The pacifist scientist who believes humans evolved to be violent

The pacifist scientist who believes humans evolved to be violent

Richard Wrangham’s research on chimps has led him to believe that humans are evolutionarily adapted for violence—but, he says, that shouldn’t preclude peace.

Richard Wrangham with chimp in background. Photo by Alex Georgiev.

Richard Wrangham with chimp in background. Photo by Alex Georgiev.

Richard Wrangham is a celebrity primatologist — the kind who, last winter, commanded a $25,000 per person price tag for a two-week safari to Uganda co-led with his friend and colleague at Harvard, cognitive scientist Steven Pinker. (Proceeds from the safari went towards the Kibale Chimpanzee Project, Wrangham’s nearly 30-year chimp study in Uganda.) Seduced both by the ideas and the execution of science, he’s as comfortable exchanging pet theories with colleagues in Cambridge as he is hacking through steep forest terrain in Tanzania. He is responsible for some of the most influential theories in human evolution, including the idea that we are biologically predisposed to violence. He is also an avid botanist, has eaten bushmeat, had a girlfriend who was kidnapped by guerrilla terrorists, and once asked Jane Goodall if he could live naked in the forest with the chimps they studied.

It was during his time as a research assistant for Jane Goodall that Wrangham witnessed his first acts of chimp aggression. It was the early 1970s, and he was stationed at Goodall’s field site in Gombe Stream National Park, Tanzania. One day he saw a group of chimps react to the cry of a single chimp from a neighboring group. “Their hairs became erect, they touched their genitals and the males ran toward the sound,” he said. “But, when they heard five more calls add to the first one, they immediately turned around and raced back to their site. They had wanted to beat up on the lone individual.”

“A lot of people like to think of chimps and other primates as being gentle, peaceful creatures, but Richard has explored some of their darker sides.”

Observations like this set the stage for Wrangham’s later theories on aggression in human males, which he summarized in a controversial 1997 book called Demonic Males. Now a professor of anthropology at Harvard, Wrangham believes that human males are biologically adapted for aggression, particularly when there’s an imbalance of power in their favor. “Natural selection favors aggression when there’s a low risk of cost to the individual,” he said.

This is one of three or four big ideas that have characterized Wrangham’s career as an illustrious primatologist and pioneer in the study of human evolution. He has also studied how female feeding patterns structure primate societies, how cooking led humans to evolve smaller jaws and larger brains, and, most recently, how self-domestication, or evolution away from aggression, occurred similarly in humans and other animals. In 1987, he won a MacArthur award for his work comparing the social behaviors of chimps and humans.

“Although many people rightfully point to Jane Goodall as kind of the founder of modern chimpanzee behavioral biology, it’s really Richard who was one of the great scientific innovators at the very beginning of research on chimp behavior,” said Daniel Lieberman, a researcher of human evolutionary biology and colleague of Wrangham’s at Harvard. “A lot of people like to think of chimps and other primates as being gentle, peaceful creatures, but Richard has explored some of their darker sides. His research has been immensely important in terms of how we think about human evolution and how to understand why we are the way we are.”

Wrangham’s fascination with nature began in the countryside of Yorkshire, England, where he spent his childhood birdwatching and playing hide-and-seek in the woods. Starting at age 15, Wrangham regularly went on overseas birdwatching expeditions. After high school, he took a gap year to conduct wildlife research in Zambia with John Hanks, an English zoologist who later became the international projects manager for the World Wildlife Fund.

In 1967, Wrangham started college at the University of Oxford. He read works by Australian zoologist Konrad Lorenz and American paleoanthropologist Robert Ardrey, both of whom believed that humans evolved to be aggressive to hunt animals and compete for resources with each other. Wanting to learn more about human evolution himself, Wrangham decided to study animals that share key social behaviors with humans.

He first set his sights set on a somewhat unlikely candidate: the banded mongoose. “They were also social animals that ate meat,” he explained. But Wrangham’s mongoose dreams never came to be—his department rejected his study proposal because he had poor grades. Around that time, his academic advisor had heard that Jane Goodall was looking for research assistants. He suggested that Wrangham write her a letter.

At the time, Goodall didn’t think there were social boundaries between chimpanzee groups.

From 1970 to 1975, Wrangham studied chimps in Tanzania, first as a research assistant for Goodall and then as a graduate student with Goodall’s old advisor, Robert Hinde, a zoologist at the University of Cambridge in England. He was the first person to do a doctoral thesis based on full-day field observations of chimps. For 12 hours each day, Wrangham followed the chimps he studied, taking painstaking notes by the minute when they stayed still and keeping pace with them when they roamed the steep forest terrain. He never found the work grueling. “It was just exciting,” he said. “I was discovering things I wanted to know.”

At the time, Goodall didn’t think there were social boundaries between chimpanzee groups. But that was because she didn’t follow the chimps to the edges of their ranges, Wrangham explains. “I was part of a generation picking up astonishing interactions at the edges of these boundaries,” he said. Once Wrangham and his field companions started performing full-day observations, they witnessed dramatic acts of aggression and warfare between males of neighboring chimp groups. It was typical, he said, to see a group of five to six chimps attack a single individual from a different group. “The victim would be torn up, with appalling cuts and bruises,” he said. “The aggressors wouldn’t have a single scratch on them.”

In addition to studying aggression, Wrangham helped identify chimp behaviors previously believed to be exclusive to humans, such as self-medication and culture. The notion that chimps had culture was controversial at the time, but Wrangham found differences in tool usage, grooming, and courtship between chimp communities that strongly supported it.

After leaving Tanzania, Wrangham spent fifteen years more years conducting research in Africa. In the early 1980s, he spent a year in the Democratic Republic of the Congo studying the mutualistic relationship between a partially nomadic group of forest pygmies and a nearby community of village farmers. The experience was his first foray into anthropological thinking and colored his interest in the dynamics of human societies.

During this period, Wrangham enjoyed stints at Stanford, Harvard, Cambridge and the University of Michigan in Ann Arbor, before winding up back at Harvard in 1989, where he has remained ever since. In addition to chimps and humans, Wrangham studied the social structures of baboons and vervet monkeys.

“Nobody, either primatologists or anthropologists, has had the kind of career he has had.”

At Harvard, Wrangham has continued to expand his ideas on human evolution through his combined lens of zoology, primatology and anthropology. Last September, along with his former student Michael Wilson and 28 other primatologists, he published a controversial paper in Nature arguing that chimps evolved to proactively seek out opportunities for coalitional violence. The study gave credence to his long-standing idea that human aggression has deep evolutionary roots.

Some researchers, however, questioned whether the study adequately differentiated between chimps’ innate aggression and their aggression in response to dwindling resources and human encroachment. “These theories make people think that chimps are nasty, terrible creatures,” said Robert Sussman, an anthropologist at Washington University in St. Louis, Missouri. “But they don’t consider that the chimps are going through all sorts of changes because of what humans are doing to their environment.”

Others accuse Wrangham of over-applying chimp models to human societies. Douglas Fry, an anthropologist at the University of Alabama, Birmingham, points out that chimps and bonobos are equally related to humans on the evolutionary tree. He questions the assumption that violent chimps are more relevant to human origins than bonobos, which are famously peace loving.

Fry also worries that Wrangham’s research contributes to a mass psychology that pits humans against each other and justifies actions like preemptive strikes in war. “It fills a societal expectation, a Hobbesian belief that humans are violently inclined,” he said. His own research on nomadic forager societies suggests, in contrast to Wrangham’s conclusions, that war between human groups is somewhat rare. “There’s very little violence between groups of nomadic foragers,” he said. “The majority of their killings are homicides, which tend to be very personal.”

But Wrangham believes scientists shouldn’t shy away from scientific fact just because it might have political implications. “None of the people who criticize this research have worked with chimps. Their objections are theoretical,” he said, “whereas all the people who work with chimps share the same view — you have to treat chimps very, very carefully.”

Wrangham says he subscribes to “typical left-wing UK” politics, and supports programs that anticipate and intervene against violence over those that try to reform people’s free agency. He applauds “worldwide systems to create peace,” including formal intergovernmental structures like NAFTA, the European Union or the United Nations. These beliefs stem from his conviction that people are, at their core, selfish and prepared to enact violence. “We should recognize that humans have a ready propensity towards violence,” he said, “and then try to minimize it.”

Richard Wrangham with Hadza in Tanzania. Photo by Matt, via Richard Wrangham.

Richard Wrangham with Hadza in Tanzania. Photo by Matt, via Richard Wrangham.

Wrangham doesn’t politicize his research, said Luke Glowacki, one of Wrangham’s current graduate students who studies warfare between nomadic pastoralists in Ethiopia. “He’s actually one of the biggest pacifists I’ve ever met,” Glowacki said. “But he goes where the research goes.”

Many advisors, Glowacki adds, would not let their students enter a war zone in a remote country for the sake of research. “But Richard understands what it means to really be driven by a question.” Wrangham’s other mentees also get to inherit this spirit of being seduced by an idea and chasing it as far as one possibly can. In addition to Glowacki, students in his lab are currently studying relationships between chimpanzee babies and adults, cooperation in indigenous Indonesian communities, disease ecology in chimps, behaviors within foraging communities in Botswana and the spread of infectious disease in Kenyan communities that live closely with rodents.

Wrangham, 66 years old, shows no signs of slowing. Now that their three sons are grown, he lives with his wife Elizabeth on Harvard’s campus, as House Master of an undergraduate dorm. As a teacher, he has a reputation of being a “sage on the stage” during lectures, said Zarin Machandra, a former graduate student of Wrangham’s who now co-directs his Kibale Chimpanzee Project. His latest intellectual pursuit is investigating how primates and other animals evolve away from reactive aggression, or self-domesticate- to increase their chances of mating and getting food. The research will be the foundation of his next book.

Touching on sex, diet and aggression, the topic of self-domestication ties together far-reaching questions Wrangham’s had since his earliest field experiences in Tanzania. “Nobody, either primatologists or anthropologists, has had the kind of career he has had,” said Machandra. “He sees connections many of us only wish we could see.”

Wrangham himself feels lucky to be exploring these evolutionary questions now. “It wasn’t until the 1960s that people started saying, ‘well, ok, evolution really works, so let’s now try to understand how we are adapted and why,’” he said. “So we live in a really exciting time, if you’re thinking about some of the deep questions: exploring the nature of humans, who we are and what we are doing on Earth.”

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