Women's and men's brains are wired differently, in ways that seem to match the stereotypes. The finding comes from a method of visualizing brain connections, although it doesn't give an idea of how the differences initially arose.
Ragini Verma at the University of Pennsylvania and colleagues scanned the brains of 949 people ages 8 to 22. They focused on two regions: the cortex, involved in thought, perception and language; and the cerebellum, which coordinates movement. Their method tracks the motion of water molecules to show where nerves stop and start, revealing what is known as the connectome.
The left and right hemispheres of the cortex were much more connected with each other in females than in males. But in males, each cerebellum had more links to the cortex on the opposite side of the brain than females. This favors connections that promote coordinated movement, which males can generally do faster in tests.
The cortical linkup in females would promote communication between areas involved in analytical and verbal tasks and those for spatial and intuitive processing, the team says. Among other things, this might reflect a superior ability to process emotions and understand others' intentions.
The way the findings have been analyzed so far, Verma says, shows how males and females as a whole differ. "We identified differences that survive rigorous mathematical and statistical analysis in a population."
Now, the researchers want to find out whether individual male and female brains within those populations always differ along these lines, or whether there is a range of variations in which the sexes overlap. This should also show which networks men and women always share, and whether any are always sex-specific.