A new study concludes that testosterone causes men essentially to be stingy.
According to the study, the hormone which makes men big and beefy also reduces their generosity.
Karen Redwine, a neuro-economist at Whittier College in California, presented the work at the Society for Neuroscience's annual meeting in Chicago last week.
To reach the conclusion, Redwine and her colleague Paul Zak, at the Claremont Graduate University in California, gave a testosterone-containing gel to 25 male university students, reports New Scientist.
They then tested their generosity.
All the participants also got a placebo cream with no testosterone. Neither the researchers nor the participants knew which was which until the end of the study.
After analyzes, it was found that the testosterone cream worked.
The next day, twice as much of the potent sex hormone coursed through the veins of volunteers, on average.
The students then played a simple economic game with another participant via a computer. Each volunteer played the game in both roles, on and off the testosterone gel.
On the whole, the testosterone cream caused a 27 per cent reduction in the generosity of the offers, Redwine and Zak found.
A more potent variant of testosterone, dihydrotestosterone (DHT), exerted an even stronger influence on behavior, the study found.