Men are from Mars, women are from Venus. While those on Venus lack map navigation skills and detached logic, Martians might envy their counterparts' ability to handle several activities at once. Unlike Venusians, men are not very emotionally driven; instead of linguistic or humanistic disciplines, they prefer science, and it is precisely their cold rationality you want to rely on in tense situations.
Nothing highlights the desire to prove the distinctness of men and women better than this interplanetary metaphor… supported by all sorts of neuroscientific research searching for biological evidence to back up this deep-seated hypothesis. So how is it really with the brains of men and women? Is it possible that there is some truth to the tired gender stereotypes after all?
For long centuries, women were considered inferior to men. Giving birth and raising children, caring for the family, toiling in the household day in and day out—certainly. Attaining an education, earning money, pursuing one's own interests, being able to make free decisions, voting—what audacity to try and defy tradition?!
Despite undeniable progress, this worldview is still very much alive in our society. No wonder—changes so immense in history take a while. After all, it was only a few centuries ago that Charles Darwin came up with the theory of evolution, in which, among other things, he described women as "less evolutionarily developed" compared to men. And that stuck.
It is one thing to rely on the hypotheses of credible thinkers, on "the way it has always been," on one's own theories about how the world works. But how tempting is the possibility to prove once and for all that men's brains truly predetermine them to higher intelligence and other advantages…?
Riding the wave of inventions in imaging techniques, neuroscience arrived stronger than ever. The ability to scan, monitor, and compare the brains of living participants brought previously unimaginable research opportunities. And so, scientists are scanning like there is no tomorrow—some of them in an effort to uncover the truth about the origin of the differences in behavior between women and men at the level of brain structure and activity.
It may not surprise you that plenty of differences were found. Let's start with the most obvious one—the average male brain (1,260 cm3) is about 130 cm3 larger than the average female brain (1,130 cm3). This finding is perhaps not so unexpected given the naturally larger male constitution. However, it must be mentioned that brain size does not correlate in any way with intelligence or other abilities—just as longer legs do not mean higher speed. More significant than overall brain size, one study showed differences in its individual parts—higher IQ in women was associated with a larger volume of gray matter in language-processing areas, while men with a higher IQ had more of it in the frontal and parietal lobes (whose functions include, for example, movement and vision control). Another team of scientists measured cortical thickness in a large number of women and men. The thicker this wrinkled surface layer of the brain (important for language, memory, perception, etc.) is, the better a participant's performance tends to be in tests measuring cognitive performance and intelligence. The results of the study probably would not please Darwin and co.—cortical thickness was, on average, greater in women.
Women also have more gray matter overall compared to men—which plays a role in movement control, sensory perception, emotions, speech, or decision-making. White matter, which men have more of instead, is involved in learning and ensures the smooth functioning of individual brain functions. Some research claims that men and women may well process memories, feel emotions, recognize faces, and make decisions differently.
In presenting evidence of the differences between female and male brains, some studies point to differing rates of psychological illness—Cahill, for example, mentions in his publication that women are far more frequently diagnosed with depression, anxiety, and post-traumatic stress disorders, while men more often have problems with addictions. Compared to the opposite sex, male brains have less blood flow, which may help explain why certain types of psychiatric medications work better for women. It is also true that male and female brains differ in their neurochemical composition. Neurotransmitters such as dopamine, serotonin, or GABA are present in higher amounts in women, and these "sex differences in brain structure, function, and neurochemistry likely affect normal and abnormal behavior, and may increase vulnerability to certain types of neuropsychiatric diseases," write Cosgrove, Mazure, & Staley. In light of these facts, however, we must not forget that the influence of the environment (upbringing, relationships, socioeconomic factors) is extremely substantial in the development of psychological illnesses.
Various studies have published findings that fit the simplified picture presented by the media—men handle tasks requiring visual imagination better, while women process emotions better and more intensely. "While popular culture is full of alleged examples of intersex differences in intellect and behavior, only a few, such as higher physical aggressiveness in men, have been proven by professional research," writes Michael Price in an article for Science, adding that when you place a brain scan in front of scientists, they will find it difficult to identify whether it is a scan of a woman or a man.
But… what about all that research that actually did find differences? Surely we cannot ignore so much scientific evidence of intersex distinctness?
Authoritative British neuroscientist Gina Rippon says we can—and indeed we should. She does not deny the physiological differences between men and women, nor the differences in their psychology and behavior; however, she rejects the erroneous attempt to explain them on the basis of innate biological differences. In an interview with Undark, she says that this neuroscientific "hunt for differences" began two hundred years ago when researchers said something like: "We know that women are inferior in our society, with no access to education… so let's use our new research capabilities to show everyone that they are that way because they have different brains." And this approach unfortunately survives to this day. Moreover, a large number of studies on this topic reached their results using problematic methodology or poor data interpretation.
Rippon speaks of the potent influence of upbringing and social customs, and emphasizes the fascinating phenomenon of neuroplasticity—this is a relatively recent finding that "short- and long-term experiences change brain structure." Prejudices, expectations, social norms, and stereotypes demonstrably affect how we process information, how we behave and feel, which skills we choose or have the opportunity to improve… and thereby literally change the structure of our brains. So when, for example, research has shown that men perform better in tasks focused on spatial thinking, one must take into account the fact that as children, they had more space to "train" these abilities compared to women ("typically boy" activities like building blocks, action video games, toy cars, or throwing darts help develop this type of thinking).
It turns out (for example, in this study of more than 1,400 brains) that we do not have sufficient support for the hypothesis of the existence of a typical male and female brain. Each of us, it seems, has a unique "mosaic" of different characteristics in our heads that do not depend on sex, and searching for intersex differences is therefore perhaps a bit of a waste of time.
Sources:
