SUNDAY, April 24 (HealthDay News) -- While it may be true that beauty is in the eye of the beholder, a new computer model helps reveal what's behind peoples' ideas of facial attractiveness.

Many studies have concluded that people are drawn to "average" faces and those who fit the conventional notion of attractiveness for a person's gender -- "masculinity" in men and "femininity" in women. But psychologists Christopher P. Said of New York University and Alexander Todorov of Princeton University believe attractiveness is more complex than that, so they created a computer model to identify and measure those complexities.

The psychologists used thousands of faces and their ratings, from 20 male and 20 female students rating opposite-gender faces, to build the computer program.

The computer model tested 50 "dimensions" of facial features, which were divided into two categories -- shape and reflectance. Shape includes things such as nose size or plumpness of lips, while reflectance includes things such as facial lightness, darkness and color, such as red lips or shadowed eyes.

The investigators found that men typically want women's faces to have feminine shape and feminine reflectance (such as plump lips and wide eyes), while women typically want men's faces to have masculine reflectance (such as swarthier skin) but a feminine shape.

The results show that masculine and feminine attractiveness are not equal and opposite, according to the researchers.

The study authors also found that the appeal of average faces is less straightforward than previously believed. While both men and women find average faces attractive, the most average faces are not considered the most attractive.

The study is slated for publication in an upcoming issue of the journal Psychological Science.

In a news release from the Association for Psychological Science, the authors point out that their study has limitations, including the fact that only a few dozen college students participated in the research.

And while theoretically a computer program might be able to determine the attractiveness of an artificial face, people have unique ways of rating beauty and may come to different conclusions when faced with a real person.

More information

The Perception Lab investigates the facets of face perception.