Beautiful people are seen as good looking even if they distort their faces into grimaces of disgust, surprise, fear or anger, according to new research.
Unattractive people are seen as unappealing even if they smile broadly because others recognise the underlying structure of the face, not the expression, although expressions can make a small difference as a signal of whether someone is worth pursuing as a mate, the researchers found.
Dr Ed Morrison, of the Department of Psychology at the University of Portsmouth, wanted to study whether attractiveness was more to do with how you look or how you present yourself, and found facial attractiveness remained steadfast in other people's minds no matter what expression a person displays.
Dr Morrison said: "The hard tissues of the face are unchangeable and it seems people, both men and women, can tell if the underlying structure of the face is attractive or not no matter what expression a person has on their face."
The study found small differences in how others rated attractiveness based on facial expression, but the variations were limited and only about half as important as variations between the people themselves, with happy expressions being no more attractive than neutral expressions.
Dr Morrison said: "People do make decisions about the attractiveness of others based on their facial expression, but this has less to do with deciding if they are attractive and much more to do with deciding if someone is worth pursuing as a mate.
"For example, disgust or contempt are a clear signal to not pursue, while smiling or neutral expressions are likely to mean mating effort will be rewarded."
The study, published in the Journal of Nonverbal Behavior, was conducted by asking 128 men and women to rate the attractiveness of 30 men and women, each of whom was photographed expressing happiness, neutral, sadness, surprise, fear, anger and disgust.
Both men and women rated attractiveness of each face relatively equally, indicating the sex of the model and the sex of the person rating them played no part in their decision.
Dr Morrison said: "Our findings are consistent with the idea men and women see attractiveness in the same way."