People might be incredulous about the popularity of Kim Kardashian’s backside but a recent scientific study might help to shed some light as to how some men, ‘in spite of themselves’, find it appealing, or, more appealing than others. The paper authored by researchers from the University of Texas and published online in Evolution and Human Behaviour focuses on the prehistoric influence on the modern man’s inclination to women with curvy backsides.
Beauty Standards: Product of the Beholder’s Eye or Evolution?
The scientists attempted to analyse men’s mate preference for females with a “theoretically optimal angle of lumbar curvature”, estimated to be a 45.5 degree curve starting from the back to the butt. It is believed that this angle allowed women of the past to cater for several pregnancies, as it is said to provide better support to carry children in the womb.
“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.”
Different spine angles. Picture credits: The University of Texas at Austin.
1st part: which spinal curve do men find most appealing?
The first part of the research entailed the vertebral wedging which is an underlying spinal feature. The latter is said to affect the curve in the lower backs of women.
To determine what is found to be more appealing to males, 100 men were asked to rate the attractiveness of different spinal curves.
The findings showed that the men were most attracted to the images depicting women with the hypothesised optimum angle of 45 degrees.
What’s with the 45 degrees curvature?!
“This spinal structure would have enabled pregnant women to balance their weight over the hips,” Lewis said. “These women would have been more effective at foraging during pregnancy and less likely to suffer spinal injuries. 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.”
2nd part: spine angle or big butts?
The second part of the study was to determine whether men’s preference for this angle was because of the resulting larger butts, or because of the angle of the spine itself.
200 men were asked to rate images of women with different butt sizes but with all having the 45.5 degree curve.
It was found out that men 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.
Evolution & the psychology behind the spine curve
The researchers believe that the preference of the men has evolved over hundreds and hundreds of years, and that this psychological trait will persist.
“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.