Scientific Reasoning for Men’s Sexual Preference

There may be evolutionary roots for what body types a man finds attractive.




Guys’ fascination with us ladies’ rears probably goes back farther than our species.  Recently, a psychological study at the Austin campus of University of Texas has shed new light on the modern standard of beauty.  They attribute men’s preferences for a curvy rear end to be from prehistoric influences.

Published online in Evolution and Human Behavior, the study investigated the mate preferences of heterosexual men.  There was a preference for women with a theoretical ‘optimal angle of lumbar curvature’ — 45.5 degree curve from the back to the buttocks.  The closer to perfection, the better an ancestral woman could support, provide for and survive multiple pregnancies.


Woman (a) has less vertebral wedging, and woman (b) has greater wedging, who is more likely to be on the ‘twerk team?’ Credit: The University of Texas at Austin



The lumbar curvature would seem to be the feature of an evolved standard of sexual attractiveness.  Co-author of the study, David Buss, a psychology professor at UT Austin stated, “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.”

Led by UT Austin alumnus and Bilkent University psychologist David Lewis, the research consisted of two studies.  The first was about vertebral wedging, a feature of the spinal cord which cn influence the actual curve in a woman’s backside.


The protrusion of the buttock associated with gluteal development (a) indicates physical fitness, adipose tissue deposition (b), and vertebral wedging (c). Notes: all three factors, muscle, fat and spinal curve go into making the bum; this isn’t a comparative diagram.


Nearly a hundred men rated the attractiveness of several images displaying curves in the spine across the natural spectrum.  It found that men were mostly attracted to images of women displaying the hypothesis of a 45 degree optimum angle in lumbar curvature.

“This spinal structure would have enabled pregnant women to balance their weight over the hips,” making them, “more effective at foraging during pregnancy and less likely to suffer spinal injuries,” Lewis said.  “In turn, men who preferred these women would have had mates who were better able to provide for fetus and offspring, and who would have been able to carry out multiple pregnancies without injury.”

The second study sought to determine if men prefer this angle because of the illusion of a larger buttocks or if their fascination can be attributed to the angle itself.  About 200 men were given images of women with different sized bums and vertebral wedging, but maintaining a 45.5 degree curve.  Consistently, men were recorded as preferring the women with spinal curvatures close to optimum, no matter how big the backside was.


I must be somewhere between a 34 and a 43… omg

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

Men’s psychological sexual preference evolved over thousands of years and won’t be disappearing over night.  “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,” said Lewis.



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