I recently visited Caquetá, one of the southernmost regions of Colombia, noted for its beautiful Amazonian landscape and its bitter armed conflict. For almost five decades, it has been the epicenter of violent confrontations between a long list of regular and irregular armed groups, with a frighteningly high murder rate and periodic civilian massacres the result. As a health worker in the region who deals with the consequences of violent conflict, I could not help feeling a touch of irony as I read Steven Pinker’s new book, 

, which examines how “the decline of violence may be the most significant and least appreciated development in the history of our species.”

Pinker, a psychologist and linguist at Harvard, is best known for his books about cognitive science, but in 

 he has produced an excellent exploration of how and why violence, aggression, and war have declined markedly, to the point where we live in humanity’s most peaceful age. This news is likely to come as a surprise to many, who are perhaps more familiar with the specters of industrial warfare, nuclear Armageddon, and nightly televised atrocities, but Pinker musters an impressive array of evidence—his book contains more than a hundred maps and graphs, including data illustrating the falling homicide rates in Western Europe over the past several centuries and a chart showing the dramatic increase in the number of apologies by political and religious leaders in the last few decades—to demonstrate that, since early history, violence has become less and less a fact of everyday life.

The Greek epics and the Old and New Testaments are full of accounts of horrific personal and mass violence—gruesome battles, genocides, stonings, crucifixions. During the Middle Ages, knights vied for power by fighting for control of land and the human property that lived on it. Mutilation and torture were not just the standard punishments for an array of minor crimes, actual or imagined, but also a major source of public entertainment that was as inventive as it was vile. Intercommunity and interpersonal violence was a primary cause of death, while physical abuse of women and children was not only accepted but expected.

Since those dark times, history has seen a steady decline in death and brutality. Even taking into account the extremity of the 20th century’s world wars, genocides (including the Holocaust), ethnic cleansing campaigns, and war-related diseases and famines, which marked a genuine uptick in the otherwise downward historical trend in the rate of violent death, a conservative estimate puts deaths from these human causes at just three percent of the deaths in the 20th century. In prehistoric hunter- gather societies, Pinker observes, roughly 15 percent of people came to violent ends. Several conflicts of the distant past took a proportionately greater toll on the global population than the world wars, including the Mongol conquests of the 13th century and the An Lushan Revolt in the eighth century during China’s Tang dynasty, in which 36 million people (two-thirds of the Chinese Empire’s population) died. Pinker notes that the decline in violence is evident not only in wars but in almost every sphere of unpleasantness—slavery, inhumane treatment of criminals, hate crimes, homicide, sexual abuse, even the treatment of animals.

Sociologist Norbert Elias called this movement toward restraint the civilizing process. (Pinker is clearly a fan of Elias’s work.) 

 identifies several historical trends that have helped humanity reach its state of relative modern peace. The growth of the state, with its monopoly on violence and its ability to curb vengeance through the administration of justice that is disinterested in personal feuds, correlates with a reduction in murder rates wherever national boundaries have appeared. Commerce has huge potential to provide benefits to both parties in an economic exchange and promotes mutual cooperation even when differences emerge. The idea that personal well-being and freedom from suffering are important social values in themselves became a major influence in the Enlightenment and remains a cultural cornerstone to the present day. It lives on in the modern concept of human rights. Less recognized but accorded equal value in Pinker’s book is the process of feminization, whereby the acceptance of female-friendly values (including ready access to birth control and “the deflation of manly honor,” which has a tendency to start fights) reliably leads to less violent societies.

Perhaps less convincing is Pinker’s discussion of how our minds and brains have adapted to reduce the psychological payoffs for violence. We really know very little about the psychology and neuroscience of personal violence, not least because getting people to batter each other in the lab has never been popular with academics, while few potential killers are interested in doing a short test involving attention and problem solving before they take up arms. More seriously, violence is predicated on the intent to do harm and injury, yet ethical research demands that harm and injury be avoided, and so studies of violence tend to follow subjects who are naturally aggressive or else use watered-down games in the lab in which participants can do no more than express their hostility through mild punishments.

One of the best-known researchers on the neuroscience of aggression is Estonian-born psychologist and neuroscientist Jaak Panksepp, who has identified several primary emotion circuits in small mammals such as mice and cats, including one he calls the “Rage circuit,” which, when stimulated, produces an immediate aggressive response. Although a little too Freudian for some, Panksepp has made a massive contribution to our understanding of emotion; still, his concept of a specific rage circuit is not widely accepted by either animal or human neuroscientists. You wouldn’t know that, however, from reading Pinker’s book.

This overreliance on Panksepp’s work makes for a great narrative but only a partial view of how the brain generates hostile impulses, and Pinker is left making sweeping generalizations. For instance, he writes that “all the parts of the rat brain have been carried over to the human brain, including the organs that house the circuits for rage, fear, and dominance,” then launches into a discussion of the science of the human brain as if nothing out of the ordinary has just been proposed. The current understanding of how the limbic system and other deep brain structures (which are by no means dedicated to hostility) are involved in the motivation to attack and how these motivations are kept in check by brain networks in the frontal lobes (which Pinker does address well) is no less interesting than the limited version presented in the book.

I suspect that Pinker’s preference for the “we have inherited it from rats” explanation of aggressive urges may have been encouraged by his well-known objection to “blank slateism” (the subject of one of his earlier books), a theory popular among many intellectuals in which genetic influences are played down to the point of assuming that all of our thoughts and behavior result purely from our experiences during life. Although the genetic data is not always cut and dried, Pinker has done an admirable job of alerting us to how the effect of the environment is often vastly exaggerated, but occasionally his evangelical spirit itself leads to exaggeration. In one section, he writes that “by the late 20th century, the idea that parents can harm their children by abusing and neglecting them (which is true) grew into the idea that parents can mold their children’s intelligence, personalities, social skills, and mental disorders (which is not).” While the inclusion of each of these categories is controversial, the appearance of mental disorders on this list only makes sense if you throw out years of research on how childhood treatment can alter the risk of mental illness, along with, as it happens, adult aggression and violence.

I found equally unconvincing Pinker’s argument about how violence declines as IQ levels rise and how this reflects the moderating effect of reason on aggression. Intelligence can equally be applied to justifying nonsense as to debunking it, and problem solving is not the same as evidence-based skepticism, but there is not a hint of dishonesty in the book. Pinker dismisses as many attractive theories as he accepts. For example, the appealing idea that violent people are more likely to have a specific version of the gene for monoamine oxidase, an enzyme that breaks down neurotransmitters such as serotonin in the brain, is rightly given short shrift despite the fact that it is a pop-science favorite.

For a book championing humanity’s unrecognized triumph over violence, 

 also includes some interesting reflections on whether the culture of nonviolence has gone too far in some respects, to the point where children are being prevented from playing sports such as dodge ball due to these games’ aggressive nature. This trend can also be seen in how the concept of violence is used to stigmatize other unwanted behaviors—for example, what was traditionally called “verbal abuse” is now being increasingly categorized and condemned as a form of “psychological violence.”

This is not to say that our work is done and we can rest on our peaceful laurels. Brutality is still endemic throughout the world, but the fact that we have gotten to the stage where violence is considered abnormal and unnecessary is, historically, an astounding transformation. One of Pinker’s more subtle observations about how this peaceful revolution is reflected in society is that war memorials have changed in the last hundred years from being celebrations of glory and triumph to laments for lost lives.

Despite my concerns about how Pinker portrays individual psychology and neuroscience, 

 is so comprehensive that these faults represent only a fraction of the book. Taken as a whole, it is powerful, mind changing, and important. Pinker does not shy away from the gritty detail and is not to be taken lightly—quite literally in fact, as at more than 800 pages his book could easily be used as a weapon if you remained unpersuaded by its arguments. But this avalanche of information serves to demonstrate convincingly and counterintuitively that violence is on the decline.

In many ways, violence is a disease of the emotions. While we should never ignore the victims, it can be managed and curbed so it affects as few people as possible and remains minimally contagious. Many illnesses that once felled multitudes are now largely vanquished through greater knowledge and simple preventive measures; a similar process has made us all less likely to be targets, and perpetrators, of brutality. As Pinker argues, this is an achievement we should take pride in.

 is currently working for Médecins Sans Frontières (Doctors Without Borders) as mental health coordinator for Colombia. He is an honorary research fellow at the Institute of Psychiatry, King’s College London, and is writing a book, 

The Enchanted Window: How Hallucinations Reveal the Hidden Workings of the Mind and Brain.

The Better Angels of Our Nature: Why Violence Has Declined

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Brutality is still endemic, but the fact that we have gotten to the stage where violence is considered unnecessary is, historically, an astounding transformation.

Vaughan Bell