Zajonc to experiment, to test the phenomenon of life that the longer couples face more and more similar to each other. He analyzes the photographs when the newly married couple and the pictures 25 years later. Zajonc estimate, an elderly couple seemed more like because people will imitate the expression on his friend's face.
"In other words, if your spouse has a good sense of humor and lots of laughs, then he will develop laugh lines around their mouths. So did his partner," says Zajonc. "Other evidence also showed that men and women the possibility of initially attracted to someone who has the same personality."
In 2006, in one study, scientists at the University of Liverpool asked for volunteers to look at portraits of men and women and assess the personalities of people in the photo. The participants did not know where the couple live figure in the photographs, but most couples who live together long considered to have the most similar personalities.
The researchers concluded, has the personality traits of interest may exist correlation to make the face look attractive. In a study of twins, scientists from the University of Western Ontario found that study participants tended to choose partners with similar genes; partner of each of identical twins have a higher similarity than pairs of non-identical twins.