FRIDAY, March 26, 2010 (HealthDay News) -- If you're always the one in the photo flashing the biggest smile, a new study suggests you can count on living a long life.
Researchers from Wayne State University in Detroit evaluated the photographs of 230 Major League Baseball players who started playing before 1950, rating their smiles as nonexistent to full.
"People who had the most intense smiles lived the longest, compared to the other two," said Ernest L. Abel, a professor of obstetrics and gynecology and of psychology at Wayne State.
"The more intense smile, we infer, indicates an underlying happiness, if you will, a more positive attitude," he said. "It's hard to fake an intense smile."
The researchers gathered other information potentially linked with longevity from a longstanding data base on the players, such as college attendance, marital status, birth year and body-mass index.
They asked reviewers who didn't know the study's purpose to rate the player's smiles as a 1, 2, or 3, with 1 being no smile, 2 a partial, and 3, a broad full smile, the kind that makes your eyes crinkle.
As of June 1, 2009, all but 46 players had died, and they looked back to see if the smile intensity in photos was linked with longer life. It was.
On average, the longevity of the non-smilers was 72.9, 75 for the partial smilers and 79.9 for the big smilers.
The study was recently published in Psychological Science Online First.
The big smilers had what is known as a Duchenne smile, named after the French neurologist who discovered it. Cheeks and the corners of the mouth are raised, and crows-feet wrinkles appear around the eyes.
After Abel and his team controlled for variables such as marital status, birth year and body-mass index, they found the smile-longevity link still held. Those with the biggest smile were half as likely to die in a given year than the nonsmilers. But in this regard, broad smilers didn't differ significantly from partial smilers.
Ted Williams of the Boston Red Sox -- "a big smiler," Abel said -- died at 83.
But Bill Kennedy, who played for Cincinnati and other teams, died at 62, and Abel say he didn't have a big grin in the photos he looked at.
The new research builds on previous studies that linked smile intensity in childhood and college yearbook photos with marriage stability or life satisfaction later.
The study findings make sense to Sonja Lyubomirsky, a professor of psychology at the University of California, Riverside, and a happiness researcher who wrote The How of Happiness. "Most likely, the smiles are an indicator of the baseball players' dispositions," she said. The smiles could be reflecting happiness, optimism or resilience, she said.
Experts already have found those who are happier tend to live longer, she said. While it hasnt been proven to be cause-and-effect, she said, evidence is accumulating that happiness as a trait "does predispose people to live longer," she said.
What about those camera-shy types who don't like their picture taken and therefore don't smile? Lyubomirsky said that probably wouldn't affect the overall results, as there are bound to be camera-shy types among both happy and unhappy people.
So if you're a sourpuss who scowls at the camera, can grinning help you take a better picture and improve your life expectancy?
That's difficult to say, as it's way beyond the scope of the study. But it may not hurt. According to Lyubomirsky, "Darwin was the first to suggest that the outward manifestation of an emotion will intensify it."
To learn more about happiness, visit the American Psychological Association.