Why religion? "If you look at three- to five-year-olds, when they do something naughty, they have an intuition that everyone knows they've been naughty, regardless of whether they have seen or heard what they've done. It's a false belief, but it's good preparation for belief in an entity that is moral and knows everything," he says. "The idea of invisible agents with a moral dimension who are watching you is highly attention-grabbing to us."