Steven Pinker, a professor of psychology at Harvard University, is the author of the best-selling books, “How the Mind Works,” and “The Blank Slate.” But he is also a public intellectual, devoted to bringing the ideas of academia to questions of broad public interest. His latest work is an ambitious attempt to understand the origins, history—and perhaps the future—of human violence. The book is called “The Better Angels of Our Nature: Why Violence Has Declined,” and it combines science with history to conclude that, by many measures, we live in the best of times, not the worst. He spoke recently with Mind Matters editor Gareth Cook.

COOK: What would you say is the biggest misconception people have about violence?

PINKER: That we are living in a violent age. The statistics suggest that this may be the most peaceable time in our species’s existence.

COOK: Can you give a sense for how violent life was 500 or 1000 years ago?

PINKER: Statistics aside, accounts of daily life in medieval and early modern Europe reveal a society soaked in blood and gore. Medieval knights—whom today we would call warlords—fought their numerous private wars with a single strategy: kill as many of the opposing knight’s peasants as possible. Religious instruction included prurient descriptions of how the saints of both sexes were tortured and mutilated in ingenious ways. Corpses broken on the wheel, hanging from gibbets, or rotting in iron cages where the sinner had been left to die of exposure and starvation were a common part of the landscape. For entertainment, one could nail a cat to a post and try to head-butt it to death, or watch a political prisoner get drawn and quartered, which is to say partly strangled, disemboweled, and castrated before being decapitated. So many people had their noses cut off in private disputes that medical textbooks had procedures that were alleged to grow them back.

COOK: What made you interested in violence as a scientific question?

PINKER: I’ve long argued that the human mind is not a blank slate but has been fitted by evolution with a complex set of emotions, drives, and systems for reasoning, learning, and communicating. Advocates of the blank slate fear that the very idea of human nature dooms us to perpetual conflict—that if we are killer apes with a territorial imperative, a thirst for blood, a death instinct, and genes for aggression, then it’s pointless to try to make the world a better place.

These fears, I’ve argued, are illogical. Human nature may embrace motives that lead to aggression, but it also embraces motives like empathy, self-control, and reason, which, under the right circumstances, can outweigh the aggressive impulses.

And empirically, we can observe many ways in which violence has decreased over time, including a relief from cycles of deadly raiding and feuding when tribes came under the control of states, the 35-fold decline of homicide in medieval Europe, the abolition of slavery, cruel punishments, and frivolous executions, and the recent replacement of totalitarian regimes with democracies. These observations amounted to a few paragraphs in “How the Mind Works”and “The Blank Slate,” but I knew when writing them that they really deserved a book of their own.

COOK: How has neuroscience contributed to our understanding of violence and its origins?

PINKER: Neuroscientists have long known that aggression in animals is not a unitary phenomenon driven by a single hormone or center. When they stimulate one part of the brain of a cat, it will lunge for the experimenter in a hissing, fangs-out rage; when they stimulate another, it will silently stalk a hallucinatory mouse. Still another circuit primes a male cat for a hostile confrontation with another male. Similar systems for rage, predatory seeking, and male-male aggression may be found in Homo sapiens, together with uniquely human, cognitively-driven systems of aggression such as political and religious ideologies and moralistic punishment. Today, even the uniquely human systems can be investigated using functional neuroimaging. So neuroscience has given us the crucial starting point in understanding violence, namely that it is not a single thing. And it has helped us to discover biologically realistic taxonomies of the major motives for violence.

COOK: You discuss in detail the "long peace," the period of calm in Europe after World War II. What do you conclude has been behind this—and what do you conclude has not been an important factor?

PINKER: Some people believe that the nuclear bomb should be awarded the Nobel Peace Prize, since it scared the major powers away from war by equating it with doomsday. But there are reasons to be skeptical. One is that World War II proved that conventional warfare in modern times was already plenty destructive. The fear of conventional World-War-II-style war would have been enough to scare the major powers away from a repeat performance. Another is that nuclear weapons have, fortunately, acquired such an apocalyptic aura that the threat is seen more as a bluff than a deterrent, which is why non-nuclear powers have repeatedly defied the nuclear ones (Argentina vs. Britain in 1982, Egypt vs. Israel in 1973, Iraq vs. the US in 1991 and 2003, and so on).

Better candidates include conventional deterrence, the spread of democracy, the expansion of international trade, the growth of international organizations, and the gradual eclipsing of the value of national and ethnic grandeur by the value of human rights—a hard-won lesson of the two world wars.

COOK: Does your reading of the scientific literature suggest ways that societies can drive violence down even further? Are there any specific strategies that you think have not received enough attention?

PINKER: Policy is a subject best left to policy analysts, since the devil is in the details, but there are a few general forces that seem to work across times and places. Decent government helps, particularly non-corrupt, non-brutal, and consistent policing. Halfway decent governments also provide basic services like education (which gives young men an alternative to adventure in militias) and an infrastructure of commerce (which tips the incentives from zero-sum plunder to positive-sum trade). In the international arena, peacekeepers are demonstrably effective—not 100 percent of the time, but more often than when adversaries are left to fight to the bitter end.

More nebulously, the forces of cosmopolitanism—literacy, travel, journalism, education, the mixing of peoples—corrodes tribalism, authoritarianism, and puritanism, with all the punitive sentiments that go with them, and make it harder to demonize foreigners and nonconformists. Intellectuals, for their part, should avoid the thrills of utopian, group-exalting, and struggle-glorifying ideologies, and promote incremental and evidence-based improvements that put the flourishing of individuals first.

COOK: Is the general trend toward less violence going to continue in the future?

PINKER: It depends. In the arena of custom and institutional practices, it’s a good bet. I suspect that violence against women, the criminalization of homosexuality, the use of capital punishment, the callous treatment of animals on farms, corporal punishment of children, and other violent social practices will continue to decline, based on the fact that worldwide moralistic shaming movements in the past (such as those against slavery, whaling, piracy, and punitive torture) have been effective over long stretches of time. I also don’t expect war between developed countries to make a comeback any time soon. But civil wars, terrorist acts, government repression, and genocides in backward parts of the world are simply too capricious to allow predictions. With six billion people in the world, there’s no predicting what some cunning fanatic or narcissistic despot might do.

COOK: Having worked through this material, I wonder, do you see current events differently now?

PINKER: Absolutely. The present looks less sinister, the past less innocent. The mind always focuses on current threats, and takes for granted the violent events that don’t happen but could easily have happened a few decades ago. A sniper in Norway kills dozens of innocent people—and the population does not riot or lynch the perpetrator and his extended family, but holds candlelight vigils. The Egyptian government falls—but the new one does not vow to push the Israelis into the sea. North Korea sinks a South Korean ship, killing 45 sailors—but instead of escalating to war, the Koreans go back to life as usual. Every day I notice the dogs that don’t bark.

Are you a scientist who specializes in neuroscience, cognitive science, or psychology? And have you read a recent peer-reviewed paper that you would like to write about? Please send suggestions to Mind Matters editor Gareth Cook, a Pulitzer prize-winning journalist at the Boston Globe. He can be reached at garethideas AT gmail.com or Twitter @garethideas.