Stuff You Should KnowWhat is it that makes us suddenly draw in a deep breath through a wide-open mouth? The beautiful thing about yawning is that researchers really don't know. Whether the answer is physical, mental or even contagious there is pretty much no chance you won't yawn during this classic episode.
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M Hey everybody, it's me Josh, and for this week's s Y s K Selects, I've chosen what makes us yawn? It's actually a really good question about something everyone does, and yet we don't really fully understand. After all of these eons of people yawning and all these centuries of science studying things like people yawning, we still can't explain what yawning is. So buckle in and enjoy this episode of Stuff You Should Know. Selex, Welcome to Stuff You Should Know, a production of My Heart Radios How Stuff Works. Hey, and welcome to the podcast. I'm Josh Clark with Charles W. Chuck Bryant. You're getting comfy. Yeah, okay, well you put the two of us together, and this is Stuff you Should Know the podcast. Frank was squeaking. I thought I was in Frank. Was that Frank? Yeah? I was sorry, I'm in Francine. Okay, sorry Francine squeaking, You are in Frank? Who are you? Let's build a chair? Uh? People have never heard this or like, what are they talking about? They've already turned off. We name our chairs people then, and everyone he named cars, boats, and chairs. Yeah, a surprising amount of people named chairs. If you don't, you should be paranoid because people are talking about you. It's right, um, chuck, Yes, have you ever oscitated? I have, I've even uh pendiculated. Do you pendiculated before? I pendiculate every morning? You know what we we sound like? Um people running for the Senate in nineteen fifties Florida. Yeah, there's like Florida has a rich history of um like people running for political office using technical terms for things that sound way worse than they are to like smear their opponents. Really. Yeah, there's this one guy who went and I can thank Uncle John and his bathroom readers for um who went after his opponent and said that his sister was a thespian in New York and like all these people are like boo boo. Yeah, and apparently like the smear campaign was successful. That wasn't the only one, but this guy used that a couple of couple of technical terms. We should probably tell people what we're talking about, right, because you said you pendiculate every morning, easily every morning, and that is a what that is a yawn and a stretch combined together. And as one of my favorite things to do in the morning it is. Did you did you see that painting of the It was a self portrait, the artist's self portrait sounded like it was from like the sixteenth or seventeenth century of him pendiculating. It's just as awesome oil painting of this, you know, Renaissance man stretching and yawning. Yeah. I love it because it feels good and it uh, it ties me to my pets, you know, because like I see them do it, they see me do it, and I'm kind of like, hey, we all eat, we all pee and poop, and we all pendiculate. My little cattle stretching yawn. My dogs will stretching yawn, and I will stretching you. So do you guys make one another stretching ya on? You know, I'm gonna start looking out for that because I have not noticed that. But apparently yawning can be contagious to animals, right, Yeah, there's a fun little game you can do jogs supposedly chimps for sure, but probably not cats, I don't know. Yeah, just because it's not in here doesn't mean it's not true. Um, there's a fun little game. You complain the next time you're hanging out with people if you feel like manipulating them on a biological level, Um, just yawn and just start paying attention to how many people yawn as a result, and it should start some sort of chain reaction among maybe of the people, because that's the that's the statistic of how many human adults yawn in reaction to seeing somebody on, seeing video of somebody on, hearing about somebody yawning, reading about yawning, Like how many times did you yawn while you read this article? A bunch? And people will probably yawn while listening to this, Supposedly it's pretty much impossible not to. Yeah, do you ever? This just really shows how deeply disturbed I am. I will not I will suppress or cover up a yawn if someone else has made me on sometimes just so I don't give them the satisfaction. Oh yeah, I've done that before. Sometimes he was like, no, I'm not like just some stranger on an elevator. They'll yawn and I'll just be like, Nope, not me, buddy. One of those people who don't realize that, like they're they're just your mortal enemy for no real good reason, when in fact they really don't even know exists, right, they're like some guys on the elevator, right, So yawning is involuntary. Um, And I've seen a range of of weeks that a fetus has been observed yawning from eleven to twenty and uh, that sort of disproves one of the well many things, disproves one of the theories, which is that we yawned to oxygenate ourselves. Yeah, because a lot of people think that fetus is um, breathe amniotic fluid in the womb, and that is absolutely not true. The oxygen to the umbilical cord. Yeah, so they're not clearly not yawning to oxygenate themselves. Right, And we'll debunk that with other things in a minute. Sure, Um, but that's still it is a little bit of a mystery though, Like, yeah, the other the other ideas for why we yawned don't really hold up in the fetus either. It feels like that's where the key to the mystery of yawning is going to be found in. All right, should we go there over some theories and well, hold on, first, you're saying it's involuntary. I found this one thing, Chuck, that there's a type of paralysis like a lesion on the brain where you can still if you yawn, you still pendiculate, So like you're paralyzed arm. If you yawn deep enough, will will raise, will rise. Yeah, pretty weird. Huh. There's only been a few cases of it over like the last hundred and fifty years, but it's been documented in a number of different places. Yeah, but that is such a surprise. Yeah, seriously, they're like, can I be tired more often? Um So when you yawn, just physiologically speaking, you're gonna open your mouth. You're going to suck in air into your lungs. I read one place that you your eyes usually close. They did this big study and found that most time your eyes closed. But I don't think it's like all the time. You know that's sneezing you're thinking of. No, they did a study on on the eyes of the yawner. Well that's part of the yawn too, as far as um queues go, Like, it's not just the mouth opening your eyes quint. Yeah, and I found like the really good deep yawn, um, my eyes will generally close. So you're gonna flex your your abs. It's good workout. It's gonna put your dye for RAM down. You're gonna fill your lungs with air and then exhale and that as a yawn stretch, you're pendiculating. UM. Also, parts of your brain become active, right. UM. Basically what happens when all of this, when you go through all this process, a bunch of neurotransmitters and dopamine are activated. And that is why a guy named Robert Provine thinks well. He says that, UM, yawns are basically a part of a change from one state of arousal to another. Yeah, like I was asleep, now I'm awake, or I was I was alert, now on board, or I was like just ho hum, and now I'm like in the mood because there you can yawn when you're sexually aroused. So that mood, YEA, the mood, the mood, the Glenn Miller mood. That's what they had to call it back then, and that's what we have to call it today on this family friendly podcast. UM. What's going on to is physiologically speaking, as we are distributing UM, something called the surfactant, which sounds gross and it kind of is. It's a wedding agent. Uh. To cote al violi in the lungs. Um. But are they saying that's what happens or that's why it happens, that's what happens. Okay, they're not saying the reason is to cope the alboli with surfact then, right, it could be. I mean, for all we know. No, we still have no idea what function yawning provides. Same with the the yawning as a symbol of arousal or is a sign of arousal. They think that it's really just a byproduct of it, you know. Okay, but it explains why people who are nervous or dogs. I'm sure you've seen dogs who are nervous and they yawn and like that really kind of weird, unsettling ways when they're super worked up. Yeah. Yeah, and humans too, you know, like people will yawn when they're nervous. It's it's it's it's a sign that you're in a state of arousal. And what that state of arousal is depends on the situation. Yeah. They point to Olympians who yawned before like a race, and um, which Poopoo's one theory that we're going to get to the theory. So we just get to the theories. Let's get to the theory. Poops. That theory though, that you have to be bored or you have to be sleepy retired. Yeah like that. There's the boredom theory, and it's kind of been pretty fully shot down just by you know, just casual observation. There's also the physiological theory, which is that this is the one that I'd always heard when I was younger, like, why are you yawned? Is because you needed your oxygen deprived or you have an abundance of carbon dioxide. So you're drawing in a bunch of oxygen and like putting out a bunch of carbon dioxide. That's why you're yawned. And provine or provine that you mentioned. Yeah, he tested this one right, Yeah, pretty simply. He just said, okay, well, um, let's just give some athletes a bunch of oxygen and see if they um, if they breathe, if they yawn any less than they didn't. He also um increased the carbon dioxide in the ambient air and people still kept yawning. Okay, so that one's gold, but they didn't yawn anymore. Yeah, so we can put that to bed. Yeah. Plus also there was a terrible um hy proof associated with that hypothesis that that explains why people yawning groups, because when you have a big group, more carbon dioxide and less oxygen, and that's like you're all fighting over the oxygen. Right, So you're there yawning. Yeah, whoever can yawn the deepest lives? That doesn't sound right. Evolution UM could play a part. Some people think that maybe we used to yawn took took Wood yawn to bare his teeth to intimidate folks around him UM, or that it developed as a signal. Took Took would give a signal to his mates that hey, we gotta we're hunting now and we need to go now gather would so I will yawn to tell you that like pre speech, right, Yeah, like a bird turning if the whole flock. Yeah, that makes a little bit of sense, But I still don't believe that one. I'm with the brain cooling theory. That's like the most recent one and it seems to be the one that people are subscribing to. Ye. Scientists generally are leaning toward the fact that UM, when our brains are warmer, yawning might cool it down in A cool brain is a more whatever, a better brain. I guess I should say I just better for thinking I just yawned, did you I did? Okay, I didn't see it. Well, I covered my mouth. You might have thought I was purpening. I think I did. Um. So the brain cooling theory, that's the one that most people think is lately, that's the that's the explanation to your yeah, um. And there's another piece of research that people are going into that um is the idea that contagious yawning is the result of empathy, right, that you that you empathize, The more you empathize with other people, the more susceptible you are contagious yawning. And we said earlier that like I think of human adults, UM are susceptible to contagious yawning, right, which the MythBusters confirmed by the way. Okay, so there is some sort of link between what we perceive his empathy and the susceptibility to yawning. When you see somebody else yawning or reading about yawning or whatever, I wonder if it's like a boy, that guy's tired and just let me make him feel better. Well, the pro vine again, he's like really into yawning research. Um. He he has done m r I scans where he shows I guess pictures of people yawning or talked about yawning and you know they yawn um. And when they do, he says that mere neurons go off friends, right, So are our mere neurons are activated when you see somebody else yawn? And apparently that triggers the yawn. But people take it a step further in this quest to prove that empathy and contagious yawning are you know, want work hand in hand and saying, well, then people with autism that that they shouldn't be able to to be susceptible to contagious yawning, right, because they're known to have less empathy, right, they had trouble connecting with others or um, they have trouble developing what's called the theory of mind about other people. Um. And there have been a lot of studies about whether or not people who are people who have autism are contagious? Is too susceptible the contagious yawning? Yeah, and it's it's it's been proven, not proven, but at least. The data says that the more, uh, the the stronger your autism, the less you will yawn, even though uh they will yawn when someone is pretending to yawn. Was that what it was? Yeah? I think it said that, Um, when they're watching video of people just moving their mouths, then non autistic kids yawned more than kids with autism when it was really yawning. Does that make sense? Yes, Well, hold on before we get to that, um, because this is like a whole thing to me, the idea that if you have autism you're not susceptible and contagious yawning. Let's let's first I have a message break from our sponsor. Okay, Josh, So I believe we were talking about autism and yawning, which is I just learned a thing for you. Well, yeah, you said that there was. Um. They have found that if you have been diagnosed with autism, you're less likely to be susceptible and contagious yawning. And they found that the higher on the autism spectrum you fall, the less lucky would you would even be right? Yeah, which would suggest that there is that link because they've tied there there's a link between uh, empathy and an autism and empathy and contagious yawning. So this autism and studying kids with autism is kind of like the fulcrum. So yeah, it just seems to me to be kind of Um, I don't know, I don't I don't buy all the studies that have been carried out. Another studies kind of contradicted, like they other studies have shown that like kids with autism focus on people's mouths rather than their eyes, So maybe they're missing the cue. Member. We said that your eyes scrunch, so like a yawn is not just people opening their mouths. It has all these other facial characteristics that might trigger a yawn and another person. So maybe kids with autism are simply missing that. So you're saying, maybe the data could be skewed by other factors. It could be plus. I just remember when I wrote this article like years back, I was kind of like, yeah, it's just it seems just slightly off, like, yeah, you got a good gut though, Well thanks man, I've been working on it so bad. Um Well, we should also mention too that this goes back a long way, like I believe was it Hippocrates? Yeah, was the first person to start sort of postulating ideas, and he was like, uh, he thought it was fever related, like sickness. It could help cure you. So I got a fever and the only prescription is more yawning. That's why here's the father of medicine. That's right, because he was the first guy to just start saying stuff. But you know that was pretty quickly disproven. Right. But um, the idea that yawning has something to do with um increasing our alertness and awareness, which is kind of one of the current views of yawning. Um that dates back to the seventeenth and eighteenth centuries. Yeah, well it increases your heart rate during inhalation only um, not during uh the I think it it It increases and then levels off and then just drops back down to the more pretty quickly, I got you. Yeah, but up to like thirty beats per minute increase. Right. Yeah. I read a real heavy article on this study that really just made my eyes cross. But that was a long and short of it. Right, But that's one that dealt with the eyes, Like they really measured all kinds of stuff. Uh. And when we said that fetus is from eleven to twenty weeks of development yawn in utero and did you see any of like the four d ultrasounds of fetus? Is yawning? Is it adorable? It's pretty cute, but it's also weird at the same time because they're not fully developed. It's it's like, oh you, it's like a little baby platypus kind of um, but you have to be around age four before you um can Uh, you're susceptible the contagious yawning. Yeah, it's there, any way to put it besides susceptible the contagious yawning, I don't think so. Do you feel like you've said that like a lot and I've had trouble with it every time. Uh. There's another couple of researchers who a couple of years ago, um Andrew Gallup and Omar Tansi Elda car H. They found that outside temperature could affect the amount of yawning. So if it's warmer than usual, then you're gonna yawn less frequently because um. Their explanation is the outside air is useless to the organism because it doesn't need to suck in more oxygen. I don't get how the temperture would affect that though. Well, if it's warmer temperature and you're using the cooler air to cool your brain, if it's warmer than the temperature of your brain, then okay, that makes sense. Yeah all right. Well they had other tests though, that's that showed that the amount of yawning increase both when outside temperature and the temperature of the brain increase. Yeah, it's all over the place. No, no one knows anything about yawning except Robert Provine, the foremost leading authority. Well, well he's proven that like seeing your hearing about somebody yawning, it triggers your mirror neurons. So yeah, I think somebody should do a documentary on these people that become obsessed with yawns. No, just like a certain small thing. So you're yawning right now? Um, And that was unsatisfying because you made me laugh in the middle of it. I think like fast, cheap and out of control. I've talked about it before. Errol Morris's documentary sort of did that, but that was about like studying naked mole rats or lion taming or um what's it called when you clip the hedges in diopiary gardening. But someone they should do things that are even more like mundane, like this dude that has dedicated as life to yawning. I just think they'd be interesting, Like what drives provine? Figure this out? When it really doesn't matter, you know what I'm saying? Well, I don't know, because and it's not just yawning. He he frequently is cited as a yawning expert. He's an evolutionary biologist. Okay, so like, but yawning, since it's involuntary, and since you find it in all vertebrates, it kind of gives some peek into our evolutionary past. Plus, he probably just loves a good mystery. Sure, he had a great quote too. We were talking how arousal yawning is a is a byproduct of a state of arousal. He was saying that he believes that um, yawns and orgasms share a neurobehavioral heritage. Yeah, so, like they're possibly rooted in the same behavior. Like remember you said it yourself, when you pendiculate feels good, same, you know with the orgasm. Yeah, so I've heard those feel great, right, So possibly if you trace the lineage of this behavior back far enough, you'd see like, oh, they both came from when humans juice to stub their toe. They thought it was awesome, and then the things diverged into these two things interesting into uh, yawning and what happens when you're in the mood the Glenn Miller mood. Right, Ah, you got anything else? No, man, that is yawning forever until somebody figures it out. It's a mystery. Yeah, and I kind of like it like that, But at the same time, I think it's it's so amorphous that there's no no one has a clue. Like sometimes we've talked about stuff that science couldn't fully explain, but we almost always like pick a theory, like this is the one. It just hasn't been proven yet, right, this one. I don't feel like we did that, Like we both like the brain cooling one, but it was kind of discarded. Yeah, and I'm definitely gonna keep an eye on my pets, um, But then I don't know if like, can you induce that just by noticing more, you know, you know what I'm saying, or maybe what I'll do is I'll watch Emily around the pets so no one's in on it. Just be careful, you don't accidentally change their behavior just by observing it's Buckley farts every time he stretches too. And see that's what I'm saying. We'll see if Emily farts while she andiculates, right, that'll be the death's nice. Um. So okay, I think if you guys want to learn more about yawning, you can type that word into the search bar at how stuff works dot com. And since I said search part means it's time for listener mail. Uh, not quite yet, my friend. We have a quick word from our sponsor again, and then we will we have a great listener mail though about Rodriguez. So oh yeah, yeah, okay, all right, so this is a time for message break, okay, and no, it's time for listener mail. Huh yes, And I already gave it away because I wanted people to stick around for this and it is called I hang Out with Rodriguez. So we mentioned Rodriguez, the singer songwriter from the sixties who, unbeknownst to him, was a huge, huge hit in South America. And no, South Africa, what did I say, South American? It's such an idiot now South Africa. And then like down there once on the left ones on the right and then later in Australia and um so we covered that in our Apartheide podcast and you can see the documentary searching for Sugarman's Super Interesting. Which one best documentary this year? Right? Yeah? Yeah? Have you seen How to Survive a Plague? That was up for Best Picture too, best Documentary? Yes, it was a good Yeah, it was really good. Um it was. It's about the early gay like AIDS awareness movement and like it's just what they were up against. His mind boggling, you know, like that society was just kind of like, no, God's punishing you. Good luck with it, pal, jeez. Yeah, it was really something. I saw our friends Steward of Superhuman Happiness. Who are they're fans of the show. He scored the soundtrack. Oh nice, he did a really good job with it too. You want to check that out. Um. I saw another trailer the other day for a documentary about this family of Jews who hid in a underground for a year and a half during World War Two and they never told their story because they didn't think anyone believe it. In this caving cave diver not cave diver, caving guy found these human objects and traced them back to this family and they came out like the surviving ones, like told their story of his amazing it's called No Place on Earth, and uh, it's coming out soon. It looks awesome. All right, Well, there you go, everybody. We like to recommend documentaries around here. Okay, Rodriguez, guys. It's so fun to hear you talk about Rodriguez because I've known him a little bit here and there. I'm glad he's getting recognition. And here's a story about the first day I met him. September two thousand seven, I moved into a one year old apartment building in the Cast Corridor neighborhood of Detroit. It was a bar across the street called the Bronx, and after getting moved in, my boyfriend and I went over there, had a night of celebrating and talking with some old and new friends. Our friend Dale pointed out this dude wearing all black with sunglasses on, said, you know, Rodriguez, that guy over there is bigger than Elvis in South Africa and Australia. I didn't understand the gravity of a statement at the time, but being friendly people, we talked late into the night with Dale and Rodriguez the bar clothes. We decided to walk back across the street to our new apartment, and Rodriguez followed us out with his guitar and toe. It's very quiet out about three in the morning. The apartment building was you shaped, with a big courtyard in the middle and low lighting. It was really beautiful. There was a single picnic table and we sat there on it, talking more and more. Rodriguez pulled out a pint of brandy, offered us some and then asked if we wanted to hear his new song, saying he had just written it the other day. He said sure because he seemed so incredibly excited about it. He played the song for us and played it again, which I thought was interesting. He played it twice, So did you like that? You want to hear it again? Wait before you answer, let me play it a second time. Uh. And then we talked some more about music and love and he played it once again. No way, I guess he played it three times. Um. I saw many many times over the next few years and met his middle daughter as well. He'll played the same song every time. But I'll never forget sitting under the stag stars all alone with him in a majestic old Detroit courtyard giving my boyfriend and me a private concert of a single song. That's cool played Thrice in passing the Cheap Brandy. He really is. It's kind and happy of a soul, as the movie says, that's cool. When you watch Churching for sugar Man, you can see a couple of people talking to the Bronx bar and even see my old apartment in the background. I hope I see you guys soon, Love Julia. Well, thanks Julia. Hat tipped to you for being aware of the word Thrice, and for um, I guess waiting out the storm in Detroit. Yeah, and for listening to that song three times like very patient understanding with the smile plastered on your face the last time, Like yeah, very cool memory, I imagine. Yeah. Um, let's see if you have a story about any so famous singer, songwriter, filmmaker. Anybody remember the guy who hung out with Henry Hill and became like really disenchanted as a result. Yeah, yeah, if you have a good story like that, We're always in the move for a good yarn, especially if it's true. You can tweet to us if it's a really, really short story um to s y s K podcast. That's our handle, the whole thing um. You can join us on Facebook dot com slash stuff you Should Know all one word. That's our Facebook page. You can send us an email to stuff podcast at how Stuffworks dot com and has always joined us at our home on the web, Stuff you Should Know dot com. Stuff you Should Know is a production of iHeart Radio's How Stuff Works from More Podcasts for my heart Radio because at the iHeart Radio app, Apple Podcasts, or wherever you listen to your favorite shows
