Blame biology for men's love of booties, UT study says

20 women beloved for their booties The booty-approving sir Mix-A-Lot would definitely give the thumbs up to these celebs who are beloved (in part) for their backsides.

Nicki Minaj 20 women beloved for their booties The booty-approving sir Mix-A-Lot would definitely give the thumbs up to these celebs who are beloved (in part) for their backsides.

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Here's some research out of the University of Texas at Austin that seems certain to get somebody riled up: A new study published online in Evolution and Human Behavior attributes men's preference for women with a nice lumbar curve to prehistoric influences.

Or as Sir Mix-A-Lot might've put it, for men who like big butts, it's evolution that they can't deny.

The back story here is that when it comes to finding a mate, men show a preference for women with a 45.5-degree curve from back to butt, say the study authors, who include David Buss, a UT Austin psychology professor.

"What's fascinating about this research is that it is yet another scientific illustration of a close fit between a sex-differentiated feature of human morphology — in this case lumbar curvature — and an evolved standard of attractiveness," Buss said in a statement. "This adds to a growing body of evidence that beauty is not entirely arbitrary, or 'in the eyes of the beholder' as many in mainstream social science believed, but rather has a coherent adaptive logic."

That adaptive logic relates to the fact that, as any woman who has ever been pregnant will attest, carrying babies to full term is a challenge for a species that walks upright on two feet.

Over time, ancestral women evolved "wedging" in the third-to-last lumbar vertebra to help shift their center of mass over their hips, the researchers said.

And men who preferred and selected these women as mates would have reaped several important benefits, "including having a mate who was less vulnerable to spinal injuries, better at foraging during pregnancy and better able to sustain multiple pregnancies without debilitating injury," the researchers said.

This conclusion led to their research hypothesis that men evolved sensitivity to cues to lumbar wedging as part of regulating mating attraction.

Early men could not have directly observed potential mates' vertebrae, so they had to go with visible cues, such as the curvature of the lower back, the authors said. The optimal angle, according to orthopedic studies, is 45.5 degrees, the authors state.

The new research was led by UT Austin alumnus David Lewis, a psychologist at Bilkent University in Ankara, Turkey, and consisted of two studies, both involving men recruited at UT Austin.

In each study, participants were shown profile images of women with varying angles of lumbar curvature and were asked to rate the attractiveness of each image. The second study added a variable related to buttock mass to gauge that factor's influence.