The Evidence-Based Research Behind
Differences Between Male and Female Brains
The Gist: Yes, on average across populations, there are minor differences in the anatomical structure of female and male brains. Both sexes’ brains brains are far more similar than they are different. Women tend to have thicker cerebral cortices than men, and a thicker cortex is the only anatomical feature shown to significantly correlate with intelligence.
“In 2750 women and 2466 men aged 44–77, Ritchie and his colleagues examined the [MRI] volumes of 68 regions within the brain, as well as the thickness of the cerebral cortex.
“Adjusting for age, on average, [researchers] found that women tended to have significantly thicker cortices than men. Thicker cortices have been associated with higher scores on a variety of cognitive and general intelligence tests. Meanwhile, men had higher brain volumes than women in every subcortical region they looked at, including the hippocampus (which plays broad roles in memory and spatial awareness), the amygdala (emotions, memory, and [fear]), striatum ([motor planning]), and thalamus (processing and relaying sensory information to other parts of the brain).
“Researchers also found considerable overlap between men and women in brain volume and cortical thickness, just as you might find in height. In other words, just by looking at the brain scan, or height, of someone plucked at random from the study, researchers would be hard pressed to say whether it came from a man or woman. That suggests both sexes’ brains are far more similar than they are different.
“The controversial—and still unsettled—question is whether these patterns mean anything to intelligence or behavior. Though popular culture is replete with supposed examples of intellectual and behavioral differences between the sexes, only a few, like higher physical aggression in men, have been borne out by scientific research.”
Interestingly, only the volumes of subcortical structures do not significantly correlate with intelligence.