You're listening to Science Versus, the show where we pit fact against fad, I'm Wendy Zuckerman, and on today's show, The Female Brain. Is there really a difference between the brains of the sexes, and can it explain our behaviour? Researchers have been celebrating a breakthrough, and we've been discovering the secrets across the world. The idea of The Female Brain is that a lady's noggin is biologically different to a man's, so much so, that it makes women and men act and think differently.
But women are irrational, that's all that is to that, they're heads are full of coherence. You know, like in my fair lady. They're nothing but exasperating, irritating, basilating, calculating, agitating, mabbling and curating eggs. Often the differences between the sexes are attributed to evolution, which sounds like evidence-based science.
But it's not really. So in this theory, men invest less energy in reproduction than women. Yes, that is science. Men just need to pump out sperm while women create the egg, go through gestation, and then give the baby milk.
But the theory part begins, when people say that because of all of this stuff, differences in our brains evolved. So men became more horny because they just wanted to spread their seed while women became more nurturing, so they could take care of the baby. And that's all fine. But then, there's evidence-based science.
And a quick note, many of the studies looking into the brain differences of men and women don't ask about sexual preference, or really consider the gender spectrum at all. So, consider my privilege checked. And let's go back to the way we talked about boys and girls in the 1950s. Hey, hey, who's in kill?
What's cooking with you? And by the 1950s, I mean, we're pretty much still doing it today. Anyway. Men, you are better at map reading, and women, you are more verbally and emotionally intelligent.
Right? There have been a number of studies to show that women are actually better at verbal learning and memory tasks, whereas men tend to be better at spatial learning and memory tasks. This is Dr Rachel Hill, a neuroscientist at the Florian Institute of Neuroscience and Mental Health in Melbourne. However, there's an equal number of studies that show there are no sex differences.
And many of the studies that do find differences between the sexes find really small ones. Here's Professor Ian Hickey, he's the Executive Director of the Brain and Mind Research Institute at the University of Sydney. You end up with overall these very small group differences, things like emotional recognition tasks, which might call intuition, sensitivity, empathy. On the whole, you might find some better female performance on that.
What I hate is that things sense if you're unemotional and autistic when you're a boy. And if you're emotional and empathic, you're a girl. And I think that's where the distinction gets a bit silly. Or not one bit silly, gets really silly.
Still, Ian recognises that there are some minor sex differences. So, what could be causing them? Is it environmental, the way where hoped and prodded and told to behave? When I play with, I want to be a mommy.
You can play mommy right now, with ideals that... Or is this biological and seemingly hardwired? She drinks from her own bottle, just like a real baby. Well, that leads us to our next question.
What are the physical and biological differences between the male and female brain? Well, the male brain is, in fact, in volume slightly bigger than the female brain. The female brain has more grey matter, and the male brain has more white matter. This is Doctor Rachel Hill again.
And the white matter are these sort of tracks, they're sort of like roads or highways, that connect one area of the brain to the other. According to Rachel, having different amounts of grey and white matter really might matter, as it could mean that men and women perform tasks differently. So any sort of learning and memory task, it requires one part of the brain to talk to another part of the brain. So in terms of that white matter difference, definitely it's going to affect a male-female ability to be able to acquire a task and do it well.
She also says there are sex differences in the size of particular areas of the brain. Females tend to have a larger hippocampus, in comparison to males. The hippocampus plays an important role in our memory and our spatial awareness. But the fact that women might have bigger ones, does that mean we think differently to men?
We'll get to that a little later. Either way, Jennifer Raymond, an associate professor at Stanford University, is unconvinced by all these studies that seem to show sex differences in brains. The results have been highly variable. Even if you look just within male brains or just within female brains, there's a lot of variability.
So there's still some question about which of the differences between male and female brains that have been reported are real and which are not. What she means is that certain studies might report differences in the brains of the sexes, but then other studies come along and contradict those findings. So it's hard to say what these studies really mean. Professor Ian Higgy also has problems with the ways that many of these studies are conducted because they're ultimately taking a still snapshot of a working organ.
In truth, the brain is not a picture. It's a really active organ that is changing all the time. It's not a brain in the bottle. He's also unconvinced that structural differences seen on brain scans necessarily affect what we can do in real life.
Structure is not function. And it's really important. If I say to you, how do you open a jar? And you do it with your right hand and I do it with my left hand.
Oh, that's really different. So just because different areas of the brain might light up when a boy or a girl opened a jar or read a map. So long as we're both getting the job done. Does it matter?
Well, actually, not really, but you know, people go, oh, that's a right brain thing. That's a left brain thing. That's a boy brain thing. That's a girl brain.
Hang on a second. On the outcome function, it's exactly the same. Conclusion. There are some structural differences between the brains of men and women.
Men's brains are definitely larger on the average than the female brain. But that difference, which is probably the biggest difference that you see, is meaningless in terms of the functions. But what about other biological differences that might not show up on a brain scan, like hormones? Levels of testosterone and estrogen, they modify the brain during early development to be more male or more female.
Dr. Rachel Hill's work in mice has found clear differences in the way brains develop, depending on whether they get a testosterone or estrogen surge during adolescence. And she argues that early exposure to these different hormones can have an important impact on adult behaviour, while Ian Hickey agrees that the teenage brains of men and women are different. He says that by the time you're growing up and fully adult, afraid to say we're all rather the same.
That human adults, male and female, share so much in common. You know, they're essentially very similar in their cognitive capacities, their emotional capacities. That's not to say that men and women have the same levels of certain hormones. We don't.
But the picture of how it affects our brain and our behaviour is messy and unclear. A lot of people don't realise that estrogen and testosterone are both present in males and females. He's associate professor at Jennifer Raymond again. And that these can fluctuate quite a lot, the levels fluctuate over days and over years, and can be affected by things like experience.
So even simple things like your posture. If you sit in a lady-like fashion with your legs crossed and making yourself very small, versus in a big open posture like a big boss behind his desk with his legs up, that can affect your hormone levels. And you might have heard of oxytocin. That's the so-called cuddled chemical, releasing females during childbirth to promote bonding with her baby.
It's been used to argue that women are more nurturing than men because women get this oxytocin search. Well guess what? A boy's have oxytocin too. We got it.
And another thing. If we were to see real biological differences between men and women, whether that's hormonal differences or neural connections or brain structures, that doesn't actually mean that men and women are hardwired to be different. So the simple idea that's either innate or it's taught, the sort of nature versus nurture, is really so non-inseventy and so unhelpful. Sorry, I clearly let that music run too long.
Let's go back to Professor Ian Hickey. I'm not suggesting there are no differences. There are differences. In terms of understanding these things, where things are really out is not simplistic boy versus girl.
Because what you do in your environment is ultimately reflected in your brain. The more and more you do things in certain kinds of ways, the more of the brain will change to reflect that. So the activity changes the brain. Now couple that with information we have from psychologists showing that boys and girls are treated differently from birth.
Here's Dr Jennifer Raymond from Stanford again. After decades, if we can find differences in the brains of adult men versus women, well, it's likely that much of those differences have come from their different experiences. Rachel Hill acknowledges that there is an interaction between the environment and brain pictures, but she still believes there are differences between the sexes that matter to our behavior. I think my belief in these six differences comes from all of my animal work, where we can control all these outside variables.
We can keep animals' housing, exactly the same housing condition, look at them at exactly the same time point, and we do see very strong six differences. That sounds like a really strong claim. But Dr Rachel Hill is a scientist, and when she talks about differences, there's statistically significant differences. So in the real world, they can still be quite small.
The differences are very subtle. I mean, after all human, a male and female again perform far better than an ape, for example. So there is some scientific debate about what these small, six differences that we see in the brain might mean in the real world. But curiously, one area that might help us untangle this mess is mental illness.
Here's Professor Ian Hickey. Girls have an onset of more emotional disturbance in the teenage years, more reporting of anxiety and depression and changes in cognitive kind of structure, more getting stuck on things ruminating, getting preoccupied with certain kind of issues early in adolescence. On the other hand, boys tend to outnumber girls in the diagnosis of ADHD, autism spectrum disorders, and dyslexia. And this has sparked a lot of research into whether any biological sex differences might make women or men more susceptible to certain illnesses.
That's what Dr Rachel Hill thinks. She believes that minor sex differences might make men or women more vulnerable to a certain environmental factor. So if the brains of the sexes are formed to be more susceptible to certain illnesses, is it possible that they're also more susceptible to having certain behaviours, like given the exact same environment? Maybe females are more likely to be nurturing.
Ah, for example, boys and girls equally sensitive to the feedback defects of oxytocin, this breastfeeding and sociability hormone on the brain on development. There are some open questions here. To how does it all work to produce the particular thing? But it's not necessarily intrinsic.
Take girls, put them on their own, decrease their socialization, guess what? Those brain connections go away. Okay, so does the female brain stack up? Well, the structure of the male and female brain is a little bit different, but we don't know whether this has any impact on our lives.
And those hormones, which are fluctuating in men and women, are also unlikely to clearly explain our behaviour. Plus, when it comes to psychometric testing, all that spatial awareness and emotional intelligence, there seems to be minor differences, but again, how that plays out in the real world is pretty murky. So, all those stereotypes of hardwired, important differences between men and women, they're bunk. But are there subtle differences that might affect our behaviour?
That remains a matter of investigation. I think what will emerge as the lives of men and women have become more and more similar. So the developmental experiences have come more similar. The educational status of social status has become more similar.
What you'll find is much greater differences between individuals, but less and less of that explained by the difference in gender. So, when it comes to science versus the female brain, bad science, well, I think nil. Because all those brain pictures and evolutionary stories, they're very conflicting. And the female brain?
Why can't a woman? That's nil too. That's it for science versus, you should subscribe to us if you haven't already. You can use iTunes, SoundCloud or your favourite podcast app.
Next week we're tackling sugar. Where does the science end? And the fad begin. There's a raging debate about our all calories the same.
And the answer is in terms of weight. The answer is... Just a big thanks to Caitlin Sorey for her wonderful editorial advice and all of the comments from my family and friends, particularly my sister Debbie Zuckerman. Thank you for lending your amazing, non-sex specific brain.
I'm Wendy Zuckerman. Back to you next time.