SUCCESSFUL financial traders may be born, not made. Men who excel at fast-paced financial trading may have been exposed to higher levels of testosterone in the uterus than their less successful colleagues.
Last year, John Coates at the University of Cambridge and colleagues found that traders who started the day with elevated testosterone made more money than those who didn鈥檛. He wondered whether another effect could also contribute: individuals who had higher exposure to testosterone in the uterus are more likely to feel the effects of the hormone in later life.
Coates recruited 49 male 鈥渉igh-frequency鈥� traders from the City of London, who buy and sell over the space of minutes or seconds, requiring high levels of confidence and quick reaction times. He measured their index to ring finger ratio 鈥� thought by many researchers to be a marker of prenatal testosterone exposure.
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Traders with a longer ring finger, and therefore higher prenatal testosterone, made on average six times the profits of traders with shorter ring fingers, and tended to remain traders for longer (Proceedings of the National Academy of Sciences, ).
The study confirms that exposure to sex hormones early in life enables particular behaviours to develop, says Bruce McEwen of the Rockefeller University in New York, but adds that other factors no doubt play a role in success in this particular career.
Coates agrees, and cautions against bosses using finger length to make hiring decisions. The effects of high prenatal testosterone may even be a disadvantage in other types of trading. For example, other studies have suggested that people with a high index to ring finger ratio make better mathematicians. John Manning, author of The Finger Book, wonders whether finger ratios might turn out to correlate with success in other professions.