After a little hiatus, I’m baaaaaack!! What better way to come back then with a post in my brain health series. Today I’ll be sharing what I’ve learned scientifically speaking of how male and female brains are different. Additionally, I might add some of my commentaries.

This and many of my brain health series are inspired by the research done by Dr. John Medina as presented in his book, Brain Rules.

I believe understanding how our brains work is useful in living a successful life, working a successful recovery program, and managing finances successfully. And that’s why I read and write about the marvelous human brain.

Male & Female Brains are Different

Dr. Medina’s explores the differences between male and female brains in his chapter titled, Brain Rule #11 Male and Female Brains are Different. Medina gives a brief overview from three different angles:

1. Genetic
2. Neuroanatomical
3. Behavioral

Genetic Differences in Male & Female Brains

Okay, so let’s go back to Biology 101 and get refreshed on a few facts…

Chromosomes are strings of DNA and you received 23 from your mom and 23 from your dad. Two of your chromosomes are sex – X or Y. Everyone has an X chromosome but females don’t have a Y one. Therefore, XX is female and XY is a male. One fascinating fact that I forgot about from H.S. Biology is that only the sperm can donate the Y so, the father is the one who determines the sex assignment.

X chromosomes have about 1,500 genes while the Y chromosomes have only about 100. Since males have only one X chromosome, they need every one of those genes. Furthermore, since males receive their X chromosome from their mom, all-males are literally, as Medina puts it, “Momma’s Boys”

Females, on the other hand, have more genes than they need so the female embryo ignores one of the Xs. Researchers have observed that some cells in developing girls use the X from mom and other cells use the X from dad. As far as they can tell it’s quite random as to how they are selected. The cells in a female embryo are complexly made up of a myriad of active and inactive X genes from both parents.

Because many of 1500 genes in the X chromosome were discovered to create proteins involved in brain manufacturing, this is the first indication of genetic differences between male and female brains.

Neuroanatomical Differences in Male & Female Brains

Medina points out that scientists of both sexes 😉 have found that certain areas of the brain are fatter in males or females. For example, the limbic system is much larger in men. The limbic system is where the amygdala resides and is responsible for emotions and the ability to remember them. Isn’t just plum opposite of the typical stereotype about females being more emotional??

Another interesting tidbit is that female’s amygdala, at rest, communicates with the left side of the brain, and the male’s amygdala communicates with the right side of the brain. Medina challenged my belief that the left side of the brain is responsible for logically related tasks and the right creative ones. Apparently that is folklore and both sides of the brain are involved in all tasks.

However, Medina points out that the hemispheres are different. The right side tends to remember the gist of a situation and the left side remembers the details. Hmm…

Medina also enlightened me to the fact that males synthesize serotonin (the chemical responsible for regulated emotion and mood) ~52% faster than females. Stats show that females are more likely to suffer from depression. Another hmm…

Behavior Differences in Male & Female Brains

Emotions

Researcher Larry Cahill viewed men and women’s brains under acute stress. I guess he showed them horror movies and recorded some thought-provoking findings. Firstly, we have two amygdalae.

In men’s brains, their amygdala in their right hemisphere was fired up during the acute stress. Yep, you guessed it, women fired up their amygdala in their left hemisphere. Cahill wanted to find out if women tend to remember the details of emotional experiences while men remember the gist.

So he conducted the experiment again but gave the subjects propranolol which when used as a beta-blocker, inhibits the biochemistry that activates the amygdala during emotional events. In laymen’s terms, it will affect both sex’s ability to recall. Afterward, the females forgot the details of the story and the men forgot the gist. And yet, another hmm…

Medina warns not to take too much from that experiment but he does go onto say that other labs have extended Cahill’s work and have found very similar results.

Verbal Communication

Behaviorist, Deborah Tannen, has studied how male and females communicate verbally. Women use both brain hemispheres during communication and men typically use one. Furthermore, women have thick cables connecting their brain’s two hemispheres and men have thinner ones.

It’s thought that perhaps these differences in the female and male brain are why language and reading disorders occur twice as much in boys. Additionally, women recover faster from the verbal effects of strokes.

Relational Behavior

Tannen spent years observing and recording the interactions of both young boys and girls with their friends. Girl best friends lean in, maintain eye contact, and talk!! On the contrary, boy best friends rarely face one another or make eye contact. Boys are bonded by doing physical things together.

However, by middle school boys begin using verbal skills to negotiate their status in large groups. You know alpha male kind of stuff!

Tannen found that girls also have a hierarchy. For example, your best friend is someone you tell your secrets to.

I simply love the story that Tannen gives as to how this difference in communication continues into adulthood. A wife and her husband were driving in the car and the wife asked, “are you thirsty?” The man says no and so they kept driving past the exit. The wife got annoyed because she wanted to stop and the husband got annoyed because she wasn’t direct.

Tannen imagines how this conversation would have occurred between two girlfriends. Most likely the friend would have answered the question with something like, “I don’t know, are you?”

Again I’m finding this all very engrossing.

Closing Thoughts

It was evident to me before I read this chapter by Medina, that male and female brains are different. How can I tell? Well, from my 47 years of experience in communicating with both sexes, I’ve found it’s just different. However, I’m delighted the research confirms this.

Moreover, what do we do with this research? I think we recognize it and practice grace with one another…always.

Medina spoke with a group of executives about Cahill’s research of gist versus details. Medina explained that women are often stereotyped as being the more emotional sex; however, women may just have more data points for remembering the details of emotional experiences where men recall the gist. He noticed two women in the group crying. Later one of them explained to him, “it was the first time in my profressional life that I didn’t feel like I had to apologize for who I was.”