Female elementary school teachers who are anxious about math pass on their fears to the girls that they teach.
While this raises the question as to why people who are nervous about math are teaching it in the first place, it may explain why girls often have the idea that math is a 'boy's subject'.
The findings are the product of a study of 17 first- and second-grade teachers and their classes. The researchers found that boys' math performance was not related to their teacher's math anxiety while girls' math achievement was.
"Having a highly math-anxious female teacher may push girls to confirm the stereotype that they are not as good as boys at math, which in turn, affects girls' math achievement," said Sian Beilock, Associate Professor in Psychology at the University of Chicago.
The researchers assessed teachers' anxiety about math. Then, at both the beginning and end of the school year, they tested the students' level of mathematics achievement. They also examined the gender stereotypes the kids held by asking them to draw a picture of a student who was good at mathematics and one who was good at reading.
At the beginning of the school year, math achievement was unrelated to their teacher's anxieties in both boys and girls. By the end of the year, however, the more anxious teachers were about math, the more likely girls - but not boys - were to endorse the view that 'boys are good at math and girls are good at reading'.
Girls who believed this did significantly worse on math achievement measures at the end of the school year than those who didn't.
More than 90 percent of elementary school teachers in the country are women - and they can get their teaching certificates with very little mathematics preparation, according to the National Survey of Science and Mathematics Education.
The authors suggest, unsurprisingly, that the results have implications for teacher training.