MEN are good at map-reading; women can’t park cars. Men are better at fixing stuff – but only one thing at a time. Women, in contrast, can multitask, and do empathy and intuition better, too. Just don’t ask them to think logically in a crisis.
So say the stereotypes, anyway. It is a widespread idea that men and women are distinguished not only by their genitals and related sexual characteristics, but also by their brains. Take the notorious Google internal memo from 2017, in which now ex-employee James Damore asserted that there were more men in the company’s workforce because women’s high level of empathy and lower interest in coding made them less suited to Google-type work.
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According to this way of thinking, the biological blueprint that determines fixed and inevitable differences in our reproductive apparatus also determines similarly fixed and inevitable differences in the structure of our brains and how they work. If you want to know what underpins differences between women and men in ability, behaviour, temperament and even lifestyle choices, you will .
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The slow recognition that gender identity and even biological sexual characteristics don’t fit into a neat, binary division already calls such assumptions into question. Recently, too, we have begun to understand just how plastic our brains are, capable of being moulded in all sorts of different ways throughout our lives. So where does that leave the idea of predetermined, hardwired differences in the brains of women and men – and with it the rationale for the expectations, roles and achievements of each in society?
The hunt for sex differences in the brain has a long tradition, starting with the absurdities of skull measuring, or phrenology, to explain personality traits in the 19th century. Pretty much ever since, the idea that men and women have different brains has been a given. The aim of research was to pin down the nature of those differences, and to find out how they translate into the go-to list of “well-known” male-female differences: systemising vs empathic, map-reading vs multitasking, logical vs intuitive, and so on.
Early explanations of brain differences often centred on the “missing 5 ounces” phenomenon. Bigger brains were thought to be better brains. As women’s brains are, on average (an important term that we will return to later), around 10 per cent lighter than men’s, amounting to about 5 ounces or 140 grams, they were deemed inferior.
Later explanations tried to pin differences on specific structures in the brain. In the early 1980s, for example, came the idea that the corpus callosum, the bridge of nerve fibres connecting the two halves of the brain, was . This fitted neatly into the pre-existing concept of “right” and “left” brains: that the left half of a human brain is responsible for language as well as analytical and logical types of thinking, whereas the right half handles emotional processing and creativity. So women’s famed multitasking abilities and greater emotional awareness could be framed in terms of their enhanced and near-simultaneous access to both sides of their brain, thanks to their enlarged corpus callosum.
The advent of brain imaging technology at the end of the 20th century, alongside sophisticated computer models of brain function and better systems for data analysis, finally made it possible to generate the evidence necessary to properly test the ways in which the brains of men and women differ. But as well as some thrilling and groundbreaking research, it unleashed something of a tidal wave of neuro-nonsense.
The colour-coded maps of brain activity that researchers could now produce with such apparent ease were wonderfully seductive. Many people didn’t appreciate, however, that these weren’t real-time photographs of the brain in action, but the end product of a long chain of mathematical processing. The colour coding was chosen by the imaging software to make the most of the real but infinitesimal differences between activity averaged – that word again – across groups or tasks. With a large part of the agenda in brain research still being driven by the hunt for differences between men and women, assertions of the “Men Are from Mars, Women Are from Venus” type were one misleading end product.
One study, published in 2014, illustrates the problems associated with this approach. Researchers at the University of Pennsylvania measured brain connectivity pathways in a large group of women and men. They reported This, they claimed, showed that “male brains are structured to facilitate connectivity between perception and coordinated action, whereas female brains are designed to facilitate communication between analytical and intuitive processing modes”.
But the study didn’t measure whether its subjects actually showed these supposedly typical male and female traits. Measurements of brain connectivity were being filtered through preconceived, stereotypical beliefs. What’s more, many of the reported differences were quite small, and there were many more possible pathway comparisons that didn’t show any differences. The study only reported those that did. Yet the results were eagerly reported in the popular press, with headlines such as ““.
There are good reasons to think that such studies are chasing shadows. For a start, correcting the data for brain size can cause the apparent differences in brain structures between women and men to disappear. The claimed difference in the size of the corpus callosum is .
Not born this way
The fact is, bigger people have bigger brains, regardless of their gender. Bigger brains are different from smaller brains, in both their core structures and . But there is no evidence to suggest that bigger brains are better brains. After all, humans are (on average) cognitively superior to species with far larger brains, including the sperm whale and the African elephant, to name just two.
More crucially, the idea of distinct female and male brains depends on the adult endpoint of brain development being a fixed, predetermined destination. żěè¶ĚĘÓƵs used to think that beyond the changes that occur during the highly plastic early years of the brain, and barring deviations caused by damage, disease or deprivation, you generally end up with the brain you were born with, only bigger and better connected.
We now know that isn’t the case. Our brains are very much a product of the lives we have lived, the experiences we have had, and our education, occupations, sports and hobbies. The way we perform tasks reflects not just the running of predetermined internal software, but also external inputs. One famous example was reported in working London taxi drivers who have done The Knowledge, which requires memorising different routes through the 25,000 or so London streets within a 6-mile radius of Charing Cross. Their brains are , retired taxi drivers and even bus drivers, who navigate fixed routes.
Crucially, brain-changing experiences may differ for men and women. Perhaps it was this effect that early researchers, focusing solely on dividing their groups of participants into men and women, were actually tapping into.
Take one of the allegedly most robust brain differences: in spatial thinking, the skill underpinning navigational abilities or map-reading. In 2005, psychologists Melissa Terlecki of Cabrini College and Nora Newcombe of Temple University, both in Pennsylvania, showed that playing computer and video games is a than biological sex is. There were higher levels of such experience among male participants, but women with the same level of experience had equally good spatial skills.
“Playing computer games is a better predictor of spatial skills than biological sex is”
Any regular activity, be it playing Tetris or Super Mario, or learning juggling or origami, . So if one group is more likely to engage in an activity than another, this will determine their ability, rather than any other characteristic.
In addition, stereotypes about any group’s innate abilities can become self-fulfilling prophecies. If someone is made aware of a negative stereotype about the group to which they belong, this can impair their performance in a related task. For example, if a woman is told that women are poor at a particular mathematical skill, there is a . Studies of this so-called stereotype threat have shown that if a task is presented in a positive context, then both the associated brain processes and how well someone performs the task . It isn’t just experiences that can change our brains: attitudes, especially powerful social stereotypes, can too.
And it may be that we need to challenge the assumptions behind the hunt for differences between male and female brains. Its origin is in the assumption that men and women are profoundly different in their abilities, behaviours and preferences. But what if these “well-known” differences aren’t as marked as has been claimed, and have changed over time or in different contexts or cultures? This would certainly challenge the notion that they are inevitable or based on fixed brain characteristics.
Revisiting the evidence suggests that women and men are more similar than they are different. In 2015, a review of more than 20,000 studies into behavioural differences, comprising data from over 12 million people, found that, overall, the differences between men and women on a wide range of characteristics such as impulsivity, cooperativeness and emotionality .
Perhaps the final nail in the coffin of female and male brains as a scientific concept can be found in a 2015 study by Daphna Joel at Tel Aviv University in Israel and her colleagues. They examined the characteristics of more than 100 brain structures in over 1400 brain scans and found that it was impossible to divide these neatly into two sets of “female-typical” or “male-typical” brains. Each brain had a mosaic of different characteristics, some considered “female”, some “male”. Only around one in 20 of the brains even had sets of characteristics that could be described as predominantly one or the other.
“It’s not just experiences that change our brains – social stereotypes can too”
Applying similar analyses to data sets of psychological variables such as engagement in sports, impulsivity or scores on tests of masculinity-femininity revealed the same lack of binary grouping: no individual had all-female or all-male tendencies. More recently, using machine-learning techniques on data from more than 2000 brains showed that none fitted into one of two neat, non-overlapping sets that could be labelled “brains from women” or “brains from men”.
Where does all this leave us? We find ourselves talking about average differences between men and women that, in general, reflect a tiny difference between two closely overlapping sets of data. Not only that, but the variability and range within each supposedly homogenous set is usually far greater than the differences between the sexes. You might start to wonder why we are still talking about these differences at all.
For sure, biological sex must be considered as one of the variables in investigations into brain differences, so we can understand things such as responsiveness to different medications, or susceptibilities to mental health problems such as depression, physical problems such as Alzheimer’s disease or immune disorders. This might also give insights into the true reasons for women’s under-representation in fields of science and technology. But a focus on biological sex as the sole source of such differences is at best incomplete and could be misleading. Thinking of a brain-based condition as belonging solely to women or men may miss the clues offered by, for example, brain size or body weight, or brain-changing life experiences.
In some of my own team’s research on autism, we are starting to realise that holding to the belief that this is a “male” condition means we are missing the many girls and women who clearly fit the diagnosis. Diagnostic tools are masculinised, with examples of children’s unusual interests and obsessions slanted towards those more commonly associated with boys. Not only does this mean that the undiagnosed girls aren’t getting the help they might need, but research is losing a rich source of additional evidence: many brain-imaging studies of autism have only male participants.
This isn’t just a question of importance to individuals, however. Believing that only one type of brain is capable of certain core skills may lead to an immense loss of human capital, to the detriment of wider society. Who knows how many more software engineers global tech firms might find if we accepted that there is little reason to believe that this is a pursuit to which only men are suited.
It is finally time to discard this old chestnut. The concept of the female brain or the male brain is outdated and inaccurate. Every person’s brain is unique. The value comes from knowing where these individual differences come from and what they might mean for the brain’s owners.
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Gina Rippon is a cognitive neuroscientist at the University of Aston in Birmingham, UK, where she uses brain-imaging techniques to study conditions such as autism and dyslexia. She is the author of The Gendered Brain (Bodley Head)
