CANADA: Do you have a male brain or a female brain? The answer, according to science, is no. If you didn’t expect this to be a yes-or-no question, you’re not alone. Male brains do seem to be built differently than female brains. An analysis of more than 100 studies found that the volume of a man’s brain is 8% to 13% greater than the volume of a woman’s brain, on average. Some of the most noticeable differences were in areas of the brain that control language, memory, emotion and behavior, according to a 2014 report in the journal Neuroscience and Biobehavioral Reviews.
To find out whether these structural differences translated into cognitive differences, scientists examined detailed brain scans of more than 1,400 men and women. No matter which group of people they looked at, what type of scan was used or which part of the brain was examined, the researchers consistently failed to find patterns that set men and women apart.
“Although there are sex/gender differences in brain structure, brains do not fall into two classes, one typical of males and the other typical of females,” the team wrote in a study published Monday in the Proceedings of the National Academy of Sciences. “Each brain is a unique mosaic of features, some of which may be more common in females compared with males, others may be more common in males compared with females, and still others may be common in both females and males.”
To figure this out, the team — led by psychobiologist Daphna Joel of Tel Aviv University in Israel — went hunting for examples of brain “elements” that were either clearly male or clearly female. In other words, they looked for examples of measurements that appeared to cluster one way for men and another way for women, without much overlap in the middle. Then, after identifying these elements, the researchers looked to see whether women tended to have the “female” versions and men tended to have the “male” versions.
They started with a set of MRIs that measured the volume of gray matter in the brains of 112 men and 169 women ages 18 to 79. On these scans, they examined 116 separate regions and zeroed in on the 10 that showed the greatest difference between men and women. In each case, the 281 scans were divided into three categories — one-third considered “most male,” one-third considered “most female” and one-third in the middle.
