Violence and brutality are grim realities of life. Are some of us born that way, or can anyone be pushed into committing acts of cruelty? In this hour, TED speakers explore the sinister side of human nature, and whether we're all capable of violence. Featuring Four TED Talks Philip Zimbardo: Why Do Good People Do Bad Things?; Jim Fallon: What Does The Mind Of A Killer Look Like?; Leslie Morgan Steiner: Why Don't Domestic Violence Victims Leave?; Steven Pinker: Is The World A Less Violent Place?