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Why arched backs are attractive

Researchers use eye-tracking technology and 3-D models to investigate how some postures are perceived to be more attractive than others

Springer

Researchers have provided scientific evidence for what lap dancers and those who twerk probably have known all along - men are captivated by the arched back of a woman. A team led by Farid Pazhoohi of the University of Minho in Portugal used 3D models and eye-tracking technology to show how the subsequent slight thrusting out of a woman's hips can hold a man's gaze. The findings are published in Springer's journal Evolutionary Psychological Science. Studies of animals such as rats, guinea pigs, sheep, cats, ferrets and primates have shown that this so-called lordotic posture, in which the lower spine is curved towards the belly, can signal the readiness of females to mate. According to Pazhoohi, this posture may have also evolved as part of the courting behaviour of humans, and as a signal of a woman willing to be courted by a man.

The researchers set out to study the role that body posture plays in the development of human mate attraction and selection. To do so, six computer-generated 3D models of a woman's upper body was generated. The models' backs were manipulated at slightly different yet normal body angles. This resulted in variations in how their backs arched and their buttocks extended outwards. Three different views (from the front, side and the back) of each of the models were then presented to 82 undergraduate men and women, who had to rate how attractive they found each posture. Eye-tracking technology was used to monitor the participants' gaze while they were looking at the images.

The results show that small changes in the angle of a woman's back influence how attractive others perceive her to be. The more arched the back of the 3D model, the more appealing the men and women participating in the study rated it to be.

"Increased curvature increases the perception of attractiveness," explains Pazhoohi.

Results of the eyetracking part of the study further showed that participants, irrespective of their gender, looked at the rear view of the models much longer than the side or front angles. The female participants looked longer at the waist area, while the men focused their attention on the models' hips. Interestingly, both the results of attractiveness ratings and eyetracking indicate the effect is more robust from side and back-side views compared to the front where the hip is most visible.

"The latter highlights the unique influence of an arched back on the perception of attractiveness," explains Pazhoohi. "The perception of attractiveness and visual attention to the hip region suggests that lordosis or the arching of the back might signal human females' proceptivity or willingness to be courted. This also might explain why women wear high heel shows and why wearing high heel shoes increases womens' attractiveness."

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Reference: Pazhoohi, F. et al (2017). Arching the back (lumbar curvature) as a female sexual proceptivity signal: An eyetracking study, Evolutionary Psychological Science DOI 10.1007/s40806-017-0123-7

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