Fifty shades of grey matter: male vs. female brains
So does gender affect the brain or not?
“Of course it does, but it’s not the only factor. That’s why it’s impossible to know exactly how it affects the brain. Various incidents, such as stress, can change the form of brain characteristics completely.”
Joel claims that the brain is a “mosaic,” so there is no room for binary divisions that stem from the view that various doses of hormones create two completely different brains. She distinguishes between sexual organs, “which are either female or male for everyone,” and the brain, which she says has no such division. “Sexual organs do not change as a result of exposure to stress, while the brain does,” she says.
“If someone has ovaries, we can predict with almost complete certainty that she also has a uterus, vagina and Fallopian tubes. There is no such matching in the brain. A specific area of the brain, such as a large amygdala, does not predict anything about other areas, such as a small hippocampus (men, on average, have a larger amygdala and a smaller hippocampus than women). While there are many differences between the brains of men and women, they do not go according to a specific order, and do not match. I say that we need to stop talking about differences and start talking about matching.”
Joel, 47, started dealing with sex, the brain and gender late in life. She began her academic career by going to medical school, but left after a year to join the program for outstanding students at the university. She earned her bachelor’s degree in medical science and then a doctorate in psychobiology, specializing in the organization of connections in the brain. The main area of research that she dealt with for 15 years was neural mechanisms of obsessive-compulsive disorder.
About four years ago, she discovered that after Prof. Ariella Friedman retired the psychology department had no course dealing with gender, and decided to take on the job.
An important study on which Joel’s theories are built was conducted by the pharmacologist Professor Margaret M. McCarthy of the University of Maryland. McCarthy discovered that characteristics in the brains of male and female animals could change their form due to external circumstances such as tension or stress. “I realized that if certain areas of the brain could change from the typical ‘female form’ to the typical ‘male form’ under stress, there was no point in talking about the female brain and the male brain,” Joel says.
But even McCarthy herself was surprised at Joel’s interpretation of her research. She said that Joel had illuminated a point that was obvious, but had never been taken into account − that while sexual organs and chromosomes were binary, either male or female, the brain did not work that way.
Fighting the myth
Scientists who oppose Joel’s theories say that the influence of gender on the brain − for example, the effect of the sex hormone testosterone − is far-reaching. They claim that since testosterone levels in men’s bodies are ten to a hundred times higher than in women’s, they create a “male brain” and a “female brain” of necessity. High aggressiveness by men, involvement in crime, a strong sexual drive − all these are a direct result of high testosterone levels. High estrogen levels among women, on the other hand, lead to the fact that women are tuned to emotion and communication.
“The authors of popular science books talk about the brain as if it were a reproductive system,” Joel says. “But the brain is a flexible organ that is influenced by learning and by the environment, so many kinds of brains are created. Every human being has a neural complex individual to him.”
But the differences between the sexes, such as different talents, are very visible
“These are not talents, but rather behaviors. Various professional tendencies, different hobbies − differences are found in all these things, and all these things are influenced by the environment. But when we look at talents, abilities and psychological variables, we find almost no differences between men and women − not even in math.
“When we do find differences, the overlap is tremendous. Many times, the differences that are found in the brain are inverted logic. The hippocampus, for example, is larger in women, on average, than in men, and it is responsible, among other things, for spatial perception. So scientists say: ‘Ah, we were referring to a different kind of spatial perception.’ Everybody, even science, is captive to the myth of the difference.”
Joel fought against the myth, but it was not easy. Hardly any scientific journal was willing to publish her first article about the intersex brain. “The editors wrote to me, saying that the subject of the article was not interesting to the public. Just like that. So I sent the article to Frontiers in Integrative Neuroscience, which has a policy of publishing anything that is scientifically valid. They had no problem with it,” she says, adding that once her article was published in 2011, things started moving.
“I’ve published a few more articles that honed the original idea, I’m a keynote speaker at conferences, and several scientists are now convinced and have joined forces with me. We can say that we’ve broken through the wall.”
Last December, the journal Proceedings of the National Academy of Sciences published an article entitled “Sex differences in the structural connectome of the human brain” claiming that neural circuitry was different in the brains of men and women. Articles like that make Joel’s blood boil. The study, conducted by researchers from the University of Pennsylvania, stated that the average woman had an abundance of neural connections between the right and left hemispheres of the brain, while men have stronger connections between the front and rear portions of the brain. The researchers told The Guardian that the new discovery explained why men’s brains were wired better for perception and coordination, while women’s brains were better at social and memory skills.
“The study is scandalous,” says Joel. “Out of thousands of neural connections in the brain that were examined in the study, the scientist focused only on the hundreds of connections in which differences were found and portrayed those differences in a dichotomous way that had nothing to do with reality. Men and women have every kind of connections. What the researchers found was differences in the strength of a small part of the connections. The researchers dealt only with the differences and ignored the similarities. Also, data that could have enabled the readers to estimate the size of the difference − averages and standard deviations − that appear in almost every scientific article did not appear in this one. We were told only that there were statistically significant differences.”
The file-drawer effect
In recent months, several more new studies dealing with sex differences in the brain have appeared, but they contained no new information. One of them, conducted at the University of Cambridge, surveyed the findings of studies from the past 20 years. It found that men’s brains are eight to 13 percent larger on average than women’s. (“This was known as far back as the 19th century,” says Joel. “But there is no direct link between brain size, or regions in the brain, and function.”) Also, areas were found in the limbic system − which is responsible for emotion, memory and learning − that were larger on average in men’s brains than in women’s.
Another study, which was conducted by Northwestern University and dealt with stress and learning, found that while men’s long-term memories improved under stress, women showed no such improvement.
The American brain researcher Lise Eliot, who wrote the book “Pink Brain, Blue Brain: How Small Differences Grow into Troublesome Gaps and What We Can Do about It,” said that the media gave much attention to studies that dealt with sex differences in the brain, but was apathetic about studies that found no such differences. Eliot − who shares Joel’s opinion that there is no distinction between a female brain and a male brain, says that studies about sex differences in the brain create distorted perceptions among the public, and that the great deal of attention given to this kind of study stems from the fact that they are something sexy and fun that only confirms our stereotypes.
Eliot discovered another important thing: Many studies finding sex differences in the brain that have been held up as examples are thoroughly disproved years later. In the 1980s, for example, it was claimed that the corpus callosum − the organ that connects both brain hemispheres − was wider in women than in men, and this difference was said to explain women’s excellence in multi-tasking. But in 1997, a scientific analysis that was conducted of all the studies on the topic that had been performed until then found that there were actually no differences in the size of the corpus callosum in men and women.
Professor Anat Biegon, a biochemist and biologist by training, researcher in neurology and radiology at Stony Brook University in New York and an expert in sex differences in the brain, wrote her doctoral thesis on the biological basis of the different vulnerability of both sexes to depression. “There are almost no absolute differences between the male brain and the female brain, but only quantitative differences, like those that are found on a sequence and express a tendency,” she says. “The only substantive, irreversible difference is the hormonal regulation of menstruation in the brains of women, which is done in the hypothalamus. As far as testosterone goes, we may have to work harder to stimulate aggression in women as opposed to men, but women can also be super-aggressive in certain situations.”
Biegon adds that concern over the size and form of the brain adds no information to the discussion. “Can I look at anybody’s MRI results and tell you whether the brain belongs to a man or a woman? Not at all. In addition, the size of the brain, or of a specific part of the brain, says nothing about its function.”
Boys will be boys
About a year ago, Joel was at the center of an interesting scientific-ideological controversy at Stanford University. Her opponent was the American psychiatrist Prof. Louann Brizendine, author of the bestselling books “The Female Brain” and “The Male Brain,” who emphasizes the many differences between the two. Brizendine claims that the genetic and hormonal differences between men and women are necessary to enable the conditions and vital drives for the continuation of the species. In her books she wrote that when we try to deny the influence of biology on the brain in the name of free choice and political correctness, we fight against our own nature.
Prof. Simon Baron-Cohen, a psychologist and researcher (and cousin of the actor Sacha Baron Cohen), goes even farther, claiming that people who have Asperger’s syndrome have an extreme male brain. In his book “The Essential Difference: Men, Women and the Extreme Male Brain” he distinguishes the female brain, which is structured for empathy, and the male brain, which is structured for understanding and constructing systems.
Joel, who knows these assertions, statistics and theories well, is not confused. “The fact that there are differences in pathology does not necessarily indicate differences in the normal brain. The effect of a person’s sex on the brain depends on the environment, but the reverse is also true − the influence of the environment depends on a person’s sex,” she says. “It means this: If a man and woman are exposed to an identical environmental influence − trauma, for example − their brains may go in different directions and develop sensitivities to different psychopathologies. That is why a specific trauma can increase women’s vulnerability to depression and men’s vulnerability to autism. But the fact that there are extreme cases does not mean that men are a little bit autistic and that women are a little depressed. Is a biological component involved in these pathologies? It is reasonable to assume that it is, and there is no problem with that. But it is very likely that there is also a social component. For example, a boy who does not talk about his feelings is left alone. People say, ‘It’s all right; he’s a boy.’ That is how a situation is created in which the child does not practice that skill at all.”
Parents of children of both sexes say that there are very obvious differences. Verbal development occurs earlier in girls, for example.
“Girls do better than boys in verbal tests, but we should remember that people talk with girls more, and that affects their development. In addition, parents, and people in general, tend to use gender to explain characteristics that are ‘appropriate’ to the gender and ignore ‘inappropriate’ ones. Let’s do an experiment. What trait do you have that could be considered ‘masculine’?”
“Great − and you don’t say, ‘I’m competitive because I’m a woman.’ You see competitiveness as a personal trait of yours that has nothing to do with your sex. Name another characteristic of yours that is considered ‘feminine.’”
A tendency toward sentimentality
“And I assume that you say: ‘I’m sentimental because I’m a woman.’ So here: You’re competitive and you’re sentimental, and you’re female all the time. About a man, people would say, ‘How competitive he is,’ and about a woman, they’d say, ‘How sentimental she is.’ About a sentimental man they’d say, ‘He’s definitely gay,’ and about a slow driver they’d say, ‘All right − he’s old.’ Entire social mechanisms preserve the stereotype.”