From the Vault: Brain Soup and Liquid Brains

about it beyond that it's about liquid brains. Huh. Yeah, yeah, I mean it's it's there is kind of this um, you know, yucky horror vibe to our sort of selling of the concepts certainly, but it really gets into like what we can figure out via the liquefocation of brains um regarding like the nature of intelligence in an organic brain. This one was one that I was inspired to pick up after the twenty nineteen World Science Festival in New York. So yeah, so yeah, it's a pretty good one. Let's

jump right in. Welcome to Stuff to Blow Your Mind, a production of I Heart Radios has to ports. Hey, Welcome to Stuff to Blow your Mind. My name is Robert Lamb and I'm Joe McCormick. Joe, what what kind of image enters your head when I say the words brain soup? Brain soup? That's a Green Day song. Isn't it? Is it? I'm having trouble making soup. I don't know. I'm not I'm not I'm not not dukie, right, I only know like green Green Day songs. I think I'm

getting this wrong. H No. I also think of there's a horrible scene in Indiana Jones and the Temple of Doom where they're they're eating all kinds of weird foods that are parts of animals that you shouldn't eat, but why not. But one of those parts is they eat a monkey brain. I don't think that's supposed to be soup. By the way, one of my favorite things on the Internet is a total tangent is uh is franchise specific

WICKI entrees for inanimate objects. Allow me to explain, So, there is like an Indiana Jones wiki that's just a website out there. It's got entries on it for all the characters minor characters in Indiana Jones movies, all the adventures he went on. But then also they're just entries because it's a wiki of just objects that appear in

the Indiana Jones movies. So this will include like individual pages for each course of the meal in Indiana Jones and the Temple of Doom, and one of them, the one that's got all the snakes in it, is called

coiled Wrigley's. So it is it just it's just about a fictional food, or is it attempting to draw lines between these outrageous and you know, like shock oriented foods and in some actual traditions, because that if they're not doing it, that would actually be kind of a fun thing to do to sort of take the shock that they're that they're trying to to utilize in that scene and say, we'll hold on. Actually, here are some actual culinary traditions that are not really that shocking. Uh no,

it's not at all that informative mind opening. Just let me allow me to quote directly from the page for coiled Wriggles. Coiled Wriggles, also known as snakes Surprise, was a dish served at the Guardian of Tradition dinner given at Pancock Palace in n five As the second course. It was live baby eels stuffed inside a moist boa constrictor. One of the guests at the dinner, a merchant, was very pleased when the dish was served. Another guest enjoyed the eels with great gusto. I have not seen that

film in a very long time. I really don't know how it would hold up. Some elements certainly do not. You know, I should point out that, like you know, talking about brain soup, actual brain soup does exist. Do you have you know, various pork brain soups, etcetera. And even though I'm a I'm a pet scutarian these days, I wouldn't order pork brain soup at a restaurant. I looked at some photos and it looks perfectly delicious and

not at all weird. Uh So I just want to drive that home regarding the consumption of of brain based soups before I bring up, uh something that comes to my mind when I when I hear brain soup and what came into my mind when I heard it recently, I instantly think back to the film. It came from Hollywood. Oh, yes, so this was this is a film. It's it's I think you can watch most of it on YouTube these days.

But as Dan Ackroyd, John Candy Cheech and Chong Gilda Radner, that whole crew, and sort of before Mystery Science Theater, there was this movie it was just a clip show of like bad sci fi films and stuff, with the hosts of the movie making jokes about them. Yeah, and so a lot of trailer clips, a lot of weird clips. And there's a whole section that I that I loved

as a kid about brains. You know, all these weird fifties and sixties brain monster films, which which I think are probably expressing a certain amount of anxiety regarding like post war advances in neuroscience and the sort of existential conundrums that are raised. You know, like, am I just a brain? What does it mean to be just a brain? Well, a brain jump out of someone's ed and attacked me

with its tentacles. There was a lot of revolutionary neuroscience going on in the nineteen fifties, and yeah, I can see exactly why people would be concerned about this kind of thing, though some of them are just more like I think there's one called like the Brain from Planet Rouse or something that, yeah, just giant brains swarming at people.

So I don't know exactly how much that plays on anxieties about neurology, but I mean I get that what I really get a sense of it when I see clips from Fiend without a face because as we have the fabulous stop motion brains and kind of like spinal column tentacles people, yeah, all over the furniture. We just sprayed for brains last week. But anyway, this particular segment on brains was introduced by Dan ackroyd Uh and he's

he's he's in this this scene. It's like he's in a butcher's shop and he's playing a maniacal Perhaps he's supposed to be like a mad brain scientist, or a brain butcher, or like a brain addict cannibal. It's it's kind of hard to say, it's not entirely clear, but it's it's silly and it's gross, and it's I was tempted to play a clip from it here, but it's just so over the top that I don't I don't think it would translate well to an audio only environment.

You are correctly capturing here the strangeness of the premise for this sketch in the movie. I don't just blithely throw around the phrase cocaine fuel. But there there are some cases where you get you get a suspicion. But also in that scene, I remember Dan Ackroyd is doing a voice that sounds a lot like a Monty Python voice. It's he sounds like the leader of the Knights who say knee, Yes he does. It's that kind of like

ridiculous cartoonish voice. Uh yeah, the whole segment is is fabulous, all right, But all this sort of these sort of visceral reactions to the idea of brain soup. Aside, we are not going to be talking about eating brains today on the show. We're going to to talk about the very real practice, the scientific practice of making brain soup to better understand the neural power of animal brains. Well, I am very intrigued already now, Robert, I know this.

The subject is not coming out of nowhere. This is inspired by something that you just saw when you were at the World Science Festival in New York City last week. That's right, Yeah, I just got back and uh yeah. This is held every the last week of May every year, and as usual I got to hear some of the world's leading scientists and thinkers discussed a number of exciting topics, and one of the talks I attended was rethinking thinking

how intelligent are other animals? This is always a great subject and something we've revisited quite a few times on the podcast before. One time we talked with friends devol here on the podcast in an interview about his book. His book, I remember had a kind of awkward title. It was something it was something like, are we smart enough to know how smart animals are? Doesn't really roll off the tongue. But it's actually a really good book. Uh. And and this has come up with reference to the

intelligence of birds, and and quite a few cases. Actually, yeah, and so this particular talk was loaded with interesting participants, but the participant that got me thinking about brain soup was Susanna or Kolana Uzel, PhD, biologist and neuroscientists at Vanderbilt University in Nashville, Tennessee, where she is Associate professor in the Department of Psychology and Biological Sciences, and her

research focuses on what different brains are made off. Now, Robert, I envy you getting to see a panel that involved her, because I've actually watched a TED talk that she did back from I think it was twenty thirteen. She's she's a fantastic public speaker, So yeah, she seems like a

really good public science communicator. Yeah, Like when I say you know that you have a panel of of leading scientists there on the stage, like, don't don't imagine something stuffy, because you often have some just really wonderful science communicators up there that you know, are experts in their field, but are also able to talk about that in a way that people at you know, various levels of expertise can can jump in on. And that's certainly the case

with Susanna her Colono Ozel. Now I do want to mention you're probably you're hearing this last name. Sometimes you will hear people pronounce it her colono hose l um. If you're trying to look it up, it's h e r c u l a n O dash h o u z e l. Trying to to do the name justice here with our bungling mouths. So, as she tells it, her Colona Hoose was working as a science educator um in Rio de Janaro, Brazil, and uh and she kept running into an old myth that I'm sure many of

you have run into before as well. Now this is not when we use the word myth too. In the non derogatory sciences foundational story maybe involving supernatural elements. Yeah, this is the derogatory myth, and that myth is we only use ten percent of our brain. And this has been used really overused in I FI movies, especially over the years, as recently as Teens Lucy and twenty eleven is Limitless Um, which by the way, decided to double it, but still but still stuck to this idea that there's

only a small percentage of the human brain that is available. Uh. And of course, all these these films and pretty much anytime you see this trouted out, it's it's with the idea like there's there are ways to open up the rest of the brain. There's like this dormant brain. Uh, these dormant brain portions that can be utilized if only you have the key. And the key, of course is left of the cage, right, and it's supplied by you know,

some sort of mad science. If you're in a fiction or if you're encountering it saying some sort of self help scenario, then they're going to sell you the key or yeah, if you're encountering it, and uh, it's say nutritional supplement marketing. I mean, this is a big thing out there. Yeah, but we say it's a myth because and we'll break this down a little bit here, but but basically, there's nothing to these numbers. Now, we we

all use of our brains. Well, when you instart, when you start to look at the claim, it becomes less and less clear what it even means. What does it mean we only use ten percent of our brain at a time? Do we only use ten percent of it ever in our whole lives? Like what even counts as

quote using the brain in the first place. Yeah, I feel like we've talked about about neuroscience on the show enough, you know, and talking about various f m r I S studies and like what parts of the brain are lighting up, what parts of the brain, and what networks of the brain are associated with different thoughts and behaviors, etcetera. That it's it's clear that like there's there is definitely a lot of stuff in play, and that virtually and

then really everything is in play. Um I guess, I guess the confusion could be if you're looking at various images of fMRI I s and you're thinking, oh, well, that looks about like ten percent. That looks about like

ten percent. That's a really good point when people talk about f m r I studies, sometimes they will loosely and casually try to explain the findings of an fMRI I study by saying, hey, when somebody was doing this to ask with their brain, you know, they were trying to tie a knod or they were you know, whittling a whittling a horsey out of soap. When they're doing

this task, this part of their brain lights up. That's the phrase this lights up, which implies to the entire rest of the brain is dark until it just lights up, as if it's like totally dormant. And that's not true. I mean brain imaging studies like you know, PT scans and fm r I that they show relative activity, so that they're charting activity and seeing what areas, uh get get surges of activity relative to what they were doing at other times. Right there, the areas that are not

lit up are not lifeless. Right. But I mean, even back to this, I want to know again what what would actually mean to use your whole brain or to use certain percentages of your brain. I was reading around about this and I found one pretty interesting thing. So the neuroscientist Gabrielle and Torrey. I think she's at Boston

University now. She wrote an interesting post about this myth that I found on a website Knowing Neurons, and in one section of her article, she discusses difficulties determining what it would actually mean to use quote a hundred percent of your brain, Like, there's no single way to measure what portion of the brain is being used at any given time. The default mode network, of course, is in operation throughout the brain pretty much all the time. But

does that not count as the brain being used? I mean that even when you're at rest, the default mode network is whirring away all throughout the brain. Ye, quite unfortunately in some cases. In some case I don't know if you'd want to be without your default Well now I wouldn't want to give it up, but it it is kind of thorn in my side at times. It certainly can be. But then interesting, I really like this part.

So she tries to take this claim seriously, like this ten percent of the brain is being used claim, and she's like, what would that actually mean? Well, she offers one interpretation of what it would mean to use a dred percent of your brain, and it would mean a grand moll seizure, So it would be like limitless except Bradley Cooper takes a magic and it just makes his brain like like we almost explode. Yeah, exactly. So, to read from tories where quote, seizures are defined by excessive

and synchronous neural activity. If we wanted to use a hundred percent of our brains to stimulate each of the brains one hundred billion neurons, this is funny. We should come back to this in a second, to maximum capacity firing would result in a likely fatal physical experience. To hope for synchronous exit. Tory activity across the cortex is

in many ways synonymous to a Grand Mall seizure. Uh. This is the most severe type of seizure and leads to loss of consciousness and severe muscle contractions, not the unlocking of superhuman abilities. So I think obviously we don't just want universal synchronous patterns of excitation of every neuron in the cortex. That's stupid. That's not something to wish for, right. It's like, you don't want the brain working that hard universally.

It's like you don't want your your you don't want your xbox to be clearly just just heating up and that the fan is about to explode like that, you know, something's wrong with it. Yeah, my CPU is constantly And she also mentions the default mode network. You know, it's this diffuse, interconnected set of activity notes that show activation when the brain is otherwise at rest. You know, it shows the brain is pretty much never dormant. There's activity

throughout most of the brain most of the time. So where did this clearly false claim come from? The answer actually isn't known for sure, but I found one commonly cited early example is a quote falsely attributed to the American psychologist William James, the author of a great classic text, The Varieties of Religious Experience, which is still interesting to read parts of today. Yeah, we've cited him a few

different times on the show. Yeah, but apparently James did write something generically kind of like this, but without a number sited uh, in a piece called The Energies of Men, where you wrote, quote, we are making use of only a small part of our possible mental and physical resource

is which is a very different kind of statement, right. Yeah, he's not putting a fine number on it or saying like, you know, I mean that that statement alone is not not implying that the portions of the brain are inactive, just that, you know, we're not taking full advantage of our neurological potential. And I want to mention a bit

more about that in a second. Uh So, as to the origin of the phrase, the ten percent figure is also cited in the nineteen thirties, and this has been pointed out by quite a few investigators by the author of an introduction to Dale Carnegie's classic self help book How to Win Friends and Influence People, which possibly little known fact Charles Manson's favorite book Really Yeah, a classic of business leaders and serial killers alike. But this explains

it a bit though. Right We have here an introduction to a widely read popular book. Yeah, and the author of the introduction says, we only act, you know, we only use ten percent of our brains. The vast amount of our mental potential is untapped. And I mentioned this minute ago, but I just want to hammer home again. I feel like I've seen this nonsensical ten percent fact invoked by people selling some of the various like brain

booster pills and supposed new tropics supplements. Uh. I would advise people to be cautious about that kind of stuff. And I'm not ruling out the possibility that there are some nutritional supplements or drugs that might in some cases have a small effect on mental performance. But if somebody is trying to sell you pills that will unlock the untapped godlike potential of the you know, the paid access part of your brain, the brain is premium content. As

a general rule, be suspicious of this. I would I would advise in general, don't trust them and don't give them your money, because they're certainly tapping into something I think we all know to be true, and we all certainly want to be true, the idea that there is room for improvement exactly know that we can learn new things, that we can we can take on new patterns, and all of these things are true. You don't need a

phony number to back that up, exactly right. I mean, I think a large part of the basis for false fact about ten percent lies not in how much of our brains we use as a as a ratio, but in the way that we use our brains. And the most salient example that comes to my mind is the psychologist Daniel Konomon is really useful metaphors of system one

versus system to thinking. You know, so system one we've discussed on the podcast before, but system one is a suite of human brain functions that allow us to process information in a fast, easy, automatic, and approximate way. It's intuition, so you know, think rules of thumb, stereotypes, intuitive and

reactive thinking eyebawling it. Meanwhile, system two is described as the slow, deliberate, effortful thinking, the kind of reasoning you use when you make a list of pros and cons, or you solve a math problem, or you carefully plan a route of movement somewhere, or you effortfully trace out the logic of an argument. We're all capable of both kinds of thinking, but we also rely on systum tim one most of the time for most things. And that's

because of efficiency. Like you can't process all information in a slow, effortful way you don't have time. And system one is not all bad in some tasks. I think it might actually be superior. Like consider the way that overthinking some athletic tasks like shooting a basketball actually makes you worse at them, you know, like a lot of players find that they sink more baskets if they just try to relax and let the shot happen rather than

focusing on the distance and the angle and everything. And I think this actually even comes through in some more abstract tasks like sometimes I think people can be better writers if they if they just kind of enter a flow state and not sitting overthink over, deliberative lee about

the sentences they're constructing. This is very interesting and hopefully this won't be too much of a tangent here, but um, but it's also we have to be careful about thinking about like system one a system to being just complete like jackal and hides because actually the World's Science Festival, another Penelty attendant had to do with risky behavior and risk taking, especially in extreme sports UH such as say free solo climbing UH and like free cloaks of solo

climbing is a great example because you have you have certain individuals who definitely display more of a system to approach, like they are methodical. They're they're not they're not climbing at climbing that that that that that sheer cliff without the aid of ropes, you know, without having practiced it many times, without having climbed it many times with ropes and thinking through several moves ahead, you see where you're

going to go. On the other hand, you have individuals who do have more of an impulsive approach to risky behaviors, risk taking activities. But like with the basketball, you can say, well you can perhaps you're engaging in system too to practice so that you can reach the point where you can engage with the challenge with a system one mindset. I think that's exactly right. So, yeah, system one is not necessarily bad. It's not all bad. Sometimes it's bad.

And I think we're all aware of cases where we have used fast, intuitive, reactive, likely inaccurate thinking when we know that we probably could have and should have stopped to think things out slowly and deliberately. Like you can probably immediately think of examples where you really wish you had switched over to system to thinking, but you made a fast, intuitive decision and you came to regret it.

And I think it's this kind of frequently squandered mental potential that becomes the nugget of truth in the ten percent factoid. We use our whole brains, but we don't always use our brains as effectively as we know we're capable of in every scenario, because it's hard because we're in a hurry. Does that make sense? Absolutely? Yeah, We we we delive life. We have to engage both approaches to our decision. Make yeah. All right, On that note, we're

going to take a quick break. But when we come back, we're going to return to the idea of brain soup and to the work of Susanna or Colna Ozel. Alright, we're back. So we got sidetracked on the the idea of whether or not people actually use more than ten percent of their brains. We do in pretty much anyway you interpret that. But that came up because it was the basis of a journey of research that the neuroscientist

Susannah Orku Lana Zel went on. And so let's pick back up with her story from the event you saw in New York City. All right, So she was talking about another number that she kept coming across that she found curious, that she found suspicious, and that is the number one billion. Oh. Now, this just came up a minute ago when we were talking about an approximation. Now, I don't want to indict the author that cited and because it's a reasonable approximation. But well, yeah, and we'll

get into we'll get into that. But but yeah, she kept running across this idea that the human brain contains a hundred billion neurons and ten times as many glial cells. But the thing is unlike that ten percent of the brain thing. This was not merely the domain of pop culture or in science fiction. No, this figure freak was frequently cited by neuroscientists, by psychologists, and and sometimes applied as a as a comparison to the number of stars in the Milky Way. I imagine a number of you

have heard this one before. What a hundred billion stars in the Milky Way. Yeah, So the idea of being like, hey, you have a hundred a hundred billion eurons in your head. That's as many stars as there are in the Milky Way, which I mean, on one level, I think that's a useful metaphor because you're basically making the statement that, um, that that inner space is as complex and vast as

we take outer space to be. But on the other hand, when you start looking at those actual numbers, uh, there's some problems on both sides, because for starters, the hundred billion star estimate in the Milky Way is not a solid number. By some estimations, the Milky Way has the mass of a hundred billion solar masses, but other estimates, say four hundred billion or even seven hundred billion solar

masses is more accurate. Yeah, this is a fascinating question on its own because so it's difficult to know the number of stars in the mill Key Way galaxy because obviously we can't just count them, as you can't look up there and count them. The best we can do is estimate on the basis of the mass and luminosity of the galaxy as a whole. But this presents difficulties too because there are plenty of things in the galaxy other than stars. Right, the vast majority of the mass

of our galaxy is not even normal matter. It seems to be dark matter, which is still an unsolved mystery and astrophysics. And dark matter, of course, is this hypothetical stuff that we detect by measuring its mass, in other words, the gravitational effect it has on stuff around it, But it doesn't appear to interact with electromagnetic radiation like light, making it unlike any other ordinary matter that we know of. So at this point we don't know what that stuff is,

and that's most of the mass out there. And then past that, we know that a lot of the ordinary matter in the galaxy is not just stars. Some of it is uh like unincorporated debris, cosmic gas and dust, just hydrogen clouds out there. Of course that's not the majority of the luminous matter, but it's enough to complicate the problem of estimating star counts. And then on top of that, you've got ice and comets and planets and black holes and a supermassive black hole at the center

of the galaxy. And on top of that also stars are of dramatically different masses, so you have to figure out the right average stellar mass to divide by. So it's it's almost like this isn't a perfect metaphor, but I was trying to think of one. It's almost like catching an unknown species of fish and then weighing it and then trying to guess how many bones it has. You know, like you can't count them just from looking from the outside, uh. And the bones aren't all the

same size and weight. Uh. And there's a lot of other stuff in there too that's not bones. But so you can sort of estimate based on a number of likely assumptions, but you can't get an accurate count, which leads us back to the human brain. And this idea of this number that was thrown around again not non inscience fiction films, but in pure viewed papers and in in in textbooks as well. It was just out there and sort of the scientific zeitgeis the idea that there

were a hundred billion neurons in the human brain. And we didn't know where this number comes from, right, And so Susannah Rocolano Hozel she was wondering too, and so she she started looking into it, and she looked and looked, and she found no pre existing count, no scientific basis for the number at all. The number was just floating around in the scientific world. So the obvious solution is, well, somebody's got to to look it up. Somebody's got to

count these neurons. And so she set out to do just that via a novel tool that she developed in the lab in two thousand five, and that is turning brains into soup. The cification of the of of of the animal brain. Question, did she say, what the soup tastes like? No? I believe she said that the soup looked like unfiltered apple juice and apparently turned some of the students off of apple is perhaps forever it looks. I mean, I've seen it looks like murky swamp water. Yeah.

So I doubt that anybody tasted it, because this is sort of like priceless research material. But uh I don't know. Then again, you wonder if somebody got curious at some point. I don't know. She's she's a she's a pretty good she's a wonderful communicator, and she has a wonderful sense of humor. I imagine if somebody had tasted it, even accidentally, she would she would have mentioned it in one of the talks or or write ups or interviews that we looked at. You know what, I've got a guess as

to what it tastes like. I bet it tastes like chicken stock probably probably a good good guess, and well and perhaps from Mount hot but we'll get into that. Uh So, Basically, yeah, so she she set out to make brains into soup. Uh So, Basically she came across previous lab efforts from the nineteen seventies to turn the brain into soups to measure DNA concentrations um. And one of the keys here is that soup is a homogeneous solution.

So if you reduce something like like the brain that to soup, then you have a better ability to like get a sample of that soup, do account within that sample, and then apply that, you know, to the full volume of the soup. So anyway, she said, well, well I could use this method then, uh, to figure out how

many neurons during the brain. You know, liquefy cell membranes leave the nuclei intact, allowing them, allowing everyone to you know, to count the remaining nuclei in a small sample and then multiply the number by the overall volume to get the whole brain total of neurons. This is great. You can't do this with a galaxy, can you, Like, you can't just look at one section of a galaxy and say, okay, now multiply that by the total area of the galaxy.

Because galaxies are not homogeneous. You would have to turn it to soup first, which you cannot do or I mean not on our scale. Anyway, you would have to have godlike powers, and then you would destroy the universe. Maybe that's how the world ends. That's their shrewd Ragnarock scenario. As the god or god's asked the question, how many planets,

how many stars are kicking around this thing? Well, let's turn it to soup and find out exactly, Loki says, or you can't count the number of stars in the sky, and he's like, watch me, Well this sounds this is exactly the kind of gamble that that ancient gods would get into. You know, um, just a mere bet and everything for mortals is at stake, right, But anyway, or Colono was not interested in that. She's interested in the brain.

So the main challenge with souping the brain was souping it just enough to retain the cell nuclei, but without breaking any of that down. Initial souping experiments via essentially a detergent went too far and attempts to flash freeze them with wickid N liquid nitrogen and then blend them. Well, that just caused a cracked mess. And she says that there were like frozen pieces of brain all over the place.

I think if anyone was going to taste her brain soup, that was probably gonna be when it would have occurred. But Anyway, then she found a solution fixing the brain tissue with from all the eyed before the dissolving it. And the result, she says again, looks like unfiltered apple

juice and allows this kind of count to take place. Right, So, you can pull out a small sample, you know what the volume of that is compared to the entire volume of the sample, and then you count the number of neuron nuclei in the small sample and then multiply that by the total volume exactly. Okay, So I think I mentioned earlier there's a TED talk she did in where she shows off anyway. In the middle of this this TED talk, she shows off a vial of this brain

soup on the stage. It's a little glass jar of mouse brain souper. It might be plastic, I don't know. It's a jar of mouse brain soup. It looks like murky swamp water. It's kind of sort of like an off beige kind of color. One of the best things about this particular talk, though, is that when she shows off the jar, she doesn't go and pick it up

from a table or demonstration stand or something. She's just got it tucked into the back of her belt like a gun just pulls it out, and then when she's done showing it off, she just slips it right back in under the belt. I mean, I guess it must have been there all day. Well. You know, one of the things that she pointed out in the talk is that some when she started doing these experiments, some uh

people objected. They were like, what are you doing through these precious brains, as if she were wasting brains, as if she were essentially the dan ackroid character from it came from Hollywood just you know, massacuring brain material. But she pointed out that, you know, the aside from it being highly useful, as they will explore the rest of this episode, also they freeze it and so they can save it for later. She says, she has a whole database. The freezer is full of brain soup. I'm sure, all

properly labeled and dated. Yes, So what they did is, yeah, they apply to fluorescent stain to differentiate the neurons from other cells. And she started with rats and other rodents, eventually working up to human brains, and eventually she had a verified count not one billion neurons, but eighty six billion neurons. Though apparently this can be higher as high as say ninety one billion, for instance, but eighty six billion is the like the ballpark account. That's uh, well,

that that doesn't seem too far off. I mean, that seems within a rough order of magnitude level of reasonableness. Well it does, and it doesn't like you know, she points out that this may not may not sound like much of a difference to a lot of us. And I have to admit when I first heard it it, I didn't really register that it was that much different thundered billion verses six. It sounds like, all right, well,

we almost got it right. And uh, the thing is, you know, she says that ten billion neurons is really is not a small sum when it comes to neural change, and when we're talking about the evolution of of of brains, she says, the difference there is an entire baboon brain and chain. So so yeah, that's a lot of neural power we're talking about there, and to be off on that can you know, can have consequences as well, explore when we're talking about like what makes the human brain

seemingly special. Yeah, that that's interesting, I mean, and that's where it ties into her larger theory about what it is that special out human brains. So obviously, neuro anatomists and other scientists have long debated this question, what makes human brains unique? Why? Why are we the only ones with computers? You know? Why don't rabbits have computers and all that? Uh? And so what is the physical property that gives the human brain its power? Is its size?

I mean that clearly doesn't make any sense because sperm whales have brains there's something like, I think at least six or seven times larger than human brains, and yet they don't seem to be smarter than us. Likewise, the elephant brain is much bigger and exactly and we're not discounting the intelligence of whales and elephants, but but but clearly their their neural power is not on the same scale as as human power. And we have to ask the question why, right, so we're able to do things

that they're not able to do. And is that difference related to sheer size of the brain? Clearly not? Could it be? Another thing that's often put forward is the ratio of brain size to body size. Right? Uh, the the encephialization quotation that actually doesn't seem to quite cover it either. Right. So one of the things you pointed out here is that we'll just consider a couple of these neuron counts again, humans eighty six billion neurons, uh. And then we have something like like a rat two

hundred million neurons uh. On a goody, which is a South American like rather plump kind of critter, but it is a rodent eight hundred fifty seven million neurons. Al monkeys have a one thousand, four hundred sixty eight million neurons, while a cappy bara again a rodent one thousand, six hundred million neurons. Okay, so they're up into the billion range, but the difference here is still orders of magnitude of difference, right.

And in her argument is like when you compare like like sized rodents and primates the primate brains, uh, you know, maybe the same size, but there are more neurons in the more advanced primate brains. Right. So what seems to be going on here is that it's not so much that there's something really special about human brains, but there's something special about primate brains. Primate the brains of monkeys and apes, you know, the primate creatures like us, that

they have these densely packed neuron heavy cortex cortices. Yeah, and then it comes down to concentration of urons. And by the way, she also has found that birds have primate like concentrations in the forebrain, which lines up with the with their intelligence despite much smaller brains than other intelligent animals. Yeah, we mentioned this before, but this really comes through in the sometimes startling intelligence of birds like Corvid's and parrots. Yeah. You look at a parrot, like,

how big is it's brain? Right, It's like, you know, you you snack on nuts larger than this creature's brain, and yet it has this startling intelligence about the efficiently packed to the neuron crammed forebrain sort of like a primate. Yeah. Yeah. Meanwhile, whale brain, you could climb inside of it and it's

and it's it's it's not quite there. All right. On that note, we're gonna take a quick break, and when we come back, we're gonna or more of Susanna or colono Ozell's ideas about the human brain, how it is evolved and whine has so many neurons than all right, we're back, so more about brains, all right, So One of the big take aways from Susanna or Colono Ozell's work is that, of course a big brain doesn't necessarily mean high levels of cognition. Again, it's more about the

neuron concentration. Yeah, this is what we were just talking about with the fact that obviously, you know, like whales, elephants, all these have much bigger brains than us. But there's a lot that our brains seem able to do that those brains can't. So it's not just size. There does seem to be something special about the way that primate

brains are organized. And that's the thing, primate brains not not just human brains, Because that's something that Orcolano Ozel really drives home, is that the human brain is just a scaled up primate brain. There's nothing special about the human brain beyond that, nothing God touched or anything of the sort. She says that this is very much in

line with what Darwin thought and was criticized for. Darwin thought the human brain was just another primate brain, but those who came after him, they often took their evolution

with a hefty dose of human exceptionalism. Wanting to think about us is a special case that the rules of life don't apply to like they apply to every other animal on earth, right And likewise, Umsel says that she faced resistance to a results due to the fact that they didn't support this view of human brain exceptionalism versus the brains of other primates. Again, it's just a scaled

up a scaled up primate brain, right. So her idea, what she argues, is that what the human brain is, you start with the primate brain, which primate brains, like brains of monkeys and apes in general, are more crammed with neurons than other types of brains in the animal kingdom usually. And then you look at all the primates, and humans have by far the guest primate brain. And then because it's the biggest version of this densely packed

primate neuron housing center, we are the smartest. That's essentially what makes us the smartest. And we'll get into why this seems to be the case and why um the the argument that Susanna rocol Hosel makes for it as well. Uh, But before we do that, I want to I want to touch base in another area that she lines up with all of this, and that is the subject of longevity in warm blooded vertebrates anyway, um, because it seems to be the case that neurons are more important than

body size here as well. So in two thousand eighteen, research that was published in the Journal of Comparative Neurology UM Rocolno Mozel and co authors found that in primates, birds, and other warm blooded creatures, the number of neurons that you have in the core in the cortex of a species predicts about seventy five of all the variation in the longevity across species. Body size and metabolism the usual standard because usually that's what we think of, right. An

elephant lives a while it's big, whales oft a while big. Right, She says that this only predicts around tw of of of the cases of longevity. And here's another slice of enough human non exceptionalism. If you do the math, she says, this means that humans live about as long as you expect based on their neuron load. In this particular brain soup study examined more than seven hundred warm blooded animal species. I want to see a list of those soups flavors. Yes,

the sou menu is it's quite extensive. At her lap now, why is there a connection between neurons and the cerebral cortex and longevity. Well, she says more work is required to figure this out, but she does have some ideas, and here's what she said in a press release on the paper from quote. The data suggests the warm blooded species accumulate damages at the same rate as they age, But what curtails life are damages to the cerebral cortex,

not the rest of the body. The more cortical neurons you have, the longer you will still have enough to keep your body functional. The cortex is the part of your brain that is capable of making our behavior complex and flexible. Yes, but that extends well beyond cognition and doing mental math and logic reasoning. The cerebrial cortex also gives your body adaptability as it adjusts and learns how

to react to stresses and predicts them. That includes keeping your physiological functions running smoothly and making sure your heart rate, your respiratory rate, and your metabolism are on track with what you're doing and how you feel uh and with what you expect to happen next. And that apparently is a key factor that impacts longevity. Fascinating. Yeah, so I love how already just this this concept of of brain, not this concept of brain soup, but this tool of

making brain soup. It already you know, is turning certain things that uh we used to think we knew about brains and the human brain and how it's different from other animals and indeed how how other animals think, turning all of that on its head and us another way

of thinking about it. Yeah. So one thing that this would, obviously, I think, have somebody wondering about, is, Okay, if if humans are the upper end of the primate brain, you know, with your neuronal loads, you've got a lot of neurons in the human human brain, how did we get that way? Does it happened? Because again, we can't go with any mythic interpretation here, whether there's no ancient alien or gods scenario where where the this particular primate was was touched

and made special. No, we we need to look to something in the natural world, something that that that explains this or like rapid growth of the brain, and uh Erculano Uzel's hypothesis has to do with straightforward energy economy, the energy that different species are able to take into their bodies. Right. She says that she thinks it all comes down to the calories and mass via a very early technological development that our ancestors made, that being cooking. Now,

this is an interesting hypothesis. I like this. Yeah, we know, we've discussed the essential role that cooking played in human advancement before. How it externalized. Digestion allows you to uh, sort of to you know, heat up this pod or not even necessarily a pod, just you know, a pit with fire even and partially digest various organic matter before you give your own digestions, a digestive system a shot

at it. This makes it easier to digest you know a lot of foods that would be impossible or difficult to consume otherwise, either because of their chemical components, or maybe they're just tough they're hard to chew, or or or they can't be chewed and cooking can make them softer, and of course just speed up overall digestion. Yeah, it just gives your digestive system much more access to the

nutrients inside through a variety of means. Yeah. Because and this ties into neurons, because neurons require energy, a lot of energy actually, Yeah, and the more neurons you have and the more energy you require fire to charge them up. Like, your brain consumes energy at a rate that is not proportional to its size relative to the rest of your body. It is the the great energy hog of your body. Yeah, we're talking. Neurons require six kilo calories per billion neurons

per day, so um urkileno. Ozell points out that the human brain costs on average five kilo calories per day, so, in her words, not quite a whole hamburger. But but I mean, when you think about that in terms of food, the types of calories you can acquire in the wild, without grains, without access to easy meat and all that, that that's that's a tough requirement. Yeah, let's take a moment to just realize how how, how how amazing the

hamburger is. I mean, and just in terms of like how much uh, you know, protein and potential nutrition is just jammed into that thing. There's a lot of energy in the hamburger, like it or not. And we you know, we take for granted, you know what a robust chunk of energy that is. And if we had and if we had we didn't have the hamburger, and of course all the things that are comparable to the hamburger and

modern culinary tradition. And if we didn't have that to to eat, if we had to eat like our primate brethren did and still do without cooking and modern food. Uh. She points out that we'd have to spend nine point five hours every day eating so instead of so you're just eating like raw vegetable matter most all that you

like a lot of animals do in the world. If you, if you like, like we do, watch a lot of documentaries, you'll frequently encounter, uh, you know, some an animal or another of panda, and you're like, oh, all it does is eat because it has to. It has to eat all the time, you know, to maintain um uh, this this body and ultimately it's brain as well. But of course our brain again has tremendous energy requirements. It only makes up two percent of our body, but it requires

twenty five of the body's energy. So that five calorie burger is just part of a two thousand calorie per day diet. So kolona Ozel contends that without cooking, we'd be in the same state we'd evolved to one point five million years ago, we'd be small primates with essentially the brain power of a modern guerrilla, but with some stone tool making abilities. This is kind of encouraging as a as a hypothesis for people who love cooking kitchen culinary enthusiasts. You you may well be taking part in

the most crucially human of all activities. Yeah, and I believe that Michael Pollen has made a very very similar argument before in terms of like why we we we love cooking, and why even if we don't cook, we're drawn to the myriad cooking shows that are out there. You know, we want to watch somebody cook, We want to learn about about different culinaries, traditions, and even for my own part, I've never been much of a chef.

I am not much of a chef either, but I've been enjoying some of these various like meal box things recently and it's teaching me some of like the basics of cooking. And you know, I'll still curse at a tomato, but there's something fulfilling about going through all the instructions and in turning this sack of raw materials into a delicious meal. Well, Uh, tomatoes are tricky devils. That can be seriously, I there, they're at both ends of my

you know, food love and hate spectrum. Basically, my favorite food in the entire world is a really good ripe summer tomato, and my least favorite food in the entire world is like a mealy white winter tomato. It's the worst thing on earth. Yeah, it's there's It's kind of I feel a similar way with cantalope, Like, there are a lot of mediocre cantle loopes out there, and if you have one, you could easily turn your back on cantal loops forever. But when you have like a really

good cantlelope, there's nothing else that can beat it. Well, it's funny we talked about these extremes that agriculturally produced fruits and vegetables. Arcleanoz l points out in somewhere I was reading or one of her talks, I think where she says, you know, it's kind of funny that the inherent logic of of what she's showing here is even there in some of the diet trends where like what

do people do when they want to lose weight? Well, one popular thing is the raw food diet, because suddenly you're condemning yourself to a forging type existence without you know, without the calorie benefits of cooked food. Yeah, exactly, but but cook But cooking food is something we did develop again, and that was roughly one point five million years ago. Um. And this is the key technology, she says. It changed

what was possible energy wise for the evolving brain. Our brains got big in a hurry after this, and our food technology, of course, continued to evolve, most notably via the agricultural revolution. Definitely. I mean that the history of of of human civilization is the history of our manipulation of food really and our stockpiling of food, and then

our trade of food and our wars for food. So we are using research that makes use of the brain soup technique to discover the possibility to discover how important the invention of literal soup might have been. Yeah. I love the cyclical nature of this particular episode. We started with with the brain soup and we came back to brain soup. It's glorious, Okay. Introducing a new show segment,

Soup Facts, Soup Facts Facts with Joe McCornick. Here's something if you're ever trying to figure out how much to season your soup. You know, you don't want it to be too salty, of course, but you also don't want to underseason. And how much salt should go in a soup. The best way to figure that out is to get the soup to the temperature that you plan to serve it at, and then taste and see how much salt

it needs there. Because the amount of salt that we can taste when we taste something for seasoning varies drastically depending on what temperature the food is at. So you might you might taste it and it tastes like it needs more salt, or it already has enough salt at one temperature, but in a different temperature might taste totally different. Interesting, I hadn't thought about that. I will use that the next time. I'm I'm, I'm following instructions from a box

and have the mix soup all right. Another place I always mess up with salt is with with pasta. If I'm boiling pasta like I keep putting into little soup, like I'm so afraid of oversalting something. Well, then i'm i'm, and then my my wife will come in and say, oh, then you're supposed to be throwing like a whole fistful assault in there. Basically, it's a reasonable concern. I mean, you can if you under salt something, you can always add more. But if you over salt, you can't take

it out right. Well, you know, I think back to the cocktail scenario, like if I mix up, if I mess up a cocktail to the point where I can't fix it, um, then I've wasted like two drinks, you know. But if I do that with a super stew and I've ruined dinner, like I have to then go and get a pizza or something, and I've wasted all of these resources. And you know, the most heartbreaking thing you

can do is have to potentially throw food away. And I have, I have got I have over salted things in the past to that point, you know where it's just basically inedible. There was some recipe where I had to and this was like a box meal years ago when I was first figuring it out, and I had like a thing of salt and a thing of sugar, and the sugar went into one component salting the other flipped them which made like a pretty sweet cole slab that also just did whatever the other thing was was

just inedible. No, that's a sad story, all right, So I guess we're gonna leave it there. Uh again Susannah Roclinol wonderful science communicator. Uh look her up. She's all over the internet. You can find her ted talk readily easily, and they're also various interviews with her. And then of course the scientific papers are out there to look at as well. Uh. So also thanks to the World Science Festival um for letting me attend and uh and you know, taking in all of this data. Look at the World

Science Festival as well. Uh. They have a wonderful YouTube page. They'll put a lot of these talks up um, you know, over the course of the weeks and months ahead moving into next year. And in the meantime, if you want to check out more episodes of Stuff to Blow your Mind, head on over to Stuff to Blow your Mind dot com. That's the mother ship. That's where you'll find them all. And if you want to support our show, we commend

you for wanting to do so. The best thing you can do is to just rate and review us wherever you have the power to do so, wherever you give it, wherever you get this podcast, leave some stars and a nice review, and of course just tell people about it, about us, uh, tell your friends, tell your family, and then tell them how to find this show. Huge thanks

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