Esther Perel: The secret to desire in a long-term relationship

In long-term relationships, we often expect our beloved to be both best friend and erotic partner. But as Esther Perel argues, good and committed sex draws on two conflicting needs: our need for security and our need for surprise. So how do you sustain desire? With wit and eloquence, Perel lets us in on the mystery of erotic intelligence.

Best of Ted - Matt Ridley: When ideas have sex

British author Matt Ridley argues that, through history, the engine of human progress and prosperity has been, and is, "ideas having sex with each other."