The biological roots of war seem to run deep. Biology can answer some of our questions about the reasons we go to war and commit acts of violence against one another. This post reviews two books that consider the effects of our biology on our apparent propensity to war. It is possible, however, that the premise that we are prone to war is mistaken, and we will consider evidence for that as well.
In Sex and War: How Biology Explains Warfare and Terrorism and Offers a Path to a Safer World, Malcolm Potts and Thomas Hayden attempt to explain the roots of modern warfare by looking at human biology. First, killing seems to have an adaptive function, meaning, in the end, that men who kill end up having more children, and thus passing on their genes. The most competitive and aggressive males tend to make the largest contribution to the human gene pool, thus reinforcing our tendencies to violence. For instance, some 8% of Central Asians can trace their genes to Genghis Khan. Because evolution favours only those who reproduce, for men “at the bottom of the social pile” it is rational to risk everything, including violent death, when the alternative is not to pass on their genes.
95% of human history has been spent living and fighting in small clans. Now we live in a modern age that does not require the same aggressive behaviour, and we benefit far more from cooperation than violent competition, but nature is slow to evolve. Culture, however, evolves quickly, and its influences on our behaviour can help us “rein in our Stone Age behaviours”, such as murder and rape. Rape is common during wartime, and logically a man’s reproductive success will increase if he kills other men and rapes women. “This does not mean that men have evolved to rape,” say Potts and Hayden, “but it does suggest that many if not all men have at least the biological potential to experience the aggression, loose emotional control and dissociation from empathy that presumably underlie the act.”
Testosterone is one factor that might account for aggression, particularly differences in aggression between men and women. Testosterone is twenty times higher in men than in women. It accounts for men’s greater muscle strength, drive for status and aggression, as well as weaker control over their impulses. Unmarried men aged 20 to 24 are three times as likely to murder someone as married men of the same age. Studies also find high levels of testosterone in men convicted for violent offenses. Testosterone increases among male soccer players before and during a game. They fall among losers, but the winners experience elevated levels sometimes for days after the match. Even the fans experience rising testosterone, as we identify so strongly with our side, even when we are not fighting. High testosterone correlates strongly with assertiveness, competitiveness and the desire to manipulate others.
Chimpanzees–but bonobos too
Potts and Hayden draw much of their writing from observations of chimpanzees. We share a common ancestor with chimpanzees from about five to seven million years ago, and according to biologists, 99.6% of our DNA. Some chimp behaviour is a mirror to our own, particularly the hunting and killing–sometimes with appalling brutality–of members of the same species. Chimpanzees jockey for influence and status, impose hierarchy and reward loyalty. They also work to establish peace after fighting. In what Potts and Hayden call “the chimpanzee equivalent of international relations” we can see a reflection of human war. Each chimpanzee troop recognises its territory and borders, which it patrols. All adult male chimps display a keenness to participate in team raids on others’ territory that could end in bloody, torturous death. They fight over territory and access to resources. As a troop’s territory grows, so too does its access to food and mates, and as such expanding territory through team aggression is a way to have more offspring that survive. Surprise attacks and the use of overwhelming force are features of chimpanzee “wars”. Such brutality in chimps, as in humans, depends on the ability to turn off empathy for the enemy. Chimps display generosity to others in their ingroup, which comprises their blood relations, and hostility to their outgroup. Humans are much the same, except that our associations need not be familial. Nationalism, or its counterparts in race, religion and other associations, creates a sense of family that we are willing to kill for.
Chimpanzees even “de-chimpanzee-ise” in the same way we dehumanise. “Indeed, it might well be impossible for an intelligent, highly social animal to kill its own kind systematically unless it evolved some sort of neural machinery to de-identify those it is about to kill.” Combine the dangers of dehumanisation with our desire to go along with our group and deference to authority, and humans can become mindless killing machines.
Douglas P. Fry, however, questions the usefulness of comparing humans with chimps. ”At best, chimpanzees provide only tangential insights about human behaviour in the evolutionary past.” The idea that chimpanzee raiding has the same root as human warfare may be to obscure the differences between the two species (they have evolved separately for millions of years, after all) and ignore humans’ similarities to bonobos, to which they are roughly equally related. “Linking humans to chimpanzees instead of to bonobos is an arbitrary decision that is begging for a convincing rationale.” Bonobos do not engage in raiding. Fry quotes Frans de Waal, who in Our Inner Ape says “I sometimes try to imagine what would have happened if we’d known the bonobo first and chimpanzee only later or not at all. The discussion about human evolution might not revolve as much around violence, warfare and male dominance, but rather around sexuality, empathy, caring, and cooperation.”
Creating the ingroup
Much of Potts and Hayden’s comparisons of humans with chimpanzees considers raids. Both humans and chimps engage in violent raids on enemy territory. War may be just an extension, an “evolution”, of team raids. Though wars can involve millions of people, fighting units (to whom loyalty is apportioned most strongly) are often small groups, like raiding parties. Fighters are the same age and condition, bonded by a sense of kinship. Raids are dangerous and depend on being able to trust every member of the team, so it is not surprising that the sense of honour is strongest among young men at the prime of their physical strength. Virtues such as loyalty, courage and camaraderie, essential to a psychological understanding of war, evolved as ways for us to protect those in our family. As Richard Dawkins explains in The Selfish Gene, because our bodies are just vehicles for our genes, we will go to great lengths, including self-sacrifice, to protect our genes. Our genes are carried by our children, grandchildren, nieces, nephews, and so on. Therefore, we will sacrifice to save them. We can have the same feelings toward anyone we consider equivalent to kin: our friends, nation or team.
This transfer of feelings of kinship to non-blood-related associates manifests itself most evidently in the “band of brothers”. Relations in small military units are characterised by mutual support and respect, deep loyalty and shunning of anyone not seen as contributing. Men might go to war for idealistic patriotism, financial need, conscription and so on; but when the guns start firing, it is about your team.
In fact, any shared experience can create an ingroup. German and British soldiers notably left their trenches during Christmas of 1914, exchanged food and played football. They saw themselves, however briefly, as sharing the experience of being in the trenches, rather than as polar opposites bound to kill each other. (And why not, given that most of them would have had more in common with each other than with their generals.) Military trainers understand this, and as such, training usually disorients, exhausts and demeans recruits while breaking their links with the outside world. “[T]he main point is to awaken and intensify the instinctive predispositions of team aggression, producing warriors imbued with intense loyalty to those who have gone through the same training.” (Watch Full Metal Jacket for an illustration of this phenomenon.)
The important thing, of course, is to get ’em while they’re young. When boys hit puberty, the “innocence” of childhood turns into the sexual drive, competitiveness and risk-taking behaviours of early adulthood. “Their experience is limited, the drives are strong, and the rewards can seem great and death remote.” Growing up and living in the right conditions, young men could become master chess players or manipulated as a lethal force. Turning ex-child soldiers into normal boys again is an uphill battle waged against memories of the thrill and camaraderie of blowing things up with friends and wielding absolute power of life and death over terrified masses.The Nazis involved boys in military training from an early age. By 1936, 90% of German boys were in the Hitler Youth, and a few years later, 900,000 of them took part in a Nuremberg rally. It was a camping holiday filled with games and singing. What boy would not have enjoyed it? The Nazis actively encouraged the natural tendency for boys to rebel against their parents. Obedience to the group (and the Führer, of course) was essential, and cowards were ostracised. They fought furiously as part of the Wehrmacht as Hitler became more desperate and recruited younger soldiers, believing in “final victory”, while more mature minds knew it was naive. (Mao’s charisma and ideals–not to mention propaganda–recruited millions into the Red Guard in China during the Cultural Revolution.) These leaders understood human nature and how to manipulate it.
Potts and Hayden are disappointingly brief and non-committal on the biological roots of terrorism. Terrorism is more like tribal raiding than conventional war. They describe it as “a particular kind of team aggression–built very much upon ingroup identity, the desire for revenge, and a lack of empathy for the outgroup–[that] has taken on a profile out of all proportion to the number of warriors involved.” They touch on suicide bombing, as it is hard to see at first how suicide attacks could represent a successful evolutionary strategy. The sexual allure of the suicide bomber might suggest that embracing death can create new reproductive opportunities. It could also be altruistic behaviour that aids the survival of the killer’s genes. It may only be a stretch of the imagination (but not of the genes) to extend that idea to the entire national group.
The Yanomamo–our modern ancestors?
”It has become almost obligatory to mention the South American Yanomamo in any evolutionary discussion of warfare,” says Douglas P. Fry. The Yanomamo are an ethnic group in the Amazon who have fascinated anthropologists with their apparently violent ways. “Violence is ubiquitous in Yanomamo society,” claim Potts and Hayden. Yanomamo men are said to beat their wives as a warning to stay away from other men and capture women as wives in raiding parties. Men hold chest-pounding duels, wherein one men runs up to the other and punches him in the chest as hard as possible. (This form of non-lethal fighting is probably an antidote or alternative to more pernicious violence. After all, some men engage in hand-to-hand combat with their friends for fun.) Like their discussion of terrorism, the authors’ look at the Yanomamo is somewhat superficial, not explained clearly in evolutionary terms and better examined elsewhere.
In Beyond War, Fry takes up the claims against the Yanomamo. Commentators tend to assume the Yanomamo accurately represent our putatively-warlike ancestors, even though they are sedentary horticulturalists and our ancestors were hunter-gatherers; and despite the fact that bands (like our ancestors) do not form coalitions as readily as tribes (which are bigger, like the Yanomamo). Arguments from Yanomamo violence also tend to ignore differences in social organisation, and Yanomamo social organisation did not exist in ancient times. In his discussion of them, Fry points out that much of what is “known” about the Yanomamo comes from a study by Napoleon Chagnon, which has been much contested since. Chagnon found that unokais, Yanomamo men who have participated in killing and undergone a purification ritual, tended to have more than two and a half times the number of wives and three times the number of children as non-unokais of the same age. Fry takes issue with this study, pointing out that the two sample groups were not of the same age, and that the unokais as a group are at least 10 years older than the non-unokais. Neither did Chagnon’s study take into account that tribal leaders tend to have more wives and children than other men. There may be no difference between the reproductive success of those who have killed and those who have not.
Is war in our nature?
Fry, in fact, is not convinced that we evolved a propensity to war at all. The widespread (not universal) occurrence of warfare does not mean engaging in warfare is adaptive or provides reproductive benefits. Moreover, it seems to have occurred only very recently in human history, and was not present hundreds of thousands of years ago.
The fact that men are bigger, stronger and more aggressive than women is also no indication that they are adapted to war. These differences hold true over innumerable animal species that lack anything resembling war. Since male aggressivity is flexible, and can manifest itself in sports, business, and so on, it is the environmental conditions under which violence and war occur that need to be taken into account when considering human nature and violence.
Contrary to what Konrad Lorenz said in his influential tome On Aggression, human aggression is not inevitable, and contrary to Thomas Hobbes’ Leviathan, humans are not warlike by nature. Saying that we are means there is no point trying to reduce or eliminate war. Why attempt the impossible? But these are simply cultural beliefs that we are socialised to hold.
Fry takes a macroscopic anthropological view of human aggression, suggesting war can be replaced by “more effective, less brutal ways of seeking security, defending rights and providing justice for the people of this planet.” All humans seek justice, though their methods vary. Some favour violence and some don’t. Much of the violence humans inflict on each other, which may have been called “senseless” or “evil”, is a consequence of the desire to right wrongs.
War is part of our culture
The media distort our perceptions of the amount of violence in society because so much of what we watch features violence. And yet, most adults spend almost every day without purposefully inflicting injury on others, being the victim of aggression or even witnessing someone else’s victimisation. Not only is this true of us in our culture, but the same holds even for the most statistically violent cultures in the world. The cross-cultural data show that “violence [is] the shocking exception” among the countless peaceful solutions we find to our conflicts such as negotiating, agreeing to provide compensation for damages, reaching compromises, forgiving and reconciling with friends and strangers alike. “Humans have a solid capacity for getting along with each other peacefully, preventing physical aggression, limiting the scope and spread of violence, and restoring peace following aggression.” These findings should not only change our understanding of war but our ideas about the necessity of standing armies, the purpose of military intervention and the possibility for non-violent conflict resolution.
We project backwards. Because we are accustomed to seeing war in our world, we assume that war is eternal. In 1925, Professor Raymond Dart discovered fossil skulls from two to three million years ago he named Australopithecus africanus. He interpreted fractured skulls and shattered bones as proof that our ancestors killed and ate each other. But his extrapolations were disputed. Some of the shattering of the bones was undoubtedly due to the rock and dirt that pile on top of bones during fossilisation. Large predators plausibly account for the holes in the skulls. Dart believed, like most of his contemporaries, that man was inherently warlike and vicious. After all, World War One had ended only a few years earlier. A violent world was the world with which Dart was most familiar. But it is not necessarily the world of the australopithecines. Dart himself, in fact, accepted the alternative explanations when he realised they were more likely. We view our world as simply a technologically advanced version of the ancient world, but there is no reason why we should limit our imaginations this way. (Potts and Hayden mention Dart but do not discuss the controversy of his initial beliefs.)
Some anthropologists who claim that war is universal tend to include homicide in the definition of war. But homicide and war have different causes. Meanwhile, as Fry quotes Johan van der Dennen, “[p]eaceable preindustrial people constitute a nuisance to most theories of warfare, and they are thus either explained away, denied or negated.”
Do all cultures have war?
Studies show that nonwarring societies do exist. The very fact that they exist seems to disprove, or at least call into question, the idea that man is naturally warlike. All human societies have believers in the supernatural, music and property, as well as rape, revenge and murder. Not all societies have warfare. In fact, at least 70 cultural groups do not engage in war at all. Apart from many smaller groups such as the Semai of Malaysia or the Amish, one could cite Sweden and Switzerland, having gone many years without war, Iceland, 800 years without war, and Costa Rica, which disbanded its military after World War Two.
One of many examples of cultural groups who have not developed war is Australian Aborigines. Aborigines, under very different conditions from our own, developed relatively peaceful cultures. Bands that could have fought traded instead. They tended to respect each other’s territory. Band membership was open and fluid, and people had relatives and contacts in other groups (which is one reason I doubt the US and China will go to war). They also had advanced dispute-resolution mechanisms, such as duels, contests, meetings and reconciliation ceremonies.
Potts and Hayden consider archaeological and anthropological evidence but in less detail. They discuss several individual cases of group violence, arguing that the evidence that man has a penchant for blood is “abundant”. Fry’s approach seems to take a wider look but both points of view may be valid.
Can we move beyond war?
Not only is war unnecessary and lethal, it is possible to change our behaviour. Humans are so flexible that they can do various jobs in all kinds of societies and cultures. Says Fry, “the transition from the millenia-old lifeways of the nomadic forager band to the conditions of the urban, industrial nation is truly staggering. Yet we high-tech folks of the twenty-first century rarely pause to consider the immense plasticity in the nature of our species that allows a hunter-gatherer primate to live in this Internet world of strangers, stock exchanges and cruise missiles.” As long as we know it is possible to end war and make peace, we are capable of it.