American boys, overall, show less self-control than American girls, but this kind of gender gap doesn’t appear to exist among children in certain Asian countries, according to new research published in Early Childhood Research Quarterly.

Shannon Wanless, lead author of the study, and colleagues examined the behavioral traits of 814 children ages 3 to 6 in the U.S., Taiwan, South Korea, and China.

They found that American girls showed better self-control—following directions, staying on task, and controlling behavior and impulses—than American boys, but that children in the Asian countries showed no such gender-based differences.

“We know from previous research that many Asian children outperform American children in academic achievement,” Megan McClelland, an associate professor at Oregon State University who oversaw the research, said in a press release. “Increasingly, we are seeing that there is also a gap when it comes to their ability to control their behavior and persist with tasks.”

Researchers also said they found something surprising: when children were directly assessed using various school-readiness tasks, there were no differences between the boys and girls, but some teachers perceived girls as better at self-regulation, even when they performed at the same level as boys.

“In general, there is more tolerance for active play in boys than in girls,” McClelland said. “Girls are expected to be quiet and not make a fuss. This expectation may be coloring some teachers’ perceptions.”

Wanless said that self-regulation is important for academic performance for both boys and girls. Self-regulatory development should be supported for all children, especially boys, she said.

“Low self-regulation in preschool has been linked to difficulties in adulthood, so increased focus on supporting young boys’ development can have long-term positive benefits,” Wanless said.

Teacher perceptions of gender roles in the classroom are important because research from earlier this year says the “boys-will-be-boys” mentality may be hindering boys’ academic achievement.