Past research has shown that winning and losing in sports matches and other competitions affect testosterone levels in men. The new findings, published online October 21 by PLoS ONE, reveal that politics can influence testosterone in men “just as if they directly engaged head to head in a contest for dominance,” says Kevin LaBar of Duke, the study’s senior researcher.

In separate work, anthropologist Coren Apicella of Harvard University and her colleagues obtained similar results with a smaller group, findings they will publish this year. “It’s an exciting time for people who study political behavior, where biological factors have largely been ignored,” she notes. “Political scientists are starting to recognize the role of biology, and more and more research is showing there may be some reciprocal interactions between how elections make one feel and how feelings can affect political behavior.”