Social

Psychologist Matthew D. Lieberman draws on social neuroscience to argue that the need to connect with other people runs deeper than the need for food or shelter. The brain, he says, spends its idle time learning about other people and our relation to them, so that by age ten each person has logged some 10,000 hours making sense of people and groups. Brain-imaging studies, many from his own UCLA lab, show social pain and pleasure registering much like physical pain and pleasure; a breakup can hurt like a broken limb. He also examines how we read others' minds and how closely our sense of self is tied to the groups in our lives, with lessons for schools and workplaces.

In an interview, Stephen Lew, director of The School of Positive Psychology, included it among the books he would recommend to young people who want to follow his professional path.