By Stephanie Leguichard

False biological claims have been used to justify prejudice and discrimination against women and BIPOC (Black, indigenous, and people of color) for centuries, if not millennia. To describe the innate differences between men and women, Aristotle once said in the 4th century BCE that “the female is as it were a deformed male.” And more recently, Freud wrote in his 1925 paper titled “The Psychical Consequences of the Anatomic Distinction Between the Sexes” that “women oppose change, receive passively, and add nothing of their own.”

Today, a modern version of biological sexism has emerged: neurosexism. Coined by Cordelia Fine in 2010, “neurosexism” refers to the idea that differences between men’s and women’s behaviors and abilities are rooted in biology–as opposed to other factors–and that men are born with superior brains that give them superior abilities. Neurosexism is fostered and perpetuated by scientific studies that claim to prove these regressive ideas about gender differences, and the results of these studies are frequently used to justify and perpetuate negative gender stereotypes and to discourage women from pursuing certain professions and other roles.

Here are six reasons why neurosexist claims are extremely harmful, problematic, and false:

1. Neurosexism is often used to defend the status quo of gender-based income inequality. 

One of the most pervasive neurosexist assumptions is that men’s brains “naturally” make men more rational, logical, and highly skilled in math and science, while women’s brains make them more caring, emotional, and skilled in language and the arts. Prominent cognitive psychologist Simon Baron-Cohen has even directly asserted that “the female brain is predominantly hard-wired for empathy. The male brain is predominantly hard-wired for understanding and building systems.” He claims that these differences in “hard-wiring” make women more fit for nurturing roles as caretakers, nurses, social workers, and therapists and men more equipped for more lucrative professions as lawyers, scientists, engineers, and bankers. 

2. Beliefs that the brains of women and men are fundamentally different fuels bigotry against trans, intersex, and non-binary folks. 

The idea that people’s brains innately differ based on sex is often used to justify the idea of a “natural” gender binary. Anti-trans conservatives and TERFs (trans-exclusionary radical feminists) often try to delegitimize trans women’s status as women by claiming that it’s impossible for someone born with a “male brain” to become a woman. Because of their belief in a rigid gender binary (73% of Republicans believe that gender is strictly binary), they commonly express that even if a trans woman fits feminine gender norms, she can never change her “male brain” and can therefore never change her “male” way of thinking and behaving. Given these degrading assumptions, it’s not surprising that 48% of Republicans say that they would be uncomfortable having a friend who is transgender.

3. Studies that demonstrate brain differences can’t actually distinguish between differences that are innate and differences that are created by culture and other factors. 

In other words, they don’t identify whether the differences are due to nature or nurture. The only way to prove that dramatic brain differences are “natural” or innate would be to prove that they’re present at birth or at least among children. But no studies have successfully proven this. As neuroscientist Lise Eliot has written, “what I found, after an exhaustive search, was surprisingly little solid evidence of sex differences in children’s brains.” It’s therefore no coincidence that most studies that have supposedly found brain differences have involved only adults. These studies have presumed that since these differences are manifested in these individuals’ brains, they must be innate.

This assumption is completely unfounded: a vast amount of research has proven that the brain has an amazing degree of “plasticity,” meaning that it can drastically change on a neurobiological level through repeated behaviors and social conditioning. This is why the motor cortex (a part of the brain involved in planning movement) tends to become larger over time among professional jugglers, and the hippocampus (a part of the brain involved in spatial navigation) expands among taxi drivers. Similarly, since women are relentlessly encouraged from a young age to spend their time caring for others and to focus on using their social, emotional, and language or communication skills, their brains may begin to function somewhat differently than men’s over time. But any differences that emerge are only created by lived experience and conditioning, not by biology.

4. Research that fails to prove gender stereotypes is often discarded, and research that confirms gender stereotypes gets the most attention.

When researchers design and execute studies, they’re often seeking specific results that prove their expectations and bolster their agenda. They also prefer to publish their results if they’re dramatic and eye-catching. Cordelina Fine refers to this as the “file-drawer” phenomenon, whereby studies that do find sex differences get published, but those that don’t languish unpublished and unseen in a researcher’s file drawer.” And not surprisingly, it’s often the studies that make the most extreme claims that are remembered and circulated the most because of their “sexy” nature. 

For instance, one famous 1982 study found that women tend to have a larger corpus callosum, which is the part of the brain that bridges the brain’s two hemispheres. It was assumed that a larger corpus callosum would help the two sides of a person’s brain communicate with each other and that this would give the person better collaborative, social, and “multi-tasking” skills. Based on that study, it became popular among researchers and news outlets to assert that this confirms stereotypes that women are more emotional and intuitive and more capable of multi-tasking (and therefore of balancing housework and childcare with employment).

However, and conveniently for neurosexists, the aspect of the study that’s been forgotten is that it only involved nine men and five women. Any good researcher knows that this sample size is way too small for the study to mean anything. And a more recent review of 50 relevant studies found that it’s actually completely untrue that women’s corpus callosums are larger. Yet, many prominent neuroscientists continue to cite this myth as evidence that women think completely differently. 

5. Researchers often unintentionally (or perhaps sometimes intentionally) introduce bias into their studies through poor design.

For example, one recent study attempted to prove the sexist idea that girls are naturally more people-oriented and empathetic and that boys are more interested in moving objects and systems. It did so by measuring whether newborn babies preferred to look at a mobile being moved above them or the face of the researcher next to them. The study compared how long the babies looked at the mobile versus the face, and it found that the girls tended to look slightly longer at the face and that the boys spent slightly longer looking at the mobile. 

Not surprisingly, the media quickly claimed that this study proves that women are born more emotional and social rather than rational. But the study’s design had a major flaw that most likely heavily skewed the results: the researcher was informed of the sex of some of the babies, and this caused the researcher to (perhaps subconsciously) act more encouraging (through smiling, a more excited tone of voice, etc.) when the baby looked at what she expected based on the baby’s assigned sex. Since babies are sensitive to such social cues, the slight sex difference discovered can most likely be attributed to this. And that would explain why sex differences haven’t been found in any similar studies that have actually accounted for this.

6. Neurosexist beliefs can create a self-fulfilling prophecy. 

Alarmingly, merely being exposed to neurosexist ideas has been shown to influence women’s performance and behavior in ways that perpetuate supposed gender differences. For example, when women are told that men are naturally more talented than women in a certain area, they’re more likely to perform poorly on related tasks. In one study, women performed worse on a math test after reading an article that argued that men’s innate biological abilities make them better at math. Conversely, the group of women who were assigned to read an article stating that men are only better at math because they try harder performed significantly better.

Now that neurosexist ideas have been exposed for what they are, it’s time to eliminate them from our culture and stop using them to justify toxic and restricting gender norms. Next time you hear someone talking about how “men are from Mars and women are from Venus,” take what they say with a grain of salt. Or when you hear about a new “groundbreaking” study about sex differences on the news, remember how neurosexism can be cleverly disguised as the truth.