Scientists have found that individuals in a crowd of strangers tend to join groups that contain people of similar levels of attractiveness. The new study, published in the journal PLOS ONE, also reveals that attractive women tend to be placed right at the center of these newly formed social groups.

Dunedin, a southern university town in New Zealand, happens to have a rather large stadium. A group of researchers from the University of Otago, also based there, decided to transform this contemporary colosseum into their own personal psychological laboratory. Within this 600 square meter (about 6,460 square feet) space, 172 people were asked to walk around and mingle.

The researchers mounted a high-definition sports video camera on the roof in order to track the subjects’ complex movements; its ability to keep an eye on so many “moving parts” made it perfect for tracking so many simultaneously moving people for this study.

The participants were also separately photographed before they were let loose in the stadium, and their attractiveness – a distinctly subjective trait – was rated by three members of the research team. This produced an averaged, single attractiveness score for each individual wanderer.

Apart from being asked to behave as they would under their own volition, they were requested to form groups of any number and composition on several occasions. When people felt like groups had formed, they were told to raise their hands.

^{Hello, social attractor! Attractive women tended to be at the nucleus of groups. lithian/Shutterstock}

On average, groups of six were the most common. They were all composed of people of roughly the same attractiveness score, and attractive women appeared to be at the center of many of them.

“Women and attractive individuals were also more likely than men and unattractive individuals to be in the center of their groups,” Jamin Halberstadt, a professor of psychology at the University of Otago and the study’s lead author, said in a statement.  “Our analysis could not confirm whether this was because they acted as 'social attractors,' although this is the likely explanation – as we didn't find evidence that they were jumping into the middle of the group as it formed.”

At several stages, the groups were asked to cooperate on a hunter-gatherer task, wherein they had to find 500 tiny metal washers, randomly scattered around the stadium. They found that those that were keen on integrating into groups early on in the study were less likely to put effort into this foraging task. The researchers say that this is confirmation of a concept known as “social loafing,” wherein those who feel part of a group hope that someone else they have briefly got to know will pick up their slack.

Attractiveness and laziness aside, the major achievement of this study was to find a way of staging a psychological experiment that involved combined cutting-edge observational technology without getting in the way of the subjects – something that’s actually quite difficult to accomplish.

“We've now found a happy medium by using a stadium-size laboratory and applying unobtrusive state-of-the-art tracking technology to participants' social behavior,” Halberstadt added.