Why do men think other men are more intelligent?

Anthropologist Dan Grunspan was studying the habits of undergraduates when he noticed a persistent trend: Male students assumed their male classmates knew more about course material than female students — even if the young women earned better grades.

“The pattern just screamed at me,” he said.

So, Grunspan and his colleagues at the University of Washington and elsewhere decided to quantify the degree of this gender bias in the classroom.

After surveying roughly 1,700 students across three biology courses, they found young men consistently gave each other more credit than they awarded to their just-as-savvy female classmates.

Men over-ranked their peers by three-quarters of a GPA point, according to the study, published this month in the journal PLOS ONE. In other words, if Johnny and Susie both had A's, they’d receive equal applause from female students — but Susie would register as a B student in the eyes of her male peers, and Johnny would look like a rock star.

“Something under the conscious is going on,” Grunspan said. “For 18 years, these [young men] have been socialized to have this bias.”

Being male, he added, “is some kind of boost.” At least in the eyes of other men.

The surveys asked each student to “nominate” their most knowledgeable classmates at three points during the school year. Who best knew the subject? Who were the high achievers?

To illustrate the resulting peer-perception gap, researchers compared the importance student grades had on winning a nomination to the weight of the gender bias. The typical student received 1.2 nominations, with men averaging 1.3 and women averaging 1.1.

Female students gave other female students a recognition “boost” equivalent to a GPA bump of 0.04 — too tiny to indicate any gender preference, Grunspan said. Male students, however, awarded fellow male students a recognition boost equivalent to a GPA increase of 0.76.

"On this scale," the report asserted, "the male nominators’ gender bias is 19 times the size of the female nominators’."

Classroom “celebrities” -- defined in the study as the students with the most classmate recognition -- were overwhelmingly male. Men dominated the top three slots in all three classes, while women peaked at No. 4.

In one class, the most renowned man, so to speak, garnered 52 nominations, while the most renowned woman snagged nine.

The researchers also surveyed the instructors on which students spoke up most in the lecture halls, which could accommodate up to 700 students. Increased male visibility, they figured, could lead to increased male recognition.

Men did raise their hands more often, at least in the instructor's memory. But after controlling for variations in grades and participation, male students still received more recognition from other men than their female peers did.

The phenomenon leads to more than a knowing female eye roll, the report's authors wrote. College women in STEM programs ditch their majors earlier and more often than male students. That's one reason STEM fields remain male-dominated.

Grunspan said reinforcement from faculty members and peers is enormously important to a young person’s education and career development. A simple “You can do this,” for both men and women, could mean the difference between pushing through adversity or giving up.

If a female student's talent is ignored or unnoticed in other classes, “it adds up,” Grunspan said. “What does that mean for the entire collegiate experience for women in STEM?”

The study, he said, should be a warning. Today's students will grow up. They will make hiring and promotion decisions. They will shape policy.

Wrote the researchers: “Our work implies that the chilly environment for women may not be going away any time soon.”