Forget all those glowing brain scans, here’s the real science behind the differences between men and women.
If I see someone crying, I cry–without fail. It isn’t purposeful, it’s just how my brain reacts. My husband, by his own admission, is like the Tin Man, just without the quest for greater emotional expression.
This difference between us, which can lead to frustration from me and eye rolls from him, is a common refrain among men and women. It is just one in a long litany of supposed differences between (straight) men and women. Also included, women are nurturing, talkative, and spatially inept, whereas men are assertive, logical, and mechanical, and on and on.
Hundreds of years ago, people blamed these differences on women’s reproductive organs (somehow blood in a uterus was supposed to make it difficult to reason). Now with advances in neuroscience, the answers seem more sophisticated: Men and women are different because we have different brains. This is propagated by clickbait articles and news segments that show the brightly lit images of brain scans explaining away our frustrating gender differences with “scientific evidence.” Pink brains and blue brains are easy to sell in a world where we have been told for generations that men are from Mars and women are from Venus.
MOST BRAINS ARE BOTH “MALE” AND “FEMALE”
The problem with blaming differences between women and men on pink brains and blue brains is that it isn’t really true. But the idea sticks around because there are just enough kernels of truth to obfuscate the real picture.
Indeed, there are some differences in the brains of men and women. Men’s brains are about 10% bigger than women’s brains, which happens to be about the same as our height and weight difference. But women compensate for that smaller size by having more wrinkled brains that also have more gray matter relative to white matter than men, basically allowing more important stuff to get packed into a smaller area.
And indeed, there are some important sex differences in mental health, neuropsychiatric disorders, and learning disorders that are clearly neurobiological.
But most of the differences that stubbornly float around popular culture have been clearly refuted in the scientific literature. A classic example is the idea that the female brain has a larger corpus callosum (the section of the brain that connects the two hemispheres) and less lateralized brains than males. The corpus callosum notion has been a popular idea since a study was published in 1982 that got picked up by Time and Newsweek.
These statements have been extrapolated and translated into the popular belief that women multitask better (and why women are supposedly better at simultaneously calling the doctor’s office, cleaning the kitchen, and helping with homework). The problem is that these statements have been heavily refuted by multiple independent meta-analyses (which are just large meta-studies that analyze all available studies together), with one of the meta-analytic researchers calling it a “myth.” These studies are more scientifically valid and reliable, but not nearly as sexy, so they don’t get covered.
The most convincing scientific evidence about gender in the brain is much more complicated than a news soundbite allows, but it makes a lot more sense than the idea that we have different brains.
Neuroscientist Daphna Joel and her team examined the brains of 1,400 individuals (quite different than the typical neuro-imaging study that includes about 10 men and 10 women). They repeatedly find that some individual, small sections of the brain indeed show patterns that are more typical of males or more typical of females (although millions of sections show no difference at all).
However, when they look at all the sections together instead of just a small snapshot, they find only about 3% of people have a brain that is fully “male” or fully “female.” In other words, it is extremely rare to find a consistently pink brain or blue brain. The other 97% of people have brains that are a mosaic of pink and blue. Almost all of us have features common in men and features common in women.
Even neuroscientists can’t tell if an individual brain belongs to a man or woman.
The mosaic idea actually seems to be common sense. We know that we are all individuals made up of unique experiences. Those experiences shape the structures and connections within our highly complex brains.
Even our number of neurons differs widely. The average brain holds about 86 billion neurons, but individuals differ from that number by an average of 8 billion. Even identical twins have different brain structures and connections because of their own experiences. We are all our own idiosyncratic mosaic–in our behaviors, skills, and brains.
WHAT’S REALLY BEHIND GENDER DIFFERENCES
Why does the myth of pink brains and blue brains stick so firmly in our collective consciousness? One reason is because men and women often do have different interests and ways of acting. My husband and I are sincerely different. This is primarily because we come from different cultures, mine (the culture of being raised as a girl) encouraged emotional expression, and his told him that “boys don’t cry.”
Anyone that has traveled knows the importance of cultural influence, yet we don’t chalk up those cultural differences to neuroscience. Rather, as humans, we effectively adapted our behavior to our social norms and pressures.
The other reason the myth is so stubborn is that we like to remember examples that are consistent with our gender narrative. We remember information better when it supports our theory that men and women are different. We overlook all the men who cry, who easily multitask at work, and who can’t do math. It helps us keep a simplified and consistent picture in our brains.
Research by behavioral psychologists has shown in studies with 1 million-plus people that our individual differences are much larger than any group-level gender difference, and that no individual fits the male or female stereotype perfectly.
The end result is that our gender is a pretty uninformative part of who we are. It doesn’t determine our brain structure, it doesn’t determine what tasks and jobs we are good at, and it doesn’t determine much about who we are. Humans, and our brains, are much more complicated than that.