Which Emotion Is The Hardest To Fake?

We've all done our fair share of faking it. Whether it's a canned excited response when that one particularly eccentric aunt gives you a Christmas sweater for the fifth year in a row, or a friendly smile when greeting someone you don't particularly like - putting on a good face often seems like the socially appropriate thing to do. Unfortunately not all expressions are so easy to fake.

Unlike the commonly deployed social smile, distressed expressions - anger, fear, sadness, and occasionally surprise - prove much more difficult to display on command. These expressions cause tension throughout the face as one part of the brain tries to control an expression caused by another part of the brain.