Forced smiles in photographs always look a little awkward, but real ones do more than help you look good. According to recent research, a genuine smile might actually help you live longer, too.
[A]30-year long study published in the Journal of Personality and Social Psychology found that women who displayed the Duchenne smile in their college yearbook photos had greater levels of well-being and marital satisfaction three decades later. Another study published this year in Psychological Science went further to make a connection between smiles and longevity. They found that professional baseball players who sported Duchenne smiles in their yearbook photo were only half as likely to die, in any given year, as those who had not.
While the study may be kind of specific, an honest smile never hurt anybody so it's always worth a shot.
What Makes an Honest Smile? [Scientific America]