TEDTalks : Ron Gutman: The hidden power of smiling - Ron Gutman (2011)

TEDTalks : Ron Gutman: The hidden power of smiling - Ron Gutman (2011): "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."