Invisibilia: The Personality Myth

Airs Sunday, July 31, at 6 p.m. We like to think of our own personalities - and those of our spouses, children and friends - as predictable and constant over time. But what if they aren't? In this episode, Alix 
Spiegel visits a prison to explore whether there is such a thing as a stable personality. And Lulu Miller asks whether scientists can point to a single thing about a person that doesn't change over time. The answer might surprise you.