly good.
A few thoughts on the book in general: at times I thought this book could be significantly shortened so that it was a long academic article. The book itself is pretty short (~190 pages) and Axelrod repeats the same main points over and over. I really enjoyed this repetition, as I felt like I had a firmer understanding of it each time he repeated it. But nonetheless, I think this book could've been a long journal article without losing too much important information. Also, I'd be interested to see this applied to international relations issues. In some ways I'm glad that Axelrod didn't do this himself--otherwise, he would've stamped a Cold War mentality on to his book. The book and its theory seems purer without too many real world applications. But I'd still love to read other people's use of and twists on this theory when applied to international relations.
Lastly, I know this isn’t a self-help book. I know that life is more complex than game theory, but there are things from this book that are helpful/tempting for me to apply to life. And Axelrod encourages this. In the last pages of his conclusion, he writes, "Perhaps it is not too much to hope that people can use the surrogate experience of the Computer Tournament to learn the value of reciprocity for their own Prisoner’s Dilemma interactions” (189). But I'll take these with a grain of salt: people are more complex than computers.
Nonetheless, the idea that life is not a zero-sum game is important to be reminded of. What's more, the fact that T4T, won the tournament and yet lost every single interaction it had resonated. It won by cooperating and establishing mutually beneficial relationships (which it slightly lost/tied), not by defeating its opponents. And the last take away point I'll keep is that, reciprocity is important to interactions. If a partner cooperates, you cooperate. And if someone defects, you respond immediately and clearly with defection of your own. Responding to defection with defection seems sort of rash--especially since it can be tough to interpret other people's actions--but T4T makes a convincing argument that reciprocity is the most stable strategy in a wide range of environments.
In short, this simple read provides a lot of tempting fluff for real world interactions and makes me excited to pick up some more game theory.
A quick synopsis of the book: In the late 70s, Axelrod, a University of Michigan poli sci professor, held a Computer Tournament. The Computer Tournament invited participants to create computer programs to wage battle in a Prisoner's Dilemma. A Prisoner's Dilemma is one of the foundational game theory scenarios/models. In it two prisoners are caught and are being interrogated. Each prisoner has two options. They can either keep quiet (cooperate with their accomplice) or they can rat on their accomplice (defect). As each prisoner has two options, there are four possible results: mutual cooperation (CC), mutual defection (DD), or defection/cooperation (CD or DC) by either of the two prisoners. Game theorists have assigned points to these results--if both prisoners cooperate they both get minimal sentences (3 points). If both defect they get strict sentences (each gets 1 point). If one cooperates and the other defects, the cooperator receives a life sentence (0 points) while the defector gets freedom (5 points). The conclusion from this scenario is that it is in each of the prisoner's best interests to rat out their accomplice. If they rat out their accomplice they are guaranteed at least some points. Sure, they receive a harsh sentence if their partner also defects--but if their partner doesn't defect they get freedom! The best result of all. And more importantly, if they cooperate, they risk getting the harshest sentence--life in prison. So what often ends up happening with rational actors is that they both end up with harsh sentences (mutual defection) rather than the more appealing and mutual-beneficial light sentences (mutual cooperation). The Prisoner's Dilemma explains that in acting rationally, actors often forgo mutually beneficial solutions. Downer of a conclusion.
But in steps Axelrod. Axelrod, with the clarity of a political scientist, makes a plain and convincing argument. He answers this book's central question: in a world of egoists without a central authority (some power to force or incentivize), how did cooperation ever come to exist? The key to cooperation is ensuring that a relationship is sufficiently long. He makes this point clearer than I can:
"What makes it possible for cooperation to emerge is the fact that the players might meet again. This possibility means that the choices made today not only determine the outcome of this move, but can also influence the later choices of the players. The future can therefore cast a shadow back upon the present and thereby affect the current strategic situation."
In short, people have incentive to cooperate if they meet again and again. If the prisoner's dilemma is run indefinitely (tens, hundreds, thousands of times), then pretty soon people will realize that it's in their best interest to cooperate rather than mutually defect. The two rounds of Axelrod's Prisoners' Dilemma Computer Tournament back this up. The highest finishers are the "nice programs" and the winner of both tournaments is "Tit for Tat" (T4T)--a program that cooperates with its partner on the first move, and then copies whatever it's partner's previous move was. As a result, T4T is never the first to defect and therefore can build a cooperative relationship with other programs. But at the same time, if T4T meets a "mean program" it will respond to defection with defection of its own. So it's no pushover.
I've already gone into too much detail with Axelrod's theory and results, but that's only a testament to how easily understood his ideas are. Pick up the book for more details--chapter 6, "Advice for Participants and Reformers" is particularly good.
A few thoughts on the book in general: at times I thought this book could be significantly shortened so that it was a long academic article. The book itself is pretty short (~190 pages) and Axelrod repeats the same main points over and over. I really enjoyed this repetition, as I felt like I had a firmer understanding of it each time he repeated it. But nonetheless, I think this book could've been a long journal article without losing too much important information. Also, I'd be interested to see this applied to international relations issues. In some ways I'm glad that Axelrod didn't do this himself--otherwise, he would've stamped a Cold War mentality on to his book. The book and its theory seems purer without too many real world applications. But I'd still love to read other people's use of and twists on this theory when applied to international relations.
Lastly, I know this isn’t a self-help book. I know that life is more complex than game theory, but there are things from this book that are helpful/tempting for me to apply to life. And Axelrod encourages this. In the last pages of his conclusion, he writes, "Perhaps it is not too much to hope that people can use the surrogate experience of the Computer Tournament to learn the value of reciprocity for their own Prisoner’s Dilemma interactions” (189). But I'll take these with a grain of salt: people are more complex than computers.
Nonetheless, the idea that life is not a zero-sum game is important to be reminded of. What's more, the fact that T4T, won the tournament and yet lost every single interaction it had resonated. It won by cooperating and establishing mutually beneficial relationships (which it slightly lost/tied), not by defeating its opponents. And the last take away point I'll keep is that, reciprocity is important to interactions. If a partner cooperates, you cooperate. And if someone defects, you respond immediately and clearly with defection of your own. Responding to defection with defection seems sort of rash--especially since it can be tough to interpret other people's actions--but T4T makes a convincing argument that reciprocity is the most stable strategy in a wide range of environments.
In short, this simple read provides a lot of tempting fluff for real world interactions and makes me excited to pick up some more game theory.
March 23, 2022
This book is wholly and totally concerned with the (iterated) Prisoner's Dilemma. In case you don't know, the Prisoner's Dilemma is a mathematical game analyzed in Game Theory. Albert W. Tucker presented it as follows:
"Two members of a criminal organization are arrested and imprisoned. Each prisoner is in solitary confinement with no means of communicating with the other. The prosecutors lack sufficient evidence to convict the pair on the principal charge, but they have enough to convict both on a lesser charge. Simultaneously, the prosecutors offer each prisoner a bargain. Each prisoner is given the opportunity either to betray the other by testifying that the other committed the crime, or to cooperate with the other by remaining silent. The possible outcomes are:
The punishments could of course also be configured differently. But what makes this situation really interesting is to let these two prisoners meet again and again in the same situation while they are fully aware of the actions the other prisoner took in the past interactions. This, then, is called the Iterated Prisoner's Dilemma.
Axelrod wanted to know which strategies would get the best result in such an iterated game, especially when the total number of rounds to be played would not be known by the players in advance. To find this out he organized a tournament in which people from different disciplines should submit strategies to be used by the players in the game. He then let those strategies play against each other.
Although there is no strategy that always gets the best result, as the success is dependent on the kind of strategy the other player is using, one strategy has emerged as a clear winner in Axelrod's tournaments. This strategy is called Tit for Tat. This strategy is very simple and works like this: the player initially cooperates and afterwards always replicates the action of the other player in the last move. This means there is always an equivalent retaliation for defections. But what makes this strategy so successful? First of all, it is nice: It is never the first to defect which means it prevents unnecessary trouble (for example if the other player also uses a nice strategy). The second thing is, it is provocable: If it is defected against, it retaliates with the next occasion, which should discourage the other side from continuing defecting. Another important property of the strategy is that it is forgiving, meaning it does not keep defecting if the other side is cooperating after defection. This allows to restore mutual cooperation. Finally, Tit for Tat is a clear and easy to recognize strategy. Once the other player sees the pattern behind the strategy, it can easily realize that cooperation is the best way of dealing with it.
You might think that these theoretical games are far removed from reality, but the author successfully shows that this is not the case. A real-life example of the Prisoner's Dilemma was seen in the trench warfare in France during WW1. There a live-and-let-live system, that is described in more detail in the book, emerged between the enemy fronts. This shows that cooperation can emerge even between antagonists under suitable circumstances.
Furthermore, there are also a great deal of interesting examples from the field of biology. The author puts cooperation in a evolutionary perspective and shows how it is likely to have evolved even in environments of competition and selfish actors.
What starts as interesting theoretical games in the first half of book, turns into solid wisdom applicable to many situations in life in the last chapters. While most people think about life as a zero-sum game, actually most of the time this is not the case. There are countless situations where both sides can do well and mutual cooperation would be possible. The only thing standing in the way of this often times is envy and the thinking that one must be more successful than the other to be successful. The results of the tournament teach an important lesson here:
"TIT FOR TAT achieves either the same score as the other player, or a little less. TIT FOR TAT won the tournament, not by beating the other player, but by eliciting behavior from the other player which allowed both to do well. TIT FOR TAT was so consistent at eliciting mutually rewarding outcomes that it attained a higher overall score than any other strategy."
Besides giving the reader a small taste of the world of game theory, this book offers a lens through which many interactions can be understood and it proposes concrete measures to increase the chances for successful cooperation in different situations. It also makes for an overall interesting read and is still very relevant even though it was published in 1984.
"Two members of a criminal organization are arrested and imprisoned. Each prisoner is in solitary confinement with no means of communicating with the other. The prosecutors lack sufficient evidence to convict the pair on the principal charge, but they have enough to convict both on a lesser charge. Simultaneously, the prosecutors offer each prisoner a bargain. Each prisoner is given the opportunity either to betray the other by testifying that the other committed the crime, or to cooperate with the other by remaining silent. The possible outcomes are:
- If A and B each betray the other, each of them serves two years in prison
- If A betrays B but B remains silent, A will be set free and B will serve three years in prison
- If A remains silent but B betrays A, A will serve three years in prison and B will be set free
- If A and B both remain silent, both of them will serve only one year in prison (on the lesser charge)".
The punishments could of course also be configured differently. But what makes this situation really interesting is to let these two prisoners meet again and again in the same situation while they are fully aware of the actions the other prisoner took in the past interactions. This, then, is called the Iterated Prisoner's Dilemma.
Axelrod wanted to know which strategies would get the best result in such an iterated game, especially when the total number of rounds to be played would not be known by the players in advance. To find this out he organized a tournament in which people from different disciplines should submit strategies to be used by the players in the game. He then let those strategies play against each other.
Although there is no strategy that always gets the best result, as the success is dependent on the kind of strategy the other player is using, one strategy has emerged as a clear winner in Axelrod's tournaments. This strategy is called Tit for Tat. This strategy is very simple and works like this: the player initially cooperates and afterwards always replicates the action of the other player in the last move. This means there is always an equivalent retaliation for defections. But what makes this strategy so successful? First of all, it is nice: It is never the first to defect which means it prevents unnecessary trouble (for example if the other player also uses a nice strategy). The second thing is, it is provocable: If it is defected against, it retaliates with the next occasion, which should discourage the other side from continuing defecting. Another important property of the strategy is that it is forgiving, meaning it does not keep defecting if the other side is cooperating after defection. This allows to restore mutual cooperation. Finally, Tit for Tat is a clear and easy to recognize strategy. Once the other player sees the pattern behind the strategy, it can easily realize that cooperation is the best way of dealing with it.
You might think that these theoretical games are far removed from reality, but the author successfully shows that this is not the case. A real-life example of the Prisoner's Dilemma was seen in the trench warfare in France during WW1. There a live-and-let-live system, that is described in more detail in the book, emerged between the enemy fronts. This shows that cooperation can emerge even between antagonists under suitable circumstances.
Furthermore, there are also a great deal of interesting examples from the field of biology. The author puts cooperation in a evolutionary perspective and shows how it is likely to have evolved even in environments of competition and selfish actors.
What starts as interesting theoretical games in the first half of book, turns into solid wisdom applicable to many situations in life in the last chapters. While most people think about life as a zero-sum game, actually most of the time this is not the case. There are countless situations where both sides can do well and mutual cooperation would be possible. The only thing standing in the way of this often times is envy and the thinking that one must be more successful than the other to be successful. The results of the tournament teach an important lesson here:
"TIT FOR TAT achieves either the same score as the other player, or a little less. TIT FOR TAT won the tournament, not by beating the other player, but by eliciting behavior from the other player which allowed both to do well. TIT FOR TAT was so consistent at eliciting mutually rewarding outcomes that it attained a higher overall score than any other strategy."
Besides giving the reader a small taste of the world of game theory, this book offers a lens through which many interactions can be understood and it proposes concrete measures to increase the chances for successful cooperation in different situations. It also makes for an overall interesting read and is still very relevant even though it was published in 1984.
October 13, 2021
Актуальная для децентрализованных сообществ тема кооперации без контроля сверху. Теория, рассуждения и практические примеры в политике, войне, повседневной жизни, биологии
February 2, 2013
I know some basic game theory, so I thought that this book would be redundant. Yes, I get it - Tit-For-Tat is the winning strategy in iterated Prisoners' Dilemma games, etc. I frankly bought the book because I found it for cheap and I decided to actually read it because it's a seminal piece of work.
But once I started, I could not put this book down. It was at times very uplifting and at other times horrifying. I was so engrossed that it took real discipline to remind myself throughout that the conclusions being drawn stem from simulations that require very important assumptions that are not present in many types of interactions. It's to the author's credit that the book was so engrossing that I constantly had to catch myself over-enthusiastically misapplying its lessons.
In some respects the book is incomplete. For instance, (1)the author rightly advises someone in a PD to maximize one's her own benefit rather than base her success on how she compares to the other player (in fact, one of the interesting and in retrospect obvious points is that Tit-for-Tat will never do better than the particular partner it is playing with). This is sound advice, even if it may run contrary to some hardwired behavioral tendencies (e.g.: see Mansbridge, ed., Beyond Self-Interest for some arguments to that effect), but it dismisses the possibility that there is a meta-game going on, in which someone with a sufficiently large proportion of "points" may then try to coerce the other. In practical terms: it's great if both of our living standards increase, but if yours increases at a rate that far exceeds mine, I may need to defect in order to prevent future domination. This would not be possible in a PD proper, but Axelrod points out that his analysis does not require payoffs to be symmetric (p.17). To take another example, (2)the author demonstrates that short time horizons are conducive to increased rational likelihood of defection, whether we are microbes or people. It turns out that getting old is a very dangerous thing to do, as formerly cooperative organisms will stop being so cooperative. So why don't we systematically screw over old people?
Of course, this is not in any way a critique of the book. And I am aware that these are elementary points. There are answers to these types of problems. With respect to (1), some might say that I just didn't describe a PD after all. Others might say that I did do so, but that it is a PD that is nested in a larger game. With respect to (2), there are certainly stories of social stability, etc., that can be told. I bring this up not to try to point out "flaws" (again: they are not flaws), but actually to say that even the "incomplete" bits left me fascinated.
I have no idea if this is objectively a five-star book, but I couldn't give it anything less given its importance and the effect it had on me while I read it.
(edit: actually, I just remembered that he does address (1) to some extent in his discussion of the bombing of Pearl Harbor)
But once I started, I could not put this book down. It was at times very uplifting and at other times horrifying. I was so engrossed that it took real discipline to remind myself throughout that the conclusions being drawn stem from simulations that require very important assumptions that are not present in many types of interactions. It's to the author's credit that the book was so engrossing that I constantly had to catch myself over-enthusiastically misapplying its lessons.
In some respects the book is incomplete. For instance, (1)the author rightly advises someone in a PD to maximize one's her own benefit rather than base her success on how she compares to the other player (in fact, one of the interesting and in retrospect obvious points is that Tit-for-Tat will never do better than the particular partner it is playing with). This is sound advice, even if it may run contrary to some hardwired behavioral tendencies (e.g.: see Mansbridge, ed., Beyond Self-Interest for some arguments to that effect), but it dismisses the possibility that there is a meta-game going on, in which someone with a sufficiently large proportion of "points" may then try to coerce the other. In practical terms: it's great if both of our living standards increase, but if yours increases at a rate that far exceeds mine, I may need to defect in order to prevent future domination. This would not be possible in a PD proper, but Axelrod points out that his analysis does not require payoffs to be symmetric (p.17). To take another example, (2)the author demonstrates that short time horizons are conducive to increased rational likelihood of defection, whether we are microbes or people. It turns out that getting old is a very dangerous thing to do, as formerly cooperative organisms will stop being so cooperative. So why don't we systematically screw over old people?
Of course, this is not in any way a critique of the book. And I am aware that these are elementary points. There are answers to these types of problems. With respect to (1), some might say that I just didn't describe a PD after all. Others might say that I did do so, but that it is a PD that is nested in a larger game. With respect to (2), there are certainly stories of social stability, etc., that can be told. I bring this up not to try to point out "flaws" (again: they are not flaws), but actually to say that even the "incomplete" bits left me fascinated.
I have no idea if this is objectively a five-star book, but I couldn't give it anything less given its importance and the effect it had on me while I read it.
(edit: actually, I just remembered that he does address (1) to some extent in his discussion of the bombing of Pearl Harbor)
This entire review has been hidden because of spoilers.
February 9, 2010
Robert Axelrod’s “The Evolution of Cooperation” is a classic in our understanding of why cooperation occurs in humans. The book begins with a simple question (Page vii): “When should a person cooperate, and when should that person be selfish, in an ongoing interaction with another person?” The ultimate explanation for the choice, according to Axelrod (and evolutionary theorist William Hamilton) is evolution. This is thoroughly discussed in Chapter 5, which outlines how cooperation could evolve as an adaptive behavior within a species.
One key part of this book is a round robin tournament in which a variety of strategies are tested in an “Iterated Prisoner’s Dilemma” game. Prisoner’s Dilemma is a game among the variety of those used in what is called Game Theory. The premise is simple: two thieves have been caught by the police. The policy offer a deal: Rat out your partner, s/he gets a tough sentence and the turncoat gets off. If both rat one another out, they both get a tougher sentence (although not as bad as if one person keeps quiet and the other one squeals). The assumption is that neither trusts the other; they rat one another out; they are both worse off than if they had kept their mouths shut.
One approach to Prisoner’s Dilemma that did the best was Anatol Rapoport’s entry, “TIT FOR TAT.” Here, one keeps one’s mouth shut, for example, as long as one’s confederate does not rat him/her out. If the other person rats one out, you turn the tables and rat him/her out. If the other player quits ratting out, then one ceases ratting the other out. This was the simplest of the entries, according to Axelrod. But it is the one that worked best. In short, cooperate as long as the other player cooperates; be nasty when the other player is nasty; don’t hold grudges and keep punishing if the other person begins cooperating.
Of course, things are actually more complex than this, but the above gives a sense of the nature of the winning strategy. It does raise questions about the common assumption that everyone is selfish and will always do what is needed to advance one’s interests at the expense of others. It begins to raise approaches to understanding “altruism,” self-sacrifice that benefits others (and would also benefit the altruist in the long run).
At any rate, this is a thought provoking book and a genuine classic, with many applications in public life and in our own daily lives.
One key part of this book is a round robin tournament in which a variety of strategies are tested in an “Iterated Prisoner’s Dilemma” game. Prisoner’s Dilemma is a game among the variety of those used in what is called Game Theory. The premise is simple: two thieves have been caught by the police. The policy offer a deal: Rat out your partner, s/he gets a tough sentence and the turncoat gets off. If both rat one another out, they both get a tougher sentence (although not as bad as if one person keeps quiet and the other one squeals). The assumption is that neither trusts the other; they rat one another out; they are both worse off than if they had kept their mouths shut.
One approach to Prisoner’s Dilemma that did the best was Anatol Rapoport’s entry, “TIT FOR TAT.” Here, one keeps one’s mouth shut, for example, as long as one’s confederate does not rat him/her out. If the other person rats one out, you turn the tables and rat him/her out. If the other player quits ratting out, then one ceases ratting the other out. This was the simplest of the entries, according to Axelrod. But it is the one that worked best. In short, cooperate as long as the other player cooperates; be nasty when the other player is nasty; don’t hold grudges and keep punishing if the other person begins cooperating.
Of course, things are actually more complex than this, but the above gives a sense of the nature of the winning strategy. It does raise questions about the common assumption that everyone is selfish and will always do what is needed to advance one’s interests at the expense of others. It begins to raise approaches to understanding “altruism,” self-sacrifice that benefits others (and would also benefit the altruist in the long run).
At any rate, this is a thought provoking book and a genuine classic, with many applications in public life and in our own daily lives.
July 26, 2021
¿Porqué cooperamos? ¿Porque a veces nos traicionan? Es mejor seguir las reglas o ser un estafador? Es por las castigos o por algo más.
Este libro explora como diferentes programas de computación generan interacciones y dependiendo de ellos algunos gana o no. Adivinen, los que mejores dan resultados son los que cooperan y son "buenas personas". El gran mensaje es que al coorperar realmente ganamos en una sociedad o grupo de personas.
Es un libro fascinante.
R.
Este libro explora como diferentes programas de computación generan interacciones y dependiendo de ellos algunos gana o no. Adivinen, los que mejores dan resultados son los que cooperan y son "buenas personas". El gran mensaje es que al coorperar realmente ganamos en una sociedad o grupo de personas.
Es un libro fascinante.
R.
March 13, 2023
"El verdadero fundamento de la cooperación no es la confianza, sino la perdurabilidad de la relación".
Un libro sobre teoría de juegos revestido de expresiones de carácter ético que trata de demostrar una suerte de principio ético-matemático que no formula jamás.
Un libro sobre teoría de juegos revestido de expresiones de carácter ético que trata de demostrar una suerte de principio ético-matemático que no formula jamás.
March 11, 2022
How to win the iterated prisoners dilemma?
Never defect first. After that, always reciprocate the opponents behavior. Want to know why? Read the book.
Nice book about game theory, more specifically about the iterated prisoners dilemma. It answers the question above and also what this means for our lives, organizations, nations, etc. Bit technical but not too much. Highly recommended.
Never defect first. After that, always reciprocate the opponents behavior. Want to know why? Read the book.
Nice book about game theory, more specifically about the iterated prisoners dilemma. It answers the question above and also what this means for our lives, organizations, nations, etc. Bit technical but not too much. Highly recommended.
July 13, 2021
Remarkably insightful for such a small book. Life and the world if full of iterated prisoner dilemmas and this book is great if you want to learn how to get better at solving them. The discussions on ecology, evolution, international conflict and the stability of hierarchy in labels was particularly illuminating.
November 3, 2012
Axelrod takes on the problem of how cooperation can emerge in a world of self-seeking egoists without a central authority. The question has important implications for the evolution of cooperation among inherently selfish organisms in biological systems.
Axelrod begins by examining the problem from the standpoint of game theory. Specifically, he considers how cooperation might emerge in the course of an iterated prisoner’s dilemma. The key here is that the game is iterated – that is, the players meet again and again. This means that choices not only determine the outcome of the present move, but can also influence the later choices of the players. So, for example, it does not necessarily pay to defect like it would in a single round match. Axelrod’s approach was to solicit strategies from colleagues and professionals across a range of academic fields, play them against each other, and examine the characteristics of those that performed best.
While continuing interaction between two players is necessary for cooperation to emerge, it is not sufficient. Axelrod identifies four properties that tend to make a strategy successful: it should be nice (it should never be the first to defect), retaliatory (it should defect when defected against), forgiving (it should cooperate when cooperation is sought), and have clear behavior so that the other player can recognize the strategy and adapt to it. One entry in the prisoner's dilemma "tournament" possessed all of these qualities and it proved to be the most successful strategy overall. Called TIT FOR TAT, the strategy cooperates until defected against, after which it defects until it is cooperated with again.
Axelrod’s use of the prisoner’s dilemma is beautiful in its simplicity and power – when filtered through the classic game-theoretic workhorse, of the wide range of possible strategies, successful schemes are found to have a small number of simple characteristics in common.
Armed with the results from these initial game-theoretic considerations, Axelrod turns to the emergence of cooperation in biology, drawing on the seminal work of biologist W. D. Hamilton. Of particular interest is the question of how certain modes of cooperation evolve within a population of individuals, and given a prevailing strategy for dealing with conflict, is it possible for alternative strategies to “invade” the population and shift the global behavior? Is it possible for TIT FOR TAT to govern the cooperative interactions of individuals in a population? The goal is to identify those strategies that are collectively stable: those strategies that are the only ones that the entire population can maintain in the long run in the face of any possible mutant strategy. Axelrod confirms that the strategy that always defects (ALL D) is collectively stable, and that no strategy that ever cooperates can invade a population using ALL D. This result, however, applies to individual mutants; consider instead what happens when a small group of TIT FOR TAT invades a population of ALL D. In this arrangement, if the individuals in the TIT FOR TAT group interact enough, they will manage a higher average “pay out” than the ALL D will generate among themselves. And so TIT FOR TAT not only forms the basis of cooperative behavior, it appears to be the target strategy of any evolutionary process with the reward structure of the prisoner's dilemma.
This observation leads to an important conclusion of this work: Mutual cooperation can emerge in a world of egoists without central control within a cluster of individuals who rely on reciprocity. This has decisive implications for biological evolution, because it underscores the importance of reciprocity based generally on symbiosis rather than kinship or true altruism. Relatedness is not necessary for the emergence of cooperation – what matters is the probability that two individuals will meet again in the future, and that they know it. It’s an exciting validation of this proposal that there are many examples in nature of symbiotic relationships in which the individuals have developed the ability to recognize one another. This, to me, is why Axelrod’s work is so noteworthy and intriguing: using a simple, theoretical device he is able to develop a predictive model of cooperative behavior in complex, biological systems. There are limitations, to be sure, but the method appears to successfully resolve the broad characteristics of evolved cooperation.
Axelrod begins by examining the problem from the standpoint of game theory. Specifically, he considers how cooperation might emerge in the course of an iterated prisoner’s dilemma. The key here is that the game is iterated – that is, the players meet again and again. This means that choices not only determine the outcome of the present move, but can also influence the later choices of the players. So, for example, it does not necessarily pay to defect like it would in a single round match. Axelrod’s approach was to solicit strategies from colleagues and professionals across a range of academic fields, play them against each other, and examine the characteristics of those that performed best.
While continuing interaction between two players is necessary for cooperation to emerge, it is not sufficient. Axelrod identifies four properties that tend to make a strategy successful: it should be nice (it should never be the first to defect), retaliatory (it should defect when defected against), forgiving (it should cooperate when cooperation is sought), and have clear behavior so that the other player can recognize the strategy and adapt to it. One entry in the prisoner's dilemma "tournament" possessed all of these qualities and it proved to be the most successful strategy overall. Called TIT FOR TAT, the strategy cooperates until defected against, after which it defects until it is cooperated with again.
Axelrod’s use of the prisoner’s dilemma is beautiful in its simplicity and power – when filtered through the classic game-theoretic workhorse, of the wide range of possible strategies, successful schemes are found to have a small number of simple characteristics in common.
Armed with the results from these initial game-theoretic considerations, Axelrod turns to the emergence of cooperation in biology, drawing on the seminal work of biologist W. D. Hamilton. Of particular interest is the question of how certain modes of cooperation evolve within a population of individuals, and given a prevailing strategy for dealing with conflict, is it possible for alternative strategies to “invade” the population and shift the global behavior? Is it possible for TIT FOR TAT to govern the cooperative interactions of individuals in a population? The goal is to identify those strategies that are collectively stable: those strategies that are the only ones that the entire population can maintain in the long run in the face of any possible mutant strategy. Axelrod confirms that the strategy that always defects (ALL D) is collectively stable, and that no strategy that ever cooperates can invade a population using ALL D. This result, however, applies to individual mutants; consider instead what happens when a small group of TIT FOR TAT invades a population of ALL D. In this arrangement, if the individuals in the TIT FOR TAT group interact enough, they will manage a higher average “pay out” than the ALL D will generate among themselves. And so TIT FOR TAT not only forms the basis of cooperative behavior, it appears to be the target strategy of any evolutionary process with the reward structure of the prisoner's dilemma.
This observation leads to an important conclusion of this work: Mutual cooperation can emerge in a world of egoists without central control within a cluster of individuals who rely on reciprocity. This has decisive implications for biological evolution, because it underscores the importance of reciprocity based generally on symbiosis rather than kinship or true altruism. Relatedness is not necessary for the emergence of cooperation – what matters is the probability that two individuals will meet again in the future, and that they know it. It’s an exciting validation of this proposal that there are many examples in nature of symbiotic relationships in which the individuals have developed the ability to recognize one another. This, to me, is why Axelrod’s work is so noteworthy and intriguing: using a simple, theoretical device he is able to develop a predictive model of cooperative behavior in complex, biological systems. There are limitations, to be sure, but the method appears to successfully resolve the broad characteristics of evolved cooperation.
July 22, 2018
This book is often touted as one of the major texts in international relations. It has applicability everywhere, from one's personal/professional dealings to US' foreign relations with Kim and Putin. Its central idea is that the Tit-for-Tat strategy, or initial cooperation followed by penalizing an opponent's defection with defection, is the ideal strategy towards any partner we engage in repeated interactions.
Tit-for-Tat is nice (does not defect first), provocable, forgiving, and consistent. It is robust even when faced with invasive attempts of other strategies, such as aggressive defection. This book devotes two chapters of case studies applying Tit-for-Tat in World War I trench warfare and in evolutionary biology. It also contains advice about how to practice Tit-for-Tat:
1) don't be envious
2) don't be first to defect
3) reciprocate both cooperation and defection
iv) don't be too clever
We are also advised to adjust to Tit-for-2-Tat when a more forgiving stance is called for in a particularly tense political environment.
Tit-for-Tat is nice (does not defect first), provocable, forgiving, and consistent. It is robust even when faced with invasive attempts of other strategies, such as aggressive defection. This book devotes two chapters of case studies applying Tit-for-Tat in World War I trench warfare and in evolutionary biology. It also contains advice about how to practice Tit-for-Tat:
1) don't be envious
2) don't be first to defect
3) reciprocate both cooperation and defection
iv) don't be too clever
We are also advised to adjust to Tit-for-2-Tat when a more forgiving stance is called for in a particularly tense political environment.
August 30, 2017
This book contained fascinating subject matter which was unfortunately greatly diminished by lackluster writing and presentation, and a significant lack of editing. I love math, and for a book to make math seem dull is kind of criminal. Also, there was way too much repetition. It was repetitive. And redundant. And, believe it or not, repetitive.
To sum up the points of interest, the most successful tactics to use in an iterated Prisoner’s Dilemma-type situation (and these situations are truly abundant in life) are: 1) avoidance of unnecessary conflict (don’t be a dick), 2) provocability in the face of an uncalled for defection (don’t be a doormat), 3) forgiveness after responding to a provocation (alas! no Sicilian-style blood feuds), and 4) clarity of behavior so that the other player can adapt to your pattern of action (it seldom pays to be inscrutable or erratic).
Also, envy is self-destructive, and it’s best not to shit where you eat.
To sum up the points of interest, the most successful tactics to use in an iterated Prisoner’s Dilemma-type situation (and these situations are truly abundant in life) are: 1) avoidance of unnecessary conflict (don’t be a dick), 2) provocability in the face of an uncalled for defection (don’t be a doormat), 3) forgiveness after responding to a provocation (alas! no Sicilian-style blood feuds), and 4) clarity of behavior so that the other player can adapt to your pattern of action (it seldom pays to be inscrutable or erratic).
Also, envy is self-destructive, and it’s best not to shit where you eat.
April 14, 2019
This is a very good read, right from the start. But the best part is that as you reach the final chapters, you see it's applications right around you. There are some very powerful ideas in there.
What will perhaps stay with me for a long time, is the strength deriving from having a reputation as a bully. If you're willing to pay the costs needed to establish your reputation, the benefits might far exceed them. I see the sense in US engaging in the occasional conflict, despite the immediate costs it faces, or big companies severely undercutting new competitors.
What more, it's also just as imporant to respond to deceptions quickly. Not something I do, thinking that it's best for me to do what helps me, not what hurts others. But if you get the reputation of being a pushover, there will be consequences. You need to retaliate, even if that hurts you in the short term.
I'll definitely go back and reread the final chapters someday.
What will perhaps stay with me for a long time, is the strength deriving from having a reputation as a bully. If you're willing to pay the costs needed to establish your reputation, the benefits might far exceed them. I see the sense in US engaging in the occasional conflict, despite the immediate costs it faces, or big companies severely undercutting new competitors.
What more, it's also just as imporant to respond to deceptions quickly. Not something I do, thinking that it's best for me to do what helps me, not what hurts others. But if you get the reputation of being a pushover, there will be consequences. You need to retaliate, even if that hurts you in the short term.
I'll definitely go back and reread the final chapters someday.
November 18, 2017
Although this book was written over 30 years ago it has a striking relevancy today as the social sciences increasingly look towards ecological and evolutionary theories to help explain social phenomena. I thoroughly enjoyed the extended discussion around an relatively simple game (the prisoner dilemma) that can characterise many social and commercial interactions.
Readers who are interested in experimental economics or complexity theory can draw out many parallels in this work with many of the modern stream of research which highlight just how progressive Alexrod was with his research in the early 1980s
Readers who are interested in experimental economics or complexity theory can draw out many parallels in this work with many of the modern stream of research which highlight just how progressive Alexrod was with his research in the early 1980s
December 26, 2013
Short book full of a big idea - how cooperation emerges. Axelrod describes an experiment where players develop strategies that compete against each other in an iterated game of Prisoner's Dilemma to see which strategy fares best - cooperation, defection, punishment, or some combination thereof. The reason I gave the book 5-stars is that it stimulated my mind to ponder the implications and ask a host of what-if questions.
February 15, 2016
Probably one of the more interesting books I have read. It may not be for everybody, but it really helped me to have a more intuitive understanding of how societies and morality form, and how agents (people) make decisions when in a group context. After reading this, I look at almost all societal problems a little bit differently. It is Game Theory applied to society, and the conclusions are fascinating.
November 30, 2017
I read this for my World Politics class that is heavily focused on International Relations theory. This class had a section on game theory and bargaining models and this book has definitely influenced the way I process relationships.
September 2, 2017
Loved it. A simple model, that explains a lot of cooperation phenomenons from real world.
November 7, 2018
Good book to get into behavioral studies concerning game theory
January 13, 2019
A foundational text in game theory. A great start, and not overly technical, although there is sufficient technical details there for those who enjoy them.
February 14, 2019
Read this book, before you get into negotiations of any kind.
February 21, 2019
Best systems/game theory book besides "Thinking in Systems".
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