An analysis of more than 14 million reviews on RateMyProfessors.com, where students write anonymous reviews of their professors, found that students most often use the words "brilliant" and "genius" to describe male professors and in academic disciplines in which women and African-Americans are underrepresented.

The findings, reported in the journal PLOS ONE, included academic disciplines in the sciences, humanities, social sciences and math.

"Male professors were described more often as 'brilliant' and 'genius' than female professors in every single field we studied—about two to three times more often," said University of Illinois graduate student Daniel Storage, who led the study with U. of I. psychology professor Andrei Cimpian. Princeton University philosophy professor Sarah-Jane Leslie and U. of I. graduate student Zachary Horne also contributed to the research.

Students also used "brilliant" and "genius" to describe their professors most often in academic fields such as philosophy and physics, in which women and African-American students are a distinct minority, Storage said.

The new findings mirror those of a 2015 study led by Cimpian and Leslie and published in Science. In that study, the researchers asked graduate students, researchers and faculty members to name the qualities that were most conducive to success in their fields. The 2015 analysis found that survey participants who emphasized brilliance or genius as a precursor to success were more likely to belong to academic disciplines where women and African-Americans were underrepresented.

The new analysis reinforces the previous one and offers new insights into students' attitudes and thoughts, the researchers said.

"What's valuable about spontaneous comments is that they provide an unvarnished reflection of how people evaluate others in their field, and what they look for in other people in that field," Cimpian said.

In the 2015 study, the researchers tested several alternative hypotheses to explain why some disciplines have so few practitioners who are female or African-American. But none of the hypotheses could explain the phenomenon as well as the belief that brilliance or genius was necessary for success in those fields, Cimpian said.

The new study also found that none of the following four factors could fully explain the underrepresentation of women or African-Americans in a field: average GRE (graduate school entry exam) math scores, the desire to avoid long hours at work, the selectivity of each field or the ability to think systematically. While there are correlations between some of these factors and the presence or absence of women and African-Americans in some fields, "we consistently found that the only thing that was explaining the proportions of women and African-Americans in a particular field was that field's emphasis on the importance of brilliance and ," Storage said.

"Both of these groups are stereotyped in a similar way about their intellectual abilities and therefore are potentially affected in a similar way by the amount of emphasis that's put on brilliance," Cimpian said. "The people in certain fields might not see that quality in women and African-Americans. Women and African-Americans themselves may be conditioned to not see these qualities in themselves."

Journal information: PLoS ONE , Science