In his 2011 book The Better Angels of Our Nature: Why Violence Has Declined, Harvard University psychologist and famed intellect Steven Pinker argues humans are now living in the most peaceful era in the history of our species.
At the time the U.S. was mired in two wars in the Middle East and Central Asia, the conflict in Darfur had just come to a close and terrorist insurgent group Boko Haram was setting off bombs across northern Nigeria. Such examples still abound years later. Last week violent incidents in New York City and Sutherland Springs, Texas, left many dead and injured. “The claim that we are living in an unusually peaceful time may strike you as somewhere between hallucinatory and obscene,” Pinker wrote. “I know from conversations and survey data that most people refuse to believe it.”
Yet there is plenty of evidence supporting Pinker’s claim. Most scholars agree the percentage of people who die violent war-related deaths has plummeted through history; and that proportionally violent deaths decline as populations become increasingly large and organized, or move from “nonstate” status—such as hunter–gatherer societies—to fully fledged “states.”
Still, there are many ways to look at the data—and quantifying the definition of a violent society. A study in Current Anthropology published online October 13 acknowledges the percentage of a population suffering violent war-related deaths—fatalities due to intentional conflict between differing communities—does decrease as a population grows. At the same time, though, the absolute numbers increase more than would be expected from just population growth. In fact, it appears, the data suggest, the overall battle-death toll in modern organized societies is exponentially higher than in hunter–gatherer societies surveyed during the past 200 years.
The study—led by anthropologists Dean Falk at The Florida State University and Charles Hildebolt at Washington University in Saint Louis—cut across cultures and species and compared annual war deaths for 11 chimpanzee communities, 24 hunter–gatherer or other nonstate groups and 19 and 22 countries that fought in World Wars I and II, respectively. Overall, the authors’ analysis shows the larger the population of a group of chimps, the lower their rate of annual deaths due to conflict. This, according to the authors, was not the case in human populations. People, their data show, have evolved to be more violent than chimps. And, despite high rates of violent death in comparison with population size, nonstate groups are on average no more or less violent than those living in organized societies.
Falk and Hildebolt point out Pinker’s claims are based on data looking at violent death rates per 100,000 people. They contend such ratios don’t take into account how overall population size alters war death tallies—in other words how those ratios change as a population grows, which their findings do. There is a strong trend for larger societies to lose smaller percentages of their members to war, Falk says, but the actual number of war deaths increases with growing population sizes. “This is not what one would predict if larger societies were less violent than smaller ones,” she says. Falk adds that small communities are not necessarily more violent than larger populations—they are simply more vulnerable to losing a significant portion of their population due to outsider attacks. “If I walk down a dark alley at night, I am potentially more vulnerable to being killed than I am when I attend a football game,” Falk says. She admits citing a population of one in an alley is an extreme example. But she adds that smaller populations suffering a higher percentage of casualties at the hands of another population are not necessarily more innately violent than large modern societies are—they might instead just be the victims.
The outsize rise in total war-related deaths associated with larger groups of people may be due, in part, to the advances in weaponry and military strategy that come with increased communication and collaboration: A similar degree of violent behavior enacted by a similar number of people just does more damage on a nuclear scale than it ever could with axes and spears.
For his part, Pinker disputes the new findings. “The claim that the difference between [chimp] death rates can explain the difference in [absolute] death rates between the New Guinean Dugum and Nazi Germany or the difference between [the] U.S.S.R. and India in World War II falls into this category of mindless curve-fitting,” he commented to Scientific American, referring to the study’s data on absolute numbers of deaths and the fact cultural and geographical factors can greatly sway war-death totals in individual populations. “Presumably the fact that Hitler invaded the Soviet Union whereas India was thousands of miles away from the major theaters of war has more to do with that difference than their population size!”
He also argues the authors exaggerate what they describe as “exponential” growth in deaths among large populations, given that their data shows the average war deaths during World Wars I and II—and surveyed across the last two centuries of data for nonstate groups—did not rise all that significantly as populations grew, and differ wildly among populations. He goes so far as to say the authors “misdescribe their own data,” noting their numbers suggest total deaths during World War I actually decreased with increasing population size. “Using that average to conclude that humans are more violent than chimps and that war deaths scale exponentially with population size is going way beyond what the data can support,” says Pinker.
Pinker points out many anthropologists are committed to some version of the noble savage theory—the idea that in the wild humans are innately good, only to be corrupted by society and civilization. Falk acknowledges this, in part, motivated her to undertake the study. “As anthropologists we were primarily concerned about the negative portrayal of small-scale societies as more violent than “civilized” state dwellers.”
Yet Falk and Hildebolt do not believe any bias skewed their results. “We had no expectations regarding absolute number of war deaths and population sizes, and we were indeed surprised by the [results],” Falk says.”
In The Better Angels of Our Nature Pinker wrote our cognitive faculties predispose us to believe we live in violent times—and modern media does not help: As he puts it, “If it bleeds, it leads.” Our tendency is to broadcast negativity. We only leave Yelp reviews when our steak was overcooked. We leave comments online when we are outraged, not enlightened. And we typically approximate the probability of something happening based on when we last witnessed it. Pinker believes that even in times of very low violent deaths there will always be enough such incidents for the media to exploit; enough to warp our sense of the reality.
It may be too early to say exactly how our new hyper-connected culture will influence rates of violent mortality. Does increased awareness and exposure to the world’s wrongs via a 24-hour global news cycle render us wearier of violence or more empathetic to the victimized? Or do horrific and continual mass killings in turn incite more copycat violence?
Pinker cites a number of trends through history he feels support the idea that despite the seemingly continual carnage in the world, we have actually inched toward a more civil society. Our transition from hunter–gatherers to farmers is thought to have reduced violent death fivefold; between the Middle Ages and the 20th century, Europe saw a 10- to 50-fold drop in murder; and in the 70-plus years since World War II warring among the leading powers has for the most part stopped, a first in the history of civilization.
None of this gives Falk much comfort when it comes to mass-scale war and mortality, given that modern weaponry can inflict sky-high total death counts. Astronomical death tolls can be tallied in a matter of days, even minutes, not decades. “All it would take is for one homicidal leader—who we know exists—to unleash a weapon of mass destruction,” she warns. “The 70-odd years that have transpired since World War II is a proverbial drop in the bucket compared with the five [million] to seven million years humans and our ancestors have been around. The probability of World War III is not negligible.”