If you've ever had a compulsive liar in your life, one who lied to you so convincingly that when the truth finally came out you were left not trusting or believing anyone, skeptical of all the subtle expressions flashing on friend's faces, this story is for you. It's a Radiolab podcast by Robert Krulwich, Jad Abumrad and Ellen Horne. The story is told in three parts, the final part going deep into the psychology and unique physiology, yes, the physical differences in the brains of liars.
Listen on a long drive, or somewhere quiet. And listen to the show in it's entirety. Let Radiolab explain everything, it just might set your world back on it's axis.