What If Man Is a Killer Ape Beset by Original Sin?

A new book probes the roots of humans' destructive impulses.

Creatures of Cain: The Hunt for Human Nature in Cold War America, by Erika Lorraine Milam, Princeton University Press, 408 pages, $29.95

Today, self-help books and relationship gurus invoke evolution to explain everything from marital infidelity to the paleo diet. Our early ancestors' survival needs echo through our ideas today. But this is not the first time our hominid ancestry's role in our culture and character has played a major role in Western popular culture.

Following the nightmare of the Second World War, the idea of a universal humanity had great appeal. The Holocaust and the atom bomb had proven that human beings have not only destructive impulses but a devastating ability to carry them out. But were these impulses something we were born with, or were they created by our culture? Answering this question became a driving focus of popular anthropology. With Creatures of Cain, the Princeton historian Erika Lorraine Milam explores this period of intellectual debate.

The high-minded internationalism of the postwar period sought to promote a sense of brotherhood, as in the "Family of Man" exhibit at the Museum of Modern Art in 1955—photographs showing the lives of people around the world. (This still, rather parochially, treated the nuclear family as the center of all cultures.) Anthropology hadn't covered itself in glory in the previous 50 years: Some of its biggest names, such as Earnest Hooton and Eugen Fischer, had gone all in on the "race science" that drove Nazism and eugenics. The S.S. doctor Josef Mengele even received funding from the Rockefeller Foundation before he went to Auschwitz. So after the war, many scholars believed the path to peace (and academic redemption) was to celebrate the universal family of man, playing down differences and pointing to humankind's immense achievements, from agriculture to rocket science. Violence was aberrant and abhorrent; our true nature was to cooperate. Some scientists, such as Margaret Mead, even argued that behavior, whether cooperative or competitive, was entirely learned. We are made by our cultural environment, so cultures could create peace.

In the '50s and '60s, magazines like National Geographic and Scientific American published stories on various "Stone Age" cultures still alive in the world, from the Kalahari Bushmen to the tribes of New Guinea. The stories highlighted the idea that such peoples represented the lives of our hominid ancestors and focused on how they lived in harmony with nature. There was also a sense of urgency to study these groups before they were changed by contact with the rest of the world.

This idealization of tribal peoples was hardly new—some of that fawning coverage could have been written by Jean-Jacques Rousseau. Unfortunately, other studies offered less comforting visions in which these "primitive" groups turned out not to be soft-focus prelapsarian Adams after all. Indeed, some of them were pretty violent.

Meanwhile, other scientists treated baboons, chimpanzees, or gorillas as analogs to early man, using them to look for clues to our ancestral patterns. But Jane Goodall's research found that life among chimps was not idyllic either. Territorial warfare, murder, and infanticide were part of their world too.

So the idea that our species is naturally cooperative was changing by the mid-1960s. The "Killer Ape" thesis, popular from about 1966 to 1975, held that human beings are violent because of our genes. Milam argues that Americans' understanding of human nature shifted rapidly "from seeing humanity as characterized by our unique capacity for reasoned cooperation to emphasising, even lauding, our propensity for violence."

One key advocate of this view was the science writer Robert Ardrey, who published The Territorial Imperative in 1966. He argued that competition for territory was part of human character. Around the same time, Konrad Lorenz's On Aggression and Desmond Morris' The Naked Ape appeared in bookstores.

Morris' focus was on sexual behavior, which he argued was different from that of other primates due to humans' relative hairlessness, which rendered our primary and secondary sexual characteristics more visible. He argued that breasts had developed for sexual signaling as well as for feeding infants and that sexual selection had favored men with large penises. The Naked Ape's message was in keeping with the sexual revolution, and the book became a bestseller, reaching readers well beyond the kinds of people who would normally buy books on anthropology. (A Johnny Carson interview with Morris was, by Milam's account, the first time the word penis was said on live American television.)

A number of the experts involved were also focused on public communication. Milam suggests that a sharp line cannot be drawn between the "colloquial" and academic discussions taking place, since several scientists were participating in the public sphere. Their books were published by commercial presses; they appeared on TV; the debate played out not just in Nature but in the letters page of Playboy. (Hugh Hefner liked The Naked Ape and even sponsored a film adaptation of the book. The idea that promiscuity was biologically determined obviously played well with much of Hef's audience.)

It is worth noting that some of the prominent figures in this intellectual debate had no advanced credentials in the field. Ardrey, who was well-known as a Hollywood screenwriter, had no training beyond an undergraduate degree in anthropology. Jane Goodall had not been to college at all when she began her chimpanzee research. (She would later complete a Ph.D. after being admitted directly to a graduate program on the basis of her published work.) Those who did have advanced degrees and university appointments could suddenly attract the kind of attention most academics only dream of. Lionel Tiger, the Rutgers anthropologist who wrote Men in Groups (1969), was profiled like a rock star in The New York Times. Tiger argued that homosocial groups of men formed the foundation of human society. (It was Tiger who introduced the phrase male bonding to common conversation.) The writer Kate Millett called it "a genetic justification of the patriarchy"—and it wasn't only feminists who found the idea of such innate social behavior depressing.

The popularity of these human evolution books made them ripe for parody, by writers such as Elaine Morgan in The Descent of Woman (1972) and Antony Jay in Corporation Man (1971). In his witty account of businessmen (Homo sapiens corporalis), Jay—the future co-writer of the TV show Yes, Minister—mocked the participant-observer anthropologist, saying that he was "accepted so completely by the objects of my study that my presence in no way inhibited or modified their behaviour. Indeed, there were times when I could honestly say that I felt I was one of them myself." Morgan similarly suggested that readers try to observe "specimens of Homo sapiens in his natural habitat. It shouldn't be difficult because the species is protected by law and in no immediate danger of extinction."

This wave of books would give way to further, more nuanced discussions of evolution and its impact on human behavior. E.O. Wilson's Sociobiology(1975) attempted to synthesize group and individual selection pressures, including cooperative as well as competitive traits. Richard Dawkins entered the fray in 1976 with The Selfish Gene, the most popular book about the new evolutionary theories. Dawkins' work focused on individual genetic survival, explaining even cooperation as a strategy for gene transmission. More recently, Steven Pinker's The Blank Slate (2002) came close to capturing the kind of crossover appeal of the Killer Ape genre.

Today, evolution is widely accepted as an explanation not just for how we got here but for how we are. But the understandings of it among the public are not always what scholars have intended. Far from promoting equality, it can be used to justify division. Just as religions could be interpreted as endorsing hierarchies, so evolution could be used to denigrate certain groups who were seen to be at "different stages of development," an idea that appeared soon after Darwin published The Origin of Species.

This mindset was especially widespread in the late 19th and early 20th centuries. From the Enlightenment view of "savages" as less culturally developed, evolution allowed Westerners to see them as less biologically developed too, an idea that was weaponized in various forms of colonial oppression. This "scientific racism" was not eradicated with notions of universality. When scholars themselves point to "primitive" tribes as representing how our ancestors might have lived, it's not hard to see how the average reader would interpret that as meaning these indigenous groups were less far along the evolutionary track than Westerners.

Today, DNA testing is widespread—for criminal investigations, for medical diagnoses, for genealogical research. The idea that our genome offers something of a road map for our behavioral characteristics is widely accepted, although the nature/nurture debate does continue.

But the idea that we would instinctively fight and fornicate, were it not for the moderating influence of modern civilization, wasn't created by the Killer Ape theorists. It was the general understanding of the Christian world. We were creatures of Cain. Our ability to control our behavior—our higher consciousness—was what separated us from the animals. Whether we label those instincts "DNA" or "original sin," the idea is the same.