Etcoff and her colleagues claim that men’s universal preference for a healthy hourglass figure is evidence that our ideas of attractiveness are adapted for survival.

The Bart Simpson picture worn by this Matsigenka woman shows that though they are one of the most isolated populations on earth, they aren't entirely immune from the western media

"There are no smoking guns, No fossils of minds," says Yu, of the absence of evidence for evolutionary psychologists. "There are no other species of humans. [Evolutionary psychologists are] stuck, they can’t see the past." That’s why it is necessary for evolutionary biologists to study other cultures, according to Yu.

But Etcoff, a psychologist at Harvard Medical School, argues that the beauty hierarchy is a natural and inescapable phenomenon. She cites examples like babies gazing longer at beautiful faces and good-looking adults being favored for jobs, as evidence that biology is destiny.

Yu and Shepherd’s research shows that ideas of beauty may be more variable than Etcoff assumes.

Men’s preference for an hourglass figure have driven reproduction of the species since human's animal origins, says Etcoff.