Scarcely a week goes by without a study on gender differences in the brain making headlines. “Female brains really ARE different to male minds,” reported the Mail Online on July 28, while a day later Salon framed the same research as “Women are getting smarter faster than men.” The tired old Mars-Venus debates play out simplistically in the media, like a never-ending tug-of-war, while feminists and anti-feminists alike rage, celebrate, or down their blood-pressure medication, depending on whose side has been thrown the bigger scientific-breakthrough bone.
A great deal of this media coverage resorts to gender essentialism, the belief that behaviors typically associated with either males or females are biological or innate. Sometimes scientists themselves are guilty of jumping to this conclusion: For example, a 2007 study at Newcastle University attempting to explain baby girls’ preference for pink found that Western women preferred red-purple shades of blue and Western men preferred more blue-green shades. The researchers speculate that women’s preferences stem from the need in prehistoric societies for gatherers to spot ripe berries; or perhaps from the need, in their roles as “caregivers and empathizers,” to more easily identify changes in skin color caused by emotional or social-sexual signals. The fact that, overall, Western participants preferred blue and Chinese participants preferred red is underplayed, and no mention is made of the recent preference of blue for girls and pink for boys—a cultural norm that was spun on its head only within the last century.
Feminist resistance to poor arguments such as these, and concern over the potential impact they may have on the struggle for equality, is both explicable and understandable. “There is a long history of men pointing to supposed scientific facts to argue that women are less rational, mature, and intelligent than men,” says biologist and trans activist Julia Serano. Everything from violence against women to inequalities in the workplace has been excused by ideas about “natural” tendencies. As a result, feminists have often responded to this problem by emphasizing social constructionism—the idea that all behavioral aspects of gender are the result of cultural practices and socialization. Social constructionists point to gender-specific toys, differential treatment of children by caregivers and teachers, and differences in encouragement and mentorship, among other factors, to explain persistent behavioral differences between men and women.
And yet, feminists taking a strong stance on an unanswered scientific question could be a dangerous move. For now, the scientific jury is still out on the question of what causes behavioral gender differences, but should the weight of evidence come down on the side of gender essentialism—with feminism having rested its arguments on social constructionism—other conclusions of feminism could also be called into question, a disastrous consequence for gender justice.
Instead, taking a more holistic view of gender and sex—one that examines the roles of shared biology and shared culture alongside individual biological variation and individual experiences, all coming together in a complex way to shape our genders and sexualities—could play a vital role in protecting feminism from the capriciousness of scientific research. This more nuanced position, argues Serano, also has the “crucial benefit of fostering inclusiveness rather than exclusivity.”
What Do We Know?
Scientists who research sex and gender work in a huge array of disciplines, including anthropology, biology, social psychology, medicine, psychiatry, evolutionary psychology, genetics, and neuroscience. With any scientific debate, looking for consensus is vital. In some cases, like climate change or evolution, consensus is clear. Not so for sex and gender, where researchers in different disciplines, and often within the same discipline, have widely differing opinions and vastly different techniques for tackling the subject. (A note: This section refers to sex-based differences among cis people due to the populations studied in this research, and so the terms “male” and “female” are used interchangeably with “men” and “women”—an issue addressed later on.)
However, there is one main point on which everyone agrees: the “nature vs. nurture” debate is overly simplistic, with many scientists asserting that both biology and society play a role in every element of human behavior. “Trying to disentangle nature from nurture is meaningless,” says Jamie Lawson, a teaching fellow at England’s Durham University’s Department of Anthropology. “We’ve come to understand that genes respond to the environment. They’re like little biochemical switches that turn on and off, so all animal behavior is understood to be an interaction between nature and nurture.”
Kevin Mitchell, a senior lecturer in genetics at Trinity College, Dublin, agrees. “Any individual’s [observable characteristics] will be a product of the interaction between their [genetic makeup] and the environment, in a way that makes no sense to try and separate.” However, Mitchell adds, it is possible to look for disparities in behavior between large groups of individuals and see whether these distinctions match with genetic differences or environmental factors. Another way to answer the question is to look for anatomical differences in the brain between male and female newborns, whose brain structures could help us to understand differences that are in place before cultural influences can take hold.
There are already plenty of studies showing such anatomical differences exactly where we’d expect them: regions of the brain that regulate reproductive behaviors. More contentious, says Mitchell, are anatomical differences that have been found in areas of the brain not involved in reproductive behavior. One of the more robust findings is that women, on average, have more neural fibers in the corpus callosum, the tissue connecting the two hemispheres of the brain. While these studies show that male and female brains do start out with some differences, Mitchell adds that the evidence does not refute the importance of cultural reinforcement, or even the possibility that culture can override innate tendencies. And yet, while anatomical differences in the brain may contribute to differences in psychological traits, Mitchell notes it’s extremely difficult to tie these differences to behavior.
The published literature on how men and women behave differently is abundant, but there’s reason to tread cautiously when looking at the results, says Alice Eagly, a social psychologist at Northwestern University, who emphasizes the importance of replication in research. She says that without repeating studies numerous times (and all over the world, to account for differences between cultures), it’s premature to draw too many conclusions. Studies should also use large numbers of participants to avoid the possibility of a skewed sample of the population. Most important, one must look for meta-analyses, which use data from multiple studies to draw overarching conclusions based on large amounts of evidence. Nonetheless, she says, there are certain differences that stand up under scrutiny.
Variation in spatial ability is one of the most well-established cases of a gender-based difference. A meta-analysis of more than 200 experiments on spatial ability found that there were significant differences between sexes on some spatial tasks in particular, especially the ability to mentally rotate a three-dimensional object. While different tests seem to produce slightly different results, males routinely achieve higher scores than females on 3-D rotation tasks. Other spatial abilities, such as memory of locations, show the reverse pattern, with females scoring higher than males, says Gijsbert Stoet, a reader in psychology at the University of Glasgow. Although training and confidence can play a role in closing the gap in rotation skills, the difference is so consistent, says Mitchell, that “it has psychologists flailing around trying to find the biological base.”
Another resilient, cross-national result is that girls test higher in reading ability. “In every single country that is surveyed by PISA [Programme for International Student Assessment], girls do better than boys in language skills,” says Stoet. “The fact that there isn’t a single country where boys do better than girls doesn’t prove that it must be biological, but it is a very strong hint.” Verbal fluency and access to verbal memory appear to be higher in women, but this is “a bit of a mixed picture, leaning in the female direction,” says Eagly. “It’s not clear that it’s influenced by biology—at this stage we do not understand it.”
Mathematical ability is more contested, with male scores significantly higher than female scores among students in some countries, and the reverse in others. However, representation of women at the highest levels of mathematics is still low, Stoet notes. He argues that women’s participation in certain occupations—most notably in science, technology, engineering, and mathematics (stem)—has potentially hit a ceiling, not only because of differences in ability but also interest and competitiveness. Mitchell holds the opposite stance: that there is little reason to believe that we have yet hit this ceiling, given that women in different countries have widely varying stem participation and that the rate of change in recent years has been significant. A recent study provides some support for the idea that living conditions and educational opportunities can help to close the gender gap in cognitive abilities where men have the lead, and to increase women’s advantage in the fields where they already have the upper hand (such as language).
“The behavior that is most often thought to have a biological component is physical aggression, and that’s not implausible,” says Eagly. “Surgency”—the term used to describe a set of behavioral characteristics including impulsivity, high levels of activity, and pleasure gained from high-intensity activities—is a trait that skews in the male direction in studies on children. This is a perfect example of how environment and biology can interact in a complex way, she adds: In certain environments, surgency could be the precursor to physical aggression, but in a different environment, it could become a prosocial, positive trait. On the other side of the coin, “Little girls have more executive control [control of mental processes like planning] at an early enough age to think it’s biologically caused. One thing that may be built on this is their better grades at school—we don’t know that for certain, but it’s a plausible claim.”
While these differences in cognitive skills and character traits have fairly wide acceptance, other purportedly innate differences are less well-established. One such commonly cited difference is the “people-things” dimension, which holds that boys have an innate tendency to be more interested in mechanical objects, while girls are more interested in human relationships. A famous study involving tracking infants’ eye gazes showed that newborn girls looked longer at a human face than at a mobile, while the reverse was true for boys. This study has been criticized on the basis that the researcher presenting her face and the mobile to the babies was aware of the babies’ sex, as well as other methodological problems such as a high drop-out rate among the boys and the appearance of the mobiles. “I’m inclined, only half-jokingly, to reinterpret the experiment as showing that ‘boy babies are innately somewhat more interested in transdimensional monsters than girl babies are,’” writes Mark Liberman on the linguistics blog Language Log.
So while there is some strong evidence for certain behavioral differences between men and women that hold across cultures, age groups, and educational levels, there is also evidence that social factors can play a role in mediating even the most powerful and consistent differences. These findings underline the importance of scientific approaches that examine how different social and biological factors interact rather than homing in on a single cause. In many cases, the nuanced debates on the scientific evidence are glossed over, if not lost entirely, in public communication of the results, creating the artificial polarization of “nature vs. nurture.”
An important weakness in all of this research is the exclusion of nonbinary and non-cis people, as well as the exclusion of non-Western conceptions of gender, says Lawson, who researches human sexuality and the links between sex and gender. This isn’t just a matter of inclusiveness, he argues, but a methodological problem: Claims are being made about all of humanity without taking into account important dimensions of variation. Understanding more about gender identity and what causes it to align or not align with biological sex, as well as how all these differences present in a wider variety of people, could give us insight into group behavioral differences. “Gender identity doesn’t seem to be purely cultural,” he adds, citing as an example the case of David Reimer, who was raised as a girl after a botched circumcision but resumed male identity in his early teens.
A further argument for a biological role in gender identity is the fact that “people who do not identify with the sex they were assigned at birth—and who very often identify as members of the other sex—are found in all cultures and throughout history, suggesting that the phenomenon is a part of natural human variation,” says Serano. “An even more compelling fact is that there have been numerous instances of genetically male children who were born without penises and who were raised female from birth at the suggestion of doctors. Despite not being told about their past, the majority of these children rejected the idea that they were girls and spontaneously adopted a male identity.” Although prenatal hormonal exposure has been put forward as an explanation for innate gender identity, the evidence for this is “patchy at best,” says Lawson.
Serano argues that denying the role of biology in gender harms trans people by positioning their gender as fake. “Some people who forward strict social-constructionist stances assume that, because gender is ‘just a construct,’ we can all simply deprogram ourselves and start expressing our genders in certain—supposedly politically righteous—ways.” Serano believes this particular manifestation of strict social constructionism “is harmful to trans people and others, as it denies the reality that people are heterogeneous and will differ from one another in countless ways, including our genders and sexualities.”
What Does This Mean for Feminism?
“Belief in malleability in nature, and particularly of gender, gives feminists hope for equality,” says Eagly. “If you believe that there are certain built-in traits that make women subordinate, there’s no hope for equality. Those who are in favor of ‘nature’ think that society is this way because it’s built into nature.”
Questioning this belief in the total malleability of gendered behaviors is therefore a challenging and even scary prospect for feminism. However, “average sex differences do not in any way undermine the principle of equality of all people,” Mitchell emphasizes. “If equal rights and an expectation of equal treatment under the law relied on us all being identical, we would be on very shaky ground. Thankfully, the principles of democracy enshrine the idea of moral and societal equality precisely despite the many differences between individuals.”
“The important thing to remember is that any differences referred to in research are differences in group averages, based on observations of slightly shifted, but highly overlapping distributions between sexes.” That is, the bell curve describing spatial ability for men overlaps to a very large degree with the bell curve describing spatial ability for women—meaning that although the averages might be slightly different, a huge number of women have higher scores than a huge number of men.
This means that it’s impossible to guess where an individual would fall on the bell curve based only on gender, says Mitchell. “Attributing group characteristics to individuals is not only the very definition of prejudice, it is also stupid from a mathematical point of view. You would be making a mistake to think that the women of the WNBA are shorter than most men just because women are shorter than men on average. And you would be making the same mistake thinking that women engineers are worse at spatial reasoning than most men.”
Assessing and using the evidence is a vital task for feminists, because it can help activists to identify where resources should be directed and how policy should be determined, for example, in math education: “Biological factors play a role [in abilities and interest], but environmental factors also play an incredibly important role. If you work in education, they’re the more important factors, because we can’t change biology, but we can change society,” says Stoet. His research identifies a difference in approach used by girls in mathematics—a stronger adherence to instructions, while boys emphasize creativity—that could go some way toward explaining differences in performance. This difference suggests that adapting how math is taught to girls could have an important effect on their performance. It’s also important to know which practices are ultimately unhelpful: “There’s a danger of wasting our resources on things that don’t work."
It is vital for researchers to be responsible and cautious about their methods, interpretation, and communication, says Mitchell. There is a tendency sometimes to forget the need for replication and meta-analyses and to jump to conclusions on the basis of a single study with a small sample size: “In [brain imaging research], you see a lot of studies with small samples that look across the whole brain for a difference anywhere between two groups of people. They find something, which will happen with statistically small samples, and that gets published. It’s a problem in a field like sex differences, where people latch onto findings and they take on a life of their own.”
The responsibility lies with researchers not to over-interpret their findings and hype them in press releases, says Mitchell. “University press offices carry a lot of the blame for this kind of hype, but some scientists are complicit. Good science journalists should see through that, but the number of bad studies making headlines still exceeds the number containing really high quality, solid science. I think it is the researchers’ responsibility to ensure their results are reported as accurately as possible and, equally importantly, that they are not misinterpreted or misrepresented.”
Science communicators, including journalists, have a role to play too, Mitchell adds, both in conveying the nuances of the field and in emphasizing the fact that science is a protracted debate and assessment of evidence carried out in the public eye. This means that science is always changing its mind—and that’s a good thing. People offer different conclusions as new evidence rolls in, which shows that the scientific process is working. However, poor communication of this fact, alongside premature reporting of results from small, single studies, leads to a mistrust of science, says Eagly. “The public learns to distrust, because one study shows one thing, and then the next study shows something different, because both researchers only had 10 people.”
Research in this area has huge strides ahead of it, especially when accounting for variety in gender identity, sexuality, and cultural understanding of sex and gender. Research that tries to tease apart the complex interaction of biology and society is only just getting into gear, says Catharine Cross, a lecturer in the School of Psychology and Neuroscience at Scotland’s University of St. Andrews. While exciting work in this area is a burgeoning field, there is still a significant body of research that “pays lip service to the idea of interaction, and then switches back to an argument that sounds as if it’s based on either a complete genetic determinist or blank slate explanation.”
There is undoubtedly a fierce battle for feminism to fight in the arena of gender essentialism, but adhering strongly to social constructionism puts the movement at odds with scientific consensus, placing a vital political movement on shaky ground. It also creates an obstacle in the relationship between trans activism and feminism. Perhaps it’s time for feminism to question social constructionism and stare the research squarely in the face, with some footnotes—look carefully at the sample size, understand the bell curve, and think about how the evidence can best be used for effective feminist activism—added for good measure.
Cathleen O’Grady is a South African journalist living in Scotland who reads and writes furiously about the overlaps between science, tech, international development, and politics, and occasionally remembers to go outside.