Men’s upper-body strength predicts their political opinions on economic redistribution, according to new research published in Psychological Science, a journal of the Association for Psychological Science. The principal investigators of the research — psychological scientists Michael Bang Petersen of Aarhus University, Denmark and Daniel Sznycer of University of California, Santa Barbara — believe that the link may reflect psychological traits that evolved in response to our early ancestral environments and continue to influence behavior today.

“While many think of politics as a modern phenomenon, it has — in a sense — always been with our species,” says Petersen.

In the days of our early ancestors, decisions about the distribution of resources weren’t made in courthouses or legislative offices, but through shows of strength. With this in mind, Petersen, Sznycer and colleagues hypothesized that upper-body strength — a proxy for the ability to physically defend or acquire resources — would predict men’s opinions about the redistribution of wealth. The researchers collected data on bicep size, socioeconomic status, and support for economic redistribution from hundreds of people in the United States, Argentina, and Denmark. In line with their hypotheses, the data revealed that wealthy men with high upper-body strength were less likely to support redistribution, while less wealthy men of the same strength were more likely to support it.

Read more at Psychological Science