If you ever needed someone to make the case for why it’s important to smile, think of today’s talk by Ron Gutman at TED University . (That’s a short series of presentations by TED conference participants.) Gutman, a member of the TED conference team and CEO of health-information company HealthTap , pointed out a study from the University of California, Berkeley that measured smiles in high school yearbook photos and looked at what the students were up to decades later. The bigger smilers were more likely to be in a long-lasting marriage and to have a better sense of personal well-being. Another study found that the size of

major league baseball players’ smiles in their trading-card photos predicted longevity. Players who didn’t smile at all lived an average of 72.9 years, those with some semblance of a smile lived  75 years and those with a “beaming smile” lived to be nearly 80. Some other fun factoids: smiling is contagious, and children do it as often as 400 times a day, says Gutman. In brain studies, a smile stimulates the brain as much as 2,000 bars of chocolate and lowers stress hormones like cortisol and adrenaline and while boosting positive ones, he says. Photo: Getty Images

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TED2011: Smiling Makes the World Go Round