Last year Steven Pinker, a cognitive scientist at Harvard, published the intriguing book The Better Angels of Our Nature: Why Violence Has Declined. While some of his assumptions and conclusions about the overall decline of violence are questionable, he does seem to be correct about the decline of warfare over the past several decades. Consider this chart, produced by Vox, which shows the decline in deaths attributed to war since the 1940s.

Human nature doesn’t change. With every generation of e the same human problems, such as violence and war. So what accounts for the decline?

Along with violence, another aspect of human nature is that, as economists would say, we respond to incentives. So while we can’t change the violent nature of humanity, we can sometimes change the incentives to promote peace among nations. In an interview withVox’s Zack Beauchamp, Pinker explains that some of thedecline inwar over the past 60 years has been the economic incentives associated with free enterprise:

Zack Beauchamp: One story you hear from political scientists for why there’s been less war recently that it’s just less profitable —countries don’t gain very much, economically or politically, from taking over new land anymore. Does that seem right to you?

Steven Pinker: Yes, it’s one of the causes. It’s the theory of the capitalist peace: when it’s cheaper to buy things than to steal them, people don’t steal them. Also, if other people are more valuable to you alive than dead, you’re less likely to kill them. You don’t kill your customers or your lenders, so the arrival of the infrastructure of trade merce reduces some of the sheer exploitative incentives of conquest.

This is an idea that goes back to the Enlightenment. Adam Smith and Montesquieu extolled it; it was on the minds of the founders when they built incentives for free trade into the Constitution.

I don’t think it’s the entire story of the decline in war. But I do think it’s part of the story. There was a well-known study fromBruce Russett and John Onealshowing statistically that countries that engage in more trade are less likely to get into militarized disputes, and countries that are more integrated into the world economy are less likely to get into trouble with their neighbors.

Read more . . .