Battle Of The Sexes: Male And Female Brains Aren't So Different After All

Using MRI scans, a team of Israeli researchers have found that there really aren't many physical differences between the brains of men and women.

Among his many teachings, Charles Darwin, the father of evolution, claimed the female brain was inferior to the male’s in both size and functionality. For centuries, scientists continued to hold onto the idea the two brains were inherently different. In a new study, however, researchers have finally put this age-old theory to rest, proving that the gender-specific brain is nothing but a myth.

For the study, researchers from Tel Aviv University in Israel analyzed existing sets of MRI brain scans from more than 1,400 men and women in order to identify structural differences between the two sexes. The team specifically looked at differences in the the volume of gray matter, comprised of the neural cells where information processing occurs, and white matter, which comprises the axons that facilitate communication between gray matter regions. In addition, the researchers also studied data from diffusion tensor imaging — a tool that shows how tracts of white matter extend and connect through different regions of the brain, Science Magazine reported.

The team was able to find some structural differences between male and female brains. For example, the hippocampus, an area associated with memory, learning, and emotion, was often larger in men. (An October study, however, found this difference is often overstated and trivial.) To determine which areas were more female than male, and vice versa, the researchers categorized the features based on which gender they appeared in more.

Interestingly, most brains proved to be a “mosaic” mixture of both female and male characteristics. The researchers found that depending on which area of the brain they looked at (gray matter, white matter, or diffusion tensor imaging data), between 23 and 53 percent of brains contained characteristics that were in both the male and female brain. What’s more, between 0 and 8 percent of brains contained only male or only female structures. Based on these results, lead researcher Dr. Daphna Joel concluded, “There is no one type of male brain or female brain,” Science Mag reported.

Joel said the lack of physical differences between the male and female brains’ structures also suggests there may be no difference between how men and women act. Joel and her team investigated this theory by analyzing the personality traits and behaviors of more than 5,500 men and women. In doing so, they concluded that gender specific behaviors — women like scrapbooking and men like video games, for example — tended to be practiced by both sexes.

“There is no sense in talking about male nature and female nature,” Joel said. “There is no one person that has all the male characteristics and another person that has all the female characteristics. Or if they exist they are really, really rare to find.”

These results drive home the idea that we shouldn’t treat people differently because of their gender and moreover, they suggest it’s time for neuroscientists to stop focusing so hard on comparing men’s and women’s brains.

Source: Joel D, Berman Z, Tavor I, Wexler N, et al. Sex beyond the genitalia: The human brain mosaic. PNAS. 2015.