A man's brain is 10%-15% larger than a woman's: Understanding how it matters (at all)

A man's brain is 10%-15% larger than a woman's: Understanding how it matters (at all)

etimes.in | Jan 15, 2025, 04.00 PM IST

Differences between a man and a woman have always been discussed and majorly misunderstood. Among the myriad differences that exist between men and women, brain size often sparks both curiosity and controversy. It’s a fact supported by research: on average, a man’s brain is 10% to 15% larger than a woman’s. But before rushing to conclusions, it’s crucial to ask a fundamental question—does the size of the brain matter, and if so, how?

The implications of this biological difference has always been debated and used against women in several instances. For centuries, the larger male brain was used, often misguidedly, to justify societal beliefs about intellectual superiority.

A study published in the journal Brain compared the brains of 42 men and 58 women postmortem, and found that the brains of men weighed an average of 1,378g, compared with 1,248g for women. A male brain has a higher proportion of white matter and females have a higher proportion of grey matter. Also studies have found that the cortex is thicker in women's brains. The hippocampus, which is involved in memory formation, is larger in men along with the amygdala.

Man's brain is dense in white matter

White matter part of the brain are like the highways; they allow for the rapid exchange of information needed for tasks such as learning, memory, decision-making, and sensory perception. For instance, the corpus callosum, a major white matter structure, connects the left and right hemispheres, enabling them to work in harmony.

White matter contributes to motor function, enabling the brain to send precise signals to muscles for movement. It is also essential for cognitive flexibility and complex problem-solving, as it supports the integration of information from different neural circuits.

White matter plays a crucial role in the brain, acting as the communication network that enables efficient information transfer between different regions. It consists primarily of myelinated axons—long, thread-like projections of nerve cells (neurons) coated in myelin, a fatty substance that insulates and speeds up electrical signals. These axonal pathways connect various parts of the brain and spinal cord, ensuring smooth coordination and functionality.

Woman's brain has a higher proportion of gray matter

Gray matter acts as the brain’s operational hub, handling critical processes that define human thought, emotion, and interaction. Its proper functioning is essential for maintaining cognitive and motor abilities throughout life.

The amount and health of gray matter can influence brain function significantly. Factors like aging, neurodegenerative diseases (e.g., Alzheimer’s), or injury can lead to gray matter loss, impacting memory, cognition, and motor skills. Activities like learning, exercise, and mental stimulation can promote gray matter growth and connectivity.

Gray matter is concentrated in areas like the cerebral cortex, where much of the brain’s cognitive activity occurs. Here, it processes information from sensory organs—like interpreting visual signals from the eyes or auditory input from the ears—and coordinates voluntary muscle movements. It also plays a key role in complex thinking, problem-solving, and decision-making, enabling humans to navigate the world with intelligence and adaptability.

“The men tend to have more grey matter, which is information processing in the areas regulating one's physical movement. The women, on the other hand, tend to have more white matter, which expresses communication between the brain areas and, therefore, better multitasking and emotional processing. This is why, at times, men and women perform specific tasks differently, but are still equal in all ways of learning, solving problems, and thinking deeply,” says Dr. Vipul Gupta, Group Director & HOD - Neurointerventional, Paras Hospital Gurugram.

"This variation in size has nothing to do with the overall intelligence"

"It is true that, on average, the male brain is usually larger than the female brain by approximately 10% to 15%. This variation in size has nothing to do with the overall intelligence, cognitive ability, and functioning of the brain," says Dr. Vipul Gupta.

"On the other hand, studies have found that both genders have similar functions in the brain, even if their sizes differ. The functioning of the brain is not dependent on size, but rather how efficiently it operates and how areas of the brain are connected," he explains.

"Many studies have shown that a man's brain is, on average, 10% larger than a woman's. However, this variation in size cannot determine the differences in intelligence. The intelligence of an individual can't be determined by the size alone but with a bundle of other parameters, such as the connectivity in the brain, how the information is processed, and the like. The variation in size cannot produce any effect on intellectual abilities or cognitive abilities significantly," Dr. Sameer Arora, Senior Consultant - Neurology, Marengo Asia Hospitals Gurugram.

Does this affect how the brain functions in men and women?

"One of the differences between men and women comes in the matter of how people process information, most women normally have verbal centres located on the left and the right sides, hence making theirs an integrated procedure of language expression. Most of the men always have their verbal centers almost solely located at the left hemisphere, with this being assumed to be among the reasons they always seem so great at everything related to reasoning and structured sentences. This difference in the organization of the brain may add to gender-specific strengths in some cognitive tasks like communication and analytical reasoning," explains Dr. Sameer Arora, Senior Consultant - Neurology, Marengo Asia Hospitals Gurugram.

"Also, the connections between different parts of the brain differ between the two genders. The brains of women are typically better at connecting the sides; therefore, they perform better on tasks that include emotional intelligence, situation analysis, conclusion drawing, and intuitive thinking. Men are usually better connected front to back in the brain, which has a lot more to do with motor skills & perception. The variation in brain structure and connectivity will determine the differing ways in which men and women go about solving problems and processing information," he adds.

As science continues to uncover the mysteries of the human brain, it’s clear that the story is more fascinating—than mere size. Whether 10% larger or smaller, the real question isn’t about size—it’s about how we use our brains to bridge gaps and unlock our full potential.