Is human civilization growing less violent? Cognitive scientist Steven Pinker argued the point in his 2011 book 'The Better Angels of Our Nature,' in which he also defined the 'five inner demons' that push us to wrath. Know them -- speak their true names -- and you have the power to undermine their influence. In this episode of Stuff to Blow Your Mind, Robert and Christian explore Pinker's thesis and draw in supporting research and dissenting opinions.