It's long been a popular stereotype: Men are hugely competitive, meaning cooperative effort is the exception rather than the norm, while women have a tendency to nurture relationships with others, making them much more likely to cooperate with one another. A new Harvard study, however, is turning that cliché（陈词滥调） on its head.

In fact, within academic departments women of different social or professional "ranks" cooperate with each other less well than men do, according to Joyce Benenson, an Associate of Harvard's Human Evolutionary Biology Department and Professor of Psychology at Emmanuel College, Richard Wrangham, the Ruth Moore Professor of Biological Anthropology and Henry Markovits, from the University of Quebec at Montreal, the study's co-authors. With full professors of the same sex, they said, the study found men and women cooperated equally well. The study is described in a March 3 paper published in Current Biology.

"The question we wanted to examine was: Do men or women cooperate better with members of their own sex?" Wrangham said. "The conventional wisdom is that women cooperate more easily, but when you look at how armies or sports teams function, there is evidence that men are better at cooperating in some ways. Because there is so much conventional wisdom and general impressions on these issues, I think it's helpful for this paper to focus on a very clear result, which has to do with the differences in cooperation when rank is involved."

To get at whether -- and why -- those differences in cooperation might exist, Benenson and Wrangham set out to understand how often faculty at dozens of universities collaborate on academic papers.

They began by identifying 50 institutions from across the U.S. and Canada with at least two male and female full professors, and two male and female assistant professors in their Psychology Departments. Researchers then set about identifying papers written by senior faculty from 2008 to 2012, and tracking how often senior faculty worked with other senior faculty, and how often they worked with junior faculty.

While the study focused on the world of higher education, Benenson explained that the notion of differences between how men and women cooperate was first planted during her work studying children.

"When I studied young children, I noticed that boys were typically interacting in groups, and girls tended to focus on one-on-one relationships," said Benenson, the study's lead author, who explored similar questions in her book Warriors and Worriers. "There is even evidence that these differences exist in six-month-olds -- but you can see it with the naked eye by about five or six years old, where boys form these large, loose groups, and girls tend to pair off into more intense, close friendships."