People perceive facial features to be an indicator of personality, especially when looking for a partner, according to research.
Psychologists and biologists at Durham, St Andrews and Liverpool universities have found that most people are attracted not only to partners who look like themselves but to those who look as if their personalities are similar.
Two studies in which men and women were asked to rate photographs of people of the opposite sex by attractiveness and personality traits found that they were most likely to prefer those who matched themselves physically and in their perceived persona. Even when researchers took age and attractiveness into account, people were influenced by characteristics in faces they perceived as showing openness, neuroticism, extroversion or conscientiousness.
People attribute personality types to features: smiling is seen as sociable; large open eyes denote alertness; small hooded eyes are seen as betraying a lack of imagination; high foreheads are perceived as a sign of intelligence, while youthful looks can convey naivety and innocence.
An analysis of the personality traits that appeared to be shown in the faces of married couples found that the longer people had been together, the more they looked like each other. This may reflect couples growing more similar in apparent personality over time, or that those appearing alike in personality stay together longer.
Researcher Tony Little, a biology lecturer at Liverpool, said: "It could be something to do with shared experiences and personality traits and the way these are reflected in our faces, such as laughter lines in the faces of couples who laugh a lot together."