In twenty-three years of marriage my wife and I have owned (or been owned by) five cats, quintessential Brooklyn pets draped over sofas and coffee tables, masters of the plaintive mew and the food-bowl stare. Four of the five have had “socks,” white fur along the fore and hind paws, contrasting handsomely, in our nonbiased opinions, with patches of gray and calico. As Richard Wrangham’s The Goodness Paradox: The Strange Relationship Between Virtue and Violence In Human Evolution explores in rich detail, these sock feet aren’t mere decoration but rather a signature of an ornate domestication process, one with profound implications for Homo Sapiens. To understand our humanity, Wrangham suggests, we can look to cats and dogs — and even foxes — for answers.
The Goodness Paradox is a tale of two books. A Harvard professor of biological anthropology, a primatologist, and the recipient of a MacArthur “genius” grant, Wrangham brings sterling credentials to a novel if plodding quest. The first half is maddeningly repetitive and often textbook-dull; Wrangham can’t quite shed the tweeds and lecterns of academia. He neglects to shore up his arguments with genetic data. But as its pieces jigsaw into place, The Goodness Paradox picks up velocity, its themes emerging with force and clarity.
His introduction poses twinned questions: “If we evolved to be good, why are also so vile? Or if we evolved to be wicked, how come can we also be so benign?” A few pages later he lays out the terms on which he’ll build his investigation: “humans are positively dualistic with respect to aggression. We are low on the scale of one type (reactive aggression), and high on the other (proactive aggression). Reactive aggression is the ‘hot’ type, such as losing one’s temper and lashing out. Proactive aggression is ‘cold,’ planned and deliberate . . . we practice exceptionally low levels in our day-to-day lives, yet we achieve exceptionally high rates of death in our wars. That discrepancy is the goodness paradox.”
And off we go. Wrangham taps a deep aquifer of experience, including decades of fieldwork in Africa. Although closely related – they weren’t identified as distinct species until 1933 — chimpanzees and bonobos probably diverged with the formation of the Congo River nearly two million years ago, tacking in strikingly opposing directions. Chimpanzees display all kinds of brutal, even lethal violence to each other while bonobos thrive in peace, making love, not war. Wrangham also highlights subtle physiological nuances: bonobos’ skulls are smaller, their torsos more gracile, with less variance between females and males. In his view they are domesticated chimpanzees, as dogs are domesticated wolves.
Darwin had first stumbled across this concept in The Descent of Man, published in 1871, but the critical breakthrough came nearly a century later, when the Soviet geneticist Dmitri Belyaev discovered that silver foxes could be bred for domestication in as few as ten generations. (Domestication is not tameness; one can tame a wild animal without domesticating it.) Belyaev noticed both behavioral and physical adaptations: unlike the control group, the experimental group’s skulls narrowed, their ears flopped and their tails curled, characteristics unknown in the wild. Starbursts of white fur whorled on their foreheads, markings found in dogs and cats and connected to the sock feet we see in our pets. (Wrangham attributes these markings to “neural-crest migration,” a cellular process that occurs in embryos.) The sexes drifted nearer in appearance. Belyaev repeated the experiments with mink and rats; all responded in the same manner. Non-adaptive traits piggybacked, from male nipples to penises and clitorises in waterfowl (most birds have neither) to even sexual preference. While same-sex copulation has been documented in a plethora of species, there’s only one other, besides humans, that will engage in exclusively homosexual relations: sheep. (Amid his professorial delivery Wrangham pings us with a hilarious aside about gay rams.)
The Goodness Paradox then homes in on Homo Sapiens. Ideally we would compare ourselves to Pleistocene humans, but a dearth of early bones and other fossils re-directs us to our sister species, Neanderthals, who went extinct about 40,000 years ago after brushing against and occasionally mating with our ancestors. Again, the physiological arc leaps out: humans are lighter-boned, with smaller brains and less body differences between the sexes. As our faces thinned our skulls morped into globes, giving the prefrontal cortex more space to “inhibit,” or regulate, our emotions. (Humans have about sixteen billion neurons in each brain, as opposed to the distant runners-up, elephants and other great apes, at six billion.) We dialed down the reactive aggression in order to get along with one another – and thereby survive. Language, too, may have abetted cooperation among individuals, thus conferring a selective advantage, although the minute differences between human and Neanderthal DNA can’t tell us for sure whether Neanderthals had language.
Once The Goodness Paradox has methodically mapped out self-domestication and its selective underpinnings, the book shrugs off its academic chrysalis; its prose eases into graceful lines, mimicking the syndrome itself. Wrangham moves beyond biological survey into the realms of politics and philosophy. As humans selected for reduced reactive aggression they pumped up proactive aggression, with capital punishment as the mechanism. Although the Pleistocene evidence is scant, some bones reveal traces of human-on-human violence. The advent of agriculture and the rise of cultures increased the incentive to punish aggressors, often without rhyme or reason. “Executions and the reasons for them have been described in every society with written record,” Wrangham notes. “Capital punishment . . . happened not only for violent crimes but also for nonconformism (as in Socrates’ case), for minor felonies, and even some heartbreakingly trivial matters such as malpractice in selling beer (according to the Code of Hammurabi), or stealing the keys to one’s husband’s wine cellar (according to the laws of the early Roman Republic) . . . They continued in all historically known societies until the 1764 publication of On Crimes and Punishment, by the Italian jurist Cesare Beccaria . . . [which] helped launch the change that continues today in community attitudes toward capital punishment.”
If a Brutus seeks to remove an autocratic Julius Caesar, he’ll devise a plan with scores of conspirators and mark his calendar for the Ides of March. This is the essence of proactive aggression: collaborative, coolly premeditated, with a strong chance of success. An assassination is a coup in miniature; a coup can escalate into war; bloodshed begets bloodshed, the building blocks of civilization. Humanity has selected for lower reactive aggression in order to confer an evolutionary benefit – cooperation — with an uptick in proactive aggression as the countervailing weight. “On average, everybody benefits,” Wrangham observes, but the upshot is “a new kind of dominance…the limited power of a single alpha became the absolute power of a male coalition.”
This Darwin-meets-patriarchy phenomenon, which places a small cadre of powerful men at the top of the social ladder, has conjured nations from tribes, cultures from scratch, Renaissance canvases from medieval mosaics, all at a huge cost:
Coalitionary proactive aggression is responsible for execution, war, massacre, slavery, hazing, ritual sacrifice, torture, lynchings, gang wars, political purges, and similar abuses of power…It permits sovereignty as a right over life, caste as a system of casual domination, and guards who make prisoners dig their own graves. It makes kings of wimps, underlies fidelity to groups, and gives us long-term tyrannies. It has battered our species since the Pleistocene.
Wrangham is quick to point out a silver lining: “It is therefore cheering to remember that in sane individuals proactive aggression is a highly selective behavior that is delicate attuned to context.” From classrooms to police to law courts we have checks on proactive aggression, as imperfect as they often are.
War and violence may be as part and parcel of our brains as cerebellums and amygdalae, but Wrangham eschews pure biological determinism. And here’s the crux of The Goodness Paradox. Unlike marquee neurobiologists such as David Eagleman and Robert M. Sapolsky, who dismiss free will as a fallacy, Wrangham affirms our conscious choices, which work in tandem with the trapeze wires of our unconscious. “From hunter-gatherers to the Pope,” he observes, “we all live by a moral compass.” We log long hours in labs, pursuing cures for diseases. We volunteer for charitable causes and (usually) break up fights on the playground. We acknowledge neurobiological complexity as it plays out in real time: consider the unusual incident as the Lincoln Memorial earlier this year, when the immature frontal cortices of adolescent boys crashed into the systemic oppression of Native peoples, personified by the Covington Catholic students and Nathan Phillips.
For all of our country’s flash points, the era of Trump has been a boon for “big ideas” nonfiction. Nowhere has this been more conspicuous than in the field of popular science: Sapolsky’s Behave, The Poison Squad by Deborah Blum, Carl Zimmer’s She Has Her Mother’s Laugh, and The Tangled Tree by David Quammen, have all been published since he took office. Despite its donnish opening act, The Goodness Paradox joins their ranks, serving up arresting arguments about the biological foundation of morality. As a political faction mounts a ludicrous and irresponsible war on science, we need these books more than ever.