Why men with older sisters may be less competitive

In general, research suggests that men are more likely than women to put themselves in competitive environments.

That difference might at least partially explain why men are overrepresented in top management.

Yet a new study finds that men with older sisters are significantly less inclined to compete compared to men without siblings. On the other hand, women with younger brothers are slightly more likely to compete compared to women without siblings.

The researchers say these findings suggest that putting women in situations where they're more powerful than younger men could encourage those women to enter other competitive environments.

To test this phenomenon, the researchers conducted two experiments. In one, high-school students were asked to complete a maze challenge or a math test. They chose whether they would prefer to be paid for participating under a piece-rate payment system (earning money for each correct answer) or a tournament system, with the opportunity to earn a larger sum if they beat the other people in their group.

Results showed that boys chose to enter the tournament system more often than girls (61% versus 23%). Yet the researchers found that men with older sisters only chose the tournament option 38% of the time. Meanwhile, women who had younger brothers chose the tournament setup at a 39% rate.

In the second study, university students completed math problems, and men with older sisters were 21% less likely to enter the tournament than other men.

One potential explanation for these results is that younger brothers may assimilate the stereotypically feminine traits of their older sisters, such as kindness and friendliness. Another is that older siblings typically assume the more competitive role, possibly because in the past, they had to defend their resources from the younger interlopers.

Hiroko Okudaira, Ph.D., a professor at Okayama University in Japan and the study's lead author, said these findings probably apply to older adults as well.

And while it's hard to say for sure, she thinks the results could imply that men with older sisters are less competitive in business contexts. For example, they might be less likely than other men to gun for promotions and raises at work.

Ultimately, the researchers write, "our study lends support for institutional reforms that promote interactions between women and younger men. Exposing women to experiences where they are in a position to overrule younger men may help cultivate their willingness to compete with men."

The idea isn't to discourage men from competing so much as to encourage women. It's an interesting suggestion because it doesn't involve demanding that anyone change his or her personality, so much as tweaking the environment to bring out different aspects of their personalities in the workplace.