Predictive Smiles
Matthew Hertenstein asked alumni of his university to answer questions about their current sexual relationships and whether they had ever been divorced (”Smile intensity in photographs predicts divorce later in life”; .pdf file here).
His team then looked up pictures of their volunteers in the university’s yearbooks and graded the degree of their smiles. The less a person smiled the more likely he or she was to have been divorced over the course of a lifetime.
The study looked at over 600 alumni & a group of 55 non-alumni (the latter were asked to send in photos of themselves, but were not told that the study was about smiling). The researchers rated the photos of the subjects on a scale of 2 to 10.
The relationship between smiling and divorce even held up among the non-alumni who sent in photographs of themselves as children.
The never-divorced had their smiles rated on average at 5.9 for alumni and 5.2 for non-alumni, while the divorced scored about 5.1 and 4.4, respectively. The lowest-scoring people were 3 times more likely than the biggest smilers to divorce.