Testosterone, the hormone that creates brawn also causes men to be less generous, concludes a new study led by visiting professor Karen Redwine, a neuro-economist.
"Our broad conclusion is that testosterone causes men essentially to be stingy," says Redwine, who presented the work at the Society for Neuroscience's annual meeting in Chicago last week.
A previous study of 17 London traders found that morning testosterone levels correlated with each day's gains and losses, with more of the hormone associated with a profit. But that study didn't establish a cause-effect relationship between testosterone and shrewdness.
To make this case, Redwine and her colleague Paul Zak, at Claremont Graduate University, gave a testosterone-containing gel to 25 male university students, and then tested their generosity. All the participants also got a placebo cream with no testosterone, either a few days before or after the testosterone boost. Neither the researchers nor the participants knew which was which until the end of the study.The research was originally reported in New Scientist.