The Better Angels of Our Nature by Steven Pinker

And certainly the police and government have had a huge role in reducing violence. And if we both are constantly trying to kill each other, we're both worse off. I might get an advantage if I harm someone else for my benefit, but on the other hand, he feels the same way.

If there's a common denominator - in the long run, violence really is irrational. PINKER: There are a lot of individual whys because the decline of war, decline of homicide, decline of capital punishment, and so on take place over different time scales. MARTIN: Why is the rate of violence going down around the world? But both of those figures are at a fraction of what they were in the '60s, '70S and '80s. There has been a small increase in homicide in the United States in the last three years. Because of the Syrian civil war, the rate of death in warfare has drifted upward a little bit in the last five years. The impression that some kinds of violence have gone up over the last five years has some truth to it. But if you count the number of parts of the world that are violent versus those that aren't, then you see that the world is becoming more peaceful.

If you certainly choose the most violent parts of the world at any given time, they're going to be pretty violent. MARTIN: And you say this is a worldwide phenomenon. The rate of death in war fell by a factor of 100 over a span of 25 years. The rate of violent crime in United States has fallen by more than half in just a decade. And in all cases, the long-term historical trend, though there are ups and downs and wiggles and spikes, is absolutely downward.

I looked at homicide, looked at war, looked at genocide, looked at terrorism. STEVEN PINKER: The only way you can really answer the question - has violence gone up or down? - is to count how many violent incidents have there been as a proportion of the number of opportunities, and has that gone up or down over the course of history? And that's what I tried to do in the book. He says the answer is no, a thesis he put forth in his book 'The Better Angels Of Our Nature: Why Violence Has Declined.' We reached him in Cape Cod, Mass., via Skype, and I asked him to explain his argument. So we posed that question to Harvard University psychology professor Steven Pinker. You can see why reasonable people might wonder if the world is falling apart or at least becoming more violent. There was also the assault on a park in Bangladesh and on the airport in Brussels, the suicide bombings in Baghdad, not to mention the spate of mass shootings here in the U.S. But those are just two of recent violent episodes that shocked the world. As you know, we've been following the attack on the boardwalk in Nice and the attempted coup in Turkey, both of which claimed dozens of lives.

The Better Angels of Our Nature by Steven Pinker