Selects: How Dopamine Works

Dopamine is perhaps the most talked-about, most misunderstood biochemical in our bodies. It’s linked to not only addiction and depravity, but also focus, motivation, and living a productive life. How can one molecule be so many things to so many people? Find out all about it in this classic episode. See omnystudio.com/listener https://omnystudio.com/listener for privacy information.

Speaker names marked ? are inferred from speaking time and the show’s known hosts — they are not voice-verified.

• 0:00Speaker 00

  This is an iHeart Podcast. Guaranteed Human.

• 0:04Josh Clark?

  Buy smart, drive for less and trade for more. That's Toyota affordability and it starts with a great deal on an off-road ready Tacoma or half ton Tundra, two of Toyota's longest lasting trucks, combining power for work, tech for adventures and style in between. And they're built on a reputation for quality and reliability, which is why Toyota trucks are known for holding their value, which could mean big savings when it's time for your next Toyota. So get a great deal today and a great value tomorrow. Shop toyota.com for more. Toyota, let's go places. With no fees or minimums on checking accounts, it's no wonder that Capital One Bank Guy is so passionate about banking with Capital One. If he were here, he wouldn't just tell you about no fees or minimums.

• 0:45Josh Clark?

  He'd also tell you about how Capital One cafes are open seven days a week to assist with your banking needs. Yep, even on weekends. It's pretty much all he talks about, in a good way. What's in your wallet? Terms apply. See capitalone.com slash bank guy. Capital One, N A, Member FDIC.

• 1:03Speaker 02

  Hey, everybody. Happy Saturday. Chuck here with a curated selects episode in which we bring out a classic from dusted off from the old dustbin. So you can give it a listen. This one is called How Dopamine Works and it's one of, obviously, one of our more sciency episodes and I managed to struggle to get through it because you know, I'm not good at these, but it was a great episode, so I hope you like it.

• 1:30Speaker 00

  Welcome to Stuff You Should Know, a production of iHeart Radio.

• 1:40Josh Clark?

  Hey, and welcome to the podcast. I'm Josh and there's Chuck and Jerry's here too. The three amigos back together again after some massively triumphant live shows.

• 1:51Speaker 02

  Yeah, we did our little northeast spring swing.

• 1:56Josh Clark?

  Yeah.

• 1:57Speaker 02

  And it was great. It was a good show.

• 1:59Josh Clark?

  Which one?

• 2:01Speaker 02

  The podcast topic that we did, that we did live.

• 2:04Josh Clark?

  Oh, I got you.

• 2:05Speaker 02

  That we're doing all year.

• 2:06Josh Clark?

  I got you. It was pretty good. I love that, that topic.

• 2:09Speaker 02

  That's what you call an on sequitur.

• 2:11Josh Clark?

  But it does feel good to be back, doesn't it? Back in the studio, back doing what we're born to do.

• 2:18Speaker 02

  I kind of prefer on stage, but sure, this is great, too.

• 2:21Josh Clark?

  Do you? You like the thrill of the audience, the roar of the crowd, that bull running at you?

• 2:26Speaker 02

  Yeah.

• 2:28Josh Clark?

  Nice. I like it, too, sometimes when I'm not totally terrified because I drank too much energy drinks.

• 2:36Speaker 02

  Well, I wonder if your dopamine receptors are functioning as they should.

• 2:39Josh Clark?

  Yeah, that's a great question, Chuck. And it's a wonderful segue, too, because it just so happens that today, the topic of this episode is dopamine. And there's probably no more misunderstood neurochemical, certainly neurochemical, maybe substance in your body at all than dopamine. We used to think we had a really great handle on dopamine and what it does and how it works. And it turns out that we are, at every turn, a new study comes along that says, nope, we're wrong. Yep, we're wrong about that. Well, what about, yep, wrong about that. Basically, everything we know in popular culture, and I mean, if you even go on to like Cleveland Clinic

• 3:18Josh Clark?

  website, or WebMD website, or Harvard Health has some articles, you'll see this old antiquated, outdated view of what dopamine is being kind of paraded around, the idea that it's a pleasure inducing chemical, that if something gives you pleasure, you're responding to a hit of dopamine, and that is just absolutely not true.

• 3:41Speaker 02

  Yeah, and this may be the most oft-covered Stuff You Should Know thing that hasn't gotten its own title yet.

• 3:49Josh Clark?

  Yeah. Man, dopamine is the reigning champ right now.

• 3:54Speaker 02

  Yeah, we talk about this stuff all the time, it seems like.

• 3:58Josh Clark?

  Yeah, we do, because it comes up a lot. And the reason why is because it turns out it has a lot to do with more than just pleasure. Like, everybody, yes, it is associated with pleasure, just not the way we've thought for very long. And it does a lot of other stuff, too. Essentially, what it does is it signals things. It says, hey, you behave, or you act up, you stop behaving, something like that. I'm not quite sure exactly what it says. I don't speak dopamine. But it's a neurotransmitter, so it's a chemical messenger in the brain at base. But it's associated with so many different things that, of course, dopamine comes up all the time in our podcast.

• 4:38Speaker 02

  It sure does. So it is, like you said, a neurotransmitter, one of more than 100 of those bad boys functioning in our bodies. And it, like you said, it lets things communicate. It's a facilitator. But it's, it gets all the press for its, you know, like the feel-good stuff that you mentioned, addiction behaviors, whether it's gambling, or drugs, or, or the thrill of, you know, those people that walk around on ledges and stuff.

• 5:10Josh Clark?

  Ledge walkers.

• 5:11Speaker 02

  Yeah, ledge walkers. But it does all kinds of things. That's just where it makes the newspaper headlines.

• 5:20Josh Clark?

  Right.

• 5:21Speaker 02

  But we should probably talk a little bit about just the neurotransmitter cycle that it goes through.

• 5:27Josh Clark?

  Sure. So the whole thing starts, it turns out that dopamine is used throughout the body, but the, in, for the most part, it's used in the brain. The problem is, is if you like, had a big handful of dopamine and you just shoved it in your mouth, it couldn't make it into your brain for use. It can't cross the blood-brain barrier, in other words. Fortunately, the thing that makes dopamine up, its essential ingredient, tyrosine, an amino acid, can cross the blood-brain barrier. And when it gets there, it gets a big fat hug from something called tyrosine hydroxylase. And that converts it into dopamine. And all of a sudden, your brain's like, yes, let's go.

• 6:12Speaker 02

  That's right. And we've known about it a long time, it's been around a long time. It is not exclusive to human beings.

• 6:21Josh Clark?

  No, that's a big one.

• 6:22Speaker 02

  Yeah, it's in all, all kinds of animals. But we are really kind of great at making it. And I was about to say hooked on it, but that implies the whole addiction thing, and I don't want to go down that road. But humans love the stuff, and we produce about three times as much as other primates do.

• 6:41Josh Clark?

  Yes. And in fact, Emily Deans wrote a article in 2011, I think on Psychology Today. She's an evolutionary psychiatrist. And she said that dopamine is what made humans so successful. And from what I can tell, the latest research about dopamine is that it essentially is what allows us to learn about the world around us. We make connections that collectively form our mental map of the world, of how we're to behave around other people, of how we do things like go get food. Like, that dopamine is somehow behind all of it. And that because we're so responsive to dopamine, and we produce so much dopamine compared to other animals

• 7:24Josh Clark?

  in the animal kingdom, that is conceivably what has allowed us to become as successful as we are compared to other animals. Isn't that nuts? Like, it could all just come down to dopamine, essentially.

• 7:39Speaker 02

  Yeah. Opposable thumbs, maybe?

• 7:43Josh Clark?

  Yeah, sure. But I mean, what are opposable thumbs if you can't have, get the wherewithal to move it?

• 7:49Speaker 02

  True. But if you had the wherewithal to move it and you couldn't grab something, you'd probably be pretty straight.

• 7:54Josh Clark?

  You can use the heels of both hands, just like a thumb.

• 7:58Speaker 02

  Are you underselling the opposable thumb?

• 8:00Josh Clark?

  Yes. I'm sick of the opposable thumb always hogging the spotlight. It's dopamine's time.

• 8:05Speaker 02

  You can get those removed, you know. See how you do.

• 8:08Josh Clark?

  I guess, like, that sounds like a dare to me, Chuck.

• 8:11Speaker 02

  Say goodbye to your tennis game.

• 8:13Josh Clark?

  I can play it just by holding the racket with the, both heels of my hand.

• 8:17Speaker 02

  Or I guess we should have said pickleball. That'd be more current, right?

• 8:20Josh Clark?

  I don't play pickleball.

• 8:21Speaker 02

  I haven't tried it yet. I want to, though.

• 8:24Josh Clark?

  Okay. Well, there's plenty of places and people to play it with.

• 8:28Speaker 02

  Yet I have found no one or no place.

• 8:31Josh Clark?

  Oh. I'm sure somebody will write in an offer to play with you.

• 8:35Speaker 02

  Of course. And then I go out there and I like, blow my ACL or something.

• 8:39Josh Clark?

  Oh, God.

• 8:40Speaker 02

  That was nice. So, at the highest level, you know, we kind of talked about this a thousand times before, but dopamine functions as a neurotransmitter. It enables signals to pass through these, these gaps, these synapses, and make connection from neuron to neuron. And that's just sort of the bird's eye view. But there are all kinds of things that dopamine does, and depending what kinds of neurons it's talking to and it's introducing to one another, it's gonna have different effects on the human body.

• 9:13Josh Clark?

  Yes, so there's D1 to D5, I think, types of receptors, dopamine receptors, and four pathways that they follow. And like you said, depending on what receptor is being activated and what pathway is being followed, all sorts of different stuff can happen. Dopamine is associated with motor control, learning, memory. Malfunctions in it can result in psychosis. They use dopamine as a vasostimulant to treat heart conditions. It has just a cluster of different effects on the body depending on where it's being processed, like what pathway it's being processed, right? And I think I said there's four of them total.

• 9:55Speaker 02

  Did you want to talk about those?

• 9:56Josh Clark?

  I feel like we should.

• 9:58Speaker 02

  Okay. The first one is the nigrostriatal tract.

• 10:02Josh Clark?

  Nice.

• 10:03Speaker 02

  You mentioned motor control first, and that's the tract that has to do with motor control.

• 10:07Josh Clark?

  Yeah, so if those aren't working correctly, the one that the dopamine neurons or the dopaminergic pathway in the nigrostriatal tract, that can result in Parkinson's. It's very famously associated with dopamine for anybody who has read Awakenings or saw the movie.

• 10:26Speaker 02

  Yeah.

• 10:27Josh Clark?

  Which we'll probably talk about a little bit more later.

• 10:31Speaker 02

  That movie?

• 10:32Josh Clark?

  Yeah.

• 10:33Speaker 02

  Okay.

• 10:33Josh Clark?

  I got a great, great bit up my sleeve.

• 10:36Speaker 02

  Okay. The second pathway is the mesocortical pathway. That has a lot to do with executive functioning.

• 10:43Josh Clark?

  Yeah.

• 10:44Speaker 02

  Prioritizing stuff, how your brain plans things, how it files away stuff, and how it, you know, how it organizes your overall sort of priorities.

• 10:55Josh Clark?

  Yes. And now it's time to talk about the most random dopaminergic pathway of all, the tuberous and fundibular pathway. Tuberous and fundibular. Yeah.

• 11:09Speaker 02

  I think you had it right the first time.

• 11:10Josh Clark?

  Okay, we'll edit out the second one then.

• 11:13Speaker 02

  All right.

• 11:14Josh Clark?

  I'll put in a slide whistle over it. So that connects the hypothalamus and the pituitary gland. And it's, from what I can tell, I was like, well, what else does it do? It's sole, the sole role of this pathway is to block the production of milk. Or to, yes, to, to prevent the production of milk in the female breast of mammals. That's what it does. That's that, well, it's that pathway's role. And if you block that pathway, the milk production begins. Isn't that interesting?

• 11:44Speaker 02

  Yeah, we talked about that in the two parter, the old breastfeeding two parter.

• 11:48Josh Clark?

  Oh, we did?

• 11:49Speaker 02

  Oh, yeah.

• 11:50Josh Clark?

  Oh, I don't remember that.

• 11:52Speaker 02

  Yeah, yeah.

• 11:52Josh Clark?

  Wow, you got a great memory.

• 11:55Speaker 02

  No, I have a terrible memory. I know you're making fun of me. There's, there's also the mesolimbic pathway. We've talked a lot about the limbic system in the epis, in many episodes. But reward and emotion, and this is the one where, this is the one that gets all the press. Because this is the one that has to deal with addiction.

• 12:16Josh Clark?

  Pleasure.

• 12:16Speaker 02

  And we're going to talk a lot about reward and how reward factors into how dopamine works.

• 12:21Josh Clark?

  Right, this is the reason why some people get the chemical drawing of, the molecular drawing of dopamine, like tattooed on their wrists. Because they're such, so hedonic and into pleasure. That's why you might see somebody with that, because of that pathway.

• 12:40Speaker 02

  I never heard of that.

• 12:41Josh Clark?

  Yeah, it's a thing. It unfortunately turns out to be a misinterpretation, but it is a thing that people do sometimes.

• 12:49Speaker 02

  Sure. So, you know, we talked about misunderstandings about dopamine. And up until not too long ago, we didn't know a lot about exactly how dopamine worked in the body. And there was a misguided thought that there was something called volume transmission at work, which was you just sort of. Uh, well, you don't flood. We'll talk about artificially flooding dopamine, which is also a problem that resulted from this misnomer. But dopamine just went very slowly. It was not very specific at all. Just kind of washed over the brain.

• 13:25Josh Clark?

  Right.

• 13:26Speaker 02

  And if it made some connections with various neurons, then that was kind of the dumb luck of dopamine because dopamine is just dopey.

• 13:33Josh Clark?

  Right. Here's a great example of just how wrong we got dopamine. It turns out the process that dopamine is excreted and crosses into the synapse and creates like an electrical transmission in the brain is the exact opposite.

• 13:49Speaker 02

  Totally opposite.

• 13:49Josh Clark?

  Of volume transmission.

• 13:50Speaker 02

  Yeah.

• 13:51Josh Clark?

  It could not be more opposite than the idea that it just floods slowly across the brain and whatever it runs into, it runs into. We found that in milliseconds, a precise squirt of dopamine hits exactly the right neuron in exactly the right places, right on the money. That's how dopamine is excreted, the exact opposite of volume transmission.

• 14:15Speaker 02

  Yeah. And we learned that not too long ago, 2018. Medical researchers at Harvard released this paper and said, hey, guess what, everyone? It's the opposite of everything you've been saying. And everyone went, oh, okay. Sorry about that.

• 14:30Josh Clark?

  Sure.

• 14:30Speaker 02

  My B.

• 14:32Josh Clark?

  So after the dopamine is excreted and it does its job, it actually breaks down remarkably quickly. It turns into something, it's metabolized into something called homovanilic acid. Right? And from what I can tell, I don't know what the homo does to the vanilic acid, but vanilla, vanilic acid is the flavor of vanilla. So from what I can tell, if you tasted the, the, the homovanilic acid, which is like the metabolite found in cerebrospinal fluid that we test to see how much dopamine you have in your brain at any given time. It may taste like vanilla.

• 15:12Speaker 02

  Wow.

• 15:12Josh Clark?

  Isn't that interesting?

• 15:14Speaker 02

  It's gross.

• 15:15Josh Clark?

  It is gross. And I don't know also if we said that just 20,000 neurons are capable of synthesizing dopamine, but that's a really small proportion of the total number of neurons we have too. About 100 billion, I think.

• 15:30Speaker 02

  Yeah, absolutely.

• 15:31Josh Clark?

  You want to take a break?

• 15:33Speaker 02

  Yeah, we'll break and we'll talk about, well, what everyone wants to hear about, which is how dopamine and pleasure hold hands with one another.

• 15:56Josh Clark?

  Buy smart, drive for less, and trade for more. That's Toyota affordability, and it all starts with a great deal on a truck from your local Toyota dealer.

• 16:05Speaker 02

  That's right. Make a smart buy on the off-road Ready Tacoma or a half-ton Tundra, two of Toyota's most capable and longest-lasting trucks, built with the strength for the tough jobs, the tech to power your next big adventure, and the rugged style for everything in between.

• 16:18Josh Clark?

  Or discover Toyota's off-road lineup, including the iconic 4Runner and Land Cruiser, designed to go beyond the everyday. And with Toyota's proven reputation for quality and reliability, plus hybrid power on many models, you can get more for every mile and drive for less along the way.

• 16:34Speaker 02

  That's right. And long after you leave the lot, your Toyota keeps delivering with great resale value. So you could trade in for more when you're ready for your next Toyota. From a great deal today to a great value tomorrow, a Toyota is right for you. Shop toyota.com for deals and details, or stop by your local Toyota dealer today. Toyota, let's go places.

• 16:56Speaker 03

  First thought is like, wow, how are we going to do all this? Hey, this is Josh and Chuck from Stuff You Should Know.

• 17:02Speaker 02

  That's Alan Goya, planning engineer at AT&T, and he's talking about Intuit Dome, home of the Los Angeles Clippers, where every seat, screen, phone, and transaction is connected with AT&T fiber and 5G, redefining the fans' experience. And Alan's master plan made it all possible.

• 17:18Speaker 03

  It was going to rival anything that was already built. And that takes quite a bit of people and different teams to all be on the same page.

• 17:25Josh Clark?

  That includes field services manager Drexel Jones. His team made sure it all came together and held up on game day.

• 17:32Speaker 04

  Through what Alan's whole crew designed, we connected the event visitors to the world.

• 17:37Speaker 02

  And after years of hard work and collaboration, it was opening night.

• 17:41Speaker 04

  To actually see the whole stadium light up and data's flowing is a beautiful thing.

• 17:45Speaker 03

  What the fans' experience is incredible. It gave me a lot of pride.

• 17:49Josh Clark?

  AT&T, connecting fans to what they love.

• 17:52Speaker 05

  Connecting changes everything. AT&T.

• 17:58Speaker 02

  You know, you're never done decorating your home. You know what I mean?

• 18:01Josh Clark?

  Sure.

• 18:02Speaker 02

  Yeah, because it's a process. There's always something you could do or buy or update. The only question is, what's next? For us, our animals just wear out our rugs so quickly, it's usually a new rug.

• 18:12Josh Clark?

  Well, Chuck, whether you need a rug or whatever is next for you, you can go to Wayfair. It's the smart place to get it.

• 18:19Speaker 02

  That's right. Whatever your style, whatever your budget, whatever you're looking for, Wayfair makes it easy to find it. And you can feel good about your purchases, too, because Wayfair verified products go through a thorough 10-point quality inspection.

• 18:31Josh Clark?

  And with over 20 million 5-star reviews, Wayfair must be doing something right. You can find pieces made for real life and get even more value with Wayfair Rewards. Join Wayfair Rewards today to get 5% back on every purchase. Head to wayfair.com to shop all things home. That's W-A-Y-F-A-I-R dot com.

• 19:05Josh Clark?

  So check this whole, I should say, misunderstanding of dopamine as the ultimate pleasure chemical. If you take a drag off a cigarette, if you snort a line of coke, if, if the person you love like touches your hand, if, if you get like an A from, from the teacher, like you're gonna get a hit of dopamine and that's what, that's what your reward is. That's, it's pretty old. It's an old idea. At least it dates back to the middle of the 20th century, which is, we're getting further and further away from, which makes me gulp. But the, the, that idea being discredited is pretty old too. Like it didn't last very long. The problem is its legacy stuck around for a really long time. It's still around today.

• 19:48Speaker 02

  Yeah, for sure. There was a researcher, speaking of old, named James Olds, in the 50s and 60s, who did some experiments with rats and said, hey, every time I give these rats a little electrical stimulation in just the right place, right there behind the ear, they're gonna keep pulling that lever down, or whatever act I'm making them do, that they'll just do that over and over and over and over and over, as long as I keep stimulating that area.

• 20:16Josh Clark?

  Right. So what they said was, okay, there's something going on with dopamine in, in this, this, I guess, pleasurable act that the, that the rat is doing to itself. And that got followed up in the-

• 20:29Speaker 02

  Whoa, whoa.

• 20:30Josh Clark?

  That got followed up in the 70s by a guy named Roy Wise, who depleted dopamine receptors in rats and found that they would not seek out food and they wouldn't seek out methamphetamines that, that were just there on the offer. Those rats could have as much meth as they wanted. And they were like, nah, I don't want any. And crucially, critically, Roy Wise and his colleagues misinterpreted that as a lack of experience of pleasure, not a lack of motivation. And it wasn't until the 80s that some other people came along and were like, no, we, we've been getting this wrong all this time.

• 21:06Speaker 02

  Yeah, in the 80s, they use sugar instead of methamphetamine, I guess. And once again, very kind of cruelly, they cut off, they, they-

• 21:17Speaker 02

  Didn't allow them any dopamine. They killed them off with drugs. But this time they gave them the sugar and they said, um, they're liking the sugar. You can tell by the look on that little guy's face that he enjoys it. But, and this is the key, it's not coming back and saying, give me more sugar, give me more sugar.

• 21:34Josh Clark?

  Right. Or give me more meth.

• 21:38Speaker 02

  Sure.

• 21:40Josh Clark?

  So this whole thing, this changed our understanding, at least in, in the like academia, among people who study this kind of thing. It, we realized we were misinterpreting what we were seeing. And that, um, a lack of dopamine didn't lead to a lack of pleasure called an ahedonia or anhedonia. It was a lack of motivation to seek out that pleasure. That's the effect of not having enough dopamine that we found from those rat tests. So like this whole new framework of understanding, it kind of came along. Because, to be clear, dopamine is very much associated with things that give us pleasure. And it does seem like the more pleasurable something is, the more dopamine gets released.

• 22:25Josh Clark?

  Like, for example, I think I saw like eating something that tastes really good. Increases your dopamine levels by a hundred percent sometimes.

• 22:33Speaker 02

  Yeah.

• 22:34Josh Clark?

  But cocaine increases your dopamine levels 10 times that.

• 22:38Speaker 02

  Yeah.

• 22:38Josh Clark?

  So the more intense the pleasurable experiences, the more dopamine gets released. So it's definitely associated with it. What they found is like, the dopamine is not making you feel pleasure. There's something else involved. It's just, it's never caught with the smoking gun, but it's always there when the dead body's found. And it has this mysterious smile on its face because it knows you can't prove anything.

• 23:01Speaker 02

  Yeah, it's, well, it's liking versus wanting. And that's a, a theory of reward behavior where liking is that, that pleasure. That, that hit you get, right? When you put that. Bite of peanut butter pie in your mouth is that pleasure. Wanting is the motivation to earn the reward that you get out of having that peanut butter pie.

• 23:23Josh Clark?

  Right.

• 23:23Speaker 02

  Um, like, you know, you're up in the hotel room. They, they don't have room service, but you can get up out of bed and you can get dressed and you can get down the stairs because the elevator is broken and get that peanut butter pie if you want to. Uh, but dopamine isn't enough to motivate you to get up and go get that peanut butter pie necessarily, even though you have great, great memories of the taste of it on your tongue and you love that stuff.

• 23:51Josh Clark?

  Right, but if you do get up and go get that peanut butter pie, that means that in the past you've had peanut butter pie or have created an image of the peanut butter pie you've never had. That's so great that the dopamine is, is produced in enough amounts to actually get you up out of bed, dressed and going down the stairs to get that peanut butter pie. They're related in that way.

• 24:14Speaker 02

  Yeah, absolutely. Um, so it's not actually causing the pleasure. It's just influencing how your brain is, uh, taking all this stuff in basically. And there are a couple of different ways of looking at how this happens. Um, there's one theory called a, uh, that it's prediction error. So you get, you get more bang for your buck, basically. Um, you, you expected to like that peanut butter pie, but this was the best peanut butter pie you've ever had, maybe the best dessert you've ever had in your life. And you're like, wow, that, your brain says that was way, way better than I thought it was going to be. So it reinforces it.

• 24:51Josh Clark?

  Right, and to put it in kind of computational terms, uh, dopamine is a prediction error. Somehow that chemical measures the difference between what you expected and the amazing reward you got. And the greater the difference, the more pronounced the connection that dopamine is going to make between going and getting peanut butter pie and eating peanut butter pie. So you'll have more motivation to do it next time.

• 25:16Speaker 02

  Yeah, uh, the other way of thinking about it is the, the dopamine itself is the motivational signal. So it's what makes me get out of that bed and put on my clothes and actually go down the stairs because I'm motivated to go get that, that, uh, reward.

• 25:34Josh Clark?

  Right, and this is where that awakenings anecdote comes in.

• 25:38Speaker 02

  Let's hear it.

• 25:39Josh Clark?

  So you were talking about how, you know, the peanut butter pie motivating you to get out of bed and actually go. That definitely jibes with research, particularly something reported by Oliver Sacks in the book, and then later the movie Awakenings. There was a, an epidemic of something called encephalitic lethargia, which is what happened to Robert De Niro's character. Remember as a boy, he caught this thing and then he just kind of froze in place. It's where you develop Parkinson's symptoms so much that you just don't, you can't move. You don't, you're, you're, you cannot move. You have, you don't have the required dopamine to actually move. So you're just sitting there frozen in place like a statue.

• 26:24Josh Clark?

  But anybody who saw this movie remembers being amazed by this scene. If a certain patient is stimulated, their dopamine is stimulated just enough, they can actually overcome that being frozen in place. And so there's a famous scene where Oliver Sacks tossed one of the patients some oranges and she caught them. Like she was a frozen statue and all of a sudden she's catching oranges and then juggles with them.

• 26:50Speaker 02

  Yeah.

• 26:51Josh Clark?

  Or there's another patient that was on the beach, I believe in their wheelchair, saw someone drowning and was motivated to get up and go save the person and then come back and, and go back to this frozen statue kind of stasis.

• 27:04Speaker 02

  Great scene.

• 27:06Josh Clark?

  It is. So like that, that has to do with the motivational aspect of dopamine and that given the right stimulus, even something that tremendous has just, just a crazy amount of Parkinson's symptoms can be over, overcome or overwhelmed by that dopamine hit.

• 27:26Speaker 02

  Yeah, absolutely. And then jumping back to that first one, the prediction error, they've done research on people who gamble, who play cards and play the slot machines and stuff. And they, their brains experience about the same amount of dopamine activity when they almost win. Like you got that big pot in the middle of the table, you're playing poker and you lose at the last second, your dopamine level will be about the same as if you had actually won it.

• 27:56Josh Clark?

  Yes.

• 27:57Speaker 02

  Which is pretty remarkable.

• 27:58Josh Clark?

  And then I think it kind of qualifies as a third interpretation. The, the most current study I've seen.

• 28:07Josh Clark?

  Seized dopamine is essentially the thing that allows us to learn. If you connect one thing to another, it's because dopamine had you make that connection. And then depending on what kind of effect those two things have on you, that connection might be very, very strong.

• 28:22Speaker 02

  Yeah.

• 28:22Josh Clark?

  So you're motivated to go seek it out again. But at base, what dopamine is doing is allowing us to form connections. Imagine the world if we didn't connect one thing to another. Like if I didn't connect turning on the computer and stepping up to the microphone and recording a podcast, like we wouldn't do anything. We would just be completely lost if we couldn't make connections. And it seems like dopamine is the basis of all that.

• 28:47Speaker 02

  Yeah, pretty cool.

• 28:49Josh Clark?

  Like, the whole world would suffer because we wouldn't be podcasting, Chuck.

• 28:54Speaker 02

  Well, that's debatable.

• 28:57Speaker 02

  You know, we're not poo-pooing the idea that addiction and dopamine are heavily tied with one another. We're just sort of trying to point out that there's a lot of other things at play when it comes to dopamine, and that sort of has unfairly maybe gotten all the press. But we do have to talk about it some more. We talked about it plenty of times, certainly in our addiction podcast episodes. But it does play a pretty big role in drug abuse and addiction. It does reinforce the, you know, the idea that you want to keep using those drugs because it's making you feel good. And when we're talking about, you know, you're talking about the woman juggling oranges

• 29:41Speaker 02

  in that movie and how remarkable that is.

• 29:44Josh Clark?

  Right.

• 29:44Speaker 02

  If they've given you Parkinson's drugs and they just flood your brain with dopamine, they found that 10% of the people that have had that treatment turn into gambling addicts. And I would imagine they're people who already gambled. I don't think it like drove them to start gambling. But that just goes to show you the power of like what a flood of dopamine will do to your brain. And it's a pretty, it's a pretty clunky way to deal with it, I think.

• 30:11Josh Clark?

  Yeah, I think that's what you were referring to earlier when you were saying like that understanding of volume transmission.

• 30:18Speaker 02

  Yeah.

• 30:18Josh Clark?

  Theory of dopamine release. That's what the drugs are based on, like that understanding and that misunderstanding. And like, yeah, that's what happens. It's like, yes, if it does crawl across the brain and runs into whatever neurons that it can trigger, it's going to have all sorts of other knock-on effects.

• 30:34Speaker 02

  Yeah, totally.

• 30:36Josh Clark?

  So I guess our current understanding of how dopamine relates to addiction is that it connects drugs with pleasure. And as I was saying before, the more intense the experience, especially the reward, you can have a negative experience. And I think they're starting to figure out dopamine has something to do with that, too. But as far as we know, the more intense the reward, the greater the flood of dopamine. And so the greater, the stronger the connection you make between, you know, pressing a lever and a scientist giving you a bunch of meth.

• 31:14Speaker 02

  Yeah, absolutely. But that is, to be clear, just part of the recipe of what leads to addiction. I don't, maybe there are people out there saying that, but I don't know if anyone really is saying like, it's all because of dopamine.

• 31:28Josh Clark?

  No.

• 31:29Speaker 02

  It is, it is part of the recipe in addition, obviously, to your genetics. Just the fact that drugs are out there and available and their environmental pressures and influences, all kinds of reasons that people start to take drugs or continue to take drugs. And as far as the continuation, dopamine is, is definitely a part of it.

• 31:53Josh Clark?

  Right. And so one of the ways that you learn to take drugs is not just from the fact that your, your brain is flooded with dopamine, which allows you to make that connection very strongly. But the brain actually changes in response to those increased floods of dopamine. Because it's not set up to release dopamine like that repeatedly over long periods of time. It can do it once in a while.

• 32:17Speaker 02

  Yeah.

• 32:17Josh Clark?

  But you, you, you can't really do it too often, because then the brain responds by shutting down dopamine receptors. The problem is, is that this means that you have to do more drugs to get that sensation, as far as you know. And that's what creates the cycle of addiction. That, to me, smells vaguely of being almost out of date.

• 32:43Speaker 02

  Yeah, I know what you're talking about.

• 32:46Josh Clark?

  But it does make sense, then, that the ideal drug would trigger a maximum release of feel-good chemicals, but a minimum release of dopamine. If anybody could ever come up with a drug like that, people would be able to do drugs all the time, they'd never get addicted.

• 33:02Speaker 02

  Sure, but they have other negative effects on the body.

• 33:06Josh Clark?

  Sure, sure. Can't forget about that.

• 33:08Speaker 02

  Yeah, yeah. The other bad thing, obviously, if you're gonna do the amount of drugs it takes to shut down your dopamine receptors, because your body's like, wait, wait, wait, this isn't right, let me shut this down, is it's not just shutting down the dopamine receptor that makes you wanna, you know, do more cocaine or whatever, it's just shutting your dopamine receptors down. So you mentioned it earlier, anhedonia, that's the idea that you don't receive pleasure from any activity. And if all of a sudden your dopamine has been shut down such, because you've been doing drugs, that you're not getting any kind of pleasant feel-good stimulation from life, then that could be another reason that you up your desire to do drugs.

• 33:53Josh Clark?

  Yeah, and then there's one other factor involved that with fewer dopamine receptor sites, remember you said that one of those dopaminergic pathways is related to executive function, like impulse control, responsibility, that kind of stuff?

• 34:09Speaker 02

  Yeah.

• 34:09Josh Clark?

  Well, with lower levels of dopamine, the theory goes that you are more likely to engage in reckless behavior to get drugs. You might do things that you normally wouldn't do, not because you're just this addict who has to have it, but partially also because you don't have the impulse control that you did before you became addicted to drugs and your dopamine receptors started shutting down.

• 34:35Speaker 02

  Yeah, and I think that's, I mean, we talked about it in the addiction app, that's, it's not just the effect that the drug has on your body, the negative effects that it physiologically has on your body, but the behaviors that you start engaging in when you're under the influence of drugs and want more drugs and maybe can't find the drugs, that's Maybe almost worse than the physiological ramifications, you know?

• 35:01Josh Clark?

  Oh, yeah, for sure. And it also ties in with risk-taking because dopamine is connected to risk-taking. And in fact, they found that some people seem to be biologically, physiologically predisposed to risk-taking based on their dopamine levels. Then in fact, they find that they have fewer what are called autoreceptors. Apparently, over time, we've evolved to create on dopamine neural cells, a site called an autoreceptor that actually catches some of the dopamine. It helps regulate it, like it never makes it out. So it keeps the amount of dopamine down to a regulated level. So the fewer autoreceptors you have, if you're still pumping out dopamine, you get a much greater impact from that dopamine.

• 35:46Josh Clark?

  And they have correlated that to risk-taking. People who have fewer dopaminergic autoreceptors take more risks, at least according to some studies.

• 35:56Speaker 02

  Yeah, and they've also done studies where they found that that risk should or needs to be tied to a reward, like a gain, basically. There was a study from the University of College in London in 2015 that said subjects whose dopamine levels was higher, it was boosted artificially with medication, would choose risky options more often if it involved a potential gain. They didn't see that same thing going on if there was a potential loss involved. So there's definitely a tie to a gain, or another way of saying that would be a reward.

• 36:33Josh Clark?

  Yes. And then also, that impulse control is also a huge hallmark of ADHD symptoms. And so ADHD is very commonly associated with some sort of dopamine deficiency. And from what I've seen, there isn't a, like, an across-the-board, we haven't discovered some across-the-board type of brain that's like, yep, if you have this brain, you have ADHD and vice versa. And we're not even certain exactly what effect the dopamine is having. We're almost just kind of like seeing effects.

• 37:11Josh Clark?

  That are the behavior of people with ADHD and saying, hey, that we know that dopamine does that, or if you don't have dopamine, you're more likely to do this. So there's this correlation. It's just not, it's never been like completely shown yet. I think it probably will be at some time, but we don't really know how ADHD is linked to dopamine. But there's, we're almost certain that dopamine drives at least some of the ADHD symptoms. It's just because of that, people have made leaps in understanding. Like there's a, there's a longstanding myth about people with ADHD that they do these impulsive behaviors to get a hit of dopamine. Well, that's based on that old idea that dopamine is a pleasure

• 37:55Josh Clark?

  producing chemical or reward producing chemical, where instead it might be that people do these behaviors that are impulsive because they don't have the dopamine that can regulate their impulses. And so they have less impulse control. We're just still sorting it out, I guess.

• 38:13Speaker 02

  Yeah. All right. Should we take our final break here?

• 38:17Josh Clark?

  Yeah.

• 38:18Speaker 02

  All right. We'll take a break and we'll talk about, oh, boy, it's going to be so much fun, social media, right after this.

• 38:39Josh Clark?

  Buy smart, drive for less and trade for more. That's Toyota affordability. And it all starts with a great deal on a truck from your local Toyota dealer.

• 38:49Speaker 02

  That's right. Make a smart buy on the off-road ready Tacoma or half ton Tundra, two of Toyota's most capable and longest lasting trucks, built with the strength for the tough jobs, the tech to power your next big adventure, and the rugged style for everything in between.

• 39:01Josh Clark?

  Or discover Toyota's off-road lineup, including the iconic forerunner and Land Cruiser, designed to go beyond the everyday. And with Toyota's proven reputation for quality and reliability, plus hybrid power on many models, you can get more for every mile and drive for less along the way.

• 39:17Speaker 02

  That's right. And long after you leave the lot, your Toyota keeps delivering with great resale value. So you could trade in for more when you're ready for your next Toyota. From a great deal today to a great value tomorrow, a Toyota is right for you. Shop toyota.com for deals and details, or stop by your local Toyota dealer today. Toyota, let's go places.

• 39:42Speaker 02

  Hey everybody, cozy season is upon us. And that means crisp mornings, that means soft layers, and that means Bombas.

• 39:49Josh Clark?

  Yeah, Bombas makes your comfiest fall staples, so you can make the most out of one of the best seasons of the year. Bombas has new suede moccasins that are perfect for fall because they have cushy soles, a sheerling lining, and they're made of water-resistant suede.

• 40:03Speaker 02

  That's right, and their slippers are everything you'd want for a cozy night in, made with the softest, squishiest materials.

• 40:08Josh Clark?

  And of course, Bombas has socks. Not just any socks, socks for every type of weather, every type of occasion, because fall can be fickle, and Bombas makes socks that can handle it all. And, the best part about Bombas, for every item you purchase, they donate an essential clothing item to someone facing housing insecurity. One purchased equals one donated, with over 200 million donations and counting.

• 40:30Speaker 02

  So head on over to bombas.com/sysk and use code SYSK at checkout for 20% off your first purchase. That's B-O-M-B-A-S dot com slash S-Y-S-K, using code SYSK at checkout.

• 40:49Josh Clark?

  Everyone has a story to tell. What's yours? The moment you met your partner, landed that promotion? For people living with a rare disease, life can feel divided into before the diagnosis and all the after moments that follow. On Voices of Vivgard, Vivgard is also known as its generic name, Efgartigimod Alpha F-Cab, you'll hear powerful stories from people facing challenges and embracing a life with a rare disease.

• 41:12Speaker 02

  Join host Andra Stratten as she guides listeners through honest conversations about life after diagnosis. You'll hear how each guest worked with her care team on their treatment plan, as well as their personal challenges, setbacks, progress, and moments of connection.

• 41:25Josh Clark?

  These stories reveal that life is bigger than a moment, a condition, or a tough day. Listen to Voices of Vivgard on the iHeartRadio app, Apple Podcasts, or wherever you get your podcasts.

• 41:50Speaker 02

  All right, so we're back and we promised talk of social media because I think everyone is pretty hip to the fact now that notifications and the dings and the likes and the loves and the hearts and all the things that come through various, interacting with various social media platforms.

• 42:09Josh Clark?

  You just sounded so old, dude.

• 42:11Speaker 02

  I know. That's great. In this case, I love being old. I don't want any of it.

• 42:15Josh Clark?

  I'm with you.

• 42:16Speaker 02

  But in any case, all of that stuff combines to give you a hit of dopamine and it's specific and you're like, fine, that's great, whatever. But it's specifically structured and built that way and coded that way so that you will become addicted to that social media platform. And they have admitted as such. In 2018, it was a big news item when they were, I don't know, it was like congressional testimony or something. Can't remember exactly, but there was a VP at Facebook who came out and was basically like, hey, this is something we did on purpose. And it was a core foundation was the really, the quote that kind of stuck

• 42:58Speaker 02

  out with how people behave using our platform. Like, it was a part of the core strategy to get people to come back again and again and again.

• 43:08Josh Clark?

  Yeah, and that strategy was based on, this was Chamath Palihapitiya, who was a VP of user development at Facebook. And they said that this was based on short-term dopamine-driven feedback loops. And, you know, this is all old news to us now. I mean, this was six years ago. Think about how much our understanding of what social media does to us. But in 2018, that was a groundbreaking admission. But it's true. And I mean, that's essentially how social media works. Like, you get the app and you start to realize that if that little like badge number comes up and says, hey, you have like two notifications, you go into it, you're going to get some sort of reward of some sort. You're going to,

• 43:52Josh Clark?

  like you said, get a ding or a like or a heart or something like that. And that is a reward to you. And so, based on the mesolimbic theory of dopamine.

• 44:05Josh Clark?

  We get a dopamine hit and so we learn to come back. And apparently also randomness has a lot to do with it. Because as we start to be able to predict when we'll get a reward, that dopamine stops being a part of that whole experience. So if it can be done randomly, we don't know when we're going to get a reward. It has a maximum effect of releasing dopamine and thus teaching us to go back to social media over and over and over again.

• 44:34Speaker 02

  Yeah, totally. There's also this psychiatrist named Dr. Cameron, S E P A H, I guess, Sepa?

• 44:43Speaker 02

  Is that how you'd say it then?

• 44:44Josh Clark?

  Sepa or Sipa?

• 44:46Speaker 02

  Okay, one of those three. Who came out and said, all right,

• 44:53Speaker 02

  there's this term that I'm going to float out there and it's called a dopamine fast. And the idea when that was floated was people heard that and they said, oh, well, dopamine just means, it's just a catch all term, basically, for any sort of addictive behavior, like reinforcement. And you can go on a dopamine fast and like, you know, put that social media app down for a couple of weeks. And when you come back, it's just going to, like, your brain's going to have a little rest from that thing and you're going to feel amazing about how much you love it when you come back. And that's not at all what Dr. Cameron was talking about or meant.

• 45:36Josh Clark?

  No, huh? Dr. Sipa, Sepa was basically saying like,

• 45:43Josh Clark?

  like, he really misused dopamine fast. And he even said to the New York Times, like, I didn't mean it like that. Don't take it like that. I don't mean it literally. And everybody said, too late, we're going to take it literally. And so there was this movement, I think people still do it, of self-denial of everything from, like, people stopped interacting with other people. People stopped eating foods they found pleasurable. They stopped talking if they didn't need to. Anything that could conceivably give you a release of dopamine.

• 46:16Josh Clark?

  And their premise was that if they did that, it would be like going and drying out on heroin or cocaine, so that when you come back, that that first experience again with heroin or cocaine is that much more amazing because you've kind of replenished your endocannabinoids and opioids and all that stuff. Dopamine does not work like that. If you stop flooding your brain with dopamine, it doesn't replenish, it doesn't need to replenish. That's not how it works. But that's what people were doing. They just completely misinterpreted it. And it was based on faulty science and Dr. Seppa essentially using the wrong term.

• 46:54Speaker 02

  Yeah, I think the idea that he was talking about was, hey, put that stuff down and go do other things that you find pleasure in.

• 47:05Josh Clark?

  Right.

• 47:06Speaker 02

  Live in the world or go out in nature or, you know, kind of get a hold of your life again, so you don't feel like you're, you know, tied to this social media app for your happiness.

• 47:18Josh Clark?

  Yeah. Our moms used to call it going to play outside for a while.

• 47:22Speaker 02

  Right.

• 47:23Josh Clark?

  Or summer, I think is another term it used to be called.

• 47:26Speaker 02

  Yeah.

• 47:27Josh Clark?

  But instead, this guy called it a dopamine fast and people really took a left turn with it. So he identified six compulsive behaviors or categories that he was saying, you could really, you could really do good for yourself by taking a dopamine fast or a break from emotional eating, excessive internet usage and gaming, gambling and shopping, porn and masturbation, thrill and novelty seeking, which I took to mean taking a break from thrill kill murder sprees.

• 47:58Speaker 02

  Right.

• 47:59Josh Clark?

  And recreational drugs.

• 48:00Speaker 02

  Yeah.

• 48:01Josh Clark?

  But he also said, you know, anything that you feel like has got a hold on your life, if you just stop and step away from it, it will have less a hold of your life. So TV would definitely be in there probably for a lot of people.

• 48:13Speaker 02

  Yeah.

• 48:14Josh Clark?

  But if you step back and look at what this guy's talking about, it's the most basic thing that people have been doing for eons. And yet, just by slapping. Dopamine fast on it, it became sticky and buzzy and brainstormy or Java stormy and like super corporate and people just really got into it and started thinking like, you know, if I, if I fast from dopamine, when I come back, I'm going to have so much dopamine that I'm going to be the most motivated, focused, greatest UX PM of all time.

• 48:49Speaker 02

  Yeah. Thanks a lot.

• 48:51Josh Clark?

  And that's just not how it works, unfortunately.

• 48:53Speaker 02

  No.

• 48:54Josh Clark?

  Yeah, I guess it's a weird way to end this whole thing, but that's how it ends, huh?

• 48:58Speaker 02

  Yeah. I mean, that's our current understanding.

• 49:01Josh Clark?

  Yeah. I feel like this is one we would be able to do five years from now, just to kind of revisit. What do you think?

• 49:08Speaker 02

  Nah.

• 49:09Josh Clark?

  Okay.

• 49:10Speaker 02

  I mean, we've never done that.

• 49:12Josh Clark?

  That's dopamine as we understand it in 2024, everybody.

• 49:16Speaker 02

  That's right.

• 49:17Josh Clark?

  If you want to know more about dopamine, go out and read about it, but be very specific and selective of who you go read. There are some popular people who know what they're talking about out there, but there's plenty that don't. So I guess if you run across somebody who refers to dopamine as a pleasure chemical or something like that, just turn around and walk away and go find somebody else. How about that, Chuck?

• 49:37Speaker 02

  That sounds good.

• 49:38Josh Clark?

  Chuck said that sounds good, everybody. And that means it's time for listener mail.

• 49:43Speaker 02

  I'm going to call this from a conductor. We heard from quite a few conductors so far. And that's just on day one after release. So it's pretty great to know that there are people out there that know about this stuff better than we do.

• 49:56Josh Clark?

  That's amazing.

• 49:57Speaker 02

  Hey, guys. Thank you so much for the episode about conductors. I squealed with joy when I saw it in my feed as I started my hour long commute. I teach high school orchestra and I'm an orchestral, orchestral, excuse me, musician with former aspirations of becoming a professional conductor. So it's fun to hear an outsider's perspective. You're wondering what exactly is on each musician's stand during a performance. I love Chuck's analogy of it being like an actor's script with only their lines. And that's pretty close. But sometimes there are small annotations of what to listen for from other sections of the orchestra, particularly after a long section of inactive playing or rests to help figure out what you, where you are in the music. That's the part, remember,

• 50:39Speaker 02

  I just couldn't believe there'd be like nothing to cue you. And I saw other stuff where there were sometimes numeric notations and other conductors said there were long bars and things that you would pay attention to. Back to the email, though. This is another key job of the conductor, which you didn't touch on as much. As they have the entire score, they often give entrance cues to specific instrumentalists or sections. Additionally, there are usually rehearsal markers that delineate the beginnings of phrases or larger sections. This not only makes rehearsing easier, but also gives greater structure and scaffolding to the player. It's similar to punctuation or paragraph structure in a novel.

• 51:19Speaker 02

  Experienced musicians can often almost more or less feel their entrances based on their contextual knowledge of the piece and the music phrasing.

• 51:28Josh Clark?

  You need it.

• 51:28Speaker 02

  There's an old adage, "You spend your time practicing at home to learn your part. Rehearsal time is spent learning everyone else's."

• 51:36Josh Clark?

  Oh, that's cool.

• 51:37Speaker 02

  It's pretty good. The conductor is the facilitator of this process. You hit the nail on the head, guys. The interpreter of the score. That is from Brittany.

• 51:46Josh Clark?

  Me and Chuck, we did it.

• 51:49Speaker 02

  Yeah, we got, I think, four or five conductors all wrote in and said, like, "We did a pretty darn good job on it." So that feels great.

• 51:56Josh Clark?

  Tell me they said bravo.

• 51:58Speaker 02

  Hmm, I didn't see a bravo.

• 51:59Josh Clark?

  Nah.

• 52:00Speaker 02

  Sorry.

• 52:00Josh Clark?

  Maybe we'll get one someday.

• 52:02Speaker 02

  Yeah.

• 52:02Josh Clark?

  That's pretty good. Who is that from? Brittany?

• 52:04Speaker 02

  Yeah, Brittany.

• 52:05Josh Clark?

  Thanks a lot, Brittany. We appreciate that. And to all the conductors who wrote in, thank you to you all. And if you want to be like all the conductors who wrote in, like Brittany, you can send us an email, too. Send it off to [email protected].

• 52:23Speaker 00

  Stuff You Should Know is a production of iHeartRadio. For more podcasts, iHeartRadio, visit the iHeartRadio app, Apple Podcasts, or wherever you listen to your favorite shows.

• 52:39Josh Clark?

  Buy smart, drive for less, and trade for more. That's Toyota Ford ability. And it starts with a great deal on an off-road-ready Tacoma or half-ton Tundra, two of Toyota's longest-lasting trucks, combining power for work, tech for adventure, and style in between. And they're built on a reputation for quality and reliability, which is why Toyota trucks are known for holding their value, which could mean big savings when it's time for your next Toyota, so get a great deal today and a great value tomorrow. Shop toyota.com for more. Toyota, let's go places. Introducing Voices of Vivgard. Vivgard is also known as its generic name, Efgart Tigamod Alpha F Cab. And this new show features firsthand stories from people living with a rare disease.

• 53:20Josh Clark?

  Hosted by Andrew Stratton, these perspectives highlight that life is more than a moment, a condition, or a tough day. Living with a rare disease can be challenging, but it does not define the Voices of Vivgard. In these episodes, they share their stories, from diagnosis to working with their care team on their treatment plan. Listen to Voices of Vivgard on the iHeart Radio app, Apple Podcasts, or wherever you get your podcasts. Hey, everybody. I am here to talk to you about Dude Wipes, who offer fragrance-free wipes that are made with 99% water and plant-based ingredients. So they're gentle enough for sensitive skin, but they're tough enough for even the worst messes. Water cleans better, and Dude Wipes flushable wipes deliver textbook freshness and ultimate clean.

• 54:01Josh Clark?

  And just like human body molecules, Dude Wipes are made with 99% water, plus they're plastic-free. Dude Wipes give the best clean pants down. Dude Wipes, available at major retailers nationwide.

• 54:13Speaker 05

  This is an iHeart Podcast. Guaranteed Human.