Former California Governor Arnold Schwarzenegger once famously called liberal opponents “girlie men”—and the Obama Administration was ridiculed for a healthcare ad depicting “pajama boy,” a skinny liberal manchild wearing a onesie while drinking cocoa.

But, according to a recent study by Brunel University, they might be on to something: physically weak men are more likely to be socialists.

Brunel studied 171 men, looking at their height, weight, general physical strength, and bicep circumference. They then contrasted their physical data with each man’s views on economic issues: the distribution of wealth, and income inequality.

Brunel found that men who were physically weak were significantly more likely to be socialists.

Interestingly enough, Brunel’s Dr. Michael Price, who led the study, thinks this may be tied to evolutionary biology.

“This is about our Stone Age brains, in a modern society,” he explained. “Our minds evolved in environments where strength was a big determinant of success. If you find yourself in a body not threatened by other males, if you feel you can win competitions for status, then maybe you start thinking inequality is pretty good.”

When Price factored in time spent at the gym, he found that the correlation disappeared—meaning that, rather than being based on natural strength, men who go to the gym are more likely to be capitalists.

Price was quick to note that the findings aren’t “rational in modern environments,” where physical strength rarely determines professional success. But, based on basic biology, it’s clear that more physically powerful men prefer capitalism.