The series of studies looked at 34 men and 36 women who were told to complete a task that would be completed independently but would be judged on the group performance of a partner they were "paired" with. In the first study, each individual task was identical. Each participant was paired with a fictional teammate of the opposite sex he or she believed to be real. Participants were then given 20 minutes to complete a task and a job description for the "male-sex typed" role, which indicated 89 percent of people filling that role were men. Individuals then received feedback, half of which was presented as "individual" feedback and half of which was presented as "group" feedback, that said the group had earned an "excellent" rating. Participants were then given a questionnaire to fill out that inquired about the individual performance, the partner's performance, and the individual's contribution to success. The women who were given group performance indicated their partner had a great contribution to success.

In the second study, half of participants ran the same study, but this time half were told that the task each person was asked to complete was different from his or her "partner," so it was clear whose work was whose. In this scenario, women rated their individual contributions much closer to that of their male "partners."

In the third version of the study, the researchers varied the sex of the fictional partner. Women paired with a "female partner" actually gave themselves higher ratings than their teammates.

In the fourth scenario, they tried to prime participants' expectations by giving them a "pretest" for the task, to which half received positive feedback and half didn't receive any feedback. In this version, women who received no feedback before starting the task chose their teammate as the better performer. Those who received positive feedback were much more likely to take credit for their work, something the researchers said "undercut" the participants' negative expectations.

While Haynes' research reveals that women are less prone to deflecting credit when they work with other women, the solution probably isn't just to encourage people to work in gender-segregated groups.

"I'm not sure that just siphoning people off by gender works," Haynes said. "And in the long term, it might reinforce the nature of the process."

This difficult choice plays out in the real world. Emily Williamson is a former health care professional turned web developer who works with Rails Girls Washington DC. The group hosts regular hacker-style events aimed at teaching women to code in an open-source web framework called Ruby on Rails. She says, "I would say that in general, when I see women in a group, they tend to associate with 'we' more than 'I.' They definitely showcase themselves a lot less."