A new study has found that girls at same-sex schools feel greater pressure to adhere to gender norms — and were bullied if they didn’t — than those at mixed-gender schools. Perhaps even more surprising, the same researchers say that girls at same-sex schools evaluated their self-worth based more on social confidence than cognitive confidence — while girls at mixed-gender schools weighed academics more heavily than social prowess.

These results contradict a lot of the conventional wisdom that compels some parents to seek out an environment without boys — namely, less romantic drama, greater social acceptance and increased academic confidence. So which is it: Are girls more likely to empower one another or to make Burn Book–worthy comments about those who don’t fit in like in Mean Girls? To find out, we asked the experts.

Some feminists would argue that in the middle-school years (the girls in this study were fourth-, fifth- and sixth-graders), boys pressure girls to fulfill certain gender norms. But William M. Bukowski, one of the researchers in the girls-school study and the director for the Center of Research in Human Development at Concordia University in Montreal, argues that boys aren’t imposing stereotypes on girls — girls are imposing stereotypes on each other. “It’s called the social-dosage hypothesis,” Bukowski says. “When girls are together without the presence of boys, they’re going to get an extra-strong dose of what it is to be female.” Hence, girls at the same-sex school feel more pressure to be “girly.” Why those same girls might value their social competence over their academic competence Bukowski couldn’t explain.