I've never been much for hugging people I'm not related to. But maybe I should reconsider after hearing the testimony of Paul Zak, author of the new book The Moral Molecule . Zak is a pioneer in the study of oxytocin, the neurotransmitter associated with feelings of empathy and affection and trust. He was, for example, the first to demonstrate that artificially raising oxytocin levels (via nasal spray) makes people more trusting of potential collaborators. Having increased oxytocin levels in a laboratory setting, he decided to try doing it in the real world. One result, as he explains here, is that he became known as "Dr. Love."