Our brains are full of fun facts: the memory span of a goldfish, Marie Antoinette’s famous words, the vomitoriums of Rome, and more. But what if it’s all wrong? In this episode, I debunk more than a dozen common misconceptions and then ask: Why do we remember misinformation so easily? And is there a better way to learn?
Special thanks to our guests:
Culum Brown, Head of the Fish Lab at Macquarie University
David Rapp, Psychology Professor at Northwestern University
Margaret Rodenberg, Author of “Finding Napoleon”
Andrew Rabin, Professor of English at the University of Louisville
Caillan Davenport, Associate Professor of Classics at the Australian National University
Jason Feifer: This is Build For Tomorrow, a podcast about the smartest solutions to our most misunderstood problems. I'm Jason Feifer, and in each episode, I take something that seems concerning or confusing today and figure out where it came from, what important things we're missing, and how we can create more opportunity tomorrow?
Jason Feifer: Have you ever had this experience? You're in a conversation with someone and you say something you are totally sure is true. Maybe it's some interesting fact like... I don't know, you say that a goldfish only has a two second memory, and maybe the person you're talking to says, "Really?" And you say, "Really," but then you think, "Wait a second, do I actually know that that's true?" Then you start asking yourself some questions. "Do I actually know that or do I just think I know that? Where do I even hear that? Did someone say it? Did I read it? And where?" And you realize maybe this thing that you just said is true is actually false.
Jason Feifer: I will be honest, this happens to me a lot. Sometimes I'll backtrack and admit that I'm not really sure about the thing I just so confidently said, and maybe I'll even whip out my phone and do a little research, but mostly I just carry on. I think, eh, doesn't really matter if it's true and yet, what if it does matter? I'm going to make the case right now that it matters, and here it goes.
Jason Feifer: Recently, a writer I work with sent me a link to this fascinating Wikipedia page. Dare I say, it might be the very best Wikipedia page. It is called List Of Common Misconceptions, and it's just an insanely long list of, I don't know, hundreds of these things, things that people just commonly believe, but that are in fact not true. It's broken into categories, food, film, television, history, biology, language, and so on. And one of these hundreds of misconceptions goes like this, "The memory span of a goldfish is much longer than just a few seconds."
Jason Feifer: When I read that line, I literally gasp because I can't even remember when I heard this fact, but it always seemed so true, so true that everyone else seems to think it's true. So true that it just shows up casually in pop culture, like in this scene from Ted Lasso.
Audio Clip (Ted Lasso): You know what the happiest animal on earth is? It's a goldfish. You know why?
Audio Clip (Ted Lasso): No.
Audio Clip (Ted Lasso): Got a ten second memory. Be a goldfish, Sam.
Jason Feifer: I'd heard two seconds. Ted is saying 10, but whatever, same thing. I owned a lot of goldfish as a kid. It doesn't seem fair to keep an animal in a tiny little bowl, but I was always comforted by this fact. If a goldfish only has a memory of a few seconds, then who cares where it lives? It can't remember where it is anyway, but wait a second. Now that's not true?
Culum Brown: Well, the whole idea that a fish might have a two second memory is bordering on ridiculous.
Jason Feifer: You want someone who actually knows the memory span of a goldfish? Well, you call this guy.
Culum Brown: My name is Professor Culum Brown, and I'm head of the fish lab here at Macquarie University. And I guess I mostly work on behavior and ecology and evolution of fishes, but particularly cognition. So it's all about how smart fish are.
Jason Feifer: And Culum says, look, he gets it. People have a low expectation of fish intelligence. When he was a kid, he heard the same thing.
Culum Brown: Gosh, even when I was a child, we heard this phrase, fish have a two second memory. And look, as a researcher, I've traveled the world and worked in many countries and spoken to lots and lots of different people. And wherever you go, the myth is much the same.
Jason Feifer: Not only is the myth not true, but if you know anything about biology, it doesn't even make sense. If you're an animal and you cannot retain information for longer than a few seconds, then you're going to die. You'll forget where the food is or where the predators are, or how to get in and out of places.
Jason Feifer: So, okay. Now you're wondering, as I did, if a goldfish memory is longer than two seconds, how long is it? Culum has done some work on this very subject?
Culum Brown: I'll give you a good example from some of the research that I did, using an Australian freshwater fish, which is much the same as a goldfish.
Jason Feifer: He built a net the length of an aquarium and cut a hole in a particular section, that he trapped these little fish in a part of the tank and basically watched as they figured out how to escape through the hole.
Culum Brown: And those fish solved that in about five trials, which was exciting. So a very rapid example of learning, and they obviously have to remember from trial to trial, right? And they're about 15 minutes apart, but what is even more interesting is we set those fish aside and tested them a year later, and they carried on as if it was yesterday.
Jason Feifer: What then is the memory span of a goldfish? Perhaps it's just as long as your memory. So, okay, aside from discovering that the Ted Lasso script writing team needs a fact checker and now feeling very bad about all the goldfish I kept as a child, what is the point of this exercise? It is this.
David Rapp: There's this really well known finding in psychological literature that shows if people feel like they can easily remember something, they believe that it's more likely to be true than if it's hard to remember something.
Jason Feifer: This is David Rapp, a professor in psychology and in the School of Education and Social Policy at Northwestern University.
David Rapp: And I study people's interactions with and processing of inaccurate information.
Jason Feifer: In fact, he runs a whole lab dedicated to this subject. This guy knows his stuff and his inaccurate stuff. And like he says, we have an information problem that is baked into our brains.
David Rapp: So one of the challenges is, we call them phenomenological feelings, our gut feeling about whether something is true is informed by ease of retrieval, the ease with which we can get something out of memory, but sometimes we can get things out of memory for reasons that are unrelated to whether they're true.
Jason Feifer: True. Like for example...
David Rapp: If someone repeats something over and over and over again, that's easy for me to retrieve, but just because something was repeated doesn't mean it was actually true.
Jason Feifer: Maybe that's so important, it's worth repeating.
David Rapp: If someone repeats something over and over and over again, that's easy for me to retrieve, but just because something was repeated doesn't mean it was actually true.
Jason Feifer: So what do you think? If you repeat the truth about repetitive untruths, does your brain reprogram itself or does it just break?
David Rapp: If someone repeats something over and over and...
Jason Feifer: Okay. I promise, I'm done with that, but here's the point. There is a wide gap between something that feels true and something that is true, and we often don't know the difference. Misinformation is of course, a giant subject these days and I don't want to bore you with a lecture about politics and the danger of online echo chambers and whatever else. So instead, let's explore this subject in a more enjoyable way.
Jason Feifer: Here's what we're going to do. I have gone through the Wikipedia page of List of Common Misconceptions and found a bunch that really surprised me, and that I think will surprise you. Stuff that just completely challenges things I thought were true because like David Rapp says, it just felt true and I'd heard it enough times, and it was easy to remember.
Jason Feifer: And so my team and I, we have done the research. We have talked to the experts and we have found the actual truth. I'm going to run through these things and I'm going to blow your mind. I'm going to make you feel like crap. Maybe your head is full of more misinformation than you thought. And then at the end, we will come back to David to get some advice on how to filter information better.
Jason Feifer: So coming up, I am about to destroy things you thought you knew about history, about food, about animals, about the Roman vomitorium. Oh yeah. You thought Romans vomited in the vomitorium? Just wait until you find out what the vomitorium actually was. It's all coming up after the break.
Jason Feifer: All right. We're back. So we're going to take a journey into things we thought we knew, but that we didn't actually know at all. We kicked off the episode by destroying one fun animal fact. So let's do another. We'll start with this snippet from personal finance personality and radio show host, Dave Ramsey.
Audio Clip (Dave Ramsey): Or possibly he is a financial planning lemming. You know what a lemming is?
Audio Clip (Dave Ramsey): That's an old school word.
Audio Clip (Dave Ramsey): These are small rats that run in herds and follow each other over cliffs.
Jason Feifer: That is a good summary of a lemming, at least as popular culture knows it. I'm sure you've heard this story many times. And why would this tiny animal commit mass suicide? That's not exactly a good strategy for long-term species survival. So the idea is this, the lemming is such a follower, such a mindless follower, that it just follows the lemming that's ahead of it, and that lemming follows the one ahead of it, and on and on. These mindless little creatures, following each other to their doom, instead of thinking for themselves.
Jason Feifer: It is a tidy metaphor, which is maybe why this story has always felt so true and has been so memorable, but lemmings do not hurl themselves off of cliffs. They do not commit any kind of mass suicide. They're perfectly fine. They're like normal animals. So where did this myth come from?
Audio Clip (Lemmings): Ahead lies the Arctic shore and beyond, the sea. And still, the little animal surge forward.
Jason Feifer: This is an influential 1958 Academy Award winning documentary from Disney called White Wilderness, which introduced the lemming to popular consciousness. It shows a swarm of lemmings approaching a cliff. They look like... I don't know. They look like hamsters, little rodents and below, there's an ocean of freezing deadly water.
Jason Feifer: The little lemmings surge forward, as the narrator says, and they tumble down these rocky cliffs until they reach the edge of the cliff.
Audio Clip (Lemmings): This is the last chance to turn back.
Jason Feifer: They look and move away. Another one comes over, looks, moves away. And then...
Audio Clip (Lemmings): Yet, over they go, casting themselves bodily out into space.
Jason Feifer: It is a wild scene. These animals are hurling themselves off like they've just been launched off a catapult. They land in the water one after the other, as if a ton of lemmings were just dumped off a truck. And wouldn't you know it, that is more or less what actually happened. In 1983, an investigation by the Canadian Broadcasting Corporation found that Disney flat out faked this whole thing.
Jason Feifer: First of all, the documentary was filmed in Alberta, Canada, where lemmings do not live. So these lemmings were collected elsewhere in Canada, trucked in, and then basically shoved down the cliff and into, well, what was actually a river, not the ocean. The documentary faked that part too, but for decades, thanks to Walt Disney, this documentary was the unquestioned authority on lemmings, and a cultural narrative grew from it. One that is so sticky, it's repeated everywhere, but don't worry. The lemmings are just fine, though maybe they're worried about us. After all, we are the ones who blindly followed each other into believing this story.
Jason Feifer: So what else don't we know about animals? I've got three more fun fact checks for you. Number one, piranhas. If you know anything about piranhas, it's that they're fish with scary, huge teeth. And if a human being is swimming in piranha-filled waters, well, the fish will swarm, attack and eat you down to the bone. We know this because, well, it goes back to president Theodore Roosevelt, who went on a hunting expedition in the Amazon rainforest in 1913, and then wrote a book about it, called Through the Brazilian Wilderness in 1914.
Jason Feifer: In the book, he described an insane swarming attack by piranhas. This then may have inspired the 1978 movie that has captured the imagination about piranhas. It was called piranhas.
Audio Clip (Piranhas): Well. They're shifting in here.
Audio Clip (Piranhas): David.
Jason Feifer: But in actuality, piranhas aren't that bad. Yes, they have big teeth because they eat a lot of other fish, but they also eat plants. And like most fish, they don't want to tangle with a human. Sure, they will bite you if threatened or if you encroach upon their spawning area, but even then, they typically only bite once and they get the hell away, and they don't swarm. You know what Teddy Roosevelt actually saw in 1913? He saw some local fishermen block off a part of the river, starve the piranhas for days, and then they pushed a cow into the river.
Jason Feifer: At that point, the fish were so hungry and crazed that yes, they did swarm the cow and turned it into a skeleton, but that is not what will actually happen if you get into normal waters with normal piranhas. Okay. Animal fact number two, if you cut an earthworm in half, it does not become two worms. Yes, there are some worms that will regenerate in all their parts, but not earthworms. Earthworms have a head, an area with vital organs, and a tail. If you cut through the vital organs, or if you separate the head from the organs, you just kill the thing. Don't do that. And number three, this one's going to help you sleep better tonight, no, people do not actually swallow an average of seven spiders in their sleep every year.
Jason Feifer: You know the average number? Zero, because first of all, people don't generally sleep with their mouths wide open, and if they do, they're snoring and spiders don't like vibration. Also, the spiders found in most American homes don't want to be anywhere near your bed because they'd rather be in the web where all the bugs are, and hopefully your bed is not full of bugs.
Jason Feifer: Okay. So that covers animals. How are you feeling? Like maybe everything you know is wrong? Well, just get ready for what's next because it's time to move on the people category. Quick, tell me the first thing you think of when I say the name Napoleon? Maybe you think French, good. That's true. Maybe you think French Revolution, also works, and maybe you think short, which is for good reason.
Audio Clip (Napoleonic Complex): Some people have said it's a Napoleonic complex.
Audio Clip (Napoleonic Complex): Oh, dear.
Audio Clip (Napoleonic Complex): I remember the first time I met him, we shook hands and he was... he seriously was like...
Jason Feifer: That's Joe Scarborough insulting John Stewart's height, back when those guys were publicly feuding. You know the phrase, Napoleonic complex, someone who's short and tries to overcompensate with bluster because that's what short, short Napoleon did. But here's the thing...
Margaret Rodenberg: We say he's this short Frenchman with a big hat, with his hand in his vest, and that he became overly ambitious because of his height, and most of that isn't true.
Jason Feifer: And this is someone who would know.
Margaret Rodenberg: So I'm Margaret Rodenburg, and I'm the author of "Finding Napoleon".
Jason Feifer: Which is a novel featuring Napoleon, but she's also the Secretary of the Napoleonic Historical Society, and in the interests of full disclosure...
Margaret Rodenberg: I'm five foot one, so we better get that out in the public as to why I even care about that.
Jason Feifer: And I, just for the record, am 5'7". So, okay. Here is the evidence that Napoleon was short. His recorded height was five foot two. He was tiny compared to all the people around him and his nickname was "The Little Corporal." Funny enough, all those things are actually true, but for surprising reasons that we'll get to in a bit, they don't actually mean that he was short.
Jason Feifer: So let's start with the most important fact, how tall was Napoleon?
Margaret Rodenberg: He was five foot six, which was average height for a Frenchman of his time.
Jason Feifer: [foreign language 00:14:29], not tall, but not so short, totally normal. The average American man today is just a little taller at five foot nine, and American founding father James Madison, who was President when Napoleon was in power was only 5'4". But of course, we don't go around talking about Madisonian complexes. So why did Napoleon become known as short?
Jason Feifer: There are a lot of reasons for this. British propaganda during his lifetime portrayed him as short, especially next to the big and hulking John Bull, which is a national character, kind of like America's uncle Sam. And yes, like I said, the French called Napoleon The Little Corporal. True, but here's the thing...
Margaret Rodenberg: It was a French endearment.
Jason Feifer: Napoleon was once a Colonel who was doing a Corporal's job, so Little Corporal, it was a compliment. And also, you know how people always say Napoleon was five foot two? Well, that is because...
Margaret Rodenberg: His autopsy was performed by people within his entourage, by a doctor who had been sent there. And he wrote in there that Napoleon was five foot two. But in fact, that was five foot two in French inches and French feet, which were larger than the English measurement.
Jason Feifer: Because there was no universal system of measurement back then, and from his death onward, history really piled on. A few decades after Napoleon died, he showed up as a character in War and Peace, and Leo Tolstoy writes about him as this small guy with little white hands, because Tolstoy was once a soldier and no fan of the French. Then in the early 20th century, an associate of Sigmund Freud's named Alfred Adler writes about inferiority complexes and associates them with people who have various physical attributes.
Jason Feifer: And somehow all this gets tied together and we get the Napoleonic complex, which makes you wonder, did Napoleon himself have what we would now call a Napoleonic complex? Margaret says probably not, and here we reach the final true, but misunderstood fact about Napoleon. Like I said earlier, he was always portrayed as shorter than the guys around him, which was true. You know why? Because he had an elite guard who was selected in part because they were all six feet taller up.
Margaret Rodenberg: So here is a short man who, if he cared about his height and his appearance, he would not surround himself all the time with people who were a foot taller than he was.
Jason Feifer: So there you are. Napoleon, not actually so short, just kind of normal. And you want a few other people whose central fact about them you probably have wrong? I've got four. Number one, Buddha wasn't fat. When Westerners think of Buddha, they probably think of the chubby guy in statues that you find in Chinese restaurants, but that's not Buddha. That's a 10th century Chinese monk named Budai, who is often called the laughing Buddha, but who's definitely not the same person as Siddhartha Gautama, the founder of Buddhism, who was born somewhere around 500 BC, and is always portrayed as thin.
Jason Feifer: Number two, Marie Antoinette did not say the one thing you think Marie Antoinette said. So let's set the stage. It is the lead up to the French Revolution.
Audio Clip (Marie Antoinette): And when they went to the Queen, her subjects had no bread. Do you know what she said?
Audio Clip (Marie Antoinette): Let the meat cake.
Jason Feifer: That's from the 2006 Kirsten Dunst movie which was called Marie Antoinette, and in the movie, right after that moment, they cut to Marie in a room with her girlfriends where she says...
Audio Clip (Marie Antoinette): That's such nonsense. I would never say that.
Jason Feifer: And indeed, she never said that. The phrase, "Let them eat cake," has been attributed to multiple Royal women over the years. Before Marie Antoinette, it was the holy Roman Empress Marie Therese, but during the start of the French Revolution, Marie Antoinette was especially hated because she was female and foreign, and pamphlets started attacking her as crazy, drunk, overindulgent, cruel, unfaithful to the king. And eventually, that she said, [foreign language 00:18:19], "Let them eat cake," though actually, the original French phrase was "Let them eat brioche."
Jason Feifer: So who actually said this line? Possibly nobody. Versions of this story have been found in other cultures for centuries, dating as far back as seventh century China, and it's always basically the same. A leader hears that their people don't have some basic food staple and they say, "Huh, why don't they just eat something else?"
Jason Feifer: And finally, one more person you might misunderstand. Isaac Newton did not come up with the theory of gravity after an apple fell on his head. We probably could have assumed that. It's a tale that's so tidy. It sounds like Isaac Newton made it up himself but in fact, Isaac Newton never claimed to be hit on the head with an apple. Instead, he only said that he saw an apple fall from a tree and that it got him wondering about why things fall downward.
Jason Feifer: So where did this story come from? Well, Newton died in 1727 and nothing much was made of his apple story until nearly 70 years later in 1791, when a different Isaac decided to spice things up. His name was Isaac D'Israeli. He was a British historian and his son Benjamin would go on to become Prime Minister, and this Isaac's most famous book was called Curiosities of Literature."
Jason Feifer: It's basically a collection of fun facts, including this about Isaac Newton, "As he was reading under an apple tree, one of the fruit fell and struck him a smart blow on the head. When he observed the smallness of the apple, he was surprised at the force of the stroke." And from that, apparently a myth was born.
Jason Feifer: Now let's move on. Here's a fun question. You know the phrase, "Ye olde?" As in, when you're in a small town that's trying to be quaint, it has a place called ye olde store or when you're playing this old Disney video game.
Audio Clip (Old Disney video game): Hello. Hello, welcome to ye olde magic shop, my friend.
Jason Feifer: Or in this bit from The Simpsons.
Audio Clip (The Simpsons): My knees are open only to the pleas of those who speak ye olde English.
Jason Feifer: Well, you ever wonder what the word ye actually is? Is it just the way people said, "The," a thousand years ago? The answer is no. It's actually a very old, very complicated sort of typo. We'll get into that, plus how we can better filter for real information after the break.
Jason Feifer: All right. We're back. So just a moment ago, I asked you to consider the word ye. As it turns out, the word ye did actually exist in the ancient world, but just not in the way that we see it used today. For this one, I called up Andrew Rabin, a regular guest here on Build For Tomorrow. He's a Professor of English at the University of Louisville, who specializes in the law in literature of early medieval England.
Andrew Rabin: It's the nominative plural of you. Ye gods, that's actually a great example of the ye, right? You gods.
Jason Feifer: So ye would be what? Ye would be all of you, is that the word?
Andrew Rabin: Yeah, actually, that'd be a good way of translating, "Y'all," for those of us in the south.
Jason Feifer: But the English speakers of the mid-fifth century also had the word Vee, which today we would of course spell T-H-E, but back then, instead of using T-H to make, they had a specific letter to make that sound. It was called thorn.
Andrew Rabin: Which looks a little bit like a modern day P. The problem with that though, is that there are two other letters that look almost exactly the same. The other one being P obviously, and then an old English letter win, which makes the W sound.
Jason Feifer: Because just to make clear here, as languages evolve, so do the letters that they use. So there were all sorts of letters from old and middle English that do not survive today. Okay. Back then, there were three letters and they looked really similar, but they made totally different sounds, and that wasn't actually a problem because the letters didn't confuse the highly educated monks who read and wrote manuscripts, and most everyone else could not read or write, but then...
Andrew Rabin: Jump forward several hundred years, with the invention of the printing press and the gradual development of more widespread literacy, the similarities of those particular letter forms becomes a hindrance.
Jason Feifer: Imagine, you work in a printing press and your job is to carve little letters onto tiny blocks that'll be used to print words. These three already similar letters, which are now shrunk down and carved by hand, start to look impossibly similar. People are getting really confused, and of course, there are more people reading now.
Jason Feifer: And as a result, the alphabet starts to change to accommodate all this. Between around 1450 and 1550, they basically just stop using the letter that makes the W sound, and then they create a brand new look for the thorn, which is that letter that makes the T-H sound. And here's what the new thorn looks like. Okay. Imagine a lowercase G.
Andrew Rabin: If you shave the top of its head off.
Jason Feifer: Got that? Can you picture it? Lowercase G, which has a little circle on top and then a little loopy guy underneath. Now take the top half of the circle and just lop it off. And yeah, now we've solved a problem because it does not look like a P anymore, which was the original confusion.
Andrew Rabin: But of course, it gets confused with the Y.
Jason Feifer: Because they did have the letter Y back then. So, okay. Let's picture this here. I know, there's a lot of letters, it's kind of confusing. The word we're talking about is the. Today, T-H-E. Back then, spelled thorn-e, but now the thorn looks like a lowercase Y.
Andrew Rabin: So even though you're looking at something that says V, your immediate response, the first thing you're going to think when you see that sign is going to be ye.
Jason Feifer: Which wasn't actually that confusing to people of the middle ages. This was just every day for them. They got it. They understood. It's sort of the way that we don't have problems every single day differentiating between a capital I and a lowercase L, even though they're functionally exactly the same when you type them, but as time went on, and particularly as more modern people looked back at old writing, these very similar letters started to blend together.
Jason Feifer: And soon enough, people are opening up yield stores, even though nobody from the time in which yield store is supposed to hearken back to would've ever actually said yield store. But this got me wondering, does our modern English clear up some of this confusion? After all, we now have fewer letters that are visually distinct, which means it's a lot harder to mistake letters today.
Jason Feifer: Andrew said, "Actually, it's quite the other way around because older versions of English had more specific letters."
Andrew Rabin: Phonetically, it was much less confusing. One of the big differences between middle English and modern English, they didn't have silent letters.
Jason Feifer: No silent G's or K's for example, the way we have now, but today, because we have fewer letters, they have to pull double duty, which for anyone learning the language is its own sort of confusion. That's why English is so hard, well, among many other reasons.
Jason Feifer: Okay. I've got even more ye old misconceptions from history for you. Here's a fun one. Vikings did not actually wear horns. If you're going to go invade from a boat, horns on your head are not practical. So where did that idea come from? Well, in the 1800s, archeologists did discover horned helmets in Scandinavia, but they dated from the bronze age and were used only by shaman. Those helmets however, probably inspired the costume designers for Richard Wagner's ring cycle operas, which included characters from Norse mythology, and that may have created the cultural image of Vikings with horns.
Jason Feifer: And speaking of misunderstandings and works of art, you know the story about Orson Welles' War of The Worlds? Quick recap, though I'm sure you're familiar with the basics of it. In 1938, he directed and narrated a radio drama about an invading alien army, which started like this.
Audio Clip (Orsen Wells War of the Worlds): Ladies and gentlemen, I have a grave announcement to make.
Jason Feifer: The whole thing then played like a news report.
Audio Clip (Orsen Wells War of the Worlds): Incredible as it may seem, both the observations of science and the evidence of our eyes lead to the inescapable assumption that those strange beings who landed in the Jersey farmlands tonight are the vanguard of an invading army from the planet, Mars.
Jason Feifer: As the story goes, this triggered mass chaos, absolute terror, because radio was a new technology and people were just channel surfing. It came across this thing in the middle, and then assumed it was a real report of an invading army from Mars, and they panicked. But here's the real story. It seems that about 2,000 people wrote in letters complaining about the show, but very few of them seemed to actually think it was real, which makes sense because in 1938, almost 80% of US homes had radios. This wasn't new, people were already very familiar with radio plays, but when newspapers heard about the complaints, they spun it into a story of full-blown panic because of course, newspapers were threatened by radio and looked for any opportunity to malign the new technology, and the story stuck.
Jason Feifer: Okay. I have two more for you. Second to last one. You know the expression rule of thumb? People have told me, as maybe they've told you, that this originated as a rule about domestic violence. The rule was a man could beat his wife with a stick no wider than his thumb. Well, I have good news. This was not an actual rule anywhere, but bad news, someone did actually want to make it a rule.
Jason Feifer: The phrase rule of thumb is first known to appear in writing in 1685 in a sentence about how Christians, "Build by guess and by rule of thumb," by which it just meant roughly. Nothing scandalous there, but then a century later in 1782, an unpleasant British judge named sir Francis Buller wrote that a man could beat his wife with a stick no wider than his thumb. It doesn't seem to have established any sort of legal precedent in England, but it did trigger a lot of public mockery, including cartoons calling this guy Judge Thumb, though, to be clear, it was also basically totally fine for men to beat their wives at the time. So like I said, some good, some bad.
Jason Feifer: And now finally, one more thing you thought you knew but didn't. Here's the story as we generally know it. The ancient Romans were so glutinous, they would literally stuff themselves full of food and then go vomit it up so that they could sit down and eat another meal. And this was so common that there was even a specific designated room for all the vomiting, and it was called the vomitorium, but here's the thing.
Caillan Davenport: Yes. So we love the idea of Romans as excessive and decadent. So they have extravagant meals where they're sitting around, waited on by slaves, and there's women attending to them.
Jason Feifer: This is Caillan.
Caillan Davenport: My name is Caillan Davenport. I'm Associate Professor of Classics at the Australian National University.
Jason Feifer: His area of expertise is Roman history and culture. And he says, look, most people in Rome lived on a subsistence diet. There was no gluttony going on, though the aristocracy of course, did get to enjoy themselves. All the same...
Caillan Davenport: The idea that there was a special room where they went to throw up the contents of their stomach so they could eat even more is a complete myth.
Jason Feifer: So where did it come from? Well, let's start with where the word vomitorium came from because it is an actual word.
Caillan Davenport: So the word vomitorium itself first appears in the fifth century AD in a work called the Saturnalia, written by a late Roman Senator called Macrobius.
Jason Feifer: It's basically a book of fun facts that you can use it at dinner party, kind of like this podcast episode you're listening to.
Caillan Davenport: And he talks about how poets use the verbs, WOMO, I throw up.
Jason Feifer: Which means, yes, if you have too much of a fear of missing out, you can totally WOMO from FOMO.
Caillan Davenport: Or WOMITO, which is, "I keep on throwing up." And he talks about how poets don't always use that in the sense of throwing up food, but metaphorically so that people can spill out of a room or be vomited out of a room, of a busy room, or that waves, for example, could be vomited up upon a beach.
Jason Feifer: So basically, we've got ourselves an entry level exercise on metaphor, but with a heavy emphasis on vomit. To illustrate the point, this fifth century book explains that poets might describe the entrance and exit of an amphitheater as a vomitorium because...
Caillan Davenport: The passage itself vomits out the audience in the same way that like from a modern sports arena, once the game's over, everyone sort of spills out onto the street.
Jason Feifer: Though, of course today, depending on how many drunk Boston Celtics fans there are, people might literally WOMO at the metaphorical vomitorium. And if they're Cleveland fans, they might...
Caillan Davenport: WOMITO, which is, "I keep on throwing up."
Jason Feifer: So how did the myth of the actual vomit-filled vomitorium appear? Well, it seems to be a complicated mix of things. Here are just a few. The 12 Caesars, which is a set of biographies of Roman emperors written in the year 121 does describe Emperor Claudius intentionally throwing up after meals, but it's not clear if that ever actually happened. Then in the 16th through 18th century, doctors started to use the word vomitorium to describe a powder or liquid that people can drink to cleanse their stomachs and bowels medically, for medical purposes, not for gluttony.
Jason Feifer: And in the 1800s, when a bunch of wealthy explorers started digging around Rome and excavating these ancient homes with lots of rooms...
Caillan Davenport: They liked to assign special names to each of the rooms like, "This is where that happened. This is where this happened." So they could show their other aristocratic friends.
Jason Feifer: And people became fascinated with what they believed to be the excesses of Roman life, and somehow all of these different elements and probably more snapped together, we got the story of the vomitorium, which never really happened.
Jason Feifer: So, okay. What did we just accomplish here? I threw a lot at you. What was the point of it? Well, we got to see...
David Rapp: Over and over, and over again.
Jason Feifer: How things that feel true are not always actually true. And of course, like I said at the beginning of the show, this problem extends far beyond silly facts about lemmings and vomitoriums, and into the things that shape our understanding of our world, or that drive the decisions that we make, and that's where things get really tricky because...
David Rapp: Psychology research shows people have a really hard time and are amotivated to disconfirm what they think is true. So it takes a lot of effort, a lot of practice, and a willingness to be wrong, and that's hard. So you have to seek out the information.
Jason Feifer: Again, the voice you're hearing is David Rapp, a Professor in Psychology in the School of Education and Social Policy at Northwestern University, who studies people's interaction with and processing of inaccurate information, along with how they deal with that information, what the consequences of being exposed to that information might be, and how we overcome and establish more evaluative mindsets.
David Rapp: And our lab has been doing this probably for almost 20 years at this point.
Jason Feifer: As David said at the start of the show, this is a very human problem. We are psychologically more trusting of information that feels true or that is easy to recall, which is why, if we hear something repeated often enough, we begin to trust it. So it's now finally time to ask, what are we supposed to do so that we're really filtering for truth? Is there some magic formula, some way of snapping people out of it? Well, there is an answer, but it's not really a magic formula.
David Rapp: One thing we really want to encourage people to do is when you have an opportunity to seek out information, seek out whether other sources make the same claims, provide evidence for the kinds of ideas that are being offered, sometimes it's called lateral reading, which is I'll read something in a particular place. Let me see if another place says the same thing and gives the same evidence, or it gives me even more evidence, so I can be more confident about whether an idea is true.
Jason Feifer: Although the challenge to what you just suggested there is people who are in communities that are oriented around misinformation, for example anti-vaxers, will always talk about the research. "Well, I did the research, I did my own research, go out and do the research." And so they are going to some sort of sources in order to validate or confirm the things that they're hearing. But of course, it's actually just steering them away from correct information.
David Rapp: Right. And that's actually doubly problematic because people feel like they're doing the research. They feel like they're engaging with the information. So that again is going to make them feel like they've done the hard work, so this must be true. One critical element in those cases is interrogating what the evidence is provided by the sources that you're seeking out. So when members of a community look for information that confirms their ideas, what pieces of evidence are they leveraging to say those ideas are true or not?
David Rapp: And if those communities are doing the right service to their communities, they should also be seeking out disconfirming evidence and looking to see what's the evidence? How is it obtained? What does it mean from an existing understanding? So often these communities refuse to seek out disconfirming evidence or out of hand will reject the evidence as plausible.
David Rapp: So it's not just looking to other sources, but when those sources make a claim, where do those sources derive the information that they're being provided?
Jason Feifer: Let me just say here, David is asking a lot and he knows he's asking a lot. He's basically prescribing a kind of non-stop research project where you look not just at one source, but then at other sources, compare them against each other, dig into the original sourcing that your information sources relied upon, and then make a decision about what to believe. And this is just not something the average person has the time to do or is motivated to do, or maybe even can do. And furthermore, we don't all want to start questioning literally everything that we see or hear because that is a conspiratorial death spiral.
Jason Feifer: So, okay. Let's ask it another way. What can we do not to counter every incorrect fact we ever come across, but instead just to set ourselves up for what I'll call, I don't know, maximum reasonable informational success. Well, look, even here, David doesn't have magic bullets. What he told me is something you probably already know, but of course, he says it with the authority to confirm that it really does work. You got to get outside your bubble. You connect with people who see things differently.
Jason Feifer: He said businesses are often saved by bringing in outside consultants, not because these people are geniuses, but just because they have a different point of view and force people in the company to confront the problems they've overlooked. But mostly, here's the thing that he said that really stuck with me. The thing that isn't a prescription so much as it is a mindset, and one we can all really just start using now.
David Rapp: I think we definitely want to have a skeptical eye towards information, but we also want to have the notion that when information is provided to us, that represents some form of data and we can evaluate it. So if we are hearing something that feels like it's too good to be true, then we probably will want to evaluate it. If we hear something that we're not sure whether it's true or not, we want to evaluate it.
Jason Feifer: In other words, if it feels true, take that as a sign that it could use a closer look. I like this because, well, it's just a nice way to process data. Someone tells you that a goldfish has a memory of two seconds and you could think, "Yeah, that sounds true," but why does it sound true? Well, let's look at the data. It sounds true because goldfish is very small and because you don't know a damn thing about fish biology. Maybe that's a good reason to look it up or just ignore it, but certainly don't repeat it.
Jason Feifer: Now apply that to, oh, things you hear on cable news. Here's my takeaway. We're all worried about misinformation today and we should be because misinformation drives terrible decisions and tears people apart, but we're missing the point if we think that this is just a today problem or is something that we can blame on one technology or one source, or one group, because the problem begins with the very natural way in which we process information.
Jason Feifer: It is the way that we are trying to do our best in our own ways to make sense of our world. And that can lead us to make some silly, but also some deeply terrible mistakes. And there is no easy solution to any of it, but the thing that got us into this mess can also get us out of it. And that's our brain and the way that we think, and the rigor we apply to what we know and what we do not know, and what we can and should always strive to do to get better at that as individuals and together. That's what feels true to me at least, and if you don't believe anything that I've said, well, go look it up yourself.
Jason Feifer: And that's our episode, but hey, we've talked a lot about goldfish memory on this episode and it's maybe gotten you wondering, should you keep a goldfish in a bowl now that we know it has a long memory? The short answer to that is no, please don't put them in a bowl, but the long answer is totally fascinating. I'll tell you about it in a minute, but first, if you love Build For Tomorrow the podcast, you will totally love Build For Tomorrow the book, it is an action plan for how to embrace change, adapt fast, and future-proof your career and life, and it combines lessons from this podcast with what I have learned from the smartest entrepreneurs of today.
Jason Feifer: It comes out in September, but you can pre-order your copy right now, and let me know if you do so that I can thank you personally. You can find it wherever you get booked, start by going to jasonfeifer.com/book. That is again, jasonfeifer, J-A-S-O-N F-E-I-F-E-R.com/book. And if you want to get even more advice and encouragement on how to adapt fast, then sign up for my newsletter. You can find that by going to jasonfeifer.bulletin.com. You can also get in touch with me directly at my website, jasonfeifer.com, or follow me on Twitter or Instagram. I am @heyfeifer.
Jason Feifer: This episode was reported by me, Jason Feifer, along with Adam Soccolich and Emily Holmes. And it was written by me, sound editing by Alec Bayless. Our theme music is by Casper Babypants. Learn more at babypantsmusic.com. Thanks to Margo Boyerdrive for sending me the Wikipedia page that kicked this whole thing off.
Jason Feifer: This show is supported in part by the Stand Together Trust. The Stand Together Trust believes that advances in technology have transformed society for the better and is looking to support scholars, policy experts, and other projects and creators who focus on embracing innovation, creating a society that fosters innovation, and encouraging people to engineer the next great idea. If that's you then get in touch with them. Proposals for projects in law, economics, history, political science, and philosophy are encouraged. To learn more about their partnership criteria, visit standtogethertrust.org/techgrants.
Jason Feifer: All right. Now, as promised, let's talk goldfish. So as we've already established, goldfish have long memories. As it turns out, they also have impressive cognition. Check out this experiment on another little fish called an archerfish.
Culum Brown: One of these experiments taught archerfish to recognize human faces, and it turns out that they can differentiate between 20, 30, 40 different human faces.
Jason Feifer: Can you differentiate between 20, 30, or 40 different fish faces? Probably not. That of course, was again, our fish expert, Culum Brown, and get this. When those fish learned a human face head on, they could still recognize the face when it was turned 90 degrees. Anyway, the point is, these little guys are smart and putting them in a bowl with nothing to do is torturously boring, which is why it's actually been banned by many countries.
Jason Feifer: Studies have found that when fish are in captivity, they suffer from stress and anxiety, but...
Culum Brown: What is interesting is that if you enrich the environment of a fish, its behavioral repertoire goes up massively. And if you test them on learning and memory tasks, their capacity for learning and memory also increases if they're living in interesting complex environments. And it turns out that if you look at their brains, their brains are also changing. So fish brains are actually renowned for being incredibly flexible.
Jason Feifer: You want smarter fish? Create smarter environments. I bet that works for humans too. Thanks for listening. I'm Jason Feifer, and let's keep building for tomorrow.
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