The Evolution of Cooperation

This book has information for military theorists, biologists exploring gene regulation, antitrust policy-makers, and Miss Manners. It is a wonderfully clear explanation of how almost any two entities, interacting over time, develop a mutualism more profitable than greed. The experimental support for these claims comes from a series of contests. Dozens of authors provided computer programs to play in the Iterated Prisoner's Dilemma - a simple model, but one that describes a surprising number of real-world phenomena. Most importantly, it's a testable model. It almost puts a common aspect of social interaction into a test tube. What came out of that test tube was startling in its clarity and simplicity.The book is very readable. Axelrod segregates the mathematical and non-mathematical discussions with some care. Math-free readers see the whole set of experiments and conclusions, clearly explained, and need to skip only a few paragraphs during the main discussion. The last few chapters reward math-positive readers with additional precision and rigor. Even then, the math is accessible to someone with good high-school algebra skills.Axelrod's discussion truly timeless, except for references to the Cold War as current events. I can accept that. Even though that un-war is mostly over, it's a critical part of modern history and it still informs current policy. Any insight into that madness helps, and Axelrod is very helpful.This book stands above any one category. It's one of very few that I recommend to the bookshelves of every educated person.

If you read this book as long ago as I did, you probably first heard about it from Douglas Hofstadter's "Metamagical Themas" column in _Scientific American_, or the book in which his columns were collected. (If you're just now being introduced to this book, check out Hofstadter's too; his discussion of it is very helpful and insightful.) What Robert Axelrod describes in this book is a novel round-robin tournament (actually two such tournaments) in which various game-theoretic strategies were pitted against one another in the game known as the Iterated Prisoner's Dilemma. Each strategy was scored, not according to how many times it "beat" its "opponent," but according to how many points it accumulated for itself. The surprising result: a strategy dubbed TIT FOR TAT, submitted by Anatol Rapaport, cleaned everybody's clocks in both tournaments. Why was this surprising? First, because TIT FOR TAT was such a simple strategy. It didn't try to figure out what its "opponent" was going to do, or even keep much track of what its "opponent" had _already_ done. All it did was cooperate on the first move, and thereafter do whatever its "opponent" had done on the previous move. And second, because this strategy can _never_ do better than its "opponent" in any single game; the best result it could achieve, in terms of comparison with the other player, is a tie. So it was odd that such a simple strategy, one that went up against all sorts of sophisticated strategies that spent a lot of time trying to dope out what their "opponents" were up to, should do so much better than all the "clever" strategies. And it was also odd that a strategy that could never, ever "beat" its "opponent" should nevertheless do so much better _overall_ than any other strategy. As Axelrod is careful to point out, this isn't always true; how well TIT FOR TAT does depends on the population with which it's surrounded, and in fact it wouldn't have won even _these_ tournaments if certain other strategies had participated. But TIT FOR TAT is surprisingly robust, and its success does offer some tentative political lessons. Axelrod spells them out, in the form of principles like "Be nice and forgiving" -- which means: never be the first to defect; be quick to forget what your "opponent" has done in the past. And in a follow-up computer simulation, he shows that it's possible -- under some conditions -- for a little cadre of "cooperators" to increase their numbers and "take over" a population that practices other strategies. Axelrod's research was and is important for several reasons, one of which has to do with evolutionary theory: it shows that, under the right conditions, natural selection can tend to generate cooperation rather than competition, even among actors who act solely out of self-interest. Another has to do with the spontaneous growth of cooperative behavior in predominantly competitive or hostile environments (Axelrod's examples include holiday cease-fires in the trenches dur

In 20 to 50 years people will look back on the experiment described in this book as one of the very important events at the end of the 20th century. There is a section of the book that nearly forces you to abandon it, the mathematical description of the famous prisoners dilema game. But if you get past that point , it just gets more fascinating the more you read it and think about the consequences. Short descriptions of this experiment will appear in a lot of good books, but it is nice to get the complete description of the experiment, along with the author's projections of its implications in such a short wonderful book.

Sometimes, the individual benefit seems to conflict with the benefit of the community as whole, even though the community includes this very individuum. One such example has been formulated as the Prisonner's Dilemma: two suspects, A and B, are arrested, and kept separated so that they cannot communicate. If they continue to cooperate, they will be both sentenced to one year. However, if suspect A cooperates, but suspect B defects, A is going to be sentenced to five years, and suspect B will be released. Vice versa, if B cooperates and A defects, A will be released and B sentenced to five years. Finally, if both defect, they will both be sentenced to three years each.It is clear that the best solution for both of them is cooperation. On the other hand, each individual is also tempted to maximize his own individual benefit. And each of them benefits most if he decides to defect, which in turn brings the worst possible outcome for both (six years total). So one-shot Prisonner's Dilemma rarely leads to cooperation. Now, what if the very two chaps are later arrested again? Will they cooperate when given another chance? Or if they know they will face the same situation every five years? Professor Axelrod tested the iterated Prisonner's Dilemma with computer programs, and investigated under which circumstances cooperation can emerge.The book is nicely scattered with fragments of game theory and examples from world politics. All in all, as Richard Dawkins has commented in the foreword to its British edition, in breathes with optimism, and is a delight to read. Still, it has one problem, and actually shares it with Dawkins: the book reaches its climax right at the beginning. The book starts with a strong and very convincing idea, but later fails to keep the same pace of dynamic. The idea is splendid, but the structure of the book could be enhanced.

This book is a must-read not only for students (broadly defined) of the social sciences, but also for politicians and bureaucrats, especially those in charge of military and foreign affairs. Axelrod's book is a tour-de-force in multi-method approaches. Although the author is a trifle repetitive and occasionally laborious, I think the profound content of the book far outweighs the minor inadequacies of its form. At the risk of sounding like a logical positivist, I would venture to say that Axelrod's approach offers hope for a bottom-up construction of cooperation in an uncertain world without a central authority.