Modern Wisdom - #786 - Steve Stewart-Williams - Why Are Differences Between Men & Women Being Denied?

Episode Date: May 20, 2024

Steve Stewart-Williams is an evolutionary psychologist, a professor and an author. If you follow the thread of evolution long enough, you see that humans are simply a product of adaptations. So why are humans so peculiar? Does everything we do have a rational explanation, or are there aspects of our lives and psychology we have yet to understand? Expect to learn how aliens would view our species if they were observing from above, what most people get wrong about understanding sex differences, Steve’s best explanation for the gender equality paradox, why humans have such strange sexual desires, why men tend to insult their intimate partners, how to deal with the discomfort of learning evolutionary psychology, my spicy new theory on dysgenic gene erosion and much more... Sponsors: See discounts for all the products I use and recommend: https://chriswillx.com/deals  Get up to 32% discount on the best supplements from Momentous at https://livemomentous.com/modernwisdom (automatically applied at checkout) Get a 20% discount & free shipping on your Lawnmower 5.0 at https://manscaped.com/modernwisdom (use code MODERNWISDOM) Get an exclusive discount from Surfshark VPN at https://surfshark.deals/MODERNWISDOM (use code MODERNWISDOM) Extra Stuff: Get my free reading list of 100 books to read before you die: https://chriswillx.com/books Try my productivity energy drink Neutonic: https://neutonic.com/modernwisdom Episodes You Might Enjoy: #577 - David Goggins - This Is How To Master Your Life: http://tinyurl.com/43hv6y59 #712 - Dr Jordan Peterson - How To Destroy Your Negative Beliefs: http://tinyurl.com/2rtz7avf #700 - Dr Andrew Huberman - The Secret Tools To Hack Your Brain: http://tinyurl.com/3ccn5vkp - Get In Touch: Instagram: https://www.instagram.com/chriswillx Twitter: https://www.twitter.com/chriswillx YouTube: https://www.youtube.com/modernwisdompodcast Email: https://chriswillx.com/contact - Learn more about your ad choices. Visit megaphone.fm/adchoices

Hello everybody, welcome back to the show. My guest today is Steve Stewart Williams. He's a professor of psychology at the University of Nottingham, Malaysia and an author. If you follow the thread of evolution long enough, you see that humans are simply a product of adaptations. So how have humans become so peculiar? Does everything that we do have a rational explanation

or are there still aspects of our lives and psychology that we have yet to understand? Expect to learn how aliens would view our species if they were observing from above, what most people get wrong about understanding sex differences, Steve's best explanations for the gender equality paradox, why humans have such strange sexual desires, why men tend to insult their intimate partners, how to deal with the discomfort of learning evolutionary psychology, my spicy new theory on dysgenic gene erosion, and much more.

Steve is potentially one of my favorite authors of all time. And his book, The Ape Who Understood the Universe, is in my list of 100 books that you need to read before you die, and completely changed my worldview on an awful lot of things and he is fascinating and his work is brilliant and this is just so much fun. I've been waiting a long time to bring him on the show. He is an underground hero. I'm confident that over the next few years you're going to see so much more of him. Really, really happy to have brought

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This episode is brought to you by Surfshark VPN. Protect your browsing online and get access to the entire world's Netflix library for less than the price of a cup of coffee per month. If you use a public Wi-Fi network like a cafeteria or a library or an airport regularly that internet admin can see all of the data going back and forth between your computer and the internet. Your internet service provider is selling your data to companies that target you with ads and phishing websites are trying to steal everything from you at all times. All of this is fixed with a VPN and it is available across

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How would an alien scientist view our species, do you think? Well, that's how I start the book, right? So I start, like the framing device for the whole book is the idea that how would an alien scientist, if it came to the earth to try to explore these crazy creatures, human beings, what would it make of us? And the short answer is that it would be mystified by us. So I imagine that this is an alien that doesn't have sexes, it doesn't have, therefore, it doesn't have sex differences, doesn't have families, doesn't have any of this it doesn't have, therefore, it doesn't have sex differences, doesn't have families, doesn't have any of this kind of stuff that we take for granted. And so it would be mystified by the fact that we are divided into two basic types,

that those two types differ from each other, that we fall in love with each other, that we get jealous for some reason if the person that we're in love with gets involved with somebody else. Um, that we, that we're kind of typically toward our family members than to non-family members, um, that we, uh, that we listen to music, that we have music and art and all these kinds of strange, strange things that don't have any obvious survival value, um, but which we spend a lot of time just amusing ourselves with, uh, so that's the framing device that would find us very weird in many different ways. Yeah.

It's very odd. I think, uh, I've had a lot of conversations about evolution, sex differences, sexual selection, et cetera, et cetera, but talking about culture and the role of culture evolutionarily, how do you even begin to frame that integration? Yeah. And that's a's maybe the big question. And I think possibly that's the thing that the alien will be most surprised about when encountering us.

Because a lot of the stuff, you know, the sex differences and that kind of thing, they're kind of comparable to what we find in other species. But what really makes us unique, I think, is culture. That would be the thing that particularly mystifies the alien, I think. And I think the answer, it's a two-part answer, really, I think. I think the first part is that somewhere along the line, we evolve the capacity for culture. And we're not the only species that has that, but we have just taken it further than any other species. So we evolved the capacity to basically make up tricks and learn tricks from each other. And we have the intelligence, the cultural capacity to do that. And it makes us a kind of open-ended system so that our culture can come off the leash, so to speak.

And then that comes to the second part of the story, which is that once it's off the leash, it starts evolving in its own right, somewhat independently of biological evolution. So biological evolution is about selection for genes. Cultural evolution is about selection, not for genes, but for the elements of culture, which are often called memes. So you can select for different memes and the forces, but the selective forces act on memes aren't necessary. The same ones that act on genes, they can go in different directions. So you can have memetic, memetic evolution going off in completely different directions from what genetic

evolution, my favor, and we can be kind of torn between those two different options. Can you explain the fundamental dynamics of selection for us? In general, selection, yep, sure. So in general, it's about replicators. So it's about entities, light genes, or all light memes that are capable of replicating themselves. And the nature of the selection process is that the replicators that are best at replicating themselves are the ones that are going to increase in frequency within the population. In biological evolution, that's a question of genes, different gene

variants becoming more and more common compared to competing versions of the same gene, competing alleles. In the cultural sphere, it's about different cultural elements becoming more and more common relative to competitors. And basically what you get is you get selection. So like I said, selection for the variants that are best able to replicate themselves. And in the biological sphere, what it does is you get selection for genes that have effects on their owners, i.e. us, that increase the chances that they're going to be put forward into future generations. And that turns us into what I call in the book, gene machines.

So into organisms that look as if we've been designed and look as if our intention is to pass on as many of our genes as possible to the next generation. And just the rationale for that is that if you were a gene and you had an effect on your owner, that meant that you were less likely to survive, less likely to have kids, less likely to help your kin, then you would pretty quickly go out of existence compared to other genes that had the opposite effects, that boosted your survival, boosted your chances of having offspring or boosted the extent to which you helped, uh, relatives. You kind of play a bait and switch, I think six and a half times in the book

where you try to explain what we might be as maximizing machines. And I think it ends up being like modified grandchildren maximizing machines. And I think it ends up being like modified grandchildren, maximizing machines. Can you, can you explain why we're modified grandchildren, maximizing machines? Yeah. Yeah. Okay. So, um, so yeah, I go through a series of hypotheses basically about what

we've evolved to do, what, what human beings are for. So, so the alien would see us, we're like these biological machines, what are these machines designed to do? Let's see if I can remember them all. So the first one is, so I ask, are we designed to, for the good of the species? And I rule that out. It's not for the good of the species. The next one is, are we survival machines? I rule that out because if you were to survive for a hundred thousand years, if you were never to have offspring for instance, then as soon as you actually die, your genes are going to go out of existence as quickly as if you'd lived for 20 seconds.

So then I think, okay, so maybe it's about offspring, right? So machines designed to reproduce, to have offspring, that's a big step closer, I think. But I think that's not quite right either. Because if you had 100,000 babies, but none of those babies survived to have babies of their own, then again, your genes are pretty quickly going to go out of existence as if you'd never had any babies. So like a big jump in the right direction is that where machine is designed to ultimately have grandchildren. But actually I take a couple of steps beyond that as well, because there's also the inclusive

fitness perspective. So then inclusive fitness brings in, okay, so what I've said so far is like it's about surviving and making offspring that had their own offspring. Inclusive fitness brings in another element, which is Kenaltruism, which is that we can also spread our genes by helping our genetic relatives to survive and have offspring and those offspring to have offspring of their own. Yeah. I heard, I had a conversation a couple of months ago talking about twins and twin studies.

And I found it so interesting that if what you're saying is correct, which is basically the level of genetic similarity between us and the kin around us, whether that be children, grandchildren, brothers, aunties, uncles, cousins, et cetera, the closer that it is, the more affinity that we will feel, the higher level of investment that we will feel. And there was a study done that looked at levels of grieving of identical twins, and they found that the level of grief that was felt by the one remaining twin

is potentially, hypothetically, the greatest amount of grieving that anyone could have for another person. Yeah, that's fascinating, right? So people grieve more if they lose an identical twin than if they lose a fraternal twin. It's fascinating. What is that? Is that Nancy Seagals? It was Nancy Seagal. Yeah. Yeah. She came up to me at HBAS. She gave said some very flattering things. And then shortly after I brought her on the podcast, yeah, she's phenomenal.

She is really great. Right. She's got research as well. I think where when twins meet each other in adulthood for the first time, it's like they're separated at birth, grow up separately when they meet each other. Identical twins tend to have more of an affinity immediately than fraternal twins do, even not having grown up with each other or anything. Is that because of, is that postulated that it's because of the visual

similarity that they can quite quickly see or look at how close this person is to me? My guess is that it's that initially, initially as the visual similarity, but then as they sort of interact and get to know each other a bit more, they're likely to be more similar. Oh, we use the same weird brand of toothpaste. Oh, you also drive a tan Chevy eight five. Oh, you also married a woman called Stacy.

Like I know that this sounds to the people that haven't heard the Nancy Siegel episode. This sounds like I'm just pulling stuff out of my ass, but like, this is represented in like data. It's wild, right? There's the similarity between, between identical twins, read apart is just incredible. Yeah, it's wild.

Uh, I wonder whether that means that. Do we have an affinity for people who look like us? I think we do. I think we do. I think we do. Yeah. And I think that that's probably one of the, uh, slightly less nice on the one hand, right, because we're feeling an affinity with these people like us, but there's a dark side to that, of course, which is exactly, that just is one of

the things that makes, uh, I guess, put it back in the cultural evolution, it makes racist memes, uh, easier to accept just cause we do have. And affinity for people like us and the flip side of that is, uh, the, whatever the opposite of an affinity is for people unlike us. Yeah. Disaffinity. I, uh, I wonder whether one of the things that I've been parroting for a little while is we are more prejudiced against people with different accents than people with different skin colors.

Yeah. Yeah. Yeah. Interesting. Yeah. What do you, what do you make of that? Given that we also have my point being ancestrally different skin colors would have been very novel, different accents would have been very common.

Therefore creating a tribal prejudice against different accents has more adaptive sense. But we also have this, they look like us, they don't look like us thing, which might be kind of further away and deeper than the accent stuff. Yeah. No, I think, I think you're right. I think that, um, although we do have that disaffinity for people who look unlike us, it's, it's not so deep that I mean deep that, I mean, we can get past it. And I think the deeper trend

is just a in-group, out-group kind of thing. And it seems to be fairly easy to have people who look dissimilar to ourselves. We can put them into our in-groups pretty easily. And an accent is a good in-group marker, really. So that can trump any effects of physical dissimilarity and often does. Um, so yeah, so the, so we're not stuck with it. So we're not stuck with the, um, uh, the disaffinity for people who look

unlike us, it can be trumped by other things. And I do think you're right about the accents. Um, they do seem to serve as a tribal marker and often more so. Yeah. Yeah. It's very, very interesting indeed. So what do you think most people get wrong when it comes to understanding sex differences?

Uh, I think that that that's a long list of things. Um, I'm working on a new book actually, and it's going to be focused on sex differences. Hell yeah. And I think, so okay, so the two big things I think that people get wrong, and the one that probably people are going to be expecting me to say, and that I do say in this new book, is that people often think that there are no sex differences or that there are no, that there's no innate push toward sex differences. To the extent they exist at all, they come almost solely from culture. I think

that's one big mistake. But I do also think people make the opposite mistake as well. So there's also a tendency to exaggerate the magnitude of human sex differences. I think both of them are mistakes that people fall into. I think these days probably they more often fall into the first mistake, the minimizing and denying mistake. But people do make both and I think both potentially cause problems. Is it a narrow tight rope to walk along to actually get the amount of sex differences right? Is it?

I think it is. I think it is. I think it is very, it is difficult because I think people, it's just very easy to, to swing to one extreme or the other. Um, and then if you, okay, if you just sort of start opening the door, okay, there are some evolved sex differences. And then I think we may be quite easily spin to the extreme of thinking that they're massive and that they're huge and that they're huge. And in some species they are, but I think that where, as mammals go, we have relatively

modest sex differences. And actually that's another thing I think that the alien would be puzzled by. It would say, okay, we've got these sex differences in this weird species, but they belong to the big group called mammals. And in a lot of mammals, the differences are much larger. What are your favorite psychological sex differences in humans? Um, let me think. Okay.

So let me start with the one I think is the biggest one, the single biggest, um, psychological sex difference. I don't suppose you can guess what it might be. Desire for sexual novelty. That is, that's usually about a medium effect size. Um, so about 0.5, maybe a bit bigger. The one I'm thinking of is much, much bigger than that. Fuck.

Uh, I, I give up. Tell me. It's, um, it's one that as soon as I say it, you'll, you'll recognize it and you'll recognize that it's huge. I think we take it so, so obvious to us that we take it for granted and don't think of it, um, it's the fact that the vast majority of men are primarily sexually interested in women, and the vast majority of women are primarily sexually interested in men. So it's interesting. That is a massive difference. And that does show that natural selection can

create huge sex differences in our species. And then most of the time it creates sex differences that are nowhere near that magnitude. Um, it's interesting though, if you look at, um, summaries of sex differences and evolved sex differences, very often that one is just left out. And I just think it's just cause we take it for granted so much that that's the case that we don't even really think of it when we're listing them. That's like the physics of sex.

Yeah. Yeah, yeah, physics of sex. Yeah. Yeah, yeah, yeah. Yeah, exactly. Um, and it is a clear, there's a clear evolutionary rationale of course, for it as well, um, other ones on that list, uh, would be the desire for sexual variety. Like I said, it's a medium sex difference. Uh, the desire for casual sex is a large sex difference. The desire for casual sex is a large sex difference. That one's actually larger usually than the desire for sexual variety. Sex differences and aggression,

face-to-face aggression and violence in particular. That's another big one. Sex differences and parental inclinations would be another. Yeah. It's interesting. Oh, what's the one in, tell me about jealousy. Sex difference and jealousy, this isn't a huge one, but that is the fact that most, so men in general on average are more upset than women about sexual infidelity. So if their partner gets, So if you ask people, okay, so imagine your partner, you're in love with your partner, your partner gets involved with somebody else, which would upset you more? Would you be more upset if they had sex with somebody

else or would you be more upset if they got emotionally close to someone else, kind of fell in love with somebody else? And obviously both of those things are upsetting to most people, but more men than women say that the sexual infidelity would be more upsetting to them and more women than men say the opposite. They say that the emotional infidelity would be more upsetting to them. Yeah. Well, I mean, how many times has there been some on-street interview? I even remember this from back in school, I think, about would you rather that your girlfriend kissed someone else or told you that they were in love

with someone else or whatever, and just this asymmetry in terms of what it is that we're jealous about. So can you run through, can you go a layer deeper and talk about how those two types of jealousy are more and less adaptive? Yep, let me start with the commonality though. So just the, I think the main function of jealousy are more and less adaptive? Yep. Let me start with the commonality though. So just the, I think the main function of jealousy for both sexes, it's part of our pair bonding psychology.

So we fall in love with each other, but we also had jealousy. And I think that both sexes, the function, the main function of that is to protect the pair bond. Um, pair bonds were adapted for us in the past as a setting for having kids and rearing kids. And so we've evolved a psychology to kind of protect them. The differences though, the main difference for men compared to women is paternity uncertainty. So David Buss has a great way of putting this. He says, there's never in the history of the world been a case where you have a woman who

gives birth to a kid and then thinks, is this my kid or is this some other woman's kid? I don't know. Whereas for men, if their partner gives birth, it's almost certainly their kid, but there is a possibility that it's not their kid. And any guy that ended up investing in a kid that wasn't his own biological kid, all the paternal effort that he puts into that kid, he's putting it in effect into the genes of another guy. And so any trait that would have come along that decreased the chances that that would happen,

that trait would have a good chance of being selected. And jealousy, I think, is one of those. So the kind of jealousy that makes the guy keep a kind of wary eye on his partner and on the good looking next door neighbor and to take action. If they start, or the guy at work, maybe she keeps talking about that guy at work, he starts getting a bit worried about that, maybe takes action to try to make sure nothing happens. Maybe he's a bit more attentive, maybe he handles it in a nastier way. But because paternity uncertainty is the main issue for guys, well, paternity uncertainty is facilitated by sex,

not just falling in love, but sex, the sex act itself is what leads to somebody having somebody else's kid, right? So that's the evolutionary rationale for why guys are particularly focused on that. With women on the other hand, emotional infidelity, it's a big deal. Obviously, it's a big deal to people. A woman doesn't want her partner sleeping with somebody else and she's going to be upset about that Obviously, it's a big deal to people. A woman doesn't want her partner sleeping with somebody else. And she's going to be upset about that. And it's a common cause of the end of relationships. But evolutionarily speaking, it doesn't have quite the catastrophic consequences that it does for guys. What can do though is if she has a nice pep on and they have a kid,

and I'm thinking sort of ancestrally more, you have this investing dad. If he would have fallen in love with someone else, then that would increase the chances that he's actually just going to split up the pair bond and go with somebody else. And that would make it a lot harder for her to raise the kid. It would ancestrally increase the chances that the kid wouldn't make it for a start, but also just just sleeps with somebody else. So that's the evolutionary rationale for why she might be more focused on love and fidelity as opposed to sex and fidelity, sexual and fidelity. What is your favorite explanation for why women have concealed ovulation then? Well, I think it's the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, opposed to sex and fidelity, sexual and fidelity. What is your favorite explanation for why women have concealed ovulation then?

Uh, I'm not sure. I'm not sure I have one. It's a really interesting question why we do have concealed ovulation. Um, I've read the different theories and I don't find any of them hugely persuasive. So, so I'm not completely sure. find any of them hugely persuasive. So I'm not completely sure. Let me highlight one though, in particular that I guess is, I think maybe overlooked a little bit. And that's the idea that rather than ovulation being deliberately concealed, so to speak, deliberately by natural selection, that actually the default is just that you don't advertise it. And then in some species you have it advertised, you have it advertised

in chimpanzees and baboons and that kind of thing. They have the kind of swellings that they do when they're in estrus. But we just don't have that. So there's been no selection for advertising it as opposed to there being some definite adaptive rationale for concealing it. How interesting. Yeah, that is, uh, I mean, I've, I've read a ton of theories as well about it. Is it that by concealing ovulation, no one man knows when, or no one male knows when

him and that particular woman had sex. So therefore is this child mine? You kind of get this like dispersed male parental investment thing potentially. Is it that by making it more difficult to work out when you are fertile as a woman, that it increases the amount of sex that you need to have with your partner? Which means that you increase pair bonding, which gets both guy and woman to be more likely to stick around for this fucking infant that needs 10 years of, of looking after before it can be

functional and independent on its own. There was one where I think Macken or William told me about it where it was an ever sort of escalating battle between the woman to work out how not to get pregnant and the system on telling her how, when she was able to get pregnant. So it was like reverse birth control in a way. And the system on telling her how, when she was able to get pregnant. So it was like reverse birth control.

Yeah. Yeah. Um, of those three, I think, I think the second of those, I think is the one that I, um, that rings truest to me. I've never been particularly persuaded by that last one, but yeah, so I'd sort of either, I'd either go, I think if I had to bet on it right now, I'd either go for the non-adaptationist, We just didn't evolve to advertise it. One or the second one that is to facilitate pair bonding. And males and females spending lots of time together all the time rather than

just when the female is ovulating. Yeah. We're one of a very small number of species that have recreational sex. Right? Yeah. Yep. I think so. Um, bonobos, I guess would be, would join us in that small club.

Uh, bonobos, I think have quite a lot of sex and just with everyone in the group. And with like rolled up handles of buckets and anything else that they can get their hands on as well. Yeah. Yeah, indeed. And I guess, I guess when you think about it that way, that dogs actually are quite um, prolific in terms of the range of sexual interest that they have. Um, another spicy one, what do you make of the, uh, women purposefully starving themselves and making themselves anorexic is a vestige of ancestral birth control.

Uh, interesting. Um, I think that's, I think, I don't know that does, that doesn't strike me as immediately particularly likely. I don't know. That doesn't strike me as immediately particularly likely. I think I prefer some of the hypotheses that people normally actually have come up with. His argument is that it's not an adaptation and it's not an extension of an adaptation, but it's just a weird kind of cultural byproduct of just sort of status seeking, intersexual competitiveness that you get. You get within each sex, you have competition in different ways of like attracting a mate and that kind of thing. And it just seems to have, in some societies, wealthy societies have latched on to being super thin.

And that's not adaptive, but it's just taken to an extreme and a minority of people. And I think one reason I think that's more likely than an explanation like the birth control explanation is that it's only really found in wealthy societies. It's not typical of most cultures. It seems to be a weird quirk of the kind of societies that we live in today, rather than something that's found in ancestral times. Yeah. I learned the environmental security hypothesis a couple of months ago. Have you heard this one? Yeah. What's that? I'm not sure. Male preference for female body size varies based on economic conditions.

Preference for female body size varies based on economic conditions. So during times when the economy is more uncertain, men prefer, uh, follow women. And in times when the economy is safer, they prefer thinner women. And they've done studies where they ask men to rate the relative attractiveness of women of various body sizes, uh, before and after they eat food and the post eating food for men results in a, uh, thinner woman being preferred. Right, right, right. And then when they were hungry, they prefer. Look at how robust she is.

Look at how many famines she could handle. Look at, look at how many depressions and high interest rates she would be able to put up with. Interesting. And what's the name of that? So I have heard that. Environmental security, environmental security hypothesis. Hypothesis.

Yeah. Okay. Cool. Yeah. That's interesting. Talk to me. Okay. So just looping back to the sex differences thing, what do you say to the people who would

go, that sounds fine, Steve, but how, how do we not know that this is all just due to socialization? Well, I think that's a good question, a perfectly reasonable question. And I think the first thing I'd say is that socialization does play a role. So I certainly wouldn't be arguing that these differences had nothing at all to do with socialization. One line of evidence that they do is that the magnitude of the differences is different across different cultures and it's different within the same culture at different times. So for me, the question is really, how do we know that it's not just socialization? And I think that there are various lines of evidence that pretty strongly, very strongly

actually I think, do suggest that for kind of sex differences that I named earlier, that they're not just down to socialization. So I lay out sex in the new book. See if I can remember what they are. So one is that they tend to be really stable over time. So they persist within a culture, even when the culture changes quite a lot. Sex differences and mate preferences, for instance, survived right throughout the 20th century in the US, for instance. Even though there were quite radical shifts in the culture at that time, there was the sexual revolution and the feminist revolution and sex differences and mate preferences just persisted throughout that time. Sex differences and the preference for casual sex as well, they persisted throughout that time. You find them, a lot of them appear quite early

in development before it's sort of plausible that socialization could be involved. The sex difference in aggression, for instance, appears really, really early. As soon as kids can basically move around and be capable of aggression, you see sex differences there. And also a lot of sex differences either appear in the wake of puberty or they get bigger in the wake of puberty. So the developmental timing there is not 100% proof, but that suggests as well that it might be having an evolutionary basis. The third one is that often sex differences persist in the face of culture. I think the usual story is, okay, so you have these differences and they're created by culture, but often they persist even when the culture is pushing in the opposite direction.

So aggression is a good example of that actually. There's a sex difference in aggression, males on average, I don't need to say the difference, the direction of the difference, but males are more aggressive. And people might say, well, that's because we encourage males to be more aggressive. But actually if you tabulate how often people are saying,

don't be aggressive to boys and don't be aggressive to girls, they're saying a lot more to boys. They're discouraging boys from being aggressive a lot more than they are discouraging girls. Not because they want girls to be more aggressive, but just because boys are more aggressive and aggression is a problem and they try to clamp down on it. And they clamp down on it. In most cultures, there are some where they actively encourage it, but in most cultures, they do clamp down on it in most cultures. There are some where they actively encourage it, but in most cultures they do clamp down on it. But despite that, you still have that same sex difference

persisting anyway. So that was three, right? Yeah. Four is hormonal, especially prenatal hormonal associations that you have between levels of testosterone in the womb in particular, and then the emergence of traits, male typical and female typical traits later on. So there's a condition called congenital adrenal hyperplasia, where you're exposed to very, very high levels of testosterone,

other androgens in the womb. For guys, that makes no difference because they already have very, very high levels. But for women, for girls who are exposed to them, the high levels, it does have a big effect on them and it sort of masculinizes their behavior in a lot of ways. They're more prone to aggression, maybe they have more male typical preferences. They sort of shifted in the male direction. They're somewhere in between the female and the male norm as a result of testosterone. Number five is cross-cultural universality. So if these things, if the kind of sex differences we're talking about were just due to culture and culture alone, we'd expect them to vary quite a bit across cultures. In some cultures, you might have men being more interested in porn, for instance, and women being more interested in romance novels. In other cultures, no sex differences

in either direction, they both like or dislike them just as much as each other. In others, you'd find it reversed. In some cultures, women are more into porn and women hire prostitutes and men are the majority of the prostitutes and men are reading the romance novels. And of course, you don't find that. You find that these differences are very, very consistent across all, depending on the trait, every single culture where we've looked or the vast majority. And it's a lot easier when you find that to explain it in evolutionary terms than in terms of purely sociocultural ones. And then the last one, maybe the most persuasive one is that you find the same kinds of sex differences in other species as well. And you don't find them in all other species, but

differences in other species as well. You don't find them in all other species, but importantly, you find them in other species that are subject to the same selection pressures as our species is. What do you mean when you say that? Well, the main selection pressure that creates most of these sex differences is the sex difference in reproductive variability, or in other words, the sex difference and the maximum offspring number. So basically men and a lot of male animals potentially can have many, many more offspring than any female, even the most successful female can have. The average has to be almost exactly the same as long as you have an equal sex ratio. The average for both sexes has to be the same, but the variance can be greater

for males and females and often is. And when you have that, when you have the greater variance in males, that means that there are more males than females having no offspring at one end. But then the important end is that you have more males than females having tons of offspring. And where that's the case,

you have stronger selection of males, the traits are going to drag you up toward that end of having more offspring rather than fewer. So different selection pressure from what you have in females. So it selects for things like aggressive status seeking, stronger desire for status, a stronger desire for multiple sexual partners so that you can end up with multiple offspring for status, a stronger desire for multiple sexual partners so that you can end up with multiple offspring or would do in our ancestral past when we didn't have birth control and the like. All those kinds of traits, lower level of parental investment so you can spend more time seeking mates. All those kinds of traits are selected and not just in our species, but just in any species. We had greater reproductive variance among the males and the females.

Um, and, and that's the, that's the key thing. That's the key line of evidence is that we had the greater reproductive variance, that's where you'd expect these sex differences, that the theory is correct and that's where you do find sex differences. Yeah. So you've had your hypothesis proven by the world around you. Exactly. Yeah.

But by many different species. And it species and it's very cool, right? Cause there are some species where you don't find the sex difference and reproductive variance and those species, uh, you don't really find much in the way of sex differences. So you find you have, you have what I call monomorphic species and in a few that's, it's actually flipped into reverse and females are greater variants. And then all the usual sex differences are turned on their head and the females more aggressively seeking mates and beating each other up to try to get mates. And in Jucanas, that's a North American shorebird for instance, the Jucana,

basically Jucana females try to put together a little harem of males and they have a bunch of different nests and they try to get these little males, these choosy little, non-aggressive little males. Shoes on the other foot now, women. How do you like that? My students do actually love this when I talk about the jocanas and I think it's for exactly that reason. It feels like the shoes on the other foot. Yeah.

Eat some of your own medicine for a while. My favorite one, I think, I think my, I learned this from David Geary. Yeah. And he was talking about, um, the preference that males have, even, uh, male chimpanzees, other sort of primates, um, for reciprocal motion, reciprocating motion, um, in toys. So, you know, you would think the reason that young boys like trucks and young girls like dolls and fluffy things is that some socialization thing. And he was like, you can give this to close sort of species relatives

and the boys will pick that. There's something about the male brain, which loves that. I'm going to guess that you've looked at this as well. Yeah. Yeah, I have. And I think it's fascinating, right? You find that in vet monkeys and, uh, macaques maybe, I think. Yeah.

Yeah. Yeah. It's, it's incredible. Right. Cause I, cause I have to say like those toy preferences before seeing evidence like that, it does seem pretty plausible. Like what, what could that have to do with evolution? It's much more remote than things like aggression and sex drive and

interest in casual sex or all that stuff is much more, much more plausible. I think basically. Well, what would be the adaptive reason for you wanting to have a toy that goes back and forth or you wanting to hold something that's soft and fluffy, but then you actually need to think sort of five steps down the line. Well, this reciprocal motion is your spatial orientation starting to lock in a little bit more because at some point in the future, you might need to throw a stone and hit a snake or throw a spear and this, what are you doing?

Well, you're kind of learning to keep something alive as a girl. You're, you're learning to be able to care and nurture, to look something in the eyes and to be able to work out whether it's still alive or dead. And then, you know, you roll the clock forward and you look at like Joyce Benenson's work, what is it that children in primary schools are doing? Children in primary schools. If you're a young set of boys, you're doing warfare. You're fighting Indians or aliens or whatever it might be.

And if you're girls, you're playing that or nurse or doctor, you're keeping something alive. It's all interpersonal and yeah, whether it's macaques or vervet monkeys or toddlers, the sort of rules seem to be very similar. Yeah. Yeah. It's amazing. Right.

And, and like with the, with the monkey research, the macaques and the like, the bit of that that I find most plausible is the caring for dolls, caring for little things like that. I think it's pretty clear an offshoot of a greater parental inclination in the females than the males. Yeah, but it is really interesting, right? And you know, the toy differences, it's like I was saying, it's hard to think of the evolutionary rationale, but despite that it's among the largest sex differences other than sexual orientation that there is, it's a really big sex difference.

Yeah. Strange. Right. Well, I saw David taught me about that study where you can raise, you can, you work out whether or not a child has been raised in a gender conforming or a gender nonconforming household. Then you bring the children into the lab and you let them play with any toy that they want.

You can play with trucks as a girl, you can play with dolls as a boy. And whether you've come from gender conforming or gender nonconforming households, you still see the same sex. Yeah. Yeah. Yeah. It's great. Right. And, and I think the big difference there is that, um, the still see the same sex difference. Yeah, yeah, it's great. Right. And I think the big difference there is that, um, the ones in the gender

nonconforming household are just more tolerant of kids who want to be gender nonconforming. Yes. Yeah, that's nice. That's a nice effect. All right. Um, your substack apart from, I'm just blowing you the entire, entire episode. Uh, your substack is also fantastic and everybody should go and check that out.

But what happened with the attempted debunking of the man, the hunter theory? Please tell everyone the gossip. Yeah. Yeah. So that's one of my sub stack posts, right? As, um, it was a paper last year, um, by Abigail Anderson and colleagues where they basically tried to debunk the idea, they called it the man the hunter idea by which they meant the idea that in hunter-gather conditions,

men did most of the hunting and women did most of the gathering. And there was a pretty clear division of labor. And I remember when I read that, I thought, I think that's quite unlikely, just on the face of it, it's quite unlikely that anthropologists studying this issue for more than a century, and not just male and female anthropologists have looked at this issue, is it really plausible that they have just kind of hallucinated this massive sex difference and are they just muddled about this conclusion that men do most of the hunting, especially most of the big game hunting and that women either do basically none or they just do a little bit and more often small game hunting rather than big game. So my thoughts doesn't seem very likely. And then this pre-print has come out

in the last couple of months, which has more systematically gone with that intuition and made what I think is a very strong case that they weren't right about that. That they were wrong about this idea that hunting is a lot more even than we had thought. And what they seem to have made a number of mistakes. There are coding errors in there where they were

coding societies that didn't have female hunting as ones that did. That was one error. Another one was that they only included a relatively small subset of the available societies for which we had data. And there were plenty of others that they could have included that would have been, which would have met their criteria, but which they didn't include. And when you include those as well, they tend to show the traditional view that meant to most of the hunting. And they didn't show frequency or like density of hunting as well.

Right. It was like a single instance of female big game hunting. You know, you, you, you take your wife to work with you one day and that kind of counts as her being there for a 50 year career. Yeah, and that's a way that you can make sex differences seem really, really small, is if you just have a yes, no format.

Like I've seen studies where they say, for instance, that interest in pornography is pretty even between the sexes. Cause if you ask people, have you ever watched it? Hardly any difference. But if you ask people, have you ever watched it? How's the any difference? But if you look at frequency, the difference becomes huge and it's exactly the same for hunting. Fuckery, fuckery everywhere.

Steve. So I, um, I wrote a little theory off the back of this. You have this really sort of lovely breakdown, which is, uh, the male default, right? There's this assumption that male behavior is desirable in some way. And I call this the soft bigotry of male expectations. Nice. I like that.

That's great. Which I think fits of male expectations. Yeah. For instance, you make this really great point, which is no one is asking. Everybody was asking why are women not doing so much big game hunting? No one was asking, why aren't men doing more berry collection? And there is implicit in, you know, what is I think supposed to be a, not even thinly veiled,

completely transparent sort of pro-feminist, boss pitchy, moving forward kind of text. Well, are you not implicitly derogating the role that women mostly took, which is that of being the carer, that of being the berry collector and the nut collector and the tubal, tuba connector and all of that. Exactly. It does crucial tasks and equally difficult tasks in their own kind of way. And they're just considered to be not as valuable implicitly.

Lesser. And, and yeah, exactly. They are implicitly seen as lesser, even though, um, yeah, even though it's, uh, supposedly a pro-feminist thing, you know, you can read, you can see in a, it does have a sort of, um, negative judgment about the things that are more common among females. I mean, there's some things so, so satisfying about people that are self-righteous and self-aggrandizing, uh, sort of falling on their own sword and, you know, reading that, I'd be lying if I said it didn't give me a big sort of kick of satisfaction when I read your takedown of it. Nice. I'm just going to write down, just writing down soft bigotry of male expectations. I like that. Oh yeah. Okay. So what are your best explanations for the gender equality paradox that we're seeing?

So the gender equality paradox is the quite surprising counterintuitive finding that for a lot of traits, sex differences seem to be smaller rather than larger in less gender equal nations. So basically as nations become more gender equal in terms of who's involved in politics and equality under the law and equality of access to education, et cetera, as they become more gender equal in those kind of ways. Traditional sociocultural theories and social role theory would predict that the sex differences would get progressively smaller as gender equality increases. And for a few traits they do, but for a lot of traits, strangely enough, it's the other way around. So gender equality increases for a lot of traits, strangely enough, it's the other way around. So gender equality increases and associated with that are larger sex differences rather than smaller ones. And I find it, I just think it's a very surprising finding. I would have, even accepting that there was

an innate contribution to a lot of sex differences, I still would have thought that more patriarchal societies where men and women are treated very, very differently and they're expected to do different stuff, I would have expected that would amplify the sex differences and make them even bigger than the innate push. But often it's the opposite and they actually get smaller. And then the question is why on earth is that the case? And I guess the first thing I want to say about that is that I don't think it's fully known. But my best guess is that what's happening is societies that are more gender equal, it

comes with a cluster of different cultural level variables. So they're more gender equal. They also tend to be more individualistic on average. It also tends to be correlated with wealth, greater human development of the societies, that kind of thing. And where that's the case, people have more freedom to pursue what they most want to do, pursue the things that interest them most and nurture their own individuality. And the more people can do that, the larger that individual differences get, but also the larger the average sex differences get as well. Yeah.

I mean, it's so odd, like from first principles to think that that would be the outcome that people are going to get. Exactly. It is so strange. What do you, have you got any idea what's actually happening with men and women in STEM at the moment? Um, I, yeah, we've got, I've got a few ideas about that. Um, the first thing is, so, so we often hear that there are more men than women

in STEM and depending on how you define STEM, that's not actually necessarily the case. So if you include the health sciences, it's actually pretty even, at least among younger generations, it's pretty even how many men, how many women go into STEM overall, really, really close. But the difference that everybody notices and worries about is the fact that more men than women go to certain fields, fields like physics and engineering and mathematics. They've got more going to philosophy as well, that's not STEM, but these are the ones that people worry about. Not so worried about the flip side of this, not so worried about the fact that more women

than men go to the health sciences and that kind of thing. And I do wonder if this is another example of the soft bigotry of male expectations is that people kind of assume that anything that tilts male is superior and therefore that we need to get women into that and kind of implicitly downgrade the importance of the kind of areas in which more women than men go into. Either way though, there's an interesting question about why those differences are there. An interesting question, and also it's quite a controversial question or at any rate, there are controversial answers to that question. So the main explanation that people like to give is that it's largely a product of discrimination and sexist socialization. And so I just want to point out that I agree that that's part of it, that part of the story. I would just say, I just don't think it's the whole story though. I think that some of the differences that we talked about already, actually the difference in interest in

people versus interest in an object plays into it as well. And those differences, they appear very, very early on. They're found across cultures. In fact, it's a massively consistent sex difference actually. There's one study I saw which I think had about 200,000 people in it, 53 nations and every single one of those 53 nations, they found that sex difference. Then another study which David Gehry actually was involved in, they had half a million participants in the study, 80 nations, and 80 out of the 80 nations, you found that sex difference. So it is a huge sex difference. Goddamn patriarchy going global. Patriarchy everywhere, yeah, exactly. Except that in less patriarchal nations,

some of those differences are larger rather than smaller. You do get a gender equality paradox for the sex difference in objects versus interests in people, which is fascinating. And it just seems perfectly plausible to me that those sex differences and interests are part of what's shaping the sex difference in which areas people go into, which occupations. And actually I say, I want to put this more strongly, I think that it would be implausible to think that those interests are not part of the story. Like how could they not be? If people are freely choosing what they want to do, they have these interests. Even if we just ignore the question of where those interests

come from, they do have those interests. It must be part of the story, feeding into the difference in what's called occupational segregation. That's putting it too strongly, I think that phrase, because it's not segregated. Occupational segregation, what a great occupational apartheid. Except that the differences are much more modest than that. There's no field where one sex is present and one sex is absent. There's just, uh, you know, going away from a 50 50 sex ratio. So there's, there's even where women are least represented, there's a significant minority of individuals in those fields of women and vice versa for men.

What do you think was our typical ancestral setup for mating when it comes to the way that we got together, stayed together? I think that, let's come back to the alien, right? So what the alien decides to look at our sexual behavior, I think one thing it would notice immediately is that we're pretty varied in what we do. As long as they're not really with the strict norm saying you absolutely can't do X, Y, or Z. We do a fair amount of X, Y, and Z. I think that the most common reproductive pattern though that we engage in is pair bonding. That's the most common. So we do some pair

bonding that we have polygyny as well. It's not too uncommon across the cultures of the world that some guys will have more than one wife. And there's some casual sex as well, and every culture on record, there's some casual sex as well. Pair bonding though does seem to be the most common setting for sex and reproduction. Even in societies that anthropologists classify as being polygynous. To say that a society is polygynous basically just means that polygyny is acceptable. You're allowed to do it if everyone involved wants to. Actually, that's maybe it's not necessary for everyone wants, wants to do it necessarily.

Sometimes there's coercion. So I'll take that back, but you are allowed to do it. Um, but even in those societies, the majority of actual relationships are pair bonds. So that's our most common one. Yeah. Yeah. How, how do we get to a situation where people assume that, I just free wheeling, sleeping around, you don't have sexual jealousy that is an actual innate

problem, this is just your resistance that needs to be overcome through some combination of psychedelics and meditation. Like how do we get from what seems to me to be quite an obvious setup of it takes like between 10 and 15 years to get an infant to maturity so that it can stand on its own two feet and look after itself. Therefore, you probably need people that stay together for at least a good portion of that, what like what's being missed? What's, what's modern dating sort of modern mating done to that? Like innate understanding.

Yeah. Yeah. Uh, that is a good question. Yeah. I don't know. So I think, so, so people have argued for quite a long time that things like jealousy are just a social inventions. I don't know. So I think people have argued for quite a long time that things like jealousy are just social inventions. And I think there's very good evidence that they're not. I do

think though that people differ. I was thinking about this a while ago and I do wonder if there are maybe three kinds of people. There are some people who get jealous and just could, a pair bond suits them really well. And they couldn't possibly contemplate or enjoy an open relationship or a polyamorous relationship. And I think there are some people who are kind of the reverse of that, a small number of people who just naturally are polyamorous and they don't particularly get jealous. And I think there may be some people in between who do get jealous and who do naturally feel that way, but who can, if they decide to, they can kind of hack their brains.

Or perhaps just insanely high social sexuality to the point where it kind of outweighs the potential sexual jealousy, not that they don't feel it, that that's overclocked on their desire for sexual variety, et cetera. Yeah. Yeah. Yeah. Yeah. I that that's overclocked on their desire for sexual variety, et cetera. Yeah. Yeah. Yeah.

Yeah. I think that's likely. Um, yeah. So I think that, so some people can hack, hack it, hack the system, so to speak. I think, I think if they think that jealousy was just implanted by culture and culture alone, they're mistaken about that, but that doesn't mean that some of those tricks to get rid of it might, they might work for something. I think it's like a belief in belief in determinism, not believing in it means that you don't need to believe in it.

Okay. So how likely do you think it was that humans would have stayed together for life? And how likely do you think that were monogamous or serial monogamists? I think that both happened, but serial monogamy was more common. So I've seen data for instance in hunter-gatherer societies that most first marriages don't last for life. So most people will split up and have subsequent marriages as well, but that a small number do. So I think maybe that a small number do. So I think maybe among, I think it was the kung san. Maybe I shouldn't say actually because it was the kung san or the hadsa or something like that. I saw data on it and I think around 5% of marriages just lasted for life. So the majority don't. And I think in our own culture, we see this, right? Is that most people fall in love more than once in the course of their lifetimes.

You do get both, but just serial monogamy is more common. I suppose the rarity, ancestrally would have been a viable fertile couple staying together for a little while and not having children though. You know, we've decoupled having sex from producing babies now. Yep. Yep. Yep. And sometimes that's to the detriment of like, there's a theory you've probably heard of that, um, that there's a sort of built in tendency that you partner up

with somebody and if there are no, if no kids come along, that you just de-partner that there's a built in tendency to sort of move away from. I got absolutely annihilated for dropping this theory about two years ago and we repurposed it into a, I mean, it's just, it's very difficult. Like it's uncomfortable for people to hear, Hey, if you and your partner have been in a relationship, you get together at 21, you're like, when we get to 30, we're going to start having our family, but we're going to enjoy our twenties first. And over time, due to no, neither of your two faults, maybe you're on birth control,

maybe you're just timing it right. I don't know. Maybe, you know, cycle tracking, whatever. But ancestrally, the only reason that you and another partner would have been together for a long amount of time and not had children would have been that there was a problem with someone. Is it you? Is it them? You don't know. But what you certainly know is there is a 50% chance that if you

stop being in love with them and go off with somebody else, that maybe you're going to be sweet. And I said that and it got re-clipped. And it's a, an uncomfortable thesis for people to hear, especially people who are maybe in relationships that are eight years long and have been intending on holding off having children for a little while. Uh, so, yeah, but I love it. I love it as a theory.

Yeah, it works. And one of the reasons I take it seriously is that there is pretty good evidence. I think that you find the same thing and pair bonding birds that if birds pair up and if they, one or other is infertile. And actually there's a third option, which is that the couple together can be, they just, yeah, yeah, exactly. And they could both have kids with somebody else, but for some reason, there's a third option, which is that the couple together can be, they just, yeah, yeah, exactly. And they could both have kids with somebody else, but for some reason, it's just not the right match, but in birds here, the same thing that they don't,

um, there is no offspring little chicks coming along, uh, you know, in the, in the breeding season, they will, they will split and try again. What do you make of the fact that if what you've said is correct, uh, maybe 95% ish of unions ancestrally would have not lasted for life. What should we make of the fact that we have a culture and a relationship setup system ingrained that looks down on and disparages unions that do end up in a way that may be more sort of ancestrally aligned. Um, in the sense of not lasting for life, right?

Yeah. Um, that is an example of where culture is kind of pushing against our nature to some degree. And I think that, I don't know, but especially in the past, right, there was massive stigmatization of divorce, couples who are divorced. That was just sort of like a really, really big deal. And I would have made it a lot harder for them. And I think it probably made it a lot harder for the kids as well. It's hard enough for kids when the parents split in general.

But if your culture is strongly stigmatizing it and therefore it's very, very rare, then that's just going to make it twice as hard for the kids. And I think it was probably the cause of quite a lot of needless misery where people who were miserable couldn't split up if they were forced, especially in the past, forced to stay together. I think it caused a lot of needless misery and, um, you know, splitting up too easily, especially if you have kids, that's a, that can be a problem as well. But I think there's got to be a, there's got to be a balance somewhere, a middle ground somewhere in between those extremes. You know, how many divorces were registered in the year that Charles Darwin was born?

How many divorces? No, I'm not sure. Four. Is that right? Four. That's fascinating. Nationally. Yeah, well.

That's not four per thousand. That's not four per county. Four. Four in total. All the UK. Four in total. Correct. Yes. Four in total. Yeah. So funny. It's just, that's another, uh, Robert Wright ism from, uh, interesting.

Yeah. This is from the moral animal. Yeah. The moral animal. Sorry. Oh, yeah. Okay. Interesting.

Yeah. What can we, what can we tell about our mating preferences from our testicle body size comparison? Um, can you imagine how, how surprising that question would sound? Why is he going to? Someone who had, exactly. It's yeah, it's a bizarre fact, but the relative size of males' testicles is related to the mating system of a species.

And so in our friends, the bonobos who we discussed earlier and chimpanzees as well, basically everybody mates with everybody. And in that context, the best way that males can boost the number of offspring that they're gonna have is to produce more sperm. So on exactly the same principle that the best way to win the lottery is to buy more lottery tickets. If lots and lots of people are mating,

chimps rather are mating with the same female, produce more sperm, you boost your chances of being the one that actually fertilizes the egg and size the offspring. So yeah, so they've evolved huge testes relative to their, their body size. And in fact, their testes are almost as big as their brains. I've seen, I've seen a photo of a chimp, a chimp brain and chimp testes. And the testes are only a little bit smaller. You say that you're being led around by your penis or by your genitals, not by your brain, it actually goes through. Totally.

Uh, and that's, and chimps are quite smart too. So they're pretty big brains. So. Terrifying testicles. Absolutely terrifying. Uh, at the other end of the spectrum among the primates, we have gorillas, for instance, so gorillas, uh, massive, massive creatures, did massive males. They have a harem of females.

And although the males mate with all of the females, each of the females, while they're in that particular harem, each of the females only mates with one male, which is the harem master, the big guy. And therefore, you don't have sperm. It's called sperm competition when you have lots of sperm from multiple males in the females reproductive tract at the same time. But you don't have that and gorillas because the males, the only ones that make with the females. Um, and so they have very, very small testes. So they're massive, muscular, huge, scary, uh, creatures with tiny, only tiny testicles.

Don't tell him he's like, he'll come and get you all the way in Singapore. He'll come and get you all the way in Singapore. He'll come and get you. And then, and then the question that everyone wants to, and I'm sure everyone's thought of this already. Okay. So where do, where do humans fit within the scale from bonobos and chimps at one end to gorillas at the other? And the answer is that we're somewhere in between.

So we're close to the gorillas, but we are, we're somewhere in between. So we're close to the gorillas, but we are, we're somewhere in between. And a lot of people have interpreted that to mean that we have walked some way down the path toward chimpanzee level promiscuity. We haven't gone anywhere near as far as then, but we have walked somewhere down the path to that. And I don't know if that's necessarily wrong, but there's an added bit of information that you need, I think, to properly interpret that, which is to look at gibbons. So gibbons are another primate, they're a pair-bonding primate, and actually their relative testis size is very, very close to ours. So we're closer to the pair-bonding gibbons than we are to the promiscuous chimps and bonobos. And so the moral of that story, I think,

combined with what we know about human behavior is that there's possibly been some degree of sperm competition in our ancestral past, but not a huge amount. So some degree of promiscuous mating, in other words, but not a huge amount. And again, I think that pair bonding is our most common format. What do you think about the mutual mate choice model? Are you familiar with this? I named it. No way.

Yeah. Yeah. So, um, me and Andrew Thomas did actually. So we worked on a paper. Andrew for the people who don't know Andrew is a horrible, horrible Welshman. Uh, thatman that I love dearly. He's a great guy and is a great researcher and he's produced heaps and heaps of great work.

He was my PhD student and while he was my PhD student, we did this paper called The Ape that thought it was a peacock in which we argue for this idea that humans are sexually dimorphic, but that it's easy to exaggerate the extent to which we are dimorphic. And in that, we coined the terms mutual mate choice model, MMC model, we called it, and MCFC model. So males choose, females compete. Other way around. Males compete, females choose. males choose, females compete. Other way around, males compete, females choose. And the idea is, these are two different ways that you can construe human sexual behavior. One way is the MCFC model. So males compete with each other for access to females and females choose from among the competing males. And males do all of the competing, females do all of the choosing.

The mutual mate choice model, on the other hand, the MMC model, that's the idea that both sexes compete for desirable mates and that both sexes are choosy to some degree about their mates. And we argue that we fit more with the MMC than the MCFC model. You do still have the same sex differences, but they're in a muted form. So although both sexes are choosy in our species, rather than only the females being choosy, at least both sexes are choosy at least about long-term mates. But females are choosier.

So you do have the same sex difference, but it's muted. And likewise, with competitiveness for mates and intersexual competition, intersexual competition in both sexes, but it's ramped up in males compared to females, especially when it comes to risky competitive tactics and aggression and the like. That much, much stronger males than females, but both sexes do it rather than just males competing and females just not competing at all. Why? Why is this the setup that you think that humans have? Because of our big brains is the short answer. So basically as we evolved our big brains and our high intelligence and our cultural capacity,

that all the culture that we had that was so confused the alien, as that happened, it became more and more intensive to look after kids. So for most apes, the females can do it alone. The females can look after the kids all by themselves and they don't need help from anybody else. And that's not the case with our species

for a number of reasons. So one of them is that when babies are born, they're completely dependent. They can't even grip onto anything like the young of most primate species. And that's because we're in effect born prematurely because it's the only way to get a big brained baby out of the reproductive tract is to be born in effect prematurely. And basically if we appeared on the scene,

if babies appeared on the scene in the same developmental stage as most primates, pregnancy would last about, I think it's close to two years, maybe a horrifying prospect. Yeah. And then, and then rip a person in half when it's, uh, exactly. Exactly. Yeah. And as, as I mean, presumably that happened in the process of selecting. Oh, wow.

Of course. Yeah. Which is a really horrible thought. Yeah. Yeah. Which is a really horrible thought. Yeah. How many proto human females died during childbirth because their genetic mutation was like, ah, we'll test it 12 months.

Who cares? Yeah. Oh, for the sake of our intelligence and cultural capacity. Um, so that's the first thing. So they're completely dependent at birth and then, um, just takes a lot longer to get a human being to be nutritionally independent. Is that the, is that the, the, uh, barometer nutritionally independent? Yep.

Yep. So, um, not, not being in the red in terms of, of nutrition, not, not being, uh, you know, making at least as much as you're receiving, uh, and that can take up to 18 to 20 years, even, even in a traditional non-state society. So for both of those reasons, women can't do it alone. So I think as our big brains were evolving, they must have coevolved with various forms of what's called alloy maternal care. So in other words, care from individuals other than the mother. And that can come from different sources. It often comes from the woman's mother, so maternal grandmother of the kid, siblings, especially sisters of the mother, various other sources,

maternal uncles, et cetera. Very often though, it comes from the father. So often fathers are the key investors, which makes a lot of sense, right? Because the father's the only other adult in the world who's as closely related to that kid as the mother is. So it makes sense that in many cultures, and we do find that in most cultures, maybe all cultures that men invest a lot more than most male mammals.

So evolution of male parental care. And then the key thing is that as we started forming these pair bonds, as we started having male investment as well as female investment, that reduced the sex difference and reproductive variance that we were talking about earlier. So the maximum offspring number for humans, other than a few exceptions, who would have had heaps, but in general, it would have come down quite a bit. And as it came down, that would select for a lower level of dimorphism in our species than is typical of mammals.

One other paper I didn't realize, cause I went on your Google scholar and had a big, deep dark rummage around. You've done a good bit of stuff about men insulting intimate partners. Why or when do men do that with the significant other? That is going way back into the past. And that's, that's not research that I led. So I shouldn't say too much about that other than, other than the gist. Um, but the gist of the idea was that men sometimes use derogation of their partner basically as a

tool for, believe it or not, for keeping their partner. So David Buss talks about this quite a bit, right? He talks about the ways in which men keep a partner. And they fall into two main categories, the carrot and the stick. So the carrots are nice stuff, so people are more attentive, they give gifts, they're kind, all the good stuff. Sometimes though men will forget about the carrot and go with the stick instead and use various ways, unpleasant ways to try to keep a partner under the thumb. And the rationale for all that research was that one of those ways is kind of insulting them. So if you could persuade somebody that they're not so great, then they're less likely to think, well, maybe I could do better than this guy. That's the main rationale. And it's not a recommendation, by the way. I'm always nervous talking about this stuff.

Yeah, it's not a prescription. No,. I'm always nervous talking about this stuff. No, we have a unreasonably reasonable audience. So, and moving from a benefit affording to cost inflicting, mating strategies. Everyone's seen that and everyone's seen it on the reverse side as well. You know, they've seen it with, with women too, the, this fear that maybe your partner is slipping away from you. So when he says that he wants to go and hang out with the boys, it triggers a little bit of jealousy or uncertainty. Is he actually spending time with the boys?

So then you make him feel guilty for spending time with the boys, which means that if he doesn't spend time with the boys, I mean, one of the worst ones that Bus talks about is that, like, I can't remember the term for it, the isolation from male kin and support. Yeah. I can't remember the name, but I know what you mean.

Yeah. Where basically if a woman has fewer males that are not brothers, uncles, father, et cetera, around, then it's going to be harder for her to leave. You know, like resource independence is basically going to be tougher for her to get to. So yeah, it's wild man. I mean, when I think, when I think about just how many of the.

Impetuses and impulses we have as humans that we assume are either of our own making or at the very least under our control. I I'm a huge fan of agency. I love the idea of being the author of my own desires and direction in this world. And, you know, it's the Jonathan Haidt thing of the rider atop an elephant, but it's not the elephant that's got the blinkers on. It's the rider. And how have you learned or how would you describe or advise the audience of how to fold evolutionary psychology thinking

into their view of what it means to live a good life, of how to feel like the architect of what they're doing? Because I think people can learn about how their desires and defaults are highly preset and highly disposed in a variety of directions. And it can feel disempowering. It can, I once tweeted Jeffrey Miller asking how to deal with like the discomfort of learning stuff from evolutionary psychology.

So have you got any advice of how you've done that? Yep, well, I've done that? Yep. Well, I do agree that it can feel disempowering. I agree, but I think actually that, um, longer term that it can be empowering, um, for a few reasons. So one is if you have a good understanding of where these impulses come from, um, they can stop seeing, they can stop seeming like, like your emotional reactions and your desires and that kind of thing can stop seeing direct perceptions of the nature of things. It really objectively is very, very important for me to do this. And this is really good and this is really bad. It can allow us to take a step back from that and potentially

deflate those feelings to know where they come from and to know that a lot of the feelings that we have in our minds because they, on average, let our ancestors to pass on their genes in ancestral environments. And so we can think, well, my goal isn't to pass on my genes. I've got these other things that I think are more important. Therefore, I'm not going to take these emotional reactions as seriously as I would otherwise. And I do think it works. I do think it can deflate our feelings. One example that I think it was one of Steven Pinker's books. He was talking about how people are feeling high status kind of people who strut around and that kind of thing, when you see that chickens do the same thing and the males puff up, it doesn't make you

think, oh, cool, this is even more important than I thought. It deflates it. It makes you think, oh, this is just a silly animalistic tendency. So I think that's one way I think that it can help. It can deflate things so you can more easily choose, look, what do I really want to do rather than just going with your gut instincts. Then the second thing I think relates to what we were talking earlier about jealousy and whether people can hack their brains to get rid of their jealousy.

And I do think a lot of people can't do that. But I think that if people think that they can, they might think, okay, this jealousy, I do feel this jealousy. I've got this partner who wants to have a polyamorous relationship. I don't like the idea, but that's just because of society. I can cast it off just as easily as it was taught to me. And if they know that, quite possibly, that's not the case, that there is an evolutionary origin to that emotion and that therefore quite possibly they're not going to be able to cast it off, they can make a more informed decision. I think they can think, well, I'm probably not going to

cast it off. This probably is going to be unpleasant for me whether I want it to be or not. So I just think that this is perhaps not the relationship for me. And they can steer clear of it because they might realize that it's unrealistic, that they can just reprogram reprogram themselves so easily. Not to say there's anything wrong, like polyamory does work for some people. Um, but having those kinds of thinking tools can, can help you think through whether it's going to actually work for you or not. Certainly for me, letting go of castigating myself for thinking a thing

or feeling a thing, very difficult, right? Because we want to hold two competing thoughts in our mind at the same time. One being, I am in control of my outcomes. The other being, I did not get to design my source code. And like these two things are just going to continue to clash up against each other. And, you know, David Hawkins wrote a great book, letting go. And that happens to be the thing that you try to do with emotions when they arise in meditation. It's the thing that you are trying to do with this also. Look, I can, I can try and leave it all on the field of play and control my

destiny and at the same time know that I don't have full control. I don't really even have partial control. Yep. Yep. And that kind of thing, letting go and meditation, that's those other ways that we can hack our brains. There are ways, there's a definite evolutionary push in certain directions from our genes, but our genes aren't the only things that are shaping us.

And therefore, we can sometimes push back at least to some degree, which is nice. And I know one reason that people resist evolutionary psychology is that they dislike that. They dislike the idea that they're just puppets of their genes. And I do think though that, well, first of all, an evolutionary perspective doesn't say it's just genes, right? So it would say that your puppets are the genes and the environment, really. But that would be my other thought is that if being a puppet is the problem, rejecting an evolutionary perspective isn't a solution, right? It's just choosing an alternative puppeteer because the environment, if it's just the

environment, well then it's just the environment that's shaping our source code instead. Which is even more ruthless. I mean, you recently did a great post about behavioral genetics, Plowman's been on the show and if you were to get to a world where, uh, all genetic differences between people had been flattened out or gotten rid of or accounted for the entirety of the difference in your outcomes in life would be laid at the feet of your environment. And that seems like even more fucking brutal.

Exactly. Exactly. Pick, pick what it is that you want. Like your poison, right? Yeah, exactly. Um, so, and yeah, sorry, go ahead. Just, I'm kind of thinking about whether or not we are fated to fail at discovering a greater reason for our existence.

If all that we are are just propagators for our genes, like, is it all just futile? This trying to, trying to get something more out or is there a realistic path to enlightenment here? Nice, easy question. I mean, what sort of, what sort of higher things are you thinking of? Meaning beyond the immediate, like trying to find a way to contribute to things. It seems especially upon your book and most evolutionary psychology, I think speaks to you in the mood or the vibe that you're in at the time. Like if you read something about reciprocal altruism, when you're feeling full of serotonin

and everything's going well, you think, God, how great that I love my mom. And how fantastic that I rang her last week. But if you read it when you're feeling a little bit more zero sum and like the world's out to get you, you just see it as a thinly veiled mask for selfishness, masquerading as selflessness. And I'm trying to work out whether or not, how we can take more pleasure in the things that we can take more pleasure in the things that we want to take pleasure in beyond this is just a transaction for

my genes to get themselves toward the next generation. Interesting. Um, so I wrote a bit about this in my first book, um, which was called the Allen guide and the meaning of life. And in the meaning of life section of that book, I looked at the question of, is there, is there any ultimate meaning to life? Is there any meaning to life in any sense? And I concluded with a message that initially might seem a bit of a downer, which is that there's no ultimate meaning to life. So no meaning to life imposed on us from outside of ourselves, from a God or any kind of meaning

imprinted into the basic nature of existence. But I don't think that is necessarily terminally a downer. I think that once you get used to that idea, in a way, it gives us a kind of freedom. And the freedom is that we can choose our own meanings in life rather than having a meaning imposed on us from outside of ourselves. So we can choose a meaning. And our genes may be to push us into a direction that we can quite easily feel cynical about. It's just in the interest of the genes. And yeah, some of the stuff is kind of nice, but ultimately it's just about gene propagation. But having turned us into a cultural animal and an intelligent animal, it made us an open system. I think we can think beyond that. And that's what we're doing when we learn about evolutionary psychology and step back from looking at our evolved nature and thinking, okay, well, what

do I actually want my life to be about? What do I think is more valuable? If I don't think transactional than the other thing, what are bigger goals that I do think are important that I can choose for myself? And for some people that might be like effective altruism and dealing with existential risks. And for other people, it might be something, you know, something more modest.

But I do think that the fact that we are evolved creatures doesn't preclude, doesn't preclude being able to go beyond our evolved nature via culture and to do other things that, and choose other values beyond what's been bequeathed to us by natural selection. You know, you do get to be the architect in that way. I think again, it, as it comes down to with many things, it's holding conflicting ideas or at least slightly sort of tensionary ideas in your mind at the same time.

Before we finish up, I learned something John Tooby passed away last year. I was very fortunate that I got to meet him. Yeah, great guy, right? Phenomenal. I think David Bussay is one of only two people he's ever met in his entire life who justifies the title of genius. I agree, and also a really nice guy. Phenomenal dude.

Also, most importantly, subscriber of Modern Wisdom. So that was the best thing. Someone sent me a article looking at a quote of his and deconstructing it and we're an hour and 20 minutes into the episode, so anyone that's not reasonable is already left. So I wanted to have a quick chat with you about it. It's the crumbling genome theory of population dysgenics. Crumbling genome theory of population dysgenics, right?

So basically, Tooby's argument is that each time that a new generation comes along, there's some genetic mutations that get filled with every time that that happens, some of them are better. And some of them are worse. Some of them are more optimal and some of them are more suboptimal. When selection pressures in an environment get released through things like healthcare environment get released through things like healthcare and the ability to improve medicine and a germ theory of disease and so on and so forth, you relieve some of the selection pressure.

You know, somebody that was blind in both eyes probably didn't last very long, ancestrally. Somebody who was born without legs probably didn't last very long, ancestrally. In the modern world, we have technology that can thankfully keep those people alive. The problem being that you are accumulating mutational load that ancestrally would have been suboptimal, making no judgments about the people that are alive today, but that his, the balance, the genome balance needs to be you discarding suboptimal mutations at the same rate as you acquire optimal mutations. And if you roll this forward

over a long enough time that basically a reduction in selection pressure results in an increase accumulation of all of this stuff. Now here was the really spicy bit that someone put, if that wasn't spicy enough, right, the really, really spicy bit that someone put toward the end of this article was perhaps this explains birth death, which is if you as a human who has a genetic mutation, even like just normal persons walking around all over the place, uh, if you make it to reproductive age and you're for some reason, there's just something about you that shouldn't go on to the next generation, who's to say that your desire for children wouldn't just be nerfed a little bit, or

maybe your desire for sex wouldn't just be tuned down a little bit, perhaps enough so that you don't end up making children and taking them forward. So when you think about, you know, the ever increasing rates of depression, anxiety, like antisocial behavior, all of that's the maladies that people are dealing with mentally at the moment and the ones that people are dealing with physically like obesity, et cetera. How many of those would have been selected out ancestrally and how much is the decline in desire for children and subsequent birth rate collapse, a population wide prophylactic or a filtration net,

stopping those particular individuals from going to the next, next generation. Interesting. So a lot there, spicy, like you say. And so I guess the first thing is that that's all, that's all perfectly possible. Right. So I do think that, so one example, right, is that in ancestral times, myopia was probably a much bigger problem for survival than it is today. And people who had genes that predisposed them to myopia and couldn't really see so well, probably were less likely to put forth their genes. That's been released for quite

a long time. We have glasses and things now. we have cultural ways of meaning that there's just no longer a problem. And I think it's quite plausible that the average genetic quality of eyesight could have deteriorated to some degree for that reason. And that would just be one example. There could be others along those lines. And then it's tricky to know how do you deal with that? Right. So you couldn't say, okay, well, we're just going to ban glasses. So that this doesn't happen anymore. People that have got myopia die at a higher rate.

Exactly. So they just wander randomly into traffic and take, take their myopic genes out of the gene pool. Uh, so we couldn't do that. I think, um, what could happen is that. The more that these kinds of technologies evolve culturally, the more dependent that we will, dependent will become on them, not just habitually, but also biologically as well.

I think it's possible, you know, people are looking at ways of, so to speak, mending the genomes for like major health. So genes that contribute to major health problems, it's not implausible that the time will come when it's possible to filter those out or to, if you have offspring, you can choose to go with, I don't know, fertilized eggs and choose the ones that don't have genes.

Embryo selection for positive traits. Yeah, that's the phrase. Yep, exactly. Yeah, I think that, well, actually, I think it's embryo selection for. Yeah, that's the phrase. Yep. Exactly. Yeah. I think that, um, well, actually I think it's embryo selection against negative traits. I think is the main one that people are. Yeah. Yeah. Um, and now the prophylactic idea I'm not so sure about, cause that sort of seems like a, like a good of the group explanation. So like it would be good for the species as a whole, if we would have that kind of doled down sexual desire or desire for kids. But what would that be in?

What would be in it for the individuals with those designs? Why not just roll, why not just roll the dice anyway? What do you care about resource depletion? Like there's no tragedy of the commons baked into our genes. Yeah, yeah, yeah. Exactly. Exactly. I do know though, that with, with things like that, well, actually most mental

illnesses, so depression, schizophrenia, the vast majority of mental illnesses are actually associated with lower number of offspring. So there's certainly, I think there is some filtration going on in some areas. Yeah, that's a really good, that's a really good point. The fact that you don't have this God's eye view, population wide coordination thing, what like, give me the mechanism through which your genes would just be like, just have a crack, like see what we don't know what's going to happen. Maybe, maybe you were a blip and they're going to be, they, they can

fly like the net your kids can fly like, who knows? Um, that's really, really interesting. Maybe you were a blip and they're going to be, they can fly like your kids can fly. Like who knows? That's really, really interesting. Steve, I'm a huge fan of your work. I'm a huge fan of your Substack. Your book's fantastic. I'm excited for whatever the next thing is. Where should people go?

They want to keep up to date with everything that you do. Well, my Substack is my favorite thing at the moment. I really love Substack is my favorite thing at the moment. I really love Substack. It's taken over from Twitter in terms of my favorite social media outlet. So that's called the Nature Nurture Nietzsche newsletter and it's stevestuartwilliams.com. I am still on Twitter as- Sorry, go ahead. Nothing. Just I wanted to know where Nietzsche came in. I haven't seen you write about Nietzsche yet. Yeah.

I'm not sure what's the greatest name for us for the sub-stack because I love the clever play on words and I love philosophy and that's what it is. So I love nature, nurture issues, and I love philosophy and it's kind of, Nietzsche stands in for philosophy as a whole. I do quite like Nietzsche's writing style. I'm not a huge, I'm not actually a huge fan of Nietzsche. Maybe it's not the perfect title. People probably think I'm a Nietzsche nut, but I'm a philosophy nut instead.

And I'm on Twitter as well. It's at Steve Stuwell. So S-T-E-V-E S-T-U-W-I-L-L. Oh yeah. Steve, I mean L. Oh yeah. Steve, I mean, you're, you're fantastic. I, uh, I can't wait to see what you do next. Well, awesome.

Thank you very much, man. It's been, there's been a lot of fun. I've really enjoyed this conversation.