The remarkable decline of violence

Many will greet the title of this piece with considerable skepticism — in this day and age how could one possibly talk about a decline in violence? Yet it is true. Harvard psychologist Steven Pinker begins his new book The Better Angels of Our Nature: Why Violence Has Declined as follows:

This book is about what may be the most important thing that has ever happened in human history. Believe it or not – and I know that most people do not – violence has declined over long stretches of time, and today we may be living in the most peaceable era in our species’ existence. The decline, to be sure, has not been smooth; it has not brought violence down to zero; and it is not guaranteed to continue. But it is an unmistakable development, visible on scales from millennia to years, from the waging of wars to the spanking of children.

Pinker is hardly a devout religious believer — his review of biblical violence, for instance, is openly irreverent. But from another point of view, Pinker’s book is deeply inspiring: it is a stunning confirmation of the fundamental good in human nature, a chronicle of how the “better angels of our nature” are slowly overcoming the bad. His work also constitutes a striking refutation of those writers, both from the academic left and the religious right, who have decried our time as irredeemably fallen from the “good old days” (decades, centuries or millennia ago) when the human race was presumably more gentle and civilized.

Pinker’s book is not an easy read. He meticulously documents his claims with extensive charts, graphs and footnotes. He invokes relatively sophisticated concepts such as “power-law distributions” with aplomb. He does not bat an eyelash while describing the revolting instruments of torture and execution used in medieval “Christian” Europe. He documents the violent practices of many native peoples. But he has a clear purpose in all of this: to demonstrate in no uncertain terms the fact that the human society is slowing become more averse to violence. He also attempts to understand this phenomenon, so that we can hasten its progress, although it is clear that he does not have all the answers.

Here are some brief highlights from Pinker’s book:

  1. Ancient primitive societies were hardly the Edenic paradises that they are often pictured to be. Careful analyses of skeletons from archaeological sites have confirmed that roughly 15% of these individuals died a violent death. Among more modern pre-state societies, similar analyses show 25% violent death. By contrast, even in medieval Europe, with the bloody wars of religion in the 17th century, the rate of death was only 2%, and this rate fell to less than 1 percent in the 20th (yes, even counting WWI and WWII).
  2. In a list of the 21 “Worst Things People Have Done to Each Other,” which ranks the wars and massacres with the highest death tolls, the 20th century indeed is well-represented: WWII tops the list, following closely by the Chinese cultural revolution. But when these episodes are normalized by world population at the time, then WWII drops to #9. Number 1 on the normalized list is the little-known 8th century An Lushan Revolt, which resulted in the loss of 2/3 of the Chinese empire’s population.
  3. The “long peace” among major powers since WWII has confounded the predictions of many that large-scale war is inevitable in our time. Pinker emphasizes that perhaps the most interesting post-WWII statistic of all is zero: Zero is the number of times that nuclear weapons have been used in combat; zero is the number of times that the two Cold War superpowers fought each other on the battlefield; zero is the number of times that any of the top 40 great powers have fought each other (since 1953); zero is the number of wars fought between any European nation (prior to this there were an average of two armed conflicts per year going back to at least 1400); zero is the number of developed countries that have expanded their territory by conquering another country; and zero is the number of internationally recognized states that have gone out of existence through conquest.
  4. While the modern world, especially in the West, agonizes over even remote chances of harm to today’s children, for much of human history little ones faced a much greater risk: infanticide. Anthropologist Laila Williamson found until very recently, between 10 and 15 percent of all babies were killed shortly after birth. By contrast, in 2007 just 221 infants were killed in the U.S. out of 4.3 million births, which is a reduction from the historical average by a factor of 2000 to 3000.
  5. The U.S. crime rate rose during the 1960s, 1970s and 1980s until about 1992, but has declined since then. By 2010, the homicide rate had fallen to just 4.8 per 100,000 residents, down by more than a factor of two from its peak. Other measures of violent crime, and even property crime, have followed in unison. In the wake of the 2008-2011 recession, with millions out of work, losing homes and in desperate economic straits, crime rates have fallen even further, confounding criminologists who had predicted sharp increases.
  6. Pinker points out that by today’s standards, even great statesmen of recent history would be considered hopelessly bigoted and violence-happy. Theodore Roosevelt excused the decimation of Native Americans as necessary to prevent the continent from becoming a “game preserve for squalid savages.” Woodrow Wilson blocked black students from Princeton, praised the Ku Klux Klan, and declared that any hyphenated American “carries a dagger that he is ready to plunge into the vitals of this Republic.” Franklin Roosevelt jailed 100,000 U.S. citizens in a concentration camp because they were of the Japanese race. And Winston Churchill declared that the Aryan stock “is bound to triumph,” and that India is “a beastly people with a beastly religion.”

What is behind such changes? One major factor is the rise of large, effective systems of democratic government, which Pinker terms the “Leviathan” effect, named after the title of a book by 17th century philosopher Thomas Hobbes. Others include the Civilizing Effect and the Pacifying Effect, wherein people have begun to see other societies as cooperating partners capable of trade and mutual enrichment, instead of loathsome aliens that must be eliminated. It also seems that society as a whole, perhaps through improved education, is better able to see the world from the eyes of others. Whatever the reason, it is a trend that we should cherish and understand better.

Pinker’s conclusion resonates with both hope and gratitude:

For all the tribulations in our lives, for all the troubles that remain in the world, the decline of violence is an accomplishment we can savor, and an impetus to cherish the forces of civilization and enlightenment that made it possible.

This is also posted at the Math Drudge blog.

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