the results of international surveys. A major predictor of excess revenge turned out to be civic norms: a measure of the degree to which people think it is all right to cheat on their income taxes, claim government benefits to which they are not entitled, and dodge fare-collectors on the subway. (Social scientists believe that civic norms make up a large part of the social capital of a country, which is more important to its prosperity than its physical resources.) Where might the civic norms themselves have come from? The World Bank assigns countries a score called the Rule of Law, which reflects how well private contracts can be enforced in courts, whether the legal system is perceived as being fair, the importance of the black market and organized crime, the quality of the police, and the likelihood of crime and violence. In the experiment, the Rule of Law of a country significantly predicted the degree to which its citizens indulged in antisocial revenge: the people in countries with an iffy Rule of Law were more destructively vengeful. With the usual spaghetti of variables, it’s impossible to be certain what caused what, but the results are consistent with the idea that the disinterested justice of a decent Leviathan induces citizens to curb their impulse for revenge before it spirals into a destructive cycle.
Revenge, for all its tendency to escalate, must come with a dimmer switch. If it didn’t, the Moralization Gap would inflate every affront into an escalating feud, like the experimental subjects who mashed down on each other’s fingers harder and harder with every round. Not only does revenge not always escalate, especially in civil societies with the rule of law, but we shouldn’t expect it to. The models of the evolution of cooperation showed that the most successful agents dial back their tit-for-tatting with contrition and forgiveness, especially when trapped in the same boat with other agents.
In Beyond Revenge: The Evolution of the Forgiveness Instinct, the psychologist Michael McCullough shows that we do have this dimmer switch for revenge.209 As we have seen, several species of primate can kiss and make up after a fight, at least if their interests are bound by kinship, shared goals, or common enemies. 210 McCullough shows that the human forgiveness instinct is activated under similar circumstances.
The desire for revenge is most easily modulated when the perpetrator falls within our natural circle of empathy. We are apt to forgive our kin and close friends for trespasses that would be unforgivable in others. And when our circle of empathy expands (a process we will examine in the next chapter), our circle of forgivability expands with it.
A second circumstance that cranks down revenge is a relationship with the perpetrator that is too valuable to sever. We may not like them, but we’re stuck with them, so we had better learn to live with them. During the presidential primary season, rivals for a party’s nomination can spend months slinging each other with mud or worse, and their body language during televised debates makes it clear that they can’t stand each other. But when the winner is decided, they bite their lips, swallow their pride, and unite against their common adversary in the other party. In many cases the winner even invites the loser onto the ticket or into the cabinet. The power of a shared goal to induce erstwhile enemies to reconcile was dramatically demonstrated in a famous 1950s experiment in which boys at a summer camp called Robbers Cave were divided into teams and on their own initiative waged war on each other for weeks, with raids and retaliations and dangerous weapons like rocks in socks.211 But when the psychologists arranged some “accidents” that left the boys no choice but to work together to restore the camp’s water supply and to pull a bus out of the muck, they fell into a truce, overcame their enmity, and even made some friendships across team lines.
The third modulator of revenge kicks in when we are assured that the perpetrator has become harmless. For all the warmth and fuzziness of forgiveness, you can’t afford to disarm if the person who harmed you is likely to do it again. So if a harm-doer wants to avoid your wrath and get back on your good side, he has to persuade you that he no longer harbors any motive to harm you. He may start out by claiming that his harm was an unfortunate result of a unique set of circumstances