Defining charisma is easy: compelling attractiveness or charm. Describing charisma is a little like defining pornography; you know it when you see it. President Bill Clinton has it. So did President Ronald Reagan. Actor Larry Hagman had it. Billionaire Oprah Winfrey’s got it. Princess Diana was charismatic, too.

We all know lawyers and judges who have it. One lawyer could be tall, beautiful and smooth as velvet. Another could be a frumpy elderly guy who resembles a troll. Yet both are extremely charismatic. How can that be? Is charisma something you’re born with — a genetic tendency that’s innate to your personality? Or can it be learned from reading self-help books and signing up for charisma-building workshops?