The Rest Is Science - There Are Four Ways To Lie

Episode Date: February 17, 2026

Is deception a uniquely human trait, or is the natural world built on a foundation of fraud? When a cuttlefish shifts its skin to mimic a female and sneak past a rival male, this may be deceptive but is it telling a lie? Professor Hannah Fry and VSauce's Michael Stevens explore the evolutionary biology of dishonesty across the animal kingdom. What is the neurological difference between a biological reflex and a calculated bluff? What kind of cognitive processing is needed for true artifice, and are human beings the only creatures on earth who possess it? Moving from tactical falsehoods by the Adélie Penguin, to the complex betrayals seen in Macaques and Great Apes, Hannah and Michael apply evolutionary game theory to the wild to evaluate the psychology of false signals and the battle between perception, manipulation, illusion and power. ------------------- For more information about Cancer Research UK, their research, breakthroughs and how you can support them, visit ⁠⁠https://cancerresearchuk.org/restisscience⁠⁠ Cancer Research UK is a registered charity in England and Wales (1089464), Scotland (SC041666), the Isle of Man (1103) and Jersey (247). A company limited by guarantee. Registered company in England and Wales (4325234) and the Isle of Man (5713F). Registered address: 2 Redman Place, London, E20 1JQ. ------------------- Find The Rest Is Science all over the internet by ⁠⁠clicking here.⁠⁠ ------------------- Video Producer: Oli Oakley Video & Social: Bex Tyrrell Researcher: Hannah Dodd-Vastiau Assistant Producer: Imee Marriott Senior Producer: Lauren Armstrong-Carter Head Of Digital: Samuel Oakley Exec Producer: Neil Fearn Learn more about your ad choices. Visit podcastchoices.com/adchoices

There's more to life than finding the perfect car. But finding the perfect car can help you get the most out of life. Like the SUV that handles everything from drop off to off road, and the car that hulls groceries and hockey teams, or the van that's gone from just practical to practically family. Whatever you want, wherever you're going, start your search at autotrater.ca, Canada's car marketplace. Olympic dream starts somewhere. At first, it's just potential. But over time with the right

support and a few breakthroughs, it becomes something more. Make RBC Training Ground your breakthrough moment. Start your journey to Team Canada today at rbc trainingground.ca.cai. Welcome to the rest is science. I'm Michael Stevens. And I'm Hannah Fry. And Hannah, I have a confession to make. I lied to you. Excuse me? Or at least I was I was untruthful. Go on. And I need to get this off my chest. So if you remember the day of the photo shoot, you brought me some iron brew, like giant

bottles of iron brew, because I had never had it before. And I was so touched by your gift that I realized I should have brought you a gift. Now, I brought the swords of truth with me because I wanted to play with them. And I said, oh, wait a second. I could give these to her. and I'll say that I brought them for her and it'll look like we both got gifts for each other. So the rest of my trip,

I didn't have my swords of truth to play with. But you did have that internal little nugget of joy knowing that you've made me happy. Okay, yeah, that's worth it. And I can always get another set of swords of truth. On the flip side, Michael, what I will say is, as a good Catholic girl, I've never lied to you ever.

And I appreciate that. Only one of us can feel smug. And you probably feel better because now that I've made that confession, I don't feel better. I feel like I've just admitted to being kind of a cruddy, thin person, you know? It makes you human, Michael. It makes you human. But does it? And that's the rub.

That's what we're here to talk about today. Can only humans lie? Or can other animals on this planet actually tell lies too? This episode is brought to you by Cancer Research UK. So when most people think of naked mole rats, their unusual relationship to cancer probably isn't the first thing that comes to mind. But maybe it should be because it is incredibly rare for them to develop cancer, which could be partly down to their unique immune system, or it might be the way that their cells respond to damage. So scientists are studying their biology for its cancer-fighting secrets. It's a reminder that discoveries can sometimes come from places you don't expect.

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Okay, so this is what we're looking at today. Can animals lie? And I think it's going to be a very short episode because obviously, yes, there is an incredible amount of deception in the animal kingdom, Michael. This is going to be a very easy one. Okay, there is a lot of deception in the animal kingdom, but is there a lot of lying? I mean, I think it depends on where you're setting your goalpost here. I mean, stick insects, they're pretending to be sticks. You've got butterflies, they've got false eye spots on their wings.

You know, venomous snake species that are kind of hard to tell apart because loads of other creatures copy them pretend to be all venomous. That's sort of, well, it's definitely deception, isn't it? It's definitely deception. Okay, yeah, like camouflage, all right? But I love what you said about the stick insect, that it's pretending to be a stick. Is it pretending to be a stick? That seems to give it a lot of agency.

It can't help the fact that it is stick-shaped. That is involuntary deception. It cannot help it. It's just the way it was born. A camouflaged animal is not deciding to deceive. It's just natural form is deceived. Okay. So are we saying that this is the most basic level of deception?

then this idea of like camouflage that doesn't actually involve any behavior. Yeah, that's right. Like the animal cannot be otherwise. It just always is in that deceptive state. An insect that looks like a leaf all the time. I think that's like bare bones lowest level deception. And maybe it's a lie. Maybe it's not.

But I think like maybe we'll have to be able to answer that by the end of this episode. Because okay, I guess there the deception is not happening by the creature at It's more like a meta-level evolutionary deception that's happening. That's right. Whereas I think if the animal can sometimes do the deception but sometimes doesn't, and that's triggered by certain events, that feels like a little more complex, an animal that looks like a delicious treat until a predator comes by and then it changes into looking like a stick. That's a little bit more complex than always looking like a stick.

And we should say that a lot of different researchers have tried to make a taxonomy of deception. And so we're going off of a lot of different lists. Robert Mitchell's is really famous. But I think we can all agree that there's a difference between a animal that from birth, or at least for its entire adult life, looks like something it isn't, versus an animal that behaves and reacts in a way that's deceptive. And already the examples that you're giving there, I mean, I think chameleons like spring to mind immediately

that they can just camouflage themselves in with the surroundings. But it's sort of a pre-programmed behavior. It's not like sort of saying, today I'm going to be pink, right? Right. It's not like in the Disney films where it just, you know, has an array of colors. It's reacting to its environment in a way that it was always genetically predisposed to do. That's right. That's right. So whether or not it has a choice, we don't even need to answer.

we can at least agree that it's different than an animal that is always deceptive. Like the eye spots on a butterfly, they are always there. It's actually responding to its environment, sometimes more truthfully, sometimes more deceptively. Okay, well, let me give you another example then, because there are definitely some examples of animals making an active choice to deceive. The cuttlefish is a perfect example of this. cuttlefish which for most of my childhood I only knew as something that you put in a parrot's cage. But it's actually this creature that lives off the western coast of Australia, the biggest cuttlefish in the ocean, this particular species of it.

And also really dramatic this particular animal. So often these creatures, they get called the chameleons of the sea because they are incredibly good and quick at changing colour. They can camouflage themselves to the background. But that can come in very handy when they want to engage in a particular type of deception. Because there are four males for every one female, right? The females know this. They are extremely picky about who they'll mate with as a direct result of this. And most of the time when mating attempts happen,

what happens is this large male will sort of come in and approach the later from the side, and it will spread its arms and then it will grab the female's head, which, I mean, sex as it sounds, about 70% of the time it results in a rejection from the female. Okay, so, you know, no, no, you need to woo her. You need to put on some Barry White Cattlefish. You need to learn. Anyway, here's the thing, right? So there's obviously incredibly high competition among males for mating rights over females,

and especially when you have this high chance of rejection. the larger males, what they end up doing is they basically become full-time bodyguards around their females. They sort of like shove away these smaller males who dare to come anywhere near. And to get them around that, the smaller males,

they have this act of deception that they engage in. So what they do is they like, change their colouring, change their arms, basically mimic being like a cute girl, get in the Harim, effectively,

in amongst them. all of the other females while the big male either isn't looking or mistakes it for a female. And what can happen sometimes is that the larger kind of alpha males will approach what they think is a female grabbing their head, etc. only to find out that it's actually a male in disguise, a sneaker as it's known. And from there, I mean, they have at least a chance to mate, which they otherwise wouldn't. So there's some researchers last year who were looking at these at these creatures and they were following five different sneaky males. One of the sneakers just got rejected straight off.

One was caught off by sort of the alpha and was chased off. Three, got close enough to the females in order to attempt to make with them. And two became fathers, new fathers to a brood of baby cut of fish. So, you know, it's a tactic and it definitely works, right? Yeah, yeah, yeah, yeah. Okay. Now that feels like we're going a level deeper into this deception. now. Because, okay, sure, it sort of doesn't really have that much of a choice because the sneaker males, if they want to have babies, I mean, this is their only option, really. But at the

same time, it feels like it's making a behavioral, it feels like there's some autonomy that's involved in this. Yes, it could be otherwise. A stick bug will always look like a stick, but a cuttlefish could, you know, not successfully do the deception dance and, you know, lose out and and not have kids. But it's still in the cuttlefish a very instinctive, it's born genetically with this ability to react. I think to go a level further, we need to find animals that do not naturally from birth have an instinct to deceive, but can learn things that are deceptive. Okay, I think I have an example for you that brings this on one step further. It's actually one of my favorite natural history stories of all time.

I've been holding this one in my back pocket for an opportunity to bring it up and now that day has finally come. All right, pull it out. Pull it out. Okay, so in 1910-ish, there are all these expeditions to the Arctic regions, right? And George Murray Leivick went off to go and study a daily penguins in particular. He found that they got involved in all kinds of like crazy behavior. So he sort of went off and he was expecting these really cute sort of tuxedo wearing birds

that acted like proper little gentleman in these Arctic regions. And then he observed these hoologun males, his words not mine by the way, using all kinds of, to the Edwardian eye, horrifying behaviour. And some of this, I think, remains horrifying to this day. So necrophilia, right? Bad. Coercion, particularly around sexual activity, also bad. gang behaviour, also I would say bad,

and to the Edwardian eye, homosexuality, which I, if I remember my history correctly, they didn't like at the time. They did not like it. The gay penguins, man, they're a part of history. Aren't they with their little tuxedos? Anyway, he came back, he wrote up his notes, and they all decided that they were too scandalous

to be able to publish them for Edwardian society. So he translated all of the dark bits into Greek in case a passing lady happened to be looking, so she was extremely well-educated and couldn't translate them. And then they ended up deciding not to publish them at all. They hid them in sort of the depths of like scientific archives for a hundred years.

They were finally uncovered in 2012. He was so disturbed that he wrote in his notebook. There seems to be no crime too low for these penguins. It was very judgy of him. Anyway, that was the males, right? That was the sort of the hooligan males. The females, meanwhile, were engaging in sex work. Okay, so, I mean, it's been described by some people as pebble prostitution.

But essentially, they were exchanging the opportunity to copulate with a male for a pebble that they had. So, wait, they were paying for sex with pebbles? Yes, yes, exactly. Because penguins, they need these stones for their nests. This is not the deception part, by the way. I'm coming on to the deception part in a second. But penguins, yeah, they need these stones for their nest. They're quite hard to find.

they're often really prized. So what can happen is that you do get some females who will copulate with a male in exchange for a pebble. That happens. But crucially, what happens sometimes is that some females who actually have a mate who is guarding their nest will go off and engage in a fake courtship bow with the male, essentially to lead him on. she'll wait for him to present a stone and then instead of like going off to sort of complete the activity

she will grab the stone and then she'll run off back to her mate who's guarding the nest. So she steals the money. She steals the money. Doesn't perform the service that was paid for. Exactly. Beautifully put, thank you. And is this something that they have to discover or from birth are they like programmed to be

little tricky tricks. Little tricky. I mean, remember what the boys were doing. Okay, so let's not be too judging about the females. But it's really hard to know, I guess, right? Like, is this? It's really hard to know because is this something that one penguin came up once and others picked up the behavior and copied it,

or is it something that's like an innate skill? Really good to know. But what you can definitely say is that I think this goes on one level from the cuttlefish because this is no longer just a mimicry of your physical shape. This is getting

another member of your own species to make a false prediction about your future behavior in order to extract something from them. Maybe. I'm not sure if I would start talking about false beliefs yet. Oh, okay.

I definitely think that it is a more complex behavior. We're using objects now. We're using pebbles. But I think that whenever an animal, like through trial and error discovers, oh my gosh, if I lay down like this, it leaves me alone. And it's discovered feigning death. Right. But until it tries that, it won't do it. But once it tries it and realize it works, it's learned it. That's like a new, kind of deception where you weren't born to do it, you've learned to tell this kind of lie. Okay, so Levik did have an opinion on this. He wrote that he thought it was an occasional spontaneous tactic rather than a socially transmitted tradition. Ah, but lying can, especially in humans,

be a socially transmitted tradition. It can be a thing where we go, you know what? You know, my mom lied. And that's why I'm such a liar today. Yeah, it was my upbringing. I mean, the great example is, it's my upbringing. The example also is like, how are you? I'm fine. That's a socially transmitted traditional lie, right? Yes, yes.

And it's also like a kind of lie that we sort of need. So that's the key point for you then, is it? This idea of it's got to be an active choice. It's got to be an occasional behaviour. And it has to be something that you discover. No, no, no, no. I'm not saying it has to be any of these things. I think that there's just a difference between them. And whether or not something is an active choice, that ascribes agency to the animal. I think that the cuttlefish might not be choosing to camouflage or not. As far as we know, it could just be an instinctive action that they have no awareness of. We could also assume that they're choosing to do it and they could choose not to. But we would have to design experiments to somehow look inside their minds to know.

know if they are intending things or if they're a very complex biological machine. But we can say that there's a definite difference between the stick bug, the cuttlefish, which sometimes is camouflaged and sometimes isn't, and behaviors that involve objects like the penguins. But then even more complex behaviors that involve discovery, trial and error and learning. where one species over here does it, but the one over here doesn't because they just haven't discovered it yet.

I mean, you definitely see that in macaques, right? So this is like rhesus macaques. They have these very rigid hierarchies. Again, they have like a dominant male. And they have cries that they give out if a predator is nearby, like a hawk, for example. But occasionally, the researchers who've observed them, they find that sometimes there'll be a cry that goes out for a hawk nearby.

and there's no hawk anywhere and all the macaques will sort of run away and then one clever little monkey who's almost always a low-ranking male will run in and like steal a little bit of food before the others come back but I mean that is the sort of like functional deception that you're describing I think

okay interesting so the macaques learn to do this they learn that hey when that sound happens we all leave but if I make the sound when there's no If I'm a macaque who cries hawk, then the food or whatever I want is left unguarded and ha ha.

Like they come to this realization and then take advantage of it. Yeah, it's strategic, right? It's like it's this intentional directed behavior in order to get something that they want that they're not born with. They're not born with that ability. It's something that's learned. Okay, so these examples of animal deception are all, they're really funny. You know, they're all really cool.

But at the end of the day, what I'm looking for and what a lot of researchers are looking for in philosophers is deception where the deceiver knows what they're doing and could be held responsible for it. Like the cuddlfish, the macaques, is this just behavior that's following rules? Or is there actually a deeper understanding of you are going to have a different belief in your head because I put it in there and it's not true? That's when I think we get into definite lie territory. And I think we should take a look at that after the break. Hello everybody and welcome to the Book Club, a new podcast from Gollhanger. Hosted by me, Dominic Sambrook. And me, Tabitha Siread.

As some of you may know, I've been Dominic's producer on The Rest is History. And we even did a mini-series last year about all things books. And since we enjoyed that so much, we have decided to roll it out as its own show. So it'll be coming out every Tuesday. We'll be doing a different book each time and digging into all the stories behind them. And we are going to be talking about

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you will be able to pretend to people that you've read them. That is the key thing. And either way, whether you read them or not, we hope that you'll learn lots of fascinating facts, you'll do lots of great stories, and maybe Tabby, the odd laugh. We will be looking at thrilling, gothic bodice rippers like Wuthering Heights and Frankenstein,

as well as iconic stories like The Great Gatsby or Little Women. And then also some more modern stuff. So Game of Thrones, normal people, the Hunger Games, Hamnet, all manner of exciting stories. So please join us on our journey into all things books, wherever you get your podcasts. Just search for The Book Club every Tuesday and hopefully we will see you there. This episode is brought to you by Cancer Research UK. We often think of beating cancer as treatment, but imagine stopping it before it begins.

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It shows what long-term research makes possible. For more information about Cancer Research UK, their research breakthroughs and how you can support them, visit cancerresearchuk.org forward slash the rest is science. Amazon presents Jeff versus Taco Truck Salsa, whether it's Verde, Roja, or the orange one. For Jeff, trying any salsa is like playing Russian roulette with a flamethrower. Luckily, Jeff saved with Amazon and stocked up on antacids, ginger tea and milk. Habaniero? More like habanier, yes. Save the everyday with Amazon. Okay, it sounds like here we are saying that if you're going to be a proper liar,

you've got to manipulate with intent. I guess I'm still unsure where I want to fall. I think that we can definitely agree that there are different levels and types of deception. Here's the definition of lie from the dictionary. Lie. Resting position on a supporting surface. Wow, that's a curveball. No, but here's something interesting.

I was, as I was, I'm not just joking. I looked into this. Why the heck does the word lie have two meanings? Why can it mean to lay flat on a surface, but also to tell an untruth? Do you know the answer? No, tell me. There is no answer. They came from completely different words that meant completely different things.

And over time, they both came to be pronounced the same. Both the words, to tell an untruth and to rest on a flat surface sounded kind of similar thousands of years ago. And then they just came to both be the same. let's do a little bit of word stuff because I can't help myself. Please, please. Where did the word lie as in like

to tell a mistruth come from then? What's the origin of that? Okay, so to speak falsely, to tell an untruth comes from the Middle English lying or lean, which comes from old English lagan, earlier Leogon, which is to betray back and back and back.

But then to rest horizontally comes from lion, which is still the same in Middle English, but in old English it was lech-gon with a siege and they're they're yeah I mean they're both just from different words I think there's something interesting there about that it originally came from the word betrayed because that does definitely have negative connotations in the same way as you lying about the present that you gave me I don't I mean you didn't betray me well that's right But I think the negative connotation is really important.

When humans lie, we judge them much more harshly than we judge these other kinds of lying that we've been talking about. When I see a stick bug, I don't put my nose up in the air and go, the liar. You know, you're not a stick. That's just despicable behavior. You know, what is the insect world coming to? You'll just pretend to be a stick. But when a person lies, when they lie to their children, to their children, to their, spouse, you know, that's like, whoa, this is, like, I hope this isn't contagious. This is morally

disgusting. And so there's a huge leap in just the way we behave towards non-human animal deception and human deception. Why is that, though? Where did that come from? So it's not like the word used to be betrayed. It's more like these words were all meshed together and you can translate them in different ways depending on the context. So that's why I kind of hooked on to the negative connotation of it. It's like, yeah, they're not related. I thought at first maybe the, to lie, like, to lie down was where we got the word lie to tell an untruth. And somehow it meant to like not be straight up and down. But no, they come from different words that over time came to be pronounced the same. Okay, so I get so distracted when I research. I wound up

spending hours looking into the difference between lie and lay. Do I, do I, do I, do I, lay the pencil on the table or lie the pencil on the table. Am I, when I get into bed, am I lying down or laying down? Do you know the difference? No, I just use them interchangeably. Is there an actual difference? There's an actual difference. And the difference is that to lay means to put something down.

Okay? Lay involves an object, something else that you are acting on. You lay a book down, but to lie means to be in a resting position. So you lie down, but you lay other stuff down. Okay. So you can lay a child down and then they are lying. That's exactly right. Yes.

And then not to get too into the weeds here, but this still hasn't changed. Dictionaries still haven't changed this. But the past tense of lie, meaning to lie down, is lay, not lied. So I might say something like, well, yesterday I lied down on the couch. That's incorrect. It should be yesterday I lay on the couch. Someone needs to go through those dictionaries and clean them all up, make it a bit simpler. Well, that's the classic debate between the prescriptionists and the descriptionists.

Some people say, look, there are certain rules, and we need to follow them. And others say, no, the only rule is what do people do? And when we should just be describing how people use the words, and that's the correct usage. So, you know, that's a topic for another day. But let's get back to actual lying, meaning untruths, because I want to go into the realm of theory of mind. This is when for me, deception really starts to be a lie. So it's one thing to be born looking like a stick.

It's another thing to act or learn that certain behaviors help keep you safe, that to us might look like deception. But at the end of the day, it's really hard to get into the mind of an animal and know if it actually is aware of what it's doing. Is it aware that when it pretends to be dead, the predator goes away because the predator thinks in its own mind that you're all right? dead and not worth chasing, this is what theory of mind is. And which animals on Earth have it is still very much up for debate. We, being humans, can introspect and go, well, I definitely have it. But here's what theory of mind is. I love this definition.

It is the ability to understand that other organisms aren't just responding to reality. They are responding to their beliefs about reality. Nice. And that those beliefs can be different than yours, that their feelings, what they know, and their goals are different. Because if you're an animal, whether you're human or not, it's obvious that we all, I shouldn't say obvious, but it's been shown that animals understand that other animals

can see the same things they can see, can smell the same things they can see. But how do we know if animals know that other animals can think and know the same things that they know? So this is what a theory of mind is. And if a creature has a theory of mind, then they can really like lie in a way where it feels like they're responsible and they're kind of bad. They're kind of sinners. Because this is something, I mean, young children don't have a fully formed theory of mind, right?

Something that comes along as part of their developmental process. It's all still, there's still so much we need to learn. But yes. commonly it's stated that like under the age of four, children don't seem to have a theory of mind. And one of the most famous ways that this is tested is by testing what are called false beliefs. Can children, human children, understand that people who aren't them can believe things that are not true? So, for example, the most famous test is called the Sally Ann test. It's a psychological test that can be given to anyone of any age.

where you tell them a story about two girls, normally named Sally and Anne, that's where it got its name from, and the story is that Sally has a basket with a little lid on it, and Anne has a box with a lid on it. And Sally shows up, and they're both together, and Sally has a marble, and she puts that marble into her basket and closes it up.

And then Sally leaves. And while Sally is gone, Anne reaches in, takes the marble out of the basket, and puts it in her box, closes it up. Now, Sally returns, and you ask the child, where will Sally look for the marble? Now, clearly, to us,

we say, well, Sally is going to look in the basket. That's where she thinks it should be. That's where she put it. She doesn't know that Anne moved it. But under about the age of four, children will say, oh, she's going to look in the box because that's where it is. I know it, so therefore Anne knows it,

and Sally knows it, and everyone knows it. And I, this makes sense to me because I remember when my daughter was very young, like two, three, four years old, she would sometimes tell us about a dream she'd had and then forget details and ask my wife to help her finish the story. What was that dream about?

Adorable. And we were like, oh, no, no, no, you have a different mind than us. We don't know. I don't know what you're feeling. This is, I think, one of the reasons why kids make absolutely terrible liars, right? I should tell you, this is one of like the most

genius things that I've ever done in my entire life, right? Which is when my daughter was very young, under four, I told her that every time she lied, a light would shine out of her eyes. Ah. Which is, I'll admit, slightly dangerous. A lie? It's a lie. But what would happen is that if she had done something

that she wasn't supposed to do, you know, stolen some chocolate or whatever, she would come into the room covering her eyes, like this to tell me. Oh my gosh. See. Okay. That's devious, but it's also really clever.

I use a trip with my daughter. She doesn't like to tell me about her day, but I once, it was kind of late at night and she didn't want to go to bed. And I'm like, well, let's see if you're tired. It's well known that when children are tired, they can't tell the truth. And then I asked her a question about her day and she thought really hard and she told me exactly what had happened. Yeah, it was great.

I want to mention, though, that these studies that show that under four children don't always seem to have a theory of mind are still kind of controversial because it's unclear whether it's exactly their theory of mind hasn't developed or if it's literally just that it's hard to ask questions of kids who are two and a half. You know, when you tell them a hypothetical, like Sally returns, where will Sally look? they might be thinking where should she look or where would I help her look. Before their language is fully developed, it's hard to know if they're truly understanding what we're asking. There's a lot of other reasons behind this.

But I think the research is fascinating and making the experiments better and better is like, I just love this. I love reading the details of how we do it. So let's get into non-human animals, okay? But this is it, though, right, because if it's difficult to design these kinds of experiments for two and a half your own kids, Designing them for animals is way harder. Okay, so non-human animals. Like, let's look at some of our closest relatives, chimpanzees. Do they have a theory of mind?

Well, we've developed versions of the Sally Ann test for apes, and they don't pass. Okay? They just, they don't pass. Another famous version involves taking a box of candy and asking a child, what's in here. And they'll be like candy. And then you open it, and it's actually. full of pencils and then you close it back up and then their mom walks in and you go, what is your, what do you think your mom's going to say is in here? And they go, well, pencils. Okay. So you can,

you can design experiments like that for chimpanzees, but, you know, it's hard to know with an animal that doesn't speak English or speak a language, you know, exactly what they think you want them to do and what they mean. So some really clever studies have been designed that have looked into theory, of mind in chimpanzees. So in 2016, a fantastic study was done that I think did this really carefully. They had chimpanzees and bonobos and orangutans and they brought in these fake haystacks, like little haystacks that were hollow inside so a person could go inside them. And they put two of them in the enclosure.

Let's call one the left haystack and one the right haystack. And the ape is watching this. First of all, this whole thing sounds really hilarious because it has to be. You cannot go up to a chimpanzee and be like, hey, look at this puzzle. Because the chimpanzee will say, I don't care and move away. So you have to surprise it. You have to do novel things. So what they did is they had one of their researchers dress up like a gorilla.

They called this the King Kong character. And by the way, it makes the videos and images from the experiment so friggin' confusing. Because I can never tell if I'm seeing a real ape or a real ape. or a researcher dressed up like a gorilla. But here's how the experiment worked. First of all, they taught the ape that when this King Kong character runs into one of the haystacks, a human who watches them is going to take a broomstick and come up and hit the haystack that they're in and then go back in. So the ape loves watching this.

It's very fun. We know they're paying attention. Then they started to do an experimental condition where they had the human watch. and of course the chimpanzee subject is watching, King Kong comes in and runs into the left haystack. And then the human goes inside to get the broomstick. And while they're inside behind these opaque walls, King Kong leaves the haystack and moves into the other one.

Oh. And then the human comes back out. So it's the same as the Sallian thing? Yes. Mm-hmm. Now, by using infrared eye trackers, the researchers could check immediately. Immediately down to the millisecond where the subject chimpanzees eyes went because it wants to see the broomstick hit the haystack

Is it going to look at the one that has King Kong in it or is it going to look at the one that the human thinks King Kong is in? I forgot one really important thing because you might think well of course the The chimp is just going to look where King Kong is because that's that's important like maybe King Kong is going to run out again. So actually what they had King Kong do is while the human was gone, King Kong left, went into a different haystack, and then left the entire enclosure. So King Kong is no longer in any haystack. Okay. Which means the chimpanzee subject has no reason to look at one haystack or the other,

because it knows that there's nothing in either of them. But will it remember that the human has a different belief, a belief that King Kong is still in that one? Or does it, where does it look? And as it turns out, the majority of the time the chimpanzees look where the human would think King Kong is. That is an incredible experimental design. I cannot even imagine how long it took for them to come up with that idea. I mean, that is the Sallian experiment, but done for chimps.

But done for chimps. That chimps have theory of mind or some version of it. Yes, they might have an implicit version. Like they might not be able to feel it. There may not be aware of it, and I'll get to that a bit later. But they certainly, at the level of their eye movements, anticipate creatures to act on things that might be just their belief and not the actual subject chimps belief.

So let me think about this then. So what does that tell us then? I guess it sort of says in a way that the apes know when someone else believe something untrue, even though they know the real answer. Like they're not just watching what happens. They are thinking about what somebody else knows, thinking about what somebody else doesn't know. Yeah, it's like a bigger, more detailed picture.

Maybe. It's certainly more detailed. Whether or not they know that the human has different beliefs than they do is really hard. Because there are researchers who want to make it very clear that they're never going to just accept. that like, yep, they have a brain like ours. Because it could be that there's this evil eye hypothesis

that the human just looking where King Kong went somehow contaminates that haystack. And so it's the haystack itself that is now imbued with an importance when the human is present. And so the chimp simply looks at that haystack because it's been imbued with an importance. And that would explain the look.

It doesn't necessarily mean the chimp looks because it thinks to itself, he believes this. He doesn't know. Oh, it's dramatic irony. The chimp might just be saying when that person is around, this is endowed in my mind with something. There's something important. There's some reason to look at it.

The chimp may not explicitly know or be aware. Here's the last experiment I want to talk about it. And I think that it gets even closer to helping us understand where chimps fall. And this experiment involved teaching chimpanzees to beg for food. So there was an enclosure where food would be put. And then there would be humans inside the enclosure next to a little hole in the plexiglass. And to get the food, a chimp had to put its hand in this kind of little cupped motion through the hole towards the human. And then the human would go and get the food.

You can use this to test which human will the ape beg from. They started to do some experiments where they would have two humans in the enclosure. and one of them would just be normal and the other one would have a big opaque bucket over their head or a blindfold. They couldn't see anything. A third human would they come in and hide some food somewhere in the room.

The chimpanzee sees that it's being hidden. Will they then, when it's time to beg for food, go beg for food from the human who saw where it was hidden or the human who had a bucket on their head and couldn't know where it was put? And as it turns out, they indiscriminately go one way, or the other. It doesn't matter. Oh. Wow. Okay. So that kind of contradicts. Half the time they go to the person who saw. Perhaps not directly. But I guess the automatic conclusion that you want to draw

from the haystack experiment, it's not, this experiment that you're describing isn't giving the same satisfying indication. That's right. That's right. And so the first experiment with the haystacks was actually designed after the bucket experiment. Because some researchers have said, well, here's the deal. Begging for food from a human, that is just so not a natural behavior of an ape. Whereas watching them hit a haystack with a brum, that absolutely is. Yes. No, being entertained is much more.

I'm sorry. So, yes, then there's a third experiment that I think really solved that problem of things being unnatural, like following a King Kong or begging for food from a human. Tomicelo did a study, and I think this one's just. so brilliant where they had a room, a middle room with two rooms on the side. One contained a dominant ape and the other contained a submissive ape. Okay, so they knew each other. And the submissive one knew that the dominant one is in charge. This is a very natural primate behavior. Okay. And what they did is they had two windows that they would open and so both

apes could see each other. They could see that the other one is seeing and then they would do things in the room. Like they might hide food in a certain location while both are watching, and then they'll open the doors and let them both go into that room where the food is hidden. If the submissive chimp saw the dominant chimp watch where it was hidden, the submissive chimp wouldn't even go to the food. They would let the dominant one go get it. But if when they hid the food, the submissive chimp could see and the window for the dominant was obviously closed, then when they open the doors, the submissive one goes to the food. Right. So, So there is something, I mean, look, you always have to be careful about the way that you interpret these things, but perhaps some evidence that the chimp there is thinking about what the other chimp could see and whether or not it could get away with its behavior.

Yes. Again, it could be the evil eye hypothesis that if the dominant chimp has looked at the food, the food is contaminated, and that's all the chimp knows. Don't eat that food. They've tried to do some different experiments where they have the dominant chimp look, see where it's hidden. they block the dominant chimps view, allow the submissive to still watch as they re-hide it, and when that happens, the submissive chimp does go and get the food.

So it could be that the evil eye hypothesis isn't true, or it could be that the evil eye actually means food in that location is off limits. Basically, there's a lot of pressure to make sure that we 100% know this is a theory of mind and not just a rule-based behavior. And we still don't know.

Science, baby. That's science and that's what makes it so good. But I think that, okay, at its core, though, I think when we talk about lying, it's this idea that it's about a manipulation of belief. That's right. There is one example of a gorilla, at least seeming to do that. And it's actually quite an old example. It's from the 1970s. This is San Francisco Zoo. There was a baby gorilla called Coco who got taught sign language by a young researcher called Penny Patterson.

And this gorilla could, you know, use hundreds of signs, right? She could name things. She could ask for food. She could, like, she had pet cats. She could talk about her pet cats. I mean, this is very San Francisco in 1970s, isn't it? She would do these things. A lot of the time, you know, the language,

that she was using was you could put it down to sophisticated begging, right? She was asking for things. And even if she wasn't directly asking for things, she was sort of like essentially instructing the handlers to do something that she wanted in some way. But there was one particular day where she had a sink in her room. I mean, why they're treating a gorilla like this, who knows, but she had a sink in her room and the sink broke. She broke the sink. And when she was asked by her handler, Penny, what happened to the sink? she signed the cat did it she pointed to her kitten and she said the cat did it now okay like from the outside superficially that looks to me like a human kind of lie right in the sense of it's the

manipulation of belief it's not very good lie it's the sort of lie that you get from a kind of two-year-old you know she's shifting the blame shifting the blame but you can't be i think because of everything that you've described and the fact that this is one instance in the 1970s you have to be absolutely sure before you start saying these things as as cold, hard facts when you're trying to infer things about animal behavior. Yeah. I love that story. And it's like clearly that ape knows that blaming the kitten might prevent a negative outcome or a consequence or whatever that they're afraid of. Whether or not they're doing it because they know that the humans have minds, or whether they think it's just A plus B equals C is what we're trying to get at. Yeah.

Is it just another form of sophisticated begging in a way? That's right. That's right. Predicting an outcome based on your behavior. I think after all of this, I want to make it clear that I'm sort of playing devil's advocate here. I think that we should always assume a theory of mind and animals because we should give them the benefit of the doubt and we should think that there's much like us as possible. In fact, I don't know what we're going to title this. episode. I don't know what the producers will do, but if they call it, can animals lie,

I've kind of got a problem with that, because of course they can. Humans lie. We are animals. And I don't like when people use the word animal to mean everything that's not us, as though we're not part of the animal kingdom. Like we own the earth, obviously. We're the ones in charge, and then everything else is an animal. Obviously animals can lie. Homosapians are a kind of animal. We're in the primate family. But what I'm saying is that to be devil's ad, I think it is good that a lot of researchers say yes, but did Coco lie about the cat doing it? Did Coco think you guys can be tricked and deceived? And I can place a false belief in your minds because your mind is different than mine.

Or was Coco behaving in a way that would change a consequence because of a rule that she had learned? Because I think that's the point, right? Human lying in the way that we mean it, that is about targeting the belief system. of another individual in order to change their future behavior, right? Yes. If you're kind of trying to define it, that's really what it comes down to. And I don't know if we will ever know if any other animals have that deep of a theory of mind and deceptive ability besides us, because we can't be other animals.

But let's go back to that bucket head experiment. Because I think that what fascinates me the most is that begging for the food is also a kind of question asking behavior. It's could you tell me this answer? Could you tell me where the food is? It's kind of exposing what the chimp thinks the person knows, what is in their mind that isn't in the mind of the other human. And because they don't seem to make a distinction between a human who knows where the food is and one who doesn't, maybe they don't fully understand at a conscious level other people's knowledge. And this ties in with a really fascinating fact,

which is that, yes, Coco could do sign language. Coco could put together an explanation that wasn't true. But Coco never asked a question. I spoke about this in a TED talk in Vienna a long time ago. And to this day, it's sort of chilling to think that no animal has ever asked us a question that are curious about things. they want to experience things but they have never been

they've never shown themselves to see others as sources of information in novel ways of course bees will gather around another bee to watch it do its dance to learn where the pollen is but that's a programmed instinctive behavior there aren't those like

novel hey you saw where the food went and by the way like hiding food in a cage is not my natural it's not in my DNA That's not a puzzle I have solved through natural selection. It's like a new thing I'm used to. They've never asked questions. And I think that once a species can ask questions, that's when it can tell lies.

I guess that's the point, right? Is that unless you can ask, what do you know? Unless you have that curiosity about knowledge specifically, you then, I mean, that's the foundation of what do you believe and then can. I change it, which essentially is the top level of lion. The top level. Yeah. And so while I'm going to err on the side of deciding that theory of mind is pervasive in the animal kingdom, because I want to give animals more respect, maybe even than they deserve. I'm not going to judge Coco for trying to pass the blame onto the cat because I think that they're not as responsible for what they say. Even if in a way they might know what they're doing,

I refuse to be judgmental to them about it. But if a human lies to me, don't do it twice is all I can say. Okay, well, I luckily have a much more liberal attitude towards lying. You can lie as much as you like, Michael. Oh, really? Just as long as it's good lies, okay? I want nice lies.

I want lies that make me feel better. I want lies that increase my overall happiness and well-being. All right. Okay. Well, if that's what you want, then how about, this. Hannah, I had a great time on the podcast today. I'm really glad we got to have this conversation. And I hope that all of you out there listening did too. Okay, all of a sudden, I don't know what's real anymore. You can leave us to fonder that. But that's a wrap on

this episode. Make sure that you are following the rest of science, wherever you get your podcast. Make sure that you are subscribing to us on YouTube. That's right. And if you have any questions you want to ask us, we might just answer them on field notes. So, send them to the rest is science at gollhanger.com. Email us. See you next time.