Girls in gender equal societies not only perform better in studies but can also outperform boys, a major international research shows.
High school boys outscored girls in standardized math tests in the United States. But girls performed just as well as their male counterparts in Norway, Sweden, and other countries with the most economic equality, according to researchers from Northwestern University.
But girls outscored boys in reading across all 40 countries the team studied.
Researchers looked at the results of a standardised international exam taken by more than 270,000 15-year-olds from 40 countries in 2003.
"The so-called gender gap in maths skills seems to be at least partially correlated to environmental factors," said Prof Paola Sapienza, from the Kellogg School of Management at Northwestern University, Illinois, one of the lead researchers.
"The gap doesn't exist in countries in which men and women have access to similar opportunities."
The Programme for International Student Assessment is designed to be culturally unbiased, said Professor Paola Sapienza.
She and her colleagues noticed that while boys overall did better on the math part of the test, girls did as well or slightly better than boys in Northern Europe. To Sapienza, who grew up in Italy, it suggested a cultural pattern.
To see if there was a connection to gender equality, she used something called Gender Gap Index, a measurement of access to education and well-paying jobs collected by the World Economic Forum. In that index, the United States ranks 16th, behind Australia, Canada, New Zealand, and a handful of European countries.
With perfect equality being a 1, she said, Sweden scores .81, the United States .70, and Italy .64.
As another measure of gender status, she also looked at the Worldwide Values Survey, which canvassed people with questions such as "Do you think university education is more for boys than girls?" and "Do you think women working outside the home are not taking good care of their children?"
Attitudes about gender and economic equality ran parallel to girls' high math scores, she said.
But in a twist, the countries that showed the most economic equality had the biggest gaps in reading scores, with the boys lagging. "It's a factor I find intriguing," she said.
But even in those countries, the high scores of the girls didn't come at the expense of the boys - both sexes scored relatively high compared with the other countries.
Sapienza said the study did not claim to uncover why economic and attitudinal equality are linked to test scores. And while it does suggest that culture plays a role in math performance, that doesn't eliminate the possible influence of biology.
Certain patterns held true across countries, she said. The average girl, for example, did better in arithmetic than geometry, and better on reading than in math. For the average boy, it was the reverse.
The findings, published in a recent issue of the journal Science offer new insights to a raging debate over gender differences in learning, the relative roles of culture and brain biology, and the question of whether boys or girls are being shortchanged by the school system.
Recent results have also shown that girls are starting to outperform boys in maths at GCSE level, but Dr Jeremy Hodgen, a lecturer in mathematics education at King's College London and secretary of the British Society for Research into Learning Mathematics, said there was still a problem in encouraging girls to continue studying the subject past a certain age.
He said: "Although they do well at GCSE, we do find a lack of girls who keep on studying maths after the age of 16. There needs to be more done to make the subject attractive to them and to ensure that they are not discouraged from a career in mathematics just because of their gender."
Dr Hodgen added that research had shown that streaming pupils benefited high-performing boys more than high-performing girls, suggesting that female students felt alienated by some classroom environments.
The new findings don't change the basic differences in the male and female brains, said Michael Gurian, a US family therapist and author of Boys and Girls Learn Differently
and other books on gender. "Those brain differences allow men to outperform women, on average, only in certain areas of math that involve spatial reasoning and symbolic thinking," he argued in an interview to Philadelphia Inquirer.
He felt the study would have done better to separate arithmetic, where girls perform as well as boys, and what he calls "iconic and symbolic math," where boys tend to outperform girls. "It's there that the real difference is."
And that gap, he said, is due to brain differences that should be addressed in education. He acknowledged that some boys and some girls perform at the top in any field. But on average, he said, boys will have more trouble when faced with a blank page and told to write an essay.
Students who tend to be spatial thinkers - most of them male, he said - tend to write better if asked to create a drawing first to sketch out their thoughts.
Likewise, the more verbally oriented students - usually girls - can improve their math performance if asked to talk over a problem before solving it.
"We're trying to make education more diverse," he said. But overall, he said, the system is skewed toward females, thus leading to a preponderance of girls going to college.
Peter Kuriloff, a professor at the University of Pennsylvania's Graduate School of Education, says gender differences in learning are tiny compared with the differences between individual boys and girls.
And he's not convinced there's any serious discrimination against boys outside of class and racial discrimination.
All of the focus on anti-male discrimination "masks the really important stuff that's going on," he said. If you look at African American boys, 25 percent end up in jail - that is a crisis."
As for brain differences, he said, not that much is known about the connection with learning, "but there's a lot of malarkey."
In his experience, girls may be getting better grades and graduating from college in greater numbers because they're working harder than boys. "Every time you've given girls a chance, they've done better than boys in school," he said. "There's been a push to put them back in a box."