A Short Journey Into Male and Female Brains

Exploring gender differences in brain architecture.

Posted January 12, 2024 | Reviewed by Tyler Woods

KEY POINTS

From an early age, brain differences lead girls to become more outgoing and more observant than boys.

Studying adult brains helps to explain some notable differences in the way women and men approach the world.

Females exhibit extensive interhemispheric wiring while in males intrahemispheric wiring is more abundant.

​We live in a small Ontario town where every Saturday, an outdoor and indoor farmers’ market takes place. I like to go early to buy flowers. The night before, I ask my wife if there's anything special she wishes me to buy. She may say “eggs” or “see if they have wild blueberries.” At the market, I go directly to my favourite flower stand and buy flowers. Walking over to the egg stand, I ask for “A dozen large browns." I pay and look around for wild berries, in late summer only, but find none. I drive home. The whole trip, on a nice day, takes me about 25 to 30 minutes.

When my wife goes to the market, she can easily spend two or more hours there. I used to ask her (I have learned my lesson; I no longer ask): ”What has taken you so long?” “Well,” she will say, “I talk to the farmers, ask where they come from and what else they are growing. I look for special vegetables like zucchini flowers or baby squash. I may ask for cooking instructions for these and expand my meal options. I like to linger and take in the colours and smells. Sometimes, I meet friends and we chat, or we may sit down and have a coffee.”

Two very different experiences, but, I think, rather stereotypical of the differences between how men and women think and act. These differences are due to many factors, primarily genetic, biological, upbringing, social, and cultural. At present, about 100 gender differences in the brain architecture of women and men have been identified. Because of space limitations, I shall focus here on five of these major differences.

In humans, starting in the first trimester, neuro-hormonally driven brain development in males is slower compared to females, which accounts for the longer period of the development of social responsiveness and regulation of feelings in boys. In other words, boy babies’ brains lag behind in development compared to their sisters. This is reflected in boys' early relationships with their mothers and caregivers.

At 12 months, female toddlers display a greater preference for interactions with caregivers, make more eye contact (7), and show more emotional empathy and interest in people than do same-age boys.

Edward Tronick, examining newborns and infants up to two months old, together with pediatrician T. Berry Brazelton in Boston, concluded that "boys... are more demanding social partners, have a more difficult time regulating their affective states (emotions), and may need more of their mother's support to help them regulate affect. This increased demandingness would influence the infant boy's interactive partner.”

Bonding and attachment will take a little longer and be a little more difficult for boys than girls. If a mother's first child was a girl, she would wonder why her second child, this time a boy, was so much more “difficult.” This label, whether communicated by words or actions, may leave a permanent imprint on the boy’s unconscious mind, with consequent emotional problems.

You can see from the above how brain differences, from an early age, lead girls to become more outgoing and observant than boys. Adults, particularly mothers, grandmothers, aunts, etc., will respond in kind, reinforcing the prosocial behaviour of girls, while fathers and other male relatives will get more rambunctious and more physical with their male children, fostering in them action overthought and feeling.

Studying adult brains helps to explain some notable differences in the way women and men approach the world. Trailblazing research from the University of Pennsylvania found that women typically have a larger corpus callosum than men (6). The corpus callosum forms a bridge of communication between the left and right hemispheres of the brain. As a result, female brains exhibit extensive wiring between the left and right hemispheres. Greater interhemispheric connectivity in females facilitates the integration of the analytical and sequential reasoning modes of the left hemisphere with the spatial, intuitive processing of information of the right hemisphere. This type of structure may facilitate social communication and intuition. In contrast, male brains with a smaller corpus callosum evince greater neural connectivity along the posterior-anterior dimension, which involves the linking of perception to action.

It has been known for a long time that women, on average, have better verbal memory and social cognition, whereas men have better motor and spatial skills. Brain scans have offered an explanation: females tend to have verbal centres on both sides of the brain, while males often have verbal centres in only the left hemisphere. This is probably also the reason why women use more words when describing experiences or feelings and have more interest in talking about these things.

Analyzing data from 168 studies and 355,173 participants, Marco Hirnstein, of the University of Bergen, found a small but robust female advantage in verbal fluency and verbal-episodic memory. The advantage is small but consistent across the last 50 years and across an individual’s lifespan. Moreover, they determined that the female advantage depends on the sex or gender of the leading scientist: female scientists report a larger female advantage, while male scientists report a smaller female advantage.

As we review these studies, we need to keep in mind that they are statistical generalizations and do not apply to individual men and women. Every person is somewhere on a continuum between the typical male and female brains. And, regardless of gender, each person's unique experiences and environment play a vital role in shaping their cognitive abilities and behaviours. It is important to remember that all differences have advantages and disadvantages.

I think Ruben Gur, University of Pennsylvania, said it best: "It's quite striking how complementary the brains of women and men really are."

References

Jantz, G. L. (2014). Brain Differences Between Genders. Do you ever wonder why men and women think so differently? Psychology Today.

Schore, A. N. (2017). All our sons: The developmental neurobiology and neuroendocrinology of boys at risk. Infant Mental Health Journal, 38(1), 15-52.

Ingalhalikar, M., Smith, A., Gur, Ruben & Verma, R. (2014). Sex differences in the structural connectome of the human brain. Proceedings of the National Academy of Sciences, 111(2), 823-828.

Prendergast, D. M., Ardekani, B., Derosse, P., et al. (2015). Age and sex effects on corpus callosum morphology across the lifespan. Human Brain Mapp. 36, 2691–2702. doi: 10.1002/hbm.22800

Xin, J., Zhang, Y., Tang, Y., & Yang, Y. (2019). Brain differences between men and women: Evidence from deep learning. Frontiers in neuroscience, 13, 185.

Hirnstein, M., Stuebs, J., Moè, A., & Hausmann, M. (2023). Sex/gender differences in verbal fluency and verbal-episodic memory: a meta-analysis. Perspectives on Psychological Science, 18(1), 67-90.

About the Author

Thomas R. Verny, M.D., the author of eight books, including The Embodied Mind, has taught at Harvard University, University of Toronto, York University, and St. Mary’s University of Minnesota. His podcast, Pushing Boundaries, may be viewed on Youtube or listened to on Spotify and many other platforms.

Online: Thomas R. Verny, M.D., Facebook, Instagram, LinkedIn