Frans de Waal stands in a watchtower at the Yerkes National Primate Research Center north of Atlanta, talking about war. As three hulking male chimpanzees and a dozen females loll below him, the renowned primatologist rejects the idea that war stems from “some sort of blind aggressive drive.” Observations of lethal fighting among chimpanzees, our close genetic relatives, have persuaded many people that war has deep biological roots. But de Waal says that primates, and especially humans, are “very calculating” and will abandon aggressive strategies that no longer serve their interests. “War is evitable,” de Waal says, “if conditions are such that the costs of making war are higher than the benefits.”
War evitable? That is a minority opinion in these troubled times. For several years I’ve been probing people’s views about war. Almost everyone, regardless of profession, political persuasion, or age, gives me the same answer: War will never end. I asked 205 students at the college where I teach, “Will humans ever stop fighting wars, once and for all?” More than 90 percent said no. This pessimism seems to be on the rise; in the mid-1980s, only one in three students at Wesleyan University agreed that “wars are inevitable because human beings are naturally aggressive.”
Asked to explain their views, most fatalists offer variations on Robert McNamara’s remarks in the documentary The Fog of War. “I’m not so naive or simplistic to believe we can eliminate war,” said McNamara, who was the U.S. defense secretary during the Vietnam War. “We’re not going to change human nature any time soon.” War, in other words, is inevitable because it is innate, “in our genes,” as my students like to put it.
This dark outlook seems confirmed not only by the daily barrage of headlines from war-torn regions around the world—Iraq, Afghanistan, Congo—and the seemingly endless threat of terrorism, but also by findings from primatology, anthropology, and other fields. Over the last few decades, researchers in Africa have observed males in rival troops of chimpanzees raiding and killing (video) each other. Archaeologists and anthropologists also keep unearthing evidence of warfare in their studies of prehistoric and tribal human societies.
De Waal acknowledges that “we have a tendency, and all the primates have a tendency, to be hostile to non–group members.” But he and other experts insist that humans and their primate cousins are much less bellicose than the public has come to believe. Studies of monkeys, apes, and Homo sapiens offer ample hope that we can overcome our aggressive tendencies and greatly reduce or maybe even eliminate warfare.
Biologist Robert Sapolsky is a leading challenger of what he calls the “urban myth of inevitable aggression.” At his Stanford University office, peering out from a tangle of gray-flecked hair and beard, he tells me that primate studies contradict simple biological theories of male belligerence—for example, those that blame the hormone testosterone. Aggression in primates may actually be the cause of elevated testosterone, rather than vice versa. Moreover, artificially increasing or decreasing testosterone levels within the normal range usually just reinforces previous patterns of aggression rather than dramatically transforming behavior; beta males may still be milquetoasts, and alphas still bullies. “Social conditioning can more than make up for the hormone,” Sapolsky says.
Environmental conditions can also override biology among baboons, who, much like chimpanzees, seem hardwired for aggression. Since early 1978, Sapolsky has traveled to Kenya to spy on baboons, including Forest Troop, a group living near a tourist lodge’s garbage dump. Because they had to fight baboons from another troop over the scraps of food, only the toughest males of Forest Troop frequented the dump. In the mid-1980s, all these males died after contracting tuberculosis from contaminated meat.
The epidemic left Forest Troop with many more females than males, and the remaining males were far less pugnacious. Conflict within the troop dropped dramatically; Sapolsky even observed adult males grooming each other. This, he points out in an article in Foreign Affairs, is “nearly as unprecedented as baboons sprouting wings.” The sea change has persisted through the present, as male adolescents who join the troop adapt to its mores. “Is a world of peacefully coexisting human Forest Troops possible?” Sapolsky asks. “Anyone who says, ‘No, it is beyond our nature,’ knows too little about primates, including ourselves.”
