Sometimes your joy is the source of your smile, but sometimes your smile can be the source of your joy.
― Thich Nhat Hanh

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.

This post originally appeared on