Why do human beings engage in courageous acts of compassion but also perpetrate violence?

Could the apparent flip-flopping morality of our species have a hidden explanation?

The Moral Molecule is a first-hand account of the discovery of a molecule that makes us moral. It reveals that compassion is part of our human nature, why loneliness can kill you, and why your neighbor may be a psychopath.    From the laboratory to the jungles of Papua New Guinea, Paul Zak takes you on an amazing journey that reveals what it means to be human.