The Uncomfortable Science Of Sex Differences - Steve Stewart-Williams

1. 0:00 – 2:07

   Why Sex Differences Are So Controversial

   1. CWChris Williamson0:00

      Do you think that you could have published this book six years ago?

   2. SSSteve Stewart-Williams0:03

      I think that I could have, but it would have been a less wise move. [chuckles] I think it would have gone down, uh, a, a lot worse six years ago. Things have kind of cooled off a little bit, I think.

   3. CWChris Williamson0:13

      Why is talking about sex differences so controversial?

   4. SSSteve Stewart-Williams0:16

      Well, it's a good question, and I think that it's a few things. I mean, sometimes it surprises me because sometimes I think a lot of the differences that we're talking about, they're really quite modest differences. Um, they are often differences in preferences rather than cognitive abilities, so they're kind of neutral as far as I'm concerned. Um, and if anything, I think probably they put men in a worse light than women. Um, so sometimes it surprises me, but I think really the main reason is our long history of sexism against women, and I think that we've got quite a long... Science as well has a bit of a sordid history in terms of how we've spoken about women, especially in the 1800s.

   5. CWChris Williamson0:54

      Mm.

   6. SSSteve Stewart-Williams0:54

      I've, I've got a quote, one of my favorite quotes, one of my favorite examples of this is from, um, a scientist by the name of Gustave Le Bon, and he, he wrote that, uh, "Sure, there are some women who are as intellectually accomplished as your typical man, but they're about as rare as a, as a two-headed gorilla, and so therefore we don't really need to think about them, think about them." Um, so with stuff like that in our background, it's, uh, I guess not surprising that people are a little bit w- a little bit nervous about talking about evolved sex differences, a little bit worried that if we start doing that, it's going to open the door to that kind of, that kind of sexism. Um, I think they're wrong to worry about that.

   7. CWChris Williamson1:30

      Mm.

   8. SSSteve Stewart-Williams1:30

      I think that really the science of sex differences has disproved those kind of ideas. Um, and I think, I think as well that we can treat men and women respectfully and, uh, and as humanely and treat them well, uh, even if men and women are not identical on average on every single trait.

   9. CWChris Williamson1:50

      Yeah, I suppose the history of science is to sex differences what the Nazi Party is to behavioral genetics.

   10. SSSteve Stewart-Williams1:57

       Right. Right. Exactly. Yeah. Yeah, and I do think that, um, science is the solution to the early sexism rather than a continuation of it.

   11. CWChris Williamson2:05

       Yeah, that's a great way to put it.

2. 2:07 – 7:55

   Why Sex Differences Matter

   1. CWChris Williamson2:07

      All right, w- why is it important to study sex differences then? Why, why should anybody care?

   2. SSSteve Stewart-Williams2:11

      Uh, I think lots of reasons. The main reason for me is I think it's just deeply, deeply fascinating. I just think it's- [laughs]

   3. CWChris Williamson2:17

      It's the best.

   4. SSSteve Stewart-Williams2:18

      Yeah.

   5. CWChris Williamson2:18

      It's the m- it's the best. Me and you fell in love with the same book, The Moral Animal by Robert Wright.

   6. SSSteve Stewart-Williams2:22

      The Moral Animal.

   7. CWChris Williamson2:22

      It ch- it changed my life.

   8. SSSteve Stewart-Williams2:23

      Yeah, likewise.

   9. CWChris Williamson2:24

      Yeah.

   10. SSSteve Stewart-Williams2:24

       It changed my life. It, um, shaped the rest of my career. Um, just I think it's deeply fascinating and, um, yeah, I remember when I read that book, uh, that's when I fell in love with, uh, fell, fell in love with evolutionary psychology and in particular fell in love with the evolutionary psychology of, of sex differences.

   11. CWChris Williamson2:42

       Mm-hmm.

   12. SSSteve Stewart-Williams2:42

       And I got the same feeling that I did when I was a, a kid and I first understood how the phases of the moon work and everything just clicked into place. Suddenly the whole thing made sense.

   13. CWChris Williamson2:50

       Oh, that is why it looks that way.

   14. SSSteve Stewart-Williams2:53

       Exactly.

   15. CWChris Williamson2:53

       That is why people are different in that way.

   16. SSSteve Stewart-Williams2:56

       Exactly. Exactly. It all made sense. It was clear that it was true and, uh, yeah, just, uh, sort of instant insight and, uh, yeah.

   17. CWChris Williamson3:04

       Interesting. Even as you're saying it, I can hear this sort of critic preparedness inside of my mind going, "Why would you when you read a book, why would both of us when we read a book be so enamored by sex differences... That must be because you are secretly a sexist who is looking to try and keep people in their place and not ever have any progress..." Da, da, da. You know what I mean? Like the-

   18. SSSteve Stewart-Williams3:28

       Yeah

   19. CWChris Williamson3:28

       ... the conversation around this has become so, uh, tarnished, um, that it's-

   20. SSSteve Stewart-Williams3:33

       And accusatory.

   21. CWChris Williamson3:34

       Yes. Yes.

   22. SSSteve Stewart-Williams3:35

       Yeah.

   23. CWChris Williamson3:35

       Yeah. That-

   24. SSSteve Stewart-Williams3:36

       Yeah

   25. CWChris Williamson3:36

       ... you, you can't have an interest in something which is fundamental and fascinating and really important-

   26. SSSteve Stewart-Williams3:41

       Yeah

   27. CWChris Williamson3:41

       ... right? So that you don't try and... people aren't trying to fight against something so that we don't fully account for and understand why behavior unfolds in particular ways that can allow us to have a better society, a society that's got outcomes that's more close to what we want.

   28. SSSteve Stewart-Williams3:56

       Yeah.

   29. CWChris Williamson3:57

       Fascinating.

   30. SSSteve Stewart-Williams3:58

       Yeah. It is. Um, yeah. So I do, I agree with that and I think, uh, yeah... Sorry, I just, uh, I just went blank. What was, what was I going to say about that?
3. 7:55 – 13:21

   What Actually is Sex?

   1. SSSteve Stewart-Williams7:55

      They actually do indeed

   2. CWChris Williamson7:55

      All right. There's been a ... The last few years, there's been a huge debate about what sex actually is.

   3. SSSteve Stewart-Williams7:59

      Yeah.

   4. CWChris Williamson8:00

      What's the definition that you land on?

   5. SSSteve Stewart-Williams8:03

      Uh, well, there are a few definitions. The one that I land on is the traditional scientific definition, uh, via which sex is de- defined in terms of gamete size. So in the vast majority of sexually reproducing species, uh, you have two different gamete sizes, and the small gametes are called sperm, the larger gametes are called eggs.

   6. CWChris Williamson8:23

      Is that across the board?

   7. SSSteve Stewart-Williams8:24

      That is across the board, yeah.

   8. CWChris Williamson8:25

      No way.

   9. SSSteve Stewart-Williams8:26

      Yeah.

   10. CWChris Williamson8:26

       Okay. So every, every, or almost every sexually reproducing male-

   11. SSSteve Stewart-Williams8:33

       Yes, produces sperm-

   12. CWChris Williamson8:34

       Yes

   13. SSSteve Stewart-Williams8:34

       ... and sexually reproducing female produces eggs.

   14. CWChris Williamson8:36

       Right

   15. SSSteve Stewart-Williams8:37

       And-

   16. CWChris Williamson8:37

       I know this might, this might be like the most face palm thing. I'm like, wow, I didn't know that that was, those are the only two currencies at play.

   17. SSSteve Stewart-Williams8:43

       Um, I mean, it seems like, so, so in biology, it's not like math, right? So in biology, there are very rarely, uh, generalizations that apply to every single species.

   18. CWChris Williamson8:51

       Mm-hmm.

   19. SSSteve Stewart-Williams8:52

       Um, this is one of them, but the reason is that it's a definitional, it's a definitional truth. So we define males as the ones that produce the smaller gametes.

   20. CWChris Williamson8:59

       Yeah.

   21. SSSteve Stewart-Williams8:59

       Um, the empirical truth that in principle could have gone another way is the fact that in the vast majority of species, you have w- where, where the gametes are not identical, you only have two different types, and one is bigger and one is smaller. And that's true right across, uh, you know, all, all species except the minority where you, uh, you have ... So that's called anisogamy, where you have two different sizes, and you have a few isogamous sexually reproducing species, but the vast majority anisogamous.

   22. CWChris Williamson9:28

       Can you ... What, what's an isogamous sexually reproducing spe- What are some examples of them?

   23. SSSteve Stewart-Williams9:34

       Uh, there are some very, uh, I think no animals and no plants, but I think maybe some simple bacteria and things like that. And I think that wou- that would have been the starting position. So we all evolved from species that originally were isogamous.

   24. CWChris Williamson9:47

       Mm-hmm.

   25. SSSteve Stewart-Williams9:48

       The s- the first of all sexual reproduction would have evolved, then isoga- and they would have been isogamous. They would have produced the same gametes-

   26. CWChris Williamson9:54

       Mm

   27. SSSteve Stewart-Williams9:54

       ... and mixed them. But then that's evolutionarily unstable, and that tends to, um, fall apart into, uh, smaller and larger gametes.

   28. CWChris Williamson10:02

       Why, why is it unstable?

   29. SSSteve Stewart-Williams10:04

       Uh, because when you, when you have same size gametes, uh, the selection for any trait that will increase the chances of being one of the gamete, are, are producing gametes that are going to, uh, produce offspring that survive.

   30. CWChris Williamson10:16

       Mm-hmm.
4. 13:21 – 19:50

   Biology vs Society: What Shapes Sex Differences?

   1. SSSteve Stewart-Williams13:21

      [laughs]

   2. CWChris Williamson13:21

      So much of the sort of debate falls around nature versus nurture.

   3. SSSteve Stewart-Williams13:24

      Yeah.

   4. CWChris Williamson13:25

      So much of it. How do you even begin to start to separate this out, right? No, almost no women have grown up in a society that hasn't had other women with the expectations of women, and almost no men have grown up in society that doesn't have the expectations of men. How do we know that all of the sex differences aren't just socialization?

   5. SSSteve Stewart-Williams13:46

      It's a good question, and, um, I think the first thing I'd want to say about that is that evolutionary psychologists don't deny that socialization has a very important, uh, impact on the nature of sex differences in any given culture. We know that it does have a big impact because we know that sex differences, their size, and the exact details of them, many of them, vary across cultures and vary across times. Um, but in terms of how we know that it's not just socialization, there are various lines of evidence that point in that direction. None of them are perfect. None of them by themselves seal the deal. But the reason I'm persuaded is that they all point in... Uh, when, when you get a sex difference and they all point in the same direction, um, that just makes a very strong case, I think, that is, that is not just due to socialization. And in the book, I, I lay out six different lines of evidence, uh, for an innate contribution to any given, uh, difference. Um, see if I can remember them, eh. So the first one is, um, that a lot of sex differences, they appear very, very early in the lifespan. Uh, so early in fact that even though it's conceivable that it could be a result of socialization, it just seems less plausible than that there's actually also an innate push.

   6. CWChris Williamson14:53

      Hmm.

   7. SSSteve Stewart-Williams14:54

      So, uh, the aggression sex difference and the risk-taking sex difference, both of those appear basically as soon as kids are mature enough that they can move around the place and are capable of risk-taking, capable of aggressing. Uh, you get that sex difference, um, like immediately.

   8. CWChris Williamson15:09

      Yeah.

   9. SSSteve Stewart-Williams15:09

      And, and a good example of that is that, uh, right from the get-go, right from early toddlerhood, more boys than girls end up in the ER from doing more risk-taking.

   10. CWChris Williamson15:19

       Hmm.

   11. SSSteve Stewart-Williams15:20

       Uh, and, and also if it appears at p- puberty as well, um, like a lot of sex differences, uh, innate, uh, sex differences with an innate basis, they-

   12. CWChris Williamson15:28

       What do you mean when you say innate?

   13. SSSteve Stewart-Williams15:30

       Uh, unlearned.

   14. CWChris Williamson15:31

       Right.

   15. SSSteve Stewart-Williams15:32

       Unlearned, yeah.

   16. CWChris Williamson15:32

       Right. Right.

   17. SSSteve Stewart-Williams15:33

       So there's an innate contribution, an unlearned contribution, and where that's the case, often you find that the sex difference, um, you may, you may get it to some degree early in the lifespan, but then post-puberty, it just skyrockets and, and expands.

   18. CWChris Williamson15:45

       Right. Okay.

   19. SSSteve Stewart-Williams15:46

       Yeah.

   20. CWChris Williamson15:46

       Which would suggest that there is a biological basis, or else-

   21. SSSteve Stewart-Williams15:49

       Yeah

   22. CWChris Williamson15:49

       ... why would this big change occur when puberty happens?

   23. SSSteve Stewart-Williams15:53

       Exactly. And, and do so right across cultures. Um-

   24. CWChris Williamson15:55

       Yeah. Is, uh, uh-

   25. SSSteve Stewart-Williams15:56

       Yeah

   26. CWChris Williamson15:56

       ... would the suggestion from social roles, socialization theorists be that while during puberty, culture ramps up its pressure on people?

   27. SSSteve Stewart-Williams16:07

       Yeah.

   28. CWChris Williamson16:07

       There's a greater expectation on young men and women to change their behavior?

   29. SSSteve Stewart-Williams16:13

       That would be the way that you would have to, you'd have to try to explain it, uh, something like that. Yeah.

   30. CWChris Williamson16:17

       Mm-hmm.
5. 19:50 – 21:37

   How Much Do Parents Impact Sex Differences?

   1. CWChris Williamson19:51

      What are the sociocultural explanations that hold water?

   2. SSSteve Stewart-Williams19:55

      Um, well, I think a lot of them do. Um, you know, it's, it's tricky. So I guess we know because of cross-cultural differences in, uh, male typical behavior, female typical behavior, and the size of the differences, that something is making the difference. But it is actually quite tricky to, to figure out what, what it is that's making the difference.

   3. CWChris Williamson20:16

      Mm.

   4. SSSteve Stewart-Williams20:17

      Um, 'cause we know for instance that... Uh, okay, so like a popular explanation is that it's how parents treat their kids, and that seems incredibly plausible that it's gonna have an effect. There are a few reasons to think maybe that it has less effect than we might think. So one is that, uh, a lot of research in the West finds that man- finds that, um, uh, parents don't particularly treat their sons and daughters differently in, in some important ways. Like, they're equally likely to encourage them to be successful, equally likely to, um, encourage them to be independent. Uh, another line of evidence against pr- uh, parents having a big role is what's called the second law of behavioral genetics. Uh, and that's the finding that, um, when two people... Okay, so take identical twins. Two identical twins, they grow up in the same home. You'd expect them to be more similar to each other than two identical twins who are separated at birth and reared apart.

   5. CWChris Williamson21:07

      Mm.

   6. SSSteve Stewart-Williams21:07

      And in childhood, they often are quite a bit more similar than you would expect by chance. Um, by adulthood though, they're often not much more similar at all, and in some cases n- no more similar than they would be, um, if they had grown up apart, which is a surprising finding but a, a very consistent finding. And it suggests maybe that, uh, parental treatment affects individuals less than we might think that they would-

   7. CWChris Williamson21:32

      Mm

   8. SSSteve Stewart-Williams21:32

      ... which kind of pulls out the rug a little bit from the idea that parents are having a huge impact on sex differences specifically.

6. 21:37 – 26:39

   The Gender Equality Paradox

   1. CWChris Williamson21:37

      What about the gender equality paradox?

   2. SSSteve Stewart-Williams21:40

      Uh, well, that, uh, undermines another kind of, uh, sociocultural explanation, which is the idea that, um, the sex differences that we see are products of the social roles of a culture and shaped by, um-

   3. CWChris Williamson21:53

      The social roles theory?

   4. SSSteve Stewart-Williams21:54

      Yeah, social roles theory.

   5. CWChris Williamson21:55

      Right.

   6. SSSteve Stewart-Williams21:55

      Exactly. Um, and, and patriarchy theory, the idea that it's due to patriarchy.

   7. CWChris Williamson21:59

      Right.

   8. SSSteve Stewart-Williams22:00

      Um, uh, that as well is undermined by the gender equality paradox. Um, 'cause both of those theories would predict that in, like, like more patriarchal societies, societies that are more patriarchal, uh, societies that have stricter gender roles-

   9. CWChris Williamson22:15

      Mm

   10. SSSteve Stewart-Williams22:15

       ... you'd expect that and predict that the sex differences would be bigger in those societies, uh, than they are in less patriarchal societies and ones that have less strict social roles.

   11. CWChris Williamson22:25

       What would be some examples of how that would play out if that was true?

   12. SSSteve Stewart-Williams22:29

       Uh, basically any sex difference you care to name. Uh, aggression sex difference, sex differences in masculinity versus femininity, all of those should be bigger. Sex differences in career related preferences-

   13. CWChris Williamson22:40

       Yeah

   14. SSSteve Stewart-Williams22:40

       ... they should be bigger as well. And the gender equality paradox is the deeply counterintuitive finding, and incredibly fascinating finding, that often it goes the other way, seems to go the other way, that actually in more gender equal societies, societies that are less strict in terms of their gender roles, uh, and societies that are less patriarchal, you actually find larger sex differences often rather than smaller ones. Uh, which is bizarre-

   15. CWChris Williamson23:03

       In the direction that you would predict as well?

   16. SSSteve Stewart-Williams23:05

       Uh, yeah, so, so opposite to the direction you predict if social role theory was correct.

   17. CWChris Williamson23:09

       Right. Yes, yes.

   18. SSSteve Stewart-Williams23:10

       Yeah, yeah.

   19. CWChris Williamson23:10

       But in the direction you would predict if you were taking an evolutionary perspective, I would imagine.

   20. SSSteve Stewart-Williams23:14

       Um, well, actually, you know, taking an evolutionary perspective, I, I didn't originally predict that. I, I thought that in more patriarchal societies, e- even given that there's an innate push-

   21. CWChris Williamson23:23

       Yeah

   22. SSSteve Stewart-Williams23:23

       ... towards certain sex differences, I still thought that patriarchy and stricter sex roles would pry the sexes apart even more.

   23. CWChris Williamson23:29

       Right.

   24. SSSteve Stewart-Williams23:30

       So I was actually very surprised-

   25. CWChris Williamson23:31

       But it doesn't

   26. SSSteve Stewart-Williams23:31

       ... it, that it doesn't. And-

   27. CWChris Williamson23:33

       What-

   28. SSSteve Stewart-Williams23:33

       And that it does the reverse is the real surprise

   29. CWChris Williamson23:35

       ... what are the rebuttals to socio- uh, that sociocultural explainers have for the gender equality paradox?

   30. SSSteve Stewart-Williams23:43

       Uh, there are a few. One is that, um, people in more patriarchal societies, they tend to... The, the men and women have little to do with each other.
7. 26:39 – 29:02

   The Top Difference Between Men and Women

   1. CWChris Williamson26:39

      What's the largest sex difference between men and women?

   2. SSSteve Stewart-Williams26:43

      Um, well, the largest ones are physical differences, physical sex differences. So, um, the very largest are sex differences in reproductive anatomy, where basically all males have penises, all females have vaginas and so on.

   3. CWChris Williamson26:56

      Mm.

   4. SSSteve Stewart-Williams26:56

      Um, but other physical sex differences, um, are also very, very large. So the sex difference in upper body strength is, is huge and there's very little overlap, close to no overlap, uh, for that one. Um, the sex difference in voice pitch is another very, very large one as well.

   5. CWChris Williamson27:14

      Mm.

   6. SSSteve Stewart-Williams27:14

      That's huge. Uh, which is quite interesting because, uh, the voice pitch sex difference in other apes isn't, is not as big. It's nowhere near as big. And that's even the case for, um, for other species that are much more dimorphic than us in terms of size, like gorillas and, and orangutans.

   7. CWChris Williamson27:30

      Mm.

   8. SSSteve Stewart-Williams27:31

      So that's a bit of a puzzle. I'm not quite sure why that is, why that's the case. Uh, when it comes to psychological sex differences, the vast majority of them are much more modest. Um, but there's one that stands out as being, as being almost as big as some of these physical ones, and I always ask people if they can guess what it is. I think last time I was on your show, actually, I asked you if you could guess, and, and you didn't, but, but no one does. Um-

   9. CWChris Williamson27:54

      I've read the book now.

   10. SSSteve Stewart-Williams27:54

       You've read the book now, so [laughs]

   11. CWChris Williamson27:56

       Yeah, yeah, yeah.

   12. SSSteve Stewart-Williams27:56

       So you got a head start on that, yeah.

   13. CWChris Williamson27:58

       Can you guess, can you, can you guess what it would be, Jared? The, the single biggest psy- psychological sex difference between men and women. Hmm. Is aggression? Um...

   14. SSSteve Stewart-Williams28:07

       It's not aggression. I'll give you a clue, and that's that it is, it's related to reproduction pretty closely. What was that?

   15. CWChris Williamson28:15

       Perversion?

   16. SSSteve Stewart-Williams28:15

       It's... Well, actually, that is a big sex difference, but [laughs]

   17. CWChris Williamson28:18

       Not as, not as big as this one.

   18. SSSteve Stewart-Williams28:19

       Not as big as this one.

   19. CWChris Williamson28:20

       Speak for, speak for yourself, dude. [laughs]

   20. SSSteve Stewart-Williams28:22

       It's the sex difference in which sex each sex is primarily attracted to. So men, most, the vast majority of men are primarily attracted to women. The vast majority of women primarily attracted to men. And when I say it, it's obvious, right? It's just obvious that it's a big sex difference and, um, but, but it's curious. People don't think of it. Even, um, scientists often don't think about it. I've read a bunch of papers that summarize evolved sex differences, and they don't tend to mention that one. They often neglect to mention that, that very, very large one, but also that, uh, one that has quite a clear evolutionary rationale.

   21. CWChris Williamson28:56

       Yeah.

   22. SSSteve Stewart-Williams28:56

       That's, that's very interesting.

   23. CWChris Williamson28:57

       Of course. Because if that wasn't the case, we wouldn't be here.

   24. SSSteve Stewart-Williams28:59

       Exactly.

   25. CWChris Williamson29:00

       Literally. Literally.

   26. SSSteve Stewart-Williams29:01

       We literally wouldn't be

8. 29:02 – 39:44

   What is the Biggest Sex Differences in Sex?

   1. SSSteve Stewart-Williams29:02

      here. Yeah.

   2. CWChris Williamson29:02

      Uh, okay. So what are the biggest sex differences? Let's get down to some brass fucking tacks. What are the biggest sex differences when it comes to sex?

   3. SSSteve Stewart-Williams29:09

      When it comes to sex?

   4. CWChris Williamson29:10

      Yes.

   5. SSSteve Stewart-Williams29:10

      Um, one of the largest ones is the sex difference in interest in casual sex and sexual variety and, uh... So basically socio- socio sexuality, the trait of socio sexuality, no strings attached sex. Um, uh, do I need to mention which direction it is?

   6. CWChris Williamson29:26

      Uh, yeah, yeah.

   7. SSSteve Stewart-Williams29:26

      People might be aware of it, right? [laughs]

   8. CWChris Williamson29:27

      Yeah, yeah. They, they... Someone can intuit it, I guess.

   9. SSSteve Stewart-Williams29:30

      Yeah. So, so men on average, uh, score higher. Uh, however you measure that trait, they score higher than women on that trait. Um, the differences there maybe though are not, not as huge as people sometimes assume. Um, we're looking usually at an effect size of, uh, you know, about Cohen's d equals one. So what, what that means is there's about one standard deviation between the average for men and the average for women. Uh, so, so yeah, between 0.8 and one. Um, and that is pretty big. That, that is big for a human sex difference, but there is still quite a bit of overlap. So there are plenty of, uh, of women who have a higher socio sexuality than plenty of men.

   10. CWChris Williamson30:10

       Yeah.

   11. SSSteve Stewart-Williams30:10

       Uh, I guess an intuitive way to put it, a way to make it intuitive would be to, to say if you imagine plucking two people at random, one man and one woman with effect size of 0.8 point or, or one, probably two thirds to 70, 70% of the time the man will score higher than the woman on that trait. Um, so that is a majority. It's not an overwhelming majority, though. In a significant minority of cases, you'd find that actually the woman-

   12. CWChris Williamson30:35

       Mm-hmm

   13. SSSteve Stewart-Williams30:35

       ... scores higher than the man.

   14. CWChris Williamson30:36

       Mm-hmm.

   15. SSSteve Stewart-Williams30:37

       Yeah.

   16. CWChris Williamson30:37

       Why?

   17. SSSteve Stewart-Williams30:38

       Why is that sex difference? Uh, that is getting right into this, the central question of why there are any, any sex differences at all.

   18. CWChris Williamson30:45

       Yeah, I suppose we, we, we probably need to talk about-

   19. SSSteve Stewart-Williams30:47

       Yeah

   20. CWChris Williamson30:47

       ... like the evolution of sex differences, why they, why they exist in the first place.

   21. SSSteve Stewart-Williams30:50

       Yeah. Um, so we should jump to that. Uh, can I just, just as an aside, though, can I... We, we mentioned three of the six lines of evidence-

   22. CWChris Williamson30:59

       Yeah

   23. SSSteve Stewart-Williams30:59

       ... for innateness. Do we want to jump back and do the other three and then-

   24. CWChris Williamson31:01

       Sure

   25. SSSteve Stewart-Williams31:02

       ... maybe get into the-

   26. CWChris Williamson31:03

       Sure

   27. SSSteve Stewart-Williams31:03

       ... sort of thing? Um, so what do, what do we do? We had the developmental sex differences, we had the resistance to, uh, cultural pressure, we had the, um, persistence across time. So another one is, uh, hormonal correlates of sex differences, and in particular, um, you find associations between prenatal hormonal exposure and traits found later in life. Uh, so higher levels of testosterone in, in the womb, for instance, are associated with high levels of aggression later, high levels of risk-taking, lower levels of parental inclinations-

   28. CWChris Williamson31:41

       Mm

   29. SSSteve Stewart-Williams31:41

       ... um, a- and so on and so on.

   30. CWChris Williamson31:43

       And that's regardless of sex?
9. 39:44 – 42:18

   Is Parental Investment Damaging?

   1. CWChris Williamson39:44

      How does parental investment influence the evolution of sex differences?

   2. SSSteve Stewart-Williams39:49

      That is a major contributor. And the reason is that ... So, so this variance sex difference is mainly a, a result of sex differences and parental investment. So the reason that, um, some males can have many, many more offspring than any female in, in a lot of species is that females invest more in the young. So in mammals, for instance, to produce any one offspring, uh, a female has to have a, have a long pregnancy, has to give birth to the young, and then has to nurse the young, uh, for, for a while. Whereas, uh, a male to produce an offspring, just in principle o- only needs to, um, engage in, in one sex act.

   3. CWChris Williamson40:27

      Mm-hmm.

   4. SSSteve Stewart-Williams40:27

      So he can mate with multiple females and have tons of offspring because he invests potentially little in any given offspring.

   5. CWChris Williamson40:34

      Mm-hmm.

   6. SSSteve Stewart-Williams40:34

      Uh, whereas the females on the other hand, they invest a lot in th- each offspring. That lowers the ceiling for the number of offspring they can produce.

   7. CWChris Williamson40:41

      Therefore, you have to be choosier.

   8. SSSteve Stewart-Williams40:42

      You have to be choosier about your mates. Exactly. Sleeping with, uh, or, or mating with lots and lots of males, less useful for females than for males. Um, but ... So, so parental investment is really the core, um, to-

   9. CWChris Williamson40:55

      Is that the, is that the key driver?

   10. SSSteve Stewart-Williams40:58

       Uh, uh, well, I think the key driver is the difference in the maximum offspring number or, or the reproductive variance.

   11. CWChris Williamson41:03

       Right. And-

   12. SSSteve Stewart-Williams41:03

       Because it's not just shaped by parental investment

   13. CWChris Williamson41:05

       ... behaviorally that shows up as parental investment.

   14. SSSteve Stewart-Williams41:08

       Well, that's a big part of it. Yeah.

   15. CWChris Williamson41:09

       Yeah.

   16. SSSteve Stewart-Williams41:09

       So the parental investment is, is the major cause-

   17. CWChris Williamson41:13

       Yep

   18. SSSteve Stewart-Williams41:13

       ... of the sex difference in, in maximum offspring number.

   19. CWChris Williamson41:15

       Mm-hmm.

   20. SSSteve Stewart-Williams41:15

       But o- other things do come into it in different species.

   21. CWChris Williamson41:17

       Like gestation period too-

   22. SSSteve Stewart-Williams41:19

       Yep

   23. CWChris Williamson41:19

       ... is like a biological imposition on parental investment.

   24. SSSteve Stewart-Williams41:23

       Indeed.

   25. CWChris Williamson41:23

       Right. Well, uh, is, actually is, is how long it takes to just make a baby considered part of parental investment?

   26. SSSteve Stewart-Williams41:30

       That is part of parental investment, yeah.

   27. CWChris Williamson41:31

       Right.

   28. SSSteve Stewart-Williams41:32

       And parental care is, and nursing is.

   29. CWChris Williamson41:34

       Yep.

   30. SSSteve Stewart-Williams41:34

       Um-
10. 42:18 – 50:14

    Do Men Have Greater Reproductive Success?

    1. CWChris Williamson42:18

       Mm-hmm. Mm.

    2. SSSteve Stewart-Williams42:18

       Basically.

    3. CWChris Williamson42:19

       What's Bateman's principle?

    4. SSSteve Stewart-Williams42:20

       Bateman's principle? Um, so that is the idea that reproductive variance is greater in males than females in most species.

    5. CWChris Williamson42:27

       Right.

    6. SSSteve Stewart-Williams42:27

       And then Trivers', uh, sort of refinement of that was that the main cause of that is parental investment. So, so Bateman, uh, put it, put a, put a lot of it on anisogamy. He explained the difference in, in reproductive variance in terms of the fact that, um, females invest more per egg than males invest per sperm. Um, Trivers said, Robert Trivers, who died recently, he said, uh, "It's not just that. Actually it's, it's- All kinds of investment that you put into, into the young, not just the gametes, but also gestation and parturition, which is giving birth, uh, nursing, parental care, all those things-

    7. CWChris Williamson43:03

       Yeah

    8. SSSteve Stewart-Williams43:03

       ... um, are, are what matters. And, and I would just add that it's, uh, parental investment is the big one, but other things as well determine reproductive variance.

    9. CWChris Williamson43:11

       What is the ... It's about 40% of males, uh, of human males ancestrally reproducing about 80% of females. Is that right?

    10. SSSteve Stewart-Williams43:20

        I have heard that number bandied about. I actually think that probably in our species, my guess is that it's not, it's not that big. I've also seen other evidence suggesting that, um ... It's called reproductive skew-

    11. CWChris Williamson43:33

        Mm

    12. SSSteve Stewart-Williams43:33

        ... and suggesting the reproductive skew in our species is quite a bit lower than you find in most mammals. And I think the reason for that is that-

    13. CWChris Williamson43:41

        So the 40/80 number you think is, is wrong?

    14. SSSteve Stewart-Williams43:43

        Yeah.

    15. CWChris Williamson43:44

        Right. Okay.

    16. SSSteve Stewart-Williams43:44

        I think so. I think it's-

    17. CWChris Williamson43:44

        What's the, what's the reason?

    18. SSSteve Stewart-Williams43:45

        ... I think it's smaller. Uh, well, I think it's smaller, and I think because, uh, males in our species very often invest quite a lot in the, in the young.

    19. CWChris Williamson43:53

        Okay.

    20. SSSteve Stewart-Williams43:53

        So it's not just the sex act. Um, they often typically help out with the young as well. Uh, and so we have, we have high levels of biparental care-

    21. CWChris Williamson44:02

        Mm

    22. SSSteve Stewart-Williams44:02

        ... in our species.

    23. CWChris Williamson44:03

        Mm.

    24. SSSteve Stewart-Williams44:04

        That reduces the maximum offspring number for males rather to females-

    25. CWChris Williamson44:08

        Mm

    26. SSSteve Stewart-Williams44:08

        ... and brings it down, brings it closer to what we have for females.

    27. CWChris Williamson44:11

        So if other animals have less of a reproductive skew but also have less, uh, male parental investment, how would the reproductive skew for us be so great if we have more male parental investment? Is that what you're saying?

    28. SSSteve Stewart-Williams44:24

        That, that is what I'm saying.

    29. CWChris Williamson44:25

        Bingo.

    30. SSSteve Stewart-Williams44:25

        Yeah.
11. 50:14 – 54:34

    The Hidden Motivations Behind Behaviour

    1. CWChris Williamson50:14

       this is, uh, this is sort of my least... I don't know, actually. I, I, I probably could write out a hit list of my least favorite internet rebuttals to anyone talking about evolutionary theory, but one of them is a lack of understanding about the difference between proximate and ultimate, uh, motivations for behavior.

    2. SSSteve Stewart-Williams50:33

       Yeah. Yep, exactly. It's one of the big ones.

    3. CWChris Williamson50:35

       Yeah, like the-

    4. SSSteve Stewart-Williams50:36

       The big misunderstandings

    5. CWChris Williamson50:37

       ... why you feel the desire to do a thing, and the evolutionary advantage of you doing the thing, the fact that those two things are different. Um, you eat food because it tastes good-

    6. SSSteve Stewart-Williams50:52

       Yeah

    7. CWChris Williamson50:52

       ... but the reason for eating food is to keep you alive. Uh, you have sex because it feels good, but the reason to have sex is not the reason that it feels good.

    8. SSSteve Stewart-Williams51:01

       Exactly right. And, and it's quite annoying, right? When people say, "So you- you're saying that, um, like, sex and, uh, having, like, short-term relationships or long-term relationships is just about babies? But that can't be true, 'cause often the last people, the last thing people want is to have kids." And they use-

    9. CWChris Williamson51:16

       I don't want to have kids

    10. SSSteve Stewart-Williams51:16

        ... birth control.

    11. CWChris Williamson51:17

        I'd love to have sex.

    12. SSSteve Stewart-Williams51:18

        Yeah. Yeah, yeah, exactly, so it doesn't make sense, but they've just misunderstood the idea.

    13. CWChris Williamson51:21

        Yeah.

    14. SSSteve Stewart-Williams51:21

        'Cause it's not a psychological theory. Uh, like the, the genes I view explanations, the, the evolutionary explanations-

    15. CWChris Williamson51:28

        Mm-hmm

    16. SSSteve Stewart-Williams51:28

        ... th- those are not motivations. Those are just the explanations for why we have the m- the proximate psychological drives that we do.

    17. CWChris Williamson51:35

        Not the ultimate.

    18. SSSteve Stewart-Williams51:36

        Exactly.

    19. CWChris Williamson51:36

        Yeah, yeah. And, you know, w- with the, the... W- what's it referred to as, that theory of the sexual, not sexual value?

    20. SSSteve Stewart-Williams51:45

        Mm.

    21. CWChris Williamson51:46

        Of, of, uh, Darwin's daughter dying. What's the-

    22. SSSteve Stewart-Williams51:50

        Oh, uh, yeah. Uh, reproductive value.

    23. CWChris Williamson51:52

        Reproductive value.

    24. SSSteve Stewart-Williams51:53

        Yeah, yeah.

    25. CWChris Williamson51:54

        Uh, uh, no one is... Well, how horrible-

    26. SSSteve Stewart-Williams51:56

        Mm

    27. CWChris Williamson51:56

        ... to say to a parent, "Well, it's actually, M- M- Mrs. Thompson, the reason that your gri- Mrs. Darwin, the reason that your grief is so high is because of the reproductive value that your daughter almost didn't cash in on." Like, like-

    28. SSSteve Stewart-Williams52:08

        Exactly

    29. CWChris Williamson52:08

        ... horrible, horrible thing to say.

    30. SSSteve Stewart-Williams52:09

        Yeah.
12. 54:34 – 1:00:07

    Are Human Sex Differences Unique?

    1. SSSteve Stewart-Williams54:34

       care for others.

    2. CWChris Williamson54:34

       Yeah, yeah.

    3. SSSteve Stewart-Williams54:34

       Yeah, exactly, to be altruistic.

    4. CWChris Williamson54:35

       Okay, so I guess one, just to round out the... We haven't even got into the sex differences yet, which is the meat and potatoes of this, but I don't care.

    5. SSSteve Stewart-Williams54:41

       [laughs]

    6. CWChris Williamson54:41

       Um, is it, are, are humans unique in this regard? Because we've got mutual mate choice-

    7. SSSteve Stewart-Williams54:51

       Mm

    8. CWChris Williamson54:51

       ... and we've got biparental care. So when we're talking about evolution of sex differences, parental investment, ability to produce children, volume of children across a lifespan, Bateman's principle, varying some reproductive success, but humans do seem to be somewhat of an outlier in mammals and especially in the animal kingdom.

    9. SSSteve Stewart-Williams55:12

       Yeah. Yep

    10. CWChris Williamson55:14

        ... what wrinkle does that throw in?

    11. SSSteve Stewart-Williams55:17

        Uh, well, yeah. So we are ... So the question are we unique? Sort of yes and no. So the way in which we are unique, we're very unique among mammals, like you say, in the fact that we have high levels of the tendency to pair bond, so to fall in love and form relatively durable pair bonds, and for both sexes rather than just the females to invest in the young. Um, that is found in maybe 5 to 10%, 10% at the most, of mammals. Um, so the overwhelming trend among mammals is that the females do all the investment in the young, and the males are basically deadbeat dads. Uh, in birds, on the other hand, they are an outlier family of animals among animals in general-

    12. CWChris Williamson55:58

        Mm

    13. SSSteve Stewart-Williams55:58

        ... in that around 90% of birds form pair bonds and have biparental care.

    14. CWChris Williamson56:02

        Mm-hmm.

    15. SSSteve Stewart-Williams56:03

        And so there's a funny thing, and I find this, uh, just very, very interesting, is that in our primary reproductive behavior, humans are more like the average bird than like the average mammal.

    16. CWChris Williamson56:13

        No way.

    17. SSSteve Stewart-Williams56:14

        Yeah. That's because of our pair bonding and our biparental tendencies.

    18. CWChris Williamson56:16

        Which is a, uh, reinforcement that the parental investment i- is the key driver of sex differences?

    19. SSSteve Stewart-Williams56:28

        Yeah. Yep, exactly. Um, and, and are they, um-

    20. CWChris Williamson56:30

        [laughs] That's fucking hilarious

    21. SSSteve Stewart-Williams56:31

        ... it's an amazing one

    22. CWChris Williamson56:32

        ... because most birds... Oh, hang on a second.

    23. SSSteve Stewart-Williams56:33

        Yeah, yeah.

    24. CWChris Williamson56:33

        So most birds are kind of like dinosaurs, and humans are closer to birds than they are to most mammals-

    25. SSSteve Stewart-Williams56:41

        Yep

    26. CWChris Williamson56:42

        ... which means that humans are kind of dinosaurs.

    27. SSSteve Stewart-Williams56:44

        Yeah, so, so we're mammals-

    28. CWChris Williamson56:44

        That's by evolutionary logic

    29. SSSteve Stewart-Williams56:45

        ... that's great. That's great. Do you want this or ...

    30. CWChris Williamson56:47

        Yes. No, no, I don't need that. I don't need that.
13. 1:00:07 – 1:03:20

    Is It All About Reproducing?

    1. SSSteve Stewart-Williams1:00:07

       females.

    2. CWChris Williamson1:00:07

       All right, meat and potatoes.

    3. SSSteve Stewart-Williams1:00:08

       Yeah.

    4. CWChris Williamson1:00:08

       Getting back to sex differences and sex drive.

    5. SSSteve Stewart-Williams1:00:11

       Yeah.

    6. CWChris Williamson1:00:12

       What... Casual sex, sexual variety, cheating, uh, uh, what's going on there?

    7. SSSteve Stewart-Williams1:00:16

       Yep. Uh, that's all about producing more offspring. So, um, a male that is equipped with those motivations is gonna be sort of like a heat-seeking missile going out to seek multiple, uh, partners-

    8. CWChris Williamson1:00:29

       Right

    9. SSSteve Stewart-Williams1:00:29

       ... uh, and is, is therefore more likely to have, um, more offspring if, if he's successful than that-

    10. CWChris Williamson1:00:36

        Hmm

    11. SSSteve Stewart-Williams1:00:37

        ... than he would if he just sort of sat back and was, wasn't interested in multiple partners.

    12. CWChris Williamson1:00:41

        Right.

    13. SSSteve Stewart-Williams1:00:41

        And, and you do find that in many species. Now, I don't think that the difference is as big in our species as in many others, and I think that's a side effect of the fact that because we have biparental care, the level of reproductive variance among males in our species is somewhat constrained, still greater than among females. But because it's somewhat constrained, sex differences in our species have correspondingly come down as well.

    14. CWChris Williamson1:01:04

        Hmm.

    15. SSSteve Stewart-Williams1:01:04

        So we still have all the traditional sex differences, uh, that you find in, in most mammals and many other species, but they're somewhat muted. So you have the, the sexuality sex differences, uh, but they're somewhat muted. The aggression, uh, differences, but they're somewhat muted. Um- Uh, uh, the parenting differences, uh, is the main source of this

    16. CWChris Williamson1:01:24

        Mm

    17. SSSteve Stewart-Williams1:01:24

        So that, you know, is, uh, like, uh, the discrepancy in male investment in kids versus female investment has, has been massively reduced

    18. CWChris Williamson1:01:31

        And that's the driver

    19. SSSteve Stewart-Williams1:01:32

        And that's the, that's the driver

    20. CWChris Williamson1:01:33

        The bi-parental-

    21. SSSteve Stewart-Williams1:01:34

        Yeah

    22. CWChris Williamson1:01:34

        ... the bi-parental investment is the nerfing-

    23. SSSteve Stewart-Williams1:01:37

        Yeah

    24. CWChris Williamson1:01:37

        ... the reason for the nerfing of all of the others. Okay, again, I, I'm only gonna make this fucking disclaimer once, uh, but we said it, we said it previously, but I think it's worth saying again. Just because we can explain using evolutionary logic the reason why men might be driven to cheat more than women is not the same thing as excusing why it happens.

    25. SSSteve Stewart-Williams1:01:58

        No, not at all, any more than, um, a sociocultural explanation would excuse it. But that's the funny asymmetry. People seem to think if you explain it in evolutionary terms, that excuses it, but there's no more reason to assume that than to assume that if you explain it in sociocultural terms, it excuses it.

    26. CWChris Williamson1:02:11

        Because with both of those you are, um, outsourcing the culpability of the individual to something else.

    27. SSSteve Stewart-Williams1:02:19

        Yeah.

    28. CWChris Williamson1:02:19

        In one it's evolution-

    29. SSSteve Stewart-Williams1:02:20

        Yeah

    30. CWChris Williamson1:02:20

        ... and ancestors, and in the other it's culture and influence.
14. 1:03:20 – 1:11:44

    Why Women Prefer Reading Porn

    1. SSSteve Stewart-Williams1:03:20

       [laughs] Yeah.

    2. CWChris Williamson1:03:20

       Um, what about men being more turned on by visual triggers?

    3. SSSteve Stewart-Williams1:03:23

       Uh, yeah, that's another, another big sex difference. Um, both sexes are to some degree. You know, both sexes are interested in good looks in a mate, but it's stronger in men than in, in women. And the main reason for that is that the traits that we consider good-looking are associated with, with youthfulness and fertility-

    4. CWChris Williamson1:03:40

       Mm

    5. SSSteve Stewart-Williams1:03:40

       ... for both sexes. Um, but men place a greater weight on those traits becau- because of menopause, basically.

    6. CWChris Williamson1:03:47

       Mm.

    7. SSSteve Stewart-Williams1:03:47

       So the fact that, um, they, they place more weight on youthfulness in a mate because youthfulness is more closely linked to fertility in women than men because of the fact that women's fertility shuts off about, you know, uh, two-thirds of the, of the way through the lifespan.

    8. CWChris Williamson1:04:01

       Mm-hmm.

    9. SSSteve Stewart-Williams1:04:02

       Yeah. So yeah, so men are much more interested in visual sexual stimuli, as psychologists call it. It's part of the explanation for the fact that, um, men are much more avid consumers of porn-

    10. CWChris Williamson1:04:12

        Mm

    11. SSSteve Stewart-Williams1:04:13

        ... than women are.

    12. CWChris Williamson1:04:14

        What is the reason that women are much more avid consumers of romantasy and romance novels than men?

    13. SSSteve Stewart-Williams1:04:21

        It's, it's an interesting one, isn't it? So that's the, the standard sort of differences in consumer preferences that we hear about. Men are much more into porn than women. Women are much more into romance novels. Um, now, now it is interesting. We've, we've talked about the fact that men on average are more interested in casual sex than women, and people often assume that the flip side of that is true as well, that women are more interested in long-term relationships than men. But actually that's not the case. Uh, typically what we find is that men and women are about as interested as, as each other in long-term committed relationships, in falling in love and forming a committed bond with, with a partner.

    14. CWChris Williamson1:04:57

        So you haven't reapportioned the sex drive, relationship drive desire from short-term to long-term for women-

    15. SSSteve Stewart-Williams1:05:06

        No

    16. CWChris Williamson1:05:06

        ... it's just that they don't have this addition that men do-

    17. SSSteve Stewart-Williams1:05:10

        Yeah

    18. CWChris Williamson1:05:10

        ... of the one-night stand.

    19. SSSteve Stewart-Williams1:05:12

        Exactly right. But bearing that in mind-

    20. CWChris Williamson1:05:13

        To the same degree.

    21. SSSteve Stewart-Williams1:05:14

        Yeah, yeah, yeah. Uh, bearing that in mind, uh, the, the fact that women are so much more interested in romance novels is interesting and sort of s- slightly unexpected. You would... You might expect that both sexes would be interested in them. Um, so, so why it is the case that women are more interested in them, I guess evolutionarily speaking, I, I don't know. They, they do seem to be, despite the fact that actually men do seem to be very invested in long-term relationships. A bunch of papers have come out recently actually saying that in, in a lot of ways men are kind of more, more romantic than women.

    22. CWChris Williamson1:05:47

        Mm-hmm.

    23. SSSteve Stewart-Williams1:05:47

        They are more likely to suffer after a breakup. Uh-

    24. CWChris Williamson1:05:49

        Fall in love more quickly-

    25. SSSteve Stewart-Williams1:05:50

        Yeah, exactly

    26. CWChris Williamson1:05:50

        ... say I love you more soon.

    27. SSSteve Stewart-Williams1:05:52

        Exactly. Exactly. So why aren't they more into romance novels? I don't know. Maybe they're just too busy with the, with the porn.

    28. CWChris Williamson1:05:57

        Yeah.

    29. SSSteve Stewart-Williams1:05:58

        But...

    30. CWChris Williamson1:05:58

        Uh, [laughs] yeah, true. I... Dude, I mean, I, I sat next to a lady, lovely lady, floral dress, slightly, slightly older lady-
15. 1:11:44 – 1:14:13

    Are Men and Women Compromising On Sex?

    1. SSSteve Stewart-Williams1:11:44

       Yeah. Yeah, yeah.

    2. CWChris Williamson1:11:44

       Sex differences. All right. How do, um, how do gay men and lesbians reveal what each sex wants?

    3. SSSteve Stewart-Williams1:11:49

       They do so in a very interesting way, which is that, um, gay men have more casual sex than straight men, and lesbians have less casual sex than straight women. Uh, and the reason is that gay men and lesbians don't have to compromise with the typical sexual inclinations of the other sex.

    4. CWChris Williamson1:12:07

       Mm-hmm.

    5. SSSteve Stewart-Williams1:12:08

       And they can... Therefore their behavior is like a clearer window onto the, the sexual motivations of men and women in general.

    6. CWChris Williamson1:12:15

       Unsullied by the other sex.

    7. SSSteve Stewart-Williams1:12:17

       Ex- exactly, yeah. So men are compromising by having less because basically women are thwarting their plans.

    8. CWChris Williamson1:12:22

       Yep.

    9. SSSteve Stewart-Williams1:12:23

       Whereas-

    10. CWChris Williamson1:12:23

        There's no gatekeeper

    11. SSSteve Stewart-Williams1:12:24

        ... it is [laughs] exactly. And, uh, yeah, whereas straight women are compromising with men and maybe having more than, more, uh, casual sex than they would choose-

    12. CWChris Williamson1:12:32

        Hmm

    13. SSSteve Stewart-Williams1:12:33

        ... uh, at least as revealed by, yeah, lesbian behavior.

    14. CWChris Williamson1:12:35

        There's, uh, an interesting study that Rob brought up, which was, uh, inside of marriages, typically men say that they would like to have twice as much sex as they are having, and women say that they are happy with the amount of sex that they are having-

    15. SSSteve Stewart-Williams1:12:49

        Yeah

    16. CWChris Williamson1:12:49

        ... which suggests that there is a compromise going on.

    17. SSSteve Stewart-Williams1:12:52

        Yeah.

    18. CWChris Williamson1:12:52

        Uh, but that the compromise is basically [laughs] -

    19. SSSteve Stewart-Williams1:12:54

        The guy going, "Okay, fine, man." [laughs]

    20. CWChris Williamson1:12:56

        Yeah.

    21. SSSteve Stewart-Williams1:12:56

        She's setting, she's setting the level-

    22. CWChris Williamson1:12:57

        She's setting them up-

    23. SSSteve Stewart-Williams1:12:58

        ... more than he is

    24. CWChris Williamson1:12:58

        ... with that regard.

    25. SSSteve Stewart-Williams1:12:59

        Yeah. Yeah.

    26. CWChris Williamson1:12:59

        Uh, I do think that there's kind of a... And this is, I mean, like are we really gonna say boo-hoo poor men not getting exactly what they want? But I do think that it's a, a kind of compromise that might be invisible to women-

    27. SSSteve Stewart-Williams1:13:17

        Hmm

    28. CWChris Williamson1:13:17

        ... because sexual entitlement comes wrapped in some really ugly, uh, paper. But there is an argument that you can make there to say something like, look, men are doing a type of containment, a type of desire containment there that isn't a, a burden that is-

    29. SSSteve Stewart-Williams1:13:36

        Yeah

    30. CWChris Williamson1:13:37

        ... that they are paying, that isn't Being paid in the same way inside of a marriage by the woman and, huh, that's, uh, we... Well done. Well done for doing that.
16. 1:14:13 – 1:16:55

    How Similar Are Male and Female Mate Preferences?

    1. CWChris Williamson1:14:13

       Okay. So mate preferences.

    2. SSSteve Stewart-Williams1:14:15

       Yes.

    3. CWChris Williamson1:14:15

       When it comes to mate preferences, is it surprising how similar men and women are when it comes to what they look for in a partner?

    4. SSSteve Stewart-Williams1:14:25

       Uh, well, I guess it fits with the generalization that in a lot of ways we are quite similar, that we, the sex differences in our species are not as huge as, as in some others. And I guess also just on a, um, everyday level, when, when you hear about some of the sex differences that we have in common, they're all things that I think it's, it's obvious why we like them. Uh, people tend to be, uh, men and women tend to want somebody, uh, who's pretty intelligent and who's kind and who loves them and who is attracted to them and who is pretty good-looking, um, and who's not, uh, like s- mentally unstable.

    5. CWChris Williamson1:15:02

       Yeah.

    6. SSSteve Stewart-Williams1:15:02

       Uh, both sexes want that, not just men, not just women. Um, there are some areas though where you do find the sex differences and the strength of different preferences. So, uh, both sexes want someone who's pretty good-looking, for instance. Um, but on average, in long-term relationships, that's a bigger deal for men than for women.

    7. CWChris Williamson1:15:19

       Mm-hmm.

    8. SSSteve Stewart-Williams1:15:20

       Uh, men put more weight on looks in a mate, um, than in a long-term mate than, than women do for the reasons that I mentioned-

    9. CWChris Williamson1:15:26

       Mm

    10. SSSteve Stewart-Williams1:15:26

        ... that I mentioned earlier. Uh, women on the other hand tend to put more weight on resources and status in a long-term mate, uh, than men do.

    11. CWChris Williamson1:15:36

        Mm.

    12. SSSteve Stewart-Williams1:15:37

        Um, now, now in neither of those cases is, is that the... It's not like looks are the most important thing to most men. For most men, it's, it's important, but other things are equally important or even more important.

    13. CWChris Williamson1:15:48

        Mm.

    14. SSSteve Stewart-Williams1:15:48

        Traits like kindness. And likewise with women, um, resources and status in a mate, they're, they're important, but other things, like again, like kindness, uh, tend to top the list of the things that are most important for women.

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17. 1:16:55 – 1:21:55

    How Status and Wealth Shape Attraction

    1. CWChris Williamson1:16:56

       What's the evolutionary logic of non-physical mate preferences like wealth and status?

    2. SSSteve Stewart-Williams1:17:01

       It all comes down, I think, to the fact... Well, there are two main explanations for it. Uh, so one is that it's part of our evolution of a pair bonding biparental species. So a guy who is able to access resources, you know, uh, bring in food, uh, and, and also has good standing within the group, that's gonna be someone who is better able to invest in the young, to co-rear the children. Uh, and that's the explanation I think is most popular and most likely. Um, there is also an explanation though that it's primarily a human equivalent of the peacock's tail, so that any, any male that is capable of bringing in resources and climbing the status hierarchy, that's a male who's got good genes and, uh, he's gonna pass on whatever traits enabled him to do that to his male offspring. They're gonna be able to do the same. They're gonna attract more mates.

    3. CWChris Williamson1:17:49

       Mm.

    4. SSSteve Stewart-Williams1:17:50

       Uh, so th- those are the two main explanations. Uh, I think it's quite possible that both of them shed light on it, that, that it's both a, uh, a fitness indicator-

    5. CWChris Williamson1:17:58

       Mm

    6. SSSteve Stewart-Williams1:17:58

       ... but also is actually useful in the context of, uh, biparental care.

    7. CWChris Williamson1:18:01

       You mentioned this is to do with long-term relationships.

    8. SSSteve Stewart-Williams1:18:05

       Yeah.

    9. CWChris Williamson1:18:06

       How does this change when it comes to short-term relationships? Do women place more or closer to equal, uh, weight on physical attractiveness in men?

    10. SSSteve Stewart-Williams1:18:15

        They do. They do, yeah.

    11. CWChris Williamson1:18:17

        Okay.

    12. SSSteve Stewart-Williams1:18:17

        So that sex difference in good looks, uh, we sometimes hear it discussed as if that's a difference between men and women right across the board in every context.

    13. CWChris Williamson1:18:25

        Right.

    14. SSSteve Stewart-Williams1:18:25

        Uh, but actually it does just apply to long-term relationships, and when it comes to low commitment relationships, um, then that, that difference basically evaporates, and women are at least as interested in physical attractiveness in a mate, uh, as men are. If not, you know, some research suggesting maybe even more interested in physical attractiveness.

    15. CWChris Williamson1:18:43

        Why would that be the case using evolutionary logic?

    16. SSSteve Stewart-Williams1:18:45

        Because... Well, the, the best explanation is that in a short-term context, that's likely to be, um, uh, basically there's gonna be no further investment probably.

    17. CWChris Williamson1:18:57

        Hmm.

    18. SSSteve Stewart-Williams1:18:58

        Uh, likely no further investment. The only investment is the genes that the male is going to be passing on, and therefore traits that are indicative of good genes are much more important. They, they take center stage in terms of what, what women are looking for.

    19. CWChris Williamson1:19:12

        Uh-huh.

    20. SSSteve Stewart-Williams1:19:13

        And, um, and, and yeah, with the, the basic evolutionary logic that, uh, when you're reproducing, you are finding somebody to mix your genes with.

    21. CWChris Williamson1:19:21

        Hmm.

    22. SSSteve Stewart-Williams1:19:22

        If you want your genes to go on in the gene pool, uh, you got to mix them with a good set of genes from-

    23. CWChris Williamson1:19:28

        Yeah

    24. SSSteve Stewart-Williams1:19:28

        ... from another individual.

    25. CWChris Williamson1:19:29

        And what you want, if it's you, you have a, a short window to do this assessment and you want the most obvious representation of those good genes as you can.

    26. SSSteve Stewart-Williams1:19:37

        Exactly. And, and physical looks are the, are that.

    27. CWChris Williamson1:19:39

        I'm sorry, your ability to do- non-kin altruism and reciprocal care and, and kindness and your ambition over time. It's like, yeah, great, but I don't have time-

    28. SSSteve Stewart-Williams1:19:50

        Yeah

    29. CWChris Williamson1:19:50

        ... to assess that in the same way-

    30. SSSteve Stewart-Williams1:19:52

        Yeah, yeah. Okay
18. 1:21:55 – 1:29:21

    Would Women Sleep With Their Ideal Sperm Donor?

    1. CWChris Williamson1:21:55

       Have you seen, I think it's Andrew Thomas that did this study. Have you seen the preferences that women state when it comes to sperm donors?

    2. SSSteve Stewart-Williams1:22:08

       Yeah.

    3. CWChris Williamson1:22:08

       So this is fucking fascinating-

    4. SSSteve Stewart-Williams1:22:10

       Yeah

    5. CWChris Williamson1:22:10

       ... because what's interesting is when you run a, a, a kind of a split test or you're able to separate out certain motivations from, uh, a, a behavior that people are typical with. So in order for you to do the, "I want to have kids with this person," typically you need to go through courtship phase and get to know them and... Or even if it's a one-night stand, be seduced by them.

    6. SSSteve Stewart-Williams1:22:32

       Yeah.

    7. CWChris Williamson1:22:32

       But that means that you're optimizing for two different things. You're not just optimizing for the genes that your kid gets, you're also optimizing for the expression of traits that make you want to get into bed with somebody. But if you get rid-

    8. SSSteve Stewart-Williams1:22:47

       Right

    9. CWChris Williamson1:22:47

       ... of the seduction side of this, all you're optimizing for is, what do I want my kids to have from a trait perspective?

    10. SSSteve Stewart-Williams1:22:53

        Yeah.

    11. CWChris Williamson1:22:53

        And that difference of when you get rid of the need to actually be attracted to somebody and you can just optimize for, what do I want my kids to be like?

    12. SSSteve Stewart-Williams1:23:01

        Yep.

    13. CWChris Williamson1:23:02

        Kind of fascinating.

    14. SSSteve Stewart-Williams1:23:03

        It's really fascinating, right? And, and just the same mate preferences emerge in that context as emerge in an actual, uh, interaction, social interactions.

    15. CWChris Williamson1:23:11

        Hmm. It was that Clark Hatfield study as well, right? The on-the-street interview.

    16. SSSteve Stewart-Williams1:23:16

        Yeah. Yeah, that's the one where, um, uh, basically they got a bunch of good-looking guys, good-looking gals to go around a campus on a nice day, uh, walk up to random people on the campus and just say, "Hello, how are you doing? Um, I've noticed you around the place lately, and I find you very attractive, and I was just wondering whether you wanted to..." Dot, dot, dot. And then they would finish that sentence with one of three options. Option number one was, "I was wondering if you wanted to go out with me tonight?" Option number two was, "I was wondering if you wanted to come up to my room?" And option number three was, "I'm wondering, wondering if you wanted to go to bed with me?" And they got men to ask women, women to ask men. And the, for the, um, for the ques- first question, the go out with me question, there... In, in the first study they did, there was basically no sex difference. So it was about 50%, 50/50 likelihood of saying yes in both cases. Uh, other replication studies have found that it's not a huge difference, but that actually men are more likely to say yes than women are. But then with the other two questions, the gaps get bigger and bigger. With question number two, which is, "Would you want to come up to my room?" Um, what was it? It was basically 67... In the first study, about 67% of men said yes. So actually higher than the date rate. [laughs]

    17. CWChris Williamson1:24:31

        [laughs] More likely to go up to your room than I am to go on a date with you.

    18. SSSteve Stewart-Williams1:24:33

        Exactly.

    19. CWChris Williamson1:24:34

        That's hilarious.

    20. SSSteve Stewart-Williams1:24:35

        Uh, with women on the other hand, it, uh, sank down to, I, I believe it was 6% said yes to that. Uh, and then the gap was even bigger for the last question, unsurprisingly. So would you go to bed with me? 75% of men said yes, uh, to that offer, so an even higher rate of men. [laughs] Whereas, uh, exactly 0% of women said yes to the, the kind offer. And not only that, but actually the, the manner of the refusal differed between men and women. So of the, um, 25% of men who said, "Thanks, but no thanks," well, they kind of said that. They were, like, polite about it. And, uh, some of them said, "I'm really sorry, I'm, I'm meeting my fiancé" or whatever. A bunch of them even asked for a rain check, apparently. They said, "I can't. I'm very busy. I'm meeting my fiancé" or whatever-

    21. CWChris Williamson1:25:20

        Hmm

    22. SSSteve Stewart-Williams1:25:20

        ... "but maybe we could postpone the sex till later." Whereas, uh, none of the women, uh, who were refusing were polite about it at all. They were more... They were... reacted more like, "Are you crazy?"

    23. CWChris Williamson1:25:30

        Yeah.

    24. SSSteve Stewart-Williams1:25:31

        Um, "How d- how dare you ask me that?"

    25. CWChris Williamson1:25:33

        Hmm.

    26. SSSteve Stewart-Williams1:25:33

        None of them, um, apologized and asked for a rain check.

    27. CWChris Williamson1:25:36

        Why do you think that the manner of refusal was so different?

    28. SSSteve Stewart-Williams1:25:41

        Uh, I think that- It reveals, uh, well, t-two reasons. So one is there's this average difference in interest in casual sex.

    29. CWChris Williamson1:25:49

        Mm.

    30. SSSteve Stewart-Williams1:25:49

        And because men are more interested in it, they are more likely to be flattered by the request, uh, because men are much more likely to approach women than vice versa.
19. 1:29:21 – 1:37:34

    Why Are Women Attracted to Dangerous Men?

    1. CWChris Williamson1:29:21

       What about sex differences in aggression?

    2. SSSteve Stewart-Williams1:29:23

       Sex differences in aggression are very, very consistent, um, especially for direct aggression, so face-to-face aggression, and guys predominate. And a really interesting fact about the aggression sex difference is that it's, it's, for, like, verbal aggression, it's there and it's significant. It's fairly modest, though. So the effect size might be about, like, a 0.5 effect size, so half a standard deviation between the mean for men, men and women. And maybe, you know, pluck two people at random, uh, a guy and a gal, two-thirds of the time the guy's gonna be higher in verbal aggression. But as you go further out to more and more intense forms of aggression-

    3. CWChris Williamson1:29:59

       Mm

    4. SSSteve Stewart-Williams1:29:59

       ... the size of the sex difference gets bigger and bigger with every step. So when you go to low levels of physical aggression, slapping, pushing, that kind of thing, that, uh, you have a, a larger sex difference, men doing it more. Then you get into serious physical aggression, violent crime, m- that's much more men than women.

    5. CWChris Williamson1:30:16

       This is independent of who the victim is?

    6. SSSteve Stewart-Williams1:30:18

       Independent of who the victim is.

    7. CWChris Williamson1:30:19

       Yep, yep.

    8. SSSteve Stewart-Williams1:30:20

       Is, yeah.

    9. CWChris Williamson1:30:20

       Yeah.

    10. SSSteve Stewart-Williams1:30:21

        Um, and then when you get to the extreme of one-on-one aggression, which is homicide, uh, men vastly predominate. So across different, uh, cultures, every single nation, uh, every data set I've, I've ever seen, 90-plus percent of homicides are perpetrated by men. Men are also the, the, the majority of the victims as well-

    11. CWChris Williamson1:30:39

        Mm

    12. SSSteve Stewart-Williams1:30:39

        ... in, in almost all data sets that I've seen.

    13. CWChris Williamson1:30:42

        Mm.

    14. SSSteve Stewart-Williams1:30:42

        Um, but, but yeah, the 90%-plus perpetrators, very, very strong effect.

    15. CWChris Williamson1:30:48

        Yeah. Uh, men commit more than 90% of homicides in every society on Earth where data is available, and this gap is remarkably invariant across cultures-

    16. SSSteve Stewart-Williams1:30:55

        Yeah

    17. CWChris Williamson1:30:55

        ... not just the absolute rates. In humans, males commit 95% of homicides and are 70% to 80% of homicide victims. In chimpanzees, male commit 92% of chimpcides-

    18. SSSteve Stewart-Williams1:31:06

        [laughs]

    19. CWChris Williamson1:31:06

        ... and are 73% of victims, virtually identical numbers to humans.

    20. SSSteve Stewart-Williams1:31:10

        It's wild, right? Yeah. Now, they are more aggressive than us. I think some- sometimes people hear that and they think that the claim is that we're just as aggressive as chimps-

    21. CWChris Williamson1:31:17

        No, we're way more aggressive

    22. SSSteve Stewart-Williams1:31:17

        ... but they are more. But the size of the sex diff- difference in lethal aggression-

    23. CWChris Williamson1:31:21

        Mm

    24. SSSteve Stewart-Williams1:31:21

        ... is the same. And the size of the, the targets, the sex difference in the targets of aggression is about the same as well.

    25. CWChris Williamson1:31:27

        Why?

    26. SSSteve Stewart-Williams1:31:28

        Uh, that is a direct offshoot of the fact that, um, it's, it's the selection for getting to be one of the few males that has many offspring rather than the many that have few or none, and one of the ways that males do that is they compete with each other, uh, for status and resources. Uh, which increase their mating opportunities. And so you get selection in many, many species, not just humans, selection for greater aggression, uh, in the males and, and particularly for greater male-male aggression, which is why you have this, this skew toward not only to other males more aggressive, but the targets of their aggression tend to be same-sex individuals as well. For women and for female m- uh, animals in general, they are capable of aggression in many species, but there's just less of a selection pressure. It's less, it's less useful for them evolutionarily-

    27. CWChris Williamson1:32:19

        Hmm

    28. SSSteve Stewart-Williams1:32:19

        ... to engage in same-sex combat-

    29. CWChris Williamson1:32:23

        Yeah

    30. SSSteve Stewart-Williams1:32:23

        ... for status and resources because of the fact that the, the ceiling offspring number f- that they have is lower, so they can't vastly increase the number of offspring they have by fighting each other and getting lots of status, resources, and ultimately mates. You know, that, that won't boost the number of offspring they have because the ceiling is lower. So it's, it's costlier for them. The costs aren't worth the risks.
20. 1:37:34 – 1:40:25

    Is Height Really That Important?

    1. SSSteve Stewart-Williams1:37:34

       right? There's-

    2. CWChris Williamson1:37:34

       Why is it, why is it that women care more about a man's height than women do? Does it play into this?

    3. SSSteve Stewart-Williams1:37:39

       Uh, I think it probably is. I think it must be. I think it's the sa- within a cluster of traits that determine protectiveness and the like. Mus- muscularity, height, they, they're all part of the same package.

    4. CWChris Williamson1:37:48

       Hmm.

    5. SSSteve Stewart-Williams1:37:49

       And it's interesting, right? They just seem to be really, really high on the list for women. Seems to be very important.

    6. CWChris Williamson1:37:54

       You know why this makes the most sense? And it's the probably- Yeah, I would, I would go as far as to say it's the most commonly cited, "Well, you bitches" i- internet kind of rebuttal that guys have around... I think, uh, Tinder released as an April Fool's joke about 10 years ago-

    7. SSSteve Stewart-Williams1:38:16

       Mm

    8. CWChris Williamson1:38:16

       ... a height filter-

    9. SSSteve Stewart-Williams1:38:18

       Mm

    10. CWChris Williamson1:38:18

        ... that people could use. Like, "Wouldn't it be funny if we gave you a height filter?"

    11. SSSteve Stewart-Williams1:38:21

        Yeah.

    12. CWChris Williamson1:38:21

        That's now an actual feature.

    13. SSSteve Stewart-Williams1:38:22

        It's an actual feature, right?

    14. CWChris Williamson1:38:23

        Yeah. Um, and, uh, many women don't need to date or d- don't want to date men that are under six feet, uh, especially not men when you get sort of like 5'7", 5'6", 5'5", like very few would. And I had this insight, the tall girl problem, uh, and it was born out of a friend whose sister is 5'2" ... Uh, sorry, her sister's 5'11". Um, so she wants to wear heels on her wedding day. She's like-

    15. SSSteve Stewart-Williams1:38:49

        Right

    16. CWChris Williamson1:38:49

        ... a professional athlete.

    17. SSSteve Stewart-Williams1:38:50

        Yep.

    18. CWChris Williamson1:38:51

        And they were going around the supermarket and she saw this guy who was like 6'5", like tall dude, like you, tall guy, and she sort of nudges her sister and says, like, "I might go up, I might go up and talk to him." And they round the corner and they say- see him with this 5'2" Latina bombshell and she kicks off at her sister quietly, uh, and says like, "This fucking bitch."

    19. SSSteve Stewart-Williams1:39:17

        Yeah.

    20. CWChris Williamson1:39:17

        "Like she could date 5'5", 5'6", 5'7". Why'd you have to take a guy that's a foot and a half taller than her?"

    21. SSSteve Stewart-Williams1:39:23

        Taller than her.

    22. CWChris Williamson1:39:23

        But the point here is if we're talking about protectiveness-

    23. SSSteve Stewart-Williams1:39:28

        Yeah

    24. CWChris Williamson1:39:28

        ... as the driver-

    25. SSSteve Stewart-Williams1:39:29

        Yeah

    26. CWChris Williamson1:39:29

        ... the fact that your chick is a 5'2" Latina, not a 5'11" American, does not make your height any more or less useful when it comes to protectiveness. I don't need to protect you less just because you're smaller.

    27. SSSteve Stewart-Williams1:39:45

        Yeah. Yeah, yeah. [laughs] Indeed.

    28. CWChris Williamson1:39:46

        You know?

    29. SSSteve Stewart-Williams1:39:47

        Yeah.

    30. CWChris Williamson1:39:47

        And this is why I think you don't see much of a height compensation effect-
21. 1:40:25 – 1:46:54

    Do Men Actually Talk More Than Women?

    1. CWChris Williamson1:40:25

       man? Uh, all right, sex differences in stalking, what about that?

    2. SSSteve Stewart-Williams1:40:29

       Uh, women do a lot more of it. Joke. Men do a lot more of it. [laughs]

    3. CWChris Williamson1:40:34

       [laughs]

    4. SSSteve Stewart-Williams1:40:35

       Uh, men do a lot more of it. It's, I think it's just, um, an example of this, the fact that men are more, you know, proactive, seeking out mates or seeking out multiple mates. Uh, and stalking is the subcategory of that when it gets into extremely i- inappropriate examples of that.

    5. CWChris Williamson1:40:50

       Mm.

    6. SSSteve Stewart-Williams1:40:50

       Um, and also I guess, uh, yeah, it's also it's not just mate seeking, it's also when people get fixated on somebody.

    7. CWChris Williamson1:40:58

       Yep.

    8. SSSteve Stewart-Williams1:41:00

       And both sexes can do that. They can get fixated on somebody-

    9. CWChris Williamson1:41:02

       Sort of limerence type thing

    10. SSSteve Stewart-Williams1:41:03

        ... fall in love... Yeah, yeah, exactly. Limerence, yeah. So sort of falling in love except that, uh, we call it limerence 'cause it's in a, in a, an inappropriate circumstance, i.e. a circumstance where the other person does not reciprocate. Both sexes can do it, but men are more prone to aggression and risk-taking and just bad behavior.

    11. CWChris Williamson1:41:20

        Yep.

    12. SSSteve Stewart-Williams1:41:20

        And so they're more likely to do more of th- those kind of behaviors in the context of, uh, of limerence and being fixated on somebody.

    13. CWChris Williamson1:41:27

        What about surveillance? Surveilling of-

    14. SSSteve Stewart-Williams1:41:29

        Yeah

    15. CWChris Williamson1:41:30

        ... a partner, checking in, because I could see two, two reasons why either side might be doing it more. Uh, male parental uncertainty, which we haven't talked about yet-

    16. SSSteve Stewart-Williams1:41:40

        Yeah

    17. CWChris Williamson1:41:40

        ... but is super important.

    18. SSSteve Stewart-Williams1:41:41

        Yeah.

    19. CWChris Williamson1:41:42

        That no woman has ever given birth to a child and wondered whether it was hers.

    20. SSSteve Stewart-Williams1:41:45

        Yeah.

    21. CWChris Williamson1:41:45

        But many men have looked at, maybe even all, all men to some degree. In fact it would be evolutionary, uh, useful for you-

    22. SSSteve Stewart-Williams1:41:52

        Yeah

    23. CWChris Williamson1:41:52

        ... the first time that you look at your kid to be, uh, so beautiful and are those my eyes?

    24. SSSteve Stewart-Williams1:41:57

        Yeah.

    25. CWChris Williamson1:41:57

        Yeah, I think they're my eyes.

    26. SSSteve Stewart-Williams1:41:58

        [laughs]

    27. CWChris Williamson1:41:58

        Um, uh, but given the fact that you have high male parental uncertainty-

    28. SSSteve Stewart-Williams1:42:03

        Yeah

    29. CWChris Williamson1:42:03

        ... because you've got concealed ovulation and you don't have the same kind of sort of harem hermetically sealed sphere when it comes to men and women, human-

    30. SSSteve Stewart-Williams1:42:12

        Yeah
22. 1:46:54 – 1:52:11

    Why Do Men Choose to Be Sexually Violent?

    1. CWChris Williamson1:46:54

       Uh, but you, we can see sexual violence, if men are able to procreate without having to do any investment, the ultimate form of that is to not even have to ask for consent as well.

    2. SSSteve Stewart-Williams1:47:11

       Yeah. Yeah. Indeed. And you know, it has been argued that the tendency in some men to do that, to take that path, does have evolutionary roots. Um, and, and I guess really you just have to have two things. You have to have men's greater interest in sexual variety and, and casual sex-

    3. CWChris Williamson1:47:31

       Mm

    4. SSSteve Stewart-Williams1:47:31

       ... uh, coupled with their willingness to use violence in certain, uh, you know, certain situations. So y- because men are more interested in casual sex, it's going to be not uncommon for a man to want to have sex with a woman who doesn't want to do so.

    5. CWChris Williamson1:47:45

       Yep.

    6. SSSteve Stewart-Williams1:47:46

       And because men are willing to use violence-

    7. CWChris Williamson1:47:48

       Mm-hmm

    8. SSSteve Stewart-Williams1:47:48

       ... uh, sometimes to get what they want.

    9. CWChris Williamson1:47:49

       Mm-hmm.

    10. SSSteve Stewart-Williams1:47:51

        Every now and then you are going to have that situation where those, those factors add up and the, the man is going to try to force the woman to have sex.

    11. CWChris Williamson1:47:58

        Mm.

    12. SSSteve Stewart-Williams1:47:58

        That's not just found in our species. Uh, males in, in many species try to coerce women, uh, females rather, in- into sex.

    13. CWChris Williamson1:48:06

        Yeah.

    14. SSSteve Stewart-Williams1:48:06

        It happens in our species. It's also been argued though that because, uh, preserving female choice is so important across the animal kingdom, including in our own species, so important to women, uh, that that helps explain why sexual coercion and rape is so upsetting to women. You know? It's not w- we haven't just been socialized for it to be upsetting to women. It's very, very deep in a female's nature to be upset by it because it compromises female choice.

    15. CWChris Williamson1:48:34

        Oh, that's interesting.

    16. SSSteve Stewart-Williams1:48:35

        Yeah.

    17. CWChris Williamson1:48:36

        That's inter- because y- not, not only, not only is it fucking heinous, but you know that because somebody, because this male committed that behavior, they've had to disregard the entire female-wide value that is supposed to be, uh, universally, uh, protected.

    18. SSSteve Stewart-Williams1:49:02

        Well, right. Well, I mean, she's evolved this tendency to be choosier-

    19. CWChris Williamson1:49:05

        Mm-hmm

    20. SSSteve Stewart-Williams1:49:05

        ... about her mates than men have, and she's got these mate choice criteria and, uh, that, that's because she can have fewer offspring, and therefore each offspring counts for more. So she's got to be, uh, wiser in every making decision that she makes. And this other male has come along and has just taken that away from her, taken that choice away from her. Uh-

    21. CWChris Williamson1:49:27

        Yeah

    22. SSSteve Stewart-Williams1:49:28

        ... has gone against th- th- she's evolved to be m- to be choosier and, and has-

    23. CWChris Williamson1:49:31

        I think this-

    24. SSSteve Stewart-Williams1:49:32

        ... gone against that

    25. CWChris Williamson1:49:33

        ... yeah, I, I think that the inability of men to fully understand what fear of sexual violence must feel like-

    26. SSSteve Stewart-Williams1:49:42

        Yeah

    27. CWChris Williamson1:49:44

        ... is one of the reasons why any guy who's seemingly sort of flippant or callous about any type of male-female aggression-

    28. SSSteve Stewart-Williams1:49:55

        Yeah

    29. CWChris Williamson1:49:55

        ... even non-sexual violence-

    30. SSSteve Stewart-Williams1:49:56

        Yeah, yeah
23. 1:52:11 – 1:58:59

    Are Women Naturally More Nurturing?

    1. CWChris Williamson1:52:11

       yeah, yeah. Okay, what about the differences in parenting?

    2. SSSteve Stewart-Williams1:52:13

       Differences in parenting, that's quite a controversial one, actually. Um, that's one of the ones that people like least. The aggression sex difference, no worries, but the parenting sex difference people aren't so keen on. And that, it refers to the fact that in every culture, again, where we have good data, women do more of the direct parenting, uh, than, than men do. Uh, and they invest more in, in the young. Uh, they do more parental care. Um, men in every culture do more than your average male chimpanzee or male walrus.

    3. CWChris Williamson1:52:42

       Right.

    4. SSSteve Stewart-Williams1:52:43

       But they, they do less than women in every single culture. And that doesn't seem to just be because men are forcing women to do it. There do, do seem to be average differences in terms of parental inclinations with women being more interested in doing it, uh, than men are on, on, on average. And yeah, I guess the reason that it's controversial is that there's a concern that people are saying, making up an excuse why you should do it. So, so, like, the guys are using it as an excuse. It's just, it's just natural that you should want to be changing the nappies and doing these things that coincidentally I would rather not have to do.

    5. CWChris Williamson1:53:16

       Mm.

    6. SSSteve Stewart-Williams1:53:17

       Um, so that, that I think is the concern. But in a way it's ironic. So the fact that people consider it to be kind of an insult to say that on average women are more interested in parenting than men, um, implies a negative valuation of parenting or doing more of the parenting because if it didn't imply a negative valuation of that, it would not be an insult to say that women on average do that more.

    7. CWChris Williamson1:53:40

       Indeed, this has been one of my most ... One of m- one of the best ideas I think I've come up with over the last couple of years, which was the, the soft signal of male expectations.

    8. SSSteve Stewart-Williams1:53:49

       Yeah, yeah, yeah. I think you mentioned that when, when we met the first time, right?

    9. CWChris Williamson1:53:52

       Yeah, yeah, yeah.

    10. SSSteve Stewart-Williams1:53:52

        The soft, the soft bigotry of male expectations-

    11. CWChris Williamson1:53:55

        The soft bigotry of male expectations

    12. SSSteve Stewart-Williams1:53:56

        ... it's like as if we treat the, the male standard, what- whatever men do, that's the standard of what, what is right, and if women do it less, that's a bad thing and we should make them more like males.

    13. CWChris Williamson1:54:04

        Mm-hmm.

    14. SSSteve Stewart-Williams1:54:05

        But not so much, not so much the reverse. Um, yeah, and it is very ironic 'cause it's-

    15. CWChris Williamson1:54:10

        It's a really misogynistic worldview

    16. SSSteve Stewart-Williams1:54:12

        ... it, it is really, isn't it? It is.

    17. CWChris Williamson1:54:13

        Yeah.

    18. SSSteve Stewart-Williams1:54:13

        It is. And so to, to ... If we're taking a negative valuation of, uh, of parenting, which is what we are implicitly doing if we say that it's an insult to say women are more parental-

    19. CWChris Williamson1:54:23

        Mm

    20. SSSteve Stewart-Williams1:54:24

        ... we're implicitly, uh ... And if it is actually true that women on average are more parental by nature-

    21. CWChris Williamson1:54:29

        Mm

    22. SSSteve Stewart-Williams1:54:29

        ... then we're taking a negative valuation of a f- more female typical trait, and that is really sexist.

    23. CWChris Williamson1:54:35

        Yeah, yeah. What's the kibbutz experiment?

    24. SSSteve Stewart-Williams1:54:38

        Uh, the kibbutz experiment, the ... So there, there are, um ... There, there were these kibbutzim that they had in, in, uh, Israel. So these were these communes, uh, like highly egalitarian, uh, communes where they wanted to get rid of all traditional kind of structures, including traditional male-female ways where, where the woman is expected to do all of the childcare and the guy is out, out in the public doing the public stuff, she's at home doing the private stuff. So what they did was they would, um ... They would get all the kids and they would house them in communal houses, and then they would have dedicated adults within the group who would be the primary, primarily in charge of looking after all the kids. So the kids weren't living under the, the roof of their biological parents. They didn't think ... You know, the idea was everyone should care for everyone rather than having this traditional, what they, they sort of saw as bourgeois, uh, approach where people are specifically interested in their own biological children. They wanted to get rid of that.

    25. CWChris Williamson1:55:38

        Right.

    26. SSSteve Stewart-Williams1:55:38

        Um, they tried it. They did manage to make it work for a while, but what happened was that just the parents hated it, basically. The parents hated not having their own kids living with them under their, under their roof, and they agitated and complained about it and, and eventually it broke down.

    27. CWChris Williamson1:55:54

        Right.

    28. SSSteve Stewart-Williams1:55:54

        And the interesting thing was that, um, although both parents hated it, most of the ... The, the mothers particularly hated it, and a lot of the agitation came from the mothers more than the fathers. And it's a great example, a great case study because we often hear that, um, that women are placed in the primary caregiver role by men, that men have kind of forced them into the, into that role. But here was a case where actually- Uh, the women in particular were rebelling against the male leaders-

    29. CWChris Williamson1:56:23

        Yeah

    30. SSSteve Stewart-Williams1:56:24

        ... to try to put themselves into that role instead. So, so it's a- another example of a very common phenomenon where you see certain behaviors and certain aspects of human nature that emerge and persist despite culture, uh, rather than because of culture. Culture's pushing in the opposite direction.
24. 1:58:59 – 2:03:30

    Who Gets More Jealous in Relationships?

    1. CWChris Williamson1:58:59

       Yeah.

    2. SSSteve Stewart-Williams1:58:59

       Yeah.

    3. CWChris Williamson1:58:59

       What about differences between men and women in sexual jealousy?

    4. SSSteve Stewart-Williams1:59:03

       Um, that's an interesting one. So both are prone to it, like I mentioned, but for the reasons that, uh, you mentioned already, um, men, men's jealousy is more focused than women's on sex. So a sexual infidelity ... Like, like if you ask men, which would upset you more? Uh, your partner who you love going off and sleeping with somebody else or just forming a close emotional bond with somebody else? Now, both of those are upsetting to most men, but men are more likely to say that the sex is more upsetting than just the bond. And pose the same question to women and, again, it's, both of them are upsetting to, to the vast majority of women, but they're more likely to say that the emotional bond, the sort of falling in love, maybe falling in love with the other person-

    5. CWChris Williamson1:59:50

       Mm

    6. SSSteve Stewart-Williams1:59:50

       ... um, that that's more upsetting than just sex per se.

    7. CWChris Williamson1:59:53

       Mm.

    8. SSSteve Stewart-Williams1:59:54

       It's interesting, right? And it comes out of the fact that, uh, men have this, this problem of paternity uncertainty. Like you say, no man in the history of the species has ever, um, no woman rather, hi- in the history of the species, ever given birth and thought, "Now, how do I know that this is my kid and not some other woman's kid?" Whereas w- you know, for most men, more than likely it is their own kid.

    9. CWChris Williamson2:00:15

       Mm.

    10. SSSteve Stewart-Williams2:00:15

        Um, but there is always some non-zero chance that actually it's not-

    11. CWChris Williamson2:00:19

        Yeah

    12. SSSteve Stewart-Williams2:00:19

        ... that it's the, uh, the good-looking next-door neighbor's kid instead. So yeah, that's why sex is a more important issue for men than women. Women are more likely to be left holding the baby, and that is not good for their fitness-

    13. CWChris Williamson2:00:30

        Yeah

    14. SSSteve Stewart-Williams2:00:31

        ... 'cause it's going to reduce the time before they can have another kid and, uh, just make things a lot more difficult for them. And so the, uh, it's obviously not great if their partner sort of sleeps with somebody else. It's not great. They'll be very, very upset about it. Very often it, it destroys the relationship.

    15. CWChris Williamson2:00:48

        Yeah.

    16. SSSteve Stewart-Williams2:00:49

        But it's even worse-

    17. CWChris Williamson2:00:50

        Yeah

    18. SSSteve Stewart-Williams2:00:50

        ... for most women if the partner gets, uh, emotionally involved with somebody else because then the, whether, whether they want the relationship to end or not, it's gonna end 'cause they're gonna leave, very likely going to leave and, uh, set up shop with the other woman.

    19. CWChris Williamson2:01:03

        I have an example that I heard about from a while ago that a, uh, a friend was on 23andMe or ancestry.com-

    20. SSSteve Stewart-Williams2:01:13

        Mm

    21. CWChris Williamson2:01:14

        ... and one day in their 30s got an email notification saying, "You've got a new half-sister."

    22. SSSteve Stewart-Williams2:01:20

        Right.

    23. CWChris Williamson2:01:21

        And he says, "How the fuck have I got a new half-sister?" What it turns out was that 32 years ago, the dad had had a one-night stand affair. That kid had never met the father, never been involved again.

    24. SSSteve Stewart-Williams2:01:35

        Right.

    25. CWChris Williamson2:01:35

        But three decades later, this situation unfolds and, uh ... Ob- obviously awful, awful to try and live through, but I would've been fascinated to have done a study to work out what happens to, what happens to sexual jealousy and intimacy jealousy-

    26. SSSteve Stewart-Williams2:01:56

        Mm

    27. CWChris Williamson2:01:56

        ... and the fear of, uh, resources, resource provisioning needing to be split-

    28. SSSteve Stewart-Williams2:02:01

        Yeah

    29. CWChris Williamson2:02:01

        ... when you've gone past all of those things because you have this, you know, three-decade, as- assuming that there's not been more infidelity, this three-decade example of someone committing to the family and raising the kids and doing the rest of this stuff, and also the person that would've been the dependent, uh, is no longer in need-

    30. SSSteve Stewart-Williams2:02:21

        It's really interesting
25. 2:03:30 – 2:13:25

    The Biggest Personality Differences Between Men and Women

    1. CWChris Williamson2:03:30

       What do we know about sex differences in personality?

    2. SSSteve Stewart-Williams2:03:33

       Uh, well, there are some and they're pretty consistent. They're not huge. Two of them are bigger, uh, bigger than the rest. Now if you're thinking about the big five personality traits, so, so the OCEAN acronym, right? So openness to experience, neuroticism, extraversion, agreeableness, uh, and, uh, conscientiousness. I got that in the wrong order. That wasn't OCEAN, but, but those were the [laughs] those are the five. So, um, the two sex differences that are largest and most consistent are the sex difference in neuroticism, which is proneness to negative emotions like depression and anxiety, plus emotional volanti- volatility, so ups and downs. Um, and that is about a medium effect size. So I, I guess it's usually estimated between about 0.2 and 0.5, um, uh, standard deviation between, between men and women. There's that one, and then the other consistent one is the sex difference in agreeableness. Uh, and women on average score higher. Again, it's not a massive difference, heaps of overlap, but, but again, it's 0.2 to 0.5. I would say it's, um, it's a medium, small to medium sex difference-

    3. CWChris Williamson2:04:37

       Mm

    4. SSSteve Stewart-Williams2:04:37

       ... uh, as well. There are some sex differences in the other, uh, three big five traits. Um, often, n- not always. You sometimes find that women score a bit higher in conscientiousness, but, but not always.

    5. CWChris Williamson2:04:51

       Mm.

    6. SSSteve Stewart-Williams2:04:51

       Some studies don't find that.

    7. CWChris Williamson2:04:53

       Okay.

    8. SSSteve Stewart-Williams2:04:53

       Uh, extraversion, on average women slightly higher on extraversion but, but again, not always and it's, it's a smaller difference if it is one.

    9. CWChris Williamson2:05:00

       Mm.

    10. SSSteve Stewart-Williams2:05:02

        Uh, and then, uh, uh, what's the other one? Conscientious [laughs]

    11. CWChris Williamson2:05:08

        Openness.

    12. SSSteve Stewart-Williams2:05:08

        Oh, openness. Yeah, openness, slightly higher for, for women as well or no difference.

    13. CWChris Williamson2:05:13

        What's the explanation for why those would be the case?

    14. SSSteve Stewart-Williams2:05:15

        Uh, well, I th- I, I don't think we know for sure, but my best guess, so the neu- neuroticism sex difference, so that's proneness to things like anxiety and depression, and I think women... Th- there's a general trend where women seem to be more self-protective than men, which is kind of the flip side of the fact that men take greater risks than women. They're more risk-taking. I think that that evolved because that is, um, about trying to propel yourself up the status hi- hierarchy. You've got to take risks in order to do so. Uh, and men have evolved to do that more than women because they have a higher maximum offspring number. But yeah, the flip side of, of risk-taking is to be more self, self-protective. Part of that is to be more prone to anxiety. Anxiety, the function of anxiety is to, it's the same as the function of the, of the turtle shell. It's to protect yourself. It's about protection. So I think that's why women are more neurotic. Now, the agreeableness sex difference, so women on average are more agreeable. Um, I don't have quite as strong an idea about that. I do think that... Well, I guess, I guess it could be the flip side of the fact that men are, um, sort of more, more aggressive, more, more pushy ab- and, and that evolved, like, like we've discussed to try to again get up the status hierarchy, uh, beat rival males to, to go up in the world and achieve status and resources. Uh, women have evolved to do less of that and one manifestation of that is the fact that they're more, more agreeable, more friendly, more compassionate. Um, and, and just the way that women have evolved to form social bonds, it does tend to, uh, have a higher level of compassion a- and, and understanding the other person. Um, that seems to be more common in, in women than men.

    15. CWChris Williamson2:06:54

        What about the people versus things divide?

    16. SSSteve Stewart-Williams2:06:56

        Mm. So that's an interesting one, right? Um, that is a bigger difference. That's actually quite a big difference. It's one of the bigger psychological sex differences and the effect size there is, is like one standard deviation or even, even a bit more when it comes to people, people versus things.

    17. CWChris Williamson2:07:12

        Right.

    18. SSSteve Stewart-Williams2:07:13

        Very, very consistent. I think there's a good case that it is not just due to socialization. So, so one thing is that, like I mentioned earlier, it has persisted for as long as we've been measuring it. Very, very consistent. Even when the culture's trying to push against it and, and get women more interested in things related to professions, traditionally male professions. Seems to be related, as we also mentioned, uh, seems to be related to prenatal hormonal exposure and one thing I haven't mentioned already is that it's also very, very cross-culturally consistent. So there was one study that had about 200,000 people in it and found that sex difference in career-related interests, found it in 53 out of 53 nations.

    19. CWChris Williamson2:07:52

        Mm.

    20. SSSteve Stewart-Williams2:07:52

        And another one had half a million people and found it in 80 out of 80 nations.

    21. CWChris Williamson2:07:56

        Wow.

    22. SSSteve Stewart-Williams2:07:56

        And that level is amazing, right? That level of cross-cultural uniform- uh, uniformity, you just hardly ever find it in the social sciences but you do find it for that difference.

    23. CWChris Williamson2:08:05

        And this has been around for 100 years?

    24. SSSteve Stewart-Williams2:08:07

        Yep. Yeah.

    25. CWChris Williamson2:08:08

        It was first documented in 1911?

    26. SSSteve Stewart-Williams2:08:09

        Yeah, yeah. That's right. Yeah. That's when they first, first documented it and it's been consistent ever since. It's one of the biggest differences and I always find that pretty interesting really because the kind of careers that we have today are evolutionarily novel. So you might not necessarily expect that to be one of the biggest sex differences.

    27. CWChris Williamson2:08:26

        Mm.

    28. SSSteve Stewart-Williams2:08:26

        You know, interest in careers that just haven't existed throughout the vast majority of evolutionary history for our species.

    29. CWChris Williamson2:08:32

        Yeah, yeah, yeah, yeah.

    30. SSSteve Stewart-Williams2:08:32

        But, but it's there and very consistent.
26. 2:13:25 – 2:16:55

    Are Cognitive Sex Differences Real?

    1. SSSteve Stewart-Williams2:13:25

       enough.

    2. CWChris Williamson2:13:25

       What about cognitive abilities? Is there a sex difference?

    3. SSSteve Stewart-Williams2:13:28

       Cognitive abilities, um, that's ... If anything is ... I, I would say that's probably the most controversial topic that I deal with in the book.

    4. CWChris Williamson2:13:37

       Sick. Let's bury it two hours into the episode.

    5. SSSteve Stewart-Williams2:13:38

       [laughs] Yeah. Um, so there are some. I guess a few things to say, uh, to avoid, try to avoid getting canceled is first of all, that there are, there are no sex differences in the cognitive ability that matters most to most people, which is IQ or general cognitive ability. Um, there is basically zero sex difference in the average there. Um, now people ... When, when you say that, some people will say, "But that's because IQ tests have deliberately been constructed to create equal averages." Um, and that is true.

    6. CWChris Williamson2:14:10

       Have they?

    7. SSSteve Stewart-Williams2:14:10

       Some of them have. Some of them have, but there are some IQ tests-

    8. CWChris Williamson2:14:13

       What? To, to offset the sex difference?

    9. SSSteve Stewart-Williams2:14:15

       Well, that, that's the, that's the theory, and so, so some of, some of them have been deli- deliberately str- um, created that way, but some haven't. But even those ones that haven't been created specifically to give the same-

    10. CWChris Williamson2:14:27

        Hmm

    11. SSSteve Stewart-Williams2:14:27

        ... the same outcome and balancing spatial versus verbal and that kind of thing, um, even when they haven't, they, they give Basically the, the same averages with representative samples of people. Now, sometimes you'll get, uh, some studies that will have males doing slightly better on average, but, uh, I'm persuaded by the argument that that is because the very low IQ males are more likely to fall off the map, fall through the cracks and kind of disappear and, and not end up in the samples-

    12. CWChris Williamson2:14:53

        Right

    13. SSSteve Stewart-Williams2:14:53

        ... than the low IQ women bringing down, bringing down the female average.

    14. CWChris Williamson2:14:58

        Because we do have a higher variance-

    15. SSSteve Stewart-Williams2:14:59

        Yeah

    16. CWChris Williamson2:15:00

        ... right?

    17. SSSteve Stewart-Williams2:15:00

        Yeah, yeah, yeah. There, in cognitive abilities, there's higher variance, yeah. Average is the same. The variance is slightly greater in men than in women. So-

    18. CWChris Williamson2:15:08

        More male geniuses and more male retards.

    19. SSSteve Stewart-Williams2:15:10

        That is exactly right, but, uh, important to, uh, note that that's quite a small effect. Um, and that is ... This is the controversial area and that's maybe the most controversial claim within that controversial area. [laughs] Um, so I always like to follow that up by saying, so that, that ... People hate that because it's a cognitive advantage that gives an advantage to guys, but there are also other cognitive, um, ability sex differences that give the advantage to women.

    20. CWChris Williamson2:15:36

        Yeah.

    21. SSSteve Stewart-Williams2:15:36

        So women on average, um, are better verbally. Um, that is one. And another one is that among the minority of people who are really, really gifted at maths, the women are more likely than, than the men to also be gifted verbally.

    22. CWChris Williamson2:15:50

        [laughs]

    23. SSSteve Stewart-Williams2:15:50

        So they're, they're more likely to be a double threat.

    24. CWChris Williamson2:15:53

        That's cool.

    25. SSSteve Stewart-Williams2:15:54

        Uh, so that's ... So no average ad- differences in IQ. Where you do find differences, they're just as likely to favor women as men. Some of them, s- in some cases, men are slightly better, s- spatial abilities, uh, that's an example.

    26. CWChris Williamson2:16:08

        Yeah.

    27. SSSteve Stewart-Williams2:16:09

        Verbal abilities though, women tend to be somewhat better. And then most of the differences are small. So the personalit- they're smaller than the personality differences. They're much smaller than the differences in interests.

    28. CWChris Williamson2:16:20

        Yeah.

    29. SSSteve Stewart-Williams2:16:20

        So when it comes to cognitive abilities, we're much more alike than different.

    30. CWChris Williamson2:16:24

        Mm.
27. 2:16:55 – 2:23:34

    Why Women Outlive Men

    1. CWChris Williamson2:16:55

       What about physical health?

    2. SSSteve Stewart-Williams2:16:57

       Physical health, um, there are some definite sex differences there. Uh, one of them, and the one that's probably best known, is that men are more prone to cardiovascular disease than women, more prone to heart attacks in particular. Um, at least among, you know, like, like in 50s and 60s. Until, till very old age, men are more prone, uh, to those. Women are more prone to immune system disorders. They're more prone as well to, to pain disorders. Uh, men are more prone to most forms of cancer other than sort of reproductive cancers that only strike one sex or the other. Uh, men are somewhat more prone to, to cancers as well.

    3. CWChris Williamson2:17:35

       Yeah.

    4. SSSteve Stewart-Williams2:17:35

       And actually one of the big ones is that men die younger on average than men in the vast majority of cultures, uh, including even most cultures where women have high rates of, of death during childbirth.

    5. CWChris Williamson2:17:46

       Mm. Mm.

    6. SSSteve Stewart-Williams2:17:48

       So we drew the, the short straw there.

    7. CWChris Williamson2:17:50

       Eunuchs in the Korean Joseon dynasty lived longer than intact males of identical social standing-

    8. SSSteve Stewart-Williams2:17:55

       Yeah

    9. CWChris Williamson2:17:55

       ... demonstrating that testosterone has a direct biological cost to male lifespan.

    10. SSSteve Stewart-Williams2:18:00

        That is very true. So I touch on that in the book. In A Billion, A Billion Years Of Sex Differences, I write about how actually, most people probably don't know this, but we do actually already have an intervention that we could in principle do which would completely obliterate the, the average difference in lifespan between men and women and would extend men's lifespan, and that is castration. It's got to be, um, castration before you hit puberty though.

    11. CWChris Williamson2:18:23

        Mm.

    12. SSSteve Stewart-Williams2:18:23

        So, you know, sadly enough if anyone wants to take that approach-

    13. CWChris Williamson2:18:26

        Mm

    14. SSSteve Stewart-Williams2:18:26

        ... if you've already hit puberty-

    15. CWChris Williamson2:18:27

        Yeah

    16. SSSteve Stewart-Williams2:18:27

        ... it's too late. Uh, but yeah, the fact that it, it would work is ... it's interesting. Does show that it's testosterone that is making us bigger, stronger, more aggressive, but also shortening our, our lifespan as well.

    17. CWChris Williamson2:18:38

        If male mortality rates were lowered to female rates, Randy Nesse who did the-

    18. SSSteve Stewart-Williams2:18:42

        Yeah

    19. CWChris Williamson2:18:42

        ... evolutionary medicine studies-

    20. SSSteve Stewart-Williams2:18:44

        Yeah

    21. CWChris Williamson2:18:44

        ... calculated we would save more years of life than if we cured cancer.

    22. SSSteve Stewart-Williams2:18:50

        It's well over-

    23. CWChris Williamson2:18:50

        If male mortality were at female rates, we would save more years of life than if we cured cancer.

    24. SSSteve Stewart-Williams2:18:55

        Yeah. So we're so used to it, so used to the fact that men die younger, that we don't really think about it I think. But then when you do think about it, yeah, you find that that is a, it's just a massive, massive difference.

    25. CWChris Williamson2:19:05

        And then we've got 88% of Darwin Award winners, which are people who die through spectacular self-inflicted stupidity are men.

    26. SSSteve Stewart-Williams2:19:12

        Yeah.

    27. CWChris Williamson2:19:12

        But 90% of Carnegie Hero awards, which are given to-

    28. SSSteve Stewart-Williams2:19:16

        Yeah

    29. CWChris Williamson2:19:16

        ... people who risk someone's life in order to save a stranger also go to men.

    30. SSSteve Stewart-Williams2:19:19

        Indeed.
28. 2:23:34 – 2:26:21

    Why Mental Health Differs Between the Sexes

    1. CWChris Williamson2:23:34

       Hmm. You touched on it earlier on. What about differences-

    2. SSSteve Stewart-Williams2:23:35

       Yeah

    3. CWChris Williamson2:23:35

       ... in mental health?

    4. SSSteve Stewart-Williams2:23:37

       Mental health, um, so there's the neuroticism sex difference first of all. Women are more prone to depression and anxiety, just sort of day-to-day depression and anxiety, um, rather than clinical levels of it. But at the extreme of that distribution, they are also more prone to clinical depression and clinical anxiety disorders.

    5. CWChris Williamson2:23:56

       Hmm.

    6. SSSteve Stewart-Williams2:23:58

       Uh, men are slightly more prone to schizophrenia. Men are much more prone to like antisocial personality disorder, sociopathy, psychopathy, uh, more likely to be psychopaths. Hmm, what else is there? I'll tell you one that we don't find a sex difference is bipolar disorder. That is... I say in the book that that's the, the least sexist disorder on record-

    7. CWChris Williamson2:24:20

       [laughs]

    8. SSSteve Stewart-Williams2:24:21

       ... uh, [laughs] because it's basically the same, uh... Ac- across cultures, it's about the same frequency in both sexes.

    9. CWChris Williamson2:24:26

       What's your explanation for why we would have these differences in mental health?

    10. SSSteve Stewart-Williams2:24:31

        Well, with the depression and anxiety, I think that's just a, um, side effect of the neuroticism sex difference. So at, at lower levels, it's adaptive for women to be, uh, girls as well-

    11. CWChris Williamson2:24:43

        Hmm

    12. SSSteve Stewart-Williams2:24:43

        ... but especially women to be somewhat more anxiety-prone because they, they protect themselves more and they're not taking risks, uh, in the way that is more adaptive for males-

    13. CWChris Williamson2:24:53

        Hmm

    14. SSSteve Stewart-Williams2:24:54

        ... um, because of the higher maximum offspring number. Um, I... So it's adaptive at that level, but I think that because you have a distribution, it, it means that inevitably some people are going to be the extreme of that distribution, and I don't think it's actually adaptive out there. So I don't accept adaptive explanations for clinical depression or clinical levels of a- anxiety disorders.

    15. CWChris Williamson2:25:15

        Hmm.

    16. SSSteve Stewart-Williams2:25:16

        I think that that is a sort of, uh, non-adaptive or actually maladaptive often byproduct of sex differ-

    17. CWChris Williamson2:25:22

        Like spandrel type thing?

    18. SSSteve Stewart-Williams2:25:23

        Kind of a spandrel, yeah. So just a side effect, um, exactly, of differences that closer to the mean are adaptive.

    19. CWChris Williamson2:25:30

        Hmm.

    20. SSSteve Stewart-Williams2:25:31

        The schizophrenia difference, I don't have a theory about what that is, and I don't think there is, that there is a theory yet about why that is more common among men than women.

    21. CWChris Williamson2:25:38

        Hmm.

    22. SSSteve Stewart-Williams2:25:39

        Uh, something I didn't mention, actually, autism is more common among boys than girls. Uh, ADHD is more common among, uh, boys than girls as well. Um, so yeah, ADHD, I think that, again, that's just a sort of offshoot of the fact that boys are kind of more active on average than girls and sort of less attentive and more likely to get distracted and run- running around the place. And it's not a problem at, in the usual... I mean, it might be irritating for parents and teachers, but it's not a big problem in the normal, uh, range. But at the extremes, it is a, quite a problem, and it's a problem more often suffered by males than females a- as an offshoot of the differences at the mean.

    23. CWChris Williamson2:26:20

        Hmm.

29. 2:26:21 – 2:29:53

    What Happens When We Deny Sex Differences?

    1. CWChris Williamson2:26:22

       After going through all of this, doing all of the, the research, obviously you've been deep in this for a long time-

    2. SSSteve Stewart-Williams2:26:26

       Yeah

    3. CWChris Williamson2:26:27

       ... and then doing the book, what happens or what's your fear when people don't respect sex differences or they deny them? What What's the sort of world that we live in-

    4. SSSteve Stewart-Williams2:26:38

       Yeah

    5. CWChris Williamson2:26:38

       ... if that happens?

    6. SSSteve Stewart-Williams2:26:39

       It's a good question, and I think it's a particularly good question because we're always focusing on the dangers of exaggerating sex differences-

    7. CWChris Williamson2:26:46

       Right

    8. SSSteve Stewart-Williams2:26:46

       ... and, and moralizing sex differences. And I think there are lots of problems with doing that, and we need to be careful not to do it. Um, but where I think I disagree with a lot of folks is that I, I think that there are also problems with doing the reverse, that there are also problems with minimizing sex differences and denying them. Um, so one thing is that just as, in exactly the same way that some people who exaggerate and moralize sex differences, they try to push people into traditional gender roles. People who deny the differences or, or like massively minimize them, they're in danger of trying to push people out of gender roles. So kind of replacing one gender straitjacket with, with another unisex gender strait-straitjacket or like a, maybe reversed, gender role reversed, uh, straitjacket. Um, and then we've actually touched on another of the big problems I think with minimizing the differences, which is the fact that trying to explain gender gaps in society, like occupational gender gaps-

    9. CWChris Williamson2:27:39

       Right

    10. SSSteve Stewart-Williams2:27:39

        ... there's, there's a whole host of problems with doing that, that, that we discussed. Um, uh, other problems, uh, with minimizing sex differences is that there are certain, uh, physical health problems and, and mental health problems, um, that ... So, so not only do the frequency of, of different problems differ between the sexes, sometimes the, um, symptoms differ as well. They, they present differently.

    11. CWChris Williamson2:28:05

        Right.

    12. SSSteve Stewart-Williams2:28:06

        So like cardiovascular problems present differently for women than men. Women are more likely than men to have shortness of breath as a, as a, uh, as a symptom rather than sort of shooting pains down the arms and the other kind of classic problems like that. And if you don't focus on sex differences, you might be more likely to overlook the symptoms of heart attacks in women.

    13. CWChris Williamson2:28:25

        Mm.

    14. SSSteve Stewart-Williams2:28:25

        Traditionally, doctors and people themselves have been, have overlooked it for that reason-

    15. CWChris Williamson2:28:29

        Mm

    16. SSSteve Stewart-Williams2:28:29

        ... because they've underestimated the sex differences.

    17. CWChris Williamson2:28:31

        Mm.

    18. SSSteve Stewart-Williams2:28:32

        Uh, mental health-wise, same deal. So even though autism is more common among boys than girls, there is a strong case that it's under-diagnosed in girls, and part of the reason for that is that it, it presents somewhat differently in girls. It's less likely, for instance, to involve repetitive behaviors, so people might not know. If they, if they're not aware of that sex difference, they might overlook it in girls, and that means girls won't get the help that they need.

    19. CWChris Williamson2:28:57

        Mm-hmm.

    20. SSSteve Stewart-Williams2:28:58

        Uh, and yeah, likewise with, um, social problems. Uh, if we're looking at social problems like intimate partner abuse, um, if we assume that all intimate partner abuse only goes in one direction, uh, s- like male to female-

    21. CWChris Williamson2:29:13

        Mm

    22. SSSteve Stewart-Williams2:29:13

        ... uh, then we're gonna like underestimate the extent of which it sometimes goes in the, in the other direction.

    23. CWChris Williamson2:29:19

        Mm-hmm.

    24. SSSteve Stewart-Williams2:29:20

        Um, yeah, there's a whole-

    25. CWChris Williamson2:29:20

        But the majority of it is bidirectional, right?

    26. SSSteve Stewart-Williams2:29:23

        Uh, at, at low levels it is, yeah.

    27. CWChris Williamson2:29:25

        Yes.

    28. SSSteve Stewart-Williams2:29:25

        Sort of low levels, um, verbal, uh, abuse, pushing and shoving. And actually, in, in the West there's even some data suggesting that, uh, uh, like verbal abuse might be more common women toward men.

Episode duration: 2:33:38