Modern Wisdom - The Uncomfortable Science Of Sex Differences - Steve Stewart-Williams - #1120

Starting point is 00:00:00 Do you think that you could have published this book six years ago? I think that I could have, but it would have been less wise move. I think it would have gone down a lot worse six years ago. Things are kind of cooled off a little bit, I think. Why is talking about sex differences so controversial? 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.

Starting point is 00:00:26 They are often differences in preferences rather than cognitive ability. 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 sort of 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 favorite examples of this, is from

Starting point is 00:00:58 scientist by the name of Gustave Lebon, 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 is, I guess, not surprising. They're 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 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.

Starting point is 00:01:36 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. Yeah, I suppose the history of science is to sex differences, what the Nazi party is to behavioral genetics. Right, right, exactly. Yeah. Yeah. And I do think that science is the solution to the early sexism rather than a continuation of it. Yeah, that's a great way to put it. All right. Why is it important to study sex differences then? Why should anybody care? 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. It's the most. It's the best. Dude, me and you fell in love with the same buck, the moral animal. Right. It changed my life. It shaped the rest of my career. I think it's deeply fascinating.

Starting point is 00:02:30 And yeah, I remember when I read that book, that's when I fell in love with evolutionary psychology and in particular I 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. That is why it looks that way.

Starting point is 00:02:53 That is why people are different in that way. Exactly. It all made sense. It was clear that it was true. And yeah, just sort of instant insight. And 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 dot, dot, dot, dot. 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.

Starting point is 00:03:35 Yeah. You can't have an interest in something which is fundamental and fascinating and really important. Yeah. 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

Starting point is 00:03:55 to what we want. Fascinating. Yeah, it is. Yeah, so I do, I agree with that. And I think, yeah, sorry, I just, I just meant blank. What was it going to say about that? Just why is it important to study sex? Oh, yeah, why is important.

Starting point is 00:04:12 Yeah, so 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 staring 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.

Starting point is 00:04:38 Instead of my basic philosophy, I think I can summarise 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 to evolutionary origin doesn't necessarily mean that it's good.

Starting point is 00:05:00 It doesn't necessarily mean that 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. 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. Indeed, I think a lot of people do worry that that's the case and that people will assume that it's the case. 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. 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 will.

Starting point is 00:05:50 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, 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. Right to say that the differences are modest at best.

Starting point is 00:06:25 Yeah. 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 van diagrams, right? It's not just preference for violence and risk taking in 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. Yeah. Those are called multivariate sex differences. Yeah.

Starting point is 00:06:46 When you sort of cluster the differences together. I think that while that's statistically true, I think we need to be a little bit wary about the concept of multivariate statistics, 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.

Starting point is 00:07:12 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,

Starting point is 00:07:30 stack up the differences, and you'd find that they equally are massively discrepant from each other based on the multivariate statistical approach. So I think they need to be wary about exaggerating the magnitude of human sex differences based on that statistical approach. You could just as well exaggerate the sex differences

Starting point is 00:07:47 between New Zealanders and Australians or the British and the French or like I say too randomly. British and the French do that enough already. There's been a last few years, there's been a huge debate about what sex actually is. Yeah. What's the definition that you land on? 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,

Starting point is 00:08:16 you have two different gamete sizes and the small gametes are called sperm the larger gametes are called eggs is that across the board that is across the board no way so every almost every sexually reproducing male

Starting point is 00:08:31 yes produces sperm and sexually reproducing female produces eggs and I know this might 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 I mean it seems like so in biology it's not like math right

Starting point is 00:08:46 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, 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 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 an isogamous. Can you, what's an isogamous sexually reproducing species?

Starting point is 00:09:33 What are some examples of them? 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 would have been the starting position. So we all evolved from species that originally were isogamous. Their first of all, sexual reproduction would have evolved, and they would have been isogamous. They would have produced the same gametes and mixed them. But then that's evolutionarily unstable,

Starting point is 00:09:57 and that tends to fall apart into smaller and larger gametes. Why is it unstable? Because when you have same-sized gametes, the selection for any trait that will increase the chances of being one of the gamete, are producing gametes that are 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.

Starting point is 00:10:23 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. It's actually from a sexual survival or a gamete survival perspective, it's the grey 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.

Starting point is 00:10:54 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. They're also stripped, mortality, mobility by the smaller ones. 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. I can't remember what the stat is.

Starting point is 00:11:16 There's some stat around. Jerry, can you look at Chachip-T? How many sperm are produced per day, human sperm versus human eggs? It's such a hilariously big difference. Yeah. Okay, so broadly across the animal kingdom, in almost every single sexually reproducing species, there's a binary.

Starting point is 00:11:38 Yeah. There's a sex binary. 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. Yeah, what about the challenges to this? We have hamaphradites, within sex variation, intersex conditions. Does that disprove this? 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 feminine a team, just size dimorphism versus size monomorphism where they're about the same size.

Starting point is 00:12:17 But nonetheless, they are all either producing sperm or eggs. The vast majority within each group. 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 six feet seven. And she's actually taller than most men. Most men on average are taller than women.

Starting point is 00:12:43 Well, my friend's six foot two. You go, right, okay. But that doesn't necessarily disprove the way. The generalization. Exactly. The fact of the generalization is there. And even more so, the fact that the gamete size is definitional, as you say, oh, here we go.

Starting point is 00:12:58 I don't even know what that number is. Is that sperm, is that a billion sperm? 100 to 300 million sperm per day produced by healthy ed. Oh, no, no, no, no. I want this globally. total global sperm production, 200 quadrillion, eggs released, 70 million. Step it up, ladies. So I think fucking lagging behind.

Starting point is 00:13:18 We need to up the egg production, so I say. So much of the debate falls around nature versus nurture. Yeah. So much of it. How do you even begin to start to separate this out, right? No, almost no women have grown up in a society that hasn't had other women with the expectations of women. and almost a man have grown up in society that doesn't have the expectations of man.

Starting point is 00:13:41 How do we know that all of the sex differences aren't just socialization? 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

Starting point is 00:13:59 because we know that sex differences, their size, and the exact details of them, many of them, vary across cultures and very 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 sealed 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,

Starting point is 00:14:25 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. Let's 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.

Starting point is 00:14:54 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

Starting point is 00:15:14 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 what do you mean when you say innate? Unlearned

Starting point is 00:15:31 Right, unlearned, yeah. So there's an innate contribution and 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. Right, okay, which would suggest that there is a biological basis, or else, why would this big change occur when puberty happens? Exactly, and do so right across cultures. Would the suggestion from social roles, socialization theorists be that, while during puberty

Starting point is 00:16:02 the culture ramps up its pressure on people. There's greater expectation on young men and women to change their behavior. That would be the way that you'd have to, you'd have to try to explain it something like that, yeah. I think in the case of aggression. They're more, uh, yeah, more plastic at that age, perhaps. Yeah, yeah, yeah, you could do that as well. I mean, that's sort of implying an innate, uh, contribution to the plasticity, I guess, but yeah, not of the specific sex difference.

Starting point is 00:16:31 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 sets. differences appear despite culture rather than because of culture. Culture is trying to push down aggression right from early on. Parents, teachers early on, they actually tell off boys for

Starting point is 00:17:13 aggression, more than they tell off girls for aggression, not because they disapprove of girls' aggression, but just simply because boys are more aggressive. They have more cause to do it. I think fMRIs of developing fetuses in the womb can detect sex differences. is it three months? They can and I think even younger in some cases as well. What, are they, these boys and girls, these tiny, minus six-month-year-olds, are they learning that their brains are supposed to develop differently? Yeah, they've been socialised to develop different brain.

Starting point is 00:17:49 Inside of the world. Yeah, yeah. It's not plausible. Okay, so early development. Early development, appearing despite culture rather than because of culture. Yep. another one is that they persist often for a long time. So, for instance, sex differences and mate preferences were really consistent right

Starting point is 00:18:08 throughout the entirety of the 20th century in the US. Sex differences in career preferences as well, or career-related interests. They were evident from like 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,

Starting point is 00:18:37 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. Okay. I've learned from over a thousand podcast episodes that the easier you make your health routine, the more consistent you'll be. It's like golf, right? You want to keep it simple and not mix a bunch of pills. You want the eye of the tiger, not the DUI of the tiger.

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Starting point is 00:19:50 What are the sociocultural explanations that hold water? 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, there's something is making the difference. But it is actually quite tricky to figure out what, what it is that's making the difference.

Starting point is 00:20:17 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'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. They're equally likely to encourage them to be successful, equally likely to encourage them to be independent.

Starting point is 00:20:46 And another line of evidence against parents having a big role is what's called the second law are behavioral genetics. And that's the finding that when two people, okay, say 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 re-ed apart.

Starting point is 00:21:07 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 very 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 specifically.

Starting point is 00:21:38 What about the gender equality paradox? Well, that undermines another kind of sociocultural 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,

Starting point is 00:21:59 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 and 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. What would be some examples of how that would play out if that was true?

Starting point is 00:22:29 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.

Starting point is 00:22:48 It 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, which is... In the direction that you would predict as well. Yeah, so opposite to the direction you predict

Starting point is 00:23:08 if social role theory was correct. Yes, yes. But in the direction you would predict if you were taking an evolutionary perspective, I would imagine. Well, actually, you know, taking an evolutionary perspective, 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 prior the sex as a part even more. Right.

Starting point is 00:23:30 So I was actually very surprised. But it doesn't. That it doesn't. And that it does the reverse is the real surprise. What are the rebuttals that sociocultural explainers have for the gender equality paradox? There are a few. One is that people in more patriarchal societies, they tend. tend to, the men and women have little to do with each other. And so they have a more sort of

Starting point is 00:23:52 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. Right. Okay. Because they're just in, they're so siloed off in these patriarchal societies that they don't know what the fuck the other side's doing. Exactly. That's all that is. You're just in a bunker so much that you don't know what's going on.

Starting point is 00:24:26 It makes sense. It does. It does, but there's also plausible rebuttal to that rebuttal, which is that. Here we go. I fucking love it. It's so good. This is my shit. This is my shit.

Starting point is 00:24:38 So it doesn't just apply to self-report things like personality. You also find it for some cognitive abilities, I think spatial ability, for instance. you find it. You find that as well for physical traits, like height. Are you saying that in more gender-equal societies, boys get even better, better at throwing? I don't know if that is actually the case, but that would be an example. If there's research on that, I'm not sure if there is actually cross-cultural research on throw. Throwing is my favorite one, dude.

Starting point is 00:25:05 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. It's 90%. It's a huge, huge, huge difference. So my favorite study on this was, in order to negate the articulation argument,

Starting point is 00:25:51 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 hit. 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,

Starting point is 00:26:12 that spatial rotationist stuff is, the sex difference is pretty large and apparently maybe in a more gender equal society even more would be women would be hit by the tennis balls well that's possible yeah so the gender equality paradox it doesn't apply to every trade so it might not necessarily be

Starting point is 00:26:28 bad but yeah but you are right I think that was probably a 70 I think was a 70th study I'm not sure you could do that you couldn't do that you couldn't aim projectiles at participants in studies anymore sadly what's the largest sex difference between men and women Well, the largest ones are physical differences, physical sex differences.

Starting point is 00:26:48 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 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 there is big. And that's even

Starting point is 00:27:23 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 is, 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 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.

Starting point is 00:27:51 And you didn't, but it'll be no one does. I've read the book now. You've read the book now, so you've got a head start on that. Can you guess what it would be, Jared, the single biggest psychological sex difference between men and women? Is aggression? It's not aggression. I'll give you a clue.

Starting point is 00:28:09 and that's that it is related to reproduction pretty closely. What was that? Well, actually that is a big sex difference. Not as big as this one. Speak for yourself, too. It's the sex difference in which sex,

Starting point is 00:28:26 each sex is primarily attracted to. 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 this 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,

Starting point is 00:28:47 and they don't tend to mention that one. They often neglect to mention that very, very large one, but also that one that has quite a clear evolutionary rationale. Yeah, very interesting. Because if that wasn't the case, we wouldn't be here. Exactly. Literally. We literally wouldn't be here.

Starting point is 00:29:02 Okay, so what are the biggest sex differences? Let's get down to some brass fucking tax. What are the biggest sex differences when it comes to sex? When it comes to sex? Yes. One of the largest ones is the sex difference in interest in casual sex and sexual variety. So basically, sociosexuality, the trade of sociosexuality. No strings attached to sex.

Starting point is 00:29:24 Do I need to mention which direction it is? People might be aware of it. Yeah, someone can insure it, I guess. 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, you know, about Cohen's D equals 1.

Starting point is 00:29:50 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 sociose sexuality than plenty of men. I guess an intuitive way to put it, a way to make it intuitive, would be the same. If you imagine plucking two people at random, one man and one woman, with the fact size of 0.8, 0.1, probably 2 thirds to 70% of the time, the man will score higher than the woman on that trait.

Starting point is 00:30:29 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. Why? Why is that sex difference? That is getting right into

Starting point is 00:30:41 the central question of why there are any sex differences at all. I suppose we probably need to talk about the evolution of sex differences why they exist in the first place. Yeah. So we should jump to that. Can I just as an aside though,

Starting point is 00:30:55 we mentioned three of the six lines of evidence for inateness. Do we want to jump back and do the other three and then maybe get into them. Sure. So what do we do? We had the developmental sex differences. We had the resistance of cultural pressure.

Starting point is 00:31:13 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. And that's regardless of sex. 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.

Starting point is 00:31:59 prenatal testosterone, due to having a condition called congenital adrenal hyperplasia, or CAHH. They, as girls and then as women, they exhibit a lot of male typical traits. Less interested in playing with dolls. Exactly, yeah. Less interested in getting married and having kids, more interest in things-related professions as well. So that's pretty interesting. Do you make them more likely to be bisexual or lesbian?

Starting point is 00:32:28 Yeah, yeah, it does. It makes them more likely to be interested in other women sexually as well, either as bisexuals or as as lesbians. Yeah. Wow. So, so like a wide range of traits seem to be influenced by testosterone. So fourth one is correlates with hormones. Yep. The fifth one is cross-cultural universality.

Starting point is 00:32:46 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 than 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

Starting point is 00:33:16 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.

Starting point is 00:33:49 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 in what I like to call the maximum offspring number that male animals versus female animals

Starting point is 00:34:09 can produce. And in most species the males potentially can produce more offspring than females. Now, the 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

Starting point is 00:34:25 and the number of offspring produced can be greater in one sex than the other, and it's usually greater in males. Why does the average need to be the same if the variants can be different? Because it takes two to tango. And so every offspring that's produced is produced by one male and one female.

Starting point is 00:34:43 And most species are now. But if you can have one male servicing 20 females, why not have a 20 to one ratio? Well, that would be a 20 to one ratio in terms of the number of parents, but the average number of three sex would be the same. Because you've got the one male

Starting point is 00:34:57 or 20 times more than any female. And then 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

Starting point is 00:35:12 and the average is the same. I get that. Sure. Maybe I'm being stupid. Why is it not the case? Given that males are able to produce more children than women can.

Starting point is 00:35:25 than females can. Why is it not the case that there is a bias toward fewer males in the animal kingdom? Right, right. That's a great question. And that is one of the sort of early mysteries of evolutionary biology. And 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 each of resources and they're competing with each other and fighting with each other. It's not good for the species as a whole.

Starting point is 00:36:04 But selection of favour is 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 it's, I guess, useful to think about it from the parent's point of view. Like, is it better to have sons or daughters? and if there were 20 females for every one male,

Starting point is 00:36:26 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 was slowly favor an increase in the number of sons. Motherfucking, you can't beat evolution. Exactly. And the reverse, if there's 20 males for every female,

Starting point is 00:36:41 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 50-50. Yeah, obviously as well, there's survival and not just reproduction. We're not living in this perfect, hematically sealed, safe environment. Males do other things than just reproduce, regardless of whether they can do 20 to 1 or not.

Starting point is 00:37:06 Indeed. Yeah, indeed. Getting food, helping to protect, getting rid of other tribes, et cetera, et cetera. Yeah, yeah, exactly. And, you know, there are plenty of species where the male has, role in reproduction is just the reproductive act and then he then is off looking for other females. But we're not one of those species. I mean, that does happen occasionally.

Starting point is 00:37:29 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 variance. 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 have no offspring. 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.

Starting point is 00:38:02 Yep. One of the many that has none. Yep. And so that selects for traits like greater regression 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. engine, 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

Starting point is 00:38:32 to seek multiple mates and seek no strings attached sex, basically. So that's the answer to your earlier question, is that why you have selection for, like, strongest selection on males and females front interest in multiple partners and sex with that commitment. Right. Did you know your gut controls your energy, your recovery, how well you absorb everything that you eat, and the one nutrient that keeps it all running properly is fibre. Well, it turns out that 95% of Americans don't get enough of it, which is why I'm such a huge fan of Moments is Fiber Plus.

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Starting point is 00:39:37 below or heading to livemomomomentus.com slash modern wisdom and using the code modern wisdom. a checkout. How does parental investment influence the evolution of sex differences? 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 mayor ought to produce an offspring just in principle only needs to engage in one sex act. So he can mate with multiple females

Starting point is 00:40:29 and have tons of offspring because he invest potentially little in any given offspring. Whereas the females, on the other hand, they invests a lot in each offspring. That lowers the ceiling for the number of offspring they can produce. Therefore, you have to be choosier. 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...

Starting point is 00:40:55 Is that the key driver? Well, I think the key driver is the difference in the maximum offspring number or the reproductive variance. Right. Because it's not just shaped by parental investment. Behaviorally, that shows up as parental investment. Well, that's a big part. of it, yeah. So the parental investment is the major cause of the sex difference in maximum

Starting point is 00:41:14 offspring number, but other things do come into it in different species. But gestation period, too, is like a biological imposition on parental investment. Indeed. Actually, is how long it takes to just make a baby considered part of parental investment? That is part of parental investment. Right. And parental care is and nursing is. Obviously those two, but I wasn't sure whether or not it's classed parental investment.

Starting point is 00:41:38 is classed is actually the making of the baby. It is because it forecloses the option to make other babies. Understood. Yeah. Yep, yep, yep. But ecological things come into it as well. So one example of a factor other than parental investment that influences the reproductive variance, as ecological factors.

Starting point is 00:41:53 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 numbers about the same because it's 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

Starting point is 00:42:18 what's Bateman's principle Bateman's principle so that is the idea that reproductive variance is greater in males than females in most species and then Trivers'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, the males invest per sperm.

Starting point is 00:42:48 Trevor's said Robert Trivers, who died recently, he said, it's not just that. Actually, it's 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. what matters. And I would just add that parental investment is the big one, but other things as well determine reproductive variants. What is the,

Starting point is 00:43:12 it's about 40% of males that with human males ancestrally reproduced and about 80% of females. Is that right? I have heard that number, bandied about. I actually think that probably

Starting point is 00:43:23 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 so just 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... So the 4080 number you think is wrong?

Starting point is 00:43:43 Yeah. Right. I think so. What's the reason? 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.

Starting point is 00:44:00 And so we have high levels of bi parental 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. 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?

Starting point is 00:44:24 That is what I'm saying. Bingo, I fucking know what evolutionary psychology do. Don't test me on this. I fucking understand this. It's the only topic I understand. So you get very into reproductive success. What do you, what do you reckon it was then? If it's not 40-80, feel free to just bro signs that there's a cap you can point.

Starting point is 00:44:45 I probably shouldn't put a number. Other than to say, I think it's smaller. I think it's small. I know, I know. That's why I'm in the room, dude. I'm going to put this thing on for the rest of the conversation. I think you've got these as well. That's if you want to say something insane.

Starting point is 00:45:01 Okay, cool. Well, I'll keep it here. Yeah, in case you want to say something absolutely insane, you're allowed to put that on. It's actually saved me once already. I got, 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 in the glasses. Well, indeed, yeah. Nothing's changed.

Starting point is 00:45:17 Nothing's changed. Yeah, okay, so we've got a, it's like an interesting, I guess an interesting pivot. on what people think. That sort of 4080 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. To me, like infant mortality.

Starting point is 00:45:49 Right, right, right. 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 reproduces. it's how many survived. Yeah, survived to reproduce.

Starting point is 00:46:05 Yeah, the grandparent optimizing machine from your previous book, which is fantastic, and everyone needs to go on like that. The April understood the universe. 80% of women having grandchildren producing, 80% of women being grandchildren producing people seems insanely high to me. I guess the thing is that they would have had a bunch

Starting point is 00:46:31 of kids. And only about 50% would make it. About 50% would make it. And so if they, you know, have sex, for instance. That's what it is around about 50% that are born and go on to reproduce. 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 had lowered that number to very close to zero because that was, I think, a massive cause of misery throughout most of human history. Was it Darwin lost a bunch of kids? He did, yeah. He had 10 and 3 didn't make it to adulthood.

Starting point is 00:47:08 I think that's the love is. Is it your book or was it, I think this might have been the moral animal. Yeah. 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. Yeah. And the reason for that, the evolutionary reason that Robert gives for it, is 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 two years old, that's horrible.

Starting point is 00:47:56 but 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 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? No, that is the story. Yeah. And there's pretty good evidence on it as well that grief tracks reproductive value of the individual. No fucking way.

Starting point is 00:48:32 So this has been reproduced. Because that book's 30 years old now. Yeah. Yeah. Yeah, the average grief levels go up and up and up. As reproductive value goes up 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. starts coming down again as people get older.

Starting point is 00:48:57 So fucking fascinating. How is everyone not obsessed with evolutionary psychology? I completely agree. It's so cool. It's fascinating, right? It's so fun. And sheds light on some of the most fundamental stuff and life. Yeah.

Starting point is 00:49:07 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. He said, oh, so you're just saying that, All that children are that's produced for you to be happy to do anything. It's like, you don't need to lord our ultimate evolutionary drives in order to understand and respect them

Starting point is 00:49:41 and accept the fact that they are important influences on our behavior. 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 think about it, though, 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.

Starting point is 00:50:07 This is sad because this kid was close to having kids and then I would have been. Well, 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 Evolution. theory, but one of them is a lack of understanding about the difference between proximate and ultimate motivations for behavior. Yeah, exactly. So one of the big ones. Yeah, like the misunderstandings.

Starting point is 00:50:36 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. 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. I don't want to have kids. I love to have sex. Yeah, yeah, exactly. So it doesn't make sense. But they've just misunderstood the item.

Starting point is 00:51:21 Yeah. Because it's not a psychological theory. like the genes-eye 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. Not the ultimate. Exactly. Yeah, yeah. And, you know, with the, what's it referred to as that theory of the sexual, not sexual value?

Starting point is 00:51:46 Of Darwin's daughter dying, what's the? Oh, yeah, reproductive value. Reproductive value. No one 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. Exactly. Horrible, horrible thing to say. But it doesn't need to, it doesn't need to be something that's in your mind to go, how could you claim that this mother is feeling that, thinking that at the time and that's contributing to a grief? No.

Starting point is 00:52:22 She's not. She just loves the kid. Yeah. 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?

Starting point is 00:52:40 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. Exactly. And even though it does seem bleak sometimes, I don't see that other explanations, sociocultural explanations, would be any less bleak, you know. Oh, so you're telling me that I'm at the mercy of the memes and trends of the modern world. Well, exactly. And some guy decides to start 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.

Starting point is 00:53:15 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? 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.

Starting point is 00:53:58 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 hard enough. Yeah. Horrid. And I guess so 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. And sometimes it is positive. So natural selection has given us a whole range of less than noble traits,

Starting point is 00:54:25 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 things. Care for others, to care for others. Yeah, exactly to be old-tested. I guess one, 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.

Starting point is 00:54:44 Is it, are humans unique in this regard? 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, volume of children across a lifespan, Bateman's principle, variance in reproductive success. But humans do seem to be somewhat of an outlier in mammals and especially in the animal kingdom. Yep. Yep. What wrinkle does that throw in? Well, yeah. So we, we So the question, are we unique? So the way in which we are unique, we're very unique among mammals,

Starting point is 00:55:25 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 bipedal care.

Starting point is 00:56:03 And so this is a funny thing. 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. No way. Yeah. That's because of our pair bonding and our bip parental tendencies. Which is a reinforcement that the parental investment is the key driver of sex differences. Yep, exactly.

Starting point is 00:56:29 And are the differences in the hilarious. Most birds, hang in a second. Yeah. Yeah. Most birds are kind of like dinosaurs and humans are closer to birds than they are to most mammals. Yeah. Which means that humans are kind of dinosaurs. Yeah.

Starting point is 00:56:44 That's by evolutionary logic. That's great. That's great. Do you want this? Yes. No, no, I don't need that. I don't need that. 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. That's fucking gold.

Starting point is 00:57:00 It's wild, right? That's fucking go. 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 in reproductive variants, that is true across the animal kingdom. And the rules about that apply to us as well. And the fact that we do have a sex difference in reproductive variants, men do have and have always had greater reproductive variants than women.

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Starting point is 00:58:26 with your health and start knowing. And right now, you can get $25 off, bringing it down to $340. So get the exact same blood panels that I do and save $25 by going to the link in the description below or heading to functionhealth.com. slash modern wisdom using the code. Modern Wisdom, a checkout. Isn't there an interesting inversion of this in spiders where female spiders are bigger than the males? 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.

Starting point is 00:59:01 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 don't need to be much bigger. They don't need that much room for sperm. Yeah, exactly. Yeah.

Starting point is 00:59:22 So the gamete size difference, sperm are bigger than eggs, is reflected in the physiology of the species. Oh, that's so fucking cool. 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 for producing more eggs

Starting point is 00:59:45 so they've got certain size sort of push for them to be bigger but you've got an even stronger push on the males to be bigger as a result of intersexual 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

Starting point is 01:00:06 they get even bigger than the females. All right, meat and potatoes. Getting back to sex differences in sex drive. Yeah. What casual sex, sexual variety, cheating, what's going on there? 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

Starting point is 01:00:26 missile going out to seek multiple partners and is therefore more likely to have more offspring. If he's successful than that, then 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 variants among males and our species is somewhat constrained, still greater than among females.

Starting point is 01:00:58 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. 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.

Starting point is 01:01:20 The parenting differences is the main source of this, so that, you know, is like the discrepancy in male investment in kids versus female investment has been massively reduced. And that's the driver. And that's the bi-parental investment is the nerfing. The reason for the nerfing of all of the others. Okay, again, I'm only going to make this fucking disclaimer once, but we said it, we said it previously, but I think it's worth saying again,

Starting point is 01:01:46 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. 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 it explained it in

Starting point is 01:02:10 sociocultural terms, 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. Yeah, exactly. And all our behavior must have causes, right? So if we're going to say that if we can identify the cause of 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 cause. Whether it's evolutionary or cultural. Or most likely a combination of both.

Starting point is 01:02:46 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. That's so 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. Yeah, that's why I would right. That's a massive difference. 20 million to a thousand, 500. It's probably similar to that ratio we had up there before. It's almost exactly the same, yeah. What about men being more turned on by

Starting point is 01:03:22 visual triggers? Yeah, that's another big sex difference. Both sexes are to some degree. You know, both sexes are interested in good looks and a mate, but it's stronger men than 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, two-thirds 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

Starting point is 01:04:09 men are much more avid consumers of porn than women are. What is the reason that women are much more avid consumers of romantasy and romance novels than men? 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, now it is interesting. We've been a very important. We've been. 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.

Starting point is 01:04:46 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, in falling in love and forming committed bond with a partner. 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. Exactly right.

Starting point is 01:05:13 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 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

Starting point is 01:05:45 of more romantic than women. They are more lucky to suffer after a breakup. Fall in love more quickly. Say I love you more soon. Exactly. Exactly. So why aren't they more into romance novels? I don't know.

Starting point is 01:05:55 Maybe they're just too busy with the porn. Yeah, true. Dude, I mean, I sign next to a lady, lovely lady floral dress. slightly old lady on a flight a few months ago. And she had an iPad up resting it. And it was a big, big fuck-off font. And she was reading some romantic-y thing. And she was getting to the good stuff.

Starting point is 01:06:16 And I mean, I couldn't. 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. me and they've got an iPad, I think, oh, that's great because it's going to, or whatever, the Kindle or something, it's going to influence me to not be a degenerate. All I wanted to do was put a pair of blinkers on. I'd like to focus on some brain slop stuff.

Starting point is 01:06:46 I've never, I've been meaning for ages as a sort of anthropological study to read one. Excuse it however you want, dude. Excuse it however you want. 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. A girl tames boy And then they live happily ever after him And they do involve sex, right? Well, yeah, I mean, there is some sex in them

Starting point is 01:07:09 At least there was in hers And the one that she was reading it. Yeah, exactly. I mean, there's some interesting stuff, right? The number of, if you have a sexual fantasy, mental sexual fantasy, men will cycle through, I think it's between four and six

Starting point is 01:07:22 different partners on average during... Is that four and sex or 46? 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 going to guess that this would be reflected in romance novels uh in fact i know that this is the case because i've been on the cover of a bunch of them and during those novels at least i would say on average most yeah the women who are the

Starting point is 01:07:50 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 yeah it tends to be a a a between two different life directions. It's not a kind of ruthless conveyabout 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 a bad man, Bussey's book,

Starting point is 01:08:22 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. Putting a coin into a vending machine. Putting a coin into a vending machine. You're fucking kidding me. Although that was a joke.

Starting point is 01:08:38 I'm not sure. There's actually research on that. That obviously wouldn't surprise me. No, no, likewise. There is something penetrative about gambling and it was on top of the risk-taking on top. That's it. Overperception bias as well. Another great example that I learned from Badman by David.

Starting point is 01:08:55 Yeah. Yeah. And that's research by him and spearheaded by his form. student Marty Hazleton, yeah, the sexual overperception 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 inferred, than women are in the case of men. So the more likely you think, yeah, she's into me when actually they're just in a little dream world, and that's not actually true. Men are more likely to think that women are interested in them than they are, and women are more

Starting point is 01:09:28 likely to think that men aren't interested in them when they are. Yeah. 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. Right. Yes, right. Yeah. Exactly.

Starting point is 01:09:46 So it seems to be maybe some kind of projecting yourself into the world kind of bias. Yeah. So it's a failure of cross-sex mind reading. Yep. But it's also specifically in an over-perception bias 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,

Starting point is 01:10:11 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. Exactly. And this, again, fuck, I'm just going to 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 & Gamble, who is the one that

Starting point is 01:10:49 that Indian dude made the whole fucking conspiracy theory about? It went insanely viral. I bet your fishhead Asian wife doesn't have these cannons. Do you remember that? Goldman. Goldman Sachs. Goldman Sachs. Yasmin's mum works at Goldman. We should get the inside scoop. Yeah, my guest book is mom is like real, real high up at Goldman Sachs. And then there was that huge. Did you see this thing kick off a couple of months ago? I don't think I did that.

Starting point is 01:11:16 No. It just, it was a guy me-toeing a very, very high up. Right. Okay. Exact. Yeah, a bit of a role reversal. at Goldman. But as soon as the proposed accusations came out, there was no... It was so rare.

Starting point is 01:11:32 It was at the most... It would have been incredibly extreme for a guy to do. Yeah, yeah, yeah. And the fact that everybody intuited, like, really? Yeah. Sex differences. Yeah, yeah. All right, how do gay men and lesbians reveal what each sex wants?

Starting point is 01:11:49 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. Unsullied by the other sex. Exactly. Yeah. So men are compromising by having less because basically women are thwarting their plans. Yep. There's no gatekeeper.

Starting point is 01:12:24 Exactly. And yeah, whereas straight women had compromised it with men and maybe having more than more casual sex than they would choose, at least as revealed by lesbian behavior. 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. Yeah. But that the compromises is the guy going, okay, fine. She's setting, she's setting the level more than he is. Yeah. I do think that there's kind of a, and this is, I mean, look, are we really going to say boo-hoo, poor men not getting exactly what they want? But I do think that it's a kind of compromise that might be invisible to women because sexual entitlement comes wrapped in some really ugly,

Starting point is 01:13:20 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

Starting point is 01:13:35 that they are paying that 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 yeah indeed

Starting point is 01:13:48 and I guess I guess it's more I guess that men are doing that more often like some women are doing the same thing no doubt but it's just fewer women than men

Starting point is 01:13:59 in that situation yeah there's also more dead bedroom in lesbian relationships I've heard that yeah there's some phrase like that isn't there the lesbian dead bed or something

Starting point is 01:14:12 yeah yeah okay so make preferences when it comes to make preferences is it surprised how similar men and women are when it comes to what they look for in a partner? Well, I guess it fits with the generalization

Starting point is 01:14:27 that in a lot of ways we are quite similar, that 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.

Starting point is 01:14:45 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

Starting point is 01:15:17 that's a bigger deal for men than for women. Men put more weight on looks and a mate than a long-term mate than women do for the reasons that I mentioned that I mentioned earlier. Women on the other hand tend to put more weight on resources and status in a long-term mate

Starting point is 01:15:35 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. Trace like kindness. And likewise with women, resources and status animate, they're important, but other things, again, like kindness, tend to top the list of the things that are most important for women. 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.

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Starting point is 01:16:48 Are heading to drinklmnt.com slash modern wisdom. That's drinklmnt.com slash modern wisdom. What's the evolutionary logic of non-physical mate preferences like wealth and status? 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 biparental species. So a guy who is able to access resources, you know, 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,

Starting point is 01:17:22 to co-rear the children. And that's explanation, I think, is most popular and most likely. There is also an explanation, though, that it's primarily a human equivalent to 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 good genes and he's going to pass on whatever traits enabled him to do that to his male offspring. They're going to be able to do the same. They're going to 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 is both a fitness indicator, but also is actually

Starting point is 01:17:59 useful in the context of bi-parental care. You mentioned this is to do with long-term relationships. Yeah. 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? 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.

Starting point is 01:18:27 And when it comes to low-commitment relationships, then that difference basically evaporates. And women at least is interested in physical attractiveness in a mate as manner, if not, you know, some research suggesting maybe even more interested in physical attractiveness. Why would that be the case using evolutionary logic? Because, 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 genes that the male is going to be passing on, and therefore

Starting point is 01:19:05 traits that are indicative of good genes are much more important. They take center 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. And what you want, if you have a short window to do this assessment, and you want the most obvious representation of those good genes as you can.

Starting point is 01:19:36 Exactly. and physical looks are bad. I'm sorry, your ability to do non-kin altruism and reciprocal care and kindness and your ambition over time. It's like, you know, great, but I don't have time to assess that in the same way. Yeah, yeah. 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,

Starting point is 01:20:01 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, or buying a VIP booth, status, into an immediately transactable and obvious advertisement

Starting point is 01:20:30 in case there is some of this short-term mating that's going. And 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. Totally. And it's interesting, right, because these are human equivalents of the peacock's tail.

Starting point is 01:20:50 And whereas, and 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 peacocks 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.

Starting point is 01:21:09 Why isn't it that women aren't turning up in a fast car with an expensive watch outside? 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 and 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.

Starting point is 01:21:53 Yeah. 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. Yeah. 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.

Starting point is 01:22:20 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.

Starting point is 01:22:46 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. Yeah. Kind of fascinating. It's really fascinating, right? And just the same mate preferences emerge in that context as emerge in actual interactions,

Starting point is 01:23:10 social interactions. There's that Clark Hatfield study as well, right? The on-street interview? 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 I find you very attractive. And I was just wondering whether you wanted to dot, dot, dot, dot. And then they would finish that

Starting point is 01:23:39 sentence was 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 that go out with me, question, in the first study they did, there was basically no sex difference. So it was 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.

Starting point is 01:24:13 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 in the first study, about 67% of men said yes. so actually higher than the date rate. More likely to go up to your room than I am to go on a date with. Exactly. Filarious.

Starting point is 01:24:35 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 at even higher rate of men. Whereas exactly 0% of women said yes to the, the kind offer. And not only that, but actually the manner of the refusal differed between men and women. So the 25% of men who said, thanks, but no thanks, well, they kind of said that. They were

Starting point is 01:25:09 polite about it. And some of them said, I'm really sorry, I'm meeting my fiancé or whatever. A bunch of them even asked for a rain check, apparently. They said, I can't, I'm not very busy, I'm meeting my fiance or whatever, but maybe we could postpone the sex till later. Whereas, none of the women who were refusing were polite about it at all. They were reacted more like, are you crazy? How dare you ask me that? None of them apologize and asked for a rain check. Why do you think that the manner of refusal was so different?

Starting point is 01:25:41 I think that it reveals two reasons. So one is there's this average difference in interest in casual sex, and 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

Starting point is 01:26:02 and to have to, you know, 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

Starting point is 01:26:22 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. Feels like a danger.

Starting point is 01:26:44 Exactly. Some of that emotional activation of, hang on, I'm going to go with this person who I don't know, who is physically stronger than me. Yeah. Explosion. Exactly. As opposed to, there's just way less of a, it feels less of a physical threat to make.

Starting point is 01:26:58 Exactly. Those both make, those both make complete sense. There's an interesting wrinkle in this. Now, I'm going to guess that when they did this, the Clark Hatfield study, they must 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.

Starting point is 01:27:20 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 two 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 doing it. Right, right, right. Because they go, hang on, you think that you've got a chance with me? Yeah. Oh, my God. It's basically an insult. Yeah.

Starting point is 01:27:51 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. Yeah. And a guy that you think is a three comes up to you. That is, it tests your own self-perception.

Starting point is 01:28:10 And you go, fuck, maybe this is how the world sees me. Yeah. Do you not think I'm an eight as well? Yeah. Yeah. Yeah. Yeah. And I think that that it feels like an insult.

Starting point is 01:28:19 And the same thing like, fucking no, get away. Because rightly so, you're kind of pissed that this thing happened. 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 in eight and approached by three. Well, preference for casual sex. Rarer approach in any case. Indeed.

Starting point is 01:28:43 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. That's the power of my attractiveness. I think that's, I think that's how a lot of guys would take it. And I agree. That's why it is, it is flattering. It's like somebody running for a bus fast that they really, really want. You know, like, well, they must really want this bus, because look at how fast they're going. Yeah, yeah. And guys tend to be more overconfident than women. Yeah.

Starting point is 01:29:21 What about sex differences in aggression? 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 it's, 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.

Starting point is 01:29:47 and maybe, you know, pluck two people at random, guy and a gal, two-thirds of the time, the guy's going to be high and 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. So when you go to low levels of physical aggression, slapping, pushing, that kind of thing, that you have a larger sex difference, men doing it more.

Starting point is 01:30:11 Then you get into serious physical aggression, violent crime. That's much more men than women. Independent of who the victim is. 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 predominate. 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, and almost all data sets that I've seen.

Starting point is 01:30:41 But, but yeah, the 90% plus perpetrators, very, very strong effect. 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 under 70 to 80% of homicide victims. In chimpanzees, male commit 92% of chimpsides and are 73% of victims, virtually identical numbers to humans. It's 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, but they are more. But the size of the sex difference in lethal aggression is the same. And the size of the targets, the sex difference and the targets of aggression is about the same as well. Why? That is a direct offshoot of the fact that it's the selection for getting to be one of the few males that has many offspring rather than the many that.

Starting point is 01:31:41 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. And 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,

Starting point is 01:32:15 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 of the fact that the sealing 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 won't boost the number of offspring they have. have because the ceiling is lower. So it's costlier for them. The costs aren't worth the risks. Yeah. Plus more fragile, more easily killed, like just generally. Yeah. But that's possibly just an

Starting point is 01:32:53 offshoot of the fact that there's been less selection on them for aggression. Right. So there's been more of that on males. So you don't need to build up the defenses in order to be able to, that's why we have a brow ridge. That's why we've got bigger hands. Exactly. Yeah. To 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 that a guy who is violent is able to be violent. 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 board. I think, is Andrew done Kravmagar?

Starting point is 01:33:46 He's into martial artsy type stuff, I swear. I think so, yeah. And he was explaining how many, at Kravmagar, this Israeli martial art, very lethal supposedly martial art. A lot of the guys that he trained with unbelievably lethal, physically. Yeah. And a lot of the training was them learning to turn it off, not turn it on.

Starting point is 01:34:10 Interesting. And that 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. Yeah. 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.

Starting point is 01:34:48 Indeed. It's interesting, isn't it? Having that kind of temperament, violent temperament, and the capacity for physical aggression is really a mixed blessing for women. It's great if the guy's going to protect them, protect the family. But it's not so. so great because he can potentially turn that against them as well. So, you know, you get the evaluation of those traits. It can increase attractive. Like aggression itself, I don't think, increases attractiveness. Protactiveness does.

Starting point is 01:35:18 Muscularity and the light can increase attraction somewhat, but because it's a mixed blessing, I think women are also interested in the guy's character. Muscularity seems pretty reliable at improving attractiveness. Yeah, yeah. It's probably the most easily modifiable thing that guys can do. Right. Yeah, yeah. I think, in fact, I think William said,

Starting point is 01:35:34 that this is exactly the case because he's looking at his in-cell stuff. Yeah. Did you see, now I, bro signs this. I put the, I put the captain of bro-signs hat on when Mackin came through last time. Yeah. And I said, I'm pretty sure that I've seen a study that says a woman would be, would lose more attraction if her partner didn't protect her during a physical altercation than if he cheated on her.

Starting point is 01:36:02 Right. And then the guys went and replicated it and... And you were right. I was right. Excellent. I mean, it wasn't my original insight because I found it in a study that I couldn't discover again. But the same insight being true, the protectiveness, the ability to protect. In fact, do you know it is?

Starting point is 01:36:18 It was the willingness to protect. Yes. Wasn't even the ability to protect. Yes. 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 misses and this potential assailant, It doesn't mean anything.

Starting point is 01:36:32 You might as well not be. Exactly. You know, yeah, exactly. I wonder, do you know what it is? I wonder if this would be, this is another new skew that the guys should do. Yeah. 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? That's an interesting one.

Starting point is 01:36:51 You know what I mean? I don't know. I do know. But in terms of the character trait, it would 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 If they're not going to do it anyway To be able to in future

Starting point is 01:37:08 There is that, yeah But if I'm not going 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 Yeah Yeah, but if he's definitely not going to do that That's going to be very off-putting

Starting point is 01:37:25 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. It's trade-offs, though, right? Why is it that women care more about a man's height than women do? Is it plain to this? I think it probably is. I think it must be.

Starting point is 01:37:40 I think it's within a cluster of traits that determine protectiveness and the like. Muscularity, height, they're all part of the same package. And it's interesting, right? They does seem to be rarely, really high on the list for women. So you see, very important. 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.

Starting point is 01:38:19 Wouldn't it be funny if we gave you a height filter? That's now an actual feature. It's an actual feature, right? 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 5-7, 5-6, 5-5, very few words. And I had this insight, the tall girl problem. And it was born out of a friend whose sister is 5 foot 2.

Starting point is 01:38:44 Sorry, her sister's 5 foot 11. So if she wants to wear heels on her wedding day, she's like professional athletes. Yep. 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,

Starting point is 01:39:01 I might go up and talk to him. And they round the corner and they say, see him with this five foot two Latina bombshell. And she kicks off at her sister quietly and says, like this fucking bitch. Like she could date five foot five, five foot six, five foot seven. Why don't you have to take a guy that's a foot and a half taller than her?

Starting point is 01:39:22 But the point here is, if we're talking about protectiveness as the driver, the fact that your chick is a 5-2 Latina, not a 5-11 American 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. Yeah, yeah, yeah, indeed. You know? And this is why I think you don't see much of a height compensated. effect. Yeah. Other than, I guess if you're five foot two, you can't really tell the, like above probably

Starting point is 01:39:59 5, 10, it's all just up there. Yeah. It's just like it's over there, you know. In the clouds, exactly. Yeah, 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 I'll guess how tall my wife is, she's five foot four.

Starting point is 01:40:21 So. these bloody bitches how dare they take the toll man uh all right sex differences in stalking what about that uh women do a lot more of it joke men do a lot more of it men do a lot more of it it's i think it's just um an example of the fact that men are more you know proactive seeking out mates seeking out multiple mates uh and stalking is the subcategory of that when it gets into extremely inappropriate examples of that. And also, I guess, yeah, it's also, it's not just mate-seeking, it's also where people get fixated on somebody.

Starting point is 01:40:59 And both sexes can do that, they can get fixated on somebody. Sort of limerence type thing. Yeah, yeah, exactly, limerence, yeah. So sort of falling in love, except that we call it limerance 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

Starting point is 01:41:23 limerence and being fixated on somebody. What about 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 both 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. Um, but given the fact that you have high male parental uncertainty. Yeah. Because you've got concealed ovulation and you don't have the same kind of sort of harem, hematically sealed sphere when it comes to men and women, human and women. Um, stalking, I could see a surveillance behavior. could be a part of mate guarding

Starting point is 01:42:21 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

Starting point is 01:42:49 uncertainty. 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 to be jealous and prone to jealousy. And one way that that manifests, so jealousy drives mate-guarding behavior. And one subset of mate-guarded 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 neighbor or the good-looking guy or woman at work?

Starting point is 01:43:27 And then if you take that to an extreme, that's where it becomes surveilling behavior. 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 in. So when we're talking about surveillance, jealousy, mate guarding, etc. I mean, William put these stats up recently about what the percentages of men who would sleep with a female friend.

Starting point is 01:44:00 It's huge. It's like 50% of relationships used to be friendships. Yeah, yeah, yeah. So that's like 50%. Yeah. It's a huge amount. And I think, when you put all of this together,

Starting point is 01:44:18 you end up with the 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.

Starting point is 01:44:35 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 wife in these sort of, more subtle, hard to detect motivations and behaviours. 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

Starting point is 01:45:03 are particularly interested in sleeping with male friends that they have. But because of the sexual over-perception bias, the male friends in question would probably assume otherwise. What's the sex difference around sexual violence? Sexual violence are men are much more likely to do it. And that is partly just an offshoot of the fact that men are more aggressive. Yeah. And the numbers are pretty big. So sexual violence is much more often perpetrated by men than by women.

Starting point is 01:45:35 It's not, it doesn't only go in the one direction, though. But it is just much more common for men to do it. Do you get any idea what the numbers are? 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.

Starting point is 01:45:52 Directionally correct, specifically vague. Indeed. So directionally correct, and I'll, you know, I've got to say that it is a big difference. Yeah. 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 forms of sexual violence and sexual assault and harassment and the like.

Starting point is 01:46:16 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 or excusing it is natural. Exactly. But again, natural doesn't mean good. Yeah.

Starting point is 01:46:29 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. Yeah. Yeah. analysis is not justification. Yeah, yeah, exactly. You know, that's a fucking Hassan Abbey quote. That's like a Hassan Piker quote.

Starting point is 01:46:46 He got counsel for talking about some stuff to do with the right wing. Yeah. That is an absolute slammer of a line. Analysis is not justification. Yeah. 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

Starting point is 01:47:09 to ask for consent as well. 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 interests 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.

Starting point is 01:47:46 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 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.

Starting point is 01:48:06 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 females' nature to be upset by it because it compromises female choice. Oh, that's interesting. Yeah. That's interesting Not only is it

Starting point is 01:48:39 fucking heinous But you know That because Somebody Because this male committed that behaviour They've had to disregard

Starting point is 01:48:52 The entire female Wide value That is supposed to be universally protected Well right Well I mean She's evolved

Starting point is 01:49:03 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

Starting point is 01:49:20 and has just taken that away from her, taking that choice away from her has gone against she's evolved to be more to be choosier and I think this I think that the inability of men to fully understand what fear of sexual violence must feel like.

Starting point is 01:49:42 Yeah. 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. Yeah, yeah. Is treated with a very strong antibody response from women. Indeed, yeah. And guys do, you know, guys, the idea of going to prison and being raped in prison, obviously, is terrifying to a lot of guys. So they do get it to some degree. But, and I guess particularly when it comes to the sort of lower level stuff, like 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 well. 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 would have happened in reverse if it would have happened to him he might not like it but he on average is not going to be quite so upset by him it's interesting that

Starting point is 01:50:49 people who denied 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 indeed yeah indeed there's a directionality to the way that this analysis happens. Yeah. Why is it not that we've got 50-50 in terms of homicides? Like that we should do. Yeah, yeah. Women should be free to commit just as many killings as they want to.

Starting point is 01:51:14 Yeah, and that has been kept down the fact that they're not doing it. Yeah, the patriarchy, the damn patriarchy. 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,

Starting point is 01:51:39 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 violence is bad.

Starting point is 01:51:53 And we know that because another way to get rid of that sex difference in violence would be to increase the female level. 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. So point is, yeah, equality is not a good thing in itself. Yeah, yeah, yeah, yeah. Okay, what about the differences in parenting? 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,

Starting point is 01:52:22 people aren't so keen on. And that refers to the fact that in every culture, again, 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. They 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, so like the guys are using it as an excuse. It's just natural that you should want to be changing the nappies and doing these things like coincidentally, I would rather not have to do.

Starting point is 01:53:17 So that I think is the concern. But in a way, it's ironic. So the fact that people consider 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 are more. This has 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. Yeah, yeah, yeah, yeah.

Starting point is 01:53:49 I think you mentioned that when we met the first time, right? Yeah, yeah, yeah, the soft bigger tree of male expectations. Soft pay tree. 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...

Starting point is 01:54:10 It's really a real view. It is, really, isn't it? It is. It is. And so if we're taking 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,

Starting point is 01:54:29 then we're taking a negative valuation of a more female typical trait, and that is really sexist. Yeah, yeah. What's the Kibbutz experiment? The Kibbutz experiment, so there were these Kibbutzim that they had in Israel, so these were these communes,

Starting point is 01:54:47 like highly egalitarian communes where they wanted to get rid of all traditional kind of structures, including traditional 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

Starting point is 01:55:12 and then they had dedicated adults within the group who would be the primary, primarily in charge of looking after all the kids. So the kids weren't living under the roof of their biological parents. They didn't think, you know, 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 want to get rid of that.

Starting point is 01:55:38 They tried it. They did manage to make it work for a while, but what happened was that, just 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,

Starting point is 01:55:58 most of the, 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 by men.

Starting point is 01:56:14 They may 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.

Starting point is 01:56:40 Culture is pushing the opposite direction. Exactly. Yeah. 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 screenup 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.

Starting point is 01:57:07 And it was just one of those ones with the 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. It's tough, right? There's a real, that's the work, family, you know, clashing roles that both sexes to experience, but it does seem to be still a bigger deal to women than men. 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 agree, I think, I mean, the UK gives nine months, which is still not enough, but

Starting point is 01:57:44 feels at least remotely humane. Yeah. And the US is basically, once you're out of the hospital, you're back to work. 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 mum. but by being not just a mum, I'm also missing out on a lot of the joys of motherhood. It's a kind of hard to win that situation. Women really don't have a good outcome there.

Starting point is 01:58:30 Yeah, and people in general, I mean, in a way, you know, there are these kind of trade-offs for everybody always, 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 course. What about differences between men and women in sexual jealousy? That's an interesting one.

Starting point is 01:59:04 So both are prone to it, like I mentioned. But for the reasons that you mentioned already, 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, you love going off and sleeping with somebody else, or just forming a close emotional bond with somebody else. Both of those are upsetting to most men, but men are more likely to say that the sex is more upsetting than just the bond.

Starting point is 01:59:36 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, the 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 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

Starting point is 02:00:11 woman's kid. Whereas, you know, 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 is the good-looking next-door neighbor'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'll be very, very upset about it.

Starting point is 02:00:45 Very often it destroys the relationship. But it's even worse. For most women, if the partner gets emotionally involved with somebody else, because then whether they want the relationship to end or not, it's going to end because they're very likely going to leave and set up shop with the other woman. I have an example that I heard about from a while ago, that a friend was on 23Mee or Ancestry.com and one day in the 30s got an email notification saying you've got a new half-sister.

Starting point is 02:01:20 Right. And just 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. Right. 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 what happens to sexual jealousy and intimacy jealousy

Starting point is 02:01:55 and the fear of resource provisioning needing to be split. When you've gone past all of those things, because you have this. you know, three decades, 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 like separate out all of the typical areas. Now trust, infidelity, all of those things, obviously horrible, but kind of fascinating too.

Starting point is 02:02:36 It is really fascinating. And I wonder if this could be an example where proximate and ultimate like 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.

Starting point is 02:02:51 I'm 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 nowhere to help me with it. That's the evolutionary rationale. But it could just be a gut reaction.

Starting point is 02:03:04 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 anyway. You know, like he's a trust issues and those kind of things are going to kick him.

Starting point is 02:03:16 Could kick him just as strong, even though evolutionarily the circumstances, it doesn't matter anymore. The gut reaction that evolved might be, might not discriminate those details. What do we know about sex differences in people? personality? 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,

Starting point is 02:03:41 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 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.

Starting point is 02:04:26 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 conscientiousness, but not always. Some studies don't find that. extroversion on average women's slightly higher on extroversion but but again not always and it's a smaller difference if it is one

Starting point is 02:05:00 and then uh what's the other one can't you just openness yeah openness slightly higher for women as well or no difference what's the explanation for why those would be the case uh well i 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 fact that men take greater risks than women. They're more risk-takey. I think that that evolved because that is about trying to propel yourself up the status hierarchy.

Starting point is 02:05:41 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 yet the flip side of risk-taking is to be more self-protective. part of that is to be more prone to anxiety. The function of anxiety is the same as the function of the turtle shell. It's to protect yourself. It's about protection. So I think that's why women are more neurotic.

Starting point is 02:06:06 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 aggressive, more pushy, and that evolved, like we've discussed, to 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,

Starting point is 02:06:35 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 that seems to be more common in women than men. What about the people versus things divide? So that's an interesting one, right?

Starting point is 02:06:59 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,

Starting point is 02:07:21 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 career-related interests, found that in 53 out of 53 nations. Another one had half a million people and found it an 80 out of 80 nations.

Starting point is 02:07:56 Wow. 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. And this has been around for 100 years? Yep. Yeah. First documented in 111. 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, and I always find that pretty

Starting point is 02:08:17 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. Yeah, yeah, yeah.

Starting point is 02:08:32 But it's there and very consistent. And there's been some deliberate effects, attempts to try and close it as well. Indeed, and they're ongoing, and it just doesn't seem to, doesn't seem to budge, really. Yeah. It's interesting that the soft bigotry

Starting point is 02:08:45 of male expectations happens with get more women into STEM as well. Yes, yeah, indeed. as opposed to get more men and to traditionally female dominant, exactly, exactly, but, you know, Richard Reeves, who has been on the show, right, and that he's trying to get more men

Starting point is 02:09:01 into those kind of professions. 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. Agreed. And if you look, I'm going to guess, that if you look at the gender equality paradox,

Starting point is 02:09:22 you're going to find that in more gender equal nations, fewer women end up going into things-based roles. Yep. And more men go into things-based roles. That is exactly right. Yeah. And just the interest in it gets bigger in those cultures as well. Regardless of what you do.

Starting point is 02:09:38 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. Yep, exactly. And both expand. And it's interesting. Now, I think that you're right that it does reflect the soul. of vaguerary of male expectations. I think people who want to close those gaps

Starting point is 02:09:54 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. But that doesn't change the interest. It doesn't change the interest. I mean, some people are interested in things because I went to university and did business.

Starting point is 02:10:10 Yeah. Because I thought I could get a job in it. Yeah. So I became interested, but it was a very transactional type of interest. 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? You know, not know people. It might depend.

Starting point is 02:10:31 I would say that in a pretty wealthy society that more men than women do that. Now, and 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. But you get some in high inequality, and high poverty environments. You get some really interesting outcomes. You've seen Candice Blake's work on the female beautification? I have, yeah.

Starting point is 02:10:57 Remind me the details. They analyzed, it was either Instagram posts or tweets 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 beautification. And supposedly the proposed mechanism for that is when you see not only how high you could climb

Starting point is 02:11:16 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. It's cool research that right. Yeah, 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. You've seen the environmental security hypothesis as well about men are more attracted to bigger

Starting point is 02:11:45 women in times of poor economy and more attracted to skinnier women in times of good economy? Yeah, it's interesting. And that does seem to be pretty good data on that. I am not 100% persuaded of the evolutionary arguments for it, though.

Starting point is 02:12:01 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. 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 feast and famine,

Starting point is 02:12:18 feasts and famines, I'm sure we did have that, but were the feast periods big enough that people were actually getting big. I mean, my impression is that Hunter Gatherers that just didn't really get big enough that they would have been selection. It would have been very, very, very rare. Exactly.

Starting point is 02:12:31 It would have been almost impossible indeed. Before what, 13,000 years ago. Yeah. It would have been almost exactly impossible definitionally because you could only eat what you could carry. Exactly.

Starting point is 02:12:44 There was no surplus. at all. That's interesting. So I sort of feel like it couldn't... We can fucking grill him about it. We can talk about that, yeah. Because he's a fan of that, right? Yeah, he is. Well, he likes the sort of behavioral ecology approach to things.

Starting point is 02:12:56 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. Yeah. And I do agree with the general principle that, that we've evolved to respond to the ecology. I'm just not sure in that case, it could have evolved because of there weren't, you know,

Starting point is 02:13:23 fatter people around the place for long enough. What about cognitive abilities? Is there a sex difference? That's, if anything is, I would say it's probably the most controversial topic that I deal with in the book. Let's bury it two hours into the episode. Yeah.

Starting point is 02:13:41 So there are some. I guess a few things to say to avoid, try to avoid getting canceled. It's 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.

Starting point is 02:14:09 And that is true. Some of them have, some of them have, but there are some IQ tests. To offset the sex difference? 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.

Starting point is 02:14:42 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 in the samples than the low IQ women bringing down the female average. Because we do have a higher variance. Yeah. 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.

Starting point is 02:15:07 More male geniuses and more male retards. 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 get the advantage to women.

Starting point is 02:15:36 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. That's cool. So no average differences in IQ. Where you do find differences, they're just as likely to favor women as men.

Starting point is 02:16:02 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 their differences are small so the personality 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 a hundred years as well there's there's tons and tons of data on it

Starting point is 02:16:38 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

Starting point is 02:16:53 just due to socialization. What about physical health? 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. than women more prone to heart attacks in particular, at least among, like in 50s and 60s,

Starting point is 02:17:14 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

Starting point is 02:17:43 high rates of death during childbirth. So we drew the short straw there. Unix in the Korean Chosen dynasty lived longer than intact males of identical social standing, demonstrating that testosterone has a direct biological cost to male lifespan. 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 average difference in lifespan between men and women, and would extend men's lifespan, and that is castration. It's got to be castration before you hit puberty, though. So, you know, sadly enough, if anyone wants to take

Starting point is 02:18:25 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. If male mortality rates were lowered to female rates, Randy Nessi, who did the evolutionary medicine studies, calculated we would save more years of life than if we cured cancer. Male mortality were at female rates, we would save more years of life than if we cured cancer.

Starting point is 02:18:55 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. 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 life 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

Starting point is 02:19:26 ways are guys. And 90% of people who risked one's life to save a stranger are also guys. 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 loses. Yeah, exactly. And because men do more of that risk taking, I mean, that's one of the reasons I think that, um, that you get more males and females will start a business that does really, really well. And people focus on that and they think it's unfair. I'm going to guess more will go bankrupt too. 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 like to fail because they take bigger risks.

Starting point is 02:20:06 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. Yeah. Risks doesn't just cut one way. 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. And that's my approach to just a lot of gender gaps in general, right?

Starting point is 02:20:38 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. You know 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. Yeah. What you end up with is actually a world in which there's more likely to be resentfulness and you need to do more compensation on the back end because people have made decisions under

Starting point is 02:21:20 imperfect information. 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,

Starting point is 02:21:36 of overstating the extent to which gender gaps in occupations are due to bias and barriers. You know, 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,

Starting point is 02:22:00 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

Starting point is 02:22:32 to try to eliminate the gaps. 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,

Starting point is 02:22:52 it's not undoing past injustices. It is just adding to the additional injustices. Exactly, exactly, and reverse reverse ones. And then that can create a 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, have these gaps in STEM, more men than women go into it,

Starting point is 02:23:16 and it's just because STEM is just riddled with sexism, is 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, this effort to try to fight it could actually be, you know, create the reverse. You touched on it earlier on. What about differences in mental health? Mental health.

Starting point is 02:23:38 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. So, sciopathy, more likely to be psychopaths. What else is there?

Starting point is 02:24:11 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 the same, across cultures it's about the same frequency of both sexes. What's your explanation for why we would have these differences in mental health? Well, with the depression and anxiety, I think that's just a side effect of the neuroticism sex difference.

Starting point is 02:24:38 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 the way that is more adaptive for males because of the higher maximum offspring. a 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 disorders. I think that there is sort of non-adaptive or actually maladaptive of byproduct of a 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,

Starting point is 02:25:34 and I don't think there is 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

Starting point is 02:26:19 that they mean. I think going through all of this, doing all of the research, obviously you've been deep in this for a long time. Yeah. And then doing the book, what happens, 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? It's a good question. And I think it's a particularly good question because we're always focusing on the dangers

Starting point is 02:26:44 of exaggerating sex differences and moralizing 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, I think that there are also problems with doing the reverse. I think there are also problems with minimizing sex differences and denying them. So one thing is that just as in exactly the same way that some people who exaggerate and moralize sex differences, they try to push people into traditional gender roles. People who deny the differences or massively minimize them,

Starting point is 02:27:16 they're in danger of trying to push people out of gender roles. So kind of replacing one gender straight jacket with another unisex gender straight jacket, or like a maybe reversed, gender role reversed, straight jacket. And now we've actually touched on another of 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,

Starting point is 02:27:41 that we discussed. Other problems with minimizing sex differences is that there are certain physical health problems and mental health problems that so not only did the frequency of different problems differ between the sexes, sometimes the symptoms differ as well. They present differently. Right.

Starting point is 02:28:05 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 and women. Traditionally, doctors and people themselves have been, 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

Starting point is 02:28:45 differently in girls. It's less likely, for instance, to involve repetitive behaviours. 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 like underestimate the centre

Starting point is 02:29:17 which is sometimes goes in the other direction. Yeah, the vast majority of it is bidirectional, right? 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 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... Damn gender equality paradox.

Starting point is 02:29:44 Indeed. When it comes to severe aggression, though, even in the West, men do predominate. But, you know, it's not 100%. And what are the harms of exaggerating sex differences? 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.

Starting point is 02:30:13 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, let people be themselves view, would say, well, that's fine, just let them beat themselves. It doesn't matter. But if you exaggerate and moralize sex differences,

Starting point is 02:30:32 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 exaggerating differences. If you exaggerate the frequency of cardiovascular health problems,

Starting point is 02:30:50 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 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. 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

Starting point is 02:31:17 because you're exaggerating the size of the sex difference. And, you know, like a significant minority of people who suffer depression are men, you know, about a third of cases are guys. So if you exaggerate that difference, you might not be on the lookout for that. Anxiety disorders as well. And social problems, yes, 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, two 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 sex differences.

Starting point is 02:32:00 There's an irony there, however, which is that the sex difference in sexual harassment, sex difference in interpersonal, intimate partner abuse, the people who are most likely to exaggerate that and say it's all men, tend to be gender role progressors, 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.

Starting point is 02:32:32 Fascinating. Steve, you're the best. I appreciate you, mine. 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? Could I plug my substate?

Starting point is 02:32:42 So that's the thing I'm most excited about. Nature, Nurture, Netscher, Newsletter. Dude, I'm a Steve Stuart William 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. Nice, brilliant. Had this one have been out, it would have been in the second one. Thank you. Yeah, your substack rules, and everyone should go and check it out.

Starting point is 02:33:01 I love it. My favorite thing that you do is the Linkfest breakdowns once a month. You just send like 40 or 50 different studies or insights that you've found. You're the best, man. I really appreciate you. Thank you so much for coming to see me. Thank you very much for making this happen. This is great.

Starting point is 02:33:17 I got you. All right. Goodbye, everyone. Later, folks. Dude. Yes. All right. Nailed it.

Starting point is 02:33:23 Nailed it. Nailed it. Fucking awesome.

Modern Wisdom - The Uncomfortable Science Of Sex Differences - Steve Stewart-Williams - #1120

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