Quirks and Quarks - Great white sharks in hot water, and more…

Episode Date: June 19, 2026

Some of the oceans biggest, most powerful predators, like certain sharks and tuna, are “mesothermic” or warm-bodied. Running hot allows them to rapidly convert their food to energy and heat, helping them swim faster and hunt in cold waters. But that advantage may become a disadvantage in a warming climate, meaning these fish need to find new ways of cooling off, or face a new threat to their survival.PLUS:Ancient Peruvians traded parrots across deserts and mountainsFrom the archive: David, Jay and Bob, and Quirks & Quarks' origin storySea cucumber 'zombie tissue' straddles the line between life and deathDream engineering may help you solve problems in your sleep

If you sold somebody a loaded gun who you knew was in a vulnerable state and they shot themselves. I think it is murder. Just because you're using the internet doesn't mean you get away with murder. I'm Damon Fairless, host of Hunting Warhead. This season, I take you inside the business of suicide, and the places desperate people go when they can't find what they need in the real world. Hunting the Suicide Salesman. Available now, wherever you get your podcasts.

This is a CBC podcast. Hi, I'm Bob McDonald. Welcome to Quirks and Quarks. On this week's show, how some of the ocean's biggest and most powerful predators may be at risk of overheating in a warming world. As fish get big, and particularly these warm-bodied ones, it's actually increasingly hard for them to lose their heat from their body. And a surprising discovery by sea cucumber researchers

that left them scratching their heads. We could tell that these tissue. were not dead. They're not decaying. They're continuing to reform, restructure, and persist. But are they actually alive? Plus, the Quarks and Quarks origin story, an ancient parrot trade route, and how dream engineering can solve problems. All this today on Quarks and Quarks. Sharks have been around for millions of years. They've lived through five mass extinction events, so we know they're pretty resilient. But are they resilient enough to handle the next crisis coming their way? Warming waters? Some of the ocean's biggest, most powerful predators, like great white sharks

and bluefin tuna, are mesothermic, or warm-bodied, which means their bodies run warmer than your average fish. Warm-bodied fish are rare, accounting for less than 0.1% of all fish species, and running hot allows them to rapidly convert their food to... energy and heat so they can swim faster in cold waters. But that advantage is becoming a disadvantage. A new study of these warm-bodied fish found they're running hotter and now need more energy and food than their cold-bodied counterparts. And that means that in a warming climate, these fish need to find new ways to cool off or face a new threat to their survival. Dr. Nicholas Payne is a zoologist at Trinity College Dublin in Ireland. He led the study.

Hello and welcome to our program. Gail, Bob. We're saying warm-bodied fish for some of these sharks and tuna. How's that different from warm-blooded? Warm-blooded is kind of a bit of a misnomer in a way. Some of the blood in their bodies is definitely warmer than the ambient water that they swim in. It's really just parts of their bodies that are kept warm. So I don't like to think of them as like all their blood is warm.

It's better thinking of them as just regions in their body are warm. And some species just keep the central core red muscles warm. And red muscles are the parts of the animal that helps them cruise for normal cruising swimming. Other species only keep their brains warm and keep everything else cool. Some only keep their eyes warm. But there tends to be a similarity in that they all end up being primarily top of the food chain, big, fast, athletic animals. Well, take me through your work.

How do you go about studying such a large shark that's swimming freely in the ocean? Yeah, so look, Bob, I mean, this is part of the fun, to be honest with you. I mean, when you have a 30-foot basking shark that weighs the same as a bus, logistical challenges, let's put it that way. So what we decided to do, rather than trying to catch the animal and bring it back to a laboratory, we turn the free swimming animal into a laboratory. So in other words, we take instrumentation, so senses that in our case is primarily measuring things like water temperature and body temperature of the animal, and we take those physiological

measurements of the animal while it's swimming naturally in its own habitat. So what did you find when you did get the data back off the sharks? First thing we saw was that they, basking sharks have warm bodies. The muscle just under their skin is significantly warmer than the water is. And that was kind of a big surprise to a lot of folks because mesothemes, when you look at them as a group, they tend to be top of the food chain. Great white sharks eating seals, mako sharks swimming at 100 miles an hour jumping out of the water and eating fish and squid. And basking shark is a slow swimming animal that eats. It's almost like a grazer.

So this is a little bit different to what we normally think of this group of animals, the mesothirms. but that was the first confirmation to ask, wow, this animal was actually one of these mesothems. So that was a really, really cool finding a few years ago. And then from then on, we slowly started to think more and more about energy. Tell me about that. I mean, what does this warmer temperature do to their bodies and their, well, their metabolic rate? Need a lot more energy and it makes them a lot hungrier. Like if your body temperature, Bob goes up by even just one degree or it goes down by one degree,

That's kind of a medical emergency. Our physiology is very, very precisely tuned to have one body temperature. But almost all animals and plants, their body temperature fluctuates wildly. So more than 99% of fish species, their body temperature more or less matches the temperature of the water that they're swimming in. And what we tend to see for all life is that as temperature increases, the amount of energy that that organism needs to do stuff, just to live or to grow or to reproduce or to maintain itself, as temperature increases, the amount of energy they

need to do, that tends to increase pretty dramatically. So if you're a fish that intentionally maintains your body at a higher temperature, you're probably going to need a lot more energy to be a living successful mesotham. And what we did in our study was we measured that cost, and sure enough, it costs a lot. It costs a lot to be a mesothemic fish. which means more fuel, which means more food that they have to find to keep that up. Exactly. Is there a threshold as we're hearing about the oceans getting warmer? Yeah, so Bob, great question.

This is one of the crazy things about this recent study that we published. Once we started comparing the energy that different fish use, so big fish, small fish, hot fish and cold fish, when we compared all those things together, this pattern just emerged from the data. which suggests that as fish get big, and particularly these warm-bodied ones, it's actually increasingly hard for them to lose their heat from their body. So they're producing a lot of heat, but as they get bigger, it's actually harder for them to lose that heat. So what this means is that big mesothems, theoretically,

should really want to avoid warm water. When you think about where these miso-femps tend to live, They tend to really only be found in reasonably cool water. We sometimes see them in tropical oceans, but that's pretty unusual. For the most part, they live cooler. What happens, though, if the oceans get warmer? What options do they have? Different fish do have different strategies that they might be able to lean on to lose heat.

So some of them can actually do wacky stuff with how blood moves around their body. A couple of the big tuna species seem to be able to do that. They can divert the way that blood travels around their body and maybe lose heat. heat that way. Another thing that a lot of species can do can just dive into deeper water. So in most oceans around the world, it's warmest near the surface, and then as you go deeper, it gets cooler. So what a lot of these animals already do is they dive down periodically, and we think there's maybe some kind of temperature regulation effect that underlies that behavior. But in the future, you know, and right now, like the oceans are warming pretty quickly. There is kind of a concern

Look, as the water increases, it means these animals are going to probably need a lot more food. And these large mesothemes also face this added issue of maybe overheating if they encounter waters that it's too warm. So they might just start moving to high latitudes. They might start swimming towards the North Pole in the Northern Hemisphere and in the Southern Hemisphere moving south. And we are already actually seeing that for a lot of species. Well, in fact, would that have on the ecosystem to have these, large predators moving into new environments. Unfortunately, their populations are really struggling.

So a lot of them have been overfished. But there are some mesothemic fishes that actually constitute a huge biomass in our ocean. Giant Atlantic bluefin tuna are a huge mesothem. Hundreds of pounds in body size. And there's an awful lot of them. They support massive globally important fisheries all across the Atlantic Ocean. And they're eating a lot of food. I've seen them feed in schools of fish, and it is like a feeding frenzy.

It's incredible how much food these animals eat. So they are playing a huge role in the entire Northeast Atlantic ecosystem. If they start to move, it could have potentially really important impacts on the whole ecosystem. What's it like for you to be out there on the water up close and personal with these giant warm-bodied animals? It's crazy. Honestly, it's life-changing. I mean, I've seen people cry, I've seen them scream, you know, with joy. You see them and it literally takes your breath away.

So I hope that we will still continue to be able to, you know, have the privilege of engaging and interacting with these kind of animals in the next few decades because, you know, there's something that we need to protect. Dr. Payne, thank you so much for your time. Pleasure, Bob. Nice talking to you. Dr. Nicholas Payne is a zoologist and associate professor at Trinity College Dublin in Ireland. Parrots are remarkable birds. Some have a gift for gab.

But they're also stunningly beautiful, with their vibrant, brightly colored feathers that make them highly sought after. Humans will go to great lengths to possess these birds, even in ancient times. And excavation of a 600-year-old burial chamber on the coast of Peru, uncovered parrot feathers sewn into a ceremonial headdress.

But those feathers came from a kind of bird that isn't normally found anywhere near the area. The discovery revealed an ancient parrot trading network, stretching from the Amazon to the Pacific coast. Live birds were transported across many hundreds of kilometers, through rainforests, across deserts, and even over the Andes Mountains, well before the rise of the Incan Empire. Dr. Izumi Shemada is one of the authors of this study. He's an anthropologist at Southern Illinois University in Carbondale, Illinois. Hello and welcome to Quirks and Quarks. Thank you.

To start off, tell me about the tomb in Peru where these feathers were found. What was it like? Well, the site is called Pachacamac, a very well-known archaeological site, just south of capital city of Lima, Peru. This site of Pachakamak became quite famous from the very beginning of Spanish colonial era,

Francisco Pizarro sent his younger brother to check this famous sight, primarily interested in the riches that could be found there. What happened then, unfortunately, the looting of graves begun, so that by the beginning of 20th century, there were literally hundreds of thousands of looters' pits, and it seemed like this famous site had been devastated by looters. So to find an intact tomb that contained intact funerary bundles was really quite a pleasant surprise.

Oh, so this tomb is intact, it hasn't been looted yet. Correct. Wow. Well, tell me about the headdress and the feathers. What was that like? Well, the culture known as Ichmas, they had a tradition of preparing the dead in a bundle by wrapping the body in multiple layers and then stuff in the offering inside.

And to finish the bundle, they placed the face mask and put the head ornament. Now, the head ornament included feather bundles, placed at the very top of the canonical funerary bundle. Wow. Well, tell me about the feathers. What kind of bird did they belong to? Well, the feathers, the moment we exposed them, literally struck us with its vibrant color, red, yellow, blue, and white. And by looking at the size and the vibrant color, we suspected these were not local birds. but rather Amazonian parrots. Wow. Now, you say these birds came from the Amazon,

but the burial site is in Peru, which is on the Pacific coast. Correct. How did you figure out that there was a trade network that got those birds from the Amazon to Peru? What we wanted to do was to determine using genetic markers via a specific taxonomical identity of these birds

and their geographical origins or provenance. So when you did the genetic studies, what did you find? Well, the DNA analysis made it very clear that indeed we were dealing with the validity of Amazonian parents or to put it more specifically, the variety of Macau. The DNA analysis also indicated that the Genetic variability is quite high exactly what you would expect from wild birds. Boy.

Now, it's a long way from the Amazon to Peru. So would these birds have been transported alive, or would they have been, just had the feathers transported across that distance? Yes, that was another question we had, was the form in which the feathers were transported. because we were wondering if the birds were transported live to the Pacific Coast, we actually tested their diet using a technique called stable isotope analysis. That gives us the composition of the diet. And not surprisingly, we found that these birds were eating a lot of food that's really,

which in certain type of carbon, carbon type 3, and high in nitrogen. They were eating food that was not the kind of food that you can eat in Amazonia. So what we felt was that these birds were actually being fed. Human created food for the birds. That is to say that these birds were live and kept long enough for the, their feathers and bones to show the food composition. Wow. Early pet food. Yes. They were fed along the way. That's a lot of work on the part of these people to get

these parrots across the continent. So if this trade route was transporting parrots and their feathers, what other kind of goods were crossing the mountains? Well, we have known archaeologists working in Peru has have known that at least by 3,000 BC, there were trades taking place connecting Amazonia and the Pacific coastal side. And things that were being traded were things like gold nuggets. Another is the aromatic trees.

Another one is the all kinds of, well, let's say the plants, psychoactive substance. And then last major item we have long suspected are the bird feathers. Wow. What does this tell you about the people who were running this trade route back then? I think as a whole it indicates that the human ingenuity, the persistence of the human that's, once they know what is it that available and what is it that they want, I think the people go a long way to acquire them. And oftentimes that they involve ingenious solutions. And I think that's what they tell us, that the people of diverse cultures that develop on the Pacific coastal side, they all desired these vibrant feathers, a way of building up your own,

prestige in power. Dr. Shimada, thank you as much for your time. You're welcome. Dr. Izumi Shimada is a distinguished professor of anthropology at Southern Illinois University in Carbondale, Illinois. Sometimes we get emails

asking if previous hosts of Quarks and Quarks have ever hosted a show together. Well, to celebrate 50 years of the show, we're re-airing a segment from 1995. David Suzuki, Jay Ingram, and myself took to the stage at the Glenn Gould studio in Toronto for a special 20th anniversary

show. We had a house band and an improv group that imagined what Quirks and Quarks might have sounded like if it had been launched hundreds or thousands of years earlier. There was a lot of laughter. And we had some special guests who helped tell our origin story. So this week, we're replaying an excerpt from that show. Hello, I'm David Suzuki. Hello, I'm I'm Jay Ingram. Hello, I'm Bob McDonald. From the Glenn Gold Studio in Toronto, welcome to the 20th anniversary special edition of Quarks and Quarx.

I don't think we sound a light. Do you think we sound alike? I don't think we sound alike. Do you think we sound alike? I don't know. He doesn't sound alike at all. The three tanners. Welcome, Jay and David.

Welcome back to the show. Back to your roots. And thank for joining us. Thank you. And welcome to our live audience here at the Glenn Gould studio, a full house. Thank you for coming. Now, the three of us came to Quercule.

and quarks from three very different areas. Now, for myself, I came from television, and I started in 1992. And actually, it was a very bizarre summer I had. I went on a summer vacation. And at the beginning of my trip, I was told that my television program, Wonderstruck, was canceled. Oh, boy. Then at the end of the trip, I found that Anita Gordon, who was producing the show at that time, was looking for a host for Quarks and Quarks.

So I guess I was in the right place at the right time, and I've been there ever since, and it's been a lot of fun. Now, Jay, you were the host for longer than anyone. Was it 12 years? Yes. And you've done the opposite, actually. You were in radio, and now you're in television on the Discovery Channel at Discovery. How did you come to Quirks and Quarks?

Well, I don't know if David actually remembers this, but I was a freelancer making something like $16,000 a year in 1979. Thought I was doing pretty well. I was walking down the halls in the old CBC radio building, and I ran into David, and David said to me, why don't you apply for the job of a host of Quarks and Quarks? And I can honestly say, up to that point, I hadn't even considered it seriously. So this man is responsible for those 12 lovely years as host of this program. That's great. I'll take credit for that.

It's true. Now, David, you were a geneticist. How did you go from that? I was a geneticist who used to push fruit flies. And I'm glad to say three people who did that won a Nobel Prize this year. So, see, you can go far pushing fruit flies. but I had been interested in broadcasting. I'd done some television in Vancouver,

and I was contacted by a producer in CBC named Diana Filer. And Diana really was the one that said, hey, I've got this idea for a science show. Would you be interested? And I was. Well, we've got Diana Filer on the line from Vancouver through the magic of our radio, and hopefully she can hear us.

Hi, Diana, are you there? Hi, yes, I am. Happy birthday, everybody. Hi, David. Well, Diana, is that how it happened? How did you come across David Suzuki and start the Quarks and Quarks Show? Well, actually, I started out with him in Vancouver, watching him on the television whenever he'd do a little science item in the 60s.

And when I got to Toronto, I've always wanted to do a science show. And I kept telling them, produce the executives that I wanted. A Suzuki-like host. But I went to a UBC alumni lunch in Toronto, because they said they were featuring Suzuki as a guest speaker. I thought, ha, here's my chance. So I went to hear him, and I almost didn't get past the crowd around him after lunch, but I thrust my card at him and asked him,

would he ever like to do a radio show? And if he did, I'd be delighted to talk to him. So that's how it started. And I was really disappointed in all those years that CBC had had myriad arts shows and nothing in science. And you know arts and sciences are supposed to be equal. Well, Diana, you managed to get the show going. I want to know where did you get the name?

I think we've got the best name of any radio program, quirks and quirks. Thank you. Where did you get that? Out of my head. I had a couple of names, and I kept thinking. There was a group of us that used to meet called The Poets Corner at a pub on Blure at Young, Fifth Avenue it was called. So the name came out of a bar? The name came out of a bar, and I kept shoving these names at my friends.

And the one that stuck in my mind that I had thought up earlier was, quirks and quarks. And I thought, well, they'll never go for it at CBC. So I thought up a very stayed mid-70s when that was science of the times. But it doesn't roll so trippingly off the tongue. I thought we also considered as it's going to happen. As it's going. Well, Diane, I have one other question for you. And it has to do with this. I want to see my name. I want to say my name too. Where did you come up with that? music. Well, you know why we got that music? Because it was free. You didn't have

to pay any royalties. A true CBC tradition. Yes, and it was electronic music and it was a disc I'd found in the record library and I sort of stashed it because I thought if I'm going to do a science show, I'm going to need some future sounding music. Now I remember, Diana, you gave me two different... I did. And you said

you can choose it and this is the one I chose. So I had a little input into that one. Yeah, you did, David. That's right. Well, it carried the show for 20 years and Diana, you were the person who created it. Thank you for joining us tonight. And that's Diana Filer from Vancouver, BC. Bye. That's an excerpt from our 20th anniversary show

that aired on October 28, 1995. I'm Bob McDonald, and you're listening to Quirks and Quarks on CBC Radio 1 and streaming live on the CBC News app. Just go to the local tab and press play wherever you are. Coming up later in the program, hacking our dreams to face up to our challenges. This is a really useful tool for dream science because it allows us to get information out from a dream

without somebody having to wake up. I am an actor, fresh out of theater school with big dreams and an even bigger drug habit. But things are pretty good. That is, until my best friend is set up on a date with David Lee Roth. Yeah, from Van Halen. If you know, you know. From CBC's personally, this is Discount Dave and the Fix.

The true-ish story about how a fake rock star led me to a real trial that held up a mirror to me. And okay, let's just say that not everyone in this story is who you think they are. Personally, Discount Dave and the Fix. Available now on CBC Listen or wherever you get your podcasts. Hello, Thing. Remember Thing from the Adams family? Mother and Father sent you to spy on me, didn't they? The disembodied hand that would run down hallways or watch over the family from the living room balcony?

Not above breaking a few fingers. But despite his lack of a brain, circulatory system, or even a stomach, Thing certainly seemed to be alive. Oh, thing. You poor naive appendage. Now, of course, that's fiction. If it happened in real life, the amputated hand would soon become dead tissue. And that makes sense, according to everything we think we know about how life works. which is why an incident in a marine biology lab at Memorial University in St. John's Newfoundland

was so puzzling for the scientists there. They were studying a type of sea cucumber when they noticed that a bit of tissue that had torn from it wasn't dying. After a while, it even seemed to be growing. That's when scientists realized they were looking at something never seen before that made them question what it means to be alive. Sarah Jobs, is a PhD candidate in marine biology at Memorial University, and she led the study. Hello, and welcome to our program. Hello, Bob. It's my pleasure to be here. Set the scene for me in your laboratory.

What happened with the C. C. C. C. C. C. C. C. C. C. C. Cucumber, Sola C. C. C. C. Cucumber, Solaucucucucucum, in Solis Fabricci in examining other studies and other curious things about it. And a collaborator of mine was actually the first to notice that when the sea cucumber was removed from the tank and there was torn tissue left in the tank, this tissue seemed to be okay for a day and then a week. And we thought, this is odd. I wonder how long it could actually survive. Wow. So torn tissue, what was it that came off the sea cucumber? It was the tube feet that hold it on to rocks or the side of the tank, and they're frequently damaged in its natural environment.

So these sea cucumbers can regrow the tube feet or tentacles if they're lost, but we thought that the tissues that were torn off would just die. Oh, so instead of talking about a hand from the Adams family, we're talking about feet from a sea cucumber. Yeah, exactly. So close, but... Now, I understand that after a while you referred to these... leftover feet as zombie tissues?

Yes. Well, throughout the course of this study, it led to a lot of discussions about what does it mean to actually be alive? And it kind of took us down a philosophical road at some points because we could tell that these tissues were not dead. They're not decaying. They're continuing to reform, restructure, and persist. But are they actually alive because they're not reproducing? So what did you do to figure out what was happening with this zombie? tissue. One of the things we wanted to know was whether or not they were regenerating, because obviously

when they were torn off from the sea cucumber, there was a wound opening. And so we studied, first off, whether or not different cycles of cellular proliferation and regeneration were occurring. And they were, which was the first sign that this was something really unusual. And from there, we wanted to know things like, how are these tissue pieces actually fueling their existence? So we studied whether or not they were absorbing nutrients from their environment. And they were. And we studied whether or not they were able to reorganize their tissues and things like, how were they preventing bacterial infection?

So we studied their immune system and found out that it was still active. So it was kind of one question just opened up another and another and we followed it as far as we could. Wow. Well, how are they able to get nutrients out of the water if they're just feet? That's a great. We were wondering, they don't have a mouth, they don't have a digestive system, what could possibly be happening. So amino acids or dissolved nutrients that are surrounding them in their natural environment are absorbed across their body wall, their tissues and metabolized internally.

Boy. Yeah. And their immune system, does it work the same way as it does in the whole body? Pretty similarly, actually. So the immune system of sea cucumbers, the immune cells are known as selomocytes. And these cells, we observed in the initial stages of healing, migrated from the internal portions of the tissue to the wound site. And they aided in removing degrading tissue, making sure that there was bacterial invasion into the tissue, and helped restructure actually the fundamental tissues that were there. How long did they live? So in our formal study, they lived over three years. So we watched them for three years, looked at all their different changes, and thought, at a certain point, we have to cut ourselves off and actually put this knowledge out there into the world.

But we didn't see any signs that they were decaying or that they wouldn't have survived well past that timeline. Three years? That's astounding. How long does a whole sea cucumber live? That is one of the more mystifying questions. in sea cucumber research, it's very hard to age them properly. We don't really have tools that can do this. And so some people believe that they could potentially be immortal or at least incredibly long-lived because of their regenerative capacity.

We don't know their defined timeline. So do you think if these zombie tissues are left long enough that they could regrow into a new sea cucumber? I mean, I can't say it's impossible. but we haven't seen any signs that that's actually occurring, which is another reason that I guess highlights the odd nature of these tissues because it seems that instead of trying to clone themselves or reform a whole new sea cucumber,

which is sometimes seen in other species, it seems that they are adapting to best survive in their new form. Okay, so they're just surviving. Yeah. Does that make them immortal then? I mean, as far as we can tell, they show all the signs of being immortal. There are further tests that we would love to do to confirm that they are cellularly immortal. But as of where we're standing right now, it seems that they are happy and functioning as immortal tissue zombies.

Zombie feet. What would be the evolutionary advantage for the C cucumber to have its amputated tissue continue to live on but not reproduce? truly from many different perspectives there is no obvious evolutionary advantage to this it kind of defies the boundaries or the laws that we put in place for the evolution of adaptive advantages so it's possible that it's a byproduct but I think it would be really interesting and helpful to confirm that nothing else is going on here well is there anything that we can take from this I mean how useful could these almost immortal zombie tissues be for biomedical research? Sea cucumbers are actually relatively close to mammals, humans, on the evolutionary tree of

life. So because they are still invertebrates, there are very different ethical implications. They would break down accessibility to research because people would have much more broad access to actually studying these tissues than they would with other human models. So it could potentially give people the opportunity to study how tissues work, how they respond to different things like disease challenge. And I think it would be a great advancement in this area. So what advantage would it be to be using these for biomedical research compared to the cell cultures that are used today? Cell cultures that are used today have to be maintained in very strict culture conditions. They have to be kept in sterile environments, supplemented with nutrients and often growth factors.

And these ones, you could just plop in a tank and leave alone, and they would be fine. Well, they could certainly give us some pointers in survivability and the cell repair. Anti-aging, things like that. Absolutely, anti-aging, and it challenges everything we know about tissue degradability. Because it's interesting when we talk about protecting the oceans. We usually go to things like, oh, save the whales or the belugas. Who would have thought that the humble sea cucumber that just lies there on the sea floor could give us so much? 100%. I think it really points to the value of studying the underrepresented species in the ocean because there truly is so much left to discover.

And when you let curiosity drive your research, you come up with some really interesting things. Ms. Jobsen, thank you so much for your time. Thank you for having me. Sarah Jobson is a PhD candidate in marine biology at Memorial University. Have you ever had a really weird dreamweaver train. Drive the dreamweaver, I believe dreams can make sense of my life. Have you ever had a really weird dream and wondered, what the heck was that all about? Well, the new study suggests that dreams are not as random or as meaning.

as they might appear to be. Researchers have found that what you dream about at night is highly influenced by what you think about during the day. Dr. Valentina Elche was lead author on this study. She's a neuroscientist at the University of Freiburg in Germany. Hello and welcome to our show. Hello, thank you. First of all, just generally, what influences our dreams?

We know from our studies, we have understood that there are many factors that influence. our dreams. For sure, the experiences that we have during the day can have a great impact on the content of our dreams. But we also notice that there are some individual factors that characterize each of us that can influence how frequently we can remember our dreams. Well, if our dreams are sort of reimagining what happened in our daily lives, why does the mind do that? There is an idea that dreams might help us to process the experience, is also the emotional charge that we have during the day.

Sometimes we might get to bed at the end of the day, very angry, and then we discover in the morning that we are a little bit less angry about what happened the day before. For sure, sleep helps in this processing of the memories and of their emotional charge, but scientists are stuck into think that dreams might also play a rule in this process. Indeed, when we dream of something that we have, during the day in physiological condition, we do not dream exactly what happened during the day.

We tend to have metaphorical and also hyper-associative experiences. Dreams, they might help us to understand what happened to us during the day. So you're saying the brain is kind of going through our daily experience and deciding what to keep and what to throw away, what to remember? Yeah, this is one of the hypotheses. While we are awake, our brain collects so much information, and for sure it cannot retain everything. Potentially, dreams might help us to learn from our experiences and retain information

that help us in our survival during the day. Well, take me through your study. How did you examine the influence of everyday lives on dreams? What we did was that we asked many people, ranging from 18 to 70 years of age, to record every day, right after the awakening for 15 days, everything that was going through their mind just before they woke up. During the day, they were asked again to record everything that was going through their mind. So in this way, we managed to collect recordings of people while they were asleep

and also while they were awake. How many of these reports did you end up with? We ended up with more than 4,000. Wow. It was a long job. We use AI to analyze the content of dreams. Basically, we asked several AIs to evaluate it. For example, we asked to evaluate how much on a scale from 1 to 9,

a dream was visual, positive or negative, and so on. So basically, we use this large language models to automatically analyze the content. Now, I understand that COVID played a particular role in this study. Tell me about that. Yeah. COVID impacted the content of dreams. During COVID, people tended to dream much more of being limited in their freedom that was either physical.

So, for example, dreaming of finding a road that you cannot go through or a door that you cannot open, but also metaphorically. For example, dreaming of wanting to do something but not doing it because you're considering it that's something not appropriate in this moment. moment. So the restrictions of the lockdown were creating dreams of, you know, anxiety in a way, or being trapped. Yeah, they were creating dreams of being trapped. And what was even more interesting is that during COVID, we tended also to have much less metaphorical and imaginative dreams. During COVID, people tended to dream much more of their daily lives exactly as it was. So, Again, it looked like dreams were affected by that. Dreams sometimes seem to be completely crazy.

I mean, nonsensical almost. Yeah, we noticed that. And we noticed also that the degree of how much dreams appear to be strange or bizarre might depend on our individual attitudes. For example, in our study, we have noticed that people who tend to mind wonder have more bizarre dreams, less coherent dreams, and more immersive dreams, meaning dreams that are more vivid, more visual, as compared to those who instead tend less to mind wander during the day. Oh, wow.

So daydreaming can affect your night dreaming. That's interesting. Yes, we are still in the process of understanding the relationship between the two things. Were there some dreams that are common that everyone has? such as, say, anxiety dreams? For sure, there are some groups that are studying the occurrence of topics in dreams that are shared across different people. They are called prototypical dreams.

And we are still trying to understand why so many different people also belonging to different cultures tend to have this shared topic. My interpretation is that each one of us might provide to these experiences different meaning for somebody. being back to high school could be something very stressful. For some other people, it said might be something very nice. Dreaming of these experiences might be a way of the brain to represent our concerns. Well, given that dreaming is reinterpreting the day's events in new ways,

can people use this to their advantage to try to better understand their own lives? Yes, for sure. It is something that becomes part of the individual sphere, meaning that, for example, there are some approaches. So from a psychological point of view with the psychotherapies that can help you to understand better the reason why you have dreamt of something. So for sure, looking at your own dreams can help to have some insight in your moods, in your current concerns. and so on. So for sure, getting a look at your own dreams help. I use the first example for me for my studies is always my dreams. Dr. Elche, thank you so much for your time. Thank you for inviting me. Dr. Valentina Elche is a cognitive neuroscientist. She led this study when she worked

with the IMT School for Advanced Studies in Italy. She's currently a postdoctoral fellow at the University of Freiburg in Germany. As Dr. Elche's study shows, what you think about during the day can show up in your dreams at night. But what if you're struggling with a decision? Should you sleep on it and let your subconscious mind work away at it? Throughout history, people have recorded solutions coming to them through their dreams, including some pretty significant scientific breakthroughs. For example, Canadian scientist Dr. Frederick Banting woke up in the middle of the night in October 1920 to jot down an idea of how to treat diabetes. Within a year, Banting and his colleagues had discovered insulin.

Now a new study as testing of dreaming can help people come up with solutions to creative puzzles via a process they call dream engineering. Dr. Karen Conkley is a cognitive neuroscientist at Cambridge University in the UK. Hello and welcome to our program. Hi, thanks so much for having me. First of all, what do you mean by the term dream engineering? So dream engineering is a suite of techniques that have been used for centuries, but scientists are really hopping on board to kind of move beyond the science of observing dreams

to manipulating them so that we can study why we dream and create interventions for when dreams so alive. So how do you manipulate dreams when people are asleep? Yes. In one sense, you could think that we're all already. engineering our dreams. How we spend the minutes before we go to sleep, that's the stage for what we dream about. So if you read a really good book or if you watch a scary movie or doomscroll or listen to a beautiful song, all those are already ways that you can engineer your dreams. There was actually

a recent study that if you're listening to an audiobook as you fall asleep, the content of that audio book is replayed in REM sleep and it influences your dreams. So you can do that consciously. you can specifically think of something that you would want to dream about as you're falling asleep and you're engineering your dream with dream incubation. But what a lot of my research focuses on is, yes, engineering dreams while people are asleep. So we use lucid dreaming, which is when you're aware that you're dreaming while remaining asleep. And lucid dreamers can actively control their dreams, make decisions about what's going to happen.

And we also use sensory simulation where we quietly present sound or lights or sometimes even smell to dreamers who are asleep that get incorporated into the dream and can influence dreams in a whole lot of different ways. Okay. So lucid dreaming, that's when you're having a really bizarre dream and you kind of go, this is a dream. This can't be real. So you're half awake, but not really. Yes. Have you had one? Oh, yes. Very often. This can't be right. There's something wrong here. This isn't right. That's awesome that you're a lucid dreamer. So how are you able to do that then? Take me through your study. Yeah.

So the way that we induce lucid dreams in the lab is first, honestly, we recruit people that are already good at lucid dreaming because it's pretty challenging to get a lucid dream in a laboratory. Even if you lose a dream often, like once a week, we need you to lose a dream while you're in the lab wired up to our equipment. We wire them up at night and let them sleep in the lab for, you know, six hours to get acclimated. And then around 4 a.m., we wake them up and we keep them awake for a little while. and this technique of waking somebody up is really good for lucid dreaming. And then they go back to sleep. And as they go back to sleep, we do a technique called targeted lucidity reactination. So in this technique, we repeatedly pair a sensory cue, such as a beeping noise or a flashing light,

with a prompt to become lucid, become consciously aware and mindful, first while you're awake. So we give them a prompt that says, as you notice the cue, you become a beautiful. And so we ask them to get into that mindset every time they see or hear this cue. And the association becomes automatized so that then when they enter REM sleep and we present the cue again, it gives them a much higher likelihood of having a lucid dream. Oh, now you mentioned REM sleep. That's when dreaming happens? So the most vivid narrative dreams that we have do usually occur during REM sleep.

But actually, there's not a one-to-one correspondence. Ah, so why do you need lucid? Drimming then? So lucid dreaming is a super helpful scientific tool. And one of the biggest reasons is because lucid dreamers can make decisions in their dreams. And so they can complete actions within their dreams that can be objectively measured and verified in real life. So we can tell a dreamer, if you're lucid, look left, right, left, right, twice with your eyes. And then we can see from electrodes next to their eyes that they're doing that, even though everything

else about their physiology says they're asleep. And so we've been communicating with dreamers using eye movements. We also have been asking them to sniff really rapidly and we'll measure that with a nasal cannula next to their nose. And they can also twitch their face from within the dream. You're paralyzed, but if you try to move your face a little bit, we can pick up twitches. And so this is a really useful tool for dream science because it allows us to get information out from a dream without somebody having to wake up. So in our recent study, what we did is we gave people brain teaser riddles before they went to sleep. One of the theories about why we dream, as you mentioned, is that dreams help with creative problem solving. But it's difficult to test if it's the dream itself that's

doing the work or if it's the incubation of thinking about that problem while you're awake and then the answer happens to come to you in a dream. So before sleep, we gave people these brain teaser riddles that were designed to kind of be solved by a stroke of insight. So, for example, how do you plant four trees exactly equidistant from one another? You can't plant them in a line because the farthest trees would be farther from another. And you can't plant them in a square because the trees of the diagonal would be farther than their trees adjacent. So how can you do it? So we gave people puzzles like this.

And while they were working on the puzzles, they were listening to random sounds. So they worked on puzzles until they failed to solve four. And then at 4 a.m. during the lucid dreaming portion of the experiment, we said, all right, now in your dreams, listen for any puzzle-related cues. And if you hear a puzzle view within your dream, continue working on that puzzle and only that puzzle within your dream. For instance, by asking the dream to work with you on the puzzle or dream character or entering the puzzle scenario in your dream, trying to walk into that forest and see those trees. And so kind of trying to have this. more direct dialogue with your subconscious dreaming mind to see if people could reach that answer in the dream. Oh, I see. So you've got a puzzle and then a particular sound that goes with that puzzle. While they're asleep, you play that sound so that they will be directed in their dream to solve it while they're dreaming. Yes. Okay. So what kind of results did you get? So what we found is that presenting the sound cues during sleep did indeed cause people to dream more about those puzzles. And,

And interestingly, people both had lucid dreams about the puzzles where they would be lucid, aware that they're dreaming, hear the cue, and then try to solve the puzzle. But even when people didn't have lucid dreams, they actually still often dreamt of the puzzle that we were queuing. And sometimes in ways that we're very close to what we had instructed them to do. So some people, even though they weren't aware that they were dreaming, would still ask a dream character to give them the answer to a puzzle that we had been queuing. Wow. We didn't find that people actually solved the puzzles while they were dreaming. That happened very rarely. It happened mostly at home, maybe afterwards.

But in the lab, they tended to just have these dreams that loosely incorporated the puzzle, or maybe they were working on the puzzle in the dream. But what we found the next day is that if somebody dreamt of a puzzle, they were more likely to solve it. So puzzles that weren't dreamt of were solved less than 20% of the time, and puzzles that were dreamt of it were solved more than 40% of it. the time. Boy, that's quite a difference. Yeah. By the way, how do you plant trees equidistant from each other? So the solution to that riddle, you plant three in a triangle and then one either in a pit or on a hill,

like a pyramid. Oh, I see. So it forms a tetrahedron shape. Yes, exactly. You have to do 3D thinking. That's crazy. Okay. Are there other applications for dream engineering? Definitely. Dreaming is impacted in almost every psychological disorder. For instance, if you're recovering from an addiction, having a drug use dream is really common, and it can leave people feeling like they have more cravings and it can possibly lead to relapse. And so using dream engineering intervention to help people deal with those dreams and work with them so that doesn't have that outcome could be super helpful. The dream engineering could help people reduce their nightmares or work with their nightmares at a different way.

my actual main motivation for dream engineering is to really clearly understand why we dream and what are the biological functions of dreaming. And it's been really difficult to know that because without being able to manipulate our variable of interest, we can't study its effects clearly. And so even though there's all these theories about why we dream, we dream to process negative emotions, we dream for creativity, we dream to help us prepare for the future. We dream that we organize our knowledge corpus, strength and memories. but there's no scientific consensus on which of those theories is actually true because without being able to manipulate a dream as it's ongoing, you can't isolate the impact of that dream. Dr. Conkally, thank you so much for your time.

Yeah, thank you so much for having me. Dr. Karen Conkali is a cognitive neuroscientist at Cambridge University in the UK. She led this study while she was with Northwestern University in Illinois. And that's it for Quirks and Quarks this week. If you'd like to get in touch with us, our email is quarks at cbc.ca.ca. Our web page is cbc.ca. Where you can check out our past episodes and find more information on the research we covered in the show. You can also follow our podcast, get us on SiriusXM, or download the CBC Listen app. It's free from the App Store or Google Play.

Quarks and Quarks is produced by Sonia Biting, Rosie Fernandez, Amanda Bukowitz, and Dan. Falk. Our senior producer is Hannah Hoag. I'm Bob McDonald. Thanks for listening. For more CBC podcasts, go to cBC.ca.ca slash podcasts.