Why Are Men and Women So Different?
I spent decades sitting at the table with male executives, watching and wondering. What the heck were they thinking, why do they do what they do in the way they do it? I wasn’t judging, I’d been raised by men in my professional life. I respected men. Most of my good friends were men. I was simply trying to decipher what made them tick.
I am sure many of them were doing the same for me. The only woman in their midst.
I spent a lot of time studying the human mind as well. The more classes I took and the more I learned, the more fascinated I became.
I learned some fascinating facts about the difference between men and women’s brains. Facts that opened my eyes to the answer I’d been seeking for so long about what makes men and women tick.
Male and Female Brains Are Just Plain Different
I’m going to share some cool things I learned about our brains. If you'd like to dive in more deeply, there are sources at the end of the blog.
The female brain design is nature’s default design. Every human brain starts to develop as a female.
Around two months in utero, a testosterone surge happens in mom’s body, or it doesn’t.
If the surge happens, the brain changes its development path to become male.
In the male, the surge of testosterone reduces communication and hearing cortices, and shrinks emotional processing and intuition centers. It also doubles the sexual and aggression centers.
A male brain is designed to be highly compartmentalized for optimal “in the box” processing. After all, you don’t want a warrior thinking about his wife and kids back home in the middle of a battle, right?
A female brain continues to build denser communication wiring, larger interconnected memory, and intuition centers that his brain doesn't have. A woman’s mirror neurons give her the ability to literally feel what another person feels.
The female brain is designed to be fully interconnected, giving us our uncanny intuition that the world has tried to label as “woowoo.” It’s anything but. It’s our natural brain power.
Viva La Difference
The impacts of our compartmentalization vs interconnectedness, combined with the different focuses of our brain centers, create two very different processing architectures.
Translation: We ingest very different information around us and we process that information with a very different focus.
Which is why men think women are emotional as women are processing a vastly larger and more diverse data center than a man. Women think men don’t care, as men are processing a very narrow, highly focused segment of data vs hers.
In our professional world the differences create poor communication, misunderstandings, diverse priorities and just plain disorder.
A Simple Example
Let’s take a simple example of sharing information.
Men see information as currency in their transactional world. When they share information with another guy, they create debt. Every piece of information they withhold creates advantage. Which is why I used to watch guys not tell other guys what they had told me privately. I thought it was because it was private information. I was close. It was valuable currency to be shared for optimal returns.
Women on the other hand use information to create connections, be a team player and help others. Let's say that a woman hears a reorg is coming. It will eliminate some of her peer’s team members. Our first instinct is to tell him. After all, we want to be good colleagues and friends. Two months later the reorg happens. He lands on his feet. He's used her information transactionally to reposition himself in a new role with a new team. He is given some or her team to build his own. She sees betrayal, he sees a logical transaction.
The Bottom Line
I appreciate men more now than I ever did. I finally understand what happens in their minds that is so different from what's happening in my own. No wonder they think we are emotional and chaotic.
As I work on my guidebook for women in the rise of the manosphere, I think it’s more important than ever that we understand our differences. The value of our diversity makes us a powerful combination, designed to work in unison.
What a great opportunity in our contentious culture to actually leverage the valuable differences in the way our minds function. Instead of dissing them.
Sources of Information
1. Every brain starts female / testosterone surge at 8 weeks
Confirmed by UCSF (Brizendine's own institution): "Every brain begins as a female brain and it only becomes a male brain eight weeks after conception, when excess testosterone shrinks the communication center, reduces the hearing cortex and makes the part of the brain that processes sex twice as large."
Citation: Brizendine, L. (2006). The Female Brain. New York: Broadway Books.
Also: Brizendine, L. (2010). The Male Brain. New York: Broadway Books. (Elaborates on testosterone marination.)
2. Women have greater connectivity BETWEEN hemispheres / men have greater connectivity WITHIN each hemisphere
This is the landmark Penn Medicine study. 949 subjects aged 8-22. Used diffusion tensor imaging (DTI) to map the structural connectome.
Key finding: Female brains showed greater between-hemispheric connectivity (left-right wiring). Male brains showed greater within-hemispheric connectivity (front-back wiring). The researchers concluded female brains are designed to facilitate communication between analytical and intuitive processing modes.
Citation: Ingalhalikar, M., Smith, A., Parker, D., Satterthwaite, T.D., Elliott, M.A., Ruparel, K., Hakonarson, H., Gur, R.E., Gur, R.C., & Verma, R. (2013). "Sex differences in the structural connectome of the human brain." Proceedings of the National Academy of Sciences, 111(2), 823-828.
DOI: 10.1073/pnas.1316909110
3. Mirror neurons — women have larger gray matter volume in mirror neuron regions
Two key studies here:
Study 1: Women had significantly larger gray matter volume in mirror neuron regions (pars opercularis and inferior parietal lobule). Higher empathy scores were tightly coupled with larger gray matter in these areas.
Citation: Cheng, Y., Chou, K.H., Decety, J., Chen, I.Y., Hung, D., Tzeng, O.J., & Lin, C.P. (2009). "Sex differences in the neuroanatomy of human mirror-neuron system: A voxel-based morphometric investigation." Neuroscience, 158(2), 713-720.
Study 2: Women recruit mirror neuron areas to a higher degree than men during empathic face-to-face interactions, for both self-related and other-related emotional processing.
Citation: Schulte-Rüther, M., Markowitsch, H.J., Shah, N.J., Fink, G.R., & Piefke, M. (2008). "Gender differences in brain networks supporting empathy." NeuroImage, 42(1), 393-403.
4. Women's interconnected processing / intuition / below-awareness integration
This is the newer research that supports the book's scientific foundation. Isenman and Sinclair argue that women do more of their higher-level thinking below awareness because their comprehensive, relational way of processing fits with intuitive cognition. Women's higher density of connections between hemispheres allows more efficient integration of emotional, body-based, and cognitive cues simultaneously.
They also found women delay cognitive closure and detect change earlier than men.
Citation: Isenman, L. & Sinclair, M. (2025). "Women, intuition, and management — the Yin and Yang of nonconscious thought." Frontiers in Psychology, 16.
DOI: 10.3389/fpsyg.2025.1572888
5. Corpus callosum — sex differences visible in utero
Fetal sex differences in the corpus callosum (the bridge between hemispheres) were found as early as 26 weeks gestational age, with females showing significantly larger splenial width.
Citation: de Lacoste, M.C., Holloway, R.L., & Woodward, D.J. (1986). "Sex differences in the fetal human corpus callosum." Human Neurobiology, 5(2), 93-96.
6. The testosterone surge — fetal impact on brain structure
For the specific claim that fetal testosterone organizes sexually dimorphic brain development (including effects on corpus callosum and hemispheric connectivity):
Citation: Chura, L.R., Lombardo, M.V., Ashwin, E., Auyeung, B., Chakrabarti, B., Bullmore, E.T., & Baron-Cohen, S. (2010). "Organizational effects of fetal testosterone on human corpus callosum size and asymmetry." Psychoneuroendocrinology, 35(1), 122-132.
Also: Kim, S. & Kim, M.J. (2012). "The effects of prenatal sex steroid hormones on sexual differentiation of the brain." PMC/NIH.