Shocker: Is Our World Becoming Less Violent?

Many believe the 20th century represents the pinnacle of human violence, but psychologist Steven Pinker argues that the opposite is true.

Humanity's lust for violence has undergone a long, precipitous decline at every level of social interaction, from domestic abuse to violent crime to interstate wars. That's the sweeping and somewhat counterintuitive thesis of psychologist Steven Pinker's new book, The Better Angels of Our Nature: Why Violence Has Declined. The pacification of humanity, says Pinker, is “a fractal phenomenon, visible at the scale of millennia, centuries, decades, and years.”

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Pinker writes that the “very idea invites skepticism, incredulity and sometimes anger.” He sets out to overcome that barrier by surveying a broad swath of data, from examinations of ancient bones unearthed in peat bogs and on long-forgotten battlefields, to homicide statistics based on European coroners' inquests and local records dating back 800 years, to databases of modern interstate conflicts and civil wars.

Does Pinker's research validate his thesis? And if so, what forces might explain such a profound shift in human society?

Are We Really Less Violent Today?

Pinker makes his case by combing dozens of disparate datasets to pull out what he proposes is a standard measure of our tendency toward violence: the likelihood of dying at the hand of another human being in a given year. In the long sweep of human history, he makes a compelling case, noting that almost 20 percent of bones uncovered at archaeological excavations of prehistoric societies show evidence of violent trauma – a death rate unparalleled in even the bloodiest episodes in recent history.

With the emergence of the city-state – first in pre-Columbian Mexico in the 15th century -- the rate of violent death declines precipitously, to 5 percent. Wandering closer to modernity, Pinker cites estimates of war deaths (excluding violent crime) in the two most violent regions and centuries of the era of the nation-state: 17th century Europe, “with its bloody wars of religion,” and the 20th century, with its two world wars. Historian Quincy Wright estimated the 17th century death-rate by war at 2 percent, and estimates of that measure in the 20th century run as “low” as 1 percent.

He cites criminologist Manuel Eisner's study of homicides in Europe dating back to 1200 CE, which illsutrated an equally dramatic decline in one-on-one violence, at least on the continent. Eisner estimates that during the Middle Ages, about 100 in 100,000 people were murdered, a figure that has fallen to around 1 in 100,000 today.

That's but a small a fraction of the research Pinker cites, devoting six chapters brimming with graphics and charts to make his case. Yet, as with any thesis spanning the entire history of human existence planet-wide, Pinker ultimately runs into an empirical wall; there isn't sufficient data to justify the claim that violence has fallen precipitously in every culture and at every level of human interaction throughout history. A comprehensive database of violent deaths worldwide for the 20th century, much less for the 11th, simply does not exist.

Elizabeth Kolbert, reviewing the book for the New Yorker ($$), unfairly charges that “Pinker’s attention is almost entirely confined to Western Europe.” He examines what research is available from a host of societies at different points in history, but he does devote an inordinate amount of space to the decline in violence in the “West,” and in the era of the nation-state, and one might imagine that to be a result of where the best data are to be found.

One also has to question the rigor behind Pinker's contention on the interpersonal level. He can demonstrate that corporal punishment has declined in schools around the world, and show that violent crime has seen a dramatic, decades-long fall in the West, but what about the kind of violence that isn't tracked by governments with any consistency? Has there really been a consistent and global decline in drunken men punching one another in the face? Have we really become more tame at every level of intercourse, and is it really a “fractal” phenomenon that holds true “at the scale of millennia, centuries, decades, and years”?

Pinker himself acknowledges that the decline of violence does not track in a straight line, that it is a historical current with “eddies” of increased violence at various times and in various regions. He notes, for example, that the homicide rate in the United States didn't decline at all in the 20th century; rather it oscillated, rising during the first three decades, falling precipitously by mid-century and then spiking to a high in the 1980s before coming back down to what it was in 1900. (According to the Associated Press, in 2010, homicide fell off of the list of the top 15 causes of death in the United States for the first time since 1965, bumped by an unenviable death by choking on one's food or vomitus.)

But while Pinker doesn't present a slam-dunk, irrefutable case, one might conclude that he's a victim of his own ambition. The sheer weight of his data suggests that his thesis is correct when it comes to the big picture. The historical transition from bands of hunter-gatherers to agricultural societies that formed the basis of city-states to the emergence of early feudal states and finally the birth of the modern nation-state does correlate rather neatly with a precipitous decline in intra- and inter-communal violence.

Bringing Forth the 'Better Angels of Our Nature'

This leads to a question of why, as Pinker puts it, it has become a cliché that “the twentieth century was the bloodiest in history”? He attributes this widespread belief to “historical amnesia,” a cognitive tendency to “overweight the conflicts that are most recent, most studied or most sermonized.” He demonstrated this by asking 100 people (presumably Americans) to write down as many wars as they could recall in five minutes, an exercise that produced results that were heavily “weighted toward the world wars, wars fought by the United States and wars close to the present.”

We also tend to believe the 20th century to be the most violent because of advances in the technology of destruction. It is only in recent history that we have had the capacity to incinerate 80,000 people in an instant in Hiroshima, and many millions with modern nuclear ICBMs. The overall number of war-deaths in the last century did represent a historic high. But here, again, we have to return to Pinker's unifying metric of violence: violent death proportional to the entire population. There were many more humans walking the planet in the 20th century than there were in the eighth century.

When Pinker adjusts for population size, it becomes clear that the two world wars that marked the crescendo of interstate violence in absolute numbers were anything but exceptional in relative terms. About 15 million people perished during World War I, and 55 million more died in World War II. But the Mongol invasions of the 13th century resulted in an estimated 40 million war deaths, a figure that would represent 278 million people relative to the human population in the middle of the 20th century. In China, the Lushan Rebellion killed 36 million people in the eighth century, a death toll that would total 429 million -- or six times the combined carnage of the two world wars -- relative to the human population during World War II. 

Pinker is on his most solid ground arguing that we hold an idealized view of an earlier, more tranquil era in human history. He explicates, often in gruesome detail, the bloody history of human society prior to the age of enlightenment (to which we'll return presently). That long epoch played out against “a backdrop of violence that was endured, and often embraced, in ways that startle the sensibilities of a 21st century Westerner.”

Indeed, we recoil at the idea of civilian casualties -- “collateral damage” -- incurred during conflicts today, but in Biblical times, genocidal wars that wiped entire populations off the earth were a relatively common “extension of policy by other means,” as the military theorist Karl von Clausewitz put it.

Tales of torture by authoritarian regimes shock the conscience today, but the most gruesome forms of torture weren't only routine in the Middle Ages, they were often a source of entertainment – people laughed at the degradation and abuse of their fellow humans. That rulers weren't free to slaughter their own citizens is only a relatively recent concept; that communal lynching is abhorrent an even more recent advent. And today, humans' revulsion to physical violence extends not only to other humans, but to animals as well. Pinker takes readers on a horrifying tour of the unvarnished history of violence, pausing to point out sites like human sacrifice, inquisitions and witch-hunts along the way.

In prehistoric societies, hunter-gatherers lived lives of almost constant tribal warfare. Bands raided their neighbors for three primary reasons, Pinker argues, and these grounds persist in some form in modern conflicts: attacks inspired by competition for scarce resources; preemptive strikes, out of fear that a group would be raided if it didn't move first; and raids to avenge past attacks in the hope of deterring future aggression.

It is when he explicates this long and profound decline in organized violence over a larger scale of human history – spanning millennia rather than decades – that Pinker is most convincing. Which leads to the question of what we might credit for the decline – what it is precisely that brought forth the “better angels of our nature.” Pinker offers several possible explanations for what he calls a long “civilizing process.”

First and foremost is the emergence of the nation-state. Pinker argues that the constant raiding that marked hunter-gatherer societies validated the enlightenment philosopher Thomas Hobbes' view of humanity in a state of nature – a world in which life was typically “nasty, brutish and short.” In Hobbes' formulation, the state serves as an all-powerful “leviathan” that holds a monopoly on the legal use of violence, and, in turn, defuses the primary motives for inter-communal violence: it deters aggressive attacks for resources, which in turn lessens the need for preemptive attacks as well as the urge to avenge every slight as a form of deterrence.

Pinker cites a study of 27 non-state societies and compared their average death rate due to wars with that of one of the most violent states in history, the Aztec Empire of Central Mexico, and found that those living in the average non-state society were twice as likely to perish in battle. Although the data is somewhat limited, he demonstrates that the same holds true in terms of homicides.

But the emergence of states isn't enough to explain the decline. In their earliest iteration, states were feudal fiefdoms and fractured monarchies under despotic rule. Leaders thought of their subjects as little more than cannon-fodder, materiel to be exchanged for glory, God or territory. “The first leviathans,” writes Pinker, “solved one problem but created another. [People] were less likely to become the victims of homicide or casualties of war, but they were now under the thumbs of tyrants, clerics and kleptocrats.” Solving this problem, he argues, would “have to wait another few millennia, and in much of the world it remains unsolved to this day.”

Pinker puts a great deal of weight on the Enlightenment period in his civilizing process. Exhausted by almost three centuries of gruesome religious wars, Western thinkers underwent an “intellectual and moral change: a shift from valuing souls to valuing lives.” Pinker notes that while territory and “dynastic power” were at stake, “religious differences kept tempers at a fever pitch” in Europe between the early 16th century and the mid-17th century. It was an era in which the whole schema of human society underwent dramatic changes in a relatively short period. “The calming of religious fervor meant that wars were no longer inflamed with eschatological meaning, so leaders could cut deals rather than fight to the last man,” writes Pinker. “Popular writers were deconstructing honor, equating war with murder, ridiculing Europe's history of violence, and taking the viewpoints of soldiers and conquered peoples.”

It was during the Enlightenment that, “in the span of just over a century, cruel practices that had been a part of civilization for millennia were suddenly abolished.” 

The Killing of witches, the torture of prisoners, the persecution of heretics, the execution of non-conformers, and the enslavement of foreigners – all carried out with stomach-turning cruelty – quickly passed from the unexceptional to the unthinkable.

This was one of two “human rights revolutions” -- the other being the post-World War II advances in international law that followed the Nuremberg Tribunals and culminated in the signing of the United Nations' treaty. That process has continued into this century with a shift from an unwavering emphasis on state sovereignty – with the “right” of governments to manage their own domestic affairs as they see fit -- to what has come to be known as the international community's “responsibility to protect” the lives of innocents.

Another factor contributing to the decline of violence, Pinker argues, is that technology, and the emergence of the modern nation-state, enabled a dramatic increase in “non-zero-sum” transactions between different communities and states. Commercial trade, specifically, has been seen as a disincentive to violence since Immanuel Kant wrote Perpetual Peace: a Philosophical Sketch in the late 18th century.

Pinker also cites a theory proposed by philosopher Peter Singer in his book The Expanding Circle. Singer suggests that human beings have an inherent capacity for empathy; that the ability to identify and cooperate with others conferred an evolutionary advantage on early homo sapiens. But that empathy was, throughout much of our history, limited to a small circle of people: the extended family, the clan. Those residing outside of the circle have often been seen as less than human, and treated accordingly. But with the decline in violence, that circle of humans whose lives we deem worthy of our respect (Pinker says it should be called the “circle of sympathy”) has expanded, from the village to the tribe to the nation-state. And it has continued to expand to people of different ethnicities and religions and sexual orientations, to those who were once dispatched with impunity. (Singer deploys this theory in service of an argument for according the same rights to other sentient species.)

Why that circle has expanded is unclear. Pinker writes that he uses the “expanding circle” as “a name for the historical process in which increased opportunities for perspective-taking led to sympathy for more diverse groups of people.” He cites the advent of the printing press and popularization of the novel, a medium that allowed people to imagine themselves inside the heads of other people for the first time. He posits that advances in personal hygiene made others less repulsive, and therefore harder to see as subhuman. And as economic development and scientific advances extended human life, it simply became dearer, and more valuable. When life really was “nasty, brutish and short,” it was far easier to take a life without remorse.

More recently, Pinker talks about the role played by women entering the public sphere. For him, the “feminization” of society isn't a cultural problem, but a profound public good. “Historically,” he writes, “women have taken the leadership in pacifist and humanitarian movements out of proportion to their influence in other political institutions...and recent decades, in which women and their interests have had an unprecedented influence in all walks of life, are also the decades in which wars between developed states became increasingly unthinkable.”

Having marshaled his evidence, Pinker turns in his final chapter to the question of whether the decline in violence is a phenomenon that is likely to persist. Pinker considers himself a cautious optimist, but is not a historical determinist. “Optimism,” he writes, requires a touch of arrogance, as it extrapolates the past to an uncertain future.”

Having identified “the broad forces that have pushed violence downward,” he can only say that humanity's increasing distaste for blood is “a product of social, cultural and material conditions. If the conditions persist, violence will remain low or decline even further; if they don't, it won't.”

Joshua Holland is an editor and senior writer at AlterNet. He is the author of The 15 Biggest Lies About the Economy: And Everything else the Right Doesn't Want You to Know About Taxes, Jobs and Corporate America. Drop him an email or follow him on Twitter.