Scientifically oriented researchers on violence chant a different mantra: “Violence is a public health problem.” According to the National Institute of Mental Health, “Violent behavior can best be understood—and prevented—if it is attacked as if it were a contagious disease that flourishes in vulnerable individuals and resource-poor neighborhoods.” The public health theory has been echoed by many professional organizations, such as the American Psychological Society and the Centers for Disease Control, and by political figures as diverse as the surgeon general in the Clinton administration and the Republican senator Arlen Specter.27 The public health approach tries to identify “risk factors” that are more common in poor neighborhoods than affluent ones. They include neglect and abuse in childhood, harsh and inconsistent discipline, divorce, malnutrition, lead poisoning, head injuries, untreated attention deficit hyperactivity disorder, and the use of alcohol and crack cocaine during pregnancy.
Researchers in this tradition are proud that their approach is both “biological”—they measure bodily fluids and take pictures of the brain—and “cultural”—they look for environmental causes of the brain conditions that might be ameliorated by the equivalent of public health measures. Unfortunately, there is a rather glaring flaw in the whole analogy. A good definition of a disease or disorder is that it consists of suffering experienced by an individual because of a malfunction of a mechanism in the individual’s body.28 But as a writer for Science recently pointed out, “Unlike most diseases, it’s usually not the perpetrator who defines aggression as a problem; it’s the environment. Violent people may feel they are functioning normally, and some may even enjoy their occasional outbursts and resist treatment.”29 Other than the truism that violence is more common in some people and places than others, the public health theory has little to recommend it. As we shall see, violence is not a disease in anything like the medical sense.
PURE ENVIRONMENTAL THEORIES of violence remain an article of faith because they embody the Blank Slate and the Noble Savage. Violence, according to these theories, isn’t a natural strategy in the human repertoire; it’s learned behavior, or poisoning by a toxic substance, or the symptom of an infectious illness. In earlier chapters we saw the moral appeal of such doctrines: to differentiate the doctrine-holders from jingoists of earlier periods and ruffians of different classes; to reassure audiences that they do not think violence is “natural” in the sense of “good”; to express an optimism that violence can be eliminated, particularly by benign social programs rather than punitive deterrence; to stay miles away from the radioactive position that some individuals, classes, or races are innately more violent than others.
Most of all, the learned-behavior and public health theories are moral declarations, public avowals that the declarer is opposed to violence. Condemning violence is all to the good, of course, but not if it is disguised as an empirical claim about our psychological makeup. Perhaps the purest example of this wishful confusion comes from Ramsey Clark, attorney general in the Johnson administration and the author of the 1970 bestseller Crime in America. In arguing that the criminal justice system should replace punishment with rehabilitation, Clark explained:
The theory of rehabilitation is based on the belief that healthy, rational people will not injure others, that they will understand that the individual and his society are best served by conduct that does not inflict injury, and that a just society has the ability to provide health and purpose and opportunity for all its citizens. Rehabilitated, an individual will not have the capacity—cannot bring himself—to injure another or take or destroy property.30
Would that it were so! This theory is a fine example of the moralistic fallacy: it would be so nice if the idea were true that we should all believe that it is true. The problem is that it is not true. History has shown that plenty of healthy, rational people can bring themselves to injure others and destroy property because, tragically, an individual’s interests sometimes are served by hurting others (especially if criminal penalties for hurting others are eliminated, an irony that Clark seems to have missed). Conflicts of interest are inherent to the human condition, and as Martin Daly and Margo Wilson point out, “Killing one’s adversary is the ultimate conflict resolution technique.”31
Admittedly, it is easy to equate health and rationality with morality. The metaphors pervade the English language, as when we call an evildoer crazy, degenerate, depraved, deranged, mad, malignant, psycho, sick, or twisted. But the metaphors are bound to mislead us when we contemplate the causes of violence and ways to reduce it. Termites are not malfunctioning when they eat the wooden beams in houses, nor are mosquitoes when they bite a victim and spread the malaria parasite. They are doing exactly what evolution designed them to do, even if the outcome makes people suffer. For scientists to moralize about these creatures or call their behavior pathological would only send us all down blind alleys, such as a search for the “toxic” influences on these creatures or a “cure” that would restore them to health. For the same reason, human violence does not have to be a disease for it to be worth combating. If anything, it is the belief that violence is an aberration that is dangerous, because it lulls us into forgetting how easily violence may erupt in quiescent places.
The Blank Slate and the Noble Savage owe their support not just to their moral appeal but to enforcement by ideology police. The blood libel against Napoleon Chagnon for documenting warfare among the Yanomamö is the most lurid example of the punishment of heretics, but it is not the only one. In 1992 a Violence Initiative in the Alcohol, Drug Abuse, and Mental Health Administration was canceled because of false accusations that the research aimed to sedate inner-city youth and to stigmatize them as genetically prone to violence. (In fact, it advocated the public health approach.) A conference and book on the legal and moral issues surrounding the biology of violence, which was to include advocates of all viewpoints, was canceled by Bernadine Healey, director of the National Institutes of Health, who overruled a unanimous peer-review decision because of concerns “associated with the sensitivity and validity of the proposed conference.”32 The university sponsoring the conference appealed and won, but when the conference was held three years later, protesters invaded the hall and, as if to provide material for comedians, began a shoving match with the participants.33
What was everyone so sensitive about? The stated fear was that the government would define political unrest in response to inequitable social conditions as a psychiatric disease and silence the protesters by drugging them or worse. The radical psychiatrist Peter Breggin called the Violence Initiative “the most terrifying, most racist, most hideous thing imaginable” and “the kind of plan one would associate with Nazi Germany.”34 The reasons included “the medicalization of social issues, the declaration that the victim of oppression, in this case the Jew, is in fact a genetically and biologically defective person, the mobilization of the state for eugenic purposes and biological purposes, the heavy use of psychiatry in the development of social-control programs.”35 This is a fanciful, indeed paranoid, reading, but Breggin has tirelessly repeated it, especially to African American politicians and media outlets. Anyone using the words “violence” and “biology” in the same paragraph may be put under a cloud of suspicion for racism, and this has affected the intellectual climate regarding violence. No one has ever gotten into trouble for saying that violence is completely learned.
THERE ARE MANY reasons to believe that violence in humans is not literally a sickness or poisoning but part of our design. Before presenting them, let me allay two fears.
The first fear is that examining the roots of violence in human nature consists of reducing violence to the bad genes of violent individuals, with the unsavory implication that ethnic groups with higher rates of violence must have more of these genes.
There can be little doubt that some individuals are constitutionally more prone to violence than others. Take men, for starters: across cultures, men kill men twenty to forty times more ofte
n than women kill women.36 And the lion’s share of the killers are young men, between the ages of fifteen and thirty.37 Some young men, moreover, are more violent than others. According to one estimate, 7 percent of young men commit 79 percent of repeated violent offenses.38 Psychologists find that individuals prone to violence have a distinctive personality profile. They tend to be impulsive, low in intelligence, hyperactive, and attention-deficient. They are described as having an “oppositional temperament”: they are vindictive, easily angered, resistant to control, deliberately annoying, and likely to blame everything on other people.39 The most callous among them are psychopaths, people who lack a conscience, and they make up a substantial percentage of murderers.40 These traits emerge in early childhood, persist through the lifespan, and are largely heritable, though nowhere near completely so.
Sadists, hotheads, and other natural-born killers are part of the problem of violence, not just because of the harm they wreak but because of the aggressive posture they force others into for deterrence and self-defense. But my point here is that they are not the major part of the problem. Wars start and stop, crime rates yo-yo, societies go from militant to pacifist or vice versa within a generation, all without any change in the frequencies of the local genes. Though ethnic groups differ today in their average rates of violence, the differences do not call for a genetic explanation, because the rate for a group at one historical period may be matched to that of any other group at another period. Today’s docile Scandinavians descended from bloodthirsty Vikings, and Africa, wracked by war after the fall of colonialism, is much like Europe after the fall of the Roman Empire. Any ethnic group that has made it into the present probably had pugnacious ancestors in the not-too-distant past.
The second fear is that if people are endowed with violent motives, they can’t help being violent, or must be violent all the time, like the Tasmanian Devil in Looney Tunes who tears through an area leaving a swath of destruction in his wake. This fear is a reaction to archaic ideas of killer apes, a thirst for blood, a death wish, a territorial imperative, and a violent brain. In fact, if the brain is equipped with strategies for violence, they are contingent strategies, connected to complicated circuitry that computes when and where they should be deployed. Animals deploy aggression in highly selective ways, and humans, whose limbic systems are enmeshed with outsize frontal lobes, are of course even more calculating. Most people today live their adult lives without ever pressing their violence buttons.
So what is the evidence that our species may have evolved mechanisms for discretionary violence? The first thing to keep in mind is that aggression is an organized, goal-directed activity, not the kind of event that could come from a random malfunction. If your lawnmower continued to run after you released the handle and it injured your foot, you might suspect a sticky switch or other breakdown. But if the lawnmower lay in wait until you emerged from the garage and then chased you around the yard, you would have to conclude that someone had installed a chip that programmed it to do so.
The presence of deliberate chimpicide in our chimpanzee cousins raises the possibility that the forces of evolution, not just the idiosyncrasies of a particular human culture, prepared us for violence. And the ubiquity of violence in human societies throughout history and prehistory is a stronger hint that we are so prepared.
When we look at human bodies and brains, we find more direct signs of design for aggression. The larger size, strength, and upper-body mass of men is a zoological giveaway of an evolutionary history of violent male-male competition.41 Other signs include the effects of testosterone on dominance and violence (which we will encounter in the chapter on gender), the emotion of anger (complete with reflexive baring of the canine teeth and clenching of the fists), the revealingly named fight-or-flight response of the autonomic nervous system, and the fact that disruptions of inhibitory systems of the brain (by alcohol, damage to the frontal lobe or amygdala, or defective genes involved in serotonin metabolism) can lead to aggressive attacks, initiated by circuits in the limbic system.42
Boys in all cultures spontaneously engage in rough-and-tumble play, which is obviously practice for fighting. They also divide themselves into coalitions that compete aggressively (calling to mind the remark attributed to the Duke of Wellington that “the Battle of Waterloo was won upon the playing fields of Eton”).43 And children are violent well before they have been infected by war toys or cultural stereotypes. The most violent age is not adolescence but toddlerhood: in a recent large study, almost half the boys just past the age of two, and a slightly smaller percentage of the girls, engaged in hitting, biting, and kicking. As the author pointed out, “Babies do not kill each other, because we do not give them access to knives and guns. The question… we’ve been trying to answer for the past 30 years is how do children learn to aggress. [But] that’s the wrong question. The right question is how do they learn not to aggress.”44
Violence continues to preoccupy the mind throughout life. According to independent surveys in several countries by the psychologists Douglas Ken-rick and David Buss, more than 80 percent of women and 90 percent of men fantasize about killing people they don’t like, especially romantic rivals, stepparents, and people who have humiliated them in public.45 People in all cultures take pleasure in thinking about killings, if we are to judge by the popularity of murder mysteries, crime dramas, spy thrillers, Shakespearean tragedies, biblical stories, hero myths, and epic poems. (A character in Tom Stoppard’s Rosencrantz and Guildenstern Are Dead asks, “You’re familiar with the great tragedies of antiquity, are you? The great homicidal classics?”) People also enjoy watching the stylized combat we call “sports,” which are contests of aiming, chasing, or fighting, complete with victors and the vanquished. If language is a guide, many other efforts are conceptualized as forms of aggression: intellectual argument (to shoot down, defeat, or destroy an idea or its proponent), social reform (to fight crime, to combat prejudice, the War on Poverty, the War on Drugs), and medical treatment (to fight cancer, painkillers, to defeat AIDS, the War on Cancer).
In fact, the entire question of what went wrong (socially or biologically) when a person engages in violence is badly posed. Almost everyone recognizes the need for violence in defense of self, family, and innocent victims. Moral philosophers point out that there are even circumstances in which torture is justified—say, when a captured terrorist has planted a time bomb in a crowded place and refuses to say where it is. More generally, whether a violent mindset is called heroic or pathological often depends on whose ox has been gored. Freedom fighter or terrorist, Robin Hood or thief, Guardian Angel or vigilante, nobleman or warlord, martyr or kamikaze, general or gang leader—these are value judgments, not scientific classifications. I doubt that the brains or genes of most of the lauded protagonists would differ from those of their vilified counterparts.
In this way I find myself in agreement with the radical scientists who insist that we will never understand violence by looking only at the genes or brains of violent people. Violence is a social and political problem, not just a biological and psychological one. Nonetheless, the phenomena we call “social” and “political” are not external happenings that mysteriously affect human affairs like sunspots; they are shared understandings among individuals at a given time and place. So one cannot understand violence without a thorough understanding of the human mind.
In the rest of this chapter I explore the logic of violence, and why emotions and thoughts devoted to it may have evolved. This is necessary to disentangle the knot of biological and cultural causes that make violence so puzzling. It can help explain why people are prepared for violence but act on those inclinations only in particular circumstances; when violence is, at least in some sense, rational and when it is blatantly self-defeating; why violence is more prevalent in some times and places than in others, despite a lack of any genetic difference among the actors; and, ultimately, how we might reduce and prevent violence.
THE FIRST STEP in understan
ding violence is to set aside our abhorrence of it long enough to examine why it can sometimes pay off in personal or evolutionary terms. This requires one to invert the statement of the problem—not why violence occurs, but why it is avoided. Morality, after all, did not enter the universe with the Big Bang and then pervade it like background radiation. It was discovered by our ancestors after billions of years of the morally indifferent process known as natural selection.
In my view, the consequences of this background amorality were best worked out by Hobbes in Leviathan. Unfortunately, Hobbes’s pithy phrase “nasty, brutish, and short” and his image of an all-powerful leviathan keeping us from each other’s throats have led people to misunderstand his argument. Hobbes is commonly interpreted as proposing that man in a state of nature was saddled with an irrational impulse for hatred and destruction. In fact his analysis is more subtle, and perhaps even more tragic, for he showed how the dynamics of violence fall out of interactions among rational and self-interested agents. Hobbes’s analysis has been rediscovered by evolutionary biology, game theory, and social psychology, and I will use it to organize my discussion of the logic of violence before turning to the ways in which humans deploy peaceable instincts to counteract their violent ones.