Changing the game: Bob Axelrod's powerful blueprint for peace

December 18, 2012

By Erin M. Spanier

We've all heard the dictum, an eye for an eye, a tooth for a tooth. It's an ancient Mesopotamian legal tradition recorded in Hammurabi's Code and in the holy texts of many religious faiths. The concept is simple: repay insult in kind—wound for wound, stripe for stripe, even life for life.

We've also heard the counterargument—an eye for an eye makes the whole world blind. But the two are far from mutually exclusive explains Robert Axelrod in his highly acclaimed book, The Evolution of Cooperation, which outlines a powerfully effective recipe for deescalating conflict.

"I came to this project believing one should be slow to anger," wrote Axelrod in 1984, confessing to his surprise in discovering that quick, even-handed repayment of both kindnesses and insults, when combined with the qualities of absolute predictability and occasional generosity, actually set the stage for future cooperation. "It changed my worldview," he says.

When the work was first published, it changed the worldview of others, too. The Wall Street Journal wrote "copies should be marked 'urgent' and sent to our strategic arms negotiators, to all businessmen, to all lawyers and to anyone who has to deal with anyone else—which is everyone." The New York Times suggested it might be "our best hope" for extricating the world from the era's escalating arms race.

Axelrod was recognized with a MacArthur Foundation genius grant; he was inducted into the National Academy of Sciences (the youngest political scientist ever to receive that honor); and he was the first to be recognized with the Academy's award for "behavioral research relevant to the prevention of nuclear war."

Even today, twenty-eight years since his work was first published, Axelrod is a legendary figure known to anyone with a serious interest in conflict and cooperation. Michael Pan (MPP '99), deputy chief of staff for United Nations Ambassador Susan Rice, has encountered diplomats, political scientists, and policymakers all over the world who have studied Axelrod's work. Pan explains that the ideas in The Evolution of Cooperation are part of the bloodstream of international negotiations. "In high-stakes diplomacy, those principles inform the strategies you employ," he said.


Robert Axelrod

Robert Axelrod

How did Axelrod come to his discovery? What was so revolutionary about his work? And how has it impacted the work of scholars, diplomats, and corporations in the intervening years? Those are stories well worth the telling.

It all begins with Axelrod's keen interest in the nascent field of game theory, which posits that wellcrafted thought exercises, or "games," can not only offer analogies for understanding human behavior, but with rigorous testing and analysis of a variety of approaches, they can mimic, mirror, and predict it. A host of these games—stag hunt, hawk-dove, cake-cutting—had been designed, each with its own intriguing premise and application. The game that caught Axelrod's attention though, and indeed the game that intrigued most political scientists of the era, was the Prisoner's Dilemma.

If you've ever read Truman Capote's reportorial masterpiece, In Cold Blood, you can envision the separate interrogations of Perry Smith and Dick Hickock to get a sense of the premise. In spite of their elaborately plotted alibi—an alibi they had practiced ad infinitum while on the run—both Smith and Hickock were sorely tempted to rat each other out, or defect, in exchange for a lighter sentence. If one defected, but the other did not, the snitch would win the lightest sentence and the sucker the most severe. If both defected, both would earn heavy sentences—the worst overall outcome (and, in fact, the path Smith and Hickock chose to take). But if neither defected, if both stuck to the improbable story of the girls and the motel room, if they cooperated with each other rather than with the authorities, both would benefit.

Now, no one wants two cold-blooded killers to get away with anything. Axelrod certainly didn't. But two-player negotiations that reward cooperation—the premise of a Prisoner's Dilemma—occur in thousands upon thousands of real-world situations like conflict negotiations, business agreements, trade treaties, and divorce proceedings. So thought leaders the world over were spending an enormous amount of time and ink exploring theories about how to play the game to achieve the best possible outcome (by one 1975 count, some 2,000 articles had been written about the Prisoner's Dilemma). Some of the proposed approaches were nice; some were nasty; and some were strategic, attempting to get away with every possible defection.

No one, though, not Bob Axelrod, not even the theorists themselves, really knew which of these strategies was superior when the parties would interact with each other over longer periods of time, allowing them to use history to build a climate of trust and cooperation. But the general sense, evinced by Bill Hamilton, arguably the most influential evolutionary biologist since Darwin, went something like this: "surely it's proven, isn't it, that you must always defect in that game, repeated or not?" Nobel Laureate Elinor Ostrom echoed this thought. Before Axelrod's work, she wrote, "Formal theorists repeatedly demonstrated that mutual defection was the predicted outcome…there appeared to be no other solution to this depressing theoretical conclusion."

Defection, however, was not a favorable option in ongoing relationships. Among rational actors, (excluding saints, of course), each defection sows doubt, mistrust, and similar acts of defection in what can become an endless series of escalating conflicts. Having come of age during the Cuban Missile Crisis, the Cold War and its escalating arms race, and Vietnam, Axelrod hoped he might find a strategy that could avoid dangerous conflict, deescalate tensions, and Having come of age during the Cuban Missile Crisis, the Cold War and its escalating arms race, and Vietnam, Axelrod hoped he might find a strategy that could avoid dangerous conflict, deescalate tensions, and foster long-term cooperation among adversarial parties. So Axelrod invited game theorists all over the world to submit programs for a lengthy Prisoner's Dilemma tournament that would pit each strategy against itself, each against the others, and each against a random strategy that would cooperate or defect evenly, but unpredictably.

Game theorists responded with all sorts of approaches. There was Massive Retaliatory Strike, which would punish any defection relentlessly. There was Tester, which would attempt defection then back off if punished, but would defect again when least expected. There were endlessly forgiving programs. And there was one program, submitted by Anatol Rapaport, a pioneering mathematician and game theorist, dubbed simply Tit-for-Tat. This was the simplest of all programs: it cooperated on the first move, then mirrored the last move of its opponent for the remainder of the play—all 120,000 moves in Axelrod's 200-round tournament. It was also, it turns out, the clear winner of the tournament, outscoring every other strategy.

It's important to understand that Tit-for-Tat, the winning strategy in the tournament, never won a single game. "It couldn't. The best it can do is tie, or finish one point behind its opponent," explains Axelrod. It won the tournament for another reason entirely: because it elicited cooperation from its adversaries. How? In part, because it was no pushover. Punch Tit-for-Tat? It punched you back. In fact, it punched you back so reliably that you might think twice about punching it again.

Tit-for-Tat did, however, have one major drawback: it could become embroiled in conflict with confrontational programs, and those conflicts could go on and on and on.... The missing ingredient, Axelrod learned after a second tournament, was generosity. Occasional generosity, an unexpected act of kindness even in the midst of conflict, can be an effective way to rebuild an atmosphere of trust.

Axelrod's carefully constructed and analyzed tournaments, and his engaging and accessible book, The Evolution of Cooperation, put an end to the mistaken belief that defection is always the best strategy in a conflict, offering military strategists a mathematically defensible reason to moderate their response to perceived aggression.

This alone would be a monumental contribution to science and society, but as with so many of the most remarkable discoveries, Axelrod's took on new life, influencing ideas and inquiries in dozens of other fields.

Together with Bill Hamilton, Axelrod used it to explain acts of altruism among unrelated animals like vampire bats and cleaner fish and even non-sentient organisms like bacteria. Corporations have used these ideas to navigate high-stakes business negotiations. Economists have used them to determine when communities can effectively collaborate to protect rapidly declining natural resources like lobsters, salmon, and cod. Even medical researchers have been influenced by Axelrod's theories: oncologists, for example, have worked with him to develop new experimental treatments.

Google Scholar lists 22,000 books and articles that have cited The Evolution of Cooperation, including 1,000 new citations this year alone. The range is vast—from moral history to strategic alliances, from profit sharing to medicine—and the numbers have grown larger each year as the book has been translated into new languages (eleven so far, with a twelfth, Arabic, now in the works).

Interestingly, though, Axelrod himself has moved on.

For the past several years, Bob Axelrod has devoted himself to nurturing the next generation of leaders in international policy and to new avenues of inquiry. Among them, he explores the historical analogies that guide political decision-making, the sacred values that restrict negotiation, and promising new strategies for approaching intractable conflicts. Together with collaborators Scott Atran and Richard Davis, Axelrod travels to the Middle East every chance he gets to interview the leaders of nation states like Egypt, Israel, and Syria and powerful organizations like Hamas, Fatah, Salafi, and the Egyptian Muslim Brotherhood.

"Could Egypt and the United States mediate a peace process between Israel and the Palestinians today?" he asks of Egypt's new rulers, members of the Muslim Brotherhood, listening attentively to each response. After all these years, and everything he's accomplished, Axelrod is still searching for paths toward peace.

Headline Illustration: © 2012 Dean Rohrer, c/o

Below is a formatted version of this article from State & Hill, the magazine of the Ford School. View the entire Fall 2012 State & Hill here.