Intergenerational transmission of gender bias and the gender gap in STEM

More male students than female students choose to study STEM subjects (and economics) at university. In a recent post, I discussed two papers that could be interpreted as suggesting comparative advantage as an explanation. That is:

...even though female students may be better than male students in STEM subjects at school, we may see fewer of them studying those subjects at university (let alone taking them as a career), because female students are also better in non-STEM subjects at school, and they are better by more in non-STEM than in STEM, compared with male students. Economists refer to this as the students following their comparative advantage. Female students have a comparative advantage in non-STEM, and male students have a comparative advantage in STEM subjects.

However, there are other competing explanations. Students' choices are affected by their parents and by their peers. So, if their parents hold biased views about whether studying a STEM subject is suitable for female students (or if their peers do), then female students may be less likely to study STEM subjects. A recent working paper by Alex Eble (Columbia University) and Feng Hu (University of Science and Technology Beijing) looks specifically at the intergenerational transmission of bias (from parents to children).

Eble and Hu use data from 8,912 Chinese students in 215 seventh and ninth grade classrooms, who were routinely randomly assigned to classrooms. That means that each student's peer group (within their classroom) was randomly assigned. The key variables that Eble and Hu are interested in are the bias in the views of each student's own parents, and similar bias in the views of each student's peers' parents. They then look at how those two biases are related to students' own bias, aspirations, and academic performance. They find that:

...a one standard deviation increase in peer parents’ bias causes a 4.2 percentage point (8%) increase in the likelihood that a child will hold the bias... This transmission of bias appears to occur for both girls and boys in roughly the same manner... we calculate that going from roughly 25 percent of peers’ parents being biased to 75 percent of peers’ parents being biased generates an 18.9 percentage point (34%) change in the likelihood that a child will also hold that bias...

Children whose parents hold anti-girl bias are 29 percentage points (52%) more likely to also hold that bias, and again the transmission appears to hold equally for boys and for girls...

Ok, so there is intergenerational transmission of bias. How does that affect the gender gap? Eble and Hu find that:

...an increase in peer parent bias increases the gender gap... in girls’ perceived difficulty of math relative to boys’ by two percentage points, or 28 percent of the 7.2 percentage point gap between boys and girls in this variable. This pattern also holds for own parents’ bias, and the estimates are again more stark: our estimated coefficient of own parent’s bias on the gender gap is a 15.0 percentage point increase in the likelihood that a girl perceives math to be difficult, relative to the likelihood for boys. For boys, own parent’s bias is associated with a 6.1 percentage point decrease in the likelihood the child will perceive math to be difficult; the “total effect” for girls is an 8.9 percentage point increase in this likelihood...

As with perceived difficulty, our estimates of the effect of peer parents’ bias on boys’ and girls’ test scores, respectively, differ in sign. Boys appear to gain slightly (a statistically insignificant 0.05 SD increase) from a one standard deviation increase in the proportion of peers whose parents believe that boys are superior to girls in learning math. For girls, on the other hand, we estimate that a one SD increase in peer parent bias increases the gender gap - that is, reduces girls’ performance relative to boys’ - by a statistically significant 0.063 SD...

Here again the correlation between own parent’s bias and performance is much larger in magnitude - the scores of boys whose parents believe that boys are better than girls at learning math are 0.16 SD higher than for boys whose parents do not believe this, and for girls, having a parent who holds this bias pushes the child’s test score down, relative to boys’ scores, by 0.28 SD...

In other words, they find evidence that the gender gap in perceived difficulty of maths and in maths test scores can be partially explained by own parents' bias and peer parents' bias. Unsurprisingly, the effect of own parents' bias is the larger of the two. Interestingly, they also find that girl peers' parents have a bigger effect on girls than boy peers' parents do. However, in amongst the results they also find a potential partial solution, at least in terms of peer parents' bias:

These negative effects, however, decrease with the number of friends the child has in her class; a child with five close friends in her class appears to be entirely immune to the negative effects of peer parent bias that we have shown throughout this study...

So, it's not all bad news. If you want to give your daughter the best chance for success in STEM, start by minimising the bias in your own views. If you're worried about the biased views of other parents, to the extent you can you should make sure your daughter has many close friends in her class.

[HT: Development Impact]