 Testosterone. What a great subject. Testosterone. It's the hormone that divides us. Now, this might, this might be a controversial statement today. It wasn't that long ago, but did you know that men and women are biologically different, and behaviorally different, and there's a biological root to all of this. Now, of course, there are societal pressure, pressures, and cultural pressures that make us behave a particular way, but there are biological ones as well. This is not contested in science, and in today's episode, we interviewed someone that talks all about this, wrote an amazing episode. You're gonna love this episode. By the way, here's our giveaway. I know that's why you're tuning in to watch the intro. You want to know what you can win for free? I get it. Here you go. Maps Aesthetic. That's what we're gonna give away for free in today's episode. Here's how you can win free access to Maps Aesthetic. Leave a comment below in the first 24 hours. Give us your thoughts on the episode. Make it a compelling comment. If we like your comment, we'll notify you, and then you get free access to Maps Aesthetic. By the way, you also have to subscribe to this channel and turn on your notifications. One more thing. We're running a 50% off sale promotion on two very popular programs. Maps Strong and Maps Power Lift, both half off. Go check them out, or go sign up at mapsfitnessproducts.com. Just use the code Augustspecial with no space for the discount. All right? Enjoy the show. So Carol, thanks for coming on. I'd like for you to give our audience a little bit of background to yourself. And then I'd like you to go into why you studied and wrote a book on testosterone of all things. Great. Okay. First of all, thank you so much for having me. It's a thrill to be here and meet all of you. As far as background, how far back do you want me to go? I can talk about not being the ideal student in high school. Maybe some of your listeners could relate to that. Yeah, sure. So I like to talk about where I came from because I think it's important for people to know that just because you weren't a stellar student early on, that doesn't mean that you can't change direction and kind of try to sort things out and get to where you're meant to be or where you have to work hard to go, but you can work hard and focus and change things. And so in high school, I was pretty crazy. Yes, I was definitely pretty crazy. So all my great high school friends who are helping me now on Facebook and stuff and supporting the book know exactly where I came from. And that is somebody who skipped so many classes that I didn't have a diploma in my folder when I graduated. And so I was not a star student like almost all of my Harvard students. So it feels weird to be there teaching them when I came from such a different place. I didn't know what I wanted to do. Eventually I did get into a great college, but it was a different college, Antioch College, which I loved. And then that's when I started to become curious about the ways that biology shapes our behavior. And so that just kind of planted the seed. And then it took 10 years for me just having a job and software and kind of trying to get my shit together and, you know, just have an apartment, have a job, just have a life. And I did a lot of traveling and reading. And that's how long it took me to figure out that I really wanted to go to graduate school and study the evolutionary basis of human behavior. And I didn't really have a super strong focus at that point. So I ended up, I read a couple of books. One is The Selfish Gene by Richard Dawkins about how genes and evolution motivate behavior. And then I read another one by somebody named Richard Rangham, which was about trying to, focused on trying to understand human aggression using an evolutionary perspective. And he had a field site in Uganda where he studied wild chimpanzees. So I read that book, quit my job and applied to Harvard to grad school because I wanted to work with him. And I got rejected because I had no relevant experience. But I had already quit my job. So I was like, you know, this is what I'm doing. I'm not giving up. And so after I got rejected, I went up to meet with him and a few other people in the department, which at the time was biological anthropology. And they, you know, said, you have to get experience. And so I was like, all right, give me, give me some experience. This is what I'm doing. How do I do, what can I do? So I just kept kind of pushing and I just really didn't give up on that goal. And ultimately Richard offered me a job getting some research experience and running the field site, the chimpanzee research field site in Uganda for a year. So that was thrilling. My friends and family were very nervous about it because this was a very tumultuous time in the region of Africa that I was in. There was a couple of civil wars going on. There were a lot of people being attacked with machetes and there was also like a huge number of rapes and murders. So it was a little bit tricky. But I went out there and got to watch chimps and, you know, learn about chimpanzee behavior and how to research it. And so that was what really got me interested in testosterone because if you are somebody, anybody who spent time with chimpanzees in the wild, notices right off the bat that there are massive sex differences that in a lot of ways parallel what we see in humans. So, you know, you've probably seen videos or maybe you've seen in person adult male chimpanzees sort of going on what look like rampages, you know, and like doing these threatening displays and beating up some females and definitely competing for status and beating up other males potentially. So there's a huge obsession with status. There's a lot more physical aggression than you would see in the females who really on average or just put on average before everything I would say are, you know, much more peaceful although they are capable of also being very physically aggressive. But I didn't see any really extreme female aggression at all, just some very, very low levels. But the males regularly, the adult males every day are doing something physically aggressive, getting into physical fights, you know, running around screaming and dragging big branches and, you know, even beating their chests and trying to threaten other males. They can also be really, you know, loving and nurturing and friendly too, but it's just the differences in the male and female behavior were so striking, you know, and the females are with their families and they tend to be very nurturing. So given there's no culture, human culture that is among wild animals, you know, the obvious explanation for the parallels between their sex differences and our sex differences is biology, is genes, and ultimately testosterone. So that's the most potent biological factor that can explain why the sexes behave so differently, especially when there's no human culture saying, okay, men. You have to be this way. Exactly. Were there assumptions that you went into when you started to watch these chimpanzees or did you go in completely open-minded? And if so, what were the craziest things that you noticed about them? Yeah, no, I had no... I was pretty, you know, I'd read a bunch of books, but I really didn't know a lot about sex differences or testosterone even. I wasn't really sure what it was or it's sort of embarrassing to say now, but or what it did. So I really had no preconceived notions. I just wanted to understand human behavior and where it came from and how we evolved and how our own biology shapes our behavior. Would you say this is safe to say that the differences in sexes and chimpanzees, although there are parallels between chimpanzees and humans, they're much more pronounced or extreme. Yes, and thank you for saying that because that's really, really important. They're definitely much more pronounced. Human males are nowhere near as violent as male chimpanzees. Like we can... One example that people sometimes use is, you know, I just took a plane from Boston and there were a bunch of strange adult human males together on the plane not beating the crap out of each other. Like that would never, never happen in chimps. You know, if you meet a chimp from a different community and you're an adult male, there's going to be a fight. That's just not tolerated. There's high levels of physical aggression in the way we don't see it humans. And one thing we have to keep in mind is that humans are weird mammals obviously because of our culture but also because you guys, I don't know if any of you have kids. Oh, we're all fathers. Okay, so that's great. So you know that you are probably, you can feel yourself capable of extreme aggression, particularly if someone messes with your mate or your child. Absolutely. But on the flip side of that is you're capable of probably... I'm going to start crying. Yeah, that's all right. A level of... Because it's so beautiful to see. It was beautiful to see in my husband. A level of nurturing that you never expected. And what's amazing is that that kicks in when you're exposed to your, the stimulus that, or the stimuli that are your offspring that kicks in just like it does in male birds. Now, do you think that's naturally or do you think that's kind of been nurtured into us over? Totally natural. It's totally... I think that that is natural. I don't see the evidence that anyone's telling you to be aggressive or to be... I mean, certainly there are social pressures but you feel that from so deep down in you and it's coming out because you have a child and you're going to increase your reproductive success if you're nurturing and bonded and protected and protecting your offspring and your partner. Yes. And no other man can come near your partner. So you probably... I mean, sexually obviously. So sorry, even plant that seed in your head right now. But so you probably feel at the same time, physically protective but also incredibly nurturing and responsible for the safety and well-being. Yeah, would this also be... So chimps don't have that. So I just want to just sorry, complete that circle is that chimps don't have that. Most mammals, 95% of mammals, the males have nothing to do with their kids. It's all about status and sex, basically, finding males. I was just going to say... So that amps up the male-male competition. I was just going to say because this is... I love... This is a topic I'm so into. Obviously, nowhere near your expertise at all. Oh, I'm sure. I think you probably are. But I do love this. You're the dad. I read a lot about this and human males are remarkably paternal in comparison to all other mammals or males where the males often will kill their young if they don't look like them or extremely aggressive. We're pretty damn good as a parent in comparison to others. But there is a difference, right? There is still a general difference between men and women in that. So this study of chimpanzees really sparked your interest in of all things, of all drivers, testosterone. Now, why was it testosterone? Why not estrogen or other drivers? Yeah, I mean, to be honest, and yeah, to be honest, it's because the... I loved being with the females partly because it was just so beautiful to sort of the peacefulness and the nurturing and it's quiet. You can just hear the birds and the insects and she'd just be there and the little, you know, they're so cute, the little chimp babies and juveniles are just adorable. And you can just sit there in the jungle and watch them play and twist around on the branches and cuddle with their moms and that's wonderful. However, when you're with the males, it's just a whole different ballgame and it's really exciting. And I liked watching the males because you never knew what was going to happen and it was going to be exciting and kind of like, oh my God, you know, there's so much activity and screaming and beatings and sex and that's testosterone. So yes, there are some incredible, mostly women primatologists who focus on females and estrogen. That's just not what I was drawn to. I grew up with three brothers, three older brothers. I was a pretty... I think I am and I was kind of on the masculine side as a kid, like I played baseball. I, you know, was just really more boyish in some ways and I don't know, I think I just also, you know, just my sort of experiences in high school and college and sort of having some bad interactions with men, you know, like staying all night out all night at parties and stuff, just was stupid from a lot of points of view. I think just got me as a woman, like I get females, right, in a way that I didn't get men and I think that I just was driven to understand that. So that is what drew me to testosterone. Okay, so here's a question I've been wanting to ask you because I heard you on Joe Rogan, this is why we called because I thought it was so fascinating what you wrote about and I did read a lot of your book and here's something that's very interesting and I want to ask you about. So when we're in utero, we're essentially, we look the same until our genes tell us to get this injection of testosterone and then there's this dramatic change in the fetus. But before that, I mean, they're almost identical. Unless you go and see, look at their chromosomes, you can't tell the difference but then testosterone comes in and we get this huge influx of testosterone and it changes the fetus into this, into a male from your standpoint, from what you've read, what are the evolutionary, I guess drivers or advantages? Like why does this even exist? Why have this hormone that changes our behaviors so much? What are the advantages to it? And what were the advantages and do these advantages still exist? Do we still need them? Okay, you're going to have to remind me all the different questions there because I want to get to all of them. So I want to start out with what happens in utero and us basically being the same. So the male and female thing is determined when, if there is a first obviously, most people already know this, but if there is a Y chromosome, almost always there are exceptions to this. So the chroma, I just want to say also that the chromosomes themselves do not define sex. So people get confused. They think that XX equals female and XY equals male. That's not always true and that's definitely generally true in mammals, but certainly that's not the case in other taxa like birds or amphibians. There's different chromosomal arrangements. So the second thing is, it is the action of the SRY gene, the sex determining region of the Y chromosome, which is a specific gene that produces a protein. And that protein is what's called the transcription factor. So that protein in the cells, there's an undifferentiated gonad up until about six weeks. So it could become an ovary, it could become ovaries or it could become testicles. So if that gene is present, it produces this protein, SRY, and that protein goes around to all the different chromosomes basically and up regulates other genes that produce other proteins that cause the cells in those undifferentiated gonads to go in the testicle direction. Got it. So you can have the Y chromosome, but if that gene isn't working or any of the important downstream genes that need to be up-regulated aren't working, there's one called like SOX-9 that it up-regulates on chromosome 17. So say there's a mutation in SOX-9 on chromosome 17. Then even if you have SRY, even if you have the Y chromosome and SRY, you still won't get testes. You will get ovaries because ovaries, the undifferentiated gonads go in the ovaries direction in the absence of SRY. Interesting. So they have to be told to become testicles. That's right. Otherwise they remain or that's the default ovaries. That is correct. Okay. So that is why some people say female is the default. In a sense, that's true. It's not quite that simple. Of course, there are other genes that have to be expressed, but they're going to be expressed in the absence of SRY. Got it. So that is the first way that we differentiate is not by testosterone, actually. It's by the action of this SRY gene. But then, once, you know, after six weeks, once the gonads differentiate into testes. So real quick, within the absence of testosterone, let's say the genes get differentiated. You get this protein that signals become testicles, but no testosterone later on comes into the body. You still get testicles. Yes. Okay. Oh, interesting. Yes, so that is what happens essentially in the case of complete androgen and sensitivity syndrome. Interesting. You get your X, Y, you have testes, everything's going fine, but your androgen receptor has a mutation. The gene that codes for the androgen receptor has a mutation. If it has a disabling mutation, your testes produce testosterone, but it can't be heard by the body at all. So you have a completely female phenotype. Interesting. 100% female. I mean, you don't have all of the internal reproductive organs. There's no uterus, but there's a, you know, totally normal vagina, that is what's called the blind vagina that doesn't connect to. Interesting. A uterus, but yeah, so you can have testes, but without testosterone, you do not develop a male phenotype in terms of the internal and external genitalia, in terms of secondary sex characteristics and in terms of brain masculinization. So once you get the testes, then a couple weeks later, those cells, specifically the latex cells start cranking out testosterone, and that is what then, it's also a transcription factor. So it also goes around to other chromosomes and regulates other genes that cause the development of apenis and of the vas deferens and starts to masculinize the brain. Now what is that? So you're talking about masculinizing the brain. I saw an article recently that made its rounds that said, essentially male and female brains are the same. It's funny because you dive in a little deeper into the study and they really kind of cut out differences and said those don't, you know, those really aren't big differences, although from my, from what I understand, if you took two brains and you took two very, you know, smart biologists, they could probably tell you if one was male or one was female. What do you mean by masculinizing the brain? What changes in the brain that makes it male? So I wouldn't say so clearly that testosterone makes it male. I think the male level of testosterone will generally, will masculinize the brain in ways that are detectable in behavior and that, yes, an expert, a computer program from what I understand would be able to differentiate male and female brains with something like 80 to 90% accuracy. So, because the issue is that there are lots of differences, but they are, they're widespread and they're a high number of them, but they're not as pronounced as they are non-human animals. Where an expert could just go, that's a male and that's a female. So you have to add them all up cumulative? That's right. Like a face. You're talking to the function of the brain versus not just like the physical. Yes. So it's, yes. I mean, so what testosterone, what we know from non-human animals and there's indirect evidence in humans that this is also the case is that testosterone acts in the brain to change the populations of neurons in different parts of the brain. It definitely in non-human animals and apparently in humans acts on an area in the hypothalamus which is called the sexually dimorphic nucleus of the hypothalamus and that area, testosterone causes that area of the hypothalamus to enlarge or actually prevents the death of neuron populations in that part of the brain. Oh, interesting. So the female brain prunes it whereas the male brain, the masculinized brain. I'm not 100% sure if that's due to increased growth or due to pruning, but one of testosterone's most pronounced actions is to prevent apoptosis or cell death of neurons in certain parts of the brain. What do we know that part of the brain, what do we know in terms of... Sex. So, okay. Sex. So like sexual identification? No. Well, that's interesting because they don't, so sexual identification in non-human animals isn't really a thing except for a couple of species, except for like sheep. You know, they're some gay sheep, but otherwise there's, as far as I know, there aren't any instances of exclusively gay animals. There's lots of homosexual behavior like I saw in chimps all the time. They would be basically blowing each other or sorry, can I say that? You can say whatever you want to. We're going to pop that video up real quick. No problem. You know, bonobos are like tons of homosexual behavior. Chimps have, you know, male bonding will frequently involve sexual behavior. So, but that doesn't mean that they're homosexual. You know, humans have these categories which is interesting and I think a lot of that does have to do with culture, the exclusive homosexuality. But anyway, that, so testosterone increases the size somehow of this sexually dimorphic nucleus of the pre-optic area, the SDN POA. And in order for the male to express male typical sexual behavior, so in a rat that's mounting. And what's cool is you have this, you know, extreme differences in sexual behavior, not like you do in humans where we can, you know, men and women can do a bunch of different crazy things. But in rats, the male, you know, pursues and mounts the female and the female has to stand still and basically stick her butt, like arch her back and stick her butt up in the air, that's lordosis. So estrogen, so no testosterone in her brain in utero, plus estrogen in adulthood activates that behavior in the presence of a sexually interested adult male and he will only engage in mounting behavior if he had high testosterone in utero, if his sexually dimorphic nucleus of the pre-optic area is big and if he gets testosterone in adulthood. Interesting. So that's the organizational, activation framework which apparently also applies to human males. You need at both times, you need it in utero and in adulthood to have male typical reproductive behavior. You brought up apoptosis and like cell protective, sort of like that being more of a focus in the male brain. Like do you think that's more, you know, geared towards like the risky behavior part of that with males, you know, as far as like a mechanism for survival? Yeah. Yeah. So the masculinization of the brain in utero does seem to be associated. It's definitely associated in non-human animals with aggression and rough-and-tumble-plan little kids and juvenile animals. So lots of juvenile animals, the males have much more physical play than the females, just like we see in humans. Like everyone knows that happens in humans, but a lot of people try to argue that this happens in humans because of like the patriarchy or socialization. Right. That's just not the case. There's just way too much evidence and I can be happy to talk about any of that evidence, but it is testosterone exposure in non-human animals that causes them to in the right environment, you know, have these high levels of rough-and-tumble play because they have to practice to compete for mates physically as adults because that's how evolution shapes them and we have evidence from humans. So first of all, we have the sex difference where, you know, males are exposed to high levels of testosterone and they have much higher rates of rough-and-tumble play and obviously physical aggression and adulthood. But also we have cases where girls, so female fetuses are exposed to unusually high levels of testosterone in utero and they have higher rates than average of rough-and-tumble play and they're more likely to want to play with boys and more likely to want to play with boys' toys. So we know, and they're more likely to be lesbians too. So we can see those effects in girls and part of the reason is that females are super sensitive to increases in testosterone whereas if you have males with the same disorder which is called congenital adrenal hyperplasia there's really no effect on behavior because males already have so much that when you add more to that and this is true in adults too except for muscle development as you guys probably know when you add more it doesn't really have a big effect if any on like libido or aggression but if you do that to females you're gonna see changes. Wow, very interesting. You know, you mentioned the culture aspect of it and in my opinion I think, I think obviously culture plays a role in how we act and how we think we're supposed to behave but I do think culture follows biology. In other words, the roots of it, the roots of us believing that boys like rough-and-tumble and like to jump off things in girls, and of course this is general, there's always exceptions. I think the roots of it are in biology so we observe this through thousands of years and then we develop culture around it. How do you feel about it? Well then we try to deny that. Sorry, what? And I was gonna say that a lot of times like, I see now too that in culture we're trying to deny the fact that we are animals at the end of the day and then culture has then, we've been trying to kind of move forward in this other direction. Isn't there a big movement right now of like not sexualizing your kid at all and not giving him specific toys in a certain amount of time, so like the colors, avoiding that. I have to just, I wanna come back to all of this. First of all, you guys, I'm totally serious. You're so impressive, it's even making me like what's happening to me. No, what you just said is such a, I think it's such an important point and it's kind of a nuanced point and a lot of people just assume that culture and patriarchy and the things that we teach boys, it's just obvious, which is true, that yeah, we do, if you think a baby is a boy baby, you're gonna be rougher with him or it, even if it's a girl, if you think it's a boy, you're gonna treat it differently. But the fact is, these sex differences are this way everywhere in the world. These natures are different everywhere. And so you're answering the question of like, well, that would be weird if every single culture had the same kinds of standards and the same norms and the same expectations. Of course it's coming from the bottom up and we're responding to it and shaping it and nudging it and there's different cultural norms that definitely do shape how people are able to express their natures or allowed to express their natures, right? But yeah, I think that's such, I think it is a sophisticated and important point that needs to be acknowledged. It's the same everywhere. It's just, and it's consistent with non-human animals. So I like to play this game, I don't want to take us off track, but I like to play this game of, this is from evolution. I do this with my wife all the time and noise the hell out of her. She's very intellectual and so we get to do this and we have fun and so here's a great example, right? And this is a common stereotype, although I, every guy I know- You're gonna give her the hunting and gathering. Oh yeah, like, I'll go, I'll be like, honey, where are the pickles? And she'd be like, it's in the fridge and I'll open the fridge and I seriously don't see it. I'm like, they're not here, where are they? They're right there. No, they're not. She'll walk over to the fridge, move four things and it's right there. Yes. And I'm like- I can relate to that a hundred. I know where everything is in the house. And I'm like, why didn't I move- And I work, I have a full-time job. I work my ass up. I'm just as busy as my husband. Why doesn't he know where anything is? And so I'm like, why didn't I just move, it happens all the time. And I thought, so here's my, here's my explanation. And I made this up, by the way, there's no evidence to support this. But I said, you know what, honey? It's because men evolved as hunters and when you're out in the wild, you don't want to disturb the environment. So you just look, you just look and you don't see it, it's not there. Yeah. And I said, women were gathering. And you move things around looking for very rare of colors. No, no. That was my tongue and cheek explanation. There is evidence, actually. Oh, really? So, yes. Yes. So first of all, here's one area where we can't compare humans to non-human animals because we have this intense sexual division of labor. Chips do actually have, do hunt. And I got to see a few hunts and that was amazing. They hunt monkeys and then they rip them to shreds and eat their insides. Wow. Yeah. So that's really cool. It's intense. It is intense. And they have first priority for the meat to eat the meat and then they can give it to whoever they want. But anyway, so for my dissertation, which I did at Harvard and I was in biological anthropology and cognitive neuropsychology at the time. So I was kind of bridging disciplines, but I looked at sex differences in cognition and how they relate to testosterone and the biggest sex difference is something called mental rotation. So that's the biggest sex difference in cognitive ability. So most people have no idea what it is. I had no idea what it was. I was like, this is totally boring. I don't want to do it. Who cares? However, I was trying to, can I just tell this little... Do it. I'm everyone's intrigued. No, so this, okay. So for my graduate work, you kind of have to, as a graduate student, sometimes try different things and see what sticks or where you're going to get results or what you really like or what's feasible to do or whatever. So I wanted to see, there was some evidence that one could manipulate testosterone levels through pornography. And so I had read one paper I have since learned that one paper just isn't good enough. You need like a lot of work that's replicated and there's where you have a robust finding. But so I saw one paper showing that men's testosterone levels went up when they viewed pornography. And now I can't even remember. Okay. So I was going to try to get local men baseball fans to come in. Sorry. I had so many different projects and now I'm getting confused. Forget about the baseball thing is a different story. So I had local men come in. I was just going to manipulate their testosterone and then test them in some different cognitive tests. And my advisor- Manipulate through pornography. Through pornography to get it to go up and dental surgery videos to get it to go down. Wow. So I was like- What a tough decision. It's going to be much more. A little bit. And then they're going to miss them. No, they didn't know what they were going to be getting. So they came twice and it was counterbalanced. So some men would come the first time and they got dental surgery and they didn't know that they were going to get pornography the second time. And then the guys who got porn the first time would get dental surgery the second time. Now I can't even remember why I'm telling you the story. There was- That's okay with the fact that you're here. I have something I want to ask you about this because we've actually discussed this. It's the hunting and gathering and the fridge thing. Okay. So this is- I'm going to connect. So but what is funny about it is I had to- There's something called the internal review board, the IRB. You can't do human subjects research at a university unless you clear it with the IRB. And you know, so this woman, I won't say her name. She was the head of the IRB. I had to go to her office and watch the pornography with her and it was lesbian porn that I was showing. Wow. That I was showing the guys because- It's a bonding experience. Yeah. No, it was bizarre and as you can like imagine- Sure. I'm picturing it. We were very different. Like she was, you know, a dean type and I was made and much younger and it was just weird. And yeah, we didn't include men. I didn't want to have pornography that had men in it because I didn't want the men to feel to have any competitive response to it at all. Oh, that's a good point. So what you're referring to is that there are studies that show that when men feel sexually competitive to another man, you can reliably see testosterone levels rise. It can happen, yeah. But anyway, it didn't work. It just doesn't work. And now I've since read other studies, it just doesn't happen. Testosterone does not go up while in sexual contexts unless it's competitive. Unless there's like a an attractive woman and you're trying to show off or you're competing with another guy in some way or whatever. Then James Roney has done this research. But the point is, so I learned a lot about mental rotation and I learned that I just had to throw in the pornography thing because I think it's not funny. I'm glad you actually went there though because we've actually theorized the opposite is true. So I told you before we got on air that one of the first conversations we had was the decline in testosterone in young men. Right, right. And one of the things that we theorized as a possibility was pornography. is watching too much pornography or just having too much access to it. Oh, that you don't have to work for it. You don't have to compete for it. So you don't need the testosterone. And also that it's just normalized. That is fascinating. Yeah, that was a theory that we have. No, I think that's interesting. I mean, of course there's the theory about phthalates, phthalates. Oh, yeah, yeah. There's a lot of reasons why people think testosterone levels are declining. No, but that's interesting. Yeah, that was what we actually listed a bunch. And just using apps. Yeah. You're also using apps instead of real life. Yeah, absolutely. And just think about the amount of it that you're getting. What we were talking about. We're all 40, right? So we were talking about, man, when we were a 17-year-old boy, you got the JCPenney Center catalog was all you got. You know what I'm saying? And you had a high deal. And you got to take it to the B. You got to look at it once a month if you were lucky, you know? Or maybe if your parents worked a lot, maybe a couple of times a week. But boys now have access on their phone to just a plethora of this. I have a 12-year-old boy. So I'm very sensitive to what he will be encountering. That was one of the theories that we thought contributed to. But I want to make sure I say about the sexual divisive labor and the evolution thing. Yes. So this thing, mental rotation is a skill where you can imagine objects. Like if I hold this up, you could imagine what these, if I held it to the side and I turned it around. You could imagine what these letters maybe look like from the, if they were upside down, or what this bottle would look like upside down when you envision it and you rotate it through your mind. Instead of just regenerating the image, like upside down, you actually rotate it. Anyway, the test involves more complex objects than this. Men really blow away women consistently everywhere on the list. Wow, really? This is a test you can take online. They'll show you shapes and then they'll have like options. What does this shape look like from another angle? From like, if you were to twist it, you know, move it 180 degrees. Yes, and men do that significantly better than women. Now here's a test. Yes, and it's so robust. It's a large, it is the largest sex difference in cognition. So what is the, What's hunting? Okay, so the, so the one hypothesis is that it is hunting, which I am skeptical about because, so I just want to get back to the hunting thing, because it's fascinating, because what you said is right on. So when you're driving, say, you're going to, when you give, when men give directions, they're more likely to say, go east, south, north, west on this, this, and that street. Women are more likely to say, turn left at the church, and then you'll see a big tree with blah, blah, blah, and there you're going to take a right. So there's like a dead reckoning that men tend to use to get from A to B also. So if you're hunting, you are really not, you have to have a sense. Pay attention to all other stuff. You're following your prey, right? So you have to have a sense of, where you are geographically and you have to be able to recognize the environment from a completely different perspective because it's not the environment that you saw when you were going out. You're going to see something different when you come back, say. So here's one I wanted to ask you about, since we're on this topic. I read that there's this test that they can run where they'll show just pictures of eyes. So just people's eyes and women are able to much more accurately tell you what that person's facial expression is. Happy, sad, afraid, terrified, whatever. And men tend to fail that much more often. Is that true? That is true. Okay. Now I would assume that the evolutionary roots of that would be because women were the society builders, right? They were the ones building the connections back at the tribe. And so they really had to understand, had to read each other very well, whereas the man not so much because we're out hunting. Would that be the... Yeah. I think it has to do with nurturing and family and the need to be sensitive to emotional states, probably in can or something. Yeah. I would think nurturing is something, that would be the main thing, like being able to read a baby's face if they're happy, they're sad. Yeah. Just really tuned into relationships, you know, human relationships. But I mean, but obviously male, the need for men to bond and understand each other and the enemy say in war, which is not just a human trait, you know, that's also really intense. So men have a whole other set, I think of mechanisms to, you know, work out status, for instance, in a way that females cannot. We have a lot of trouble working out conflict. Men get in a fight, it's resolved, status tends to be resolved, and then there's harm, it tends to be harmony until it's not anymore, until somebody challenges it. But that facilitates a bonding very quickly and intensely. And so I think there's something there that you have to read threat. Like you have to be able to be, and then are better at responding to threat and being attuned to signals of threat. Wow, that is so weird because if I go to a bar, I'm at a restaurant, I can tell like, we better leave, this doesn't feel safe. Whereas my wife will go into a room and then we'll hang out with people and we'll leave and be like, ah, did you see how she was, or did you see what he was doing? He was giving so much attitude to him like he was, I didn't notice any of that. And it's, what's interesting about these conversations, I do wanna say this, I wanna preface this that at the end of the day, we're all individuals, right? So there's always- Yes, it's all on average. Every, all these differences are on average. Yes, however, and I hate the fact that we run away from this topic so much because we're so afraid to, you know, fall into those, or encourage gender norms or stereotypes. Stereotypes, yeah. But for me, it actually helps with understanding because anybody who's married for a long time knows that oftentimes you just don't understand each other and understanding this kind of stuff helps, really helps me a lot because we kind of get each other a little bit better because, you know, she'll say, well, okay, he's a man. He's not gonna quite get this the way I do. Or vice versa, I may say, well, she might not feel the same way as I do because she's a female. She brings in another perspective. It does. It just adds more richness to our understanding. Yeah. So I wanna say two things. So one is just to finish up the hunting and gathering thing. And that is that, yes, women have better, so men have better mental rotation, better navigation skills. And women have better object location memory. But the size of the sex difference in object location memory is not as large as the male advantage in, say, mental rotation. But, yeah, so it's funny because in my house, the men seem to be losing things. And for whatever reason, I'll just know exactly where it is, probably because I'm the one who's doing more of the cleaning and putting things away, et cetera. But the second thing is, and this is something that I have talked about before, but it is very important to me and it is what you just said, which is that the insights that you can glean from understanding the forces that shape us, whether they're environmental, biological, obviously it's both, right? So that we express our genes in the context of a given environment. And so that shapes how we express ourselves. But understanding those forces, for me, I was just personally really important, partly because I, and this is weird because I've been teaching about hormones for a long time, but until I wrote the book, I hadn't sort of made the connection between my nudging and pushing my British relatively un-expressive, relatively to me, which isn't hard to be un-emotional, relative to me, pushing him to express himself more and to figure out what his problem is, like why isn't he able to access his emotions and tell me about how he's feeling. And I let up on that after writing the book, during writing the book, because one of the things is because I studied transgender, the literary on transgender people who changed their testosterone levels, reviewed some of them for the book, and I also got into this literature. And one of the things is that when you take testosterone, if you go from female to male levels, like from my level to your level, you do, on average, tend to become less emotional. Crying basically evaporates for many people. Oh, I have firsthand experience. So the point is that I then learn to accept him more and stop bugging him. That's just who he is. And it helped our marriage. And it's really, really improved that I just had an explanation that helped me to just accept that we're different. He doesn't need to be more like me. Sorry, I didn't mean... No, I was just adding to what you were saying, that I have firsthand experience of that being a bodybuilder who took copious amounts of testosterone to become this pro-bodybuilder and then to go off of it and then just have it crash. You went off it entirely. Yes. And you were missing your own because you'd shot your balls out basically. Yes. And so I went through this huge emotional roller coaster. That was one of the craziest things I ever felt. I mean, I even battled a little depression over it. I was crying over commercials. Like, it was a wild ride. Can you say more about what that was like? Like, did that give you an insight into what it's like to be a woman? No. Yeah, absolutely. I mean, as silly as that may sound, up until that point in my life, never has a movie and definitely not a like dog food commercial made me get emotional. You know, and I felt myself holding back tears and I'd be by myself sometimes going like, this is weird. This feels really different. Like to feel that way. But did it feel good or scary or overwhelming or like freeing? I'll tell you some of the things I liked. I was much more empathetic with my wife. I think her and I, I was just, I felt calmer. I felt, I mean, there's definitely, there's definitely a huge difference that you feel when you go through something like that where your hormone levels drastically change. I imagine people that go through things like menopause and stuff have similar type of feelings of a roller coaster on that. So I felt inconsistent for me. I felt way more mellow. I lost a lot of aggression. So the drive to lift heavy weights and to push like that. What about sex? Um, yeah, sex was plummeted because, yeah, no, it absolutely, and that was actually the main driver to get me back into using a therapy dose was because then it started to affect our relationship because then she thought I wasn't attracted to her because I wasn't chasing her like I used to chase her all the time. It was, I then was the one that was kind of more reserved with that. She had to have to come after me. And then she felt insecure like I wasn't, I didn't find her beautiful anymore. So that was amazing. This is all hormones. What's amazing is everything you're talking about is so important to our lives is all about hormones. It's just differences in hormones that have such profound effects. And we don't notice it in men because you guys are just, you know, have high T all the time. It doesn't fluctuate, right? It's not like in Seasonal Breeders, you know, which I talk about in the book where you can see the changes like, you know, with the deer growing antlers and getting aggressive and having sperm and high testosterone to outside of breeding season, you know, living peacefully with other males, not having weapons on their heads, et cetera. So because you can see it, and you guys, you can't see it, but you got the chance to experience it. Yeah, it was an awful experience to be honest. I mean, it was enlightening. It was enlightening because it made me more in touch with maybe more of her emotional side and empathy that she carried and calmer and less aggression. So at that side of it, I think I appreciated, but it did it. I lost a lot of drive, sex drive, drive. And just drive in general? In general. So that's fascinating. Yeah, and that's what caused the, I think the depression was, I lost the drive in general, the drive to be more successful. And I didn't go from like a guy who cared about being successful and lifting weights to absolutely nothing, but I could feel a significant difference. It became less of a priority or a thing I thought about. You know, Carol, speaking of drive, I remember reading this article a while ago that really made a lot of sense to me in the sense of why, because even now today, if you look at the craziest risk-taking behavior, anything, sports, jobs, whatever, they tend to be dominated by men. If there's somebody that's going to jump a bike over flaming cars and do a backflip, it's usually a guy that's going to end up doing this and risking his life, right? A young guy, yeah. So it's just crazy and then ambition. I mean, there are definitely women who do that stuff too, right? But it's on average. You're right. We're individuals. You're absolutely right. But there's generally speaking, you know, and risk-taking behavior in general, like men's car insurance is more expensive because we tend to speed more often. And getting more accidents are more likely to die in car accidents. Right. And so I read this article and it made perfect sense to me in this art. I remember what the number was, but it said something like, a society could lose something like 60 or 70% of its men and still survive. Whereas if a society lost, I think it was like 30% of its females or 20%, it would have trouble thriving because of course one man can impregnate X amount of women. You better be a good one if you're not going to have that. Right. And where women can only have one baby essentially in nine months. Right. And I'm like, maybe that's where the risk-taking comes from is that we're more expendable. Like, we should take the risk because if we die. We don't do well in a sausage fest. If you go and die, then it's not as big of a deal, but if a bunch of women die, holy cow, that could be a big issue. Well, yeah. No, I think that's correct basically that women need to have a long life and be healthy to maximize their reproductive success. So that's what we're all designed to do. Estrogen helps her do that. Gives her more body fat. She doesn't have the testosterone converting, you know, energy into muscle. She's taking in energy and converting much more of it into fat. So we're designed to convert energy into offspring. Right. So for men, yeah, risk-taking can pay off with higher reproductive success in a way that it does not for females. Females are competitive and can be aggressive, but it tends to be not in a way that puts their physical health at risk. So we can be extremely, as you probably know, nasty to each other in a way that men tend not to be. It's an indirect kind of mean girl type of aggression, but it's low physical risk. And men have a different type of aggression and that risk-taking, yeah, is gonna play out on the highway in a modern environment in all these different ways. I think obviously that's why mixed martial arts and violent video games and football and all that are so popular. If you just look at the money involved in female sports compared to male sports, I mean, it's too bad for women athletes, but there's just a huge difference there. Yeah, and now you had brought up studies on transgender individuals. I think it's fascinating because, especially today, because more than ever, we're able to study behavioral changes in biological men and women who then change the hormones radically. What does that do to their brain? What does that do to their behaviors? You mentioned something about blunting emotions. We had, a while ago, we had a transgender athlete and a transgender lawyer on the show. Trans woman athlete? Trans female and then trans male. And the reason why we had them on the show was because we had said that being born biologically as a male and then going through puberty and then going on hormones, you still retained a large percentage of your advantage. And so they came on to discuss this and debate it with us. But one of the things that really fascinated me was the transgender male, so this person went from female to male, they said that when they went on testosterone that they noticed that it was like you took the emotion, like if you had a light switch where your emotions are on, dimmer switch. Yes. Turned it way down and he goes, yeah, I, all of a sudden, felt like my emotions went from this wide rainbow of colors to like three emotions. Is this common when you studied this? Yeah, no, I, literally, my hair is standing on end as you're talking about it. Just to hear you say that. Because even though, again, I've been researching hormones and teaching about them for so long, the work that I did for this book on interviewing transgender people who told their stories about what it is like, including a non-binary male who, someone who's born male, who is now non-binary, who is on puberty blockers and a female who transitioned to male and then back to female. So she could report on it as a woman. So that is intense. But it was that work that was most sort of striking and powerful to me, probably because I hadn't been as familiar with the details of that literature. But what you said is, yes, that is what the scientific letter, scientific literature shows that testosterone does have this dampening effect. Again, on average. But it's what you experience. And the reason it puts my hair on end is because emotions are such an incredibly important component of our lives, how we feel our drives, our sex drive, our ability to experience joy and pain and vulnerability. So it tends to be the more vulnerable emotions that are squashed. But also, there's something about joy I also heard coming up. Anger is not squashed. It doesn't necessarily amplify, but it is one that people still have access to if they, when they transition, say female to male, a lot of their emotions are dampened, but not anger. That's one that people still feel that they're in touch with. The trans male also brought up, too, that he noticed his view of women started to change a bit, too, in terms of objectifying them. And that was pretty interesting. Like their sexual drive and, yeah. It ramped up. Okay, so remember, this is somebody who, I don't know what age this person transitioned. They had gone through puberty as a female. Oh, they were 30s. Yeah, 30s. Okay, so this is someone who, every woman knows what it's like to be sexually objectified. We don't like it. I mean, you know, some people do. Some people like a little sexual objectification here and there. That's the truth. But overall, yeah, it's not pleasant. We want to be, you know, considered for our entire humanity. So that's annoying when we know that men are viewing us as sexual objects. However, here's another area where the literature really blew my mind and changed how I view this entire thing. This entire issue. It gave me empathy towards that feeling and the struggle that men have. Because I saw, wait a minute, this has to do with this hormone. It really does. It's not just the patriarchy. It's a struggle that men feel and sometimes feel very bad about it and needs, I think it needs to be acknowledged that men view the target of their sexual attraction on average in a different way than females view the target of their sexual attraction. It's not that we don't find, you know, whoever we're attracted to totally hot and we have, you know, high libidos, et cetera. But it seems to be a very different sense of urgency and a different feeling, and it's more physically based. And I feel like that needs to be discussed and understood so that for men who we want to help men navigate that territory, I hear men say like, I don't know how to talk to her. I don't know what to say. I don't know how to talk to women. And I've always been like, what are you talking about? Just talk to them. But if you think, like from a woman's point of view, if you then think, wow, this guy, of course he doesn't know how to talk to her because that involves her brain and her personality and her whole humanity. And he's just really like physically attracted to her. How do you put those things together and be normal? Yeah. And you know, it's funny, you're saying this and any guy who goes through puberty knows what a radical and confusing shift that is. That was the most emotional time of my life was 15 to 18-ish. And I remember being in high school. I remember crying over this. I remember being so emotional that when I would leave my girlfriend's house, I was crying because we both grew up in homes that were religious and sexual behavior was not accepted. But I had this urge so bad and she would be telling me no. And I would be like, oh my God. And then I'd be trying to do what she said, focus on the movie. It was the weirdest dynamic of feeling this uncontrollable urge but then also knowing that it's supposed to be bad and I'm not supposed to do it and she doesn't want it and then trying to wrestle that as a young teenage boy and not knowing. Did you have any... I mean, this probably is a stupid question but sort of resources or anyone you could talk to. No, not that. So my father committed suicide when I was seven. And so I didn't have a dad. Oh my God, I'm so sorry. No, it's okay. My mom remarried into an abusive relationship after that so my stepfather and I did not have a relationship like that to where I could go to him for advice. My mom was very young when she had me so even her understanding and they weren't big readers so I was on my own to kind of figure this stuff out and I just remember that being one of the most difficult times of my life and then it's not socially accepted, right? It's not something that would be okay for me to be that way. Or at least I wasn't told that it's okay. By the way, I want to make a comment on this because we do have these evolutionary and biological drivers but we're also conscious social intelligent beings so this doesn't excuse bad behavior. I want to be clear on that just because we have this hormone that drives men to potentially look at things and sexually objectify women and have this drive you're still responsible for your actions. Sorry, that's the thing. It's the behavior that the thing I'm getting at is the feeling that you are struggling with. And I know where you're going. Yeah, we can judge and condemn whatever the behavior, the consequences, but no. No, I know exactly where you're going. There was nobody there to talk to me and say it's okay, this is normal, son. Yes, and it's fine. You have to learn how to behave. I felt like a bad person. Yes. You know what I'm saying? I felt like something was wrong with me because this was so hard for me. It's so powerful. Yeah, it was such a powerful thing that no matter how many times I was told that no or told that we shouldn't I was still struggling with that and so it put me on this emotional roller coaster as a young teenager. Now Carol, did you look at same-sex couples because the reason why I'm asking that is because this is me guessing, me speculating, okay, is that when you have two men in a relationship or two women in a relationship do you see the male aspects amplify What do you think? I would guess so, right? I would guess you probably see more risk-taking behavior in male-male relationships, more sexual promiscuity, whereas with the women probably less. Now, did you look at this? Yes. Okay, what are some of the things that you would see? Well, it's just so great to have these examples of male sexual behavior and male sexual culture and female sexual behavior and culture unrestrained by the limitations or needs of the opposite sex. So what do you see when you take the, when a man can have sex the way he wants because he's having it with other men, right? I just think that's great. I'm just thrilled that we're going in the right direction socially on that front to just allow that to be expressed in healthy ways, of course. But from a scientific point of view, of course we're seeing male nature expressed in a more pure way. And what's interesting is people expect gay men to have lower testosterone because they're feminized in some ways, but the sexual nature is 100% masculine. It's no different. It's what men want, gay or straight. They want to have a lot of sex and they prefer to have a higher number of sexual partners. And if you're in gay culture, you can. And of course I am not saying that this is what all gay men want or all gay men do. There's lots of monogamy in gay sexual culture too. But it's more often there are agreements that having affairs or extra pair sex is more acceptable because they get it. You can still be in love with each other and have your primary partner but have a little sex on the side. You know, I have an uncle who's gay. He passed away, but great guy. I love the guy. And I was younger obviously. We were close in age. I remember we were hanging out and we were watching at the time MTV. This is when MTV used to have those spring break shows or whatever. Yeah, I remember that. And the girls and all that. And we're watching it. And obviously he's my uncle. We're close and so we tease each other and this girl comes up in a bikini and I'm looking at him. I'm like, man, look at that. Look at what you're missing. Like, you know, we're joking. And he says, he looks at me and he goes, you have no idea. Well, you didn't know obviously he was gay. I did know. Yeah, I knew he was gay. You said, look at what you're missing. I get it. So we're teasing each other. We're very close. And it was a great relationship. And he goes, you have no idea, Sal. You have no idea what it's like. I'm like, what do you mean? He goes, imagine you go into a bar and you see a hot girl across the bar and you walk up to her and without saying a word, you grab her butt. What do you think is going to happen? I'm like, she's going to yell at the bouncer to kick me out or I'm going to get arrested. He goes, that doesn't happen in gay bars. And I was like, oh man, I forgot. You guys are all guys. I guess it's all. Right, right. Exactly. So that's an interesting, that's interesting because it suggests to me it's not about necessarily about testosterone. There might be a rule somehow prenatally, but even there we don't see any evidence for a difference. There's the sexual nature is 100% masculine and it's just great that you can sort of see it unleashed. And then of course in lesbian sexual culture, you basically have the opposite. There's just much, much less sex. Carol, have you read Sex at Dawn? Yeah, ages ago. Christopher, what's his last name? I'm just curious to what your thoughts are. So his whole philosophy is that we have evolved to not be monogamous, that we had many sexual partners and there's a huge, especially in the health and fitness space, there's kind of this movement that's been going on. Polyamory? Yes, in this direction. My argument against that is always, I would love your input on this Carol, my argument has always been that monogamy has been practiced widespread in very large popular societies and I believe. And polygamy. Polygamy as well. Official polygamy. Yeah, so polygamy much older, right? But later on monogamy. And to me it's like, okay, this also, yeah, there it is. Christopher Ryan. Yeah, Christopher Ryan. This points to the fact that yes, we are driven by our biology, but also we're smart enough to say this is beneficial for society and culturally. Yes, that is, I think that's exactly right. So there are a lot of problems that come with polygamy and it's the highest status males who can acquire the most resources are able to and can and legally can acquire the most females. But that leaves a lot of young men without the ability to acquire a mate. What do you do when you have a young, high testosterone guy who can't get a mate? He's pissed. You get violence. You get a lot of bad behavior. So just troublesome, aggressive competitive behavior and high levels of violence in a society that has that social system. So yes, this is culturally, socially a positive move, I guess, towards monogamy and having that be the legal form of long-term partnering. But in terms of the evolutionary evidence to what we're kind of designed for, there's really no evidence that the sort of evolutionary, most relevant evolutionary mating system would have been monogamy. But serial monogamy is what we're thought to have practiced because that's what's most beneficial for the survival of the offspring is for the pair to be together until the kid is something like four years old till it's weaned, basically. Because we are sort of designed to breastfeed for much longer than a year, anywhere from like one to three years. Well, yeah, because a human baby is born as a fetus, essentially. It can't do anything for itself. The mom really is not really in a situation to go hunt and provide, so it makes sense that the male would stick around for us to survive. But there's also facultative paternal investment, which means that for some men in some environments it's going to make sense to stay with one female, maybe for her whole reproductive career, maybe for a part of it. But in other environments, or for other males, a better strategy may be to just compete out on the open market. Or he may not have any other choice. So there's a huge amount of variety, and I think that probably represents differences in social systems that we had in our evolutionary past in different environments. Now, you've been studying hormones for a while. I've been talking about this for a long time. I can't imagine a more challenging climate than now for someone like you who studies what you do and talks about what you do. What are some of the challenges that you've been encountering? Because you're literally talking about the differences between men and women from a hormonal and biological standpoint, which seems to be taboo these days. Is this... I mean, are you worried about what you're talking about, or have you been attacked? And especially since now, you've got more of a public persona. Yeah. So I came... I really had a very small life before this. I mean, I was just teaching at Harvard. I had my little family. I didn't do anything really publicly. The reason that I wrote the book is because it's a challenging time. Oh, I love you. So it is because I felt like I'm in a position to speak up. I have a... We're financially secure, basically. So I do... This is so important to me because it's science, which is... I love, has changed my life from somebody who is confused and lack direction to someone who is learning to understand the world with this incredibly powerful tool. And I feel like people are trying to take that away and that the favored viewpoint that gets repeated in the media, in the New York Times, in the Guardian, there's these favored interpretations of reality, which are not true. And it's what seems... I hate to say it, but what seems politically correct and sort of these feel-good stories that we're basically all the same and sex isn't real and that should give us hope and that should increase the rights of people with all kinds of gender differences and we can accept each other better if we believe that biology isn't that important. That's just completely confused. We can do all that stuff and pay attention to biology and understand the facts. And as a science educator, as someone who came really from the bottom up from literally studying chimps and just being fascinated by how all this works, I didn't come in with an agenda. And the only agenda that I have is that science is the one place where I feel like people can come together and can agree on the facts and that is being taken away. Where are we going to come together? There's so much divisiveness and I'm really, really bothered by that. So I wanted to step into it. But amazingly, I'm getting so much positive feedback because I think when you tell people the truth, you're respecting them. I was respected as a young scientist when I became emotional. There was a seminar I attended as a grad student when I became really emotional about a hypothesis about whether rape was an adaptation in humans. And I said, this guy's an asshole. The guy who wrote the paper. And I rejected the hypothesis because it made me upset. It felt wrong. But that's not how you're supposed to work to understand the world as a scientist. You're supposed to look at the facts. You're supposed to dispassionately evaluate hypotheses. It's supposed to be amoral. Like you got to remove that. Yes, yes. You want to understand how the world works and if it is an adaptation, I certainly want to know even if it is hard. So the professor in that seminar, instead of saying, oh, are you okay? And like coddling me, said, look at the data. What do you think of the hypothesis? Evaluate the hypothesis. And I realized in that moment that, yeah, some truths can be painful, but I'd much rather know them and learn how to think critically about the facts and the world. And that is what I want to try to give to anyone who's interested through my book, is the truth. But still being compassionate and fighting for human rights and the rights of people with all kinds of differences, which I am very passionate about. And I really think you can do both. So I'm trying to do that and I'll take whatever's coming. But I've had a little bit of blowback about like appearing on Joe Rogan or the people who sub-tweet me had said something transphobic at some point. But I would, first of all, I think Joe's great. I think you guys are great. And what if you said, if you made some comment like two years ago that I don't agree with, I don't really care. Like that's not what it's about. You're trying to do the right thing. You're trying to understand the world. And so I don't like this idea that if you are associated with someone and other people don't agree with all of their ideas, like you're a bad guy for associating with them. That's ridiculous. We need to come together and talk. And so that's why this you doing this is great. What comes to mind, Carol, or do you have concerns when you hear things like toxic masculinity? Yeah, I understand why people want to use that term because it seems like, you know, and there is some truth to this obviously, the sort of most dangerous aspects, and maybe to some degree most disturbing aspects of human behavior are committed by men. Predominantly. Like murder, rape, et cetera. But you guys aren't murderers as far as I know and rapists. No, I serve my time, I'm good. But you know, most men are not those things. There's, and that's the extreme end of bad male behavior, right? That's out on the extreme. Some cultures there are some differences, but also we were talking before you started taping about, I think before you started taping, but even while we were taping about you guys, your devotion to your kids. Oh, yeah. And I know that part of why I love my husband is because of his masculinity and his feeling protected, and I'm not saying this is true for every woman, but his stoicism, that is stuff, yeah, bothers me here and there, but ultimately I think that we're a pair, we fit together, we complement each other. There's so much beauty and masculinity. And I have a 12-year-old boy and the term toxic masculinity pisses me off because it's, I think it has become associated with just plain masculinity and people are feeling, no one should feel bad about their natures. It's behavior. And if we could, I don't want masculinity to be toxic. I don't want the behaviors associated with that to be toxic, but women do a lot of nasty stuff that really hurts people too. Shouldn't it just be called assholes? Yeah, thank you. But there's like a particular, yeah, I mean, no, I agree that's what you want to deal with is assholes, but there's like a particular brand of asshole who's like, okay, this morning, I'll just say, because I went for a run. I've never been here before. I went for a run, which I thought was going to be, sorry, I don't want to insult anything, but there's some park near her where I thought I could go for a long run. Yeah, here you got to be careful where you go. But so I went and I started feeling really nervous and I started feeling like, is this a safe place to run? I'm by myself. I don't see any other women. In fact, I don't see any other runners and nobody can see me. Nobody can hear me if I scream. And a lot of men might not understand that that's just so the whole way I was nervous. I was like, am I going to get raped basically? So that maybe is toxic masculinity or men like harass. I have a gay friend who is saying that he goes to the gym and he's small and that he gets harassed by these big tough guys at the gym. And he's like, no, because we had this conversation about toxic masculinity and he's saying, no, that's what that means. So I get it, but I don't like it because it's not fair to masculinity. Yeah, and there's a difference between... I don't think it's helpful. How is that helpful? No, I'll give you an example. Like, okay, aggression could be labeled a masculine trait, but aggression is not the same as violence. Right, so physical aggression. Yeah, right. Or drive or risk taking. But risk taking can be taking a chance with my business or it could be me doing crazy drugs on the street with a dirty needle or something like that, right? Which men were more likely to do. This is such a fascinating subject for me and I love looking at the differences generally between men and women, and especially the dysfunction. This is why I think you see a lot of interesting things. For example, you're going to see, generally speaking, more men who are violent towards other people physically. That's a very, I guess to my estimation, a maladaptive form of maybe masculinity. But then with women, there are cases where you see, for example, what's that disorder where the mom will poison their kids slowly? Munchausen. Munchausen. That often doesn't happen with men. That's much more of a common, and it's almost like a maladaptive dysfunctional, part of being feminine because you want to take care of, you want to be nurturing so you're making your kids sick so that they constantly are dependent on you. We're bullying people on social media so they end up killing themselves. That's more of a thing that women are doing, men aren't doing that as much. But I do think it's important to say that in terms of differences, men and women, compared to other mammals, there's really small, general differences where you see the big differences are on the extreme. That's right. So if you look at in the middle, we're pretty similar. But if you go to the most violent people in the world, the number one, like a 1% violent people, it's probably 97%. That's the problem that I have with that, the toxic masculinity is then you get like your son, who's only 12 years old, who hears that term thrown around. And he's a sweetie. Yeah, and then he starts questioning if some of his behaviors is falling in that category, which he probably has no business even having to worry or think about it because he's not that in this picture. No, and I love what you said about how you felt going through your adolescence. Women are always celebrated for becoming a woman, right, going through that period. We celebrate that. We need to celebrate that in men too. It's the same. That should be a beautiful thing for you to go through that and to become like a sexually viable adult that has other responsibilities associated with that. That should be positive. Well, you know, cultural, lots of cultures have coming of age things for boys because with girls, I mean, I have an 11 year old daughter. She's probably going to get her period soon. So you get this very physical sign of, oh, I'm now a woman, right? Right. What do we, what do guys get? Like we get hairy. I mean, you know, there's really nothing. Uncomfortable boners. Seminal emissions. Yeah, exactly. There's not this big like, you know, like, oh, here it is. They're nocturnal. Sorry, no, seminal. Nocturnal. Nocturnal emissions, right? So, but lots of cultures have those and I think that's probably what you're talking about. So the guys don't always know, oh, this is the next. And also with toxic masculinity, what is the term for you guys taking physical risks to help people you don't even know and putting your own lives at risk? You do way, way more of that than women. Women certainly do it, it happens, but that's overwhelmingly like a male territory. And that's an amazing part of masculinity. Is that kind of physical heroism? Yeah, although you take a, you put a mom's child at risk. That's right. No, that's when you see, that's when you see moms putting their lives at risk. I saw my mom who is, she's deathly afraid of dogs. She's not a dog person. And she had, at the time my son was a baby putting him in the back of the car and the neighbor's German shepherd jumped in the back, friendly dog, jumped in the back of the car and my mom physically threw this dog out of the car and screamed like a lion. And I was like, I heard it in the house. And I was like, that, you did that. I could totally relate, I could relate. Yeah, that was because she was being protective. Yeah, no, that's true. I mean, so women definitely will put themselves at risk for their offspring, but men are much more likely to do it for total, you know, just strangers, which is amazing. So now these differences, these general differences that we have, let's focus on just because you're, the book's on testosterone and because I feel like masculinity is much more attacked these days than femininity. What are the benefits or why do we need a lot of these masculine traits? First, let's list them off and then what are the benefits today? We don't hunt anymore. We're not at war all the time. Society's far more safer than it's ever been. Like what are the, why do we need them in the first place? Why can't we just homogenize and all become the same? They throw a lot at me. First of all, boring, boring. And I would just say that the practical impediment there is that we are designed to be through natural and sexual selection to be attracted to our compliment in a way. And that's even, you know, to some degree within homosexual relationships where there's kind of a... Yeah, there's normally a very opposite. Even if it's the same sex, the one partner takes on certain traits. Yes. And I think that there's a separate question about what society would be like, if say we castrated men, right? So first of all, I think it just wouldn't work because we have these needs, right? But second of all, the things that you guys have all been talking about, although I can't say like this study found that testosterone causes this thing that seems to be like this drive towards a goal that seems to be different, right, between the sexes, needs to create, to take risks. One year in my class, I asked my students just to have a conversation about what would the world be like if we castrated men. And somebody said, I don't think we'd have tall buildings. And I thought that was really interesting. And who knows, you know, it's possible that that kind of... those kinds of technological advancements. I don't want to say that women don't play a role because of course they do. I think the risk-taking involved with that is probably where you're... Yeah, but something to do with that, you know, we get to have babies. I made a baby in my body. I created a human, you know, with my husband's DNA, whatever. But I'm the one who grew it inside of me. Oh, I'll tell you what. I used my boobs and the milk that I made to grow him after he came out of me. What else do I have to do after that? I made my kid. I'll tell you what, watching that as a man, I'll tell you what, I'm a very involved father. I have three children. And watching my wife... I just had a... We have almost nine month old now. And watching her... And I remember this distinctly with my oldest son, right? Because this was the first time I had a kid. I remember, you know, at the time, this was my ex-wife, she was pregnant. And, you know, I knew that there was a baby. I knew that we were going to have a kid. But I was jealous because of the connection that she had that I didn't feel till he was born. Like, until he was born, it wasn't... I wasn't connected like she was. And I think that that's something that isn't valued or celebrated enough. Like, that is a remarkable thing that men just... Who knows in the future if we'll be able to experience this with, you know... I feel like motherhood in general isn't celebrated enough. Oh, yeah. I agree. There's been a decline on that for the last... Okay, it's true. 100%. Yeah, no, I have a lot of mixed feelings about that because like I just, you know, I teach. I just wrote a book. I'm super busy. You know, that's rewarding. I'm trying to make an impact, you know, in the world now and not have my tiny little life. But at the same time, I do... And that's all been great. And I've challenged myself and grown from it. But the most important thing to me is I want, you know, to have more time. I feel like, oh my God, I'm... I don't have enough time with my kid and my husband. And it's... You know, I feel pulled in so many directions. But if I had to choose, I'd totally choose being a mom and just have my family. Yeah, no, that's a struggle I think a lot of people go through. But I think generally speaking, you see that a lot with moms. Whereas with dads, maybe not as much, you know... Well, because you know that you have someone... I mean, a lot of really successful men, of course, know that their kid is being loved, hopefully, you know, and cared for and they have the support to go and pursue what they want. So there's that too. But I think that is a real constraint on women. But I mean, it doesn't have to be a constraint. It's a joy for so many women. Yeah, and I think that needs to be celebrated and respected. And it would be great if we could get paid for that and have more economic independence. Because that's a big part of it. A lot of women, you know, it's very, very tough to have to be economically dependent on somebody else. Yeah, that's an excellent point. Carol, was there anything that when you... Since we've been talking that we haven't covered that you feel is something that's grossly misunderstood about testosterone? I know we've talked about a lot of different things right now, but in your research and writing the book, you know, is there something that we haven't touched on or talked about today that you feel like that is still misunderstood about testosterone? Well, there is one point that a lot of critics of the importance of testosterone in athletic ability try to use as a sort of counterpoint. And they will say that individual differences, you know, if you look at... Testosterone really doesn't help sporting performance because if you look at testosterone levels among men, it's not always the case that the one with the highest testosterone level beats the one with the lower testosterone level. But an oversimplification of athletic performance. So I just want to say that in some... For some sports that is the case, but that's not the issue. The issue is why do men just totally blow away women in sports, which they do. It's a fact and it's okay, right? That's how... I mean, yeah, it might suck for women, but that's how it works. It will suck for women, of course, if men and women are playing have to compete with each other, women will lose, right? So the point I think that's misunderstood is that that is a tactic that testosterone critics use is to say testosterone is not that important because within sex, it doesn't all... You can't predict like libido or aggression or athletic performance in a lot of cases. And that's true, but it's not about within sex. It's about we're trying to explain sex differences in a lot of different things. And it's the whopping, you know, 10 to 20 or higher times the level of testosterone that you guys have in all these different phases of life, in utero, in puberty, in adulthood that we don't have. They give physical advantages that everybody knows about, like way more muscle and way less fat and body size and bone strength and hemoglobin. And it's not about the little differences within sex. So that is just something to keep in mind that those levels, those differences within men and to some degree within women, although women it's more impactful, those just aren't anywhere near as important as the differences between sex. And I think that's also when they make that comparison, I think it's silly because if you take the same individual and give them more testosterone, you will see an increase in performance. But there's also... And muscle. Yeah, and there's also androgen receptor density. Yes, yes. Just how good, how proprioceptive you are and your athletic ability. I mean, I could have higher testosterone than a pro basketball player, but he's gonna crush me on the court because he's so skilled. Right. Are there any negatives to testosterone? Like we're talking about what it does and potential positives and influences on behavior. Are there things that tend to cause detriments? I know men tend to not live as long as women. Is that due to testosterone? Yes. Okay, all right, let's talk about some of those. I mean, there's, you know, it's a cost. So it's an energetic cost. Growing muscle is very expensive. So there's the effects on... There's the energy spent on muscle. There's the energy spent on physical activity, on risk taking. So, you know, more men die young from accidents for one thing. So that reduces life expectancy in males. There's immune system costs. So there are different diseases that the sexes get at different ages. And so testosterone can have some negative effects on survival, sort of on longevity. But I would say that the biggest negative is the, is physical aggression and sexual assault. And those, I think, are ultimately products of testosterone. The important piece is the power of culture in shaping the expression of those natures, right? So we know that cultures that have much stricter laws and social norms that, you know, really strictly prohibit those kinds of negative behaviors, we see that men are able to control their behavior, right? So this isn't something that has to be played out. We have to remember how important culture is. So one big misunderstanding is that people are, you know, people are arguing all over the place about nature versus nurture. Is it testosterone or is it culture? It's both. And it's so clear that it is both and that the family you grow up in, the, you know, laws in the country you grow up in, your religion, all of those things are going to shape how we express our nature. So like that's the most important point is appreciating the power of testosterone and biology in no way means that culture doesn't have an influence. It doesn't change our natures. You know, we're going to have these different natures. And what matters is how we express them. That's such a great point. One of my favorite examples of that, you know, there was a documentary I watched a long time ago that was just so interesting. I think it was called Knuckle. And it talked, it was a documentary on, they called themselves Travelers where they, they live in these RVs and they're in Ireland and they kind of follow, yeah, and they follow their own Knuckle. It sounds interesting. It's really good, right? And they, the way that they handle conflicts within each other's families or with other families is they bare knuckle box. Now here's the thing though. Now here's where the culture comes in, right? That's the aggression part, right? That's the instinct. The men are going to fight, right? But they don't just all attack each other and kill each other. It's ritualized. They have rules. Okay, you pick someone from your family. We pick someone from our family. Here's the rules. Doesn't the movie Snatch to pick this? Yes, Snatch does that too. Look at mixed martial arts. That's obviously culture's influence on this natural tendency to be violent. We're not just killing each other. We're like put on gloves. You can't poke each other on the eye. You have to weigh the same amount and all that stuff. So to me that's a great example. So they're acknowledging the nature and channeling it in a way that works for that culture, right? Yes, yes, yes. So that's one of my favorite examples of that. Well, this has been a great conversation, Carol. Yeah, you've been one of my favorite guests. Thank you so much. Yeah, this is really, really fun. Sal, Justin, and Adam. You got it. Thank you. Nailed. Everybody else. I appreciate that. I highly recommend this book if you want to know anything about behavior between the sexes and just testosterone in general. It's very, very good. And there's lots of... It's really written in a way that the biology, the science should be accessible to anybody, even people who don't have a scientific background. There's lots of stories. There's my own personal stories in there. So there's a lot of narrative. I just think it's a very important message right now because I just feel like it's... For some reason, it's taboo to talk about the difference between men and women right now. It's that we're supposed to... It grounds us back to reality. Yeah, there is no difference between the sexes. No, and you are always responsible for behavior. And we are all individuals. I firmly believe that. But I think ignoring science is dangerous. And as soon as science becomes politicized, we're screwed because it's one of the last objective fields. Exactly. That we have almost nothing as objective anymore. We work in the fitness space. And I can't tell you how much information is driven by complete bullshit. Just terrible. No science whatsoever. And it's terrifying from a fitness perspective because I'm like, no, that's not true at all what you're reading. That's obviously driven by somebody's agenda. People have to know who to trust. They have to have trusted sources of information. And we're losing those. Yes. No, I do have one question. This is interesting. I read this, and I actually read studies on this that backed this up. I would love your opinion. So apparently, this is weird. The difference between your ring finger and your index finger. So if your ring finger is a lot longer than your index finger as a man, that means you were exposed to more testosterone in utero versus if your ring finger was short. Oh, I thought you were going to do a size thing. No. Apparently the size between. No, is that true? So I have a section on that in the book, and I have a little diagram showing you how to do the measurement. So I am like... That's rare for a female. I'm more masculine than something like 90% of men in terms of my 2D40. So that's just because... So if you measure from the bottom wrinkle to the top of the bone on this one, on your index finger, and then same thing on your ring finger, and then calculate the ratio. So I think I'm like 0.89 or something. And what this actually is... So people have published a lot of studies on this and it's easy to measure it. And just anytime you're looking at... Anytime you run any study where you have males and females and you want to be able to say, oh, I got an index of the level of testosterone they're exposed to in utero and all I have to do, it's easy to do this measurement, right? You just get a Xerox and then you can measure it. Definitely. Although people probably don't even use Xerox anymore. So a lot of people are publishing these studies and saying it's associated with like athletic ability or libido or aggression. Those are the studies that get published. The eight zillion studies that measured it that didn't find it was associated with those things don't get published. That's called the file drawer effect. That being said, there was a sex difference. So that's clear. But to see it, you need a lot of people. So it's not a huge effect. You need a large sample size. But yeah, what I have is unusual for a woman. Most women will have... And this is an estrogen effect also. And it's interesting to be cut. Well, whatever. I'm not going to go off on another tangent. So women will tend to have the index finger the same size as the ring finger or a little bit longer. And that's sort of a feminine look. Like their fingers are important indexes of estrogen. I think that's why the nail industry is so popular because you want to have that long sort of slender look on your fingers. That's fascinating. So I think it's the evidence there is not super robust but there is a sex difference. It is related to testosterone exposure. We see it in non-human animals. It's kind of fun. You can Google it, but I wouldn't put too much faith in anyone's individual measurement and what that predicts about that individuality. When you're gone, we're all going to compare. Yeah, right. As soon as you walk up to our brochure, I want you to allow... I've never heard anyone say that before. Would you call the file drawer effect? So that is publication bias. And it is an issue in science and we're making some advances there and people are publishing pre-registering studies and the hypothesis that they are testing. And this study would then get published whether or not that hypothesis was supported. But what happens in publishing is that exciting, unusual results are published. They may or may not be replicated, but who cares because it's already been in the New York Times and on the CNN and everybody's super excited about this one little thing. So what we want to see before we join in conclusions about how the world works and plus we should always think critically about those conclusions, what we want to see are studies that are well replicated. Those are robust findings in different populations with slightly different methods, not just one or two studies that uses a very narrow range of methods. So the file drawer effect is what happened to me with that study on pornography and testosterone. I never published it because it didn't work. Like it didn't show that this manipulation changed testosterone levels. So there's no study out there showing don't do what she did and try to manipulate testosterone levels with pornography because it doesn't do anything because who's going to want to publish that? So what we see are the positive results, the interesting results. So that's the file drawer effect. I just put it away. That's fast. That's like when we see those articles that say compound and chocolate burns fat. Maybe you got to read all the other stuff. Eating chocolate actually makes you gain body fat. Carol, again, one of my favorite guests. Thank you so much. Talking to you. Thank you so much for what you do and thank you for writing this book. Great. I hope you like. Absolutely. Thank you. Look, if you like our information, head over to mindpumpfree.com. Check out all of our free guides and free information. You can also find all of us on Instagram by identifying Justin at Mind Pump Justin, me at Mind Pump Sal, and Adam at Mind Pump Adam.