Here are a few examples: Romans suppressing provincial rebellions; Mongols razing cities that resist their conquest; free companies of demobilized soldiers plundering and raping; colonial settlers expelling or massacring indigenous peoples; gangsters whacking a rival, an informant, or an uncooperative official; rulers assassinating a political opponent or vice versa; governments jailing or executing dissidents; warring nations bombing enemy cities; hoodlums injuring a victim who resists a robbery or carjacking; criminals killing an eyewitness to a crime; mothers smothering a newborn they feel they cannot raise. Defensive and preemptive violence—doing it to them before they do it to you—is also a form of instrumental violence.

  Predatory violence may be the most extraordinary and perplexing phenomenon in the human moral landscape precisely because it is so mundane and explicable. We read of an atrocity—say, rebel soldiers encamped on a rooftop in Uganda who passed the time by kidnapping women, tying them up, raping them, and throwing them to their deaths—shake our heads, and ask, “How could people do these things?”79 We refuse to accept obvious answers, like boredom, lust, or sport, because the suffering of the victim is so obscenely disproportionate to the benefit to the perpetrator. We take the victim’s point of view and advert to a conception of pure evil. Yet to understand these outrages, we might be better off asking not why they happen but why they don’t happen more often.

  With the possible exception of Jain priests, all of us engage in predatory violence, if only against insects. In most cases the temptation to prey on humans is inhibited by emotional and cognitive restraints, but in a minority of individuals these restraints are absent. Psychopaths make up 1 to 3 percent of the male population, depending on whether one uses the broad definition of antisocial personality disorder, which embraces many kinds of callous troublemakers, or a narrower definition that picks out the more cunning manipulators.80 Psychopaths are liars and bullies from the time they are children, show no capacity for sympathy or remorse, make up 20 to 30 percent of violent criminals, and commit half the serious crimes.81 They also perpetrate nonviolent crimes like bilking elderly couples out of their life savings and running a business with ruthless disregard for the welfare of the workforce or stakeholders. As we saw, the regions of the brain that handle social emotions, especially the amygdala and orbital cortex, are relatively shrunken or unresponsive in psychopaths, though they may show no other signs of pathology.82 In some people, signs of psychopathy develop after damage to these regions from disease or an accident, but the condition is also partly heritable. Psychopathy may have evolved as a minority strategy that exploits a large population of trusting cooperators.83 Though no society can stock its militias and armies exclusively with psychopaths, such men are bound to be disproportionately attracted to these adventures, with their prospect of plunder and rape. As we saw in chapter 6, genocides and civil wars often involve a division of labor between the ideologues or warlords who run them and the shock troops, including some number of psychopaths, who are happy to carry them out.84

  The psychology of predatory violence consists in the human capacity for means-end reasoning and the fact that our faculties of moral restraint do not kick in automatically in our dealings with every living thing. But there are two psychological twists in the way that predatory violence is carried out.

  Though predatory violence is purely practical, the human mind does not stick to abstract reasoning for long. It tends to backslide into evolutionarily prepared and emotionally charged categories.85 As soon as the objects being preyed upon take protective measures in response, emotions are likely to run high. The human prey may hide and regroup, or they may fight back, perhaps even threatening to destroy the predator preemptively, a kind of instrumental violence of their own that gives rise to a security dilemma or Hobbesian trap. In these cases the predator’s state of mind may shift from dispassionate means-ends analysis to disgust, hatred, and anger.86 As we have seen, perpetrators commonly analogize their victims to vermin and treat them with moralized disgust. Or they may see them as existential threats and treat them with hatred, the emotion that, as Aristotle noted, consists of a desire not to punish an adversary but to end its existence. When extermination is not feasible and perpetrators have to continue to deal with their victims, either directly or with the participation of third parties, they may treat them with anger. The predators may respond to the defensive reprisals of their prey as if they were the ones under attack, and experience a moralized wrath and a thirst for revenge. Thanks to the Moralization Gap, they will minimize their own first strike as necessary and trivial while magnifying the reprisal as unprovoked and devastating. Each side will count the wrongs differently—the perpetrator tallying an even number of strikes and the victim an odd number—and the difference in arithmetic can stoke a spiral of revenge, a dynamic we will explore in a later section.

  There is a second way self-serving biases can fan a small flame of predatory violence into an inferno. People exaggerate not just their moral rectitude but their power and prospects, a subtype of self-serving bias called positive illusions. 87 Hundreds of studies have shown that people overrate their health, leadership ability, intelligence, professional competence, sporting prowess, and managerial skills. People also hold the nonsensical belief that they are inherently lucky. Most people think they are more likely than the average person to attain a good first job, to have gifted children, and to live to a ripe old age. They also think that they are less likely than the average person to be the victim of an accident, crime, disease, depression, unwanted pregnancy, or earthquake.

  Why should people be so deluded? Positive illusions make people happier, more confident, and mentally healthier, but that cannot be the explanation for why they exist, because it only begs the question of why our brains should be designed so that only unrealistic assessments make us happy and confident, as opposed to calibrating our contentment against reality. The most plausible explanation is that positive illusions are a bargaining tactic, a credible bluff. In recruiting an ally to support you in a risky venture, in bargaining for the best deal, or in intimidating an adversary into backing down, you stand to gain if you credibly exaggerate your strengths. Believing your own exaggeration is better than cynically lying about it, because the arms race between lying and lie detection has equipped your audience with the means of seeing through barefaced lies.88 As long as your exaggerations are not laughable, your audience cannot afford to ignore your self-assessment altogether, because you have more information about yourself than anyone else does, and you have a built-in incentive not to distort your assessment too much or you would constantly blunder into disasters. It would be better for the species if no one exaggerated, but our brains were not selected for the benefit of the species, and no individual can afford to be the only honest one in a community of selfenhancers. 89

  Overconfidence makes the tragedy of predation even worse. If people were completely rational, they would launch an act of predatory aggression only if they were likely to succeed and only if the spoils of the success exceeded the losses they would incur in the fighting. By the same token, the weaker party should concede as soon as the outcome was a foregone conclusion. A world with rational actors might see plenty of exploitation, but it should not see many fights or wars. Violence would come about only if the two parties were so closely matched that a fight was the only way to determine who was stronger.

  But in a world with positive illusions, an aggressor may be emboldened to attack, and a defender emboldened to resist, well out of proportion to their odds of success. As Winston Churchill noted, “Always remember, however sure you are that you can easily win, that there would not be a war if the other man did not think he also had a chance.”90 The result can be wars of attrition (in both the game-theoretic and military sense), which, as we saw in chapter 5, are among the most destructive events in history, plumping out the tail of high-magnitude wars in the power-law distribution of deadly quarrels.

  Military historians have long not
ed that leaders make decisions in war that are reckless to the point of delusion.91 The invasions of Russia by Napoleon and, more than a century later, by Hitler are infamous examples. Over the past five centuries, countries that initiated wars have ended up losing them between a quarter and a half of the time, and when they won the victories were often Pyrrhic.92 Richard Wrangham, inspired by Barbara Tuchman’s The March of Folly: From Troy to Vietnam and by Robert Trivers’s theory of self-deception, suggested that military incompetence is often a matter not of insufficient data or mistakes in strategy but of overconfidence.93 Leaders overestimate their prospects of winning. Their bravado may rally the troops and intimidate weaker adversaries, but also may put them on a collision course with an enemy who is not as weak as they think and who may be under the spell of an overconfidence of its own.

  The political scientist Dominic Johnson, working with Wrangham and others, conducted an experiment to test the idea that mutual overconfidence could lead to war.94 They ran a moderately complicated war game in which pairs of participants pretended to be national leaders who had opportunities to negotiate with, threaten, or mount a costly attack on each other in competition for diamonds in a disputed border region. The winner of the contest was the player who had more money, if their nation survived at all, at the end of several rounds of play. The players interacted with each other by computer and could not see each other, so the men didn’t know whether they were playing with another man or with a woman, and vice versa. Before they began, participants were asked to predict how well they would do relative to everyone else playing the game. The experimenters got a nice Lake Wobegon Effect: a majority thought they would do better than average. Now, in any Lake Wobegon Effect, it’s possible that not many people really are self-deceived. Suppose 70 percent of people say they are better than average. Since half of any population really is above average, perhaps only 20 percent think too well of themselves. That was not the case in the war game. The more confident a player was, the worse he or she did. Confident players launched more unprovoked attacks, especially when playing each other, which triggered mutually destructive retaliation in subsequent rounds. It will come as no surprise to women that the overconfident and mutually destructive pairs of players were almost exclusively men.

  To evaluate the overconfidence theory in the real world, it’s not enough to notice in hindsight that certain military leaders proved to be mistaken. It has to be shown that at the time of making a fateful decision, a leader had access to information that would have convinced a disinterested party that the venture would probably fail.

  In Overconfidence and War: The Havoc and Glory of Positive Illusions, Johnson vindicated Wrangham’s hypothesis by looking at the predictions made by leaders on the verge of war and showing that they were unrealistically optimistic and contradicted by information available to them at the time. In the weeks preceding World War I, for example, the leaders of England, France, and Russia on one side and of Germany, Austria-Hungary, and the Ottoman Empire on the other all predicted that the war would be a rout and their victorious troops would be home by Christmas. Ecstatic crowds of young men on both sides poured out of their homes to enlist, not because they were altruists eager to die for their country but because they didn’t think they were going to die. They couldn’t all be right, and they weren’t. In Vietnam, three American administrations escalated the war despite ample intelligence telling them that victory at an acceptable cost was unlikely.

  Destructive wars of attrition, Johnson points out, needn’t require that both sides be certain or even highly confident of prevailing. All it takes is that the subjective probabilities of the adversaries sum to a value greater than one. In modern conflicts, he notes, where the fog of war is particularly thick and the leadership removed from the facts on the ground, overconfidence can survive longer than it would have in the small-scale battles in which our positive illusions evolved. Another modern danger is that the leadership of nations is likely to go to men who are at the right tail of the distribution of confidence, well into the region of overconfidence.

  Johnson expected that wars stoked by overconfidence should be less common in democracies, where the flow of information is more likely to expose the illusions of leaders to cold splashes of reality. But he found that it was the flow of information itself, rather than just the existence of a democratic system, that made the difference. Johnson published his book in 2004, and the choice of an image for the cover was a no-brainer: the famous 2003 photograph of a flight-suited George W. Bush on the deck of an aircraft carrier festooned with the banner “Mission Accomplished.” Overconfidence did not undermine the conduct of the Iraq War itself (other than for Saddam Hussein, of course), but it was fatal to the postwar goal of bringing stable democracy to Iraq, which the Bush administration catastrophically failed to plan for. The political scientist Karen Alter conducted an analysis before the war broke out showing that the Bush administration was unusually closed in its decision-making process.95 In a textbook illustration of the phenomenon of groupthink, the prewar policy team believed in its own infallibility and virtue, shut out contradictory assessments, enforced consensus, and self-censored private doubts.96

  Just before the Iraq War, Defense Secretary Donald Rumsfeld observed,

  There are known knowns; there are things we know we know. We also know there are known unknowns; that is to say we know there are some things we do not know. But there are also unknown unknowns—the ones we don’t know we don’t know.

  Johnson, following a remark by the philosopher Slavoj Žižek, notes that Rumsfeld omitted a crucial fourth category, the unknown knowns—things that are known, or at least could be known, but are ignored or suppressed. It was the unknown knowns that allowed a moderate amount of instrumental violence (a few weeks of shock and awe) to unleash an open-ended exchange of every other kind of violence.

  DOMINANCE

  The colorful idioms chest-thumping, having a chip on his shoulder, drawing a line in the sand, throwing down the gauntlet, and pissing contest all denote an action that is inherently meaningless but provokes a contest for dominance. That is a sign that we are dealing with a category that is very different from predatory, practical, or instrumental violence. Even though nothing tangible is at stake in contests for dominance, they are among the deadliest forms of human quarrel. At one end of the magnitude scale, we have seen that many wars in the Ages of Dynasties, Sovereignty, and Nationalism were fought over nebulous claims to national preeminence, including World War I. At the other end of the scale, the single largest motive for homicide is “altercations of relatively trivial origin; insult, curse, jostling, etc.”

  In their book on homicide, Martin Daly and Margo Wilson advise that “the participants in these ‘trivial altercations’ behave as if a great deal more is at issue than small change or access to a pool table, and their evaluations of what is at stake deserve our respectful consideration.”97 Contests of dominance are not as ridiculous as they seem. In any zone of anarchy, an agent can protect its interests only by cultivating a reputation for a willingness and an ability to defend itself against depredations. Though this mettle can be demonstrated in retaliation after the fact, it’s better to flaunt it proactively, before any damage is done. To prove that one’s implicit threats are not hot air, it may be necessary to seek theaters in which one’s resolve and retaliatory capacity can be displayed: a way to broadcast the message “Don’t fuck with me.” Everyone has an interest in knowing the relative fighting abilities of the agents in their midst, because all parties have an interest in preempting any fight whose outcome is a foregone conclusion and that would needlessly bloody both fighters if carried out.98 When the relative prowesses of the members of a community are stable and widely known, we call it a dominance hierarchy. Dominance hierarchies are based on more than brute strength. Since not even the baddest primate can win a fight of one against three, dominance depends on the ability to recruit allies—who, in turn, don’t choose their teammates at random but joi
n up with the stronger and shrewder ones.99

  The commodity that is immediately at stake in contests of dominance is information, and that feature differentiates dominance from predation in several ways. One is that while contests of dominance can escalate into lethal clashes, especially when the contestants are closely matched and intoxicated with positive illusions, most of the time (in humans and animals alike) they are settled with displays. The antagonists flaunt their strength, brandish their weapons, and play games of brinkmanship; the contest ends when one side backs down.100 With predation, in contrast, the only point is to obtain an object of desire.

  Another implication of the informational stakes in contests of dominance is that the violence is interwoven with exchanges of data. Reputation is a social construction that is built on what logicians call common knowledge. To avert a fight, a pair of rivals must not only know who is stronger, but each must know that the other knows, and must know that the other knows that he knows, and so on.101 Common knowledge may be undermined by a contrary opinion, and so contests of dominance are fought in arenas of public information. They may be sparked by an insult, particularly in cultures of honor, and in those that sanction formal dueling. The insult is treated like a physical injury or theft, and it sets off an urge for violent revenge (which can make the psychology of dominance blend into the psychology of revenge, discussed in the next section). Studies of American street violence have found that the young men who endorse a code of honor are the ones most likely to commit an act of serious violence in the following year.102 They also have found that the presence of an audience doubles the likelihood that an argument between two men will escalate to violence.103

  When dominance is reckoned within a closed group, it is a zero-sum game: if someone’s rank goes up, another’s has to go down. Dominance tends to erupt in violence within small groups like gangs and isolated workplaces, where a person’s rank within the clique determines the entirety of his social worth. If people belong to many groups and can switch in and out of them, they are more likely to find one in which they are esteemed, and an insult or slight is less consequential.104