By Indre Viskontas, PhD, University of California, San Francisco
The idea that men and women think, talk, and understand things differently has existed for decades—inspiring books, college courses, research studies, and countless sitcoms. The truth is much more complicated and nuanced.
If you’re a neuroscientist with a penchant to be profiled in the news, one sure-fire way to get there is to study sex differences in the brain and then make some grand conclusions about how women are more emotional than men.
But if you are a person who is intellectually-curious and interested in understanding what science can tell us about ourselves—while avoiding hype and hyperbole—apply your skepticism and set the bar for evidence very high when you read a popular press article documenting the latest study on sex differences.
This is a transcript from the video series Brain Myths Exploded: Lessons from Neuroscience. Watch it now, on Wondrium.
Differences Between Men and Women: Three Important Regions of the Brain
The similarities between the brains of men and women far outweigh the differences, and the differences are hard to tease apart from different environments. There are three regions in the brain on average that have different volumes in men and women, after correcting for body size, that needs to be discussed: The amygdala, an almond-shaped structure that plays a key role in the emotional modulation of memory; the hippocampus, whose job is to lay down new long-term memories and to navigate through space; and the corpus callosum, the fiber tract that joins the left and right hemispheres.
Learn more about the neurological principles magicians rely on
How Men and Women Remember Emotional Events
Starting with the amygdala, this region of the brain is why we remember details of events that were very emotional, such as where you were when you heard about 9/11.
The amygdala is larger in men than in women, however, in women, the hippocampus is larger than in men. The corpus callosum, on the other hand, depends on how you measure it. Each of these regional differences is far more complicated than it first seems.
We used to think that the amygdala was primarily concerned with negative emotions, especially fear. But with more data, there is now good evidence that the region leaps to action when we are experiencing strong emotions, regardless of their valence. When the amygdala is active, we tend to form stronger and more vivid memories of whatever we are experiencing.
Learn more about why the brain is still very much a work in progress
Flashbulb Memory—Differences in Men and Women
You might have heard the term flashbulb memory, a characterization of a memory that you might have that seems to be particularly vivid—as though a moment in time has been captured by the flash of a camera. The amygdala plays a role in telling the hippocampus, the region that lays down new long-term memories, to pay attention.
Studies have documented the behavioral differences in the recall of emotional events by men and women: Women appear to have stronger, more detailed memories of emotional events and can bring them to mind more quickly, therefore, the theory is that the increase in memory strength that happens with emotion is more prominent in women than in men, on average.
Learn more about the differences in the male and female amygdala and hippocampus
While this memory enhancement sounds like a benefit, it might also be one of the reasons why women tend to be diagnosed more frequently with disorders like depression, anxiety, and PTSD. There’s some evidence to suggest that memory for things that happened right before an emotional event is worse in women than in men.
You might also have heard that men and women differ in terms of how their brains are ‘wired’. Usually, wiring means how the different parts of the brain are connected. You’ve probably heard the idea that the two hemispheres are more tightly connected in women than in men.
...on average, women’s brains have proportionally more gray matter than men’s brains Click To TweetBut on average, women’s brains have proportionally more gray matter than men’s brains while men’s brains have a larger percentage of white matter. Discussed in a previous article, white matter is the stuff that connects neurons. Moreover, when we look at the corpus callosum—which is the largest bundle of white matter in the brain—the connectivity story gets even more complicated.
Brain Differences Between Men and Women: A Bridge Between Hemispheres
The corpus callosum is the fiber tract that joins the left and right hemispheres in the brain and is often cited as one of the regions that show robust sexual dimorphisms: Women tend to have larger and more bulbous corpus callosa than men, and this finding has been interpreted as showing that women have more communication between hemispheres and think more holistically. In 1982, a study published in the eminent journal Science first reported this difference.
Then, in 1991, a second paper came out in the highly reputable Journal of Neuroscience indicating that it’s more bulbous in women, but more tubular in men and the total area is the same.
Following that, a meta-analysis in 1997 found no significant sex differences across 49 studies of the corpus callosum.
Finally, a study in 2003 in India showed that in Indian brains, the corpus callosum is longer in males than in females and that it increases with age in males, but not in females.
Learn more about alternate ways to train your brain
What these studies show is that measuring brain volumes, even in the same region, is complex and that variability with age, culture, and other factors muddies the waters significantly.
Besides, the corpus callosum appears especially prone to neuroplasticity: Musicians, for example, after much training, have been shown to have larger corpus callosa than non-musicians.
Musicians have been shown to have larger corpus callosa than non-musicians. Click To TweetAnd yet, when those first studies came out in 1982, many scientists and journalists were quick to tell a good just-so story: Of course women have greater connectivity between their hemispheres; they think more holistically and intuitively. Of course men’s brains are more modular; they look for solutions to problems and focus on one thing at a time.
Some of these differences in connectivity have also been used to promote the left/right brain myth: The idea that because women supposedly have greater interaction between the hemispheres, meaning they have greater access to the non-dominant, intuitive, and emotional right hemisphere. In contrast, theoretically, men are dominated by their logical, analytical left hemisphere.
No matter whether you are male or female, the brain is a complex organ that we have only begun to fully understand. While there are many obvious differences between the sexes, neuroscientists are only just scratching the surface of how our physiology affects the many nuances of our behavior and characteristics.
Common Questions About Differences in Gender and Emotion
It is generally thought that while women experience and express emotional states more openly than men, this is not linked to biology but rather to socialized gender roles.
Studies have shown that on average the male brain is physically larger. This does not insinuate a correlation with intelligence.
Yes. Culture plays a large part in how emotions are experienced, and in the Western individualist society, the degree to which emotions are expressed is a signifier of personality.
Studies have found that women report feeling emotional states for others more than men, and this experience of emotion suggests a difference in gender expression of empathy.
