Once upon a time, our earliest human ancestors all had a permanent case of 'angry face' due to the big bony ridges on their foreheads. Over time we've evolved flexible brows that can communicate our complex emotions. Evolutionary anthropologists are trying to figure out why. Join Mindy and Guy Raz for an ancient family reunion, and discover the who, what, when, where, why, how and WOW in the world of eyebrows! Originally Aired August 13th 2018.