Imagine seeing a cockroach skitter across your kitchen counter. Does that thought gross you out? This week, we take an unflinching look at the things that make us say “ewww.” Plus, why disgust isn’t as instinctive as we might assume.
The transcript below may be for an earlier version of this episode. Our transcripts are provided by various partners and may contain errors or deviate slightly from the audio.SHANKAR VEDANTAM, HOST: This is HIDDEN BRAIN. I'm Shankar Vedantam. What comes to your mind when I say the words Hall of Fame? Maybe the Rock & Roll Hall of Fame in Cleveland, Ohio, or the NASCAR Hall of Fame in Charlotte, N.C. Music, sports - these make sense. For today's show, I want to take you to an unusual Hall of Fame. It's in New York City. It pops up only once a year. And it's the kind of attraction you might smell before you see it.RACHEL HERZ: This year, what you're looking at - with all the danger tape all over it - is the Hall of Fumes.VEDANTAM: The Hall of Fumes is located in the Ripley's Believe It or Not Museum in Times Square. To be honest, it's not really a hall. It's a metal rack holding up dozens of tattered, stinky sneakers.HERZ: And these are the winners from all the past 42 years, up until now.VEDANTAM: This is Rachel Herz.HERZ: And I'm here, judging the 43rd Rotten Sneaker Contest as the odor judge because for the past 11 years, I have been the celebrity nose who gets to smell the stinkiest feet in the country.VEDANTAM: Contestants have to be between the ages of 8 and 15.UNIDENTIFIED MAN #1: Let's bring up our first contestant. Come on up.VEDANTAM: The six finalists of the 2018 competition qualified after winning similar contests at state fairs. Rachel is here to judge only the creme de la creme.HERZ: The kids have to actually hand me their sneaker. I pick it up with a pair of tongs because it's - you know, I wouldn't really want to touch it. Even though I'm wearing rubber - rubber gloves, I really don't want to touch it.UNIDENTIFIED MAN #1: Can you tell everyone just how you got this shoe so dirty and rotten?UNIDENTIFIED CHILD: So I play in them a lot. I wore them over the summer without any socks, and...HERZ: So then I take it, and I stick my nose as close to it as I possibly can, which is - I try not to get right in there because I can smell it, usually, from quite far away. And then I sniff, and then I rate it on a scoresheet.VEDANTAM: You might be wondering how Rachel landed this coveted gig. She's a psychologist affiliated with Brown University and Boston College. And she's extensively researched the human senses of smell and taste and the emotion of disgust.UNIDENTIFIED MAN #1: Contestant number three, step forward, please. I will take this. Put your sneaker on the tray.HERZ: Oh, that's horrible.UNIDENTIFIED MAN #2: That's horrible (laughter).HERZ: I have to blow my nose now.VEDANTAM: Now, I don't even have to smell the shoe to feel disgusted. The thought repulses me. That's how Rachel felt too before she judged her first contest 11 years ago.HERZ: I had really, really psyched myself up to think, OK, this is going to be the worst thing that you could imagine. Just don't worry, it's going to be over soon. And when I went to smell the sneakers, they actually - I mean, they weren't good, by any means. But they were not as bad as my mind had prepared me to assume that they would be.(SOUNDBITE OF MUSIC)HERZ: What I realized is that it's our minds that have so much control over what we think is disgusting and how we approach something that's disgusting.VEDANTAM: Today on HIDDEN BRAIN, we nose around the topic of disgust. Why do some things, like smelly sneakers, disgust us, while other things, like smelly pieces of cheese, delight us? And we learn why Rachel calls disgust...HERZ: The instinct that has to be learned.(SOUNDBITE OF MUSIC)VEDANTAM: There's a simple explanation for why we have the emotion of disgust. It's a defense mechanism against things that could contaminate us. But we often have flawed intuitions about how disgust works, starting with what's clean and what's dirty. In her book "That's Disgusting," Rachel Herz talks about how the cleanliness of toilet seats compares to buttons on an ATM.HERZ: Things that we actually touch a lot and have no idea - or don't really think about how disgusting they are - things like ATM buttons, actually our cellphones, are just petri dishes of pathogens and germs. And most of us do not clean our cellphones very often. And yet, we have this idea because of the associations that we know very specifically between toilets and waste from the human body that toilets are really, really filthy. And yet, we don't give a second thought to things like keyboards, or cellphones and other sorts of things that people are touching all the time and could be very dirty and contagious.VEDANTAM: I want to talk about a certain quality that disgusting things have, Rachel, which is that they tend to almost infect the things around them. As the psychologist Paul Rozin, who's done a lot of work on disgust, says, a single cockroach will destroy the appeal of a bowl of cherries. But a single cherry doesn't make a bowl of cockroaches appealing. Why do disgusting things infect the things around them?HERZ: Well, first I want to make - sort of flesh out a point there that I think is really interesting, and that is that good does not overpower evil the way evil can overpower good. And so in fact, in other experiments by Paul Rozin, he found that the idea, for instance, of how could you purify something like Hitler's sweater? So people are told that Hitler owned this sweater, and would you be willing to wear it under varying conditions? Or would you be - when could it become OK? And no form of cleaning could make it OK. Mother Teresa wearing it could make it a little bit OK. But in the case of Hitler's sweater, it had to be totally destroyed and burned in order for it to be OK.So good does not sanctify bad in the way that bad can sanctify good. Whereas just one spot of something bad like a cockroach, for instance, in a glass of water or milk or anything else has the capacity to destroy the whole thing because negativity is much more pervasive and powerful from the way that we are built. And this is, in fact, adaptive because it's better to be worried about things that can harm us than overly excited about things that might be benevolent.VEDANTAM: I remember doing a story some years ago, Rachel, that looked at a slightly related idea. This was a work by the sociologist Anne Bowers, and she was studying the market for used wedding rings. And she found that people were really reluctant to buy a wedding ring when they learned that the couple who had previously owned that wedding ring had gotten divorced. And people tended to want wedding rings where, you know, there had been some tragic love story, but the couple had been very happy together. So I'm not sure if it's exactly the same concept, but it really feels as if inanimate objects can sometimes carry with them the - I don't know - the spirit, if you will. It's an unscientific idea, the spirit of living things.HERZ: Well, actually it is very much the same concept, Shankar. And what you're talking about is something called sympathetic magic, which definitely plays a role in disgust and what we're disgusted by through association. The idea of once in contact, always in contact. So for example, the ring that was on the finger of the woman who had a terrible marriage and ended up getting divorced somehow, even though that ring is now in a jewelry shop, has nothing to do with that original couple whatsoever, the essence of that bad marriage is somehow still in the ring. And therefore, wearing that ring will therefore impart the bad marriage onto the new wearer. And somehow this spirit, as you said, will transcend and infect the new marriage. So it's again - it's a form of infection.VEDANTAM: You have a very simple and interesting thought experiment in your book, which is I'm not disgusted at the thought that when I drink a glass of water that there is saliva in my mouth. But if I spit in a glass of water and then I drink that glass of water, that seems disgusting. And of course, in both cases, it's exactly the same outcome. I have water in my mouth with saliva in my mouth. Why does it feel more disgusting in one case and not the other?HERZ: So that's exactly a great point about the idea that disgust is about the outside coming in and contaminating our inside. So while the saliva and the water is in our mouth, it's inside of us and even just take water out of the equation. Just the fact that you have saliva in your mouth right now, we're all OK with that. But as soon as we spit that exact same saliva that's in our mouth into the glass, and then look at that and then, I'm telling you now you should drink that, it all of a sudden, even though it's only been out in the air for seconds, it has become contaminated by the outside. And bringing it back into our body is now an entirely different proposition. And the fact, also, I think in this case that even though I know it's my saliva, it could be your saliva. It could be anybody else's saliva. Suddenly it becomes equalized with all the saliva that I know is out there that I definitely do not want in my mouth. So if someone, for instance, is talking at you and spitting while they're talking, you know, enthusiastically, we're disgusted by the fact that some spit could touch us. Just like once our spit is outside of our mouth, it becomes much less pleasant to think about taking it back in.(SOUNDBITE OF MUSIC)HERZ: There was a really interesting study done about sharing your toothbrush. And this study found that - so again the idea that, you know, you have something in your mouth that somebody else had in their mouth. And it was found that the person that one would least like to share your toothbrush with is the boss that you don't like...(LAUGHTER)HERZ: ...Followed by - so if you don't like your boss, you definitely do not want to share your toothbrush with him or her. However, the anchor person on your local news station, if they were attractive was pretty fine to share a toothbrush with. And people in your direct family or your best friends were also okay to share a toothbrush with.And so this speaks to two things - one, familiarity and emotional connection, so people in your family or your best friends, you feel positively towards them. You're very familiar with them, and therefore, you sort of feel safe around their saliva. The good-looking person on the television - beauty equals health equals OK. But the person that you dislike or the person who's a stranger is a lot likely to be either more contaminating or because you don't like them - purely because you don't like them. They could be good-looking and you could know they're very healthy, but if you don't like them, then you don't want anything about them coming into you, as in their toothbrush.(SOUNDBITE OF MUSIC)VEDANTAM: Context is key when it comes to disgust. In October 1972, a plane crashed in an isolated region of the Andes mountain range. There were 45 people onboard, most of them rugby players traveling to Chile for a competition. Many passengers died upon impact. More died in the coming days because of the freezing cold and dwindling food supply. In the end, 16 people had to survive more than two months in the mountains. And their story has inspired movies, books and documentaries like this one from the History Channel.(SOUNDBITE OF DOCUMENTARY, "I AM ALIVE: SURVIVING THE ANDES PLANE CRASH")VINCE ROBERTS: (As Carlitos Paez, through interpreter) I said, Nando, there isn't anything left in the storage compartments where we kept the chocolates and the can of sardines that we had. And Nando looked me in the eye and said, Carlitos, I want to eat the pilot.HERZ: The people that had this idea and wanted to convince the other members that this was the only way they were going to survive did two things. One, they told the people to think of this as what you're doing is eating just meat. So don't think about this as a person - kind of connected to we don't think about eating cows and pigs so much as we think of eating pork and beef. So this is just meat.And the second thing is that they tried to justify this in another kind of a moral way by saying that the death of their compatriots was - would have been sort of a complete waste if it couldn't be used in this way to potentially aid in their survival. And so reluctantly at first, but then everybody joined in, ate the dead remains of the people that were around them. And another thing they did...(SOUNDBITE OF DOCUMENTARY, "I AM ALIVE: SURVIVING THE ANDES PLANE CRASH")JAMES LENTZSCH: (As Nando Parrado) We made a pact, and we did what people do now. People give blood to friends, to family members. They make organ transplants, you know? And we made a pact. We said, OK - hand in hand - if I die, please use my body, so at least one of us can get out of here.HERZ: So the fact that this is about cannibalism and that the people willingly resorted to this is something which has really caught our imagination because it really leads to this question of what would you do in that circumstance? Would you also, you know, traverse the line into this worse taboo?VEDANTAM: One of the things that I find interesting is that when I personally think about their behavior, I don't necessarily feel disgusted by what they did in the same way that if you told me that someone was munching on their, you know, neighbor's arm. You know, there's something about essentially having your hand forced by circumstances. You're acting in a way that is the only way you can possibly survive. That changes the way I think about whether this is disgusting.HERZ: Exactly. It's only really disgusting when it's a willful, unnecessary behavior - so like you said, you know, you kill your neighbor and then decide to eat them. But someone who is forced into this situation and the only way that they can survive is by resorting to an opportunistic situation - the person's already dead - that's a lot different. But the act itself - eating someone who's dead, eating another dead human being - is the same. This is how our mind changes the behavior from being OK to something completely abhorrent.(SOUNDBITE OF MUSIC)VEDANTAM: Rachel, you describe a case that took place in the 1990s. A man was stomped to death after propositioning another man. And when the case was taken to court, the defendant successfully used something known as the gay panic defense. You say this idea is rooted in a misconception about disgust.HERZ: So this idea that in this sense, using the gay panic defense - so in this case, someone was able to convince a jury that the idea of this man making a homosexual advance to him was so repugnant that being, you know, motivated to kill this person was somehow justified. And like you said, it actually was successful in the trial.Now, the concept that I think - so this is sort of - this is moralizing, and this is getting people to become less judgmental towards the act of murder because of the fact that they felt a kind of a sympathy towards the feeling of aversion that this person must have had, and therefore, this sort of outburst of rage is somehow justified.The thing that's different about this - and I think this is an interesting point about disgust and what makes it different from anger, which I think it's often confused with - is that disgust is about recoiling from, moving away from, avoiding the stimulus that's making you disgusted. And if someone were truly disgusted by somebody else, they would not want to get all over them and beat them to death and get their blood and everything else all over them because that would be even more disgusting if you're already disgusted. Instead, if I'm really angry, if I'm enraged by something, then I attack, then I approach, then I can, you know, demolish you and get all covered in you, and it doesn't matter because I'm just in a rage.So really the idea about this being disgust is wrong. And what it was is this person was affronted, you know, somehow morally, personally - whatever the case might be - and incited into such a rage that then he wanted to murder this person. So the idea of using disgust in this way is actually flawed.(SOUNDBITE OF MUSIC)VEDANTAM: So that example of homophobia, Rachel, makes me think about an idea. In almost every society you go to, you see patterns of disgust that are modeled on social hierarchies. In many countries, you have the rich who are disgusted by the poor or upper castes who are disgusted by lower castes or people who are native citizens being disgusted by foreigners. What do you think explains this?HERZ: It has to do with something more insidious, and that's related to our feelings about our social environment and the people that are in it. And the idea that foreigners and strangers and so forth are threats to our social normal order and that then becomes somehow connected to our ideas about contamination and protecting us somehow. And the idea is that this somehow justifies and rationalizes racial prejudices and other kinds of prejudices because if we stay away from the familiar - unfamiliar and the foreign because we don't know what those immigrants - you know, they could be diseased, and in fact, disease was often used as a way of anti-immigrant propaganda - this somehow justifies negative attitude towards them when there is no relationship between their ability to actually make us sick or not.(SOUNDBITE OF MUSIC)VEDANTAM: In much of our life, disgust feels instinctive. When we see a cockroach on a kitchen counter or smell rotten food in the trash can, our revulsion feels hardwired. But Rachel says it's not. Our sense of disgust is learned. We explore that idea next.(SOUNDBITE OF MUSIC)VEDANTAM: Psychologist Rachel Herz says the things that disgust us not only reveal a lot about our culture, they reveal a great deal about our minds. She remembers an instructive episode from her own childhood.HERZ: As we were driving in the car, and it was a beautiful, sunny, summer day, and the windows were rolled down and there were - you know, we were going by fields and everything was very pretty - my mother, from the front seat, said, oh, I love that smell. And so, as I was smelling the same thing and all kinds of nice things were in my visual scene and my mother who I love said, I love that smell, I thought, OK, this is a great smell. And I then learned, a few years later, that saying that in response to that smell was a very big mistake. So the smell turned out to be skunk...VEDANTAM: (Laughter).HERZ: ...So when I said I love that smell on the playground with all - a bunch of little kids around me and they went, ew, disgusting, that's skunk, oh, you're so gross, and so forth and ran away from me - again, so I become, now, the skunk because they all ran away from me - I realized that was not the socially appropriate thing to say. And so I kept that to myself for quite a while. But it turns out I'm not alone (laughter). There are, actually, people who like the smell of skunk, and that also leads into something interesting about our sense of smell. In fact, we don't all smell skunk in the same way, so both our minds and the way our noses, in fact, react to the chemical that makes up skunk is different. So unless you have an identical twin, your - your receptors in your nose are actually only yours and nobody else shares them even though there's a lot of overlap.VEDANTAM: So I buy the idea that we're all not smelling the same thing when we smell skunk, that our - the receptors in our noses and the way our brains work - you know, we might be smelling different things. But it's also - what I find really fascinating about the story is that there is so much about disgust that is actually learned. You heard your mother. You have an association between your mother and the beautiful scenery around you, and you learn, in some ways, whether something that's a strong smell is a positive smell or a negative smell. And in many ways, this runs counter to the way most of us, I think, think about disgust. We think of it as being this innate drive that, if I find something disgusting, you're going to smell it, and you're going to find it disgusting as well.HERZ: So I think that brings up a great way to think about the idea of disgust, and it is that it is the instinct that has to be learned. So once we learn what something disgusting is, we then feel disgusted by it. Like, for instance, bodily products and toilet training and, you know, poop and so forth. We don't have a question about whether or not it's disgusting, especially if it's from somebody else where - also is where meaning and context come into play, but we did not think it was disgusting from the get-go. So that is to say, we were not hardwired or born thinking that poop was gross.In fact, many infants both like to play with poop. They like the smell of poop. They don't have any reactions to things, for instance, that adults in the same community think of as positive or negative. In fact, a great demonstration I like to do is showing these facial expressions of babies getting either the smell of sort of sweaty socks and vomit versus the smell of vanilla. And some babies' faces to the sweaty socks and vomit are making big smiley faces, and others to the face - to the smell of vanilla are making what we would call disgust faces.So, you know, there's nothing hardwired about the reaction either to smells or to things that are disgusting, but once we learn what the meaning is, we then stick to it except for when the context can make it very confusing or the context changes the way we perceive something.VEDANTAM: I love this idea that in many ways our notions of disgust are constructed. I understand that Americans like wintergreen-flavored chewing gum but people in Britain, not so much.HERZ: So in the U.K., wintergreen mint is used exclusively in toilet cleaning products and in some medicinal balms like things you would rub on your skin if you're in pain. And so they're connected - the smell is connected to either being in pain or cleaning the toilet - so not good. In the U.S., however, this scent is used in candies and in gums. It's connected to the taste of sweet, and sweet actually is innately positive. So tasting sweet plus smelling something, that's going to be good. And we don't have any connection to cleaning the bathroom or being in pain when we smell this odor.And so, as a function of the connections that we have learned to it and what the meaning is, this odor, which in and of itself, is totally, you know, agnostic, it doesn't have meaning one way or the other, becomes good or becomes bad as a function of that.VEDANTAM: So the British and the Americans are divided on the subject of wintergreen, but I'm absolutely sure they'd come together when it comes to eating bugs.(SOUNDBITE OF MUSIC)UNIDENTIFIED MAN #3: It ain't happening.UNIDENTIFIED WOMAN #1: My heart's pounding. Oh, my God (laughter). They look like crickets. There's no sugar coating.UNIDENTIFIED MAN #4: I'm about to throw up if I stay here.UNIDENTIFIED WOMAN #2: I don't want to do it.VEDANTAM: Those are reactions from a couple of our NPR co-workers when we presented them with a plate of dried crickets and asked them to take a bite.UNIDENTIFIED MAN #5: Can I go fill up my water bottle? Can I have a chaser?UNIDENTIFIED WOMAN #3: I'm cool with bugs as long as they're outside. I'm not sure how cool I am with them being in my mouth.UNIDENTIFIED MAN #6: It's disgusting. It's insects. Look at it, there's exoskeletons everywhere and pieces of legs. This is gross. People eat this?HERZ: There's a couple of things which disgust us about bugs. One of them is that we don't consider them to be food. Now, there are cultures, especially in Southeast Asia, that do consider all kinds of bugs as food. And if you were to go to Thailand, you'd see Madagascar hissing cockroaches on display in the market where people are actually buying them to eat them up for meals and prepare them in all kinds of ways, which apparently, although I don't know personally, can be quite delicious. But the idea of what food is is a really interesting concept because this, again, speaks to how disgust is learned. And when we decide that something is edible, then it's OK to eat, and other cultures think differently about that.The other thing about bugs is that they move in a way that seems to be related to one of the aspects of disgust underlying why we don't like them, and this is actually somewhat connected to bodily fluids. So bugs move in a kind of a jerky or slithery or slimy kind of way. And those kinds of things actually have a similarity to body products that we are also disgusted by. So being disgusted by slugs, for instance, is to do with the fact that slugs are similar, visually, to feces. So there is this kind of continuum about our association between what bugs are and what bodily fluids are that we're disgusted by. So there's a variety of reasons why bugs are disgusting.VEDANTAM: One of the things in your book that caught my eye was even in the same country in different periods of time, our attitudes about what's disgusting have changed or can change enormously. I understand that a few centuries ago, lobster was not quite seen the way that it was in Massachusetts.HERZ: No. Lobster was actually considered vermin of the sea and only suitable for slaves. And, in fact, there was a slave uprising against the idea that it was completely cruel and unusual punishment to give people lobster to eat more than three times a week. And today, we might say, oh, how lucky to be able to afford to have lobster three times a week.VEDANTAM: So it's conceivable then maybe in a few decades, or maybe in a couple of centuries from now, we will think of eating cockroaches and crickets very differently than we do today. In fact, there are some people who would argue that insects are a very efficient source of protein and they're plentiful and in some ways consuming insects might actually be good for the environment in all kinds of different ways. I'm personally a vegetarian, so I don't know if I'd ever subscribe to eating crickets and cockroaches. But presumably, our attitudes towards eating insects could change.HERZ: Absolutely. So the idea also - one of the things that made lobster disgusting and unappealing is that it was slave food. It was prisoner food. So these people, these are bad people in the kind of hierarchy of humans, and therefore it's OK for them to eat things that are possibly that we would consider disgusting but not OK for me, you know, the elevated person or whatever I think of myself as being. And right now, the way we think about insects is similar to that. So people who are not like us, people who have to resort to the, you know, the last measures possible for survival, they're going to, you know, debase themselves to eat insects.But if we think about it entirely differently - so if we re-moralized the story and instead make eating insects about saving the planet and make it a virtuous thing to do rather than somehow a debased thing to do or a last-resort thing to do, we could, in fact, make it a very positive thing.(SOUNDBITE OF MUSIC)VEDANTAM: While some of our co-workers shrank at first when they held the cricket in their hand...UNIDENTIFIED WOMAN #4: The more you look in his eyes, the less you want to eat it.VEDANTAM: ...The looks of fear and disgust faded after the first crunch.UNIDENTIFIED MAN #7: Cheers.UNIDENTIFIED MAN #8: Cheers.UNIDENTIFIED WOMAN #5: They're just like chips kind of.UNIDENTIFIED MAN #9: It's good. It's a little - it's earthy.UNIDENTIFIED MAN #10: It's like sunflower seeds or something.UNIDENTIFIED MAN #11: Yeah, it's like, can I get a basket of these, like, before my meal comes?UNIDENTIFIED MAN #10: Yeah, yeah.(LAUGHTER)VEDANTAM: Along with the whole crickets, we also provided samples of delectable protein bars made of cricket flour.UNIDENTIFIED MAN #12: I chose peanut butter and chocolate.UNIDENTIFIED WOMAN #6: If you didn't tell people this was cricket, they wouldn't know.UNIDENTIFIED MAN #13: It's good.UNIDENTIFIED MAN #14: It's not like there's big chunks of cricket in it, so (laughter) I like it.UNIDENTIFIED MAN #15: Not bad at all.UNIDENTIFIED WOMAN #7: I'm trying to not be so like American, you know? Because, like, everyone else eats crickets.HERZ: It is a luxury to be able to be disgusted from the very basic level that if you don't have anything else to eat other than someone who's dead beside you or the cockroach on the floor, then you just do not get disgusted by that because you have to do it in order to survive. So it's a privilege to be able to say, no, I'd rather not have that dead person or that cockroach. I'd rather have that hamburger or the steak or that beautifully prepared dish of Portobello mushroom.VEDANTAM: You heard it here first. Crickets are the new lobster.(SOUNDBITE OF MUSIC)VEDANTAM: Disgust, in so many realms of our lives, is about our mindset. The things that repulse us in a different perspective can become attractive.UNIDENTIFIED MAN #1: And now (imitating drum roll) drum roll...VEDANTAM: Back at the Rotten Sneakers Contest.UNIDENTIFIED MAN #1: ...The winner of this year's 2018 Odor-Eaters Rotten Sneaker Contest goes to Hunter.(CHEERING)UNIDENTIFIED MAN #1: Hunter, come on up. Stand right here.VEDANTAM: Eight-year-old Hunter Hamm from Eagle River, Alaska, takes home the title, and he adds his shoes to the Hall of Fumes. His mother, Lauren (ph), says Hunter joins a family pantheon.LAUREN: My nephew Connor won last year from Alaska. I don't know if that's what you really want to be known for, stinky feet, but we're having fun with it (laughter).VEDANTAM: Our celebrity judge, Rachel Herz, gives us the expert analysis on the competition results.HERZ: So Alaska is almost always the worst in my experience every year because I think they have so much more outdoor play. And they're usually fishing, which is a really horrible smell when it's rotted. And they're often more farm based, and so they usually have the worst sneakers of all.VEDANTAM: While the competition seems like pure silliness, the kids are actually learning something important. Hunter and the other finalists are getting a master class in what our culture deems to be disgusting.HERZ: So young children are not very good at recognizing disgust faces. In fact, they often mistake the face of disgust with the face of anger and actually adults do as well but not to the same extent. And children actually, again, have to learn what disgust really means. And it's only once they're able to understand themselves the different levels of disgust are they then able to recognize disgust in somebody else. Because when they see disgust, let's say, in the face of an adult, they also recognize that it's in response to something.So just like your parent might make an angry face because you threw all your plate on the floor and was, you know, banging your hands on the table or something like that, they may make a different face if you, you know, pee on the ground, for example. And the idea is that the child has to then make the association between there is something that's just happened in the environment and I'm seeing this face and that's what that face means.VEDANTAM: Right.HERZ: And the connection between that and disgust takes a lot longer to develop than it does between other sorts of things like anger or fear or happiness.(SOUNDBITE OF MUSIC)VEDANTAM: Rachel Herz is the author of "That's Disgusting" and "The Scent Of Desire." She also had a book out at the end of 2017, "Why You Eat What You Eat." Rachel Herz, thank you for joining me today on HIDDEN BRAIN.HERZ: It's been a pleasure, Shankar. Thank you for having me.(SOUNDBITE OF MUSIC)VEDANTAM: This episode was produced by Parth Shah and edited by Tara Boyle. Our team includes Rhaina Cohen and Jenny Schmidt. Field production assistance this week by Monique LaBorde. Our unsung heroes today are the brave NPR colleagues who signed up to eat crickets for our show. They are N'Jeri Eaton, Michael King, Sam Hoisington, Kumari Devarajan, Du Tran (ph), Alex Curley, Alex McCall, Maia Stern, CJ Riculan, Ramtin Arablouei, Adam Winters and Kelly Jones. There was one other NPR staffer who partook of the delicacies we served in the creation of this episode. Producer Parth Shah ate some of the crickets. What did you think, Parth?PARTH SHAH, BYLINE: Not as good lobster.VEDANTAM: (Laughter).SHAH: But, I mean, it was - it wasn't bad. I liked it.VEDANTAM: Did you eat the legs and head and everything?SHAH: Oh, I guess, yeah, just one bite.VEDANTAM: Wow, my God. If you liked today's show, please share it with a friend. If you feel so inclined, like Parth, you can discuss the show over a cricket or two. I'm Shankar Vedantam, and this is NPR.(SOUNDBITE OF MUSIC)STACEY VANEK SMITH, BYLINE: Sometimes the economy is kind of hard to understand or, you know, not that exciting, but not on Planet Money. You can think of our show as a guide to business and the economy except it's fun and exciting. Planet Money - find us wherever you found this podcast. Transcript provided by NPR, Copyright NPR.