The Jordan Harbinger Show - 280: Sarah Hill | This Is Your Brain on Birth Control

Episode Date: November 21, 2019

Dr. Sarah Hill (@sarahehillphd) is a leading researcher in the dynamic and rapidly expanding field of evolutionary psychology, and the author of This Is Your Brain on Birth Control: The Surprising Science of Women, Hormones, and the Law of Unintended Consequences. What We Discuss with Dr. Sarah Hill: How hormonal birth control affects women -- and the world around them -- in ways we are just now beginning to understand. Why a woman will be attracted to a certain partner while taking hormonal birth control -- and the problems this could cause for a relationship when she stops taking it. On a hormonal contraceptive, a woman is twice as likely to have attempted suicide as a woman who was not on a hormonal contraceptive. Why, in spite of its drawbacks, Sarah credits the pill to her own ability to achieve a doctorate and career success. Why these new findings should be a rallying cry for women to demand more information from science about how their bodies and brains work and to advocate for better research. And much more... Full show notes and resources can be found here: https://jordanharbinger.com/280 Sign up for Six-Minute Networking -- our free networking and relationship development mini course -- at jordanharbinger.com/course! Like this show? Please leave us a review here -- even one sentence helps! Consider including your Twitter handle so we can thank you personally!See Privacy Policy at https://art19.com/privacy and California Privacy Notice at https://art19.com/privacy#do-not-sell-my-info.

Welcome to the show. I'm Jordan Harbinger. As always, I'm here with producer Jason DeFillopo. On the Jordan Harbinger show, we decode the stories, secrets, and skills of the world's most brilliant and interesting people and turn their wisdom into practical advice that you can use to impact your own life and those around you. We want to help you see the matrix when it comes to how these amazing people think and behave and help you become a better thinker as well. If you're new to the show, we've got episodes with spies and CEOs, athletes and authors, thinkers and performers, as well as toolbox episodes for thinking. like negotiation, public speaking, body language, persuasion, and more. So if you're smart and you like to learn and improve, then you'll be right at home here with us. Today on the show, Dr. Sarah Hill, birth control and hormones, such a fascinating subject. The birth control pills hormones go all over your body, so they affect everything, your immune system, your hair, your mood, anxiety, etc.

There's some extreme side effects when it comes to this. If you're taking the birth control pill just to not get pregnant, well, it's like dropping a bomb on your house to blow out a candle. It'll do the job, but it won't only do that job. So today we're going to learn why you should not choose a life partner or make big decisions while on the pill and what to do instead. How to defend yourself against depression or other mood issues that might be caused by the pill and other hormonal stuff? Why and how to take breaks from the birth control pill and when it's time to give your body

and your mind a break. Guys, this is for you too. If there are any women in your life anywhere who might be affected by this, then it affects you too. And besides, you can't tell me this stuff is not absolutely fascinating. I really hope you all enjoy this episode as much as I enjoyed recording it. And if you want to know how I managed to find all these amazing people, I find them through my network. Check out our six-minute networking course, which is free over at Jordan Harbinger.com slash course. It's great for business. It's great for personal. And it's great for not being that guy who has to call in two years and go,

hey, I know we haven't talked, but I need a job. Trust me, this will change the game for you. And it takes a few minutes a day, Jordan Harbinger.com slash course. And by you. By the way, most of the guests on the show, they subscribe to the course and the newsletter, so come join us, and you'll be in great company. In the meantime, here's Dr. Sarah Hill. The pill changes us because it changes the version of our personality that we express. And it's funny how obvious that sort of seems to be after having read it, but then when you think about the birth control pill, I don't take it, obviously, but I would say that most people

who take it think, eh, it switches your ovaries off, I'm good, it just does something down there and we're all set, we don't think this changes my entire body's hormone profile, therefore all my behavior, therefore my personality, therefore all of the things that make me, or if I'm taking the birth control pill, which I never have, if I'm a female, I'm taking this, all the things that make me, me are now getting like, the dials are coming in and getting messed up by this, and we're not necessarily cognizant of that. Right. I actually, you know, I'm a psychologist, and I've spent my career studying women and even studying the effects of women's sex. hormones on motivation and who they're attracted to and, you know, their sense of self, I still had

a blind spot with the birth control pill. I still, I was on it for more than a decade. And during that time, I was studying women and the things that make them tick, including their hormones. And I never put two and two together, which was, you know, a really embarrassing sort of place to be. But I think it goes to show that, you know, for many of us, we just don't really think about it. It's like, because we're taking it for this one set of reasons. We never think about the fact that, oh, yeah, I'm taking sex hormones. And sex hormones have their fingers in so many pots in the body that they're going to be influencing, you know, systems ranging from our circulatory system to our immune system and hugely our brain because there's probably no place in the body that has more receptors for sex

hormones than the brain. That, of course, makes sense. And I know that you're telling your own story through the book, which I think is kind of cool, brave thing to do. A lot of, this isn't a medical text, but a lot of books about this stuff, I don't know what it is, but sometimes the author's like, I don't want to talk about my own stuff. It's a little too vulnerable. Let me speak in these sort of weird generalities, and it makes it harder to relate to it. As a man reading a book about birth control and female sex hormones, it's already a little tough for me to kind of put myself in those shoes. So I appreciated the way that you wrote that and the way that you were really open about all of that.

There's a piece in the beginning where you say, look, I went off the pill, I suddenly had more energy, I started doing more hobbies, things you had, I guess, probably abandoned a few years before. You felt more alive, and you said it was like walking out of black and white into color or something along those lines. And I thought, wow, that is a really dramatic difference. It's not just like, oh, I'm sort of more cheerful,

or I want to go out more. It's like a completely different way of looking at the world. Yeah, it really felt that way. I felt like I woke up, And it was sort of funny because it was about three or so months after I had gone off of the pill and I was in the car. I still remember this moment because over the course of that three months, I'd sort of begun to feel like I had more energy and things just seem more exciting. Like life just felt exciting. It felt like there was like opportunity kind of, you know, around any corner. And I just felt energized and alive. And again, you know, it was like as I wrote in the book, I started exercising again. I was like noticing. men and it was just like, I just felt invigorated and I thought that I had outgrown those things. You know, I went on the pill, you know, end of high school, early college. And, you know, during that time, of course, your life is changing in a lot of different ways. And I had assumed that I was sort

of maturing out of exercise or maturing out of noticing men or maturing out of, you know, having energy and just kind of feeling spunky. And then, you know, flash forward three, months after going off of it after I had been on it for more than a decade. And I was in the car with my husband and we were driving home from dinner. And I remember, and again, this is after I had sort of had this experience of, you know, kind of listening to music again and going to the gym again. And I remember I looked over at him and I said, I feel like getting into trouble. And he was like, what does that mean? And I said, I have no idea. That's funny. So it's almost like you got younger. And also he was probably like, this is the best night of my life.

He's like, let's tear it up. Like, I don't know what you have in mind, but let's go and do all of those things. It was. It was like I felt like myself again, like this person that I was before, you know, and again, I thought that I just matured out of these things, that I just, you know, no longer felt it necessary to listen to music or to go to the gym or to feel sort of feminine and sexy. and like in tune with like the sort of those parts of my personality. And then to have it all back, it just really sort of changed my view of things and especially my view of, you know, the birth control pill that I was on. Yeah, I can imagine, man, that's just putting myself in his shoes for a second. That's a lot of pressure.

Like you're driving home, you're kind of full, you're not really sure what's going to happen. You're looking forward to climbing in bed. And your wife's like, hey, once in a lifetime chance to probably get me to do something that I should know better than to do. And he's like, well, let's go to Starbucks and get some coffee. It's gonna be a long night. Yeah, that's really funny.

And you hear things, this is outside of what you've written. So if I get outside of it, stop me here. But I see friends of mine who take testosterone replacement therapy, right? They're getting these shots either because of a medical issue or because they're 55 and they have income that they're happy to part with. And they kind of report the same thing. They're like, it's like college again or it's like my late 20s again. I mean, they're just really, really different people.

And they're like, yeah, I think I want to get into boxing. And I'm like, who are you? You played bridge last week. and now you want to start boxing? Who are you? So it does change so much about you. And we don't think of the birth control pill as kind of the anabolic steroids for women in a way.

I know that's not an exact comparison, but it's got to be somewhat apt, right? Well, yeah, and it's so funny that you said this. I actually just had a conversation today with a friend of mine who's a man who's on testosterone therapy. And he said when he was reading my book, he felt exactly the same way. That's just really funny that I just had this conversation.

not more than two hours ago. So the pill is almost in some ways, you can think of it as being like the anti-testosterone therapy because essentially what it's doing is it suppressing women's, you know, sex hormones, right? So it's like suppressing their levels of estrogen, progesterone, and also in a huge way, testosterone. It's sort of almost like being a 55-year-old man

and wanting to play bridge. Yeah. And so, you know, we have these generations of women in their 20s who are doing this. And so for me, yeah, going off of it felt like, I think, very similar to what it feels like for men when they're doing testosterone therapy and they're being reintroduced to their sex hormones because it's like our sex hormones are part of what gives us, you know, our sort of joie de vivre.

Yeah. You know, it's like part of what makes life exciting and it sort of makes the, you know, turns the volume up and makes our whites brighter and our brights brighter in terms of our sort of experience of the world. Right. Walking out of black and white and into color. And the note that I'll put on this, and I think you did put this in the book, but anabolic steroids, you can't just roll into a pharmacy or go online.

Well, you can go online, of course, but you can't go on Amazon or some pharmacy website and be like, oh, I'm going to grab a bunch of this stuff. Or like, hey, my friend told me that he's doing it, so I'm just going to go grab some of these. I mean, you're injecting these. They're super controlled. They're highly illegal without a prescription. And the birth control pill, I mean, there are 14-year-old girls whose moms are like, yeah, I don't know.

I can't keep an eye on her all the time. So let's just go get this crazy life brain-altering drug and give it to her in the middle of this time in her life when her brain is changing and her preferences are changing. Her body is changing. But no, let's like medicate her every single day of this artificial stuff. Like what could go wrong? Yeah, exactly. Yeah, I mean, there really is, you know, we've been really cavalier with women's hormones in a way that we haven't with men. And you're right.

It's like it's very well illustrated by this sort of paradox, you know, where. it's men are not allowed to be on anabolic steroids for, you know, a long period of time and they're illegal, so that way men won't use them anyway. And with women, yeah, we start them very young sometimes when they're like 14 or 15, and sometimes it has nothing to do with even sex. You know, because pregnancy prevention, you know, in some cases, because pregnancy prevention is so important in terms of women's ability to advance themselves and sort of stay out of the poor house, You know, I can understand even in some cases if there's young girls who are engaging in a lot of sexual behavior and they're not being careful that in some cases it still might make sense to give them the birth control pill while their brain is still developing. But most often what I see as being the case with these young adolescent women is that they're going on the birth control pill for reasons that are far less sort of consequential in terms of the big picture.

So these women are going on it for things like, you know, clearing up their skin or trying to, quote-unquote, regulate their cycle or trying to make their menstrual cramps less painful. And, you know, in some cases, with all of the information being out there, this might still be the choice that women make. But I think that it's, you know, goes to illustrate that we've been really, really cavalier about this sort of idea that we should change a person's personality and who they are and their experiences in the world. So that way they don't. have menstrual cramps. I think that if we actually think about what hormones do and we like sort to take our blinders off to it, we might begin to sort of treat this as a serious issue because this is a big deal. It is. And it's a little scary. When I was in college, I had a bunch of athlete friends and some of them were using anabolic steroids and things like that. And I remember hanging out with them and being like, guys, you know, you got to take this seriously. And they're like, we do. We research online. Look, our friend, so-and-so, he's the guy who gives him to us and knows all this stuff about it. And I met that guy.

bear in mind, this is a drug dealer, okay? And he goes, yeah, you know, I will only let these guys stay on it for six weeks at a time or depending on the other stuff, 10 weeks at a time. That's all they can do for the next six months to a year. It really depends. We want blood markers. I'm like, this is a drug dealer in university who's doing this. But no, if you want the female variation, you just go, yeah, you know, I'm a little crampy and they're like, here's a pill that you can take forever. And, you know, what kind of side effects? I don't know. Let me know if you have any other weird side effects. Like, I don't know, you get massively depressed or all these things that can happen. And there's something wrong when the local drug dealers sell steroids to the football players at some university is more careful than the doctors dishing out birth control pills. Like there's a big problem here. Yeah, no. I mean, and it goes to show you, like, just how disconnected we are from what the pill is really doing to, you know, like what it's being prescribed for. It's like, I think that we've all sort of had as a culture this, like major blind spot because doctors are, they're prescribing this. And, you know, I think that most doctors aren't terrible people and that they, you know, care about the welfare of their patients,

but this idea that will give women, especially when they're young and their brains are still developing. And sex hormones, in addition to, you know, sort of the day-to-day things that they do when you're a grown-up in terms of like sort of fueling sexual desire and your sort of feelings of being alive and other things, they also are like the head contractors in the remodeling project that goes on in your brain after puberty. So, you know, we don't, you know, we don't, yet know from research whether or not taking the birth control pill during times, you know, this like post-puberal brain development time, which is still going on in pretty full effect up until you're, you know, like 19 or 20, we don't yet know whether or not the birth control pill is influencing

the way that women's brains are being organized and there's almost no research on this. And so, you know, when doctors will give this to these young girls whose brains are still developing and we don't know whether or not this has any impact on the way that their brains are being laid out and then allowing them to stay on it for in some cases. I mean, now I've met women who've been on it for 20 years without stopping at all. And there's no research on that either. It's like nobody's really stopped to ask the questions. And so, you know, part of what I wanted to do with this book, in addition to just highlighting, you know, sort of what we know, what we don't know is just, you know, sort of wake everybody up to this blind spot, because I think it has been. I mean, the fact that I

studied hormones and women's motivational systems for years and yet was on the pill and never put two and two together, and I'm not a complete idiot. I mean, you know, I have my moments of being, you know, like having my head in the clouds, but, you know, I should have made this connection. I think that there's a lot of us who just haven't done that. Yeah, it is a little surprising, right? Because I read the book and I went, all of this completely makes sense from everything I've ever studied about hormones. And I'm not a doctor or anything. But I think, when you're taught that something does a specific thing, you don't necessarily go, oh, well, how does it work?

Okay, what does that affect have on the rest of the endocrine system when you're like a GP or another kind of doctor? And theoretically you should, but, I mean, there's only so many hours in a day and you kind of look at all the other doctors, they're doing the same thing, and you're a first, your second year physician, and you're like, well, who am I to question all of this? I mean, nobody else seems to have a big deal going on here. Yeah, no, I completely agree.

And even for me, you know, I had, like, once I had the epiphany and sort of recognize that, oh, yeah, of course. Of course, taking the birth control pill was going to change what my brain was doing and totally changed the way that I was experiencing the world. It was sort of like you said, when you were reading the book, you were like, well, of course. Of course this happens.

Yeah. I had the same reaction to my own thoughts. Like, wow, of course the pill is going to change everything. It's going to because it's changing your endocrine system. And that's like one of the major communication systems that creates the experience of being the person that you are. And you're right. I think that a lot of it has to do with, you know, we take the pill for this very targeted reason. And so we just don't spend any time thinking about the other things

that it's doing. And even as a psychologist and somebody who studies biological processes that influence motivation and sort of our experiences in the world, it didn't occur to me. And so I'm hoping that with the book that it's really going to give people this sort of face palm moment where they're like, of course, of course this is what was going on. How stupid of me. I was stupid. How stupid. of me not to have thought of this before, which was how I felt when it finally dawned on me that that was what was at hand in terms of the differences in the way that I had felt once I went off of it. So let's get into some of the specifics on how this changes your body, your mind, your

behavior. One of the first things that you discuss is that it messes up the cortisol response. So what does that mean? I mean, we've heard of cortisol, it's the stress hormone. Don't I want to inhibit that? Does that mean I'll feel less stress? What's going on here? Why is cortisol important and why is messing it up a bad idea?

Yeah, so, you know, cortisol is kind of like, the red-headed stepchild of hormones. And it's because, you know, cortisol is associated with stress. And so most of us tend to think about cortisol as being a bad guy. But cortisol isn't what causes stress, right? Life is what causes stress. Like being stuck in horrible traffic, right? Or being rejected. These are the things that cause stress. And like on the positive side, there's also like Christmas morning and falling in love also caused stress. So like life is what causes stress. Cortisol is just they're trying to clean up the scene. You know, cortisol rather than being sort of a bad guy is a hormone that gets released in your body because it actually helps our bodies cope with stress.

And so it does this in a number of different ways. So like one thing that it does is it dumps fat and sugar into our bloodstream. So that way if we need to make a fast getaway from, you know, like lions or tigers that are chasing us, we can. It also primes our brain for sort of learning and memory. So it is associated with the birth of new neurons in the areas of our brain that are associated with long-term memory. So it's basically flagging things as being important and moving them into our long-term memory. So that way if something similar happens, again, we're ready for it. And we're better able to adapt with whatever stressful situations we're in right now. And then also that we're going to be encountering in the future.

And so cortisol actually does a number of things that help us cope with stress. The thing about cortisol and the way that it sort of influences the way that we respond to stress is that because it's doing a lot of things to help our body cope with stress, it means that it's actually redistributing effort away from other things that our body is doing. So things like, for example, immune system, you know, sort of function and cell repair, right, just day-to-day operations that our body has to do in order to, like, stay intact and be able to protect itself from germs and other things. the cortisol actually takes effort away from those things, things like immune function and cell repair and that sort of thing, and directs them toward dealing with whatever a stressful situation is. And because of this, like cortisol is, it's a redistributor. He shows up when stress is going on and it takes energy away from these things and then directs it all toward dealing with stressful situations. But so cortisol, it's good. It plays this sort of broker role in our body when we're encountering stress. And so what I found, and

I learned about this at a research talk about something else altogether was that women who are on hormonal contraceptives, rather than experiencing a big surge in the stress hormone cortisol in response to stressful things, they don't have any increase in cortisol at all. And this is it really surprising because normally when we're feeling stressed out within about five minutes of feeling stressed out, we get this huge surge in this stress hormone. And again, the reason for this is that helps our bodies actually cope with stressful situations. But women on the pill don't have this. So when I learned about this, it surprised me for a lot of reasons. The first reason is just that this isn't normal. Like this isn't, you know, something that we see in otherwise healthy, high-functioning

people. And in fact, this sort of a pattern of like not having a stress hormone response to something stressful is something that we usually only see in the context of chronic stress. So people who have, for example, PTSD or people who, you know, grew up in the context of trauma, those folks tend to not have a stress response in response to stressful situations. And the reason for this is all because of that thing that cortisol does, which is taking away energy from basic bodily functions and directing them towards stress. And so if you're somebody who has been in really chronically stressful situations across your whole lifetime, your body will just shut the stress response down because it needs to do that in order to be able to just do basic bodily maintenance, like repairing your cells and investing in your immune function.

You know, so I learned about this at this conference, and it's, again, it's really surprising because the pattern that we see in women who are on the birth control pill looks a lot like the pattern that we see in people who have undergone chronic stress. And so after I heard about this little research detail that I heard about at this conference, I went into the literature to find out whether or not other people had also found this pattern where, you know, women who are on hormonal contraceptives look a little bit like chronic stress victims when it comes to their stress hormone profile. What I found was that there's been several decades worth of research now that has documented this pattern. So essentially all this stuff was out there before. It was just in these high-level academic papers and people were writing about these studies and they weren't like, hey, we should tell all the doctors about all this stuff

that we found. It's like, nah, let's just go to a conference and give a talk about it, give a couple speeches and go back in the lab. It seems like there's a disconnect there because all of this stuff, all of these hormones, all this stress response, the hormone and receptors are everywhere in our body and everywhere in our brain. And this is not a secret. I mean, this is well documented. It just somehow didn't filter down to the practice level. Right. Well, even more than that, with this set of research results showing that women who are on the birth control pill are lacking this stress response, it mostly had been documented until very recently as a footnote in other studies. So it was like somebody was doing a study on, you know, the effect of early life, low socioeconomic

status on the nature of the stress response, right? And so they do this study, they look at whether they're not a person's childhood environment influences their stress hormone response when they stress them out in the lab. And, oh, by the way, we did the study and we had to throw out all of the women because they were all on the pill and therefore had no stress response. And then they just go on with their results about the effects of early life socioeconomic status. It was just like a footnote. And it's like, hey, you might want to look into that because the fact that they couldn't

even be used in the study because they lack this very necessary bodily process, maybe someone should raise their hand and be like, by the way, this is doing this. Yeah, like, by the way, somebody might care about that. Like, I'd like to know more about that. And that was actually the experience I had at this conference when I first heard about it. And so the speaker was a friend of mine. And I went up and talked to him afterward and said, you know, I stopped listening after you mentioned your little, you know, sort of methodological footnote because that's so important and interesting. And he said, oh, yeah, it is sort of interesting. And it turns out other people have found this too. We found when we went to the literature that people, you know, several researchers

find this effect. And that's when I went into the literature and was really surprised to learn that this is an effect that has been documented now for a very long time. And it's only recently that researchers have begun to really get at why this is. And what's really sort of potentially important for women and for doctors to know is that the picture that's beginning to unfur, fold in terms of the reasons that women who are on the pill have this blunted stress hormone response is because it seems like something in the birth control pill is actually causing women's stress response to go into overdrive. So there was this one paper that came out very recently that was really well executed. They had two very large samples of women and they compared women

who were on the birth control pill with naturally cycling women and they measured several markers of chronic stress. They measured whether or not they had a blunted stress response, which is something that, as I've noted, researchers have been noting with women on the pill for a long time now. But they also looked at other markers, such as whether or not these women had elevated blood sugars and blood triglycerides. Because as I had mentioned earlier, one of the things that cortisol does is it dumps fat and sugar into your bloodstream in case you need to make a fast getaway. And so they looked at whether pill-taking women might have elevated triglycerides and elevated glucose levels. And they also looked at their brains because one thing that we know about chronic stress and chronic sort of cortisol exposure is that it can lead to reduced hippocampal volume.

And your hippocampus is an area of your brain that's really important in terms of learning and memory. And we actually see a lot of hippocampal degradation in diseases like Alzheimer's, for example. where you have these profound and very sad effects on memory. And these researchers were interested in whether or not women who are on the birth control pill might also exhibit some of these other signs of chronic stress, like having reduced hippocampal volume, having elevated blood triglycerides, and also having this blunted stress response. And so they went and they had these two large samples of women,

and that's exactly what they found. They found that women who are on the birth control pill have several biological markers of having experienced chronic stress. And this is something that's, you know, a big deal. And it's a big deal because, I mean, the hippocampal volume thing alone, you know, is potentially very important. I mean, these different measures that they took in the study are things that we tend to see only in people who have experienced like childhood trauma or people who have PTSD. and there are things that we know can be associated with problems with emotion and mood regulation. We know that they can be, you know, associated with problems with learning and memory. And there are some studies now demonstrating that women who are on the birth control pill

may have problems remembering sort of emotionally nuanced events. And this is something that we know that, for example, that cortisol helps our memories do. when we are experiencing the stress hormone cortisol, it helps grab things from our short-term memory and put it into our long-term memory. It's telling our brain, this is important, remember this. And there's been research now indicating that women who are on the birth control pill, if you give them in a really emotional story and you stress them out so they experience a big rise in cortisol, that normally what they find is that women will remember this information better because it's emotional and cortisol is on the scene. And so it filters it right into their long-term.

long-term memories, but they're finding that women who are on the birth control pill don't have this result, right? And this means that women's memories might be impaired in particular when it comes to their emotional memories. And when I think about my own experiences on the birth control pill and just feeling like my life felt flat, I can't help but think that lacking these dynamic changes in the stress hormone cortisol and its ability to sort of allow us to grab on to the emotionally valence things in our environment, both positive and negative. that that might have been at least partially responsible for some of the feelings of just feeling the low-level blas all the time. You're listening to The Jordan Harbinger Show with our guest, Dr. Sarah Hill.

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Subscribing to the show is absolutely free. It just means that you get all of the latest episodes downloaded automatically to your podcast player so you don't miss a single thing. And now back to our show with Dr. Sarah Hill. Yeah, that's horrible, actually, because you don't think, oh, this is going to contribute to problems with my memory, problems with the way that I view my life, the story. arc of my life, kind of, you know, not to put too dramatic a spin on it, but who are we, if not for these, like, events that we remember and feel a certain way about? And if those are all

blunted, I can imagine somebody going, well, if my wedding day and I'm remembering it was like, eh, and my child's birth, and it's like, eh, that's not good for you looking at your future and thinking, but I'm going to have this bright future. It could make you pretty depressed, I think. Well, yeah, no, I think for sure. And, you know, so it was not, like, terribly surprising then, you know, when you look at the patterns of things like, you know, the risk of depression among women who are on the birth control pill, it's not surprising at all when we really consider the fact that in addition to some of the other things that we know that the birth control pill does, in terms of changing what women's sex hormones are doing and changing the activities of some of their neurotransmitter systems, which we might talk about at some point too, but that it's also changing our stress hormone profile in a way that sort of makes us less able to sort of embed our life.

Yeah, it's really not surprising that women sometimes have problems with mood on the birth control pill. I want to talk about some of this reproductive stuff, evolutionary psychology, because I know you have so much interesting material in the book about that as well. So parental investment is higher for women than men, right? We kind of are there for a certain period of time in terms of gestation of the baby, and then she's got nine plus months and then a bunch, what do you call it, the fourth trimester, the first three months of birth, and then, I don't know, the next several years. We found also that children who look more like their fathers tend to get more investment from dad. And I guess that's because, what, if it looks like me, then I'm more certain that it's I don't know. Yeah, no, that's so funny. Yeah. So in the beginning of the book, when I'm really just sort of laying out, like, what is a woman sort of biologically? Like, what does it mean to be a woman? And part of asking that question means, what does that mean to be different from men? Like, why are men and women different from one another? And I address this using, you know, an evolutionary biological perspective, right? And that is that a lot of the differences that we see between men and women ultimately owe themselves to the fact that each one of us has had to solve different sets of

adaptive problems over the course of evolutionary history, right? And so for women, we've had to solve some adaptive challenges or some, you know, sort of survival and reproductive challenges that have to do with being the sex that has to invest a minimum of nine months in pregnancy, right? And this is the reason, for example, that we see that women tend to be sort of more cautious in terms of sexual partners than our men, right? Because the costs of making a bad mating decision, especially historically before we had contraception, and were much more steep for women than they are from men. And to get to this issue that you were talking about with the faces of babies as being evaluated by men, one set of adaptive challenges that men have had to solve over the course of evolutionary

history that women have not has been this problem of what's known as paternity uncertainty. And it's just this idea that any time a woman has a baby, she knows for certain that it's related to her. No woman has ever had a child and looked at it and thought, I don't know. I don't know, Jim. Yeah. Yeah. What have you been? Jim's like, yeah. Like, what have you been up to for the last, you know, a couple of years? But for men, you know, there's always a chance that when your partner has a child, that it's not actually yours. And all of this means is that for men and women, there's been sort of differences in the degree to which evolution by selection has penalized sort of unmitigated love and care of children.

Right. So for women who are investing really heavily in any child that that is theirs, evolution by selection has never penalized that. That is, it's never been costly for women to invest, you know, like crazy and just like, do all the jimbery classes and spend all their time with this baby and, you know, do all of those things. Like there's no selection that has never penalized that because it's always a woman taking her energies and investing them in a genetic relative, right?

and those are the types of things that tend to get rewarded in terms of gene transmission, which is ultimately how traits get inherited and how the process of evolution by selection works. For men, however, men, you know, would have been penalized in some cases if they just sort of through unmitigated love, devotion, and resources toward any child that their partner has. I mean, this, of course, is because there's always a chance any child that a man's partner has isn't actually biologically his, right? there's always the possibility that it might, you know, actually belong to somebody else.

Because of this, just because this is a possibility, not saying that this happens with terrible, alarming frequency, but because this is something that sometimes has happened over the course of evolutionary history, men have been favored by the process of selection, not to just, like, dump all of their resources with wild abandon into any child that's theirs, but instead to just sort of be sensitive to cues of relatedness. So, you know, some cues that, men might use as a means of assessing relatedness to a biological child of theirs is the behavior of their partner, right? Is there a partner somebody who has a reputation of not being faithful? If so, maybe they would invest less in a child that she has because, you know, there's a higher

probability that the child is not biologically related to him, given his partner's past behavior. Another cue is the actual physical appearance of the child. I mean, this is the research that you were alluding to. And this is this idea that men may sort of unconsciously cue into physical similarity between themselves and their children and then may invest more heavily in children that are more certainly related to themselves. So children who look phenotypically more similar to themselves, they may invest more heavily in than children who do not phenotypically resemble them. And there's been a couple of different studies now that have found this to be true, whether looking at it cross-sectionally and actually looking at dads and moms and then their physical resemblance to their children.

And these studies find that fathers and children report more emotional closeness to one another when they resemble each other more than they do when they resemble each other less and that you don't find this pattern for moms and their children. But they've also done it experimentally where they've actually taken faces of babies and then more. morphed in like his own face into the face of the baby and then shown, you know, men, these pictures of these babies and then asking them, which one would you like to adopt, which one would you like to invest in and so on and so forth? And men overwhelmingly favor the baby that has had their own face morphed into the photograph. So the baby kind of looks like

them. Whereas women don't show that same bias. Women are, they sort of pick at random, which baby they like the best, which just goes to show that men's brains are kind of key. in to sort of similarity in the face of children and that this might sort of allow them to sort of let off the brakes in terms of investment, investing more heavily in children that are more certainly theirs. Yeah. Wow. This is interesting. Another fascinating little tidbit was that men's testosterone levels go up and down in these seemingly fickle ways. So you mentioned that if we see some women or our team wins in sports or politics or we're around weapons, that our testosterone levels go up and that's funny. I'm thinking like, okay, so on the way out next time I'm going to vote,

watch a basketball game, and then polish my rifle. I don't know. Yeah, exactly. And the girls would be like, hmm, there's something about him. Right. Exactly. Yeah, stop by the strip club and then polish the rifles. I don't know, you got to work the women in there somehow. Yeah, it seems really funny because it's so obvious somehow, right? It's such a blunt instrument seemingly. Like, oh, you guys are so simple. All you need to do is see some women, go see a sports game, or beat someone some other way and then, like, shoot something. I mean, that just checks out at every level. Well, it's so funny because, you know, women are always pegged as being sort of the fickle, unpredictable ones because our sex hormones change cyclically. And women's sex hormones do change cyclically when they're naturally cycling

with estrogen being the dominant sex hormone in the first half of the cycle. So usually, you know, between days zero and day 14 or so, estrogen is dominant, and then at the second half of the cycle, progesterone is dominant. And so we always get, you know, historically, we were treated very badly because it was seen that you couldn't predict what women were going to do because our sex hormones were changing all the time. But the point with testosterone that I make in the book is like, you know, women's sex hormones do change cyclically, but they're not capricious and fickle at all. They're actually incredibly predictable. And if you tell me a woman's age, and the first day of her last menstrual cycle,

I can predict with a remarkable degree of accuracy exactly what's going on with her sex hormones. But for men, with testosterone, it's like a totally different, you know, it's a totally different ballgame, right? It's like the Wild West. Men's testosterone levels change all the time. And like you were saying,

they change if you see a beautiful woman. They'll increase. They'll increase after a sports win. It'll decrease after a sports loss. It'll increase after your team wins. It'll decrease after your team loses. If your political candidate wins, it'll go up, and it also changes in response to being partnered and having children.

In both of those contexts, it actually decreases, right? And we tend to think about our changing sex hormones as being something that makes us, you know, irrational and fickle. And we can kind of laugh about it, you know, when we think about these things with men and, and, yeah, in the presence of guns. But the idea that our sex hormones are responding dynamically to, for women, you know, these internal cues of conception risk. And with men, in response to things that sort of increase or decrease the benefits that are associated with investing effort and mating related pursuits, I mean, our hormones are brilliant, and they actually lead us to behave in these ways that are really functional, given, you know, our environmental

and our bodily context. And so with men, you know, their testosterone, for example, it decreases when they have children and when they get married, because those are contexts in which it is not beneficial to most men to be, like, distracted by how attractive their next-door neighbor is. Right? During those times, they need to be reading Good Night Moon and changing diapers, or they need to be helping, you know, make their partner happy if they're trying to maintain the integrity of their long-term pair bond. And so as our sex hormones change, and both men and women have sex hormones that change, as they change, they do change what we think, feel, and do. But this is a good thing. It's not a bad thing. It doesn't make us sort of,

capricious and whimsical. It allows us to better adapt to our environments and to be able to meet each one of our evolutionary endpoints in a really coordinated, really smart way. Can you give us a little bit of an overview of how during different times in a woman's cycle, she's looking for different qualities in men? And also, of course, how that changes mate preference, because if you're messing with that, now you're messing with your mate preferences, and then suddenly you go off the pill because you want to have kids and it's like, what the hell? Yeah, exactly. It's like, what What did I do? What did I do?

I've made a terrible mistake. Yeah, exactly. So women's sex hormones is really fascinating. And this is something that researchers have really kind of dived into over the last couple of decades. And this is just that idea that women, during the first half of the ovulatory cycle or the menstrual cycle, you know, this is when an egg is beginning to mature and this is all the stuff we learned in health class.

As the, you know, egg follicles are being stimulated and there is an egg that's growing and maturing. this process leads to the release of relatively high levels of estrogen. And estrogen increases, you know, as a woman nears closer to ovulation. And just as a reminder, ovulation is when a woman's body releases an egg that can then, of course, be fertilized and, you know, turn into a baby. And this is, of course, something that evolution by selection has worked really closely with, given that, you know, the whole process is driven by the act of

production and gene transmission. And so during times in the cycle when estrogen is relatively high, so this is during those times prior to ovulation, in particular, you know, right near ovulation. So like five or so days prior to ovulation, which is known as the peri-ovulatory phase of the cycle, this is when estrogen levels are relatively high. Okay, so this is when your body is gearing up for the possibility of conception. And so this is, you know, the sex hormone estrogen actually cues a whole string of events in our brain that are basically getting women ready to have sex with a potentially really high-quality partner because this is the time in the cycle when conception is possible. And so what the research finds, what it predicted, I guess first, and then, of course, what they

have found once they've collected data is that given that estrogen levels are relatively high at points in the cycle when conception risk is high, we should expect that, A, it should increase women's sort of desire for sex, right, because an egg isn't going to be able to fertilize itself, right? And so women should sort of be really attuned to activities that might get sperm within proximity of the egg. And so women should sort of be more. That was a very diplomatic way of putting it, yeah. Yeah, that's what I used to tell my mom, yeah, when I was about to go out and it would usually keep me from having to be home early. But it's like if, Wait, you told your mom, I'm ovulating, so I need to go and increase activities that, wait, what did you tell your mom?

You might just, like, want to cut that part from the yard. I think we're leaving that in. You're going to leave in my, yeah, like my scientific jargon that I was trying to use to put myself out of an early curfew. And then my mom would be like, no, Sarah, that's disgusting. Right. Disgusting. You're coming home early and change your clothes. Right.

You're not wearing that. Yeah, exactly. Yeah. So, you know, during points in the cycle when conception is possible, estrogen is relatively high, and it increases women's desire for sex. It increases their sort of attunement to men generally. So women sort of notice men more when estrogen is relatively high. And at this time, when estrogen is high, women are also really sort of attuned to what I'm going to call sexiness cues. So at high fertility, women tend to sort of place a greater emphasis on,

cues that historically have been associated with the sex hormone testosterone in men. So things like a man with a deep voice, like a relatively deeper set eyes, a square jaw, broad shoulders, social dominance. Those types of cues are found sort of particularly sexy to women at high fertility when estrogen is high relative to other points in the cycle. And there's been some really neat research where they've actually looked at a woman's own estrogen levels across the cycle and how that predicts their preference for testosterone markers in men. And what you can find is that, or what you see with this research, is that estrogen levels predict the testosterone levels that women prefer in men and just basically, you know,

showing that estrogen really, you know, likes these sort of manly cues in men. And the idea behind this is that testosterone is believed to be a quote unquote good genes marker. And what this means is just that testosterone has been historically linked to having a relatively low mutation load and having a relatively good immune system. And the idea behind this is just that testosterone is a known immune suppressive. So if you like take exogenous testosterone, so guys who are taking steroids, for example, it actually suppresses the activities of your immune system. And naturally, your body will not allow itself to produce copious amounts of testosterone unless its immune system can handle it. Right? And so this is one of the reasons that testosterone is sort of linked to high genetic quality or believed to be, you know, sort of a cue to high genetic quality is just because only a man who has a relatively good immune system, only his body is going to be producing copious amounts of testosterone because he's the only one who really afford it immunologically. And so what

the research finds is that at high fertility, women tend to have a heightened preference for these sort of cues to masculinity and sexiness and their partners, and that this sort of goes away once estrogen is no longer the dominant sex hormone. And so with the birth control pill, of course, what the birth control pill does is it suppresses women's own levels of sex hormones. So it keeps estrogen and progesterone relatively low. And every day you're taking this pill that has a relatively high level of synthetic progesterone or progestin's relative to estrogen. And so what this means is that when you're taking the birth control pill, you're basically kept in a consistent state of progesterone or progestin, in this case, dominance. So you're never having that opportunity

for estrogen to kind of take over the reins and sort of cue into these types of testosterone markers. And so what researchers predicted might happen to women on the birth control pill is that they might actually exhibit a preference for less masculine men relative to what is observed among, naturally cycling women. And so researchers have gone out and tested this, both by looking at the preferences for male faces of pill-taking compared to non-pill-taking women, but also looking at the faces of partners that were chosen by women who are either on or off of the birth control pill. And in both cases, what they found is that women who are on the birth control pill, not only do they prefer a less masculine male face. And this is true whether they're not. They're

choosing this face as a short-term sexual partner or a long-term committed romantic partner. But they also seem to be choosing as partners men with less masculine faces. So when they compared the faces of partners who were chosen by a large sample of women who are on the birth control pill compared to a large sample of women who were naturally cycling, the faces of the naturally cycling women's partners were more masculine than those of the birth control pill taking women's partners. So what does this do then to our long-term versus short-term mating strategies? What does it do to women's mating strategies, right? Because as a guy, I can't really do much about that.

But of course, I mean, maybe you can let your 5 o'clock shadow out a little bit, you know. But like, what does this do? Because it seems like then, okay, great, I'm on the pill. I'm looking for this nice, less masculine guy because that's what the pill's telling my brain it wants. I get married. I want to have a baby. I go off the pill and I'm like, where are your cheekbones, man? Where's your jawline?

What happened? You don't look like the guy who's dating in college. What was I thinking, right? Hopefully you find out earlier or hopefully you can adapt, but it seems like kind of dangerous. Not good for your marriage. Good for spreading genes, though. Well, this is like super provocative.

So this is a result that is like brain Velcro because once you start thinking about it, it's hard to stop thinking about it, at least, you know, it was for me when I first was learning about this research because it really is sort of provocative when we think about the idea that the birth control pill might be shaping these, you know, sort of big relationship dynamics is pretty interesting stuff. And there has been research looking at

what happens when women are on the birth control pill, choose a partner, and then go off of it, right? That's sort of like the $8 million question. And in one of the best executed sort of versions of this research, and what researchers did is they actually followed married couples over time. So they did a longitudinal study of married couples, and then they wanted to see what happens with the women in their sample who were on the birth control pill when they chose their partner, what happens at such a point if they go off of it? And how does it change their sexual satisfaction? And how does it change their relationship satisfaction? And what they found was that going off of the birth control pill for this sample of women did change their sexual and relationship satisfaction. But whether it got

better or worse, depended on how hot their partner was. And so women who were partnered to attractive men, they actually reported an increase in sexual satisfaction and relationship satisfaction after going off of the birth control pill. But if they were partnered to somebody who is not attractive, they found the opposite. They actually felt worse about their sex life and they felt worse about their partner in sort of the big picture of their relationship even, right? And this is potentially, you know, it's not anything to get alarmed about. I don't want women to be who are listening to this.

And they chose their partner when they were on the birth control pill to run out and find a, get a good lawyer on retainer. No, it's the guys who are like, crap, I've got to start spiking my wife's pumpkin spice lattes with the birth control pill or our marriage is over. The guys are more worried, I think, right now. Right. Yeah. Well, you know, so what the follow-up research says is for those people who are really, you know, sort of feeling worried, is that the sort of relationship between all of these variables. so the relationship between your pill status at the time you choose your partner and then how attractive your partner is and how that changes your relationship satisfaction over time. All of this stuff seems to be

incredibly complicated and seems to be influenced by a number of factors, including sort of what your pre-birth control pill level of hormones was. So how different is the birth control pill making you from the version of yourself that you were before you were on it? But also the relationship dynamics. So there's some really cool work in non-human primates. So this is something that hasn't yet been tested in humans. I'm hoping that this gets done soon. Maybe we'll do something like this in my own lab. But what they find is that the way that the birth control pill, either being going on it when you were previously off it or going off of it when you were previously on it, the way that this influences the relationship dynamics with your existing partners seems to be very much influenced by the quality

of the relationship. And so the quality of the relationship is also something that's probably going to be paramount here. And so looking at the complex dynamics between like how attractive your partner is, the quality of the relationship, were you on the pill, were you off of it, what was your level of sex hormones at this time, what is it at this time? It's all very complex and nuanced. We can't make really good predictions yet about who's going to respond what way to what formulation of the pill and with what quality of relationship. But this is just information for women to have to either about. understand their own relationship dynamics, or if you're a woman who, you know, is on the birth

control pill just because you, it's procedural inertia, right? You've been on it because you were in a sexual relationship. You're not in one right now, but you're hoping to find a long-term partner. I mean, my recommendation to that woman might be, hey, if you don't need the birth control pill right now and you're looking for a partner, like maybe you go off it for a little while. maybe you let your naturally cycling hormones have a say in who you're attracted to right now, because it could matter in the long term. We just don't yet know. The research isn't at a spot where we can really, you know, make a prognosis about what

people's relationships are going to look like on and off the birth control pill. But it's something that's really worth, I think, taking into consideration as we sort of, you know, move forward when we're thinking about partner choice. So maybe, and again, the science is the jury's still out, but choose long-term partners went off the pill and short term probably use the pill because getting pregnant by the wrong guy trumps pretty much anything else that we might be discussing here. Oh yeah, no, absolutely. And even with anything that I talk about in my book, and I try to make sure that I mention this frequently, is like, no matter what problem it is that I'm telling readers about, like in terms of things that could

potentially sort of go wrong when they're on the birth control pill, almost none of those, I mean, I can't think of a single one of those outcomes that's worse than being barefoot and pregnant at 17. Like, it's like just to put everything into perspective. Not getting pregnant at the wrong time is such a big deal that needs to really factor heavily into women's minds when they're making these decisions. Because I do think that we take birth control for granted and we kind of forget that, you know, without the ability to safely regulate our fertility, our lives would be much worse. You're listening to the Jordan Harbinger show with our guest, Dr. Sarah Hill.

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And now for the conclusion of our episode with Dr. Sarah Hill. Yeah, it's seriously problematic. And you do a good job in the book of explaining how the pill is essentially unlocked all this human capital. I mean, you're a psychologist. So you probably, it's hard to say whether you'd have made it all the way through your studies if you were worried about getting pregnant all the time. You'd have had certainly a different social life, I would imagine, during that period of time, not to highlight. That's a nice way of saying that, Jordan. Yes.

You know, I'm making an assumption here. But there's a lot of women that want careers and they also want to have a significant other. and it's kind of tricky to have both. I mean, imagine going to medical school and you're in year nine, and then you're like, well, got to drop out. I mean, that's terrible. Yeah, no, it is terrible.

And it's like, you know, more than anything, the birth control pill, what's been so amazing about it is it has allowed women for the first time in history to plan. And it's like most of us won't begin doing something that takes a long time, like going and getting a medical degree or getting a PhD or going to law school, unless we feel pretty certain

that we're going to be able to complete whatever it is that we're doing. And having the birth control pill and just, you know, having the ability to safely and really effectively regulate our fertility has been an absolute game changer for women. And you see this when you look at the rates of women who are applying to advanced degree programs, you see that after the birth control pill became legally available to women who were single, like back in about 1970, you see that women's applications to post-secondary education and to advanced degree programs like medical schools. and law schools went from being only 10% of applicants to 50% of applicants. Wow. It's really allowed women to dream bigger and do more. And you're right. Like in so doing, it's opened up all of this new capital. You know, some of the most brilliant women that I know, I don't think that they would be doing the things that they're doing.

I mean, some of these women are doing things like coming up with revolutionary treatments for cancer or coming up with revolutionary, you know, new ideas for the prevention of Alzheimer's disease. And I think about the fact that, you know, there is a time in our history before we had access to safe, really effective modes of fertility regulation that these women wouldn't be doing these things and how much better we are as a society for having something like this and being able to regulate our fertility and opening up the, you know, doors for these really brilliant women to be able to make our world better. It's amazing. I want to go back to some of the different ways that being on and off cycle, the fertility cycle affect preferences, because this stuff is just so dang interesting. So one takeaway here, women see other ovulating women at high fertility and often won't like that their men are interacting with her. I mean, how fascinating is this, right?

So this is an unconscious process. And of course, my takeaway from this as a guy, well, as a, I don't know, as a guy who probably should take other things away from this. But it's like, okay, so if we want to meet some women on the prow, we bring another woman who we know as a thing for us, we wait for her to get jealous. We have ovulation radar, right? Right. Yeah, no, it is so fascinating.

Like, both men and women seem to be able to pick up on another woman's fertility status. And the exact mechanisms through which this is going on are probably multifaceted because we know, for example, that men prefer the scent of women at high fertility compared to low fertility. So there's probably some scent-based queuing. We know, like, when you have men and women looking at faces and partial body shots of, you know, ovulating and non-ovulating women. that both men and women seem to be able to detect fertility and not like in a way where they're asking, like, is this person fertile? But rather, like, how attractive is this person?

And men tend to find women, you know, their faces and bodies more attractive when those women are at high fertility compared to those exact same women when they're at low fertility. And women, as you mentioned, they tend to find women more threatening when these women are at high fertility

compared to low fertility. And their jealousy tends to increase. So they feel more jealous if their partner is interacting or even if they just imagine their partner interacting with somebody who's at high fertility compared to low fertility. So all of us seems to have the ability to pick up on these subtle cues to estrogen presence and to high fertility. You know, who knows?

Maybe the birth control pill, right, because it's suppressing estrogen and suppressing women's fertility. Like maybe we're going to have this whole new era of female friendship. right, where women aren't going to be feeling threatened by other women. And so maybe it's going to actually facilitate more female friendship, you know, stay tuned. Yeah, catiness is down globally. Man, there's so many fascinating things. Tell me about strippers and tipping during their cycle and while on the pill.

This was just like, who studied this? That's what I want to know. Yeah, I know. You're like, and why was I not working in that research lab? Like my whole time in college. Can you imagine asking for funding for this? So what we want to know is, and they're just like, yeah, yeah, yeah, we get it. you have 10 year. Here's money.

Yeah, exactly. Yeah, it's like, exactly. We will fund this and here's some singles. Go have fun, gentlemen. Thanks. Yeah, your grant will be funded in singles. I might need to come and observe this laboratory during this particular experiment. I can see all of like the old guys being like, this is very curious. Let's go as a group.

Yes, yes, we have to go inspect and make sure that their research methods are above the board. Yes, gentlemen. That's right. Yeah, I want to make sure that this is all properly. documented double-blind. I was like, excuse me, could you show me to the champagne room, please? I'm doing research. Yes.

So this study is just so fun. And it's a study that it's fun and it's also really clever. And it's clever because one problem that we tend to have in science, and this is particularly true in psychology, because human behavior, it's like we say one thing and we do another all the time. I mean, we're just, people are hypocritical. And it's because, of course, you know, we don't always know why we're doing the things that we're doing and we also don't always necessarily like to say what we're going to do.

We just, you know, it's always better as a researcher to be able to get sort of non-reactive measures. So just measuring people behaving in the wild and then using that as a means of understanding their psychological state. And that was what these researchers did with the sort of infamous lap dancer study. And so in this study, what the researchers were really interested in was whether or not men can pick up on these subtle cues to fertility, right? And so do men tend to reward women more when fertility is high, so when estrogen is high across the cycle, compared to when fertility is low? And then do we not observe the same type of a thing, of course, across the cycle when we're looking at women on the birth control pill, because women on the birth control pill are, of course,

chronically infertile, right? Estrogen never increases across the cycle. It's kept relatively low across the board. And so what was really clever about the study was that the researchers were able to quantify men's sort of interest in women by studying the tip earnings by these exotic dancers or these strippers. And so what they did is they had strippers in a club or, you know, the club, quote unquote, the club. They had the strippers make note of A whether or not they were on the birth control pill or whether they were naturally cycling. And then they just had to keep a diary over the course of a month of their tip earnings. And they also had to make note of when they got their period. Because you can actually, if a woman reports when she gets her period, you can make some

pretty good estimates of what her fertility status is and what her hormone status is just using that information alone. Because starting from like ground zero, which is the day that a woman gets her period, usually starting about, you know, three to five days afterward, you're going to begin to see estrogen levels begin to creep up. And then they start to really increase right around day 9, 10, 11, 12 is when estrogen tends to be really high because that's when ovulation is getting ready to occur and that's when conception is possible. And then it starts to decrease. And so what these researchers wanted to know was during the times when estrogen is relatively high and conception risk is high, are women actually earning more money? Do men find them more attractive

and are giving them more tip earnings when fertility is high compared to when it is low? And then is this sort of mid-cycle increase in tip earnings that was predicted? Is it suppressed in the pill-taking dancers? Like, do pill-taking dancers earn sort of a more steady income across the cycle? I'm not having this big, you know, predicted increase in tip earnings when estrogen is high. So the women in the club They kept track of when they got their period, and then they kept track of what their tip earnings were. And what the researchers found was that, lo and behold, the naturally cycling women were, in fact, earning a significantly greater amount of money at high fertility compared to low fertility. So they were earning the most money. They were getting the most bang for their buck when estrogen levels were really high.

And women who were on the birth control pill, on the other hand, they had relatively stable tip earnings across the month. then they never reached that peak that were reached by the naturally cycling women. And so, you know, there's a couple of takeaways here. Yeah. Right? One is that men seem to be able to pick up on cues to estrogen's presence and to fertility and that they find women most desirable, whether it's, you know, the women are dancing particularly sexy at this point in time, whether their bodies look particularly good,

whether they smell particularly good. You know, we don't know any of that from this study. they didn't really get down to the nitty gritty and like, what is it exactly that's changing at high fertility that's making these women more desirable to men at this time compared to other points in the cycle. So we don't know exactly what the mechanism is, but the women at high fertility were earning more money than the same women were earning at points in the cycle when fertility was low and when estrogen was low. Whereas the poor pill takers, those poor pill-taking women, they never reached that apex of earnings. And so their overall tip earnings across the cycle were relatively lower than the naturally cycling women.

And the naturally cycling women were really benefiting from the rise in estrogen that was occurring mid-cycle right near ovulation. I heard that even the voice and face is judged more attractive during the fertile phase. So is that a health indicator? Is that, okay, they seem healthier because their voice in face is judged more attractive because of where they are in their cycle? Yeah, well, it's not so much health per se as it is fertility, right? Because essentially what everybody is picking up on is like conception risk. Gotcha. And that, you know, and men, of course, have been wired by evolution by selection to just zero in on qualities that historically have been linked with conception risk.

Because by doing so, of course, you know, men historically who were most attracted to women when they were able to conceive, those men would have probably passed down that preference for those qualities to a greater number of descendants than men who had alternative preferences. And so, yeah, men and women, both, if they're evaluating, like, the voice of women, for example, they find their voices more attractive sounding when those women are at high fertility compared to when they're at relatively low fertility. And interestingly, I have to tell you this, because I've been, like, dying to share this with anybody who will listen. Sure. Because I got an email from a vocal coach. And what she found is that her soprano's If they go on the birth control pill because it suppresses estrogen, it actually suppresses their

ability to hit the highest notes. What? Wow. Isn't that wild. Yeah. And this just goes to show you that women's voices, you know, are influenced by estrogen presence. And that women's voices, they do get a little bit higher at high fertility compared to low fertility

in the cycle. And when you suppress women's levels of sex hormones, including estrogen, and are really, really big way that it actually can change the quality of their voice. I just thought that was the most fascinating thing that the birth control pill might influence your ability to sing soprano. Man, that's incredible. And it shows you just how pervasive, is pervasive the right word, how this just changes everything about your body in sort of one fell. Did you say this in your book? It's like dropping a bomb on a house to try to put out a candle. Like it'll do the job, but a lot of other stuff is going to get messed up in the process. Yeah, yeah.

Yeah, that's totally what I wrote in my book. Yeah, exactly. It's like it'll do what you want it to do, but it's like not targeted, you know, because we take it for these targeted effects, but it influences everything. And the reason for this is that because pregnancy and, you know, in conception, because it's required a workaround by just about every single system in our body, almost every single system in our body is sensitive to changes in sex hormones. I'm really looking forward to the next, you know, several decades of research. where we look at the impact of the birth control pill, even on things like a woman's gate, because we know that the way a woman walks is influenced by fluctuating sex hormones. So does the way that women sort of carry themselves change when they're on the birth control versus not? So fascinating. The book has so many different ideas in here that were new for me, especially, I mean, one of the questions was, why do women have periods in the first place? Because not every primate, or is it primates or not every animal certainly does this? Does every primate do this? No, no. So humans are really unique in having a period. Periods are a weird thing, you know, and they're weird because they're really metabolically costly. So, you know, historically, calories were hard to come by, right? Like there wasn't a Taco Bell in every corner like there is right now, right? And so because of that, you know, for most of our evolutionary history, you know, we were living relatively subsistence level, you know, resources were relatively unpredictable. So our bodies are actually optimized.

for those types of environments, which is why, of course, we still like things that are sweet and fatty, even though, you know, they make us fat, but happy. Dopamine. Yeah, so, you know, our bodies are optimized for environments that are relatively resource scarce. And so the idea of having this, you know, period where we're shedding this endometrial lining

when we could just reabsorb it into our body, like, which is what most animal species do, by the way, the endometrium just gets reabsorbed. so that way the body can recycle the materials that it used to create that to make a new one. But we get rid of it. And so it's like sort of this evolutionary question mark for a really long time where researchers couldn't really get a handle on why it is that women would have a period at all. And so not all that long ago, probably in the last 20 years or so, researchers had begun to put forth this idea that the reason that women shed their endometrial lining

and the monthly nuisance that is having our periods, has everything to do with the fact that there's a competing interest between a mother and a fertilized egg in terms of whether or not that fertilized egg should become a pregnancy. Pregnancy, of course, for human females is something that's incredibly costly.

So for mothers, for human women, they should be really choosy about what embryos they allow to implant and actually turn into a pregnancy. But now, in the eyes of a fertilized egg, it should always turn into a pregnancy, right? Because any fertilized egg, this is its one shot at life. But from the eyes of the mother, of course, this isn't a very good deal, right? Mother should be very picky and should screen embryos for their probability of being able to turn

into a successful pregnancy. So what researchers have hypothesized is that the endometrial lining, it plays a role in the screening process, right? The endometrial lining, rather than being something that facilitates conception or makes conception easier for an embryo, it actually is really difficult to get through. It's densely packed with cells that are very difficult for a fertilized egg to be able to wiggle through and actually be able to implant itself on the wall of the uterus. This is like the first screening mechanism that women's bodies have in order to sort of make the quote-unquote decision, right, about whether or not to invest in this fertilized egg. And if the fertilized egg can't

make it through, then it just goes out when the endometrial lining sheds. That fertilized egg will just go out with the whole nuisance that is your period. So that's like the first level of screening. But there's also other screening mechanisms that kind of go on in women's bodies that sort of allow them to test whether or not this is potentially going to be a healthy pregnancy. and if the fertilized egg isn't releasing these types of factors that are associated with healthy pregnancies, the endometrial lining will get shed and then the fertilized egg will sort of make its way outside the body. And so basically the period is something and the shedding of the endometrial lining is something that occurs to allow women to pull the trigger on getting rid of any pregnancies that they don't want to be having.

And again, when I say don't want to be having, I don't mean this in the way like a woman, thinking I would like to be pregnant right now or not like to be pregnant right now, but just rather that the body is making a decision about whether or not this seems like it's going to be a healthy pregnancy or not. Right. So it's expensive, but it's less expensive than having all these resources diverted towards a non-viable fetus and then dealing with that for however long that lasts. Yes, yes.

No, absolutely. A lot of people are probably wondering why I'm doing this whole show on the birth control pill, but I'm doing this because I want women and those of us that love them to stop. Stop thinking something might be wrong with them when maybe there's something wrong with their medication. And so I'd like to leave everyone with some advice here because first of all, the depression thing with the pill is so real.

So if you're going on the pill, you advise to tell those close to us that we're going on the pill, maybe look for some signs of depression. If I change who I seem like I've been for the last X number of years, let me know. Because when you're on the pill, you might just think, oh, my life's getting crappier.

I'm getting older. I'm losing interest in my partner. that's totally natural. So what if I have a psychotic episode every now and again? Like all these things, you just sort of shrug it off, especially if you don't know that it might be caused by the birth control pill. Yeah, no, absolutely. I think that, you know, for a very long time, just because we all have had a little bit of a blind spot when it comes to everything that the birth control pill can do, that we tend to, when something doesn't feel right when we go on the birth control pill, that we tend to internalize it and we tend to blame ourselves, right? And like you said,

that we think, oh, well, my life is just getting worse or school is harder or my boyfriend is just more annoying and so I'm not interested in him anymore. And women's doctors for a long time, and it is still the case with some women's doctors, sort of reinforce this by telling women that, no, I have not read about this in my 25 minutes of training on the birth control pill. And so this isn't real. If a woman is going on the birth control pill, yes, absolutely. Tell your friends. Tell a part keep track of it yourself in a journal. I really recommend sort of keeping track of, you know, who you are, what your sort of motivational state is when it comes to things in your life that are important to you in a journal. So that way you are able to sort of have a trail of breadcrumbs

back to yourself. If you go on the birth control pill and you find that you're experiencing changes in motivation or changes in mood. What if we're already on the pill? How can we assess whether or not our mood has changed if we've already started taking it? Right, and that's a really great question. And, you know, it's one of those things where you can sort of talk, you can do sort of post-mortem interviews, right? You can talk to people that you knew before you were on it. But even more than that, I think that keeping a journal and keeping track of how you're doing in the areas of life, especially those areas of life that I kind of detail in the book that we already know the birth control pill can influence, just if you keep a journal and sort of keep track of how you're doing in these different areas and how you're feeling about life. Most of us, when things are going well for us, we should have more good days than we have bad days. And if you're not having more good days than bad days and things in your life are going well, I would recommend talking to your doctor. Does it make sense to take a break from the pill so we actually get to know ourselves off of it? Because I think if we've

been taking it for five, ten years, you might not even know who you are underneath the hormonal blanket that you've got on. I think for women who are able to safely do this, I always feel nervous making this recommendation just because I would absolutely hate to have, you know, somebody who's not protecting themselves from pregnancy in some other way do this. Sure. And then end up with an unwanted pregnancy, which I think it would be a really bad outcome. As long as you're protecting yourself from pregnancy in some other way, I think that it's a good idea to take a break and see who you are.

Is it safe to say that if you're not having sex and you don't have other medical reasons to be on it, maybe you should talk to your doctor about getting off of it? It certainly couldn't hurt, right? I don't think that it could hurt. I think that if you aren't sexually active and you're on it for some other reason, that it might not be a terrible idea to figure out who you are in the absence of the birth control pill. And give it a couple of cycles because when you go off of the birth control pill, it does throw you into a little bit of a hormonal tailspin.

You know, if you're getting that same hormonal message every single day for years, and then all of a sudden you take it away and then your body's having to figure out ovulation again, it's going to take a little bit of time, and it can be a little bit of a disruptive period for women. You know, I mentioned I'm writing a book about the birth control pill, and everybody has a story or a friend with a story. And so I've gotten to talk to a lot of women, and some of the things that I've heard from women in terms of big changes, like when they were choosing a spouse or they were choosing a career path, and then how it changed. They're sort of feeling at home in their own life changed. after they went off of the birth control pill, it really sort of opened my eyes to, you know,

for me, it was like I felt like I woke up, but for some of these women, they felt like they woke up, and then all of a sudden they don't like the choices that they'd been making. It was a really eye-opening prospect to me, and so I do think that you're right, if you're in a period in your life or you're making important, lasting decisions,

that it might not be the worst decision in the world to make those decisions off of hormonal influence and under the influence of your own naturally, recycling hormones. Dr. Hill, thank you so much. This has been awesome. Super fascinating. I loved the book. I highly recommend it. We'll link to it in the show notes. Thanks for spending so much time here with us today. And the book has a lot of other anecdotes that are equally fascinating, surprising, shocking. So we didn't even cover everything today, of course. So I, again, I highly recommend this. Thank you very much for your time. Thank you so much.

Great show, Dr. Sarah Hill. This is your brain on birth control, the surprising science of women, hormones and the law of unintended consequences. That's the name of the book. Of course, we'll link to it in the show notes as we always do. Great big thank you to Dr. Sarah Hill for coming out for that. By the way, there's workshets for this episode. You can review what you've learned from Dr. Sarah Hill that's at Jordan Harbinger.com in the show notes. And also in the show notes, we've got transcripts, which we have for this episode and every episode, and those can be found in the show notes as well. I'm teaching you how to connect with great people and manage relationships using systems, using tiny habits.

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