Cognitive scientist Steven Pinker was the guest at the Kentucky Author Forum on Oct. 2, 2012, interviewed by NPR's Neal Conan. Pinker is a Harvard College Professor and Johnstone Family Professor in the Department of Psychology at Harvard University. He conducts research on language and cognition and is the author of numerous books, including The Stuff of Thought: Language as a Window Into Human Nature, and most recently, The Better Angels of Our Nature. In The Better Angels of Our Nature, Pinker examines human violence through the centuries. We’ve all had the experience of reading about a bloody war or shocking crime and asking, “What is the world coming to?” But we seldom ask, “How bad was the world in the past?” In the book, Pinker argues that violence in the past was actually much worse than now. Tribal warfare was nine times as deadly as war and genocide in the 20th century. The murder rate of Medieval Europe was more than thirty times what it is today. Slavery, sadistic punishments, and frivolous executions were unexceptionable features of life for millennia, then suddenly were targeted for abolition. Wars between developed countries have vanished, and even in the developing world, wars kill a fraction of the people they did a few decades ago. Rape, battering, hate crimes, deadly riots, child abuse, cruelty to animals—all substantially down. How could this have happened, if human nature has not changed? What led people to stop sacrificing children, stabbing each other at the dinner table, or burning cats and disemboweling criminals as forms of popular entertainment? The key to explaining the decline of violence, Pinker argues, is to understand the inner demons that incline us toward violence (such as revenge, sadism, and tribalism) and the better angels that steer us away. Thanks to the spread of government, literacy, trade, and cosmopolitanism, we increasingly control our impulses, empathize with others, bargain rather than plunder, debunk toxic ideologies, and deploy our powers of reason to reduce the temptations of violence.