The latest imaging data reveals gender-based differences in the way brain networks are connected.

The study, which was published in the Proceedings of the National Academy of Sciences, included nearly 1,000 young people aged eight to 22 and revealed small differences between girls and boys before puberty that became larger at around age 12 or 13.

That pattern, which remained throughout adulthood, showed that the women’s brains were wired to better integrate emotion and reason— while the men’s brains had stronger links between coordinated action and perception. For men, that translated into brains more highly connected from front to back, so perceptual and action-focused areas enjoyed stronger networks, while women’s brains had more left to right wiring. That matchup strengthened the connections between intuitive and emotional regions with those involved in rationality and planning.

Because most of the changes are established around adolescence, the study’s senior author Ragini Verma, assistant professor of radiology at the University of Pennsylvania says both social and biological factors — from intensifying cultural pressures to conform to gender roles, to hormonal changes, may be involved in the divergent networks.

But which comes first — are biological differences generating the male or female connectivity patterns, or are social gender roles reinforcing specific connections? The study couldn’t say whether men’s better-connected action and perception areas made them superior at mechanical skills or whether more practice at physical tasks requiring dexterity enlarged and improved those regions in the first place. Similarly, women’s apparent advantage at integrating intuition and analysis might give them better social skills— or more socializing might improve those brain regions and create that talent. Given what’s known about how the brain develops, a combination of both practice and biology — in the form of neural networks especially receptive to that type of practice — is likely involved.

Cultural influences are also significant; for example, while girls in the U.S. typically underperform in math compared to boys, in the more egalitarian Scandinavian countries, either no gap, or only small ones exist. Similarly, in rural India, girls from tribes where women have higher status perform better on tests of visual skills important to math than girls from tribes that are more patriarchal.

MORE: The Math Gender Gap: Nurture Trumps Nature

So the findings don’t necessarily mean that women are all emotionally-skilled or that men are always athletically or mathematically inclined. “The researchers’ earlier data shows very clearly just how much overlap there is between the sexes,” says Cordelia Fine, associate professor at the University of Melbourne in Australia and author of Delusions of Gender: How Our Minds, Society and Neurosexism Create Difference, who was not associated with the research. Girls outperform the boys in areas where males are supposed to excel 40% of the time, she says, and vice versa.

But understanding gender differences in brain networks could be critical to studying mental illness and developmental disorders, which often vary by gender and change with age. In autism, as well as in depression and schizophrenia, risk levels, timing and symptoms are highly affected by gender. Even for those unaffected by these disorders, the results could be useful in understanding what makes men and women “think” differently.