War: What is it good for?

by Ian Morris

  The chimps’ only weapons are fists, teeth, and the occasional rock or branch, but even an elderly chimp can hit harder than a heavyweight boxer, and their razor-sharp fangs can be four inches long. When they find enemies, they fight to kill, biting through fingers and toes, breaking bones, and ripping off faces. On one occasion, primatologists looked on in horror as attackers tore open their victim’s throat and yanked out his windpipe.

  So Lord of the Flies would seem to have gotten it right: the Beast is part of us, close, close, close. But, as usually happens in new scientific fields, it quickly turned out that things were more complicated. When I brought up the Lord of the Flies theory in Chapter 1, I immediately had to add that a trip across the South Seas to another island, Samoa, put things in an entirely different perspective. There, Margaret Mead found evidence that convinced her that she had stumbled onto a Pacific paradise, where violence rarely reared its ugly head. In a similar way, if we leap six hundred miles across the mighty Congo River from Gombe to a different patch of African rain forest, called Wamba, it feels as if we have followed Alice through the looking glass into Wonderland.

  On December 21, 1986, the primatologist Gen’ichi Idani was sitting at the edge of a clearing. He was waiting to see a party of apes pass through, but to his astonishment, not one but two parties simultaneously showed up. If Idani had been at Gombe, things might have turned very nasty in the next few minutes. There would have been threatening hoots between the parties, followed by mock charges and branch-waving. Under the wrong circumstances, there might have been fighting and death.

  At Wamba, though, none of that happened. The two parties sat down a few yards apart and stared at each other. After half an hour, a female from what the primatologists were calling the P-group got up and ambled across the open ground toward a female from the E-group. A moment passed, and then the two females lay down facing each other. Each spread her legs; they pressed their genitals together. They started moving their hips from side to side, faster and faster, rubbing their clitorises together and grunting. Within minutes both apes were panting and shrieking, hugging each other tightly, and going into spasms. For a tense moment both fell silent, staring into each other’s eyes, and then they collapsed, exhausted.

  By this point, the distance between the two parties had dissolved. Almost all the apes were sharing food, grooming, or having sex—male with female, female with female, male with male, young with old, with hands, mouths, and genitals mingling indiscriminately. They were making love, not war (Figure 6.4).

  Figure 6.4. Hippie chimps: two female bonobos in the Congo Basin engaging in what scientists call genito-genital rubbing

  Over the next two months, Idani and his colleagues watched the P- and E-groups repeat this scene some thirty times. Not once did they see anything like the violence of the Gombe chimpanzees—but that was because the apes of Wamba were not chimpanzees. Not the same kind of chimpanzees, anyway. Technically, the Wamba apes were pygmy chimpanzees (Pan paniscus), while the Gombe apes were regular chimpanzees (Pan troglodytes).

  To the untrained eye the two species are almost indistinguishable, the pygmy variety being just slightly smaller, with arms and legs a little longer and thinner, mouths and teeth a little smaller, faces a little blacker, and hair parted in the middle (primatologists only identified Pan paniscus as a separate species in 1928). The differences between them, though, help us answer the fundamental question of what war is good for, and what will happen to humanity in the twenty-first century.

  Pygmy chimpanzees (to avoid confusion, scientists usually call them bonobos; journalists often call them hippie chimps) and regular chimpanzees (usually just called chimpanzees, without any qualifying adjective) have almost identical DNA, having diverged from their shared ancestor just 1.3 million years ago (Figure 6.5). Even more surprisingly, the two kinds of apes are genetically equidistant from humans. If chimpanzee wars suggest that humans might be natural-born killers, bonobo orgies suggest we could equally well be natural-born lovers. Rather than pulling out their swords and stabbing at the Graupian Mountain, Agricola and Calgacus might have torn off their togas and rubbed their genitals together.

  Figure 6.5. The family tree: the divergence of the great apes from our last shared ancestor fifteen million years ago

  Explaining why there was stabbing rather than rubbing in A.D. 83 will also show us why, after ten thousand years of regularly choosing war over words, we did not go ahead and blow the world to pieces in the later twentieth century. It will also hint at how we might maintain this record in the twenty-first. But it is a long story—3.8 billion years long, in fact.

  The Game of Death

  In the beginning, there were blobs.

  At least, that is what biologists often call them: short chains of carbon-based molecules held together by crude membranes. These blobs began forming about 3.8 billion years ago, through chemical reactions between simple proteins and nucleic acids. The blobs grew by absorbing chemicals, and when they got too big for their membranes, they split into multiple blobs. Each time a blob split, its component chemicals knew how to re-combine into new blobs because the ground plan for blobbishness was encoded in ribonucleic acid (RNA), which told proteins what to do. Undramatic as it sounds, this was the beginning of life.

  Darwin famously defined evolution as “descent with modification.” RNA (or, in complicated life-forms such as ourselves, DNA, deoxyribonucleic acid) copies genetic code almost—but not quite—perfectly, introducing random genetic mutations. Most of these made little difference to the blobs; a few were catastrophic, causing the blobs to break apart (killing them, we might say); and others made the blobs replicate better. Over time—a lot of time—more efficient blobs outreproduced less efficient blobs.

  Evolution may be the one thing in the world that is even more paradoxical than war. Natural selection is a competition, but the biggest rewards go to cooperation, resulting—to cut this 3.8-billion-year-long story short—in the evolution of ever-more-complex carbon-based life-forms that cooperate and compete in extraordinary ways.

  Three hundred million years of random genetic mutations produced blobs able to cooperate well enough to form cells (more sophisticated bundles of carbon-based molecules clustered around strings of DNA). Cells outcompeted blobs for access to energy in the earth’s primeval oceans, and by 1.5 billion years ago had become much more complicated. For the previous 2 billion years, all life had reproduced by cloning, and mistakes in genetic copying were the only source of modification. The new cells, however, could cooperate by sharing the information in their DNA—that is, by sexual reproduction. Sex massively increased the variation in the gene pool, sending evolution into overdrive. By 600 million years ago, some cells were sharing genetic information so thoroughly that they could band together by the millions to make multicellular organisms (our own bodies contain about 100 billion cells each).

  The cells in these animals cooperated by taking on different functions. Some turned into gills and stomachs to process energy in new ways; others into blood, to carry this energy around the body; and others still into shells, cartilage, and bones. By 400 million years ago, some fish found their gills turning into lungs and their fins into feet; they invaded the land.

  The cells in fins or feet did not compete with those in stomachs or bones; instead, they cooperated to make a creature that could compete more successfully against other clusters of cells to get the energy that all such animals needed. The result was an evolutionary arms race. It took hundreds of millions of years, but some cells specialized to be sensitive to light, sound, touch, taste, or smell, and the resulting eyes, ears, skin, tongues, and noses gave animals information on where to go and what to do. Nerves carried this information to a single point, normally at the front end of the animal, where they knotted together into tiny brains.

  Animals that became aware of their own bodies—where their skin was, where they themselves ended and the rest of the world began—tended to compete better than those unaware of suc
h boundaries, and those aware of their own awareness competed better still. The brain became conscious of the animal it was lodged within as an individual; it formulated hopes, fears, and dreams. The animal became an “I,” and mind came into the world.

  That the blind, undirected process of descent with modification has over the last three billion years turned carbon blobs into poets, politicians, and Stanislav Petrov does seem like something of a miracle, and we need hardly be surprised that until Darwin’s day almost every human who ever lived saw the hand of god(s) behind the wonder of life. But this astounding story also had a darker side.

  Around 400 million years ago, the mouths of some fish sprouted cartilaginous teeth, sharp enough—and set in jaws strong enough—to tear the flesh of other animals. These proto-sharks had found a shortcut in the competition for energy. They could steal the energy locked up in other animals’ bodies by eating them, and if they bumped into other proto-sharks competing for the same piece of food or the same sexual partner, they could fight. Teeth raised competition to a new level, and other animals responded by growing scales for defense, speed for fleeing, and teeth of their own (or stings, poison sacs, and—on land—claws and fangs) for striking back. Violence had evolved.

  This did not turn the world into a free-for-all. When one animal runs into another that can fight back, it thinks twice before attacking. Animals that are heavily armed with fangs and claws will growl, bare their teeth, or puff up feathers or fur rather than simply assaulting one another. If bravado fails and the rival does not crawl, run, swim, or fly away, things may reach the point of locking horns or butting heads until one contestant recognizes that it is losing and yields. But tussling like this is a risky business, regularly causing serious injuries, and every species has evolved ways to avoid actual fighting through elaborate signals of submission, such as groveling, presenting bellies or rears, and even urinating with fear.

  Explaining this behavior will provide the key to making sense of much of the behavior we saw among our own species in Chapters 1–5, but to get to the answers, we must turn from biology to mathematics. Imagine, mathematicians say, two animals simultaneously coming across a tasty morsel or available mate. Will they fight? All kinds of factors will play into the decision, and no two animals will act in exactly the same way. Take my own two dogs. One, Fuzzy, thinks everyone is his friend, and he turns every encounter into a frenzy of tail-wagging, sniffing, and licking. The other, Milo, assumes that every other dog (except Fuzzy) is out to get him. There will be snarling, lunging, and straining at the leash; given the chance, he will bite first and sniff later.

  And yet, mathematicians observe, behind the almost infinite variety of animal personalities and actual encounters, there are patterns. Fighting has consequences for the participants’ genetic success. The effects can be direct, as when the winner passes on genes by procreating or the loser drops out of the gene pool by getting injured or dying, but more often they are indirect. A winner might eat, storing energy for procreating later, or win prestige, becoming more attractive to mates and more intimidating to rivals. A loser might go hungry or lose face.

  Few animals (including humans) calculate quite so coldly when a confrontation gets going; instead, we are taken over by hormones that have evolved precisely to help us make quick decisions. Chemicals flood our brains. We panic and run away, wag tails and approach, or see red—“the mad blood stirring,” said Shakespeare—and lash out in anger. The choices each animal makes, though, affect its chances of transmitting genes to the next generation, and thanks to the relentless logic of natural selection, behaviors that favor transmission gradually replace those that don’t.

  We might think of these confrontations, the mathematicians suggest, as games, and assign points on a league table of genetic success for the different moves an animal might make. Game theory (which is what scientists call this exercise) simplifies reality wildly, but it helps us see how each species—including humans—evolves its own balance between fight, fright, and flight.

  I will borrow an example from the evolutionary biologist Richard Dawkins. Let us say, he proposes in his bestselling book The Selfish Gene, that an animal that wins a confrontation picks up 50 points in the race for genetic success while one that loses gets 0. Getting hurt costs a player 100 points, and a long confrontation that wastes time (which could be more profitably spent eating or mating somewhere else) costs the animal 10 points.

  If the two animals facing off are doves (not real doves; this is mathematics, so “dove” is a symbol, standing for an animal that never fights), they will not come to blows. They both want the mate, food, or status under dispute, though, so a standoff ensues, with much puffing up and hard staring. This goes on until one bird loses patience and flies off. The winner then gets 50 points, but loses 10 for time wasted, for a net gain of +40. The dove that backs down scores –10 (0 gained and 10 points lost for its time). The average outcome of such face-offs, repeated millions of times over thousands of years, is +15 points (the winner’s 40 points added to the loser’s –10, divided by 2).

  But what if one of the doves is actually a hawk? (Again, this is a mathematical hawk, which just means an animal that always fights.) The hawk neither stares nor puffs up; it attacks, and the dove flees. If every confrontation this hawk gets into is against a dove, the hawk always scores 50 points (with no points lost, because no time has been wasted)—much more than the +15 a dove averages with its strategy. The result: hawkish genes spread through the dovish population.

  But now the paradox of evolution kicks in. As the number of hawks increases, it becomes more likely that a hawk will find itself facing another hawk rather than a dove, and both will attack. One hawk will win (+50 points; for simplicity’s sake, I will assume it is unhurt), and the other will be wounded, losing 100 points. The overall yield (50–100, shared between the two animals) is –25 points.

  In this situation, the remaining doves do rather well. Because they always flee, they always score 0 points, which is a lot better than the –25 that the hawks are making. Dove genes start spreading back through the population. The scoring system Dawkins deployed in this game means that the gene pool will drift toward a sweet spot—what biologists call an evolutionarily stable strategy—at which five out of every twelve animals act like doves and the other seven like hawks.

  Random mutations, luck, and all kinds of other forces constantly push the actual numbers away from this balance, only for the game of death to pull them back again. Each species, including our own, will have outliers—its Fuzzys and Milos—but most members are somewhere in the middle, nudged by the game of death toward the evolutionarily stable strategy, with its own distinctive form of violence.

  The abstract game of death lays bare the principles behind the use of force in every kind of animal. It suggests that our own violence, like that of other creatures, must be an evolutionary adaptation, descended with modification from the habits of ancestors millions of years ago. But at the same time, game theory also shows us the peculiarities of human violence. We regularly kill rather than just chase off enemies. Since winners who fight to the death face more risks than winners who accept submission, killers should on average get lower payoffs from the game of death than non-killers. He who fights and runs away lives to fight another day, and so does he who recognizes signals of submission and lets the loser go.

  So why, we have to ask, when Godi jumped out of his tree at Gombe in 1974 and ran for dear life, did the Kasekelans chase him, pin him down, and beat him to death? Why did they go on to kill the rest of the Kahaman males? Why have chimpanzees embraced lethal violence as part of their evolutionarily stable strategy? And why have we?

  A Little Help from My Friends

  Part of the answer is obvious. The attack that killed Godi differed in one crucial way from the abstract experiments of game theory: it was eight against one. The Kahaman chimp never stood a chance, and his attackers knuckle-walked away with barely a scratch on them. One of the Kasekelans was so
old that his teeth were worn down to stumps, but at those odds he happily joined in the bloodbath.

  Eight-to-one attacks are a special kind of violence, only possible for animals that can cooperate to form gangs. It has taken an awful lot of evolution to produce this blend of cooperation and competition. Three and a half billion years ago, some blobs evolved to cooperate so well that they could become cells, which could compete for energy more effectively than crude blobs. Around 1.5 billion years ago, some cells worked together so well that they could reproduce sexually, generating more mutations and offspring than asexual cells. By 600 million years ago, some of these complex cells were cooperating so much that they formed multicelled animals, with yet more advantages in the competition to pass on their genes. But only in the last 100 million years have some of these animals raised cooperation still higher, forming multi-animal societies.

  Biologists call these organisms social animals. All birds and mammals are at least slightly social, in that mothers and their young form strong bonds, but a few dozen species go well beyond this. They form permanent communities with anywhere from dozens to billions of members, each one of whom has his or her own functions in a larger division of labor. Only social animals can form gangs and engage in an activity like killing Godi.

  Humans, the cleverest animals on earth, are highly social. So too are dolphins, killer whales, and nonhuman apes, which also stand out for brainpower. But before we jump to the conclusion that braininess causes sociability, we should bear in mind that ants—arguably the most sociable animals of all—are also among the stupidest. Although ant cooperation reaches such heights that biologists call their colonies superorganisms, with millions of insects acting together as if they made up one giant animal, ant experts also call these superorganisms “civilization by instinct,” because individual ants have such sketchy mental lives that the knot of nerve endings in an ant’s head barely counts as a brain at all (“ganglion” is the preferred term).