When men are under stress, they are more likely to find larger women’s bodies attractive.

So says a small study published Wednesday in the journal PLoS One. Researchers at London’s University of Westminster and Newcastle University, both in Britain, assembled 81 white male undergraduates to test a hunch (based on previous studies) that men under psychological stress might prefer bigger-bodied women than men who aren’t stressed might choose.

They divided the group in two, subjecting 41 men to a stressful experience that the study explains is commonly used in psychological research.

First, they were made to stand before a group of people who were seated in a conference room and pretend to be a job applicant. They had to deliver a five-minute, off-the-cuff speech explaining why they should be hired. They were made aware that they were being videotaped and evaluated for their body language and other components of their performance. But that wasn’t all: after they were done talking, they had to count backward from 1,022 – by 13s. Talk about stress!

Meanwhile, the other group of men simply sat quietly in a separate room.

After 20 minutes, all the men were presented with a standard set of images of women that’s often used in research regarding attitudes toward body size. The series consists of 10 black-and-white frontal-view photographs of leotard-clad women (whose faces have been blocked out) whose body sizes range from very thin (or “emaciated,” in the study’s parlance) to obese. They were asked to identify which body they found most attractive, or ideal. They also were asked to identify the smallest and the largest body they found appealing.

Why 20 minutes? That’s about how long it takes levels of the stress hormone cortisol to peak after exposure to a stressful situation, the study explains.

The study controlled for the men’s BMI, level of hunger and other factors that might have influenced their preference in female body type.

Sure enough, the men under stress identified larger bodies as their ideal choice and as the largest they found attractive; the stress-free men chose smaller bodies as ideal and as the largest they found attractive. Those differences disappeared at the lower end of the body-size scale, with both groups making similar choices when identifying the smallest body they found attractive.

The connection between experiencing stress and appreciating larger women’s bodies may seem random, but there’s some biological logic behind it. From the study [citations omitted]:

“It is now widely-acknowledged that body size ideals are, in part at least, shaped by an individual's resource security, such that heavier body sizes are preferred where or when resources are unpredictable or unavailable. This proposition highlights the fact that a primary function of adipose tissue is the storage of calories, which in turn suggests that body fat is a reliable predictor of food availability.  In situations marked by resource uncertainty, therefore, individuals should come to idealise heavier individuals, as fatness would be associated with access to resources. Conversely, thinness in such contexts may be associated with increased incidence of ill-health and, for women, ovulatory irregularities and lower capacity to support pregnancy.”

The study further notes that larger size may signal maturity, independence and other qualities tied to survival. It makes sense that a person under stress might seek out a companion with those traits.

The study has some limitations, its authors note. First, it’s possible that the control group got bored while quietly waiting and that that – or some other psychological factor, may have affected their choice. Also, the authors urge caution in extending their findings to apply beyond the realm of young white British males.

Still, the authors observe, this study represents the first scientific experiment to demonstrate that psychological stress influences men’s judgments of women’s body sizes.