The Incredible Brain Science of Sex and Gender (with Daphna Joel)

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Introduction – 0:00

 

BLAIR HODGES: Welcome to Relationscapes, the podcast where we explore gender, sexuality, race, and more in order to make the world better for everybody. I'm journalist Blair Hodges in Salt Lake City and our guide in this episode is neuroscientist Daphna Joel.

DAPHNA JOEL: No two brains are the same. Each person has a unique mosaic of male-typical and female-typical characteristics So in the brain we can say that we are all intersex, or I use the word mosaic."

BLAIR HODGES: All of us grow up swimming in gender stereotypes: men are from mars, women are from Venus. Women are emotional and men are rational. Women's brains are like spaghetti and men's are like waffles. And that’s a real one that some people out there are teaching, you can google it.

But secretly and not so secretly, a lot of people feel like these binary cliches actually don't fit. Daphna Joel is a neuroscientist who wanted to know what the science actually says about this stuff. And when she looked at real brains, she found something far more interesting: each of us carries a unique mix of traits, a true mosaic that defies the old binary.

Daphna Joel is here to talk about what her research reveals in her groundbreaking book Gender Mosaic: Beyond the Myth of the Male and Female Brain.

 

Politicized Science – 01:46

 

BLAIR HODGES: Daphna Joel, welcome to Relationscapes.

DAPHNA JOEL: Great to be here.

BLAIR HODGES: I wondered, when I started reading this book, if you grew up believing there were male brains and female brains and that they were different.

DAPHNA JOEL: I wouldn't say I grew up with it, but I was aware of this myth regarding the male brain and the female brain, or that men are from Mars, women from Venus, and other books like this.

BLAIR HODGES: Did it seem right to you at the time?

DAPHNA JOEL: I never felt it really applied to me. I didn't feel like I belonged to one of these very stereotypical categories.

BLAIR HODGES: So from your own experience, you weren’t feeling those categories.

DAPHNA JOEL: Right.

BLAIR HODGES: There’s an idea in many people’s minds that science is unbiased and objective and that it's not involved with social or political concerns, but your history shows us that isn’t the case. Back in the 17th and 18th centuries, Enlightenment thinkers started arguing that all humans were equal by nature, regardless of sex. And that was a problem for a lot of people because women were seen as the weaker sex. They were expected to play certain roles in society. So they wanted to resolve that debate. And you say you've been impressed with the creativity that went into using science to serve that social agenda.

DAPHNA JOEL: Yes, you describe it very well. And I would just add that before we had science, we had a religion explaining reality to us, both the physical reality, but also, of course, the social reality. And science tried to explain not just the physical reality—and this is usually how we think of science as explaining physical reality—but also social reality.

And they also tried to keep social order, even though, as you said, it wasn't aligning with ideas of equality, et cetera. And they have been using science not just to justify inequality between men and women, but also between other groups like Black people and whites and the poor and the rich, et cetera.

And at least in the case of sex, it seems like a very easy task, because they knew already that the brain has something to do with intelligence, and that they couldn't measure the brain directly, but they could measure the skull. And it's very easy to see that men have, on average, bigger skulls than women.

So this seemed like a very easy explanation: men have bigger brains, they are smarter, and this is why we have this social order. And the difficulty was, they looked around at nature and there are some examples of animals with much larger brains and skulls than humans, like whales and elephants, et cetera. And obviously, the people that wanted to explain how men are superior to women didn't want to claim that elephants are superior to humans. So they had to find a solution.

And they did. They said, okay, what's important is not the absolute size of the skull, but the relative size of the skull compared to the body. And when you look at this ratio, humans did have a higher ratio than whales or elephants. Okay, they were relieved. But then they noticed that actually, women have larger skulls in comparison to the size of the body.

BLAIR HODGES: [laughs] Uh oh. That solution didn't work.

DAPHNA JOEL: Right. And now if science was really so unbiased or apolitical, then you would think they would say, okay, so women have larger ratio of skull to body size, then obviously women are the smarter sex and we should simply just change social structure to reflect this in order to have a better society.

Well, this didn't happen. And, you know, they had to find a different solution, and they did so. I didn't personally do the historical research, but several very interesting scientists did, like Londa Schiebinger from Stanford. And when you look at the history, what you see is that each time that the explanation of the inequality ran into problems, they simply change the explanation. And you see how this goes. It's very obvious that they have a particular aim: To explain why men are better than women. And then it's just the details that are changing.

And this is even true today. So what is changing is the content of the myth. And it changes because, you know, neuroscience is progressing and we can measure the brain. We can measure very sophisticated things within the brain. So the details are always changing, but the end or the conclusion is always the same. And this is explaining why the brain or differences in the brain must be manifested in a way that explains or justifies current social or social injustice or inequality.

BLAIR HODGES: Right. So they started off with the skulls. That explanation led to a dead end. Then you talk about French physician Paul Broca, who is a famous scientist, said to have discovered “Broca's area” in the brain which deals with speech. I remember learning about that in a high school psychology class. They next started looking at the actual brains. So looking at the shape of brains, and then they started looking at ventricles to say, oh, well, these ventricles in the brain seem to be different in male and female bodies.

And in the book, you write that what's worrying—[laughs] I mean, we can sort of chuckle about this history because it's so obvious when we look at the past what they were doing, but as you said, it's still kind of happening today.

And you say is it's worrying that sex differences are still being used to justify gender equality today, and that it’s a little bit more common than justifying racism or classism using physiology. There are still some people that point to physiological differences to justify racism and classism, but it seems to be less common to do that than it is for sex and gender.

DAPHNA JOEL: Yeah, I think it's. And again, it's important to look at history and realize that, actually, sex is the only thing that is still legitimate to talk about the differences in the brain as explaining inequality in social life between men and women. And we wouldn't do it for any other social class, even though there are many differences in the brain.

So if you compare the brain from people born in China and, people born in the west, there are differences between their brains. But no one would claim that Chinese people are better in mass because of something in the brain or are worse in something else because of something in the brain or the other way around.

 

Real Differences Between Male and Female Brains – 08:19

 

BLAIR HODGES: Let's talk about some of those real differences, because as you said, there are some differences in male and female brains that scientists today might point to hundreds of differences. Give us some examples of what the differences are.

DAPHNA JOEL: So the first and main difference is a difference in brain size. So this was known already in the 17th century that this was true. On average, men have larger brains than women, and it corresponds quite well with the body size, although it's not linear or a direct linear relation. So everything in the body of men is on average, larger than in the body of women, and the brain is one of them.

The first question is, how you take this into account, because it's not really interesting, because everything within the brain is also, on average, larger in the brains of men. So one thing that you do is you take this into account and then you ask, are there differences that go beyond this difference in brain size?

Or in other words, if I take a brain, a brain of a group of men and a group of women, that the average brain size is similar, so it will be smaller men and larger women in terms of body size, would we still see differences? And if we do, then we can say these are sex differences.

It has nothing to do with overall brain size. So when you do this, you find very little differences, and they are much smaller, but you do find still differences. So it can be a difference in the size of a specific region in the brain, which could be, on average, smaller or larger in men or women.

It could be density of specific type of neurons in a specific region. It could be some differences in the microstructure of the brain. How the dendritic trees organize and things like this. So of the many things that we can measure in the brain, we can find differences, but the differences are mostly small with a lot of overlap.

BLAIR HODGES: I think that overlap is what really stands out to me, because if people really were to believe that brain size is determinant of intelligence, for example, if you got a bigger brain, you're smarter. Well, there are some women's whose brains would be larger than some men's brains, right? So we would have to say, okay, well, if it's just about brain size, that means we do have some women who are a lot smarter than men because of their brain size.

In other words, breaking it down by sex doesn't work even if we accepted the presumption that brain size was the key factor.

DAPHNA JOEL: I mean, you could do this again to take similarly sized brain and then see if this works. And a good example for this is Albert Einstein, who is considered quite smart. He used to be very smart and he had a very small brain. And again, this is not surprising because he was a small man. So he had a small brain. But obviously, how smart you are and how intelligent you are has very little to do with how big your brain is.

And you mentioned the ventricles. So larger brains also come with larger ventricles. These are the empty spaces in the brain that are filled with fluid. Does that mean men are not as smart because they have these big holes in the brain? [laughter] No, this is all has nothing to do with the reality of how the brain works. And as I said in the book, you know, women do just fine with a smaller brains. Men do just fine with a larger ventricles. You know, we are all okay!

 

Brain Myth Buster – 11:43

 

BLAIR HODGES: Right. And then as you said, there's also some overlap. There might be a woman who has larger ventricles than a particular man did or whatever. What are some other examples of the way that popular media today talks about differences in male and female brains? In the book, you discuss a few examples that you see in the media, and you're like, “oh, no, here we go again with the Mars and Venus situation.”

DAPHNA JOEL: Okay, so there are several biases or common misconceptions. The first is that usually we think of differences in the brain as innate. So when we find a difference in biology or in the brain, we think that this is an innate difference. And of course, a difference in the brain gives us no information about the source of the difference, or in other words, about the nature/nurture question, why we have this difference. This is the first very common misconception.

Another thing is that we think of differences between males and females in the brain, and in anything else, in binary terms. So even when there is large overlap between males and females, we think of the differences as binary, as, like, men are this way, women are that way. Which is never true in human brains.

And the third misconception is that within the binary framework, we think differences add up consistently within individuals to create two types. And this follows the logic of the genitalia. If you think of male genitalia and female genitalia, indeed this is the case; male genitalia is characterized by having only male typical genital organs.

And similarly for female genitalia. And we use this logic when we think of brains. And I think this is why often scientists, when they find differences between men and women, they assume that what's typical of the male brain is to have male typical brain characteristics, and what's typical of the female brain is to have female typical brain characteristics.

And what we've shown in many different studies of many different things we can measure in the human brain is that this is not the case. So in the brain—and this is in contrast to the genitalia—what's typical of human brains is to have both male typical and female typical characteristics. So if we were using the terminology that we use for genitalia, we have male genitalia, female genitalia, and then some people have intersex genitalia.

So in the brain, we can say that we are all intersex, or I use the word “mosaic.” Each person has a unique mosaic. No two brains are the same of male typical and female typical characteristics.

BLAIR HODGES: The book's so helpful, how it teaches media literacy, because you want to remind people when they see a headline that says something like, “Men are better at multitasking than women” or whatever, that we really should take a look at what those studies are, because a lot of times those claims are the result of maybe like one experiment that somebody ran at a university someplace and the results aren't being replicated.

They present one study as representative of everything. And so being aware of what's behind the claims in the media is really important, especially when it comes to these headlines, because they'll grab your attention, right? “Men sleep better than women” or this or that. It's always this binary presented as scientific fact. But when you start looking at the studies behind them, you say that it's usually small, limited studies. These things aren't being replicated. And it's just kind of some headline-grabbing stories.

DAPHNA JOEL: This is true. But I want to stress that this idea that each brain is a unique mosaic of characteristics, this is not a result of this problem that you rightly mentioned, but this is actually how sex affects the brain. And this idea of the mosaic, I came up with it from reading a lot of animal studies which looked at sex differences in the brain, and what I saw in these studies is that sex differences, for example, in the brains of rats can be opposite under different conditions. So what's typical of males can be typical of females, and what's typical of females can be typical of males under a different set of conditions. And these interactions between sex and many other factors is different for different brain features.

And this is why sex differences in the brain mix up instead of adding up consistently. We recently showed this in the rat brain, that you can see these mosaics. Most rats will have a mosaic of male typical and female typical characteristics. This is really important.

Again, when you go back to what you mentioned, this is one of the reasons why different studies are not consistent. Because differences that you see, for example, in the brain between men and women can be different under different conditions. For example, because of the amount of stress a person has faced. Probably many sex differences would be different now because of the long exposure to stress, which affects the brain and interaction with sex related factors.

 

Brain Plasticity and the Nature/Nurture Question – 16:53

 

BLAIR HODGES: Right. In fact, let's talk about brain plasticity a little more. We're touching on it already, so define brain plasticity for us.

DAPHNA JOEL: I think this is the most interesting characteristics of brains, is that they can change in response to experience, in response to the environment. And this is what makes us such creatures that are specifically built for learning. This allows us to learn from experience because our brain keeps changing as we go in the environment, as we experience things, as we behave.

So brain plasticity can be changes in the short timescale, changes in synapses, strengths, changes in the organization of dendrites, and it can be long term changes in which neurons are participating in which action, et cetera. So you can see the differences also with MRI in humans, following training in very simple tasks that, for example, involve the fingers, then you can see changes in blood flow in the brain in the fingers areas.

So we can see this. And of course, in animals, we can look at more sophisticated or more microscopic things and see these kinds of changes. So many features of the brain can change in response to environmental and experiential events.

BLAIR HODGES: This is where the nature versus nurture puzzle can really be looked at. There's a study that you talk about in the book about London taxi drivers, that they did these studies on London taxi drivers and found that they had huge hippocampus areas of their brains. So if we didn't think about nature versus nurture, we just happened to pick a bunch of taxi drivers for our study and looked at them, and we took a bunch of taxi drivers who are men and then compared them to a bunch of women, we might conclude, wow, men have huge hippocampi compared to women and assume that it's based on sex, when in reality you say, no. If you look at what the London taxi drivers have experienced in their lives, the nurture side of things, this explains where the difference in a hippocampus comes from.

DAPHNA JOEL: Right. And this is really an interesting experiment that they did because in the beginning, what they found is a difference between London taxi drivers and people that are not London taxi drivers. And just finding the difference is not enough to know the source, because it could be that only people with very large hippocampus should become a taxi driver because they need to memorize all the streets.

BLAIR HODGES: Yeah. Like that's why they became taxi drivers. [laughs] They were born with it.

DAPHNA JOEL: And usually this is how, you know, when you look at sex differences, this is usually how you use it. You say, okay, we see this difference, and this is why men are better at math, or they are, you know, more in STEM studies and women are something else, like more empathic.

But what they could do also, I think in the second study, and I hope I remember correctly, they compared younger and older drivers. So people with more experience and less experience. And then, although it's not a proper experiment, but it's much better and they could see that indeed it correlates with the time that you were driving. And this suggests, strongly suggests, that it is the driving experience that is driving this difference or the size of the hippocampus.

BLAIR HODGES: Right. And this is where nature and nurture comes up when it comes to gender. Because people can assume that boys are certain ways and girls are certain ways. And so in the ways that they're raised, in the ways that society, society interacts with them, that can actually shape physical brain features, that we can actually be impacting what we assume are sexed brains, when in reality culture is helping to make that happen.

DAPHNA JOEL: Right, so we can talk about “gendered brains” instead of sexed brains.

So the nature nurture debate, we can talk about why we are so obsessed with this, but let's leave this aside for a minute. It's important to understand that this is another binary that doesn't really exist. Because at least for the brain, development is part of the nature of the brain.

So there is no point of thinking about brains outside of nurture. So brains are developing. We are not born with a fully functioning brain, it has to go through so many developmental stages until after the age of 20. So we are talking about many years of development of the brain. And so obviously the interactions with the environment are part of how the brain is supposed to be built up. Brains without environment, they wouldn't be functioning well.

And it's not the same for every organ in our body, but specifically for the brain. So first, the nature/nurture is problematic in this debate, as if these are two independent processes.

Now to know whether a difference that we see between men and women in the brain is a result of nature or nurture is almost impossible because we cannot disentangle the two. The other thing is that if we found differences in the brains of neonates, newly born babies, then we can say, okay, this is innate, this is not the result of the environment. And I was looking for many years for a study because I knew they were working on this. So they had a study of many hundreds of newborn babies. And I was looking for the results because I wanted to analyze the mosaic and see whether babies are already born with a mosaic brain. Because we knew from animal studies that manipulations that are carried out already in utero can do this reversal of sex differences.

When finally the study came out, it turned out that they have very few sex differences in the brain. So the main difference between the brains of male and female babies is again the size of the brain. Once you take this into account, almost no differences. So we couldn't do the mosaic analysis. Most of the differences in the human brain, they appear only later in life, around puberty and later.

Now I want to stress this doesn't mean that there are not innate or if you want, you can better say pre-programmed differences. If you take the difference in the form of the chest of the males and females, the difference appears only in puberty, doesn't mean that it's not preprogrammed. This difference doesn't mean that this is environmental.

So the fact that differences appear later is not a proof that they are environmental.

But then you cannot disprove that it's not environmental. So we don't have good evidence for innate or pre-programmed sex differences in the human brain, but we do have many types of evidence for environmental effects on the brain. So there is lots of evidence to suggest that many of the differences that we see between the brains of men and women are the result of gender. But this doesn't exclude the possibility that sex also contributes to some of these differences. And again, I want to stress from animal studies, we do know that sex related factors, especially sex related hormones like testosterone, progesterone, estradiol, they all affect many aspects of the brain. And this is probably also true for humans.

The point of divergence between brains and genitalia is that in the brain, how these hormones affect the brain depends on other factors and in fact can be opposite under different environmental conditions. And this is a result why we don't have male and female brains, while we do have male and female genitalia. It's not because sex does not affect the brain, it's because how it affects the brain depends on so many other factors. And this is why these effects do not add up to two types of systems, male brains and female brains.

BLAIR HODGES: This is where it gets so tricky, because some people want you to just say, yes, there are male brains and there are female brains, and they are different. And other folks might want you to just say, no, there's one type of brain and that's it. And your picture is more complicated than both of those things.

You're not saying that there isn't a male and female brain—or you're not saying that it's completely different or completely the same.

DAPHNA JOEL: And again, because this is the question that people are concerned with, is within the binary framework. And within the binary framework, there are only two options. Either we are the same or we are different with different meaning, belonging to two types.

And what we show is that we are not the same and we are not different in terms of belonging to two types. In fact, each brain is very different from any other brain. And we managed to show this using many different machine learning algorithms, et cetera. What's important here is sex category. So knowing someone's sex category, for example, that I'm female, doesn't give you almost any information about the specific structure of the brain and also about similarities and differences between someone's brain and someone else's brain.

So the right answer to the question, are we the same or different? Is that everyone is different. And sex category provides very little information on how two brains are similar or different.

 

Looking at Brain Scans – 26:14

 

BLAIR HODGES: Looking at brain scans, I wanted to ask you about that. So could we look at a brain scan and guess pretty well what the sex of the person is?

DAPHNA JOEL: We can actually do this and the accuracy would be quite good if we didn't correct for brain size. So basically you would say if it's a large brain, probably it's a male brain from a male, and if it's a small brain, probably it's from a female.

If you correct for brain size, the accuracy drops. So it would be around 60%. Considering that 50% is chance is not very good, but it's better than chance. But the interesting question is a reverse prediction. So usually, you know, if I want to know if you are male or female, there is no point in putting you in the scanner, paying, I don't know, several hundred dollars and then guessing with 60 or 70% chance whether you are male or female. [laughter]

You know, I look at you, I have a very good, you know, pretty good guess that you are male. So, and the question is the opposite. So I know that you are male and if I'm not sure, I can just ask you again, I don't need an MRI scan. And then the question is, what do I know about your brain?

And the answer is, very little. And again, and this is different from the genitalia, because knowing that you are male, even though I haven't seen your genitalia, I know a lot of information about your genitalia and especially I can guess, you know, have a good guess of what type of genital organs you have and even more so, what type of genital organs you do not have.

When it comes to the brain, I have no information. I don't know which features of your brain would be in the male typical form and which would be in the female typical form. No idea how similar your brain would be to mine, nothing. So it's the complete opposite.

And this is really important because again, usually within the binary framework, when we hear that sex-related factors affect the brain, that there are sex differences in the brain, et cetera, we immediately think that this means that there are two types of brains, that knowing someone's sex category provides a lot of information about their brain.

This is true within a binary framework. But in the brain, because of the mosaic, this is not true. And again, I want to make this distinction. Sex-related factors affect the brain. I guess that your testosterone levels right now are higher than mine. This affects our brain. But how it affects our brain depends on many, many factors.

And this is why in some domains we are very similar now in how our brain responds. In others, we are different. So this is an important thing to remember.

BLAIR HODGES: Okay, so it's like you could look at a brain scan and have a pretty good idea what the sex of the person was, but you could look at a person and not have a pretty good idea and be able to predict what that person's brain structure. You could look at me, I'm a bald guy, I have facial hair, my voice sounds low.

But based on those things, you still would not be good at making a prediction about what my brain structure might be because of that.

DAPHNA JOEL: Right. I wouldn't be able actually to predict it. It's not a good prediction. Just I really have no information. The only thing that I could say that probably you have more male typical features in your brain than female typical features. This is not very helpful because 51% male typical features and 49% female typical features would still fit in.

And also the question is, which features are in the male category?

BLAIR HODGES: Right! And it would be ignoring all the female typical features that I have. It's sort of just dismissing all of those and assuming, okay, well, he's got a male brain and we can just forget about all the female typical features that he has.

DAPHNA JOEL: Right.

BLAIR HODGES: You use the idea of a blind date as a way to think about this, talk about the blind date example, because this really helped me grasp things.

DAPHNA JOEL: Let's say, you know, we are going on a blind date and we know that our partner for the blind date is going to be male. So again, this gives us a lot of information about his reproductive system perhaps, but doesn't give us any information about his brain.

And specifically, and again, we can maybe talk a little bit about gender, this can help. So I can guess that if he is male he will have more masculine characteristics than feminine characteristics. But this is not very helpful because are his masculine characteristics being aggressive and watching a lot of porn, or are his masculine characteristics being great in sports and maps well?

And I would also know that he will have some feminine characteristics. And again, it's really important which ones. Would he be talking too much or would he be empathic and warm? So it is the combination of characteristics of masculinity and femininity within this specific data, this will determine whether I like this person or not and whether it can work between the two of us.

And it depends not only on the specific combination of masculine and feminine characteristics, but also how that combination matches mine. Maybe both of us really like sports or we'll have a great time together. Although for him this is a masculine characteristic and also for me, but it's, you know, gender atypical because I am a woman.

So the question is how two mosaics match. And we cannot know the mosaic of another person just by knowing this person’s sex category.

 

Hormones, Gender Identity, and More – 31:29

 

BLAIR HODGES: So sex does play a role in brain structure, as you've mentioned, but it's not the only factor. And the kind of differences you're looking at between brains can involve things like the density of, of different brain regions, not just size, but like their density, how thick are they, how heavy are they, how much matter is there. Differences in neurotransmitters, differences in receptors, and then plus all of the external events we encounter—how our parents were treating us, the stress that we're put under, the stress that our parents were put under, that our father could have been put under and that affected his sperm, or that a mother could have been put under, that affected an embryo in the womb.

So there's so many different factors and also hormones, testosterone and estrogen can make a difference. Talk about that. And I'm kind of interested in how this connects to trans issues. People might have questions about what we know based on trans identities and brain structure.

DAPHNA JOEL: So what we know is that sex-related hormones like testosterone, estradiol, progesterone, affect our brain. And I want just to mention that we all have all these hormones. So often people treat these hormones as male hormones, female hormones, which is very misleading because we all have all the types of hormones. They are produced in the ovaries, in the testes, also in other tissues of the body.

The level of these hormones fluctuates continuously within the bodies of females, within the body of males. So again, just to get rid of the binary, when we talk about sex related factors or sex related hormones. And these hormones affect the brain. And we know from animal studies, not so much from human studies, that they can affect many aspects of the brain, also of the developing brain in utero and also later in life.

And it also affects our brain. So women who are ovulating and they experience the changes, these affect their brains. Pregnancy and following delivery, all these changes affect the brain, and women can experience this.

But also, for example, postpartum, we have a very large change in hormones, and it affects and causes labial mood. So women are more emotional. But whether a woman would experience postpartum depression or would be euphoric, okay, so you can see that the hormones do not determine the outcome. The outcome is a result of interaction between these drastic hormonal changes, but also probably gene predispositions, the environment, whether the environment is supportive or not, and other things.

So, yes, sex related hormones affect the brain, but how they affect the brain depends on many other factors. And this is why we are not all having the same effects. And it can even be opposite for different people.

BLAIR HODGES: Right. So you can have a trans individual, like a trans woman who is really emotional and sort of stereotypically feminine, or a trans woman who's stereotyping more of like a tomboy. A tomboy trans woman. There are differences between all these different gender identities, and we see this across the board.

DAPHNA JOEL: So I wouldn't say this the way you said it. So for trans, I would say two things. First, we do not know why some people are cisgender and why some people are transgender. And we looked at the brains of transgender individuals and found that also their brains are mosaic. So trans people, like all other people, they have a mosaic brain, at least in the things that we measured.

Now, when trans people take hormones, and I want to remind us all that also cisgender people take hormones, specifically, many cisgender women take hormones because, like birth control pills, there are hormones. So when humans take hormones, regardless of the reason, this affects their brain. And some of these effects can be measured.

But again, there have been some studies on the brains of transgender individuals before and after they have been starting to take hormones. And you can see differences. But again, you see a lot of variability, because if you take, for example, testosterone, how it will affect your brain depends on other factors. So it's not the case that all trans individuals would have the same response to testosterone in the brain.

BLAIR HODGES: Yeah, that's helpful. There's a quote that I'll read from the book that kind of sums all this up. You say, “People who learn about my work sometimes mistakenly conclude I'm claiming there are no sex differences in the brain. I hope by now to have made it clear that that's not the case. Sex does affect the brain, and there are average differences between females and males in many brain features. But because of the interactions between sex and so many other factors, the effects of sex, that is being female or male, are mixed up in a unique way in the brain of every individual.”

DAPHNA JOEL: Well, well said.

 

Binary Breakdown – 36:24

 

BLAIR HODGES: [laughs] It is, it is, it is well said. Again, it's something that I have to really work to wrap my mind around. Do you find yourself sort of repeating yourself, like, what does it feel like to be a researcher on this topic when so many people have such strong feelings about it?

DAPHNA JOEL: So actually I was surprised. I was expecting, you know, that people would throw tomatoes at me or something like this. [laughter] But people really accept this very well. And I put some thought into this to try to understand why people really like this idea. And what I think is—And usually when I talk about the brain, I also talk about gender because it's easy, because we don't know much about our brains. But everyone can name a few masculine and few feminine characteristics of their own. And our studies show that everyone is like this. So everyone has masculine and feminine characteristics.

And what I think is that it's actually easy for people to accept. This is because it fits well the theory of gender. So everyone knows that there are gender differences. You look around in the world and there are gender differences. There are more, you know, male basketball players and female basketball players. There are more men who are interested in, I don't know, football than women. And you know, and we can name in each culture it may be different. In Israel, no one watches football. We, you know, our football is your soccer.

But anyway, so the differences may be different in different cultures, but everyone can name masculine and feminine characteristics. And the mosaic doesn't say that men and women are the same. It says, yes, you are right, there are differences. I don't know why the differences are there, but there are differences.

The mosaic also say that every person has both feminine and masculine characteristics. Now, people know this about themselves. What they do not know is that everyone is like this. And I think learning that everyone is like this is actually quite reassuring, because we live in such a binary social system where some people do not feel comfortable in their gender atypical characteristics. And when they learn that everyone has gender atypical characteristics, maybe they are more at ease with the fact that they also have some gender atypical characteristics. So they don't have to add much to the gender theory of the world to accept the mosaic.

But if you really understand the mosaics deeply, what you realize is that the binary framework—this is where the problem is. This is what is wrong. So it's not about having differences between men and women in specific features. It's about thinking that men and women belong to two types, and this is not true. And this is why I think people, they don't usually have a hard time accepting this.

BLAIR HODGES: That's Daphna Joel. She's a professor of psychology and neuroscience at Tel Aviv University, one of today's revolutionary specialists on sex, brains, and gender. We're talking about their book, Gender Mosaic: Beyond the Myth of the Male and Female Brain.

 

The Mosaic Metaphor – 39:22

 

BLAIR HODGES: Okay, let's unpack the mosaic metaphor a little bit more. You've been talking about the mosaic all along, and this is something you've borrowed from the world of art. Describe what a mosaic is and how you came to bring it over as a metaphor for your research.

DAPHNA JOEL: Growing up in Israel, which has some very ancient history, mosaic is very common. When you go in different ruins and stuff, mosaic was a very common art. And I later learned that it's not as common in other parts of the world. So for me, the idea of a mosaic, of creating a picture from many different pieces and each piece in a different color, this was a very intuitive way of thinking about our findings with regard to brain and gender.

BLAIR HODGES: So it's this art with colors in a different array. And in your book, you've got this amazing spread. I believe that they're brain scans that you've put side by side. And on one page there's women, and on the other page there's men. And you just see all the different colors there that, again, it's not like on this side, it's all the same color, and on that side, it's all the same color. We just see this blend across both images. That shows a lot of difference. There's a lot of difference between male brains. There seems to be as much difference between male brains as there is between male brains and female brains.

DAPHNA JOEL: So I'm really glad you brought up these images because, you know, we are talking and people do not see the images, but I really encourage people to go and look at these images because, you know, one picture was thousands of words. And this is a very good example of this, because what you can see in these images, which show in each line a single brain, so it's actually the volumes of 116 regions in each brain.

And what you see at the group level, you can see the differences between men and women. And we use a color code of green to yellow between large and small and what you see is that at the group level, there is more green at the women's side and more yellow at the men's side.

But what you can also see, and exactly what you said, is that brains are rarely all green or all yellow. Instead, each brain is a unique combination of green, which is more common in women, and yellow, which is more common in men. I think this is important because, again, within the binary framework, it's really hard to understand how it could be that there are group level differences, but there are no two types.

When you look at these images, you get a new idea or a new model of how to think of sex in the brain, because you can see the group level differences, but you can also see that brains do not come in two types. Brains are not yellow versus green.

 

Harmful Gender Stereotypes – 42:09

 

BLAIR HODGES: You say that treating females and males as if they belong to two distinct, predictable types can result in a lot of annoying sexism, which is a problem. But you also suggest it can be bad for our health. So talk about the effects of getting our ideas about brains wrong. How does that affect our health?

DAPHNA JOEL: So it's not just about our brain, but the binary framework. The problem is that we see differences between men and women, and immediately we think of them within the binary framework, as if men and women belong to two types.

So, for example, people find differences in the cardiovascular system, and then they talk about men and women being so different, as if they have two types of cardiovascular systems. And of course this is wrong.

 And then you have some men coming into the emergency room with female typical symptoms and they are misdiagnosed because of this belief that, you know, men do not have this. And another example is depression, and even postpartum depression, which is considered a female problem. But many men, many new fathers, experience postpartum depression, even though, of course, they weren't delivering by themselves. So a man suffering from postpartum depression would be misdiagnosed. No one will even consider the possibility.

So this idea that some of the gender differences that we see in health outcomes or in health conditions are binary—so men have it, women don't, or the other way around—causes a lot of problems to the gender or sex category, who typically do not show this as commonly as the other group, and then people are misdiagnosed.

Another example is, for example, breast cancer in men. So this is obviously much rarer than in women. But men that do suffer from it are more likely to die of this because usually they will be diagnosed much later, because no one considers a possibility that they could be suffering from breast cancer.

BLAIR HODGES: You also mention medicine and how dosages can be different and how bodies might need different doses. And when we're assuming this binary, it can cause problems with prescriptions.

DAPHNA JOEL: So for a long time, many studies have been done only on males, and this is a problem, assuming that females are just like males. And then therefore, if we study men, we can conclude that everyone is like this, and this is actually wrong. And then they switch to the other side of the continuum.

And from the very important demand that both men and women are included in studies, they switch to assuming that men and women are so different as if they belong to two types. And one example is dosing. So there is Ambien, a very common sleeping drug, and women suffered with higher rates from some side effects.

But it wasn't that all women suffered from these side effects and all men didn't. It was just a quantitative difference and they cut the dose for women in half. Now this is a problem, because later it was found that it's not a sex difference, but it relates mainly to the difference in body size.

So, for example, big women would actually need the “men's” dose, if you want, and smaller men would need the “female” dose. And this binary thinking relating this to sex rather than to actually looking for the sex-related variables, in this case body size, and then giving you the dose you need according to your body size and not according to your sex category.

So sex category, and this is important, sex category is rarely a cause of some sex difference. Usually it's other factors, some factors that are directly related to sex, for example, se- related hormones. But it could be other things like body size, height, muscle to fat ratio, level of exercise, physical exercise. And a good example that I like to give is let's think that you have heart problems and you come to your doctor. And we know from medicine that things that are important are whether you were smoking and how much physical activity and whether you are overweight, etc.

So assume that instead of asking have you been smoking? How much have you been smoking? Are you doing physical exercise? Let's put you on the scale and see whether you're overweight or not. Instead of this, we would just look at you and say, okay, you are male, so obviously you have been smoking, you are doing a lot of physical exercise, and I'm not sure about your body weight.

Obviously this is bad medicine. So using sex category as a proxy for the actual factors that matter for your health condition is not right, we should look for the actual factors and then measure them. Maybe we can affect them. Because I can ask you to stop smoking or start to do more physical activity. I wouldn't ask you to, you know, change your sex to treat your heart problems.

BLAIR HODGES: And we kind of do some of this ourselves. You talk about how doctors do this. I'm thinking about your friend Lisa. She has three daughters. And you talk about how when they were growing up, she would say how girly they were. “Oh, they're such girls.” But they were all different from each other. The oldest was really affectionate and dreamy. The second one was sort of a born caregiver. And the third daughter loved to dress up and act. And you say the daughters also had some stereotypically boyish characteristics, but these were mostly overlooked. Instead she was like, look how girly they are. So she was just identifying these particular things about them and put them in the girl box and then they kind of became a two dimensional version of themselves.

We kind of selectively look at people and assume things about them based on these stereotypes.

DAPHNA JOEL: Right. So this goes to a very interesting question, for me at least. If everyone is a mosaic, why don't we see people as mosaics? And instead we see them as if they belong to two types and we look around and we see men and women, we don't see mosaics.

And this is interesting and what you just described, this is one of the reasons. So, for example, if I have a boy and he really loved to play football, I would say, yeah, of course he's a boy, he loves football. But then if he really likes to cook, I wouldn't say he's a boy and this is why he loves to cook. I would say, you know, he likes to do things with me and I love to cook. So he likes to cook. And maybe I also have a girl and she also is a great cook, really loves to cook. And I would say, yeah, obviously she loves to cook.

She's a girl and she also likes to play football. And I'll say, yeah, of course she takes after her brother or after her father. So we can see how we think of gender-typical characteristics as if they are the result of our sex or gender, and we ignore gender atypicality or we attribute this to other factors and this is how we manage to keep the stereotypes.

And one good example is if you have a very active girl, young girl, you would say she's a tomboy. So you actually see an active girl, but you reinforce the stereotypes that boys are active. Because you say that she is a tomboy. No, she's not a tomboy. She's an active girl. And girls can be active!

 

Toward a World Without Gender – 49:33

 

BLAIR HODGES: And this gets to your last chapter of the book, which is called “Towards a World Without Gender.” That chapter title is going to set off alarm bells for people who think that without gender, the social order will come crumbling down, that people will stop having babies, and that no one will know what's going on.

Some of these fears are rooted in religious beliefs and some of them aren't. Some of them are just rooted in, “this is the way the world is.” In fact, a lot of people think this is just science. There are men and women, and that's just science. Don't you know?

What do you think about when you're saying, “towards a world without gender”? What do you mean by that? How do you respond when you get a response of wow, that would just cause mass hysteria.

DAPHNA JOEL: So first I want to stress that when I say a world without gender, I mean gender in the sense of a social system that ascribes meaning to being female or male. And this is important because we use gender for many other things, like, for example, gender identity. So I'm not talking about gender identity, but I'm talking about gender as a social system.

And a world without gender is a world in which there is no a priori meaning to the fact that one has female or male genitalia. We don't have different expectations of them, we don't dress them differently, we don't expect different things from them, et cetera.

And people often ask me whether in a world without gender there would still be group level differences between humans with male and female genitalia. And I say that I don't know. And we talked about this a little earlier, I really don't know whether in a world without this social binary, social system, there would be differences. There could be or not. And I would expect actually that in different cultures there would be different differences.

But what I can say is that in a world without gender, we wouldn't care. And this is important thing, we wouldn't care. And what I want to say is that also today we shouldn't care. So, for example, if I love martial arts, which I actually do, why should I care whether martial arts is more common in humans with male or female genitalia?

I don't care whether it's more common in people with blue or brown eyes. And the reason that I don't care is not because I read many scientific studies showing that there are actually no differences between humans with blue and brown eyes in how much they like martial arts. The reason I don't care is that eye color is not considered an important social aspect or social category. And the same should be for sex differences.

So we shouldn't care if I love martial arts whether this is more common in humans with male or female genitalia. Why would that even matter? So the fact that there is or there aren't gender differences in whatever shouldn't affect me. And for those people who think of gender and the gender social order as a direct consequence of sex, I say if this is what you believe, you shouldn't care about getting rid of gender because it would reemerge anyway.

So you are the first that you say, yeah, yeah, you know, you know, there is no problem. We don't need to raise boys to be boys and girls to be girls. There are males, there are females, they will just grow up this way.

And if this is really hard to grasp, imagine you have a dog. You don't teach your dog to become a dog. He's a dog, she's a dog. They will become dogs. So if you really believe that gender is a direct consequence of sex, you should be the first to just say, yeah, we can just get rid of this social system. It will reemerge.

And the fact that we put so much effort into this social system, we put so much effort into pushing people, individuals, kids into these boxes, two boxes—I don't want to say anything about whether this means that this is not natural. I just want to say we should just stop with this system.

It's harming everyone. Not just trans people, not just nonbinary people. It's harming everyone. No one exactly fits the boys box or the girl's box. No one fits the woman box or the man box. And this is just causing suffering, we should get rid of this. And we shouldn't care whether in a world without gender there are some group level differences between humans with male or female genitalia. Just as we shouldn't care whether there are differences between people with brown and blue eyes or with brown and white skin.

BLAIR HODGES: And your book points out that a lot of people actually already experience the world this way. You surveyed several thousand cisgendered people, and that means people whose gender identity aligns with the sex of their body or the sex that they were assigned at birth. And you surveyed several thousand and found that most people report not feeling 100% like they're assigned gender anyway, that people experience the world and say, oh, you know, I don't, I don't tick all of the man boxes or I don't tick all of the woman boxes. That's not how the world is often experienced by anyone.

DAPHNA JOEL: Most people have both feminine and masculine characteristics. What we did is go to core gender identity, ask people, you know, how much do you feel like a woman? How much do you feel like a man? And usually these questions are studied only in people that do not fit the normative—the normative with, what do you call them?

BLAIR HODGES: With quotation marks around the word.

DAPHNA JOEL: Yeah, with quotation marks. And what we did is actually, we asked cisgender individuals and we were surprised that many, not most, but many cisgender individuals reported sometimes feeling also as the other gender or as no gender. And again, the binary framework assumes that if you were born male, you will grow up to feel as a boy, become a man, be sexually attracted to women, and similarly, if you were, you know, if you were born female.

But usually people do not study this, do not ask whether this is indeed the case. So they assume this to be the case for the “normative”—again in quotation marks—population or individuals. And they study only individuals that deviate from this assumed normativity. When you actually study the normative population, you find out that they are not as normative as you would expect. And they experience many what we could call queer or trans experiences.

 

Things We Can Do – 56:02

 

BLAIR HODGES: What do you suggest that parents do, or aunts or uncles or people that interact with our kids? What are some things we can do to, to reach toward this world where gender doesn't determine everything, or that we don't have these boxes to squeeze everybody into? What are some practical things people can do?

DAPHNA JOEL: So one thing is to when you treat others a certain way—could be your kids, could be other people—try in your head to switch the sex. So ask yourself, if this person was a man, would I be treating him or her the same way? If this kid was a girl, would I be treating this kid the same way?

And if the answer is no, then you know you are gender biased and maybe you want to change how you treat this person. So this is on the very individual level. When you have kids, you know, just give them and expose them to many activities, toys, et cetera, of course, without labeling them as appropriate to boys or girls.

But this is not enough because even if you raise your kids in a gender-neutral way, they are exposed to the world and the world is not gender neutral. So they go out and they see that there are differences and people treat them differently and they need to know about this. So I suggest to immunize our kids against this instead of denying the existence of the gender system.

So my kids, for example, growing up, they could say, you know, “Hey, mom, see this toy store? So funny that they colored one half of the store in blue and the other half in pink,” you know, and we could discuss what this means and how it affects their ability to choose from the pink or the blue sections of the store and why this is actually, you know, a pity because this restricts the ability of kids to just choose whatever they want.

So I try to teach them that people—some people, not all people, I don't, but other people—do believe that boys and girls are different, do different things. But you yourself, you know that this is not true. And this helps them be true to themselves or know who they are and what they like, even when they face other opinions or stereotypes from the outside.

So one of my kids really loved soccer, and he was playing and was on a team, et cetera. And he also really loved playing the piano. So he was also learning how to play the piano. And he came one day, they were coming back from a game and reported on a discussion that they had on the bus with other kids saying, you know, talking about kids who love soccer, they don't love, they don't play the piano. And I don't know if he said something to them, but he came to me and he said, you know, “I was really feeling sorry for these kids because, you know, obviously you can, you know, love football or love soccer and love playing the piano, but they don't think so, and they miss this thing that I love so much, and they are not able to experience this.”

So I think this is important. And it's not important whether he told them or didn't tell them. You don't have, of course, to send your kids to do these wars. But it's important that he could say, you know, I love playing the piano and I have soccer, and there is nothing wrong with this.

BLAIR HODGES: Right. And they're aware that this is a dynamic that exists in the world and that it will be something they kind of have to go uphill with right now. I think being aware of that and letting your kids know that you're aware of it and talking about it with them, that's a really important point that we can't Just pretend we live in this perfect world and treat our kids that way and not expect that external pressures won't have an effect.

Being involved with them and talking through it with them is great, it's really helpful advice.

DAPHNA JOEL: Yeah. Because I think if we deny this, if we just said, you know, boys and girls are the same and then they go out of the world. And let's say, you know, I have three boys, most of my examples are with boys, and two of them really liked pink and they would have pink things.

But going out to the world just thinking that everyone thinks that pink is okay for boys, and then maybe being ridiculed by other kids, this could be a very aversive experience. And it could also mean that they would not trust me anymore because I had said there was no problem. But there is a problem.

BLAIR HODGES: Yeah, right.

DAPHNA JOEL: It's a problem from the wrong reasons.

And I remember one time, one of my kids, they bought this kind of pink shirt for school. And then the next morning he told me, you know, mom, I really love this color, but I just don't feel like going to school and explaining to all the other kids that it's okay for boys to love pink.

And I told him, you know, this is perfectly fine. It's only important that you know that you love pink. You don't have to, you know, you choose your battles and you don't have to do this now.

BLAIR HODGES: That's Daphna Joel. She's a professor of psychology and neuroscience at Tel Aviv University and one of today's revolutionary specialists on sex, brains, and gender. We're talking about the book Gender Mosaic: Beyond the Myth of the Male and Female Brain.

 

Regrets, Challenges, & Surprises – 01:01:10

 

BLAIR HODGES: All right, Daphna, let's close with a segment called Regrets, Challenges, & Surprises.

This is an opportunity for you to reflect on what it was like to make this book. You can speak to one, two, or all three: Something you would change about the book now that it's out, something that was the hardest challenge about putting this book together, or something that surprised you and changed your view.

And in this case, I think you probably had done a lot of the research ahead of time. So I can't imagine much of the surprise happened in creating the book. Probably more as you were researching.

DAPHNA JOEL: So my dream for the book was to have a very short book that you can read within an hour and that would affect the way you think about sex, brains, and gender. Because I knew from my students—and by now I have hundreds of students—that the course in which I teach these things really affects their lives.

And I wanted to have a very short and simple book, but publishers wouldn’t accept a very short book that you can read within an hour and they wanted to have it longer still. It's a very short book compared to what's out there, but it's longer than what I wanted. So that is my regret, and I don't know if I could do it otherwise.

But now, it's more popular to have very short books. I think Amazon or whatever, some of the publishers do this. So my regret and my wish is maybe to have another edition which is much shorter, really having all these very, very crucial chapters that people can easily read and have a new way of thinking about these issues.

BLAIR HODGES: That's interesting because you're right. I mean, it’s still a very short book. I found it to be very well written. It's kind of a breezy read especially for getting into such scientific ideas. But I think you're right. You know, we're living in a time when like a TikTok video might be the place where somebody gets all their information about, about the gender mosaic. [laughs]

So it's a fast-paced world and people want their info in bite sized. So with that regret aside, maybe someday you'll go out and write the mini book that you dream of now.

DAPHNA JOEL: Yeah, maybe.

BLAIR HODGES: Also, before we go, I want to mention that people can check out the images that we talked about at your website and there's more at your website. Let people know a little bit about what you've got online that people can learn from.

DAPHNA JOEL: We recently launched a website in which people can do a very short survey and then see their own gender mosaic. So see how feminine and masculine they are on 40 different traits. And obviously, what's feminine and what's masculine differs between cultures. So after you finish and you see your own gender mosaic compared to a sample from the USA, you can choose another country—Japan, Israel, I don't know, Nigeria.

And you can see how your mosaic changes because obviously, I mean, you don't change the same answer. You don't have to redo the questionnaire. It's just how feminine or masculine you are compared to different cultures changes. So you can experience not only your gender mosaic, but also how it changes in different cultures.

And also there are many fun facts about differences between men and women across these different cultures.

BLAIR HODGES: Cool. What's the website?

DAPHNA JOEL: Gendermosaic.tau.ac.il.

BLAIR HODGES: Okay, great. I'll have a link to that in the show notes as well, so people can check that out. Thanks for joining us today, Daphna. Again, the book is Gender Mosaic: Beyond the Myth of the Male and Female Brain. And this was a great discussion. I really appreciate your time.

DAPHNA JOEL: Thank you very much.

 

Outro – 01:04:39

 

BLAIR HODGES: Thanks for listening to another episode of Relationscapes. If you enjoyed this one, I'll recommend a few fellow traveler episodes about gender roles. Try out Matthew Gutmann's episode, "Testosterone, Y Chromosomes, and Other Manly Excuses." If you're looking for more practical advice about how to break through gender stereotypes in relationships, there's Kate Mangino's episode, "Creating More Equal Partnerships."

And here's the part where I ask you for a favor. Please take a second rate and review Relationscapes in Apple Podcasts. The review doesn't have to be long, check out LJ's review, I just got this one, it just says "Love is Love," and it’s got a cute little heart emoji. Or my friend ChelseyG who said, "I always learn so much listening to such a smart and heartfelt show." Thank you ChelseyG!

Or you can use a few more words if you want, like my friend JessBrit7. She said, "These are the conversations we need to be having. Blair approaches things with warmth and knowledge that leads to fantastic interviews with a diverse group of guests." So kind, thank you Jess!

Now, dear listener, I invite you to go and do thou likewise. Rate and review Relationscapes. I have a goal. I want to get 100 ratings in Apple Podcasts by the end of 2025, and you can help me get there! Come on! I'm in the mid-80s. Get me across that finish line and help me reach my goal. You can also rate the show in Spotify or hop on TikTok because I’m doing some Relationscapes stuff there, too.

Mates of State provides our theme song. I'm your host Blair Hodges, a journalist in Salt Lake City, and I'll see you next time.