By Karin Zeitvogel (AFP)

WASHINGTON — Beauty is not so much in the eye of the beholder as in the measurements between the eyes, mouth and ears of the woman being observed, US and Canadian researchers have found.

Shania Twain was part of a study to determine what defines beauty - Photo: AFP

In four experiments aimed at finding "an ideal facial feature arrangement," US and Canadian researchers asked students to compare color photographs of the same woman's face, in which the vertical distance between the eyes and mouth, and horizontal distance between the eyes, had been doctored using Photoshop.

The features -- eyes, mouth, nose, contour and hair -- remained the same and a woman's face was only compared to her own, never to another's.

Students looked at different pictures of the same woman's face laid out side by side and selected the face they found more attractive.

In all four experiments, they chose the faces with specific proportions that the researchers have dubbed the "new golden ratio."

Two of the experiments tested for the ideal distance between the eyes and mouth as compared to total face length, measured from the hairline to the chin. Both came up with 36 percent as the golden ratio for "the maximally attractive face."

The other two experiments measured both the ideal length and width ratios.

They both confirmed 36 percent as the golden ratio for the length of the maximally attractive face, and 46 percent as the ideal width ratio -- where the distance between the eyes is 46 percent of total face width, measured between the inner edges of the ears.

Happily, the 36/46 percent ratios "correspond with those of an average face," the study said, meaning there's no pressing need to get out the measuring tape and calculator or to rush to the plastic surgeon.

In fact, there are easy, non-invasive ways to trick beholders into thinking a woman's face is "maximally attractive," says the study, published in Vision Research.

Changing the hairstyle, is one example.

"Our study... explains why sometimes an attractive person looks unattractive or vice versa after a haircut, because hairdos change the ratios," said Kang Lee, a professor at the University of Toronto and one of the lead authors of the study.

Lee also told AFP that the researchers studied the faces of a few celebrities.

"Angelina Jolie does not have golden length and width ratios," he said.

"Elizabeth Hurley gets the golden ratio for length but is different from the width golden ratio by one percent."

But Canadian country pop musician Shania Twain has "both the length and width ratios."

The study looked only at white women. More research is needed to determine if the golden ratios for men's faces, the faces of people of other races, and children's faces, are the same as for the women's faces in the study.