Researchers turn to 3D technology to gauge attractiveness of human body

Sample clips from 360-degree video evaluated for attractiveness. Image: Brunel University, London, UK

Good body symmetry is an unspoken cue of a person's health and potential reproductive status, according to researchers.

3D images of 77 male and female volunteers  were rated for attractiveness by other study volunteers. From their responses, researchers at Brunel University in London conclude that broad shoulders, curvy waists and smooth movement are conspicuous signals that a potential mate is healthy and that makes them attractive to the opposite sex. Less conspicuous cues are symmetrical bodies which also are a sign of health and reproductive quality. 

New research from a London research institution suggests that your body proportions, shape and symmetry are sending unsubtle cues about your health and desireability as a reproductive partner. 

“It seems that because bodily asymmetries are too subtle to be seen with the naked eye, evolution has instead engineered more conspicuous signals and displays, such as broad shoulders, curvy waist lines or smooth dance moves to indicate mate quality,” according to study lead Dr. William Brown of Brunel University’s School of Social Sciences and School of Engineering and Design.

According to the researchers, the study offers an explanation for the correlation between attractiveness and bodily characteristics like height, breast size, long legs, broad shoulders or a curvy figure. The study also explored the degree of asymmetries between the left and right sides of the body because degree of symmetry or "fluctuating asymmetry" is a widely used marker of a species' -- including humans -- developmental stability, according to the researchers.  

A 3D optical body scanner was used to measure body proportions of 77 volunteers (40 males and 37 females) and 87 other volunteers then assessed how attractive the bodies of the opposite sex were (minus the heads), in 360-degree computer-rendered images.

The body scanner uses seven cameras to scan the entire human body in less than six seconds and produces a true-to-scale 3-D body model within minutes, according to study co-author, Dr. Jinsheng Kang from Brunel’s School of Engineering and Design. 

“The 3D body scanner accurately extracts hundreds of measurements of the human body, including volume, in six seconds and removes a potential source of measurement error, the human experimenter,” said Kang.

Among the key findings:  

When men and women were asked to rate the attractiveness of the 3D images, men rated the female forms with less masculinity most attractive, and women found the male forms with more muscular attributes most attractive.

Typically masculine features correlated with fewer departures from perfect bodily symmetry in males but with more asymmetry in females, suggesting that those with good development and health may have bodies that exaggerate sex-typical bodily features.

“It is widely believed that human beings are attracted to one another as a result of genotypic and phenotypic quality – in other words, their prospect as a mate who will yield higher quality offspring for the chooser,” according to Brown.

“My previous research suggested that bodily symmetry is not necessarily what people attend to when they find someone attractive but nonetheless the physical cues that they do prefer may reveal an individual’s underlying developmental quality (i.e. degree of symmetry). This new research identifies an explanation for the correlation between bodily shape and attractiveness: your body proportions, shape and stature are signals that conspicuously advertise your good development or health and therefore the degree to which you are a desirable reproductive partner. In many species fewer departures from perfect symmetry are associated with good development, health and reproductive success.” 

The study, "Fluctuating asymmetry and preferences for sex-typical bodily characteristics," by William M. Brown, Michael E. Price, Jinsheng Kang, Nicholas Pound, Yue Zhao, and Hui Yu was published August 18 in the Proceedings of the National Academy of Sciences (PNAS).