How do you define beauty? What are the factors that govern whether or not you find someone physically attractive? This question has plagued philosophers and artists for millennia. And now, modern scientists think they're close to finding that magical formula for physical beauty. Aside from the obvious cues,--youthfulness, smooth skin, bright eyes--it pretty much all comes down to math.
When it comes to sexual attraction, we've known for some time that men prefer a waist-to-hip ratio of around 70%. And although opinions about a woman's ideal weight have shifted throughout history, that 70% ratio has been a consistent measure of her beauty.
Another thing we've noticed is that across cultures (and even across species), animals are most attracted to mates that have highly symmetrical faces. Some think that asymmetry may be indicative of underlying genetic problems, so we tend to seek out symmetry to improve our evolutionary chances of survival.
A southern California plastic surgeon named Dr. Stephen Marquardt continued in the tradition of famed mathematician Pythagoras when he claimed to find the golden ratio phi, popping up all over the ideal human face. He found that pretty people's mouths were 1.618 times wider than their noses, and that the widest point on their noses was 1.618 times wider than the narrow tip. He even claimed that the width of a supermodel's front two teeth is precisely 1.618 times the height of each tooth.
Since then, other researchers have found golden ratios of their own, but not of the Pythagorean variety. Studies at UCSD and the University of Toronto found that female faces were judged most attractive when the distance between the eyes and the mouth was roughly 36% of the overall length of the face, and when the distance between the two eyes was around 46% of the face's width. See, these researchers claim that we cognitively average all of the faces we encounter on a day-to-day basis. So those people that represent the most average face possible--the 36 and 46 percenters--are the ones we gravitate toward.
Now get this: repeated studies have found that people are most attracted to people who look like themselves. What's worse, they often choose mates based on how much they look like--you ready for it?--their parents! Let's hope that's an unconscious phenomenon.
And you won't believe what researchers at Albright College have been up to. They claim to have found the biological basis for gaydar. Yeah, you heard me: gaydar. In their study, straight men's faces were found to be more symmetrical than those of self-identified gay men. Ultimately, they claim that symmetry is a greater predictor of heterosexuality than masculinity.