A US study has found that researchers assessing the employability of early-career scientists subconsciously favour male students over females. The bias, which was seen to exist in both male and female physicists and was also exhibited by chemists and biologists, is thought to be a contributing factor towards the underrepresentation of women in physics.

Undertaken by psychologist Corinne Moss-Racusin and colleagues from Yale University, the study involved 127 tenured scientists across six universities in the US being asked to provide feedback on an excerpt from a job application for a graduate-level lab-technician post at another institution. The excerpt – developed by an academic panel – was designed to be as realistic as possible and was identical, except that 64 of the scientists were told the applicant's name was Jennifer, while the other 63 were told the applicant's name was John. The scientists were told that their feedback would help the applicant's career development, unaware that both the candidate and the post were fictitious. The candidate was painted as promising but not exceptional.

The study found not only that the scientists rated the male applicant as significantly more competent and hireable than the (identical) female applicant, but also that the hirers would have given the male student a higher starting salary. "Male and female science-faculty members, including physicists, said they were more likely to hire the male student," says Moss-Racusin. "They also offered to pay him about $4000 more per year on average and were more likely to offer him career mentoring, relative to the identical female student."

Innate nature

The bias shown by the potential hirers was independent of their gender, age and seniority, indicating that even women show a subconscious bias against other women. The innate nature of the bias is thought to be evidence of the influence of a society-wide stereotype that men make more competent scientists, influencing even "very well meaning, very well trained scientists who emphasize objectivity and egalitarianism in their daily lives", according to Moss-Racusin.

Amy Graves, a physicist from Swarthmore College, near Philadelphia, who specializes in gender studies in science, says she is "saddened, but not surprised" by the findings. "This study is so well done, because they created a résumé that was good, but not amazing," says Graves. "If [the candidate] were an absolute standout, prior studies suggest that [the authors of the study] might not have seen this evidence of a genuine, unconscious bias."

Mentoring needed

According to Moss-Racusin, having structured and transparent mentoring is one solution to the problem. She recommends guidelines to help standardize support across all students and the use of secondary mentors. "One of the biggest predictors of success and retention within academia, especially for women and racial-minority students, is identifying with a role model or a good mentor."

Meanwhile, a pilot mentoring programme – Women in Technology Sharing Online – was launched last month by the Piazza online education platform and by Harvey Mudd College in Claremont, California. By introducing female students to mentoring, the sponsors hope to increase the retention of women in science.

The results are published in the Proceedings of the National Academy of Science.