Why Men Love Curves

By Jane Farrell

Men’s preference for women with curvy backsides seems traceable to prehistoric influences, according to researchers from The University of Texas at Austin. 

The investigators’ study was published in the journal Evolution and Human Behavior. According to a release from the university, the research looked at men’s preference for women with a “theoretically optimal angle of lumbar curvature,” a 45.5 degree curve from back to buttocks. That curve, the news release said, allowed ancestral women to better support, provide for, and carry out multiple pregnancies.

“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,” said the study’s co-author David Buss, a UT Austin psychology professor.

“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.”

The research, led by UT Austin alumnus and Bilkent University psychologist David Lewis, consisted of two studies. The first looked at vertebral wedging, an underlying spinal feature that can influence the actual curve in women’s lower backs.

The news release said that about 100 men rated the attractiveness of several manipulated images displaying spinal curves ranging across the natural spectrum. Men were most attracted to images of women exhibiting the hypothesized optimum of 45 degrees of lumbar curvature.

The second study addressed the question of whether men prefer this angle because it reflects larger buttocks, or whether it really can be attributed to the angle in the spine itself. About 200 men looked at groups of images of women with differing buttock size but with a 45.5-degree curve. Men consistently preferred women whose spinal curvature was closer to optimum regardless of buttock size.

“This enabled us to conclusively show that men prefer women who exhibit specific angles of spinal curvature over buttock mass,” said the study’s co-author Eric Russell, a visiting researcher from UT Arlington.

This morphology and men’s psychological preference toward it have evolved over thousands of years, and they won’t disappear overnight, according to the university’s news release.

“This tight fit between evolutionary pressures and modern humans’ psychology, including our standards of attractiveness, highlights the usefulness that an evolutionary approach can have for expanding our knowledge not just of the natural sciences, but also the social sciences,” Lewis said.