Podcast Transcription

Steve Mirsky:       This Scientific American podcast is brought to you by Audible.com, your source for audiobooks and more.  Audible.com features more than 100,000 titles, including science books like Mary Roach’s new book, Gulp: Adventures on the Alimentary Canal, and Thinking Fast and Slow by Nobel laureate Daniel Kahneman.  Right now Audible.com is offering a free audiobook and a one-month trial membership to the Scientific American audience.  For details go to Audible.com/SciAm.

Welcome to the Scientific American podcast, Science Talk, hosted on June 27, 2013.  I am Steve Mirsky.  On this episode-

Jesse Bering:       I mean typically when we have brain damage we have this effect where it essentially sort of waters down our sex drive, but there are certain neurological disorders that have the opposite effects; it makes us very randy, it makes us hypersexual.

Steve Mirsky:       And that is scientist and author, Jesse Bering.  He’s a psychologist and the former director of the Institute of Cognition and Culture at Queens University, Belfast.  He now lives and writes in Ithaca in Upstate New York, but swung through New York City last summer on a tour for his then-new book, Why is the Penis Shaped Like That?: And Other Reflections on Being Human.

The discussion that follows is at times frank and let’s call it earthy, so if you have sensitive sensibilities turn back now.  Jesse and I spoke at Scientific American.

Jesse, I’m holding the book here, and as you can see, I have a piece of paper covering the cover-

Jesse Bering:       I see that.

Steve Mirsky:       -because I was reading it on the subway.  And while-

Jesse Bering:       You’re ashamed of it?

Steve Mirsky:                I wasn’t ashamed.  I was just figuring why bother to get into it.

Jesse Bering:       You were cautious.

Steve Mirsky:       I was cautious.

Jesse Bering:       Yes.

Steve Mirsky:       Why is the Penis Shaped Like That?: And Other Reflections on Being Human, with two - now these would appear to the lay observer to be walnuts, but we both know that they represent the prostate.

Jesse Bering:       Yes, I think that was the intention, it’s sort of double entendre.

Steve Mirsky:       Because you cannot see an article about the prostate without it being referred to as the walnut-sized organ or the walnut-sized gland.  Right.

Jesse Bering:       Yes.  Yes.  Yes.  But it’s innocuous enough, I think.

Steve Mirsky:       Exactly.  And there are two of them.

Jesse Bering:       Although it is a little uncomfortable actually when you put it in that context and you see the close-up images of a walnut, sort of the outer shell.  It looks quite scrotal.

Steve Mirsky:       It definitely does.  It definitely does.  Although this would be much more likely to survive some of the impacts that you discuss-

Jesse Bering:       Just a bit, yeah.  Just a bit.

Steve Mirsky:       -in the book.  The book is wide-ranging, it’s very entertaining.  You know, you have a really engaging style, and the information in it seems to be very well-cited scientifically.  So you’re not just, you know-

Jesse Bering:       It’s not me pontificating.  I mean this is actual science that I’m referring to, yes.

Steve Mirsky:       So, you know, why don’t we - we’ll talk about a few of the specifics in the book.

Jesse Bering:       Sure.

Steve Mirsky:       But since the title is Why is the Penis Shaped Like That? why don’t you give us the nickel tour of the penis and why it is shaped like that?

Jesse Bering:       So it’s a, you know, that’s the titular essay in the collection, and-

Steve Mirsky:       Let’s stick to the penis.

Jesse Bering:       Yeah, we’ll stick to the penis for a while.  So it is a curious appendage.  I mean if you think about it, it’s not intuitively shaped.  There’s no obvious reason, in the absence of some sort of evolutionary theory, that it should look the way that it actually does, and it does look very different from the penes - that’s the plural of penises, I’ve learned - of other primate species, other closely-related primate species, including chimpanzees.  And unfortunately I saw too many chimpanzee penises as a graduate student when I was doing work with them.  Didn’t really want to see them, but I couldn’t help but notice them.

But the human penis is distinct in a number of ways.  I mean first of all, it’s very big.  It’s large from sort of an animal kingdom sort of broader perspective.  So that’s one telling sign that’s quite revealing.  It also has that very distinctive glans head with a fairly, you know, noticeable coronal ridge it’s called, which is sort of the umbrella lip underneath the glans.  And this is an erect penis we’re talking about, when we’re actually tumescent.  And the - you know, what was really interesting to me was that nobody had ever, you know, bothered, until very recently, to stop and consider why it looks the way that it actually does.  It took an evolutionary psychologist named Gordon Gallup, who I’m very fond of and I think he’s a very innovative theorist, has a number of arguments that I find incredibly persuasive, if speculative,-

Steve Mirsky:       So we’re talking about the Gallup poll, literally?

Jesse Bering:       Yes, literally.  And the argument in a nutshell - it’s kind of hard to avoid these puns with this type of conversation - is that the penis evolved this particular morphology to retract the semen of - and the sperm cells, obviously in particular, of males that had copulated with a particular female within a certain window of time before you’re having sex with her.

Steve Mirsky:       And this is not uncommon.  I mean many animals and insects have equipment that sweeps out-

Jesse Bering:       Specialized to - yes.  Yes.

Steve Mirsky:       Right.

Jesse Bering:       So I talk in the book about other, you know, there are some other species that have similarly-shaped male genitalia to basically, to sweep out or to retract the sperm cells of other males.  It’s all sperm competition; I mean that’s the heart of the argument.  But he’s got so many - I mean Gordon’s got so many sort of interesting little caveats that are part of the argument.  So, you know, one counterpoint perhaps would be, well, you know, if that were true why would we - you know, it’s kind of self-defeating, we’re pulling out our own semen too.  But anybody with a penis knows, that has actually ejaculated, knows that you actually get quite flaccid very quickly after you achieve an orgasm and, you know, further stimulation is quite - it’s not painful, but it’s not necessarily pleasant; it’s almost uncomfortable.  And there’s a period of impotence for, you know, about at least an hour or so, but up to 24 hours after ejaculation.  So there seem to be these built-in mechanisms that facilitate you ejaculating your sperm cells as deep into the vaginal canal as possible and then stopping. 

So I mean that’s the gist of his hypothesis.  And of course he’s got all these really great experiments where he looks at - he’s used different-shaped phalluses, dildos basically, that have more or less-prominent coronal ridges.  And, you know, there’s this - he actually has a set of ingredients for producing artificial semen so he can literally sort of detect the amount of semen that would be retracted by differently-shaped coronal ridges.  And as you can imagine, a dildo or a phallus that has no glans head, that’s simply straight, is not very effective at pulling out semen. 

Steve Mirsky:       That must have been a fascinating grant proposal to write.

Jesse Bering:       Yeah.  You know, evolutionary psychologists are - they do some really interesting work.  And I know, you know, just speaking to my colleagues, and some studies that I’ve done myself actually, it does take some argumentation to persuade an ethics review board that this is important work, theoretically meaningful work, even though it has this sort of intrinsic giggle factor associated with it.

Steve Mirsky:       You have, the book, as I say, is far-ranging, but just let’s just sort of pick a few sections to talk about there.

Jesse Bering:       Sure.

Steve Mirsky:       One of the things I found really fascinating was the chapter on brain damage and how that can have a profound effect on peoples’ sexuality.

Jesse Bering:       Right.  Right.  So I mean typically when we have brain damage we have this effect where it essentially sort of waters down our sex drive, it decreases our libido.  But there are certain neurological disorders and insults to the brain that are localized in particular regions that have the opposite effects; it makes us very randy, it makes us hypersexual.

Steve Mirsky:       Mm-hmm.  There’s an episode of House actually, where-

Jesse Bering:       Yeah.  Somebody was telling me about that.  I didn’t see the episode, but somebody has mentioned that to me.

Steve Mirsky:       Yeah.  A woman is just completely - an elderly woman is completely sexualized and she’s just after everybody, and he finds that she has suffered some brain damage.

Jesse Bering:       Right.

Steve Mirsky:       But she’s enjoying herself, so they’re not going to fix it.

Jesse Bering:       Right.  Okay.  Well it depends on what she’s doing, I suppose, with her hypersexuality.

Steve Mirsky:       Right.  She’s not - right.  Exactly.  She’s not actually-

Jesse Bering:       Breaking the law or something like that.

Steve Mirsky:       Right.

Jesse Bering:       So but those are the cases where I mean you actually have some type of social transgression, where somebody with some pronounced hypersexuality that results from brain damage commits a crime, a sexual crime, and it’s very difficult, I think, for people to not attribute responsibility to them as making a decision to do that.  So sexuality in the moral domain I think is very interesting, because we don’t - it’s sort of the one domain where people like to think we’re in control over our decision-making. 

But, you know, I talk about in this chapter that you’re referring to a woman that was diagnosed with Kluver-Bucy syndrome, which is a notorious brain disorder where hypersexuality results.  And this woman was actually quite prudish, you know, in her - you know, prior to actually being afflicted with this disorder.  A very reserved and quiet middle-aged woman, but all of a sudden now that she has this she’s, you know, she’s soliciting her family members, she’s - they brought her to the emergency room, she’s performing fellatio on an elderly man in the waiting room.  And it’s strange, I think, for us to, you know, get our heads around that, that she can’t help what she’s doing.

I mean, and it really does sort of solidify to me the physicality of our decision-making and our free will is, you know, in my opinion at least, free will is largely an illusion.  Everything, if you look deeply enough, has some sort of physical causal mechanism.  But like I said, there’s this sort of tension when we’re thinking about truly disturbing sort of sexual crimes and those types of things.

Steve Mirsky:       Mm-hmm.  And you talk in that chapter about a guy who has a brain tumor and he’s behaving really inappropriately sexually, and they deal with the tumor and by all accounts he returns to normal.

Jesse Bering:       Right.

Steve Mirsky:       And the tumor comes back, his behavior gets bad again-

Jesse Bering:       Right.

Steve Mirsky:       -and then again, by all accounts, when they deal with it again he returns to normal.

Jesse Bering:       Right.  So there are a couple of cases where there’s a brain lesion and there’s what’s known as new-onset pedophilia, for example.  I think that’s the case that you’re talking about-

Steve Mirsky:       Mm-hmm.

Jesse Bering:       -where he’s, you know, he’s probably - I think he was coming on to his 12-year-old stepdaughter or-

Steve Mirsky:       Right.

Jesse Bering:       -sort of doing very inappropriate things.  He had the brain tumor removed and everything was back to normal.  You know, he was back with his wife, the daughter was living there.  Then the brain tumor came back and again he was doing inappropriate things.

So the - I guess one of the mysteries is whether or not - for example, in that case he really did have some implicit - some latent pedophilic tendencies, and the brain lesion somehow affected his inhibition.  It’s not qualitatively a new, sort of new-onset pedophilia out of nowhere; it’s that the brain lesion somehow disrupted his ability to control himself normally.

And those are the types of issues that I think researchers are still grappling with in terms of whether, you know - and that’s one case.  There are several of these new-onset pedophilia cases, but there are also cases where somebody all of a sudden just becomes a transsexual or transvestite or, you know, they become bisexual or homosexual and, you know, normally they’re heterosexual.  So then the big question again is, you know, were they always homosexual at some level, or were they always bisexual and somehow the brain tumor or lesion somehow just flushed it out or made it more explicit, rather than changed it qualitatively?

Steve Mirsky:       And you do see other behavioral, massive behavioral changes; people might get more irritable.  You also see people whose political affiliations completely reverse after a brain lesion.

Jesse Bering:       Right.

Steve Mirsky:       So a lot of very interesting and unusual things can happen.

Jesse Bering:       Right.  Right.

Steve Mirsky:       You talk - let’s get back to the scrotum for a second.

Jesse Bering:       Sure.  I’d love to.

[Laughter]

Steve Mirsky:       Because you talk in the book about the amazing pain-

Jesse Bering:       Yes, excruciating.

Steve Mirsky:       -that’s available for men.  Everybody has been, you know, kicked in the groin or-

Jesse Bering:       Unfortunately, yeah.

Steve Mirsky:       -you know, I’ll tell you, when I was a paperboy, many years ago, I used to hop the fences between the houses if they had adjoining front porches.  So it would save me a trip down and up the-

Jesse Bering:       I hear a painful story coming up.

Steve Mirsky:       Well, you know, I slipped once and came down right on the rail from, you know, just from a couple of inches.

Jesse Bering:       Right.  Right.

Steve Mirsky:       And every - I mean I have not given up rail-hopping in my dotage here, but I do it exceptionally carefully whenever I do it now.

Jesse Bering:       Right.  Yes.

Steve Mirsky:       Because that pain was just, you know, mind-boggling.

Jesse Bering:       Right.  Right.

Steve Mirsky:       So why - what - why would evolution have constructed - clearly it didn’t have the pain in mind - what’s going on there?

Jesse Bering:       Well, it wasn’t anticipatory.  I mean-

Steve Mirsky:       Right.  Right.

Jesse Bering:       -the sense in that _____ ______.  But it worked.  And this is, again, another - this is another extension of Gordon Gallup’s model of male genitalia, that the degree of pain that we experience with any given organ in our bodies or appendage or any part of your body that’s protruding is directly related to its reproductive significance, its importance from a genetic fitness perspective.  So, you know, the testicles, it’s slightly counterintuitive that they would be, you know, basically out of our body in a very thin sort of satchel that are so imminently vulnerable to assault or damage.  And the hypothesis is that as a consequence of them, and, you know, natural selection sort of, as you know, works with what it has.  And because we produce sperm cells more prodigiously when the ambient body temperature is a certain way outside of the body and slightly cool, there was a selective pressure forced for that, for the testicles to be outside of the body.  But as a consequence of that, they’re in danger.

So by having these very painful encounters developmentally to our scrotums or testicles, and learning very quickly from them and how to handle them essentially when we’re interacting in the environment, we are much more likely to protect them, and therefore keep them healthy and live long enough at least to actually use them effectively and reproduce ourselves.

Steve Mirsky:       You know, you could’ve almost used as a cover illustration soccer players awaiting the-

Jesse Bering:       Right, covering their groins.

Steve Mirsky:       Right.  Exactly.  All lined up with their hands over their groins.

Jesse Bering:       Yes.

Steve Mirsky:       You talk in the book also about cannibalism and how it would appear to be an evolutionary strategy, which has always struck me as just being almost expected, because organisms don’t like to let protein go to waste because of some kind of cultural imperative.

Jesse Bering:       Right.  So again, so there’s this evolutionary hypothesis that cannibalism is not so exotic or foreign to our species, that in fact ancestrally there would’ve been numerous occasions where it would have been biologically adaptive to eat the meat of other human beings.  And there’s - like you said, there’s quite a bit of protein in the human body.  I think somebody at some point, some anthropologist had crunched the numbers and there was, you know, 44 pounds of-

Steve Mirsky:       I think it was a lot more than that, actually.

Jesse Bering:       I can’t - it’s some - it’s quite a bit of meat.

Steve Mirsky:       It was closer to 70, if I remember.

Jesse Bering:       Sixty-six pounds?  I don’t know, something _______ or ____.

Steve Mirsky:       I think it was 66, yeah.

Jesse Bering:       Okay.  So it was quite a lot of meat that would otherwise simply go to waste.  So, you know, starvation conditions would have been very prevalent historically, both after we became, you know, both before we were sedentary and afterward, with famines and droughts and all sorts of dietary problems that we would have historically run into quite frequently.  And there are certain physiological cues or evidence left in the human body that suggests that we might, in fact, have specific adaptations to prevent parasitical or microbiological - micro-organisms from somehow making us sick by eating other human beings’ flesh.

And, you know, we were just one of, you know, millions of species that have, you know, walked and flown and swam in the Earth, and many of them do engage in cannibalism from time to time.

Steve Mirsky:       And even their own offspring.

Jesse Bering:       Even their own offspring.  You know, especially if it’s sickly offspring, and, you know, they need some source of protein or something like that.  And, you know, you find it in primate species that are trying to make more room for more, you know, that eat their sickly infants that aren’t likely to survive anyway.  It’s disturbing, it’s gross, but, you know, it is what it is; it’s nature.

Steve Mirsky:       We’re not advocating it, by the way.

Jesse Bering:       No, I wouldn’t recommend it.

Steve Mirsky:       We’re just pointing out that it’s probably-

Jesse Bering:       Although apparently it does taste quite good, I mean certain parts of the body.

Steve Mirsky:       That’s what they say. 

Jesse Bering:       That’s what they say, the epicures say that.

Steve Mirsky:       Yeah, 66 pounds of edible food-

Jesse Bering:       Sixty-six pounds, okay.

Steve Mirsky:       -including fat, connective tissue, muscle, organs, blood, and skin.  Protein-rich blood clots and marrow are said by the rare connoisseur to be special treats.

Jesse Bering:       Yes.  Yes.

Steve Mirsky:       Let’s talk about this gorilla that you tickled his toe.

Jesse Bering:       King, yes.

Steve Mirsky:       Now how do you wind up in-

Jesse Bering:       Tickling a gorilla’s _____?

Steve Mirsky:       -in physical contact with a gorilla?  Yeah.

Jesse Bering:       Oh, okay.  Well, this was - when I was an undergraduate student in Florida I - when I was in high school I had absolutely no idea what I wanted to do.  Completely clueless, wasn’t particularly scientifically-oriented.  I - you know, I wasn’t a very good student, I had very little interest in school; nothing really appealed to me.  But when I moved to Florida when I was 18 years old there was an article in the Miami Herald about a woman that ran a sanctuary in Parrot Jungle, which is a sort of theme park in Parrot Jungle.  And she was raising infant orangutans and chimpanzees at that point.  And then they were - she was selling paintings that they would paint; she was trying to make - collect money to create a proper sanctuary for them, where they wouldn’t actually be exposed to the public and it wasn’t - and they could sort of lead natural lives among others of their kind.

And I got sucked into the sort of great ape sanctuary world.  And I-

Steve Mirsky:                You are a great ape yourself.

Jesse Bering:       I am - yeah, technically we are, you know, Jared Diamond would say we’re the third chimpanzee.

Steve Mirsky:       Right.

Jesse Bering:       And I think that’s what really appealed to me; I finally found, you know, evolutionary theory to me was - you know, it was Biblical in the sense of really sort of hitting me and being so meaningful and transforming all the sort of doubts I had in my mind about religion.  And everything made sense when I first encountered, you know, an organized, systematic, theoretical model of both human morphology and human behavior.  So chimpanzees really appealed to me because they were so like us physically, behaved a lot like us as well, but of course, you know, there are several million years that separate us from the common ancestor.

Anyway, to get back to your question about the gorilla, I, you know, just from that world I met a woman that ran a sanctuary in very south in Miami; Hialeah, I believe, at Monkey Jungle.  And they had one gorilla there that had been there for, you know, 25 years.  I think he was 29 years old when I first started working with him.  And I was, at the time, you know, finishing school, and I needed a thesis - I was writing a thesis project for my, you know, honors thesis.  And I thought it would be a good idea, because he was all alone - he was one of the very few singly-housed gorillas in the U.S. at the time.  And he had a lot of sort of abnormal behavioral traits because of that; he was isolated from other gorillas, when he was little he was raised in a circus and they pulled his teeth out.  You know, quite a difficult, cruel existence that he’d had.

Then I thought that, you know, it would be interesting to interact with him, try to enrich his life somehow.  And I had this strange idea of giving him music therapy to encourage him to be more active in his concrete and steel sort of cage.  And I don’t think that was very successful as a project, though he did seem to like the Three Tenors.  It probably irritated him more than anything else.  But I had women at the - they worked at a nursing home and they were music therapists by training, and they would actually sort of sit in front of his cage and sing to him.  So he had a lot of interesting stimulation.

Steve Mirsky:       Right.  So in the book you said you played the Three Tenors and Sinatra.

Jesse Bering:       Sinatra, yeah.

Steve Mirsky:       He didn’t care for Sinatra that much?

Jesse Bering:       I don’t think it was - I don’t think he was into Sinatra, no.

Steve Mirsky:       Okay.  Must’ve been the arrangements.

Jesse Bering:       Yes, it could’ve been something like that.  And then - and he, you know, I just kind of struck up a friendship with him really.  I mean I had such close contact with him and he - you know, I would play chase with him and tickle his toes and-

Steve Mirsky:       You were not in the ______ enclosure.

Jesse Bering:       I was not - I certainly didn’t go in the enclosure, no.

Steve Mirsky:       Right.  ‘Cause that could be dangerous.

Jesse Bering:       But he would put his, you know, put his big feet out, his toes through the bars and, you know, I would tickle and he would laugh, and it was a very, you know-

Steve Mirsky:       But are you sure he was actually laughing?

Jesse Bering:       Well, gorillas have - they have a laughter expression.  It doesn’t sound much like ours; sort of very guttural heaving, you know, their shoulders go up and down.  But that’s the only - the only time they do it is when you either tickle them or you’re chasing with them and they’re really excited.

Steve Mirsky:       What if you slip on a banana peel and they see?

Jesse Bering:       I don’t think they have that type of humor actually, no.

Steve Mirsky:       Okay.  Okay.

Jesse Bering:       But he certainly is - he was ticklish.  But, so that’s how I ended up working with King.  And he’s since then - the good news is that he’s actually - they’ve created a large sort of island environment for him.  So although he’s still alone, and he’s close to 40 years old now, he has, you know, a very lush, more naturalistic type of surroundings hat he spends his days.

Steve Mirsky:       When was the last time you saw him?

Jesse Bering:       Not since then.

Steve Mirsky:       Okay.

Jesse Bering:       I mean I was probably 21.

Steve Mirsky:       I was just wondering if he might even recognize you. 

Jesse Bering:       I doubt it.  I don’t know.  Who knows?  It’s, you know, it’s very difficult to tap into things like autobiographical memory with non-verbal primates.

Steve Mirsky:       Right.  But you tickled him and you seemed to get an actual kind of laugh response.  And you spend the rest of that chapter talking about the researcher who is convinced that if you tickle rats they will laugh. 

Jesse Bering:       Right.  Right.  So Jaak Panksepp is the guy that’s done that work, and he has been building this case that not a sense of humor, but laughter has very deep phylogenetic origins.  And we find that even in rats, which are very distantly related to human beings, of course.  So he’s done controlled research where he looks at their sort of ultrasonic vocalizations when you interact with them physically, again, tickling them basically or playing with them, you know, sort of touching the back - the nape of their neck, you know, certain areas that they’re very sensitive, and when they’re wrestling with each other.  And only when there are these sort of very pleasurable sort of social interactions do they produce this sound. 

Whether it’s a direct analogy to human laughter is a little bit controversial, I think.  And he had a very difficult time making the argument, or people believing him, at least, that it’s the same thing as laughter, or that they’re really laughing.

Steve Mirsky:       But there is a specific response-

Jesse Bering:       A very specific _______.

Steve Mirsky:       -to that tickling of the sensitive area.

Jesse Bering:       Yes.  Yes, yes.  And, you know, some great - one of the things that he found is that if you tickle a rat that rat will pursue your hand over another person’s hand that hasn’t interacted with them positively like that.  And they also like to interact with other rats that they produce these sounds with - that they’ve produced these sounds with in the past.  So adult rats that they’ve wrestled with, for example, the juvenile rats will pursue further interactions with them over ones that they didn’t have that - they didn’t make that vocalization.

Steve Mirsky:       Mm-hmm.  What do you think it is about this subject matter - I mean a lot of the book is about human sexuality, but not all of it; some of it’s just about the quirks, the qualities that make us human, and that maybe are shared by other species that we’re not really appreciate of. 

Jesse Bering:       Right.

Steve Mirsky:       What do you think it was that really attracted you to this material that you wanted to spend so much time writing about it?

Jesse Bering:       Well, most of my professional academic research is in the area of social cognition.  And the big question from an evolutionary perspective is whether we are the only species that can think about others’ thoughts and also can think about our own thoughts; it’s what’s called a theory of mind.  Do we theorize about the abstract sort of hypothetical mental states of both ourselves and of other people?  And so that to me is the common denominator sort of streaming throughout this book.  I think it had dramatic effects, the evolution of this theory of mind mechanism would have had dramatic effects, for example, with both the way that we interpret human sexuality and the way that we behave sexually. 

I mean if you think about the difference between copulation of other species and copulation in human beings, with other species it’s fast.  I mean it’s, you know, in a couple of seconds it’s over basically.  Human beings have, you know - they copulate, other species.  We copulate too, but it oftentimes turns into a lovemaking sort of session, where we’re really sort of taking the perspective of the person that we’re having sex with.  And that’s where all these, you know, really complicated sort of moral issues of consent and, you know, making people comfortable sexually when you’re having intercourse with them, all these things are evolutionary novel to our species, I believe. 

So I think that theory of mind is a big part of all these essays.  Maybe not every single one, but most of them.  But it also - and I think it’s a very good thing that we begin to be able to take the perspective, the rich psychological perspective of other people.  Because, you know, I’m sitting here with you and, you know, I could - you’re nodding your head and I can’t literally see what you’re thinking, but I have a, you know, pretty good sense that what’s going through your head at this point.  But if I didn’t have a theory of mind you’d just be a body sort of moving about in different ways, and I couldn’t really make a lot of inferences about, you know, how I’m coming across or what, you know, whether or not you’re understanding what I’m saying.

So it was a very good thing, the evolution of theory of mind for our species, but it also came with some dark sides too.  You know, the chapter in the book on suicide.  I believe suicide-

Steve Mirsky:                Right.

Jesse Bering:       -suicide that is initiated by other peoples’ appraisals of us, or other organisms’ appraisals of us is something I think that is completely unique to human beings in the animal kingdom.  That’s not to say that other species don’t sometimes engage in self-sacrificial behaviors and it looks like suicide, but other species typically will - it has to do with parasite transmission, you know, bumblebees going off to die in a flower meadow because they’re infected, they don’t want to infect the rest of their community.  Not that they don’t want to, it’s just heuristic that they’ve sort of evolved.

Steve Mirsky:       Right.

Jesse Bering:       But for us it’s, you know, oftentimes these sort of intense shame, depression, all these really negative self-evaluative emotions requires a theory of mind, because it’s basically taking the perspective of others who are evaluating us, and it’s very painful.  So it wasn’t all good, and, you know, there are dark parts to the book too that show sort of the significant hurdles that we’ve run into, the unique evolutionary hurdles that we’ve run into as a species.

Steve Mirsky:       Do you think that propensity to suicide is the equivalent of say our vulnerability to malaria - I mean to sickle cell disease, in our attempts to fight off malaria by developing the sickle cell gene.  So the suicide is an unfortunate artifact of the theory of mind.

Jesse Bering:       Yeah, I’m not - I don’t know the answer to that question, actually.  Like I can sort of speculate.  And I do think that the suicide-as-adaptation model, which basically argues that many people who kill themselves do so because they perceive themselves, either correctly or incorrectly, as being a burden to their biological kin, so removing yourself has this sort of surprising effect from just that sort of coldhearted national selection point of view, has the strange effect of increasing your genetic fitness because your biological relatives actually are hampered by your physical existence, either taking care of you somehow or you’re somehow interfering with their reproductive success.  You know, maybe you’ve ruined the family’s name, you know, sort of mired the family’s reputation, now that’s the sort of only saving grace to forgive the rest of the family. 

So I think that there’s an articulation between these, you know, mechanical sort of biologically adaptive selection factors, there’s an articulation with that and theory of mind.  It’s the two things that go together that cause, you know, real problems in that sense.

Steve Mirsky:       Mm-hmm.  Well, despite our drift here towards the end of our conversation into Arthur Miller plays-

Jesse Bering:       Yeah.

Steve Mirsky:       -the book is really a lot of fun and most of the material in it is-

Jesse Bering:       It’s pretty light.

Steve Mirsky:       -it’s light, it’s enlightening, and it’s written in a very engaging style.  There’s a lot of funny stuff in there too.  So I really recommend it.  Jesse Bering, great to talk to you.  Thanks for coming in.

Jesse Bering:       Thanks, Steve.  I appreciate it.

Steve Mirsky:       Jesse Bering’s book, Why is the Penis Shaped Liked That? is available through that free Audible.com audiobook offer I told you about at the beginning of the podcast.  Just go to www.Audible.com/SciAm.  To hear a clip from the book read by Jesse himself, go to his website, JesseBering.com.  Jesse’s new book, Perv: The Sexual Deviant in All of Us, comes out in October.  It’s available for preorder now at the usual suspect sites.

We’ll be back right after this word from Kerri Smith at the Nature podcast.

Kerri Smith:         This week the oldest genome ever sequenced, how elephants evolved from tree eaters to grass eaters, and why humans are so good at playing baseball.

Steve Mirsky:       Just go to www.Nature.com/podcast.

That’s it for this episode.  Get your science news at our website, www.ScientificAmerican.com, and check out the collection of Scientific American e-books available for Kindle, the endangered Nook, and iBooks.  You can find them by going to our website and clicking on “Products” on the right near the top, and then on Scientific American e-Books.  And follow us on Twitter, where you’ll get a tweet whenever a new item hits the website.  Our Twitter name is @SciAm.  For Scientific American Science Talk I am Steve Mirsky.  Thanks for clicking on us.

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