Johnstone Family Professor, Department of Psychology; Harvard University; Author, The Sense of Style
Psychologist, Harvard University; Author, The Blank Slate

The Decline of Violence

In 16th century Paris, a popular form of entertainment was cat-burning, in which a cat was hoisted on a stage and was slowly lowered into a fire. According to the historian Norman Davies, "the spectators, including kings and queens, shrieked with laughter as the animals, howling with pain, were singed, roasted, and finally carbonized."

As horrific as present-day events are, such sadism would be unthinkable today in most of the world. This is just one example of the most important and under appreciated trend in the history of our species: the decline of violence. Cruelty as popular entertainment, human sacrifice to indulge superstition, slavery as a labor-saving device, genocide for convenience, torture and mutilation as routine forms of punishment, execution for trivial crimes and misdemeanors, assassination as a means of political succession, pogroms as an outlet for frustration, and homicide as the major means of conflict resolution—all were unexceptionable features of life for most of human history. Yet today they are statistically rare in the West, less common elsewhere than they used to be, and widely condemned when they do occur.

Most people, sickened by the headlines and the bloody history of the twentieth century, find this claim incredible. Yet as far as I know, every systematic attempt to document the prevalence of violence over centuries and millennia (and, for that matter, the past fifty years), particularly in the West, has shown that the overall trend is downward (though of course with many zigzags). The most thorough is James Payne’s The History of Force; other studies include Lawrence Keeley’s War Before Civilization, Martin Daly & Margo Wilson’s Homicide, Donald Horowitz’s The Deadly Ethnic Riot, Robert Wright’s Nonzero, Peter Singer’s The Expanding Circle, Stephen Leblanc’s Constant Battles, and surveys of the ethnographic and archeological record by Bruce Knauft and Philip Walker.

Anyone who doubts this by pointing to residues of force in America (capital punishment in Texas, Abu Ghraib, sex slavery in immigrant groups, and so on) misses two key points. One is that statistically, the prevalence of these practices is almost certainly a tiny fraction of what it was in centuries past. The other is that these practices are, to varying degrees, hidden, illegal, condemned, or at the very least (as in the case of capital punishment) intensely controversial. In the past, they were no big deal. Even the mass murders of the twentieth century in Europe, China, and the Soviet Union probably killed a smaller proportion of the population than a typical hunter-gatherer feud or biblical conquest. The world’s population has exploded, and wars and killings are scrutinized and documented, so we are more aware of violence, even when it may be statistically less extensive.

What went right? No one knows, possibly because we have been asking the wrong question—"Why is there war?" instead of “Why is there peace?" There have been some suggestions, all unproven. Perhaps the gradual perfecting of a democratic Leviathan—"a common power to keep [men] in awe"—has removed the incentive to do it to them before they do it to us. Payne suggests that it’s because for many people, life has become longer and less awful—when pain, tragedy, and early death are expected features of one’s own life, one feels fewer compunctions about inflicting them on others. Wright points to technologies that enhance networks of reciprocity and trade, which make other people more valuable alive than dead. Singer attributes it to the inexorable logic of the golden rule: the more one knows and thinks, the harder it is to privilege one’s own interests over those of other sentient beings. Perhaps this is amplified by cosmopolitanism, in which history, journalism, memoir, and realistic fiction make the inner lives of other people, and the contingent nature of one’s own station, more palpable—the feeling that "there but for fortune go I."

My optimism lies in the hope that the decline of force over the centuries is a real phenomenon, that is the product of systematic forces that will continue to operate, and that we can identify those forces and perhaps concentrate and bottle them.