Aug. 25, 2009— -- Women often look back on mentors, family members or teachers as influences in their career decisions. But a new study found something as simple as testosterone levels may be nudging women into one career path over another.
A new study of 500 graduate business students showed that women with higher testosterone levels take more risks and are more likely to choose a finance career than women with low testosterone levels.
But testosterone levels made no difference in men's career choices in the study.
Researchers at the University of Chicago and Northwestern University tested testosterone's effect on career choice among MBA students, in part to shed light on an ongoing debate about whether social or biological influences lead more men into high-risk careers in finance.
"While it is true that the social environment can influence career decisions a lot, it is true, genetically, that women have lower testosterone than men, on average," said Luigi Zingales, a professor at the University of Chicago Booth School of Business and a lead author of the study published Monday in the Proceedings of the National Academy of Sciences.
Citing his results, Zingales said "there is no way to say this is nature, or this is nurture." But, he said, the study helps to shed some light on how much, and when, biology plays a part in business career choices.
To test testosterone's influence, the researchers recruited 500 master's students at the University of Chicago Booth School of Business to participate in a series experiments.
The men and women volunteers gave saliva samples to measure testosterone levels. (Women typically have lower testosterone levels in their saliva than men, but not always.) The volunteers then played a risk-taking game that is often used to predict how much risk a person would take while investing in the stock market.
After graduation, the researchers compared the results of the saliva test, the students' career choices, and a few other measurements that loosely mark how much testosterone the person was exposed to as a fetus, including the ratio of the index-finger length to the ring-finger length.
Eventually, 36 percent of female students chose high-risk financial careers, compared to 57 percent of male students.
Testosterone's Influence on Career Choice May Be Small
Overall, the researchers found that in women, not men, the amount of testosterone in the saliva was linked to a choice of a high-risk career -- but not by much. Zingales guessed that after a certain peak of testosterone, the hormone stopped influencing risk-taking tendencies in the brain.
Other measurements such as the finger-length ration had little significant effect on the career choice.
Dwayne Hamson, a researcher who studied the effects of hormones on the brain in the Breedlove Jordan Lab at Michigan State University, pointed out that given all other factors, testosterone only explained 5 percent of the difference in the results of the risk-taking game.
"To look at this another way, fully 94 percent of the relationship between risk aversion and testosterone levels is explained by something else ... some other variable," he said.
Indeed, even Zingales wanted more studies into the matter -- especially because testosterone levels tend to change with lifestyle.
"There are lifestyle factors that permanently increase or decrease testosterone," Zingales said. "For example, married men tend to have a lower level of testosterone than unmarried men."
"An interesting further study would be to look at either men or women who are treated with testosterone for medical reasons and see if they change their risk aversion," Zingales said.
But the science lands on the nature versus nurture debate, as a growing group of financial experts are calling for more risk-adverse women to get into the financial trading scene.
"The financial world is predominantly young males -- if you have one section of the population isolated, you tend to get extreme behavior," said John Coates of the Judge Business School and department of physiology, development, and neuroscience at the University of Cambridge, England.
Do We Still Want Risk-Takers on Wall Street?
"I think it's important, when looking at hormones and finance, to not equate finance with a single trait; like risk, for example," Coates said.
Although the business world tends to reward short-term, high-risk traders more than successful long-term analysts (whose ranks tend to be more women than men), Coates and others say that might be the reason why the world economy is down the tubes.
"I do think, generally speaking, women are more risk adverse," said Stephanie Hauge, president of the Financial Women's Association in New York City. "But I think in a business environment, it's good to have a balance.
"I think what happened in the environment we're all recovering from is we had a huge proponent on the risk side and not enough on the risk-adverse side."
Regina Barr of the board of directors of Financial Women International said, traditionally, female attributes could contribute to whether most women were "risk adverse."
"If you look at the industry as a whole, I think that banking and financial services are relationship-oriented and women are very relationship-oriented," Barr said. "I think there is a ton of opportunity for women."