You Are Not So Smart: Why You Have Too Many Friends on Facebook, Why Your Memory Is Mostly Fiction, and 46 Other Ways You're Deluding Yourself

by David McRaney

Psychologist David Buss has spent his career studying the preferences of men and women when it comes to selecting a mate both for short-term flings and long-term relationships. In his book The Evolution of Desire, he points to one crucial aspect which seems to be held above all others when men are making a snap judgment about physical attraction—the hip-to-waist ratio. In many studies around the world, no matter what cultural significance is placed on body type, a ratio in which the waist is about 70 percent the width of the hips is always preferred. According to Buss, a hip-to-waist ratio of .67 to .80 correlates to health, reproductive and otherwise. Women with this ratio truly are healthier, and this is something men know unconsciously. Psychologist Devendra Singh’s 1993 study of Playboy centerfolds showed although the women in the magazine had become thinner over the years, their average hip-to-waist ratio remained a constant .70.