Speaker 1: Hello, and welcome to Deeply Human, the show about why
Speaker 1: you do what you do. It's general admission, so sit
Speaker 1: anywhere you like, but if you sit on top of
Speaker 1: someone else, you must have their express consent. I am
Speaker 1: your host, DSSA, and I've got an unusually sexy program
Speaker 1: queued up this time around, So if you are in
Speaker 1: the company of pint sized listeners who don't yet know
Speaker 1: how they got made, this program might let the reproductive
Speaker 1: cat out of the bag. Today we're tackling the question
Speaker 1: why do you have sex all the time? Now, those
Speaker 1: of you who are seated alone maybe thinking, lady, you
Speaker 1: are mistaken because I am definitely not having sex all
Speaker 1: the time. And those of you sitting with the date
Speaker 1: might be thinking that's obvious. We have sex because it
Speaker 1: feels good. But I assure you that is only half
Speaker 1: the story. You are in for an evening of evolution,
Speaker 1: wonder and Victorian perversions. We're about to find find out
Speaker 1: why humans have sex at times that our fellow mammals don't.
Speaker 1: Let the show begin. My name is Steve Gangstead. I
Speaker 1: am a professor of psychology at the University in New Mexico,
Speaker 1: and I study sex. I study sexual interests. I study
Speaker 1: hormone influences on sex. Perfect, I'm interested in sex. Okay.
Speaker 1: To understand the quirks of human sex, we first need
Speaker 1: to know how it works for most mammals. Here's Steve
Speaker 1: giving us the lay of the land. Okay, let's just
Speaker 1: call it like it is. Yes, a show about sex
Speaker 1: is going to have a lot of unintentional dad puns.
Speaker 1: There will be double and triple entendres. But I'm just
Speaker 1: gonna ask that we call on our better angels and
Speaker 1: take the high road. Okay, Steve, please tell us about
Speaker 1: mammal sex. So, for most female ammalst it's two or
Speaker 1: three days out of a cycle that they have sex,
Speaker 1: and otherwise they're not willing to have sex with males
Speaker 1: that initiated, and they're really not that attractive to males either.
Speaker 1: Males seem to know. And why would most mammals schedule
Speaker 1: their whole sex life into just a couple of days
Speaker 1: of the cycle. Well, sex takes time and energy and
Speaker 1: even risks injury. Most female mammals are only into it
Speaker 1: during the fertile phase. But how do the males know
Speaker 1: when those days are? Well? In? In some species, like
Speaker 1: particularly some of our close relatives in the primate order,
Speaker 1: females have sexual swellings. They have these swellings on their
Speaker 1: rumps that to mess, that is, they grow, they swell
Speaker 1: when females are sexually active. That said smell typically trumps
Speaker 1: that as a cue. The females of most mammal species
Speaker 1: are out there clearly signaling when they're conceptive, when they're
Speaker 1: in the fertile phase. They're giving big, obvious cues and
Speaker 1: their scent or appearance. The natural question then becomes can
Speaker 1: human dudes tell when lady humans are fertile? There are
Speaker 1: these sort of coquil called a stinky T shirt studies
Speaker 1: where women have worn T shirts for a couple of
Speaker 1: nights and they're either conceptive or not conceptive, And men
Speaker 1: on average do prefer the scent of conceptive females, but
Speaker 1: they're not that good. They're telling you mean or they're
Speaker 1: getting a very close up with you know, they're smelling
Speaker 1: a T shirt that's been worn for a couple of days.
Speaker 1: So in normal just interaction now, they're not very good.
Speaker 1: Even women can't sense exactly when we're conceptive, though some
Speaker 1: women can feel the moment of ovulation. The biological details
Speaker 1: of our menstral cycles are hidden even from us. That's
Speaker 1: why women trying to get pregnant make color code their
Speaker 1: calendars or download apps like Fertility friend. The typical term
Speaker 1: that's used with regard to humans as that we have
Speaker 1: so called concealed ovulation. So there's not really any real
Speaker 1: cues of when women are ovulating, which is weird when
Speaker 1: you think about it. We're ignorant to one of the
Speaker 1: most basic bodily functions. There might be some very little cues,
Speaker 1: but for the most part, where a black box. This
Speaker 1: concealed ovulation might help explain why humans are game to
Speaker 1: have sex at any time in a woman's cycle. What
Speaker 1: you have is what has been termed extended sexuality. Sounds funky,
Speaker 1: but it's the extension part is really just referring to
Speaker 1: the fact that it's extended beyond that conceptive period, so
Speaker 1: there's non conceptive sex. There are some mammals who have
Speaker 1: extended sexuality, and in fact most primates actually have some
Speaker 1: period of extended sexuality. Interestingly, but as opposed to humans,
Speaker 1: usually in primates it's a few days. Possibly to the
Speaker 1: best of our knowledge. Are we the most extended extended sexuality?
Speaker 1: You can't get anymore. There might be a species or
Speaker 1: two that ties us, but we are as extended as
Speaker 1: you can get. So you really are having sex all
Speaker 1: the time. Maybe not relative to your friends or your
Speaker 1: ex guy, and is maddeningly likable new girlfriend. But compared
Speaker 1: to wild mammals who have never heard of Netflix and
Speaker 1: might not get to chill, you are Humans have a
Speaker 1: lot more sex during phases of the cycle where pregnancy
Speaker 1: isn't a possibility. It's worth noting that most mammals have
Speaker 1: different reproductive cycles than we do. Most don't get periods,
Speaker 1: and sometimes ovulation is even induced by the mail, so
Speaker 1: the systems are different. But still we're the ones doing
Speaker 1: it all over the calendar. We're the ones with concealed
Speaker 1: ovulation and extended sexuality. But of course none of that
Speaker 1: goes through your mind as making eyes at a special someone.
Speaker 1: Evolution doesn't have to shape your thoughts to shape your behavior.
Speaker 1: Most of us are driven to have sex just because
Speaker 1: it feels good. And with that, let's welcome Dr David
Speaker 1: Puts to stage from the Department of Anthropology at Penn State.
Speaker 1: Both David and his wife are sex researchers. In fact,
Speaker 1: we've published on orgasm together. So funny enough, I met
Speaker 1: her at a sex conference and she had just presented
Speaker 1: a paper on the genetics of the female orgasm. So
Speaker 1: after her talk we started talking about the topic and
Speaker 1: the science and YadA YadA, we have three kids. One
Speaker 1: of David's specialties is the female orgasm, which actually poses
Speaker 1: something of a mystery for academics. Nobody really knows what
Speaker 1: women's orgasm is for, and there's a lot of debate
Speaker 1: about whether it's for anything at all, whether it might
Speaker 1: just be a nonfunctional byproduct, and one suggestion is that
Speaker 1: it's a by aroductive orgasm in men, and that really
Speaker 1: in men, that's where the adaptation lies. Um, I think,
Speaker 1: just for a second, because I think too listeners who
Speaker 1: who aren't looking at this through an evolutionary lens, the
Speaker 1: idea that like, we don't know what a female orgasm
Speaker 1: is for, I think a lot of hands in the air, like, yeah,
Speaker 1: so you have to ask what it's for. Then you're
Speaker 1: not doing it right. Have you ever seen a female orgasm?
Speaker 1: When scientists say they don't know what it's for, they
Speaker 1: mean they're not sure how it might help us to
Speaker 1: survive and pass on our genes. Like, how could orgasms
Speaker 1: increase a person's likelihood of having kids and grandkids? Well,
Speaker 1: the dude's orgasm helps deliver sperm to where it has
Speaker 1: to go, so okay, we can see how that helps
Speaker 1: in procreation. Some scientists think female orgasms don't have any
Speaker 1: similar purpose. They just developed as a happy accident. The
Speaker 1: common analogy that's used as male nipples that you can
Speaker 1: have an adaptation in one sex, So you've got a
Speaker 1: functional trait in one sex that just some vestiges of
Speaker 1: it occur in the other sex. I think some dudes
Speaker 1: might be thinking, no, dude, my nipples are awesome, Like, yeah,
Speaker 1: they are not functionless brov. So yeah, they hold up
Speaker 1: my nipple ring. Yeah. So by function and evolutionary biologist
Speaker 1: means that there was some way in which it contributed
Speaker 1: to reproductive success ancestral e. Either by increasing survival or
Speaker 1: by increasing you know, mating success or you know survival
Speaker 1: of offspring or something like that. You could use your
Speaker 1: nipples for whatever you want, um, but that doesn't mean
Speaker 1: that they evolved for that purpose. But there's another camp
Speaker 1: that think female orgasms do serve a purpose of their own.
Speaker 1: Ladies and gentlemen, I present to you the up suck theory.
Speaker 1: The idea here is that the contractions of the female
Speaker 1: orgasm actually draw semen into the female reproductive tract, where
Speaker 1: it has a better chance of for realizing an egg.
Speaker 1: To test this idea, researchers of dosed women with oxytocin,
Speaker 1: a hormone that triggers the muscle contractions during orgasm two
Speaker 1: different labs found that women who went into the lab
Speaker 1: those that were treated with oxytocin that that caused the
Speaker 1: transport of a fluid the same viscosity of seemen up
Speaker 1: into the overducts, and the closer the women were to ovulation,
Speaker 1: the more of that transport was just into the oviduct
Speaker 1: where the egg was coming down. So is there essentially
Speaker 1: an argument to be made that if a woman orgasms
Speaker 1: with a partner, she's more likely to be impregnated by
Speaker 1: him then when she has sex where she does not organs. Yes, yes,
Speaker 1: but we don't really know that it's clearly not necessary, right,
Speaker 1: I mean, plenty of women have kids that have never
Speaker 1: had an orgasm. The up stuck theory is still hotly debated.
Speaker 1: Other experiments have yielded results that don't support the idea.
Speaker 1: And so far no one's run a big study to
Speaker 1: find out if women's orgasms during actual sex are more
Speaker 1: likely to lead to a pregnancy in the real world.
Speaker 1: But up suck isn't the only possible purpose for the
Speaker 1: female orgasm. The intense feeling of pleasure, the idea that
Speaker 1: that has no function at all. It's hard to swallow because, uh, jeez,
Speaker 1: I shouldn't say, come David, better angels, let's keep it classy.
Speaker 1: It's hard. It's hard to believe because you would think
Speaker 1: that that kind of intense feeling would have some effect
Speaker 1: on behavior. Right. It seems likely, and there's some evidence
Speaker 1: that this is the case, that if women have more
Speaker 1: orgasms with a partner, then they feel more emotionally close,
Speaker 1: and that that would then tend to sort of strengthen
Speaker 1: a long term pair bond. So the contractions of a
Speaker 1: female orgasm might improve the likelihood of fertilization. Or maybe
Speaker 1: the pleasure is the purpose and that it strengthens the
Speaker 1: emotional bonds between sexual partners. They're different hypotheses, but they're
Speaker 1: not mutually exclusive. Steve Gang said, the dude who told
Speaker 1: us about mammal sex at the very start of this program.
Speaker 1: Says that our concealed ovulation may also encourage pair bonds
Speaker 1: between mates. And here's why. Mammal species males don't care
Speaker 1: for they're young at all, But humans take a lot
Speaker 1: of work to raise and concealed ovulation maybe a strategy
Speaker 1: to help get dad's involved. This takes a little bit
Speaker 1: of explaining, so bear with me. Picture a world where
Speaker 1: it's somehow very obvious when human women are in the
Speaker 1: fertile phase of their psycho they act a certain way,
Speaker 1: or they look a certain way, or they only whistle
Speaker 1: show tunes, whatever, all the guys would be interested in
Speaker 1: mating at this time. The proverbial milkshake bringing all the
Speaker 1: boys to the yard. But with an abundance of boys
Speaker 1: and only so much milkshake, not every dude would get
Speaker 1: the chance to copulate. Males are not of equal ability
Speaker 1: to be able to take advantage of that. There are
Speaker 1: some that are going to be more dominant and they
Speaker 1: can monopolize the fertile phase matings. M h. The alpha
Speaker 1: males could just chase the other suitors out of the yard.
Speaker 1: Most offspring are sired by just a few dominant males. Then,
Speaker 1: when the lady next door enters her fertile phase, the
Speaker 1: dominant males would head over to her yard, leaving the
Speaker 1: pregnant female to raise the young alone. But this situation
Speaker 1: doesn't serve the genetic interests of the female all that well.
Speaker 1: For her, it'd be better if both parents cared for
Speaker 1: the baby, improving the kid's chances of growing up and
Speaker 1: one day mating two. The problem with those dominant males
Speaker 1: is they're doing just fine. Caring for babies would take
Speaker 1: away from the dominant males mating time, which is their
Speaker 1: best bet for genetic success, and so to mate with
Speaker 1: males who would provide care for her young. Female bodies
Speaker 1: evolved to hide their fertile phases by concealing ovulation. Then
Speaker 1: the male, the dominant males can't just guard, so that's
Speaker 1: an argument for the evolution of concealed opulation that arose
Speaker 1: early antien Needy late nineteen seventies. The alpha males can't
Speaker 1: fend off other suitors from all the females all the time,
Speaker 1: so other males get the chance to mate, and these
Speaker 1: non dominant males, they're not the high octane studs who
Speaker 1: can fight off rivals and mate with all the females.
Speaker 1: They're best chance at getting their genes out there is
Speaker 1: to lock it down, to form pair bonds and invest
Speaker 1: in the kids to give them a better shot at
Speaker 1: growing up and continuing the line. The top theory I
Speaker 1: think is that extended sexuality is about biparental care. It
Speaker 1: co evolved with biparental care and humans, and that extended
Speaker 1: sexuality is partly about strengthening that pair bond, ensuring investment
Speaker 1: from a primary partner. In conversations like these, it can
Speaker 1: be tempting to try to retrofit the whole world with
Speaker 1: an evolutionary explanation. But not every feature of our body
Speaker 1: or our behavior is perfectly adapted to our environments. Evolution
Speaker 1: works on transmutations, and we're just the best models that
Speaker 1: have emerged so far. And also, responsible scientists need more
Speaker 1: evidence than yeah, that it totally makes sense. What do
Speaker 1: we know for sure about extended sexuality in humans? If anything? Well,
Speaker 1: being a scientist, very very cautious about what we say
Speaker 1: that we know for sure because it's tough to prove stuff,
Speaker 1: And that, my friends, is the full and complete story
Speaker 1: of human sexuality. We ovulate in secret, we get it
Speaker 1: on all the time, and female orgasms are Hello, mysterious. Okay,
Speaker 1: let's bring up the house lights drive to say if
Speaker 1: everybody to be bartenders and good night. Nope, wrong, stop.
Speaker 1: Obviously we cannot end the show that way. We can't
Speaker 1: talk about all this sex we're having only in terms
Speaker 1: of genetics and reproduction and up sick. Our horizontal lives
Speaker 1: are shaped by culture, too, so let's pan out for
Speaker 1: some much needed context. So far, we've been using the
Speaker 1: terms male and female as absolute and discreet, which isn't
Speaker 1: how we consider them in the real and complicated world.
Speaker 1: We've also been pretty heteronormative. Let's bring in sex historian
Speaker 1: Kate Lister for a quick vocab check on that last term.
Speaker 1: Can you tell me what the term heteronormative means. It's
Speaker 1: when all of our assumptions and our biases are coming
Speaker 1: from a place where we are making pains and vagina
Speaker 1: sexual sex the default, and everything else around that is
Speaker 1: not the default. Homosexual behavior has been abundantly documented all
Speaker 1: over the animal kingdom, from swans to lions to lizards,
Speaker 1: and sex isn't only procreative either if it's about making babies,
Speaker 1: And how do we account for masturbation and oral sex
Speaker 1: anal sex same sex sex. Keith is a researcher. It
Speaker 1: leads Trinity University in England. In her book A Curious
Speaker 1: History of Sex, she documents all sorts of sexual fantasies
Speaker 1: and fears and prohibitions throughout the ages. The actual act
Speaker 1: of sex itself is pretty standard, but what changes and
Speaker 1: what's different is people's attitudes to it, the rituals that
Speaker 1: go around it, the things that are shamed, things are acceptable,
Speaker 1: things that are condemned. The Puritans who left our jolly
Speaker 1: shows and turned up on yours, bringing with them sexual
Speaker 1: repression and shame and mad hats with buckles on. That
Speaker 1: was they were really caught up about sexuality. And the Puritans,
Speaker 1: they were a movement that started largely out of this
Speaker 1: denying pleasure, but a very excessive and strict version of
Speaker 1: Puritanism that rejected where they thought of as Catholic decadence,
Speaker 1: and sex was something very much that they wanted to repress.
Speaker 1: But a whole society can't just go called turkey. You
Speaker 1: have to have some sex otherwise we're all just going
Speaker 1: to die out. So then it becomes about controlling the
Speaker 1: act very very carefully, and the Puritans are sort of
Speaker 1: very much in that vein. You could have sex, but
Speaker 1: you couldn't enjoy it. It was for making babies only.
Speaker 1: Victorian England has become sort of like the poster child
Speaker 1: for sexual hang ups. There is a real emphasis on
Speaker 1: trying to stop people, women and men, but particularly men
Speaker 1: from masturbating. And what you've got anti masturbation devices that
Speaker 1: came around in sort of the mid nineteenth century, and
Speaker 1: the idea was to stop quote unquote nocturnal emissions. So
Speaker 1: that's a wet dream. So what you get is these rings,
Speaker 1: sper matter zoa rings, which are basically were tied on
Speaker 1: the penis but had really sharp, jagged teeth on the inside,
Speaker 1: so you'd put the penis into it, and then the
Speaker 1: idea would be that if he got an erection the
Speaker 1: middle of the night, the teeth would bite out and
Speaker 1: wake him up before he could lose his special seed. Okay,
Speaker 1: So so I am currently looking at your hardcover book
Speaker 1: and there is like a pen and ink drawing that's
Speaker 1: labeled the four pointed urethril ring. Yep, yep. And it's
Speaker 1: quite horrendous thing, isn't it. Yeah, it's one of those things.
Speaker 1: It's like even as even as a lady. The legs
Speaker 1: cross a little bit, isn't it's it's that awful. But yeah,
Speaker 1: it looks like a napkin ring yep, that has spikes
Speaker 1: on the inside of the circumference. Yeah, that's pretty much it. Yeah,
Speaker 1: it's a bummer kate, it's a realm. But Victorians also
Speaker 1: produced a bunch of kinky porn, like they're really into
Speaker 1: stuff like whips and lashes. So there's this sort of
Speaker 1: choreograph hypocrisy about what's publicly forbidden but still happens in private.
Speaker 1: Look at our own society, you know, Paul, you know
Speaker 1: I don't watch Part up Master Bag. Of course you do.
Speaker 1: We just don't talk about it, impolite society. With the
Speaker 1: passage of time and a better understanding of our own bodies,
Speaker 1: our attitudes about sex and sexuality have changed in big,
Speaker 1: like head spinning ways. The pill sparked a revolution. It
Speaker 1: just radicalized everything because suddenly you could control your own
Speaker 1: reproduction and it placed in the hands of women as well.
Speaker 1: That's amazing. I do get asked a lot. Was there
Speaker 1: ever a period in history when we had it all
Speaker 1: figured out, when when everyone was just coverting in a
Speaker 1: shame free sexual paradise. And the answer to the question
Speaker 1: is is the closest we've ever come is probably now,
Speaker 1: and which feels really uncomfortable because like we look around
Speaker 1: and to go, you're freaking kidding me, Like there's still
Speaker 1: places around the world where people will be killed for
Speaker 1: their sexuality, but the fact that there is a movement
Speaker 1: to not shame people, to not execute people because of
Speaker 1: their sexuality or chemically castrate them or do so, we
Speaker 1: are the closest now that we've been to getting it
Speaker 1: all figured out. And that's quite scary. Humans have culture
Speaker 1: and birth control, religious mandates and weaponized napkin rings. So
Speaker 1: does that put us above the freight of evolutionary forces?
Speaker 1: I'm betting that when researchers Steve goes to a restaurant
Speaker 1: with friends, everybody at the table is fascinated by his work,
Speaker 1: but few are really convinced it applies to their own lives.
Speaker 1: Did you ever talked to people who kind of dismiss
Speaker 1: your work as reductive, like, Oh, that's the way it
Speaker 1: works in animals, but that's not the way it works
Speaker 1: for us. Well, certainly some people what they say is, oh,
Speaker 1: the magic is gone, but I don't see it that way.
Speaker 1: The thing is the magic is what you feel. But
Speaker 1: what's under the magic, what's giving rise to all this?
Speaker 1: The loves there? The question is why is the love there?
Speaker 1: It's at a different level of analysis. The way that
Speaker 1: we experience lust and love of and jealousy and intimacy.
Speaker 1: They feel so real, so fundamental to our humanity, that
Speaker 1: I don't think we want them undermined by chemical accounts.
Speaker 1: We don't want to hear our most poignant experiences boiled
Speaker 1: down to only genes and reproduction. But I agree with Steve,
Speaker 1: there are motors to the magic, and learning how the
Speaker 1: gears fit doesn't have to break the spell. If concealed
Speaker 1: ovulation encourages pair bonds, Hey lucky us, a proclivity to
Speaker 1: love one another is written in the code of our design.
Speaker 1: If our species has evolved to have sex all around
Speaker 1: the cycle, Hey lucky, Yes, put a date night on
Speaker 1: the calendar. Any day will do. And that concludes our show.
Speaker 1: Be safe, be kind to one another, maybe make a milkshake,
Speaker 1: see who comes around, and for the final bows. Be
Speaker 1: Human is a BBC World Service, an American public media
Speaker 1: co production with I Heart Media and hosted by MESA.
Speaker 1: Next Time a deeply human Our topic is standing in
Speaker 1: line and why it turns us into low rage monsters.
Speaker 1: There is a meme that's been going around. It has
Speaker 1: a picture of Beyonce and it says, why aren't you Beyonce?
Speaker 1: She has the same twenty four hours you do, um,
Speaker 1: and I don't think that's accurate at all. We all
Speaker 1: do have objectively twenty four hours, but we are often
Speaker 1: forced to use those hours in very distinct ways. I
Speaker 1: think about people who have very long commutes to their
Speaker 1: second job, and time is very different for them. The
Speaker 1: people in a grocery store line who have to, you know,
Speaker 1: use food stamps or cash and count coupons. They're using
Speaker 1: their time at that check out stand very differently than
Speaker 1: I have to. Oh,