When it comes to demographics and society, no one likes surveys and statistics that make them look less positive. Yet surveys and statistics are all we have to go by in order to know if people are treating each other the way they expect to be treated in turn.

In society, there is a belief that women will be more cooperative than men. In academia, that is not the case, according to a paper in Current Biology. Instead, women in academia are less likely to cooperate than men.

The findings are based on an analysis of the publication records of professors working at 50 North American universities.And the lack of cooperation is most evident in an area where women overwhelmingly dominate - psychology.

"People are often upset to hear evidence of sex differences in behavior," says Joyce Benenson of Harvard University. "But the more we know, the more easily we can promote a fair society."

Males cooperate more in nature also, such as we see among other primates. To explore these dynamics in humans, Benenson and colleagues looked to academia, because it had the basic information they needed — individual rank, evidence of mutual investment, and a baseline number of males and females — which is less easy to find about the military, government, or business. Female professors are still underrepresented in areas of science like chemistry and physics (and to some extent in biology) so they went where they had ample data - psychology departments.

Using numbers of co-authored, peer-reviewed publications as an objective measure of cooperation and professorial status as a measure of rank, the researchers calculated the likelihood of co-authorship with respect to the number of available professors in the same department. Their calculations showed no difference between men and women at all among individuals of equal rank.

Yet male full professors were much more likely than female full professors to co-author publications with a same-gender assistant professor, which is a lower rank. In other words, differences in rank didn't get in the way of cooperation amongst men in the way that it did for women.

Benenson says they are planning a number of follow-up analyses to find out if men in psychology are underrepresented yet somehow still prevent women from cooperating more. Or if women simply fail when they attempt cooperation. Is the reluctance to cooperate driven from above or below? And what would encourage women to reach out and cooperate more?

The bottom line for now, they say, is this: "In ordinary life we often think of women as being more cooperative and friendly with each other than men are, but this is not true when hierarchy enters the picture," Benenson says.

Citation: Joyce F. Benenson, Henry Markovits, Richard Wrangham, 'Rank influences human sex differences in dyadic cooperation', Current Biology 24(5) pp. R190 - R191 3 March 2014 doi:10.1016/j.cub.2013.12.047