Want to know if your marriage will last? Take a look at their college yearbook photo.
Researchers rated the smiles from those pictures on a 1-to-10 scale of intensity.
None of the people with the most intense smiles in their yearbooks had divorced. But, among those with the weakest smiles, one in four marriages ended broken.
"Maybe smiling represents a positive disposition towards life," said study leader Matthew Hertenstein, a psychologist at DePauw University in Indiana. "Or maybe smiling people attract other happier people, and the combination may lead to a greater likelihood of a long-lasting marriage. We don't really know for sure what's causing it."