Researchers from UCSD and the University of Toronto have found the exact formula for facial beauty — down to the millimeter.

UCSD psychology professors Pamela Pallett and Stephen Link, along with University of Toronto professor Kang Lee, surveyed hundreds of students to discover a ratio of the most attractive female face. They recently published their findings in Vision Research magazine.

Previous research found that the most appealing face could be determined by digitally and mathematically averaging the facial features of any given group of people. To test this hypothesis, Link, Pallett and Lee gathered groups of roughly 20 to 40 UCSD students to conduct a new experiment.

The subjects were shown pictures of the same white female, with altered facial ratios — different proportions between features — and asked to choose the most appealing face.

“In Experiment One, for example, there were 10 alterations to an original face, resulting in 11 faces,” Link said. “These were each paired against each other, and subjects were asked to judge which face appeared more attractive.”

The researchers established that the most attractive face was formed when the vertical distance between the eyes and the mouth is approximately 36 percent of its length, and the horizontal distance between the eyes is approximately 46 percent of the face’s width. About 63,000 images were used to determine the two measurements — one for eye width and one for the distance between eye and mouth — with extreme accuracy.

Link said the findings showed that most people have an intuitive idea of facial beauty.

“People have an ideal for beauty in their own mind,” Link said. “You can ask them about it, and even if they think they don’t know what their ideal is, from comparative judgments, we can discover what their ideal is.”

According to Link, the purpose of the project was not simply to find an equation for beauty, but to gain an understanding of how people decide what is attractive and what is not.

While Pallett and Link only analyzed the facial features of white females, they said they plan to diversify their studies.

“We have done a lot of research with Chinese subjects,” Link said. “I absolutely expect the results to be different. Beauty is a cultural and genetic sort of thing.”

Readers can contact Xue Mao at [email protected].