In that crucial period before tenure, assistant professors must publish or perish. Co-authoring a paper with a senior faculty member down the hall can make all the difference. But at least for female psychologists, that collaborator tends to be male, even when there are female full professors available, according to a new study. The authors say that the findings may reveal yet another barrier toward women advancing in academia.

The researchers honed in on psychology because of all the scientific fields they examined, it had the highest prevalence of high-ranking women. They surveyed 50 psychology departments at U.S. and Canadian universities. More than other scientific fields, psychology is heading for gender parity, though it’s not there yet. While the gender ratio of assistant professors is almost exactly even, with slightly more females, full-professor males still outnumbered females 2 to 1 in their data.

The researchers surveyed the psychologists’ research publications from 2008 to 2011. Because the study focused on collaborations within departments, they focused only on the 459 papers that had a full professor and one other member of the same department as co-authors. Such collaborations can make all the difference for junior faculty. If they don’t publish major papers within 6 years, they are unlikely to make tenure, which can often spell doom for their academic careers. Then they tallied how many of those collaborations happened between two full professors or across ranks—a full professor co-authoring with an assistant professor—and calculated the gender ratios. Of course, even if collaboration is completely gender-blind, those gender ratios would not be equally split between male-male and male-female pairs, because there are twice as many male full professors and the rate of publication varies between departments. So the team calculated what the expected gender ratios would be if the psychologists in their study were just randomly collaborating with members of their own departments. If the published papers match those expected ratios, then that would indicate that gender does not play a large role in the collaborations of psychologists within their departments.

That’s not what the researchers found. In a 4-year period, female full professors co-authored only 14 papers with female junior faculty members in their departments, half as many as expected, the team reports online today in Current Biology. Female full professors did collaborate as much as expected with female peers in their departments, as well as male junior faculty.

Female academics face several challenges that their male colleagues don’t, says lead author Joyce Benenson, a psychologist at Emmanuel College in Boston (who co-authored the paper with Richard Wrangham, a full professor at Harvard University where Berenson worked previously as junior faculty). “Besides greater investment in child care and lower self-confidence than men, along with discrimination by men towards women—which by the way is present by 3 years of age— women don't obtain the same level of support as men do from [higher ranked] same-sex individuals.” Berenson notes that the difference starts early in development. “From early childhood onwards, girls [more than boys] prefer to interact with one other equal same-sex peer in an exclusive, intensive, intimate relationship. … This means that higher-ranked and lower-ranked girls are avoided and extraneous girls are excluded.”

For some senior female psychologists, the results are worrying. “I remember talking about this with other women my age when I was much younger,” says Linda Bartoshuk, a full professor of psychology at the University of Florida in Gainesville who has seen her share of gender bias among scientists. “Some older women treated us younger women almost worse than some men did,” she says. “We called it the ‘Queen Bee syndrome.’ We saw it as a phenomenon of passing on abuse. Women who had been treated unfairly saw this as some kind of right of passage and felt entitled to pass it on.” The lack of collaboration found in the study may reflect similar attitudes, she says, although it could also be due to female junior faculty approaching senior males preferentially, in spite of help offered from senior women.

“There is a lot of literature on this in organizations where high-status women are disliked by subordinate women,” Benenson says. But so far she has identified only the lack of collaboration among female psychologists across ranks, not the cause. However, the pattern matches the social behaviors of chimpanzees, she says, where the males “interact [more] in groups with differently ranked individuals, and tolerate conflict more readily than females.” Knowing that this pattern holds even among female scientists should be helpful. “Only by increasing awareness of this can women work to overcome what I consider an innate propensity to favor kin, helpful men, and an equal [rank] female best friend.”