Ron Gutman reviews a raft of studies about smiling, and reveals some surprising results. Did you know your smile can be a predictor of how long you’ll live — and that a simple smile has a measurable effect on your overall well-being? Prepare to flex a few facial muscles as you learn more about this evolutionarily contagious behavior.

Equally interesting is the user conversation that is taking place alongside this video “Do you have a story where yours or someone’s smile totally changed the outcome of an unpleasant situation?” Read the comments here.