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- [00:00]
A
Do you think that you could have published this book six years ago?
- [00:03]
B
I think that I could have, but it would have been a less wise move. I think it would have gone down a lot worse. Six years ago. Things have kind of cooled off a little bit, I think.
- [00:13]
A
Why is talking about sex differences so controversial?
- [00:16]
B
Well, it's a good question and I think that it's a few things. I mean, sometimes it surprises me because sometimes I think a lot of the differences that we're talking about, they're really quite modest differences. They are often differences in preferences rather than cognitive abilities. So they're kind of neutral as far as I'm concerned. And if anything, I think probably they put men in a worse light than women. So sometimes it surprises me. But I think really the main reason is our long history of sexism against women. And I think that we've got quite a long science as well, has a bit of a sordid history in terms of how we've spoken about women, especially in the 1800s. I've got a quote, one of my favorite quotes, one of my favourite examples of this is from scientist by the name of Gustave Le Bon. And he wrote that, sure, there are some women who are as intellectually accomplished as your typical man, but they're about as rare as a two headed gorilla. And so therefore we don't really need to think about them. So with stuff like that in our background, it's I guess not surprising that people are a little bit nervous about talking about evolved sex differences. A little bit worried that if we start doing that it's going to open the door to that kind of, that kind of sexism. I think they're wrong to worry about that. I think that really the science of sex differences has disproved those kind of ideas. And I think as well that we can treat men and women respectfully and humanely and treat them well, even if men and women are not identical on average on every single trainer.
- [01:50]
A
Yeah, I suppose the history of science is to sex difference is what the Nazi party is to behavioral genetics.
- [01:57]
B
Right, right, exactly. Yeah, yeah. And I do think that science is the solution to the early sexism rather than a continuation of it.
- [02:06]
A
Yeah, that's a great way to put it. All right. Why is it important to study sex differences then? Why should anybody care?
- [02:12]
B
I think lots of reasons. The main reason for me is I think it's just deeply, deeply fascinating. I just think it's the best.
- [02:19]
A
It's the best. Dude, me and you fell in love with the same book, the Moral Animal by Rory. Right. It changed my life.
- [02:24]
B
Yeah, likewise. It changed my life. It shaped the rest of my career. Just. I think it's deeply fascinating. And yeah, I remember when I read that book, that's when I fell in love with. Fell in love with evolutionary psychology, and in particular fell in love with the evolutionary psychology of sex differences. And I got the same feeling that I did when I was a kid and I first understood how the phases of the moon work. And everything just clicked into place. Suddenly the whole thing made sense.
- [02:51]
A
That is why it looks that way. That is why people that way.
- [02:56]
B
Exactly, exactly. It all made sense. It was clear that it was true. And. Yeah, just sort of instant insight and.
- [03:04]
A
Yeah, interesting. Even as you're saying it, I can hear this sort of critic preparedness inside of my mind going, why would you, when you read a book, why would both of us, when we read a book, be so enamored by sex differences? That must be because you are secretly a sexist who is looking to try and keep people in their place and not ever have any program. You know what I mean? Like, the conversation around this has become so tarnished and accusatory. Yes, yes. Yeah. You can't have an interest in something which is fundamental and fascinating and really important. Right. So that you don't try. And people aren't trying to fight against something so that we don't fully account for and understand why behavior unfolds in particular ways that can allow us to have a better society, a society that's got outcomes that's more close to what we want. Fascinating.
- [03:58]
B
Yeah, it is. Yeah. So I do. I agree with that. And I think. Yeah, sorry, I just. I just went blank. What was I going to say about it?
- [04:10]
A
Just why is it important to study sex?
- [04:12]
B
Why is it important? Yeah, so that is. That points at another reason. So one big reason why it's important is just the fact that it's fascinating. But I think also that, like you say, it is important in terms of steering society in positive directions and understanding ourselves, understanding interactions between men and women in terms of trying to keep people in their place and the like. That's certainly not the philosophy that I come away with from having studied all this over the years. Instead of my basic philosophy, I think I can summarize in just four words. And those words would be let people be themselves. So if they fit with traditional gender roles and expectations, that's great, but if they don't, that's great as well. It doesn't matter. The fact that something has evolutionary origin doesn't necessarily mean that it's good. It doesn't necessarily mean it's bad either. I think that it's morally neutral and that it's up to us to decide whether it's good or bad or somewhere in between.
- [05:08]
A
I think that's a big fear that people have, that by looking at the evolutionary explanation for why certain traits show up the way that they do, why certain differences occur the way that they do, it sounds like you're excusing away that behavior.
- [05:21]
B
Indeed. I think a lot of people do worry that that's the case and that people will assume that it's the case.
- [05:26]
A
It's naturalistic fallacying your way through all of the bad behavior of men or all of the worst behavior of women or the most repressive ideas that we have for how people should behave.
- [05:36]
B
Yeah, yeah. And I don't think that it does justify any particular behavior, but I do think it's right to worry that people might assume that it does, falsely assume that it does. So I do think when we discuss these issues, that we should take into account the concerns that people have about this whole topic of sex differences and we should discuss them carefully. And we should always emphasize that most of the gaps are not huge, most of the psychological sex differences are not huge, that there's a huge amount of variation within both sexes, tons of overlap between the sexes, and also that there's no normative implications of these generalizations, so no sense of because something is evolved, because something is natural, that that therefore means that it's good or even permissible. Again, it's up to us to decide that.
- [06:22]
A
Right? To say that the differences are modest at best, but when you start to stack them on top of each other, you end up with huge. You basically end up with two completely separate Venn diagrams. Right. It's not just preference for violence and risk taking and parental investment and da da da da. It's when you put all of them together, you do have two very different groups of people.
- [06:44]
B
Yeah. Those are called multivariate sex differences when you sort of cluster the differences. I think that while that's statistically true, I think we need to be a little bit wary about the concept of multivariate sex differences just because often we are thinking about single traits. So often we're thinking about sex differences in parenting, sex differences in sexual interests and aggression, risk taking and so on. But also, if you were to divide up, take a group of people, divide them into two based on a flip of a coin, they're not going to be identical on every trait, there's going to be small differences between them. But then if you add up all those traits, you could just as well stack up the differences between these two randomly chosen groups of people, stack up the differences, and you'd find that they equally massively discrepant from each other based on the multivariate statistical approach. So I think that you need to be wary about exaggerating the magnitude of human sex differences based on that statistical approach, because you could just as well exaggerate the sex differences between New Zealanders and Australians or the British and the French, or like I say to randomly
- [07:54]
A
British and the French do that. Enough already.
- [07:55]
B
All right.
- [07:56]
A
There's been, the last few years, there's been a huge debate about what sex actually is.
- [08:00]
B
Yeah.
- [08:01]
A
What's the definition that you land on?
- [08:03]
B
Well, there are a few definitions. The one that I land on is the traditional scientific definition via which sex is defined in terms of gamete size. So in the vast majority of sexually reproducing species, you have two different gamete sizes, and the small gametes are called sperm. The larger gametes are called eggs.
- [08:24]
A
Is that across the board?
- [08:25]
B
That is across the board.
- [08:26]
A
No way. So almost every sexually reproducing male.
- [08:33]
B
Yes. Produces sperm.
- [08:34]
A
Yes.
- [08:35]
B
And sexually reproducing female produces eggs.
- [08:37]
A
I know this might be like the most face palm thing. I'm like, wow, I didn't know that those are the only two currencies at play.
- [08:44]
B
I mean, it seems like. So in biology, it's not like math. Right. So in biology, there are very rarely generalizations that apply to every single species. This is one of them. But the reason is that it's a definitional truth. So we define males as the ones that produce the smaller gametes. The empirical truth that in principle could have gone another way is the fact that in the vast majority of species, you have. Where the gametes are not identical, you only have two different types and one is bigger and one is smaller. And that's true right across, you know, all species, except the minority where you. You have. So that's called anisogamy, where you have two different sizes and you have a few isogamous sexually reproducing species, but the vast majority anisogamous.
- [09:29]
A
Can you. What's an isogamous sexually reproducing spirit? What are some examples of them?
- [09:35]
B
There are some very, I think no animals and no plants, but I think maybe some simple bacteria and things like that. And I think that that would have been the starting position. So we all evolved from species that originally were Isogamous, first of all, sexual reproduction would have evolved then and they would have been isogamous, they would have produced the same gametes and mixed them. But then that's evolutionarily unstable and that tends to fall apart into smaller and larger gametes.
- [10:03]
A
Why is it unstable?
- [10:04]
B
Because when you, when you have same size gametes, this selection for any trait that will increase the chances of being one of the gamete, of producing gametes that are going to produce offspring that survive. So that creates a selection pressure for maybe loading up your gametes with some extra supplies to help them survive. So some gametes get a little bit bigger because of that. But as soon as they get big enough, the larger gametes, you have a selection for smaller gametes that seek out the larger gametes and kind of ride on their coattails. And so and you get this, it pushes them apart.
- [10:40]
A
And it's actually from a sexual survival or a gamete survival perspective.
- [10:47]
B
Yep.
- [10:47]
A
It's the gray area in the middle of the barbell is where you go to die. And the black and the white on either end are actually the ones that are most effective.
- [10:55]
B
Exactly right. Because the ones in the middle, they're not big enough. They don't survive as well as the bigger ones that pack a picnic for their offspring.
- [11:02]
A
But they're also strict motility, mobility by the smaller ones.
- [11:06]
B
Exactly. And just numbers, you know. So like if you are producing small gametes, you can produce many more. So individuals that produce the medium sized gametes, they don't survive as well, plus they don't produce as many.
- [11:15]
A
I remember what the stat is. There's some stat around. Jerry, can you look at chatgpt? How many sperm are produced per day? Human sperm versus human eggs. It's, it's such a hilariously big difference.
- [11:28]
B
Yeah.
- [11:29]
A
Okay. So broadly across the animal kingdom, in almost every single sexually reproducing species, there's a binary.
- [11:38]
B
Yep.
- [11:39]
A
There's a sex binary.
- [11:40]
B
There's a sex binary. Yeah. There's also a ton of variation in terms of the phenotypic characteristics within each of those sexes. But yeah, there is a sex binary, you know, and you do get intersex individuals.
- [11:52]
A
Yeah. What about the challenges to this? We have hermaphrodites with insect variation, intersex conditions. Does that disprove this?
- [12:01]
B
It doesn't. So I guess the easiest one is the within sex variation. There is tons of it. So the variation in terms of levels of masculinity, levels of femininity, just size dimorphism versus size monomorphism where they're about the same size, but nonetheless, they are all either producing sperm or eggs. The vast majority. Within each. Within each group.
- [12:24]
A
You've seen that image, right? Of the bell curve graph. And you say, on average, something, something. And then somebody says, well, I know a person who is actually more that than the other group. I know a woman who's 6ft 7 and she's actually taller than most men. Most men on average are taller than women, while my friend's 6 foot 2. You go, right, okay, but that doesn't necessarily disprove the way the generalization. Exactly. The fact that the generalization's there, and even more so the fact that the gamete size is definitional, as you say. Oh, here we go. I don't even know what that number is. Is that sperm? Is that a billion sperm?
- [13:03]
B
Hundred to 300 million sperm per day produced by healthy animals.
- [13:07]
A
No, no, no, no, no. I want this globally. Total global sperm production. 200 quadrillion eggs released. 70 million. Step it up, ladies. That's what I think. Fucking lagging behind. We need to up the egg production. That's what I say. So much of the debate falls around nature versus nurture. So much of it. How do you even begin to start to separate this out, right? Almost no women have grown up in a society that hasn't had other women with the expectations of women. And almost no men have grown up in society that doesn't have the expectations of men. How do we know that all of the sex differences aren't just socialization?
- [13:46]
B
It's a good question. And I think the first thing I want to say about that is that evolutionary psychologists don't deny that socialization has a very important impact on the nature of sex differences in any given culture. We know that it does have a big impact because we know that sex differences, their size and the exact details of them, many of them vary across cultures and vary across times. But in terms of how we know that it's not just socialization, there are various lines of evidence that point in that direction. None of them are perfect. None of them by themselves seal the deal. But the reason I'm persuaded is that they all point in when you get a sex difference, and they all point in the same direction. That just makes a very strong case. I think that it's not just due to socialization. And in the book, I lay out six different lines of evidence for an innate contribution to any given difference. See if I can remember the name. So the first one is that a lot of sex differences, they appear very, very early in the lifespan so early, in fact, that even though it's conceivable that it could be a result of socialization, it just seems less plausible than that. There's actually also an innate push. So the aggression sex difference and the risk taking sex difference, both of those appear basically as soon as kids are mature enough that they can move around the place and are capable of risk taking, capable of aggressing, you get that sex difference like immediately. And a good example of that is that right from the get go, right from early toddlerhood, more boys than girls end up in the ER from doing more risk taking. And also if it appears at puberty as well, like a lot of sex differences, innate sex differences with an innate basis, they.
- [15:29]
A
What do you mean when you say innate?
- [15:31]
B
Unlearned. Right, unlearned. So there's an innate contribution. An unlearned contribution. And where that's the case, often you find that the sex difference, you may get it to some degree early in the lifespan, but then post puberty it just skyrockets and expands.
- [15:46]
A
Right, okay. Which would suggest that there is a biological basis. Or else why would this big change occur when puberty happens?
- [15:53]
B
Exactly. And do so right across cultures?
- [15:56]
A
Would the suggestion from social roles socialization theorists be that while during puberty culture ramps up its pressure on people, there's a greater expectation on young men and women to change their behavior?
- [16:13]
B
That would be the way that you would have to. You'd have to try to explain it, Something like that.
- [16:17]
A
Yeah, I think they're more absorbent, they're more, yeah.
- [16:22]
B
More plastic at that age perhaps. Yeah, you could do that as well. And that's sort of implying an innate contribution to the plasticity, I guess, but yeah, not to the specific sex difference. The reason I don't buy that though is that most cultures actually try to suppress male aggression. For instance, in every culture, male aggression, post puberty, young male aggression, violence, risk taking, homicide is a big problem that the society has to deal with. And so usually they're trying to clamp down on it rather than trying to encourage it. And nonetheless you get this increase in aggression. That's true. And actually this is the second line of evidence is that often these sex differences appear despite culture rather than because of culture. Culture's trying to push down aggression right from early on. Parents, teachers, early on they actually tell off boys for aggression more than they tell off girls for aggression. Not because they disapprove of girls aggression, but just simply because boys are more aggressive. So they have more cause to do
- [17:24]
A
it, I think Fmris of developing fetuses in the womb can detect sex differences at three months.
- [17:33]
B
They can, I think, I think even younger in some cases as well.
- [17:37]
A
These boys and girls, these tiny minus six month year olds, are they learning that their brains develop differently?
- [17:48]
B
Yeah, they've been socialized to develop different brain strengths inside of the womb.
- [17:51]
A
Yeah, yeah.
- [17:52]
B
It's not plausible. So early development, early development appearing despite culture rather than because of culture.
- [17:58]
A
Yep.
- [17:59]
B
Another one is that they persist often for a long time. So for instance, sex differences and mate preferences were really consistent Right. Throughout the entirety of the 20th century in the U.S. sex differences in career preferences as well, or career related interests. They were evident from the early 1900s when people first started measuring them and then they just stayed the same. So the average difference, the fact that men for instance, on average more interested in things and things related jobs, whereas women on average are more interested in people and people related jobs, that was the case right throughout the 20th century, despite the fact that there was quite a strong social. There was a lot of social pressure to try to get more women into traditionally male roles and it persisted nonetheless.
- [18:47]
A
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- [19:56]
B
Well, I think a Lot of them do. You know, it's tricky. So I guess we know because of cross cultural differences in male typical behavior, female typical behavior, and the size of the differences, that something is making the difference. But it is actually quite tricky to figure out what, what it is that's making the difference because we know, for instance, that, okay, so like a popular explanation is that it's how parents treat their kids. And that seems incredibly plausible that it's going to have an effect. There are a few reasons to think maybe that it has less effect than we might think. So one is that a lot of research in the west finds that parents don't particularly treat their sons and daughters differently in some important ways. Like they're equally likely to encourage them to be successful, equally likely to encourage them to be independent. Another line of evidence against parents having a big role is what's called the second law, behavioral genetics. And that's the finding that when two people, okay, so take identical twins. Two identical twins, they grow up in the same home, you'd expect them to be more similar to each other than two identical twins who are separated at birth and reared apart. And in childhood they often are quite a bit more similar than you would expect by chance. By adulthood though, they're often not much more similar at all, and in some cases no more similar than they would be if they had grown up apart. Which is a surprising finding, but a really consistent finding. And it suggests maybe that parental treatment affects individuals less than we might think that they would. Which kind of pulls out the rug a little bit from the idea that parents are having a huge impact on sex differences.
- [21:37]
A
Specifically, what about the gender equality paradox?
- [21:40]
B
Well, that undermines another kind of socio cultural explanation, which is the idea that the sex differences that we see are products of the social roles of a culture and shaped by just social roles theory. Yeah, social roles theory, exactly. And patriarchy theory, the idea that it's due to patriarchy, that as well is undermined by the gender equality paradox. Because both of those theories would predict that in more patriarchal societies, societies that are more patriarchal societies that have stricter gender roles, you'd expect that predict that the sex differences would be bigger in those societies than they are in less patriarchal societies and ones that have less strict social roles.
- [22:26]
A
What would be some examples of how that would play out if that was true?
- [22:30]
B
Basically, any sex difference you care to name, aggression, sex difference, sex differences in masculinity versus femininity, all of those should be bigger. Sex differences in career related preferences, they should be bigger as well. And the gender equality paradox is the deeply counterintuitive finding and incredibly fascinating finding that often it goes the other way. Seems to go the other way that actually in more gender equal societies, societies that are less strict in terms of their gender roles and societies that are less patriarchal, you actually find larger sex differences, often rather than smaller ones.
- [23:02]
A
Which is in the direction that you would predict as well.
- [23:06]
B
Yeah. So opposite to the direction you predict if social role theory.
- [23:10]
A
Right. Yes. Yes, in the direction you would predict if you were taking an evolutionary perspective, I would imagine.
- [23:14]
B
Well, actually, you know, taking an evolutionary perspective, I. I didn't originally predict that. I thought that in more patriarchal societies, even given that there's an innate push towards certain sex differences, I still thought that patriarchy and stricter sex roles would pry the sexes apart even more.
- [23:30]
A
Right.
- [23:30]
B
So I was actually very surprised that it doesn't. And that does the reverse as the real surprise.
- [23:35]
A
What are the rebuttals that sociocultural explainers have for the gender equality paradox?
- [23:44]
B
There are a few. One is that people in more patriarchal societies, they tend to the men and women have little to do with each other. And so they have a more sort of exaggerated picture of the other sex. And so when they fill out personality inventories, for instance, they're comparing themselves with other men if they're men, or other women if they're women. And they therefore see themselves as being more similar to the average for their comparison group. But the comparison group is just their sense.
- [24:14]
A
They're so siloed off in these patriarchal societies that they don't know what the fuck the other side's doing.
- [24:19]
B
Exactly. Yes, it is. It is.
- [24:23]
A
You're just in a bunker so much that you don't know what's going on.
- [24:26]
B
Exactly.
- [24:27]
A
Plausible.
- [24:29]
B
It does. But there's also plausible rebuttal to that rebuttal, which is.
- [24:33]
A
I fucking love it. It's so good. This is my shit. This is my shit.
- [24:39]
B
So it doesn't just apply to self report things like personality. You also find that for some cognitive abilities, I think spatial ability, for instance. You find it.
- [24:47]
A
Yeah.
- [24:50]
B
You find that as well for physical traits like height.
- [24:53]
A
Are you saying that in more gender equal societies, boys get even better? Better at throwing.
- [24:59]
B
I don't know if that is actually the case, but that. That would be one of the. There's research on that. I'm not sure if there is actually cross cultural research throwing.
- [25:05]
A
My favorite one. Dude.
- [25:06]
B
Huge.
- [25:07]
A
It's one of my absolute favorites. Did you ever look at that study where. So the Difference in throwing velocity, accuracy is a pretty big sex difference. But one of the appropriate pushbacks was, well, men's shoulders articulate differently. The length of the forearm means that you've got more leverage, et cetera, et cetera. I think the sex difference at eight years old in throwing velocity and accuracy is basically the same as adult men and women being able to detect adult women and men just by their face. Right? It's 90%. Yeah, it's a huge, huge, huge difference. So there was this, my favorite study on this was in order to negate the articulation argument, the issues of sort of biomechanics. They got a tennis ball serving machine and fired tennis balls at students and got the boys and the girls to see if they could get out of the way. And I don't think any of the males were hitting. And I think that this is before you wouldn't have been able to get this past an ethics board. But yeah, just the sort of spatial awareness that spatial rotationy stuff is, the sex differences is pretty large. And apparently maybe in a more gender equal society, even more women would be hit by the tennis balls.
- [26:23]
B
Well, that's possible, yeah. So the gender equality paradox, it doesn't apply to every trait. So it might not necessarily be bad, but. Yeah, but you are right. I think that was probably a 70, I think it was a 70s study. I'm not sure you could do that. In fact, you couldn't do that. You couldn't aim projectiles at participants in studies anymore, sadly.
- [26:39]
A
What's the largest sex difference between men and women?
- [26:44]
B
Well, the largest ones are physical differences. Physical sex differences. So the very largest are sex differences in reproductive anatomy where basically all males have penises, all females have vaginas and so on. But other physical sex differences are also very, very large. So the sex difference in upper body strength is huge and there's very little overlap, close to no overlap for that one. The sex difference in voice pitch is another very, very large one as well. That's huge. Which is quite interesting because the voice pitch sex difference in other apes is not as big. It's nowhere near as big. And that's even the case for other species that are much more dimorphic than us in terms of size, like gorillas and orangutans. So it's a bit of a puzzle. I'm not quite sure why that's the case. When it comes to psychological sex differences. The vast majority of them are much more modest. But there's one that stands out as being, as being almost as big as Some of these physical ones. And I always ask people if they can guess what it is. I think last time I was on your show, actually, I asked you if you could guess and you didn't. But, I mean, no one does.
- [27:54]
A
I've read the book now.
- [27:55]
B
You've read the book now. So you got a head start on
- [27:58]
A
can you guess what it would be? Jared, the. The single biggest psychological sex difference between men and women is aggression.
- [28:07]
B
It's not aggression. I'll give you a clue, and that's that. It is. It's related to reproduction pretty closely. What was that version? Well, actually, that is a big sex
- [28:17]
A
difference, but not as big as this one. Speak for yourself, too.
- [28:23]
B
It's the sex difference in which sex each sex is primarily attracted to. So men, most. The vast majority of men are primarily attracted to women. The vast majority of women primarily attracted to men. And when I say it, it's obvious, right? It's just obvious that it's a big sex difference. But it's curious, people don't think of it. Even scientists often don't think about it. I've read a bunch of papers that summarize evolved sex differences, and they don't tend to mention that one. They often neglect to mention that. That very, very large one. But also that one that has quite a clear evolutionary rationale. Very interesting.
- [28:57]
A
Because if that wasn't the case, we wouldn't be here.
- [29:00]
B
Exactly.
- [29:00]
A
Literally. Literally.
- [29:01]
B
We literally wouldn't be here.
- [29:03]
A
Okay, so what are the biggest sex differences? Let's get down to some brass fucking tacks. What are the biggest sex differences when it comes to sex?
- [29:09]
B
When it comes to sex, one of the largest ones is the sex difference and interest in casual sex and sexual variety. And so basically, sociosexuality. The trait of sociosexuality, no strings attached to sex. Do I need to mention which direction it is? People might be aware of it.
- [29:29]
A
Someone can intuit it, I guess.
- [29:31]
B
Yeah. So men on average score higher. However you measure that trait. They score higher than women on that trait. The differences there maybe, though, are not as huge as people sometimes assume. We're looking usually at an effect size of about Cohen's D equals 1. So what that means is there's about one standard deviation between the average for men and the average for women. So, yeah, between 0.8 and 1. And that is pretty big. That is big for a human sex difference. But there is still quite a bit of overlap. So there are plenty of women who have a higher sociosexuality than plenty of men, I guess. An intuitive way to put it, a way to make it intuitive would be to say if you imagine plucking two people at random, one man and one woman, with effect size of 0.8 or 1, probably 2/3 to 70% of the time, the man will score higher than the woman on that trait. So that is a majority. It's not an overwhelming majority, though. In a significant minority of cases, you'd find that actually the woman scores higher than the man.
- [30:37]
A
Why?
- [30:38]
B
Why is that sex difference? That is getting right into the central question of why there are any sex differences.
- [30:45]
A
I suppose we probably need to talk about the evolution of sex differences, why they exist in the first place.
- [30:50]
B
Yeah, so we should jump to that. Just as an aside, though, we mentioned three of the six lines of evidence for innateness. Do we want to jump back and do the other three and then maybe get into the sort of thing. So what do we. So we had the developmental sex differences, we had the resistance to cultural pressure, we had the persistence across time. So another one is hormonal correlates of sex differences. And in particular you find associations between prenatal hormonal exposure and traits found later in life. So higher levels of testosterone in the womb, for instance, are associated with high levels of aggression, later, high levels of risk taking, lower levels of parental inclinations and so on.
- [31:43]
A
And that's regardless of sex.
- [31:45]
B
That is, regardless of sex. Yeah. So you can look at within sex differences as well. And yeah, so one actually very strong line of evidence for that claim is the fact that women who, when they're in the womb are exposed to very, very high levels of prenatal testosterone due to having a condition called congenital adrenal hyperplasia, or cah. They as girls and then as women, they exhibit a lot of male typical traits.
- [32:16]
A
Less interested in playing with dolls.
- [32:18]
B
Exactly. Yeah. Less interested in getting married and having kids. More interested in things, related professions as well. So that's pretty interesting.
- [32:26]
A
Does make them more likely to be bisexual or lesbian.
- [32:28]
B
Yeah, yeah, it does. It makes them more likely to be interested in other women sexually as well, either as bisexuals or as lesbians. Yeah. So like, a wide range of traits seem to be influenced by sex.
- [32:39]
A
So the fourth one is correlates with hormones.
- [32:42]
B
Yep. The fifth one is cross cultural universality. So most of the key sex differences that we've been discussing so far, they are found either in every culture or in the vast majority. And if it were all just down to culture, you wouldn't expect that. You'd expect there to be more variation across cultures. In what we found. But you don't, you know, you just always have. Like in every culture, you find that men are more aggressive than women, and you find at the extreme of aggression, in particular, the differences are particularly big. And you find that the vast majority of homicides are perpetrated by guys in every single nation for which we had data. Greater risk taking, more accidental fatalities among men than women. Women across cultures are more involved in parental care, and so on and so on. And then last but not least, and maybe this is the one I find most plausible on its own, is the fact that a lot of these sex differences, you find them as well in other species. You don't find them in all other species, but importantly, you find them in species that were subject to the same evolutionary selection pressures as ourselves. And actually, the selection pressures of question bring us to the ultimate roots of evolved sex differences. So basically, most sex differences emerge from the sex difference and what I like to call the maximum offspring number that male animals versus female animals can produce. And in most species, the males potentially can produce more offspring than females. That average number of offspring has to be the same. At least in species where you have a similar sex ratio, the average has to be the same. But the variance in the number of offspring produced can be greater in one sex than the other, and it's usually greater in males.
- [34:32]
A
Why does the average need to be the same if the variance can be different?
- [34:35]
B
Because it takes two to tango. And so every offspring that's produced is produced by one male and one female in most species.
- [34:44]
A
But if you can have one male servicing 20 females, why not have a 20 to 1 ratio?
- [34:50]
B
Well, that'd be a 20 to 1 ratio in terms of the number of parents. But the average number for each sex would be the same because you got the one male with 20 times more than any female, and then nine, and that's a really high number. But then the other 19 bachelors who never get to have kids, that brings the average for males down. And then it's the same for all the females. So you average out across all of them and the average is the same.
- [35:14]
A
I get that. I. Sure, maybe I'm being stupid. Why is it not the case? Given that men, given that males are able to produce more children than women can than females can, why is it not the case that there is a bias toward fewer males in the animal kingdom?
- [35:33]
B
Right, right. That's a great question. And that is one of the sort of early mysteries of evolutionary biology. And if it were for the. If selection acted for the Good of the group. That is what we'd find. We'd find if you only need one male for every 20 females and selection were for the good of the group, you get that. Because if you have 20 of each, then the other 19 are surplus and they're using up easy resources and they're competing with each other and fighting with each other. It's not good for the species as a whole. But selection favors what's good for the individual. And for the individual, I could be the one. You could be the one. Exactly. And the average is the same. So I guess useful to think about, think about it from the parents point of view, like, is it better to have sons or daughters? And if there were 20 females for every one male, it'd be much better to have sons because each son is going to just have. There's going to be tons of females. And so that would mean that selection would slowly favor an increase in the number of sons.
- [36:35]
A
Motherfucker, you can't beat evolution.
- [36:37]
B
Exactly. And the reverse, if there's 20 males and only for every female, then it would be better for parents to produce daughters because then they get the cream of the crop. And 20 males, probably they're going to have a low number. So it's better to have daughters. So the equilibrium point is 50.
- [36:53]
A
50, yeah. Obviously as well, there's survival and not just reproduction. We're not living in this perfect, hermetically sealed, safe environment. Males do other things than just reproduce, regardless of whether they can do 20 to 1 or not.
- [37:07]
B
Indeed.
- [37:08]
A
Yeah. Getting food, helping to protect, getting rid of other tribes, et cetera, et cetera.
- [37:15]
B
Yeah, yeah, exactly. And you know, there are plenty of species where the male, his role in reproduction is just the reproductive act and then he's off looking for other females. But we're not one of those species. I mean, that does happen occasionally. There's occasional male that will do that, but generally we're quite involved in childcare. Yeah. So, okay, so the big difference there is you get this difference in the variant. Some males can have tons of offspring and they can have many more offspring than any female can. Where that's the case, though, there's going to be some males that had no offspring or maybe a few or none. And where that's the case, you get strong selection on the males to be one of the lucky few males that has many offspring, rather than one of the few that has none, one of the many that has none. And so that selects for traits like greater aggression within sex, aggression to try to beat up other Males for either directly for females or for the territories. The status or the resources that are necessary to attract female attention. A tendency to show off. A tendency to grow a great big tail. If you're a peacock, you might want to try that. Grow a great big flashy tail to seduce the peahens. Or just a tendency to seek multiple mates and seek no strings attached sex basically. So that's the answer to your earlier question is that that's why you have selection for like stronger selection on males than females for an interest in multiple partners and sex without commitment kind of thing.
- [38:48]
A
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- [39:49]
B
That is a major contributor and the reason is that so this variance sex difference is mainly a result of sex differences and parental investment. So the reason that some males can have many many more offspring than any female in a lot of species is that females invest more in the young. So in mammals, for instance, to produce any one offspring, a female has to have a long pregnancy, has to give birth to the young, and then has to nurse the young for a while. Whereas a male, to produce an offspring just in principle only needs to engage in one sex act so he can mate with multiple females and have tons of offspring because he invests potentially little in any given offspring. Whereas the females, on the other hand, they invest a lot in each offspring. That lowers the ceiling for the number of offspring they can produce.
- [40:41]
A
Therefore you have to be choosier.
- [40:43]
B
You have to be choosier about your mates. Exactly. Sleeping with or mating with lots and lots of males. Less useful for females than for males. But. So parental investment is really the core to.
- [40:56]
A
Is that the key driver?
- [40:58]
B
Well, I think the key driver is the difference in the maximum offspring number or the reproductive variance.
- [41:03]
A
Right.
- [41:04]
B
Because it's not just shaped by parental investment.
- [41:06]
A
Behaviorally, that shows up as parental investment.
- [41:08]
B
Well, that's a big part of it, yeah. So the parental investment is the major cause of the sex difference and maximum offspring number. But other things do come into it in different species.
- [41:18]
A
Gestation period, too, is like a biological imposition on parental investment. Parental investment. Right. Actually is how long it takes to just make a baby considered part of parental investment.
- [41:30]
B
That is part of parental investment.
- [41:32]
A
Yeah.
- [41:32]
B
And parental carers and nursing is obviously
- [41:35]
A
those two, but I wasn't sure whether or not it's classed. Parental investment is classed as actually the making of the baby.
- [41:41]
B
It is because it forecloses the option to make other babies.
- [41:43]
A
Understood. Yeah.
- [41:44]
B
But ecological things come into it as well. So one example of a factor other than parental investment that influences the reproductive variance is ecological factors. So you'll have some species where the males. Where they're quite solitary, so the males and females might pair up and there aren't many other individuals around. Even if the female invests a lot more in the young than the male does, their maximum offspring number is about the same because, just simply because they're isolated from other members of the species, the males don't have many other opportunities to sow their wild oats.
- [42:19]
A
What's Bateman's principle?
- [42:20]
B
Bateman's principle. So that is the idea that reproductive variance is greater in. In males and females in most species. And then Trevor's sort of refinement of that was that the main cause of that is parental investment. So Bateman put a lot of it on anisogamy. He explained the difference in reproductive variance in terms of the fact that females invest more per egg than males invest per sperm. Trivers said. Robert Trivers, who died recently, he said it's not just that, actually. It's so all kinds of investment that you put into the young, not just the gametes, but also gestation and parturition, which is giving birth, nursing, parental care, all those things are what matters. And I would just add that parental investment is the big one. But other things as well determine reproductive variants.
- [43:11]
A
What is the. It's about 40% of males that have human males ancestrally reproduced in about 80% of females, is that right?
- [43:20]
B
I Have heard that number bandage about. I actually think that probably in our species, my guess is that it's not that big. I've also seen other evidence suggesting that it's called reproductive skew and suggesting that the reproductive skew in our species is quite a bit lower than you find in most mammals. And I think the reason for that is that.
- [43:41]
A
So the 4080 number you think is wrong?
- [43:44]
B
Yeah, right.
- [43:44]
A
Okay.
- [43:44]
B
I think so. I think. What's the reason it's a smaller. Well, I think it's smaller and I think because males in our species very often invest quite a lot in the young. So it's not just the sex act. They often typically help out with the young as well. And so we have high levels of biparental care in our species. That reduces the maximum offspring number for males relative to females and brings it down, brings it closer to what we have for females.
- [44:11]
A
So if other animals have less of a reproductive skew but also have less male parental investment, how would the reproductive skew for us be so great if we have more male parental investment? Is that what you're saying?
- [44:25]
B
That is what I'm saying.
- [44:25]
A
Bingo. I fucking know. Evolutionary psychology, dude. Don't test me on this. I fucking understand this. It's the only topic I understand.
- [44:33]
B
Yeah.
- [44:33]
A
So variance in reproductive success, what do you reckon it was then? If it's not 40, 80, feel free to just bro science it. There's a cap you can put.
- [44:45]
B
I probably shouldn't put a number other than to say I think it's smaller. I know, I know.
- [44:54]
A
I'm in the room, dude. That'd be just fine. Put this thing on for the rest of the conversation.
- [44:58]
B
Oh, you've got bees as well.
- [45:00]
A
That's if you want to say something insane.
- [45:02]
B
Okay, cool. Well, I'll keep it here because I
- [45:03]
A
may well want it to say something absolutely insane. You're allowed to put that on. It's actually saved me once already. I got clipped. Talking about a slightly highly postulated theory. Put that on. It's going to be interesting on you because you already have the mustache and the glasses.
- [45:16]
B
Well, indeed, yeah.
- [45:17]
A
Nothing's changed.
- [45:18]
B
Nothing's changed.
- [45:25]
A
Yeah. Okay, so we've got a. It's like an interesting, I guess an interesting pivot on what people think. That sort of 4,080 number, as far as I was aware, actually. So you think the skew is different. What I thought might be true is that the overall number might be different too. That the whole. To me like infant mortality.
- [45:49]
B
Right, right, right.
- [45:50]
A
Fucking ruthless. So the only way that we can work out how many of our ancestors reproduce, presumably is due to some kind of genealogy stuff. And that means that it's not how many reproduced, it's how many survived.
- [46:04]
B
Yeah. Survived to reproduce.
- [46:05]
A
To reproduce. Yeah. It's a grandparent optimizing machine. From your last book. Yeah, previous book. Which is fantastic. And everyone needs to go and look at. Yeah, people understood the universe. 80% of women having grandchildren producing or 80% of women being grandchildren producing people seems insanely high to me.
- [46:30]
B
I guess the thing is that they would have had a bunch of kids and only about 50% would make it. About 50% would make it. And so if they have sex, for instance, that's what it is.
- [46:39]
A
Around about 50% that are born go on to reproduce.
- [46:43]
B
Unbelievably high, right? About 50% infant mortality rate. So like half of them didn't make it. One of the great things I think, of our civilization is that we have lowered that number to very close to zero. Because that was, I think, a massive cause of misery throughout most of human history.
- [47:01]
A
Was it Darwin lost a bunch of kids.
- [47:03]
B
He did, yeah. He had. What was it? He had 10 and three didn't make it to adulthood. I think that's the numbers. Yeah.
- [47:10]
A
Is it your book or was it. I think this might have been the moral animal where Robert Wright talks about the fact that Darwin lost multiple children, but the one that was the most psychologically painful was his daughter, who was 12 or 13. And the reason for that, the evolutionary reason that Robert gives for it, is that that parents are able to detect the moment at which the life cycle of their child would have allowed them to just about become the grandparent optimizing machine that evolutionarily were driven to be. And that if a child dies at 2 years old, that's horrible. But they weren't. They had a long way to go. And many things could have occurred between now and being able to have kids. If a child dies when they're old, then they've had all of the opportunities to have had kids. And that didn't. That didn't go well. Or maybe it did go well. But if you are just on the cusp of being able to reproduce biologically and you die, that is, from an evolutionary perspective, the most painful. Am I making that up or is that the story?
- [48:24]
B
No, that is the story. Yeah. And there's pretty good evidence on it as well that grief tracks reproductive value of the individual.
- [48:31]
A
No fucking way.
- [48:33]
B
So this has been reproduced because that
- [48:34]
A
book's 30 years old.
- [48:35]
B
That. Yep, yep, yeah. Go the Greek average grief levels go up and up and up as reproductive value goes up as, as kids move from the very vulnerable, historically very vulnerable early infancy to childhood. It's kind of peaks at about the age that reproductive value peaks. So a couple of years after puberty and then it starts coming down again as people get older.
- [48:58]
A
That's so fascinating. How is everyone not obsessed with evolutionary psychology? So cool.
- [49:03]
B
Fascinating, right? It's so fun and sheds light on some of the most fundamental stuff in life.
- [49:07]
A
Yeah, I mean obviously it's very bleak in some ways too. It's very stark. It doesn't paint a particularly flattering picture of human motivation. The reason that Darwin was particularly Sad about his 13 year old daughter dying is that he had this weird algorithm running in the back of his mind that he said, oh, so you're just saying that all that children are. That produce chance for you to be happy to do things, it's like, dude, you, you don't need to laud our ultimate evolutionary drives in order to understand and respect them and accept the fact that they are important influences on our behavior.
- [49:44]
B
I completely agree. And I do feel the pull to what like it is a bit bleak. I remember when I was first reading about that grief theory, it does seem a bit dark. But then when you reflect it. But it's not very flattering. Exactly. I mean, I guess one thing is that we're not actually thinking about reproductive value. We just have a built in tendency to react as if we are, but we're not actually thinking in the back of our minds. This is sad because this kid was close to having kids and then I would.
- [50:15]
A
This is sort of my least. I don't know. Actually. I probably could write out a hit list of my least favorite Internet rebuttals to anyone talking about evolutionary theory. But. But one of them is a lack of understanding about the difference between proximate and ultimate motivations for behavior.
- [50:34]
B
Yeah, exactly. So one of the big ones. Yeah, like the big misunderstandings.
- [50:37]
A
Why you feel the desire to do a thing and the evolutionary advantage of you doing the thing. The fact that those two things are different. You eat food because it tastes good, but the reason for eating food is to keep you alive. You have sex because it feels good, but the reason to have sex is not the reason that it feels good.
- [51:01]
B
Exactly. Right. And it's quite annoying. Right. When people say so you're saying that like sex and having like short term relationships or long term relationships is just about babies. But that can't be true because often the last People. The last thing people want is to have kids, and they don't want to have kids. Birth control.
- [51:17]
A
I'd love to have sex.
- [51:18]
B
Yeah, yeah, yeah, Exactly. So it doesn't make sense, but they've just misunderstood the idea because it's not a psychological theory like the genes. I view explanations, the evolutionary explanations, those are not motivations. Those are just the explanations for why we have the proximate psychological drives that we do.
- [51:35]
A
Not the ultimate.
- [51:36]
B
Exactly.
- [51:37]
A
Yeah, yeah. And, you know, with the. What's it referred to as. That theory of the sexual. Not sexual value of Darwin's daughter dying. What's the.
- [51:50]
B
Oh, yeah. Reproductive value.
- [51:53]
A
Reproductive value. No. 1 is. How horrible to say to a parent. Well, it's actually, Mrs. Thompson, the reason that your grief. Mrs. Darwin, the reason that your grief is so high is because of the reproductive value that your daughter almost didn't cash in on. Horrible. Horrible thing to say. But it doesn't need to. It doesn't need to be something that's in your mind to, like, go, how could you claim that this mother is feeling that, Thinking that at the time, and that's contributing to her grief. No.
- [52:23]
B
Yeah. She just loves the kid.
- [52:25]
A
Yeah. And it would be the same as going, why is it that people get depressed when they're lonely? I'm not thinking about potentially being kicked out of the tribe. And you go, well, yeah, like, we're in a modern environment. Why do you think it is that depression and anxiety correlate with isolation? Yeah. If it didn't matter. Well, it does matter. It doesn't matter anymore. Not in the same sort of a way. But that doesn't negate the fact that our system is basically ancient programming, living in a modern world.
- [52:52]
B
Exactly. And even though it does seem bleak sometimes, I don't see that other explanations, sociocultural explanations, would be any less bleak.
- [53:00]
A
You know, I'm at the mercy of the memes and trends of the modern world.
- [53:05]
B
Well, exactly. And some guy decides to start a
- [53:09]
A
new cool movement somewhere, and then that completely sort of blows the wind of whatever it is that I'm supposed to care about.
- [53:16]
B
Exactly. Or you might say, okay, the reason that you grieve this individual is just because you've been socialized to do so. And how is that any less bleak?
- [53:24]
A
It's the same. This is why I think there's a lot of similarities between evolutionary psychology and behavioral genetics, that if you start to strip away the science and the evidence underneath it, what you end up with is an equally or maybe even uglier perspective in the world. For instance, if you deny that there are genetic influences on outcomes in life, what you're left with is this world where everybody did start off equal and you are exclusively at the mercy of the entire world and injustices. Yeah, yeah. The only reason that this didn't come out is all on your shoulders. It's all on your shoulders because you didn't try hard enough or your parents didn't try. Try hard enough. Horrid. Horrid.
- [54:08]
B
And I guess though, the thing is that whatever. Horrid truth. And they're not all horrid either, but whatever hard truth, ultimately we just got to accept what's true. Whether we like it or not. Sometimes it is positive. So natural selection has given us a whole range of less than noble traits, but it's also given us some really lovely traits as well, like the capacity to fall in love and to love our children and to love our friends. You know, these are all great brothers.
- [54:35]
A
So I guess just to round out the. We haven't even got into the sex differences yet, which is the meat and potatoes of this, but I don't care. Is it. Are humans unique in this regard because we've got mutual mate choice and we've got bi parental care. So when we're talking about evolution of sex differences, parental investment, ability to produce children, or volume of children across a lifespan, Bateman's principle variants and reproductive success. But humans do seem to be somewhat of an outlier in mammals and especially in the animal kingdom.
- [55:13]
B
Yep, yep.
- [55:15]
A
What wrinkle does that throw in?
- [55:18]
B
Well, yeah, so we are. So the question are we unique? Sort of, yes and no. So the way in which we are unique, we're very unique among mammals, like you say, in the fact that we have high levels of the tendency to pair bond, so to fall in love and form relatively durable pair bonds and for both sexes rather than just the females, to invest in the young, that is found in maybe 5 to 10%, 10% at the most of mammals. So the overwhelming trend among mammals is that the females do all the investment in the young and the males are basically deadbeat dads. In birds, on the other hand, they are an outlier family of animals among animals in general, and that around 90% of birds form pair bonds and have biparental care. And so there's a funny thing, and I find this just very, very interesting, is that in our primary reproductive behavior, humans are more like the average bird than like the average mammal.
- [56:13]
A
No way.
- [56:14]
B
Yeah. That's because of our pair bonding and
- [56:16]
A
our biparental tendencies, which is a reinforcement that the parental investment is the key driver of sex differences.
- [56:28]
B
Yep, exactly. And of the difference in most birds.
- [56:33]
A
Hang on a second. Yeah, so most birds are kind of like dinosaurs and humans are closer to birds than they are to most mammals, which means that humans are kind of dinosaurs.
- [56:44]
B
Yeah.
- [56:44]
A
So that's evolutionary logic.
- [56:46]
B
That's great. That's great. Do you want this?
- [56:47]
A
Yes. No, No, I don't need that. I don't need that.
- [56:49]
B
No, no, you don't, because I agree. So we're mammals that are more like dinosaurs in terms of having the primary reproductive arrangement of today's dinosaurs.
- [56:59]
A
Let's fucking go.
- [57:00]
B
It's wild, right?
- [57:01]
A
Let's fucking go.
- [57:02]
B
And so, yeah, so we're an exception among mammals in that respect. A way in which we're not an exception, though, is that the same evolutionary principles that apply right across the animal kingdom apply to us as well. So the fact that sex differences emerge from the maximum offspring number, the level of sex differences and reproductive variants, that is true across the animal kingdom and the rules about that apply to us as well. And the fact that we have. We do have a sex difference in reproductive variance. Men do have and have always had greater reproductive variance than women, but it's relatively low compared to most mammals.
- [57:41]
A
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- [58:51]
B
Actually most insects it's that way around. And actually there are more animals where the females are bigger than where the males are bigger. But that's not because of the difference in reproductive variants. It's because in a lot of species the main driver of sexual dimorphism is just the number of eggs that you can produce. And females, bigger females can produce more eggs. So there's a selection pressure on them to get bigger and bigger and bigger. They're typically bigger than the males. The males just don't need to be
- [59:19]
A
much, they don't need that much room for sperm.
- [59:21]
B
But yeah, exactly, yeah. So the gamete size difference, sperm are bigger than eggs, is reflected in the physiology of the species.
- [59:28]
A
That's so cool.
- [59:30]
B
And we're the weirdos. We're so used to males being bigger than females. But actually mammals and other large vertebrates, we're the exception to the rule. And the main reason for it is that you still have the selection pressure on the females which of producing more eggs. So you know, they got certain size sort of push for them to be bigger, but you got an even stronger push on the males to be bigger as a result of intersectional selection, which is selection for the ability to be able to beat each other up basically. So a lot of species, bigger males do better in fighting than smaller ones. Males get bigger than the males get bigger and sometimes they get even bigger than the females.
- [60:07]
A
All right, meat and potatoes. Getting back to sex differences in sex drive.
- [60:11]
B
Yep.
- [60:12]
A
What casual sex, sexual variety, cheating, what's going on there?
- [60:17]
B
Yep. That's all about producing more offspring. So a male that is equipped with those motivations is going to be sort of like a heat seeking missile going out to seek multiple partners and is therefore more likely to have more offspring if he's successful than that than he would if he just sort of sat back and wasn't interested in multiple partners. And you do find that in many species. Now I don't think that the difference is as big in our species as in many others. And I think that's a side effect of the fact that because we have bi parental care, the level of reproductive variance among males in our species is somewhat constrained, still greater than among females. But because it's somewhat constrained, sex differences in our species have correspondingly come down as well. So we still have all the traditional sex differences, differences that you find in most mammals and many other species, but they're somewhat muted. So you have the sexuality sex differences, but they're somewhat Muted the aggression differences, but they're somewhat muted. The parenting differences is the main source of this. So that is like the discrepancy in male investment in kids versus female investment has been massively reduced.
- [61:31]
A
And that's the driver and that's the parental. The bi. Parental investment is the nerfing, the reason for the nerfing of all of the others. Okay, again, I'm only gonna make this fucking disclaimer once, but we said it previously, but I think it's worth saying again, just because we can explain using evolutionary logic, the reason why men might be driven to cheat more than women is not the same thing as excusing why it happens.
- [61:58]
B
No, not at all. Any more than a sociocultural explanation would excuse it. That's a funny asymmetry. People seem to think if you explained in evolutionary terms that excuses it. But there's no more reason to assume that than to assume that if you explained it in sociocultural terms.
- [62:12]
A
Because with both of those you are outsourcing the culpability of the individual to something else. In one it's evolution and ancestors, and in the other it's culture and influence.
- [62:23]
B
Yeah, exactly. And all our behavior must have causes, Right? So if we're gonna say that if we can identify the cause of a behavior and it's an evolutionary cause, we're going to have to not hold people to blame. We're going to have to say that for any cause and we're going to have to say that for all behaviors. Because all behaviours have some kind of cause, whether or not we know what it is, they have some kind of
- [62:42]
A
cause, whether it's evolutionary or cultural or
- [62:44]
B
most likely a combination of both. So I think that basically the institution of holding people responsible, we have to keep that institution because it's useful, regardless of the fact that of course people's behavior has causes and it's not inexplicable.
- [62:57]
A
That's so good. Good. Ashley Madison. The cheating website had 20 million active male users and 1,492 active female users, despite women getting free lifetime membership and men having to pay.
- [63:09]
B
Yeah, that's wild, right? That's a massive difference.
- [63:12]
A
20 million to 1,500.
- [63:16]
B
It's probably similar to that ratio we had up there before.
- [63:19]
A
It's almost exactly the same. Yeah. What about men being more turned on by visual triggers?
- [63:24]
B
Yeah, that's another big sex difference. Both sexes are to some degree, you know, both sexes are interested in good looks in a mate, but it's stronger in men than in women. And the main Reason for that is that the traits that we consider good looking are associated with youthfulness and fertility for both sexes. But men place a greater weight on those traits because of menopause, basically. So the fact that they place more weight on youthfulness in a mate because youthfulness is more closely linked to fertility in women than men, because of the fact that women's fertility shuts off about, you know, 2/3 of the way through the lifespan. Yeah, so yeah. So men much more interested in visual sexual stimuli as psychologists call it. It's part of the explanation for the fact that men are much more avid consumers of porn than women are.
- [64:14]
A
What is the reason that women are much more avid consumers of romantasy and romance novels than men?
- [64:21]
B
It's an interesting one, isn't it? So that's the standard sort of differences in consumer preferences that we hear about. Men are much more into porn than women. Women are much more into romance novels. Now it is interesting. We've talked about the fact that men on average are more interested in casual sex than women and people often assume that the flip side of that is true as well, that women are more interested in long term relationships than men. But actually that's not the case. Typically what we find is that men and women are about as interested as each other in long term committed relationships and falling in love and form a committed bond with a partner.
- [64:58]
A
So you haven't reapportioned the sex drive, relationship drive desire from short term to long term for women. It's just that they don't have this addition that men do of the one night stand.
- [65:12]
B
Exactly right. But bearing that in mind to the same degree. Yeah, yeah, yeah. Bearing that in mind. The fact that women are so much more interested in, in romance novels is interesting and sort of slightly unexpected. You might expect that both sexes would be interested in them. So why it is the case that women are more interested in them, I guess, evolutionarily speaking, I don't know. They do seem to be, despite the fact that actually men do seem to be very invested in long term relationships. A bunch of papers have come out recently actually saying that in a lot of ways men are kind of more romantic than women. They are more likely to suffer after
- [65:49]
A
a breakup, fall in love more quickly, say I love you more soon.
- [65:52]
B
Exactly, exactly. So why aren't they more into romance novels? I don't know, maybe they're just too busy with the porn.
- [65:58]
A
But yeah, true dude. I mean I sat next to a lady, lovely lady, floral dress, slightly older lady, on a flight a few months ago and she had an iPad up resting it and it was a big fuck off font and she was reading some romantasy thing and she was getting to the good stuff. And I mean I couldn't. I was. We have legalized. We have legalized women reading porn in public. And it's not. I mean it was. She was having a. She seemed to be having a wonderful flight. And I got my. When someone sits next to me and they've got an iPad, I think, oh that's, that's great. Cause it's gonna. Or whatever, the Kindle or something, it's gonna influence me to be. Not be a degenerate. All I wanted to do was put a pair of blinkers on and like some brain slop stuff.
- [66:46]
B
I've never, I've never. I've been meaning for ages as a sort of anthropological study.
- [66:52]
A
However you want to do it. Excuse it. However you want.
- [66:54]
B
I haven't got around to doing it. I'm going to do it. I'm going to read a romance novel at some point. I have heard that the general theme is boy meets girl, boy is a bit of an asshole, girl tames boy and then they live happily ever after. And they do involve sex, right?
- [67:07]
A
Well, yeah, I mean there is some sex in them. At least there was in hers and
- [67:11]
B
the one that she was reading.
- [67:11]
A
Yeah, exactly. I mean there's some interesting stuff, right? The number of. If you have a single. A sexual fantasy, mental sexual fantasy, men will cycle through. I think it's between four and six different partners on average.
- [67:25]
B
During it's four and six or 46.
- [67:27]
A
Four and six, I think. But it depends who you are. Whereas for women, they tend to have fewer or maybe maybe just one. Now I don't know, but I'm gonna guess that this would be reflected in romance novels. In fact, I know that this is the case because I've been on the COVID of a bunch of them. And during those novels at least I would say on average most the women who are the protagonists aren't cycling through multiple male suitors. And if they are, even if you look at movies, movies like the Notebook or Titanic or whatever, it tends to be a pivot between two different life directions. It's not a kind of ruthless conveyor belt that is closer to sort of the typical male fantasy. But yeah, the men being more turned on by visual triggers thing I think makes an awful lot of sense. I remember in Bad Men Bus's book he talks about how there is an area of the brain that exists in men that lights up when they just see something that's remotely sexual. A pair of rocks that look like boobs.
- [68:34]
B
Pulling a coin into a vending machine.
- [68:36]
A
Putting a coin into a vending machine. You're fucking kidding me.
- [68:38]
B
Although it was a joke. I'm not sure there's actually research, but
- [68:41]
A
that kind of thing that honestly wouldn't surprise me.
- [68:42]
B
No, no.
- [68:42]
A
Likewise, there is something penetrative about gambling. And on top of the risk taking. On top, that's it. Overperception bias as well. Another great example that I learned from Bad Men by David.
- [68:56]
B
Yeah, yeah. And that's research by him and spearheaded by his former student, Marty Hazelton. Yeah, the sexual over percept bias. Yeah, that refers to the fact that men are more likely to infer sexual interest on the part of a woman, falsely, like falsely infer it than women are in the case of men. So they're more likely to think, yeah, she's into me, when actually they're just in a little dream world. And that's not actually true.
- [69:23]
A
Men are more likely to think that women are interested in them than they are. And women are more likely to think that men aren't interested in them when they are. And I think that the data shows the level of attraction that men assume a woman has toward them is roughly equal to the amount of attraction that the man has toward the woman.
- [69:45]
B
Yes, right. Yeah, exactly. So it seems to be maybe some kind of projecting yourself into the world kind of bias.
- [69:52]
A
Yeah, so it's a failure of cross sex mind reading. But it's also specifically in an over perception by here too. And this is smoke detector principle. If you as a man had the opportunity to potentially bag an available and attractive woman and because you weren't sufficiently vigilant and detecting it, because you underplayed your potential success likelihood as opposed to overplayed it, you are going to have an error of missing the opportunity as opposed to the error of an awkward and clumsy rejection.
- [70:23]
B
Exactly.
- [70:24]
A
And this again, fuck, I'm just gonna have to keep saying it does not excuse guys in the workplace with the receptionist in the printing room having an awkward fumble that she absolutely didn't give off signals for. However, this does explain how you get to that situation or why it is that on average men seem to be. Unless you're the CEO of who is it? Procter and Gamble. Who is the one that that Indian dude made the whole fucking conspiracy theory about it went insanely viral. I bet your fish head Asian wife doesn't have these cannons. Do you remember that?
- [71:00]
B
Goldman.
- [71:01]
A
Goldman Sachs. Goldman Sachs. Yasmin's. Mum works at Goldman. We should get the inside scoop. Yeah. My guest Bucket's mum is like real high up at Goldman Sachs. And then there was that huge. Did you see this thing kick off a couple of months ago?
- [71:15]
B
I don't think.
- [71:17]
A
No, it was a guy. Me tooing. A very, very high up.
- [71:22]
B
Right, okay.
- [71:23]
A
Exec.
- [71:24]
B
Yeah. A bit of a role.
- [71:25]
A
Goldman. But as soon as the proposed accusations came out, there was no. It was so rare. It was. At the most it would have been incredibly extreme.
- [71:36]
B
Yeah.
- [71:36]
A
For a guy to do.
- [71:37]
B
Yeah, yeah, yeah.
- [71:38]
A
And the fact that everybody intuited like really.
- [71:42]
B
Yeah.
- [71:43]
A
Sex differences.
- [71:44]
B
Yeah.
- [71:45]
A
All right. How do. How do gay men and lesbians reveal what each sex wants?
- [71:50]
B
They do so in a very interesting way, which is that gay men have more casual sex than straight men and lesbians have less casual sex than straight women. And the reason is that gay men and lesbians don't have to compromise with the typical sexual inclinations of the other sex. And therefore their behavior is like a clearer window onto the sexual motivations of men and women in general.
- [72:16]
A
Unsullied by the other sex.
- [72:17]
B
Exactly. Yeah. So men are compromising by having sex less because basically women are thwarting their plans.
- [72:23]
A
There's no gatekeeper.
- [72:25]
B
Exactly. And yeah. Whereas straight women are compromising with men and maybe having more than more casual sex than they would choose, at least as revealed by lesbian behavior.
- [72:36]
A
There's an interesting study that Rob brought up which was inside of marriages. Typically men say that they would like to have twice as much sex as they are having. And women say that they are happy with the amount of sex that they are having, which suggests that there is a compromise going on, but that the
- [72:53]
B
compromise is the guy going, okay, fine, she's setting the level more than he is.
- [72:59]
A
With that regard, I do think that there's kind of a. And this is. I mean look, are we really gonna say boohoo? Poor men not getting exactly what they want. But I do think that it's a. A kind of compromise that might be invisible to women because sexual entitlement comes wrapped in some really ugly paper. But there is an argument that you can make there to say something like, look, men are doing a type of containment, a type of desire containment there that isn't a burden. That is that they are paying. There is isn't being paid in the same way inside of a marriage by the women. And huh. That's well done. Well done for doing that. For compromising what it is that you want.
- [73:48]
B
Yeah, indeed. And I guess, and I Guess it's more, it's more, I guess that men are doing that more often. Some women are doing the same thing, no doubt, but it's just fewer women than men in that situation.
- [74:01]
A
Yeah. There's also more dead bedrooms in lesbian relationships.
- [74:06]
B
I've heard that. Yeah. What is the, there's some, some phrase like that, isn't there? The lesbian deadbed or something. Yeah, yeah.
- [74:13]
A
Okay, so mate preferences.
- [74:15]
B
Yes.
- [74:16]
A
When it comes to mate preferences, is it surprising how similar men and women are when it comes to what they look for in a partner?
- [74:25]
B
Well, I guess it fits with the generalization that in a lot of ways we are quite similar. Similar that we. Sex differences in our species are not as huge as in some others. And I guess also just on a everyday level, when you hear about some of the sex differences that we have in common, they're all things that I think it's obvious why we like them. People tend to be men and women tend to want somebody who's pretty intelligent and who's kind and who loves them and who is attracted to them and who is pretty good looking and who's not mentally unstable. Both sexes want that, not just men, not just women. There are some areas though where you do find sex differences in the strength of different preferences. So both sexes want someone who's pretty good looking, for instance. But on average in long term relationships, that's a bigger deal for men than for women. Men put more weight on looks in a mate than a long term mate than women do, for the reasons that I mentioned and that I mentioned earlier. Women, on the other hand, tend to put more weight on resources and status and a long term mate than men do. Now in neither of those cases is that it's not like looks are the most important thing to most men. For most men it's important. But other things are equally important or even more important traits like kindness. And likewise with women, resources and status in a mate, they're important, but other things like, again like kindness, tend to top the list of the things that are most important for women.
- [76:01]
A
Most people don't realize how much being dehydrated impacts their performance. Which is why for the last five years I've started pretty much every morning with Element. Element is a tasty electrolyte drink mix with everything that you need and nothing that you don't. This orange salt in a cold glass of water is like a sweet, salty, orangey nectar. And I really tell the difference when I take it versus when I don't. It plays a critical role in reducing muscle Cramps and fatigue helps to optimize brain health and regulate your appetite while also curbing cravings. Best of all, they have a no questions asked refund policy with an unlimited duration. So you can buy it and try it for as long as you want and if you don't like it for any reason, they'll just give you your money back. Plus they offer free shipping in the US right now. You can get a free sample pack of elements most popular flavors with your first purchase by going to the link in the description below or heading to drinklmnt.com ModernWisdom that's drinklmnt.com Modernwisdom what's the evolutionary logic of non physical mate preferences like wealth and status?
- [77:01]
B
It all comes down I think to the fact, well there are two main explanations for it. So one is that it's part of our evolution of a pair bonding bi parental species. So a guy who is able to access resources, bring in food and also has good standing within the group, that's going to be someone who is better able to invest in the young to co rare the children. And that's the explanation I think is most popular and most likely there is also an explanation though that it's primarily a human equivalent of the peacock's tail. So that any male that is capable of bringing in resources and climbing the status hierarchy, that's a male who's got got good genes and he's gonna pass on whatever traits enabled him to do that to his male offspring, they're gonna be able to do the same, they're gonna attract more mates. So those are the two main explanations. I think it's quite possible that both of them shed light on it, that it's both a fitness indicator but also is actually useful in the context of biparental care.
- [78:02]
A
You mentioned this is to do with long term relationships.
- [78:06]
B
Yeah.
- [78:06]
A
How does this change when it comes to short term relationships? Do women place more or closer to equal weight on physical attractiveness in men?
- [78:16]
B
They do. They do, yeah. So that sex difference in good looks, we sometimes hear it discussed as if that's a difference between men and women right across the board in every context. But actually it does just apply to long term relationships. And when it comes to low commitment relationships, then that difference basically evaporates and women are at least as interested in in physical attractiveness in a mate as men are. If not, some research suggests he may be even more interested in physical attractiveness.
- [78:43]
A
Why would that be the case using evolutionary logic?
- [78:46]
B
Well, the best explanation is that in a short term Context that's likely to be. Basically there's going to be no further investment. Probably likely no further investment. The only investment is the gene that the male is going to be passing on. And therefore traits that are indicative of good genes are much more important. They take centre stage in terms of what women are looking for. And yeah, with the basic evolutionary logic that when you're reproducing you are finding somebody to mix your genes with. If you want your genes to go on in the gene pool, you've got to mix them with a good set of genes from another individual.
- [79:29]
A
And what you want, if you have a short window to do this assessment in, you want the most obvious representation of those good genes as you can.
- [79:37]
B
Exactly. And physical looks are bad.
- [79:40]
A
I'm sorry, your ability to do non kin altruism and reciprocal care and kindness and your ambition over time, it's like, yeah, great, but I don't have time to assess that in the same way as I do your status and your resources. I suppose it's another one of the reasons. And both men and women, if this sex difference didn't exist, if this preference didn't exist, why would it be the case that both men and women seem to play into a caricature of that in an attempt to get sexual access? Why is the caricature of dudes in Miami nightclubs wearing a Rolex and having a fast car outside? Yeah, well that's a way to turn wealth, ambition and status, buying a VIP booth status into an immediately transactable and obvious advertisement in case there is some of this short term mating that's going on. Why is it that women do more beautification when they go on a night out, et cetera, et cetera. Like because you're playing into, even if you don't intend on doing it, it's always nice to sort of be window shopped against, I suppose.
- [80:46]
B
Totally. And it's interesting, right, because these are human equivalents of the peacock's tail. And whereas in peacocks and every other species, basically their peacocks tails are non negotiable. That's just how they do it. Whereas we, because we're a cultural animal, we always have our peacock's tails, we always have our way of showing off status and whatever else resources. But it varies from culture and culture and time to time.
- [81:10]
A
Why isn't it that women aren't turning up in a fast car with an expensive watch outside?
- [81:14]
B
That's a very interesting question. And I guess because that's more indicative of resources and resources are more important to women than men? I don't know. There was this study where this guy. It wasn't a study actually. This guy in his class, his evolutionary psychology class, he was showing a photo of this amazing Rolex and people saying how great it was and what a great way of attracting a mate that it would be. And then he revealed the trick was that actually it was a woman's Rolex rather than a man's. And his point was that actually this goes both in both directions more than we kind of think it does. Yeah.
- [81:55]
A
Have you seen, I think it's Andrew Thomas that did this study. Have you seen the preferences that women state when it comes to sperm donors?
- [82:08]
B
Yeah.
- [82:09]
A
So this is fucking fascinating because what's interesting is when you run a kind of a split test or you're able to separate out certain motivations from a behavior that people are typical with. So in order for you to do the I want to have kids with this person, typically you need to go through courtship phase and get to know them and even if it's a one night stand, be seduced by them. But that means that you're optimizing for two different things. You're not just optimizing for the genes that your kid gets, you're also optimizing for the expression of traits that make you want to get into bed with somebody. But if you get rid of the seduction side of this, all you're optimizing for is what do I want my kids to have from a trait perspective. And that difference of when you get rid of the need to actually be attracted to somebody and you can just optimize for what do I want my kids to be like kind of fascinating?
- [83:03]
B
It's really fascinating. Right. And just the same mate preferences emerge in that context as emerge in an actual interactions, social interactions.
- [83:12]
A
There's that Clark Hatfield study as well, right? The on street interview.
- [83:17]
B
Yeah, yeah, that's the one where basically they got a bunch of good looking guys, good looking gals to go around a campus on a nice day, walk up to random people on the campus and just say, hello, how you doing? I've noticed you around the place lately and find you very attractive. And I was just wondering whether you wanted to. And then they would finish that sentence with one of three options. Option number one was I was wondering if you wanted to go out with me tonight. Option number two was I was wondering if you wanted to come up to my room. And option number three was I wonder if you wanted to go to bed with me. And they got men to ask Women, Women to ask men. And for the first question, the go out with me question in the first study they did, there was basically no sex difference. So it's about 50%, 50, 50 likelihood of saying yes in both cases. Other replication studies have found that it's not a huge difference, but that actually men are more likely to say yes than women are. But then with the other two questions, the gaps get bigger and bigger. With question number two, which is, would you want to come up to my room? What was it? It was basically 67. In the first study, about 67% of men said yes. So actually higher than the date rate.
- [84:32]
A
More likely to go up to your room than I am to go on a date with you.
- [84:34]
B
Exactly.
- [84:34]
A
Hilarious.
- [84:36]
B
With women, on the other hand, it sank down to. I believe it was 6% said yes to that. And then the gap was even bigger for the last question, unsurprisingly. So would you go to bed with me? 75% of men said yes to that offer. So an even higher rate of men, whereas exactly 0% of women and said yes to the kind offer. And not only that, but actually the manner of the refusal differed between men and women. So of the 25% of men who said, thanks, but no thanks, well, they kind of said that they were polite about it. And some of them said, I'm really sorry, I'm meeting my fiance, or whatever. A bunch of them even asked for a rain check. Apparently they said, I can't, I'm very busy, I'm meeting my fiance, or whatever, but maybe we could postpone the sex tour later. Whereas none of the women who were refusing were polite about it at all. They were directed more like, are you crazy? How dare you ask me that? None of them apologized and asked for a rain check.
- [85:37]
A
Why do you think that the manner of refusal was so different?
- [85:42]
B
I think that it reveals two reasons. So one is there's this average difference in interest in casual sex because men are more interested in it. They are more likely to be flattered by the request, because men are much more likely to approach women than vice versa. Traditionally, women are much more likely to get sick of it and to have to push guys away, whereas guys are much. It's a rarer event for them. So they are more likely to be flattered and hugely grateful on the rare occasions when it happens. The other thing, though, and the reason I think the difference is quite so big, is because it's not just a reflection of sex differences and interest in casual sex. I think also in that situation, like, if a woman were to go off with a guy that she doesn't know, she's at a greater physical risk than if a guy goes off with a woman that he doesn't know. So the fact that the difference was massive is partly due to that as well.
- [86:43]
A
Feels like a danger.
- [86:44]
B
Exactly.
- [86:45]
A
Some of that emotional activation of. Hang on, I'm gonna go with this person who I don't know who is physically stronger than me. Explosion.
- [86:54]
B
Exactly.
- [86:55]
A
As opposed to this just way less of a. It feels less of a physical threat to me.
- [86:59]
B
Exactly.
- [87:00]
A
Those both make complete sense. There's an interesting wrinkle in this. Now I'm gonna guess that when they did this, the Clark Hatfield study, they must have have done some sort of rated assessment of the attractiveness of the man or the men versus the women to ensure that they were similarly high in terms of physical attractiveness. Yeah, right. Yeah. So something that I learned that I think is absolutely fucking hilarious is one of the reasons why women, and I presume men would be too if women approached men at the same rate. One of the reasons why women are sometimes quite rude when guys come up to them is if they feel like there's too big of a disparity in mate value between them and the person. Person doing it because they go, hang on, you think you've got a chance with me?
- [87:48]
B
Yeah.
- [87:49]
A
Oh my God. It's basically an insult. It's essentially an insult if you as a woman think that you're an eight. Nobody thinks like this. It's not the whatever podcast. You as a woman think that you're an eight and a guy that you think is a three comes up to you. That is it tests your own self perception and you go, fuck, maybe this is how the world sees me.
- [88:13]
B
Yeah. Do you not think I'm an eight as well?
- [88:16]
A
Yeah. Yeah. And I think that. That it feels like an insult and the same thing like fucking no, get away. Because rightly so you're kind of pissed that this thing happened.
- [88:26]
B
I wonder if guys would feel the same in reverse. See, my hunch is that they would be less likely to take it as a huge insult if the guy felt he was innate and approached by a three.
- [88:36]
A
Well, but I could preference for casual sex.
- [88:38]
B
Yeah.
- [88:40]
A
Rarer approach in any case.
- [88:42]
B
Indeed.
- [88:43]
A
And because women are less likely to approach, I think that most guys would actually see it as closer to, you know what? I'm so good looking that I got that girl to overcome her non approach predisposition.
- [89:00]
B
Yeah.
- [89:00]
A
That's the power of my attractiveness. I think that's How a lot of guys would take it and I think that's why it is flattering. It's like somebody running for a bus fast that they really, really want.
- [89:12]
B
Yeah.
- [89:12]
A
You're like, well you must really want this bus because look at how fast they're going. Suppose how slow they would.
- [89:16]
B
And guys tend to be more overconfident than women.
- [89:21]
A
Yeah. What about sex differences in aggression?
- [89:24]
B
Sex differences in aggression are very, very consistent, especially for direct aggression. So face to face aggression and guys predominate. And a really interesting fact about the aggression sex difference is that that for like verbal aggression it's there and it's significant. It's fairly modest though. So the effect size might be about like a 0.5 effect size. So half a standard deviation between the mean for men and women and maybe you know, pluck two people at random guy and a gal, two thirds of the time the guy's going to be higher in verbal aggression. But as you go further out to more and more intense forms of aggression, the size of the sex difference gets bigger and bigger with every step happen. So when you go to low levels of physical aggression, slapping, pushing, that kind of thing, you have a larger sex difference, men doing it more. Then you get into serious physical aggression, violent crime, that's much more men than women.
- [90:16]
A
It's independent of who the victim is.
- [90:18]
B
Independent of who the victim is. Yeah. And then when you get to the extreme of one on one aggression, which is homicide, Men vastly. Predominantly so across different cultures, every single nation, every data set I've ever seen, 90 plus percent of homicides are perpetrated by men. Men are also, they're the majority of the victims as well in almost all data sets that I've seen. But yeah, the 90% plus perpetrators, very, very strong effect.
- [90:48]
A
Yeah. Men commit more than 90% of homicides in every society on earth where data is available. And this gap is remarkably invariant across cultures, not just the absolute rates. In humans, males commit 95% of homicides and a 70 to 80% of homicide victims in chimpanzees. Male commit 92% of chimpicides and are 73% of victims. Virtually identical numbers to humans.
- [91:10]
B
Wild, right? Yeah. Now they are more aggressive than us. I think sometimes people hear that and they think that the claim is that we're just as aggressive as chimps. They are more. But the size of the sex difference in lethal aggression aggression is the same. And the size of the targets, the sex difference in the targets of aggression is about the same as well. Why that is a direct offshoot of the fact that the selection for getting to be one of the few males that has many offspring rather than the many that have few or none. And one of the ways that males do that is they compete with each other for status and resources which increase their mating opportunities. And so you get selection in many species, not just humans, selection for greater aggression in the males and particularly for greater male male aggression. Which is why you have this skew toward not only the other males more aggressive, but the targets of their aggression tend to be same sex individuals as well. For women and for female animals in general. They are capable of aggression in many species, but there's just less of a selection pressure. It's less useful for them evolutionarily to engage in same sex combat for status and resources because the fact that the ceiling offspring number that they have is lower. So they can't vastly increase the number of offspring they have by fighting each other and getting lots of status, resources and ultimately mates, you know that that won't boost the number of offspring they have because the ceiling is lower. So it's costlier for them. The costs aren't worth the risks.
- [92:45]
A
Yep. Plus more fragile.
- [92:47]
B
Yeah.
- [92:49]
A
More easily killed. Like just generally.
- [92:51]
B
Yeah. But that's possibly just an offshoot of the fact that there's been less selection on them for aggression. So there's been more of that to
- [92:59]
A
build up the defences in order to be able to. That's why we have a brow ridge. That's why we've got bigger hands.
- [93:04]
B
Exactly, yeah.
- [93:05]
A
Tell you what's interesting, again, talking to Andrew Thomas about this, he said why is it the case, if violence is rightly so, such a huge fear that most women have, that lots of women are attracted to powerful men who are able to be violent. And Andrew's theory is that it's a perspective that a guy who is violent is able to turn it on and turn it off in service of the family unit. As opposed to violence being a trait that just is more global across the. I think. Has Andrew done Krav Maga? He's into like martial artsy type stuff. I swear.
- [93:49]
B
I think so. Yeah.
- [93:50]
A
And he was explaining how many at Krav Maga, this Israeli martial art, very lethal, supposedly martial art. A lot of the guys that he trained with, unbelievably lethal physically.
- [94:05]
B
Yeah.
- [94:06]
A
And a lot of the training was them learning to turn it off, not turn it on.
- [94:11]
B
And Interesting.
- [94:12]
A
And that the number of men who are physically imposing and might seem like somebody that would be really great to be able to protect the family unit that have done the work to be able to learn to turn that off to the trigger that makes this person likely to be a flash in the pan. You don't want to fuck with me, bro guy, at least non zeroly are also going to have some triggers that will be more sensitive when it comes to interpersonal communication and domestic disputes and things around the house.
- [94:48]
B
Indeed. It's interesting, isn't it, having that kind of temperament, violent temperament and the capacity for physical aggression. It's really a mixed blessing for women. You know, it's great if the guy's gonna protect them, protect the family, but it's not so great because he can potentially turn that against them as well. And so, you know, you get the evaluation of. Of those traits. It can increase attractiveness, like aggression itself, I don't think increases attractiveness. Protectiveness does. Muscularity and the like can increase attraction somewhat. But because it's a mixed blessing, I think women are also interested in the guy's character.
- [95:24]
A
Muscularity seems pretty reliable at improving attractiveness. Yeah.
- [95:27]
B
Yeah.
- [95:27]
A
And it's probably the most easily modifiable thing that guys can do, right?
- [95:32]
B
Yeah. Yeah.
- [95:32]
A
I think. In fact, I think William said that this is exactly the case because he's. He's looking at his incel stuff.
- [95:37]
B
Yeah.
- [95:38]
A
Did you see now I bro signs this. I put the captain of bro signs hat on when Macken came through last time. And I said, I'm pretty sure that I've seen a study that says a woman would lose more attraction if her partner didn't protect her during a physical altercation than if he cheated on her. Her. And then the guys went and replicated it and.
- [96:07]
B
And you were right.
- [96:07]
A
I was right. I was right. I mean, it wasn't my original insight because I found it in a study that I couldn't discover again, but this, the same insight being true. The protectiveness, the ability to protect. In fact, do you know what it is? It was the willingness to protect.
- [96:20]
B
Yes.
- [96:21]
A
Wasn't even the ability to protect.
- [96:22]
B
Yes.
- [96:22]
A
But I suppose willingness to protect is the most important part of protectiveness because you can be the biggest guy in the world, but if you're not prepared to step in between your missus and this potential assailant.
- [96:32]
B
Yeah.
- [96:32]
A
It doesn't mean anything.
- [96:33]
B
You might as well not be exactly, you know. Yeah. Exactly.
- [96:35]
A
I wonder, do you know what it is? I wonder if this would be. This is another new skew that the guys should do.
- [96:39]
B
Yeah.
- [96:40]
A
Is it more or less attractive for a guy who could protect you to not than a guy who couldn't protect you to not.
- [96:49]
B
That's an interesting one.
- [96:51]
A
You know,
- [96:53]
B
but in terms of the character trait, it would be. Be less attractive for the guy who could protect you but doesn't. Right. That shows a worse character. But I guess it does also matter.
- [97:06]
A
I just.
- [97:07]
B
They're not going to do it anyway
- [97:08]
A
to be able to in future.
- [97:09]
B
There is that.
- [97:10]
A
Yeah, yeah. I need to teach him to be able to like be strong enough to be protective or I need to be able to change his character in order for him to use his strength of potential protectiveness.
- [97:21]
B
Yeah, yeah, yeah. But if he's definitely not going to do that, that's going to be very off putting and you might just want the person who is not quite so good at protecting but is willing to do it if they can do it. Fascinating. There's trade offs though, right?
- [97:35]
A
Why is it that women care more about a man's height than women do? Is it plain to this?
- [97:39]
B
I think it probably is. I think it must be. I think it's within a cluster of traits that determine protectiveness and the like muscularity, height, they're all, all part of the same package. And it's interesting, right. That does seem to be really, really high on the list for women. It seems to be very important.
- [97:54]
A
You know why this makes the most sense and it's the probably. Yeah. I would go as far as to say it's the most commonly cited well you bitches Internet kind of rebuttal that guys have around. I think Tinder released as an April Fool's joke about 10 years ago a height filter that people could use. Wouldn't it be funny if we gave you a height filter that's now an actual feature?
- [98:23]
B
It's an actual feature, right?
- [98:24]
A
Yeah. And many women don't need to date or don't want to date men that are under six feet. Especially not men. When you get sort of like five seven, five, six, five five, Very few would. And I had this insight, the tall girl problem. And it was born out of a friend whose, whose sister is 5 foot 2. Sorry, her sister's 5 foot 11. So if she wants to wear heels on her wedding day, she's looking for professional athletes.
- [98:51]
B
Yep.
- [98:51]
A
And they were going around the supermarket and she saw this guy who was like six, five, like tall dude, like you tall guy. And she sort of nudges her sister and says I might go up, I might go up and talk to him. And they round the corner and they say, see him with this 5 foot 2 Latina. A bombshell. And she kicks off at her sister quietly and says, like, this fucking bitch. Like she could date 5 foot 5, 5 foot 6, 5 foot 7. Why'd you have to take a guy that's a foot and a half taller than her? But the point here is, if we're talking about protectiveness as the driver, the fact that your chick is a 52 Latina, not a 5' 11American does not make your height any more or less useful when it comes to protectiveness. I don't need to protect you less just because you're smaller.
- [99:45]
B
Yeah, yeah, yeah. Indeed.
- [99:47]
A
You know. Yeah. And this is why I think you don't see much of a height compensation effect.
- [99:54]
B
Yeah.
- [99:54]
A
Other than, I guess if you're 5 foot 2, you can't really tell the. Like, I don't. Above probably 5, 10. It's all just up there that. It's just like it's over there, you
- [100:04]
B
know, in the clouds. Exactly. Yeah. My cousins. My cousins are quite tall because I'm from a tall family. And I know they were complaining. Often I remember them complaining, female cousins, about guys, taller guys, dating much shorter women. But guess how. Guess how tall my wife is. She's five foot four. So these bloody.
- [100:24]
A
How dare they take the toll, man. All right, sex differences in store talking. What about that?
- [100:29]
B
Women do a lot more of it. Joke. Men do a lot more of it. Men do a lot more of it. I think it's just an example of the fact that men are more proactive. Seeking out mates, seeking out multiple mates. And stalking is the subcategory of that when it gets into extremely inappropriate examples of that. And also, I guess it's not just mate seeking, it's also. So when people get fixated on somebody and both sexes can do that, they can get fixated on somebody.
- [101:02]
A
Sort of limerence type thing.
- [101:04]
B
Yeah, yeah, exactly. Limerence. Yeah. So sort of falling in love. Except that we call it limerence because it's an inappropriate circumstance, I. E. A circumstance where the other person does not reciprocate. Both sexes can do it, but men are more prone to aggression and risk taking and just bad behavior. And so they're more likely to do more of those kind of behaviors in the context of limerence and being fixated on somebody.
- [101:28]
A
Surveillance, surveilling of a partner, checking in. Because I could see two reasons why either side might be doing it. More male parental uncertainty, which we haven't talked about yet, but is super important that no woman has ever given birth to a child and wondered whether it was hers. But many men have Looked at maybe even all men to some degree. In fact, it would be evolutionary useful for you the first time that you look at your kid to be so beautiful. And are those my eyes? Yeah, yeah, I think they're my eyes. But given the fact that you have high male parental uncertainty because you've got concealed ovulation and you don't have the same kind of sort of harem, hermetically sealed sphere when it comes to men and women stalking, I could see a surveillance. Surveillance behavior could be a part of mate guarding totally to try and counteract that. But I could also see how it would be useful for women in order to ensure that their partner doesn't leave them high and dry because there's more of a dependency. Especially if we are going to have a kid or do have a kid. The man doesn't need the woman as much for survival, but the woman doesn't need to check on the man as much to ensure female parental uncertainty.
- [102:50]
B
Yeah, that's exactly right. And both sexes do get jealous. Paternity uncertainty or parental uncertainty is uniquely an issue for guys. But you're absolutely right that there is the danger of desertion for women. And so for different reasons, both sexes have evolved to be jealous and prone to jealousy. And one way that that manifests so jealousy drives mate guardian behavior. And one sex subset of mate guardian behavior is surveilling and just keeping an eye on what the person is up to and are they getting on too well with that good looking next door neighbour or the good looking guy or woman at work. And then if you take that to an extreme, that's where it becomes surveilling behavior.
- [103:31]
A
Isn't it interesting that you have an extreme insight of men about other men and an extreme insight of women about other women. But the failure of cross sex mind reading still occurs even when you add other individuals. So when we're talking about surveillance, jealousy, mate guarding, et cetera, the. I mean William put these stats up recently about how what the percentage is of men who would sleep with a female friend. It's huge. Yeah, it's like 50% of relationships used to be friendships.
- [104:07]
B
Yeah, yeah, yeah.
- [104:09]
A
So that's like 50%.
- [104:11]
B
Yeah.
- [104:11]
A
Right. That's a huge amount. And, and I think when you put all of this together, you end up with a world where inside of a relationship men are trying to explain to women what they see in other men that are around them. And women are trying to explain to men what they see in the other women that are around them. And just because it's not Them talking about themselves doesn't mean that they can explain it. A woman is no better at understanding another man than her own husband. And a man is no better at understanding another woman than his own husband. Wife. In these sort of more subtle, hard to detect motivations and behaviors.
- [104:51]
B
Those data that William was talking about. So, yeah, so, like, a lot of guys would be interested in sleeping with friends that they have. Right. But it's not true in the other direction. Like, fewer. Some women, but fewer of them are particularly interested in sleeping with male friends that they have. But because of the sexual overperception bias, the male friends in question would probably assume otherwise.
- [105:14]
A
Otherwise, what's the sex difference around sexual violence?
- [105:19]
B
Sexual violence? Men are much more likely to do it. And that is just partly. Just an offshoot of the fact that men are more aggressive. More aggressive? Yeah. And the numbers are pretty big. So sexual violence is much more often perpetrated by men than by women. It doesn't only go in the one direction, though, but it is just much more common for men to do it.
- [105:41]
A
Have you got any idea what the numbers are?
- [105:43]
B
I probably do. Let me have a think. Okay. So I do have a few numbers coming to mind, but I'm not actually sure if they're the right numbers. So I'm going to again, do the annoying academic thing.
- [105:53]
A
Directionally correct. Specifically, babe.
- [105:55]
B
Indeed. So directionally correct. And I've got to say that it is a big difference. I think the fixed size might be something like two. So, like two standard deviations between the mean for men and women for the extreme for forms of sexual violence and sexual assault and harassment and the like.
- [106:16]
A
Yeah, yeah, yeah. Another situation where it's kind of hard to talk about evolutionary explanations for bad behavior. Like the worst behavior. Right. Between this and homicide, without sounding like you're excusing. It is natural, but.
- [106:27]
B
Exactly. But again, natural doesn't mean good.
- [106:29]
A
Yeah.
- [106:29]
B
Often, you know, you can explain bad stuff without saying that actually the bad stuff is not good stuff. It's still bad even if it has an evolutionary explanation.
- [106:37]
A
Yeah, yeah, yeah. Analysis is not justification.
- [106:41]
B
Yeah, yeah, exactly.
- [106:43]
A
You know, that's a fucking Hassan Abi quote. That's like a Hassan piker quote.
- [106:47]
B
Is that right?
- [106:47]
A
Yeah, he got canceled. He got canceled for talking about some stuff to do with the right wing.
- [106:50]
B
Yeah.
- [106:51]
A
That is an absolute slam, river of a line analysis.
- [106:53]
B
It is true. Yeah.
- [106:55]
A
But we can see sexual violence if men are able to procreate without having to do any investment. The ultimate form of that is to not even have to ask for consent. As well.
- [107:11]
B
Yeah, yeah, indeed. And you know, it has been argued that the tendency in some men to do that, to take that path, does have evolutionary roots. And I guess really you just have to have two things. You have to have men's greater interest in sexual variety and casual sex coupled with their willingness to use violence in certain, you know, certain situations. So because men are more interested in casual sex, it's going to be not uncommon for a man to want to have sex with a woman who doesn't want to do so. And because men are willing to use violence sometimes to get what they want, every now and then you are going to have that situation where those factors add up and the man is going to try to find. Force the woman to have sex. It's not as found in our species. Males and many species try to coerce women, females rather into sex. It happens in our species. It's also been argued though, that because preserving female choice is so important across the animal kingdom, including in our own species, so important to women, that that helps explain why sexual coercion and rape is so upsetting to women. You know, it's not. We haven't just been socialized for it to be upsetting to women. It's very, very deep in a female's nature to be upset by it because it compromises female choice.
- [108:34]
A
Oh, that's interesting. Yeah, that's interesting because not only is it fucking heinous, but you know that because somebody, because this male committed that behavior, they've had to disregard the entire female wide value that is supposed to be universally protected.
- [109:02]
B
Well, right. Well, I mean, she's evolved this tendency to be choosier about her mates than men have. And she's got these mate choice criteria. And that's because she can have fewer offspring and therefore each offspring counts for more. So she's got to be wiser in every mating decision that she makes. And this other male has come along and has just taken that away from her, taken that choice away from her. Has gone against, she's evolved to be choosy and gone against that.
- [109:34]
A
I think that the inability of men to fully understand what fear of sexual violence must feel like.
- [109:43]
B
Yeah.
- [109:45]
A
Is one of the reasons why any guy who's seemingly sort of flippant or callous about any type of male female aggression, even non sexual violence.
- [109:57]
B
Yeah, yeah.
- [109:58]
A
Is treated with a very strong antibody response from, from women.
- [110:04]
B
Indeed. Yeah. And guys, do, you know, guys, the idea of going to prison and being raped in prison obviously is, is terrifying to a lot of guys. So they do get it to some degree. And I guess particularly when it comes to the sort of lower level stuff. I think in Bus's Bad Men book he talks about research suggesting that men often will underestimate just how upsetting it is to women to be sexually harassed and to have stuff done to them against their will. And that's another very good example of a. And a very important example of a failure across sex mind reading where the guy just doesn't really appreciate just quite how upsetting it is for that to happen. Because if it were to happen in reverse, if it were to happen to him, he might not like it, but he on average is not going to be quite so upset by him.
- [110:48]
A
It's interesting that people who deny sex differences seem to sort of not want to argue for parity, that if women weren't so held back, they'd want to commit just as much violent crime as men do.
- [110:59]
B
Indeed. Yeah. Indeed.
- [111:00]
A
There's a directionality to the way that this analysis happens.
- [111:05]
B
Yeah.
- [111:06]
A
Why is it not that we've got 50, 50 in terms of homicides like that we should do. Women should be free to commit just as many killings as they want to.
- [111:14]
B
Yeah. And they've just been kept down. The fact that they're not doing it.
- [111:17]
A
The patriarchy. The damn patriarchy.
- [111:19]
B
And I guess the thing is that they. And we all would want it all to come down. And it's a good example of how equality is not necessarily a good thing in itself. So men are more aggressive than women. The solution to that is so we want to kind of reduce male violence. And in the process of doing that, we're going to reduce the size of the sex difference. And that's a very good thing to do. But the reason it's a good thing to do is not because there's anything inherently wrong with the sex difference. It's because violence is bad. It's not because the sex difference is bad. It's because the violence is bad. And we know that because another way to get rid of that sex difference in violence would be to increase the female level of violence. And that would be big thumbs down on that. Right. That is going to make the world a worse place rather than a better place. Point is. Yeah. Equality is not a good thing in itself.
- [112:10]
A
Yeah, yeah, yeah, yeah.
- [112:11]
B
Okay.
- [112:12]
A
What about the differences in parenting?
- [112:13]
B
Differences in parenting? That's quite a controversial one actually. That's one of the ones that people like least. The aggression sex difference. No worries about the parenting sex difference. People aren't so keen on. And that refers to the fact that. That in every culture, again, where we have good data, women do more of the direct parenting than men do and they invest more in the young, they do more parental care. Men in every culture do more than your average male chimpanzee or male walrus, but they do less than women in every single culture. And it doesn't seem to just be because men are forcing women to do it. There do seem to be average differences in terms of parental inclinations with women being more interested in doing it than men are on average. And yeah, I guess the reason that it's controversial is that there's a concern that people are saying, making up an excuse why you should do it. So guys are using it as an excuse. It's just natural that you should want to be changing the nappies and doing these things that coincidentally, I would rather not have to do. So that I think is the concern. But in a way it's ironic. So the fact that people consider it. It to be kind of an insult to say that on average women are more interested in parenting than men implies a negative valuation of parenting or doing more of the parenting. Because if it didn't imply a negative valuation of that, it would not be an insult to say that women on average isn't.
- [113:41]
A
It's been one of my most. One of the best ideas I think I've come up with over the last couple of years, which was the soft signal of male expectations.
- [113:49]
B
Yeah, yeah, yeah. I think you mentioned that when we met the first time. Right? Yeah, yeah. The soft bigotry of male expectations.
- [113:55]
A
Softbeatriven.
- [113:56]
B
It's like as if we treat the male standard, whatever men do, that's the standard of what is right. And if women do it less, that's a bad thing and we should make them more like males, but not so much the reverse. Yeah. And it is very ironic because it's really misogynistic worldview. It is really, isn't it? It is. It is. And so if we're taking a negative valuation of parenting, which is what we are implicitly doing, if we say that it's an insult to say women are more parental where implicitly. And if it is actually true that women on average are more parental by nature, then we're taking a negative valuation of a more female typical trait. And that is really sexist.
- [114:35]
A
Yeah, yeah. What's the kibbutz experiment?
- [114:38]
B
The kibbutz experiment. So there were these kibbutzim that they had in Israel. So these were these communes, like highly egalitarian communes, where they wanted to get rid of all traditional kind of structures, including traditional little male, female ways where the woman is expected to do all of the childcare and the guy is out in the public doing the public stuff. She's at home doing the private stuff. So what they did was they would get all the kids and they would house them in communal houses. And then they would have dedicated adults within the group who would be the. Primarily in charge of looking after all the kids. So the kids weren't living under. Under the roof of their biological parents. They didn't think the idea was everyone should care for everyone rather than having this traditional, what they saw as bourgeois approach where people are specifically interested in their own biological children. They wanted to get rid of that. They did manage to make it work for a while, but what happened was that the parents hated it. Basically. The parents hated not having their own kids living with them under their roof. And they agitated and complained about it. And eventually it broke down. And the interesting thing was that although both parents hated it, most of the mothers particularly hated it. And a lot of the agitation came from the mothers more than the fathers. And it's a great example, a great case study, because we often hear that women are placed in the primary caregiver role, role by men. That might have kind of forced them into that role. But here was a case where actually the women in particular were rebelling against the male leaders to try to put themselves into that role instead. So it's another example of a very common phenomenon where you see certain behaviors and certain aspects of human nature that emerge and persist despite culture, rather than because of culture. Culture's pushing the opposite side of the.
- [116:42]
A
Actively going against it.
- [116:42]
B
It's a. Exactly.
- [116:43]
A
Yeah, exactly. Yeah. I saw this really heartbreaking video of a woman on TikTok. She was at work in a cubicle, looked like a sort of normal office cubicle. And she had a screen up of maybe the daycare that her kid went to. And she was seeing. Watching her kid say its first words or take its first steps. And it was just one of those ones with a caption over it that said, like me being devastated that I'm at work while my kid is going through one of the most meaningful experiences at the start of its life. And I'm missing it.
- [117:21]
B
It's tough, right? There's a real. That's the work family, you know, clashing roles that both sexes do experience. But it does seem to be still a bigger deal to women than men.
- [117:33]
A
Yeah, it's certainly not something that people are happy to talk about maternity leave and the lack of maternity leave as being kind of barbaric. And I. I mean, the UK gives nine months, which is still not enough, but feels at least remotely humane.
- [117:47]
B
Yeah.
- [117:49]
A
The US is basically. Once you're out of the hospital, you're back to work.
- [117:53]
B
Yeah.
- [117:55]
A
But very few people. I think it's not a big cultural conversation around what is missed by either the need to go back to work to keep yourself financially stable or the desire to go back to work because of expectations that have been adjusted on women about where their value comes from. This soft bigotry thing. Again, I don't want to be just a mom, but by being not just a mum, I'm also missing out on a lot of the joys of motherhood. It's kind of hard to win that situation. Maybe you don't want to. A good outcome there.
- [118:30]
B
Yeah. And people in general, I mean, in a way there are these kind of trade offs for everybody always. And. And choosing one option always does mean not choosing another one. I know that a lot of people solve that problem to some degree to the extent that it is solvable. A lot of women do by taking some time off, you know, more time off. Taking a career break, in other words, when the kids are young, but then particularly when they go to school, then, you know, getting back on the career. Career horse.
- [118:59]
A
Yeah. What about differences between men and women in sexual jealousy?
- [119:02]
B
Jealousy, that's an interesting one. So both are prone to it, like I mentioned, but for the reasons that you mentioned already, men, men's jealousy is more focused than women's on sex. So a sexual infidelity, like if you ask men which would upset you more, your partner who you love, going off and sleeping with somebody else or just forming a close emotional bond with somebody else, the both of those are upsetting to most men, but men are more likely to sleep. Say that the sex is more upsetting than just the bond. And you pose the same question to women. And again, both of them are upsetting to the vast majority of women, but they're more likely to say that the emotional bond, they're sort of falling in love, maybe falling in love with the other person, that. That's more upsetting than just sex per se. It's interesting. Right. And it comes out of the fact that men had this problem of paternity uncertainty. Like you say, no man in the history of the species has ever. No woman around in the history of the species ever given birth and thought, now how do I know that this is my kid and not some other woman's kid. Whereas for most men more than likely it is their own kid. But there is always some non zero chance that actually it's not that it's the good looking next door neighbour's kid instead. So yeah, that's why sex is a more important issue for men than women. Women are more likely to be left holding the baby and that is not good for their fitness because it's going to reduce the time before they can have another kid and just make things a lot more difficult for them. And so it's obviously not great if their partner sort of sleeps with somebody else. It's not great. They'd be very, very upset about it. Very often it destroys the relationship. But it's even worse for most women if the partner gets emotionally involved with somebody else because they're then whether they want the relationship to end or not, it's gonna end cause they're gonna leave. Very likely going to leave and set up shop with the other woman.
- [121:03]
A
I have an example that I heard about from a while ago that A friend was on 23andMe or Ancestry.com and one day in their 30s got an email notification saying you've got a new half sister, right? And she says how the fuck have I got a new half sister? What it turns out was that 32 years ago the dad had had a one night stand affair. That kid had never met the father, never been involved again. But three decades later this situation unfolds and obviously awful, awful to try and live through. But I would have been fascinated to have done a study to work out about. What happens to sexual jealousy and intimacy. Jealousy and the fear of resource provisioning needing to be split. When you've gone past all of those things because you have this three decade assuming that there's not been more infidelity, this three decade example of someone committing to the family and raising the kids and doing the rest of this stuff. And also the person that would have been the dependent is no longer in need of any of the provisioning. You understand what I'm getting at to separate out all of the typical areas. Trust, infidelity, all of those things. Obviously horrible, but kind of fascinating too.
- [122:36]
B
It is really fascinating. And I wonder if this could be an example where proximate and ultimate, thinking about the proximate and ultimate might solve the mystery. Because it's possible that because we don't necessarily think about, we don't necessarily think it through, we're not necessarily thinking, well I'm going to lose this partner, he's going to Fall in love with her and he's going to go away. And then I've got this baby and I'm going to have no one to help me with it. That's the evolutionary rationale. But it could just be a gut reaction, like he's getting close to somebody else. I hate that. I feel jealous, I feel bad about it. And so that could kick him just as strongly 30 years down the line when it doesn't matter in anyway. Like you say, trust issues and those kind of things are gonna kick in, could kick him just as strong. Even though evolutionarily the circumstances, it doesn't matter anymore. The gut reaction that evolved might not discriminate those details.
- [123:30]
A
What do we know about sex differences in personality?
- [123:33]
B
Well, there are some and they're pretty consistent. They're not huge. Two of them are bigger than the rest. Now, if you're thinking about the big five personality traits, so the Ocean acronym. Right. So openness to experience, neuroticism, extroversion, agreeableness and conscientiousness. I got that in the wrong order. That wasn't Ocean, but those are the five. So the two sex differences that are largest and most consistent are the sex difference in neuroticism, which is proneness to negative emotions like depression and anxiety plus emotional vol. Volatility. So ups and downs. And that is about a medium effect size. So I guess it's usually estimated between about 0.2 and 0.5 standard deviation between men and women. There's that one. And then the other consistent one is the sex difference in agreeableness. And women on average score higher. Again, it's not a massive difference, heaps of overlap, but again, it's 0.2 to 0.5. I would say it's a medium small to medium sex difference as well. There are some sex differences in the other three big five traits. Often, not always. You sometimes find that women score a bit higher in conscientiousness, but not always. Some studies don't find that. Extraversion, on average, women slightly higher on extroversion, but again, not always. And it's a smaller difference if it is women. And then what's the other one? Conscientious openness. Yeah, openness slightly higher for women as well. All no difference.
- [125:13]
A
What's the explanation for why those would be the case?
- [125:16]
B
Well, I don't think we know for sure, but my best guess. So then neuroticism, sex difference. So that's proneness to things like anxiety and depression. And I think women. There's a general trend where women Seem to be more self protective than men. Which is kind of the flip side of the. The fact that men take greater risks than women, they're more risk taking. I think that that evolved because that is about trying to propel yourself up the status hierarchy. You've got to take risks in order to do so. And men have evolved to do that more than women because they have a higher maximum offspring number. But yeah, the flip side of risk taking is to be more self protective. Part of that is to be more prone to anxiety. Anxiety. The function of anxiety is to. It's the same as the function of the turtle shed shell. It's to protect yourself. It's about protection. So I think that's why women are more neurotic. Now the agreeableness sex difference. So women on average are more agreeable. I don't have quite as strong an idea about that. I do think that. Well, I guess it could be the flip side of the fact that men are sort of more. More aggressive, more pushy and that evolved like we discussed to, to try, try to again get up the status hierarchy, beat rival males to go up in the world and achieve status and resources. Women have evolved to do less of that. And one manifestation of that is the fact that they're more agreeable, more friendly, more compassionate and just the way that women have evolved to form social bonds, it does tend to have a higher level of compassion and understanding the other person person that seems to be more common in women than men.
- [126:55]
A
What about the people versus things divide?
- [126:57]
B
So that's an interesting one, right? That is a bigger difference. That's actually quite a big difference. It's one of the bigger psychological sex differences and the effect size there is like one standard deviation or even a bit more when it comes to people versus things. Very, very consistent. I think there's a good case that it is not just due to socialization. So one thing is that like I mentioned earlier, it has persisted for as long as we've been measuring it. Very, very consistent. Even when the culture is trying to push against it and get women more interested in things. Related professions traditionally male professions seems to be related as we also mentioned, seems to be related to prenatal hormonal exposure. And one thing I haven't mentioned already is that it's also very very cross culturally consistent. So there was one study that had about 200,000 people in it and found that sex difference in correct related interests founded in 53 out of 53 nations. And another one had half a million people and founded an 80 out of 80 nations. And that level, it's amazing, right? That level of cross cultural uniformity, you just hardly ever find it in the social sciences, but you do find it for that difference.
- [128:05]
A
And this has been around for 100 years.
- [128:07]
B
Yep. Yeah.
- [128:08]
A
It was first documented in 1911.
- [128:10]
B
Yeah, yeah, that's right. Yeah. That's when they first documented it. And it's been consistent ever since. It's one of the biggest differences. Differences. And I always find that pretty interesting really. Because the kind of careers that we have today are evolutionarily novel. So you might not necessarily expect that to be one of the biggest sex differences. You know, interest in careers that just haven't existed throughout the vast majority of evolutionary history for our species. But it's there and very consistent.
- [128:34]
A
And there's been some deliberate effects, attempts to try and close it as well.
- [128:38]
B
Indeed. And they're ongoing. And it just doesn't seem to. Doesn't seem to budge really. Yeah. Interesting.
- [128:45]
A
The soft bigotry of male expectations happens with get more women into STEM as well.
- [128:50]
B
Yeah, indeed. As opposed to get more men into traditional female dominant. Exactly, exactly. But you know Richard Reeves who has been on the show. Right. And that he's. He's trying to get more men into those kind of professions.
- [129:03]
A
He's trying to do it. But again, I think the reason that there is a publicly lauded push toward getting more women into STEM is because of that soft bigotry.
- [129:16]
B
Agreed.
- [129:16]
A
And if you look. I'm gonna guess that if you look at the gender equality paradox, you're going to find that in more gender equal nations, fewer women end up going into things based roles and more men go into things based roles.
- [129:32]
B
That is exactly right. Yeah. And just the interesting in it gets bigger in those cultures as well.
- [129:37]
A
Regardless of what you do. That's an interesting one to have to separate out what jobs are available to you and can you get from what ones are you interested in?
- [129:44]
B
Yep, exactly. And both expand. And it is interesting. Now I think that you're right that it does reflect the soft bigotry of male expectations. I think people who want to close those gaps also will typically point out that those kinds of professions pay more as well. And that's another reason to try to close the gap.
- [130:03]
A
But that doesn't change the interest.
- [130:04]
B
It doesn't change the interest.
- [130:06]
A
People are interested in things because I, I went to university and did business.
- [130:10]
B
Yeah.
- [130:11]
A
Because I thought I could get a job in it. So I became interested. But it was a very transactional type of Interesting. Yeah. So. Yeah. How many people develop an interest in a thing because it's functionally useful for them to acquire resources in it. I, you know, it might depend.
- [130:31]
B
I would say that in a pretty wealthy society that more men than women do that now. And in poorer societies I think it's more common for everybody to do that. You know, some poorer societies you just think, well, I would love to do whatever it is impressionistic dancing or whatever.
- [130:46]
A
But you get some in, in high inequality and high poverty environments you get some really interesting outcomes. You've seen Candace Blake's work on the female beautification?
- [130:56]
B
I have, yeah. Remind me, remind me the details.
- [130:58]
A
So they analyzed it was either Instagram posts or tweets wheats and correlated them with the level of income inequality in the local ecology. And in areas with higher income inequality, women did more self sexualization and more stratification. And supposedly the proposed mechanism for that is when you see not only how high you could climb but how low you could fall, you try to maximize your ability to be assisted in being dragged out of that from a resource provisioning perspective.
- [131:24]
B
It's cool research there, right?
- [131:25]
A
Yeah, it's, it's really cool. But basically it's just when material restrictions are in place, stuff gets warped and squirrely because people are concerned about survival. I mean, you've seen the environmental security hypothesis as well about men are more attracted to bigger women in times of poor economy and more attracted to skinnier women in times of bad. In times of good economy.
- [131:54]
B
Yeah, it's interesting. And that does seem to be pretty good data on that. I am not 100% persuaded are the evolutionary arguments for it though?
- [132:02]
A
You could survive a famine, there's a famine imminent. You couldn't survive a famine. But it doesn't matter because we got loads of food.
- [132:06]
B
Indeed. And I mean it does make sense. The logic there does make sense. But I mean, is it the case that for a long enough fraction of human evolutionary history we had feasts and famines? I'm sure we did have that. But were the feast periods big enough that people were actually getting bacon? I mean, my impression is that that hunter gatherers, they just didn't really get big enough that they would.
- [132:30]
A
Selection would have been very, very, very rare.
- [132:32]
B
Exactly.
- [132:32]
A
It would have been almost impossible before what, 13,000 years ago. It would have been almost exactly impossible, definitionally, because you could only eat what you could carry.
- [132:44]
B
Exactly.
- [132:44]
A
There was no surplus at all. That's interesting.
- [132:47]
B
So I sort of feel like today
- [132:49]
A
we can fucking grill.
- [132:50]
B
We can talk about that. Yeah, because he's a fan of that
- [132:52]
A
Right, yeah, yeah, he is. Well, he likes the sort of behavioral ecology approach to things. He likes humans as plants as well as humans as animals. So we grow toward the sun. And how is the local ecology? Imposing and warping. But definitely the self sexualization in high income inequality makes sense.
- [133:12]
B
Yeah. And I do agree with the general principle that we've evolved to respond to the psychology. I'm just not sure in that case it could have evolved because of there weren't fatter people around the place for long enough.
- [133:25]
A
What about cognitive abilities? Is there a sense
- [133:31]
B
if anything is. I would say that's probably the most controversial topic that I deal with in the book.
- [133:37]
A
Let's bury it two hours into the episode.
- [133:41]
B
So there are some, I guess few things to say to avoid. Try to avoid getting cancel is first of all that there are no sex differences in the cognitive ability that matters most to most people, which is IQ or general cognitive ability. There is basically zero sex difference in the average there. Now people, when you say that, some people will say, but that's because IQ tests have deliberately been constructed to create equal averages. And that is true. Some of them have. Some of them have. But there are some IQ tests, some
- [134:13]
A
of them offset the sex difference difference.
- [134:15]
B
Well, that's the theory. And so some of them have been deliberately created that way, but some haven't. But even those ones that haven't been created specifically to give the same outcome and balancing spatial versus verbal and that kind of thing, even when they haven't, they give basically the same averages with representative samples of people. Now sometimes you'll get some studies that will have males doing slightly better on average. But I'm persuaded by the argument that that is because the very low IQ males are more likely to fall off the map, fall through the cracks and kind of disappear and not end up on the samples than the low IQ women bringing down the female average.
- [134:58]
A
Because we do have a higher variance.
- [135:00]
B
Yeah, right, yeah, yeah, yeah. In cognitive abilities there's higher variance. Yeah, average is the same. The variance is slightly greater in men than in women.
- [135:08]
A
More male geniuses and more male retards.
- [135:11]
B
That is exactly right. But important to note that that's quite a small effect and that is this is the controversial area and that's maybe the most controversial claim within that controversial area. So I always like to follow that up by saying so people hate that because it's a cognitive advantage that gives an advantage to guys. But there are also other cognitive ability sex differences that give the advantage to women. So women on average are better verbally that is one. And another one is that among the minority people who are really, really gifted at maths, the women are more likely than the men to also be gifted verbally, so they're more likely to be a double threat.
- [135:53]
A
That's cool.
- [135:56]
B
So no average differences in iq, where you do find differences, they're just as likely to favor women as men, some of them. In some cases, men are slightly better. Spatial abilities, that's an example. Verbal abilities, though, women tend to be somewhat better. And then most of the differences are small, so they're smaller than the personality differences, they're much smaller than the differences in interests. So when it comes to cognitive abilities, we're much more alike than different. But having said all that, there are these average differences in these specific abilities. And that, like it or not, that just is the fact of the matter. And that's been measured for 100 years as well. There's tons and tons of data on it, typically found across cultures. Very likely, I think, to be partly innate. You know, it's shaped by culture as well. You can minimize it and I guess also in principle, you could increase it as well. But yeah, I would be surprised if it's just due to socialisation.
- [136:56]
A
What about physical health?
- [136:57]
B
Physical health. There are some definite sex differences there. One of them, and the one that's probably best known, is that men are more prone to cardiovascular disease. They're women more prone to heart attacks, in particular, at least among, like in 50s and 60s, until very old age. Men are more prone to those. Women are more prone to immune system disorders, they're more prone as well to pain disorders. Men are more prone to most forms of cancer, other than sort of reproductive cancers that only strike one sex or the other. Men are somewhat more prone to cancers as well. And actually one of the big ones is that men die younger on average than men in the vast majority of cultures, including even most cultures where women have high rates of death during childbirth. So we drew the short straw there.
- [137:50]
A
Eunuchs in the Korean Chosun dynasty lived longer than intact males of identical social standing, demonstrating that testosterone has a direct biological cost to male lifespan.
- [138:01]
B
That is very true. So I touch on that in the book In A Billion Years of Sex Differences. I write about how actually most people probably don't know this, but we do actually already have an intervention that we could in principle do, which would completely obliterate the. Be the average difference in lifespan between men and women and would extend men's lifespan. And that is castration. It's gotta be castration before you Hit puberty though. So, you know, sadly enough, if anyone wants to take that approach, if you've already hit puberty, it's too late. But yeah, the fact that it would work is, it's interesting. Does show that it's testosterone that is making us bigger, stronger, more aggressive, but also shortening our lifespan as well.
- [138:39]
A
If male mortality rates were lowered to female rates, Randy Nesse, who did the evolutionary medicine studies, calculated we would save more years of life than if we cured cancer. If male mortality were at female rates, we would save more years of life than if we cured cancer.
- [138:55]
B
Yeah. So we're so used to it, so used to the fact that men die younger that we don't really think about it, I think. But then when you do think about it, yeah, you find that that is just a massive, massive difference.
- [139:06]
A
And then we've got 88% of Darwin Award winners, which are people who die through spectacular self inflicted stupidity, are men. But 90% of Carnegie Hero awards, which are given to people who risk someone's in order to save a stranger, also go to men. So the risk sort of cuts both ways. It's almost exactly the same. 88% of people who die through stupid self inflicted ways are guys. And 90% of people who risked one's life to save a stranger are also guys.
- [139:33]
B
Yeah. So that is the trade off there of risk taking. Right. In fact, almost by definition, taking risks can pay off big time, but can also kill you winners and losers. Yeah, exactly. And because men do more of that risk taking, I mean that's one of the reasons, I think that's that you get more males than females will start a business that does really, really well and people focus on that and they think it's unfair.
- [139:56]
A
I'm gonna guess more will go bankrupt too.
- [139:58]
B
Exactly, exactly. Right, yeah. They're more likely to go in both directions. So they're more likely to succeed because they take bigger risks, More likely to fail because they take bigger risks. Some people when they hear about that, they think, well, we should encourage women to take bigger risks. But the problem is that they are then to the extent that they do that, they're opening themselves up not only to greater chances of success, but also to greater chances of failure.
- [140:19]
A
Risk doesn't just cut one way.
- [140:20]
B
Totally. Exactly. So my solution there I think would be just tell everybody all the facts. Tell men and women all the facts. This approach to life, this risky approach cuts both ways. You could go up, you could go down, do what you want with that knowledge. That's my approach to just a Lot of gender gaps in general. Right. So like workplace gender gaps. Tell people all the facts, try to get rid of, I mean, just do everything we can to get rid of bias and barriers. But then having done that, respect people's choices about their own lives and how they want to live them and what careers they want to do.
- [140:54]
A
What's really interesting about that is if you try to compartmentalize the information that people see and you don't give them full access to the information, what you end up with is actually a world in which there's more likely to be resentfulness. This and you need to do more compensation on the back end because people have made decisions under imperfect information.
- [141:21]
B
Yep, yep, that's exactly right. And some of the steps I think that people take to try to balance out gender gaps in the workplace, I think can have exactly that effect. Creating resentment. There's one of the dangers, really, I think, of overstating the extent to which gender gang gaps in occupations are due to bias and barriers. I do think it's absolutely essential to look at the extent to which they are due to those facts. But I think we just to bias and barriers. I think we also, though, need to look at the extent to which they're due to preferences as well. Because if we don't, first of all, if we say any kind of gaps that you see are products of discrimination, first of all, it's going to create unnecessary resentment because you're going to say, look at these gaps. That's because of men mistreating women. Second, it's going to lead to costly interventions to try to eliminate the gaps. And those interventions are probably not going to work because they're targeting things that are not the causes, the primary causes of the gaps in the first place. Then what happens is because they don't work, we start doing more and more coercive things to try to eliminate the gaps. Yeah, in some cases we do anti male discrimination kind of inadvertently just trying to eliminate the gaps. We get a bit more coercive and end up, instead of getting rid of discrimination, which is what I think we should do, we end up reversing the direction of discrimination, which I think is just creating. It's not undoing past injustices, it is just adding to the additional injustices. Exactly. And reverse ones. And then that can create a bottom backlash among guys. And then also if we exaggerate the extent to which discrimination is behind those gender gaps, like in stem, for instance, we say, you have these gaps in stem, more men than women go into it and it's just because STEM is just riddled with sexism. It's a horrible, horrible hotbed of sexism that's going to put a lot of women off, girls and women off who might otherwise go into it. So ironically, the same effort to try to fight it could actually be, you know, create the reverse.
- [143:34]
A
You touched on it earlier on. What about differences in mental health?
- [143:38]
B
Mental health. So there's the neuroticism sex difference. First of all, women are more prone to depression and anxiety, just sort of day to day depression and anxiety rather than clinical levels of it. But at the extreme of that distribution they are also more prone to clinical depression and clinical anxiety disorders. Men are slightly more prone to schizophrenia. Men are much more prone to like antisocial personality disorder, sociopathy, psychopathy, more likely to be psychopaths. What else is there? I'll tell you one that where you don't find a sex difference is bipolar disorder. That is, I'd say in the book that that's the least sexist disorder on record because it's basically this same across cultures. It's about the same frequency of both sexes.
- [144:26]
A
What's your explanation for why we would have these differences in mental health?
- [144:31]
B
Well, with the depression and anxiety, I think that's just a side effect of the neuroticism sex difference. So at lower levels it's adaptive for women to be girls as well, but especially women to be somewhat more anxiety prone because they protect themselves more and they're not taking risks in a way that is more adaptive for males because of their higher maximum offspring number. So it's adaptive at that level. But I think that because you have a distribution it means that inevitably some people are going to be the extreme of that distribution. I don't think it's actually adaptive out there. So I don't accept adaptive explanations for clinical depression or clinical levels of anxiety depression disorders. I think that that is a sort of non adaptive or actually maladaptive, often byproduct of spandrel type thing. Kind of a spandrel. Yeah. So just a side effect. Exactly of differences that closer to the mean are adaptive. The schizophrenia difference. I don't have a theory about why that is and I don't think that there is a theory yet about why that is more common among men than women. Some that I didn't mention actually autism is more common among boys and girls. ADHD is more common among boys and girls as well. So yeah, adhd. I think that again that's just a sort of offshoot of the fact that boys are kind of more active on average than girls and sort of less attentive and more likely to get distracted and running around the place. And it's not a problem. And the usual. I mean, it might be irritating for parents and teachers, but it's not a big problem in the normal range. But at the extremes, it is quite a problem. And it's a problem more often suffered by males than females as an offshoot of the differences at the mean.
- [146:22]
A
After going through all of this, doing all of the research, obviously you've been deep in this for a long time and then doing the book, what happens or what's your fear when people don't respect sex differences or they deny them? What's the sort of world that we live in if that happens?
- [146:40]
B
It's a good question, and I think it's a particularly good question because we're always focusing on the dangers of exaggerating sex differences and moralising sex differences. And I think there are lots of problems with doing that and we need to be careful not to do it. But where I think I disagree with a lot of folks is that I think that there are also problems with doing the reverse. I think there are also problems with minimising sex differences and denying them. So one thing is that gender, just as in exactly the same way that some people who exaggerate and moralise sex differences, they try to push people into traditional gender roles, people who deny the differences or massively minimize them, they're in danger of trying to push people out of gender roles. So kind of replacing one gender straitjacket with another unisex gender straight jacket, or like a maybe reversed gender role, reversed straitjacket. And then we've actually touched on another the big problems, I think, with minimizing the differences, which is the fact that trying to explain gender gaps in society, like occupational gender gaps, there's just a whole host of problems with doing that that we discussed. Other problems with minimizing sex differences is that there are certain physical health problems and mental health problems. So not only do they the frequency of different problems differ between the sexes, sometimes the symptoms differ as well. They present differently. So, like cardiovascular problems present differently for women than men, women are more likely than men to have shortness of breath as a symptom, rather than sort of shooting pains down the arms and the other kind of classic problems like that. And if you don't focus on sex differences, you might be more likely to overlook the symptoms of heart attacks in women. Traditionally, doctors and people themselves have overlooked it for that reason, because They've underestimated the sex differences. Mental health wise, same deal. So even though autism is more common among boys than girls, there is a strong case that it's under diagnosed in girls. And part of the reason for that is that it presents somewhat differently in girls. It's less likely, for instance, to involve repetitive behavior behaviors. So people might not know if they're not aware of that sex difference, they might overlook it in girls. And that means girls won't get the help that they need. And yeah, likewise with social problems. If we're looking at social problems like intimate partner abuse, if we assume that all intimate partner abuse only goes in one direction, like male to female, then we're going to to underestimate the center, which sometimes goes in the, in the other direction.
- [149:20]
A
Yeah, the vast majority of it is bi directional, right?
- [149:24]
B
At low levels it is, yeah, sort of low levels. Verbal abuse, pushing and shoving. And actually in the west there's even some data suggesting that like verbal abuse might be more common, women toward men. Other cultures that's not the case and it's more likely men to women. And when it comes to severe.
- [149:43]
A
Damn. Gender equality paradox.
- [149:45]
B
Indeed. When it comes to severe aggression, though even in the west, men do predominate, but you know, it's not a hundred percent.
- [149:54]
A
And what are the harms of exaggerating sex differences?
- [149:57]
B
So one of them is trying to push people into traditional gender roles. And like if you just let people do what they want, probably a majority are going to kind of gravitate in the direction, in traditional directions. But not everyone does because we don't have massive, massive sex differences, somewhat modest sex differences. There are always going to be some folks who are not going to want to go into the traditional directions. And my view, my let people be themselves view would say, well that's fine, just let them, let them be themselves, it doesn't matter. But if you exaggerate and moralize sex differences, you're unlikely to think that you're going to think, well no, no, this is the way of nature. Any exceptions to the rule, that is by definition a problem and we need to push people into those roles. What else other problems with exaggeration differences? If you exaggerate the frequency of cardiovascular health problems, you will say, well, you find them in men, not women. So that's another reason that you might overlook them in women. Just because you just. It doesn't occur to you that, okay, she's got these symptoms, what would that be? Well, it's not going to be cardiovascular problems because those are men's. Problems. Problems get the same thing with mental health problems. If you're really fixated on the fact that depression, for instance, is more common among women than men, you might overlook it in men because you're exaggerating the size of the sex difference. And a significant minority of people who suffer depression are men. About a third of cases are guys. So if you exaggerate that difference, you might not be on the lookout for them. And so I didn't. Disorders as well. And social problems. Yeah. So social problems like interpersonal violence, sexual harassment, if you exaggerate the extent of those, you are more likely to focus on just the cases where men are doing it to women. And those are the majority of the cases. But there are cases. The majority of extreme cases anyway. But you do find the reverse, and the reverse is a problem as well. And it's a problem, though, that we overlook if we exaggerate those sexual differences. There's an irony there, though, which is that the sex difference and sexual harassment, sex difference and interpersonal intimate partner abuse, the people who are most likely to exaggerate that and say it's all men tend to be gender role progressives. So people who generally are trying to minimize and deny sex differences, in those cases, they actually, funnily enough, flip to the reverse and adhere to them and in fact, just reverse it and massively exaggerate those differences.
- [152:33]
A
Fascinating. Steve, you're the best. I appreciate you, man. You've done a wonderful job with this book. Everyone should go and buy it. Billion years of sex differences. What else? What else do you want to plug?
- [152:40]
B
Could I plug my substack? So that's the thing I'm most excited about.
- [152:44]
A
Nurtured. Nurtured Nietzsche newsletter. Dude, I'm a Steve Stuart Williams. Stan, bro. I mean, the AP one just said the universe is in the five books that everybody needs to read from. My first reading list, had this one have been out, it would have been in the same second one. Thank you. Yeah, your substack rules and everyone should go and check it out. I love it. My favorite thing that you do is the link fest breakdowns. Once a month you just send like 40 or 50 different studies or insights that you found. You're the best, man. I really appreciate you. Thank you so much for coming.
- [153:14]
B
Thank you, Chris. Thanks very much for making this happen. This is great.
- [153:17]
A
I got you. All right, goodbye, everyone.
- [153:19]
B
Later, folks.
- [153:20]
A
Dude. Yes.
- [153:22]
B
All right.
- [153:23]
A
Nailed it. Nailed it. Nailed it. Fucking awesome.