Speaker 1: Hey, welcome to Stuff to Blow Your Mind. My name
Speaker 1: is Robert Lamb and I'm Joe McCormick, and it's Saturday.
Speaker 1: Time for a vault episode, a classic episode of Stuff
Speaker 1: to Blow Your Mind. This is a part one of
Speaker 1: our exploration of the split brain experiments. This episode was
Speaker 1: originally published January. If you have not listened to these episodes,
Speaker 1: you've probably listened to episodes where we refer back to him,
Speaker 1: or even older episodes where we kind of laid the
Speaker 1: ground work for actually doing this exploration, because this is
Speaker 1: an important topic. You know, how does our brain work,
Speaker 1: What happens and what is revealed when there is a
Speaker 1: division in the brain when hemispheres are separated from each other.
Speaker 1: There's some groundbreaking experiments that we cover in these episodes. Yeah,
Speaker 1: this pair of episodes is one of my favorites, and
Speaker 1: we hope you enjoy it. The powers of Hide seem
Speaker 1: to have grown with the sickliness of Jackal, and certainly
Speaker 1: the hate that now divide did them was equal on
Speaker 1: each side. With Jekyll, it was a thing of vital instinct.
Speaker 1: He had now seen the full deformity of that creature
Speaker 1: that shared with him some of the phenomena of consciousness,
Speaker 1: and was co heir with him to death and beyond
Speaker 1: these links of community, which in themselves made the most
Speaker 1: poignant part of his distress. He thought of hide for
Speaker 1: all his energy of life, as of something not only
Speaker 1: hellish but inorganic. This was the shocking thing that the
Speaker 1: slime of the pit seemed to utter, cries and voices,
Speaker 1: that the amorphous dust gesticulated and sinned, that what was
Speaker 1: dead and had no shape should usurp the offices of life.
Speaker 1: Welcome to stuff to blow your mind from how Stuff
Speaker 1: works Dot Carl, Hey, you welcome to stuff to blow
Speaker 1: your mind. My name is Robert Lamb, and I'm Joe
Speaker 1: McCormick and Robert. Why are you reading Robert Lewis even Sanadas? Oh?
Speaker 1: Because that's from the strange case of Dr Jackal and
Speaker 1: Mr Hyde from eighteen eighty six, and it concerns the
Speaker 1: idea of there being two entities within the human skull,
Speaker 1: two entities within the mind, indeed, two minds within the brain.
Speaker 1: And I think this is an interesting place to start
Speaker 1: because while it presents a very erroneous vision of the
Speaker 1: lateralization of human brain function, it also uh it gets
Speaker 1: some of the same like hair standing up on the
Speaker 1: back of the neck that the actual research we're going
Speaker 1: to be talking about today does, at least for me.
Speaker 1: Oh yeah, I mean, Robert Louis Stevenson was a fabulous
Speaker 1: writer and he's he's one of those authors that you
Speaker 1: can read today and it holds up so well. Did
Speaker 1: they ever make a good Jekyl and Hyde movie. It's
Speaker 1: been a very long time since I've saw it, but
Speaker 1: there was an adaptation and may have been a TV
Speaker 1: adaptation with Michael Caine Michael Kine. Yeah, and I remember
Speaker 1: really loving that and being quite disturbed by it as
Speaker 1: a child. Now, I was thinking there had to be
Speaker 1: a Jekyl and Hyde with Tim Curry as Jacky and Hide.
Speaker 1: But I think maybe I'm confusing that with the Muppet
Speaker 1: Treasure Island where he's uh, you're thinking of the Muppet
Speaker 1: Jackal and high. He's long, John self man, that scene
Speaker 1: where he tramples Kermit to death is brutal. Well, yeah,
Speaker 1: so so we are. We are beginning with kind of
Speaker 1: an erroneous model. But but I think helpful and because
Speaker 1: it is often easy to think of the brain as
Speaker 1: the thing itself, right, we fall into this center our
Speaker 1: mode of of of of you know, the thinking of
Speaker 1: the brain body relationship as being a rider and its horse,
Speaker 1: when instead it is more this idea of a centaur.
Speaker 1: This this this one single entity, um, you know, and honestly,
Speaker 1: we see this reflected in so many real and fictional scenarios. Uh.
Speaker 1: Take for instance, the late physicist Stephen Hawking a brilliant
Speaker 1: brain within a body that was gradually paralyzed by motor
Speaker 1: neuron disease. Or just look to our dreams in which
Speaker 1: the inner world of the brain runs wild while the
Speaker 1: body goes on lockdown. Uh, you know, think of our imaginings,
Speaker 1: our inner thoughts versus our outer smile and then they're
Speaker 1: all those disembodied brains and science fiction right from Crying
Speaker 1: and his robot body and teenaging Ninja Turtles to the
Speaker 1: Brain that Wouldn't Die Cane and RoboCop to one of
Speaker 1: the best I know that's one of one of your
Speaker 1: favorites as well, greatest of all time Lovecraft, the Whisper
Speaker 1: and Darkness, and so many Doctor Who characters, is especially
Speaker 1: the Daleks brain guy from MST three K. We just
Speaker 1: keep keep coming up with these these visions of the
Speaker 1: brain as they just sort of the central human thought experience.
Speaker 1: You know, I never thought of this until now, but
Speaker 1: actually the brain guy from Mystery Science Theater is kind
Speaker 1: of a great illustration of Daniel Dennett's short story thought experiment,
Speaker 1: where am I I wonder if there was any connection there,
Speaker 1: so I gonna have to have to have to reach
Speaker 1: out to the MST guys on that. You know, there
Speaker 1: are those like plot lines where his brain gets separated
Speaker 1: from him as somewhere else. Um, of course, we know
Speaker 1: that things are not this simple. No brain is an island.
Speaker 1: It's affected by a host of outside influences, including all
Speaker 1: sorts of environmental nervous stimuli. And we're learning more and
Speaker 1: more about the role of our microbiome and various parasites
Speaker 1: in human cognition. But even if we're to to distrib
Speaker 1: away all of that, even we're actually to become a
Speaker 1: brain and a tank, you know, Kane's brain in RoboCop
Speaker 1: two or or any of these sci fi visions take
Speaker 1: out all that external stuff just the brain, we still
Speaker 1: have to contend with the fact that the brain, like
Speaker 1: a government, is composed of different houses. The brain consists
Speaker 1: of two cerebral hemispheres connected by the corpus colossum. Uh,
Speaker 1: each each hemisphere with many different modules, all of these
Speaker 1: acting in concert with each other, all of it interconnected. Yeah.
Speaker 1: One comparison I've seen in some of the neuroscience research
Speaker 1: we're looking at today is that the brain is often
Speaker 1: described as a computer, you know, or by the metaphor
Speaker 1: of a computer. You know. It's not that it is
Speaker 1: a computer, but that Yeah, there's the analogy that the
Speaker 1: brain is like a computer in the different parts of
Speaker 1: the brain, or maybe sort of like different programs that
Speaker 1: run on that computer. But at least to one researcher
Speaker 1: we were reading, I said, maybe it's more accurate to
Speaker 1: think of the brain not as a computer running different software,
Speaker 1: but as a vast network of computers that are each
Speaker 1: capable of operating independently, but most of the time operate
Speaker 1: in in tandem. It's right. This is an example where
Speaker 1: if you don't really have much of an understanding of
Speaker 1: how computer works, the the the idea of thinking of
Speaker 1: the human mind as a computer as technology is more harmful.
Speaker 1: But if you have, if you have a better understanding
Speaker 1: of how computer actually works, it could perhaps be a
Speaker 1: more helpful metaphor Cuttle cat cuttle fish to the second
Speaker 1: oil Age Kingdom with or darkness. I don't dispute the eurostata,
Speaker 1: but if he's down here, we know not blood but darkness,
Speaker 1: the earth's black riches. No I could taste it on
Speaker 1: my lips. Today, I want to talk to you about
Speaker 1: the science of transgenesis terms genesist show. Now. I wanted
Speaker 1: to to I thoink it would be helpful to just
Speaker 1: go ahead and consider one particular question right up top now.
Speaker 1: And we've certainly received questions like this following episodes in
Speaker 1: which brain hemispheres are discussed, such as our discussions on
Speaker 1: the bicameral mind hypothesis or the alphabet in the Goddess.
Speaker 1: Because there's this kind of pop understanding, right that each
Speaker 1: side of our brain controlled certain aspects of being, and
Speaker 1: that certain individuals have certain leanings that you know you
Speaker 1: have right brain people, left brain people, and that when
Speaker 1: that we can reconnect with our less favored hemisphere. Now,
Speaker 1: there certainly are some pieces of evidence that we're gonna
Speaker 1: look at in this episode that certain functions of human
Speaker 1: life are strongly lateralized in one half of the brain
Speaker 1: or the other, but they're not necessarily these functions or
Speaker 1: personality traits that are understood in popular consciousness, like logic
Speaker 1: and creativity, right like taking or that you're gonna take
Speaker 1: some sort of a quiz online and find out if
Speaker 1: you're a right or lefty in terms of your brain. Now,
Speaker 1: a lot of these ideas apparently were popularized by nineteen
Speaker 1: seventy nine book titled Drawing on the Right Side of
Speaker 1: the Brain by Betty Edwards uh and and the downstream
Speaker 1: myth that kind of you know, took over a popular
Speaker 1: culture for a little bit. There is that, yeah, you
Speaker 1: had left side logic, right side creativity, And even in
Speaker 1: people who know better people, we still talk like this.
Speaker 1: I've noticed that I use this metaphor even though I
Speaker 1: know it's wrong. Like I will sometimes think of people
Speaker 1: as being very right brained or very left brained, even
Speaker 1: though that I know that that I've read before about
Speaker 1: how that's not correct. Well, likewise, if I hear it
Speaker 1: mentioned sanny yoga class, I'm going to be less inclined.
Speaker 1: I'm not going to be the jerk in the yoga
Speaker 1: class that like perks up and says, actually there's some
Speaker 1: interesting you know, I'm gonna set back and enjoy the
Speaker 1: class because because it's one of those things that can
Speaker 1: can feel true, right. But the idea goes back further
Speaker 1: than this particular book. I mean, it goes back to
Speaker 1: some of the earlier discoveries that we're going to discuss
Speaker 1: here about hemispheric division. Um. You know, the ideas of
Speaker 1: neurologist Paul Broca who lived eighteen four through eighty French
Speaker 1: neurologist or Carl Vernica who lived who live eighteen forty
Speaker 1: eight through nineteen o five, a German. They studied patients
Speaker 1: who had communication troubles due to brain injury um, such
Speaker 1: as you know, left temporal lobe injuries, and they figured
Speaker 1: that this was the language center. Thus language was left
Speaker 1: hemisphere focus. And this is one thing that actually has
Speaker 1: been more born out by good research in in the
Speaker 1: history of neuroscience, is that one thing it's very clear
Speaker 1: the left hemisphere of the brain does, is it is
Speaker 1: dominant in language function. Yes, it's not that the right
Speaker 1: brain can't do any language, but it can't do a
Speaker 1: whole lot of language certainly can't do what the left
Speaker 1: hemisphere do. Right. Uh, now, we we kicked off the
Speaker 1: episode with reading from Robert Louis Stevenson against Scottish author.
Speaker 1: He lived eighteen fifty eight. And according to neuroscientist Elizabeth Waters,
Speaker 1: who's put together some you know, wonderful ted talks and
Speaker 1: ted ed videos about this, uh this, this, uh this topic,
Speaker 1: she points out that Robert Lewis Stevenson, in his book
Speaker 1: Strange Case of Dr Checkl and Mr Hyde, presented the
Speaker 1: notion of a logical left hemisphere that is in combat
Speaker 1: in you know, in in in in this uh this
Speaker 1: struggle with an emotional right hemisphere, and uh it's It's
Speaker 1: also worth noting that Robert Lewis Stevenson was also inspired
Speaker 1: by two popular French cases of individuals who exhibited dual personalities,
Speaker 1: uh their name. They were credited as being uh Felida
Speaker 1: X and Sergeant Fay. And these were apparently cases that
Speaker 1: were really you know, well covered in French and British
Speaker 1: press at the time. You know, it's kind of popular
Speaker 1: science influencing, uh, popular science fiction. Do you have any
Speaker 1: sense of whether what was presented to the public about
Speaker 1: these cases was largely accurate or was mis leading? I don't,
Speaker 1: but I'd love to go back and look at it,
Speaker 1: because if you know, this is a case where you
Speaker 1: can the science influences the science fiction, and the science
Speaker 1: fiction influences, uh to a certain extent, how the public
Speaker 1: thinks about a given topic. Now, other another influence on
Speaker 1: Robert Louis Stevenson. Apparently he had a just a terribly
Speaker 1: high fever uh at one point during which he claimed
Speaker 1: to have experienced a split into which he experienced quote
Speaker 1: myself and quote that other fellow. Yeah, so this apparently
Speaker 1: had a big influence on him. An according to biograph
Speaker 1: for Claire Harmon, author of Myself and the Other Fellow,
Speaker 1: duality and the idea of the double self turn up
Speaker 1: again and again in Robert Louis Stevenson's work. Well, maybe
Speaker 1: I'm over interpreting here, and this could be just kind
Speaker 1: of a mundane parallel, but I mean I see stuff
Speaker 1: like that even in Treasure Island, you know, his adventure
Speaker 1: where long John Silver is at the same time a
Speaker 1: a pay sand and sort of good father figure and
Speaker 1: also an evil pirate. Yeah. Yeah, this is the the
Speaker 1: argument here, is, yeah, that this is the type of
Speaker 1: duality that that he was obsessed with, and and so
Speaker 1: much of it, so many of his works, I mean,
Speaker 1: essentially had a fever induced psychedelic experience and then this
Speaker 1: lining up with various elements of his of his life.
Speaker 1: I mean, that is the meat he chewed upon. But
Speaker 1: of course, this popular understanding of the left right division,
Speaker 1: you know that like the side ruled by passion and
Speaker 1: the right brain and the side ruled by logic and
Speaker 1: reason and the left brain. That's not exactly right, right,
Speaker 1: you know, as we'll explore, doctors actually looked to patients
Speaker 1: with missing brain hemispheres or separated hemispheres, and as appealing
Speaker 1: as this notion, maybe it didn't really hold up. I mean,
Speaker 1: they were all still logical and creative beings. You didn't
Speaker 1: just end up with us, you know, a Spock or
Speaker 1: whatever the opposite of Spock would be in the Star
Speaker 1: Trip universe. To be clear, though, Yeah, the brain is
Speaker 1: divided into two hemispheres and internal regions like the striatum,
Speaker 1: the hypothalamus, the thalamus, and the brainstem. They're also organized
Speaker 1: with left and right sides as well, despite appearing to
Speaker 1: be continuous when you when you sort of look at
Speaker 1: illustrations of them. Yeah, and for the rest of the
Speaker 1: this episode, in fact, this is gonna be the first
Speaker 1: of two episodes we're going to be looking at ways
Speaker 1: that despite this uh, this like emotional versus logical split
Speaker 1: being wrong, there are very interesting ways that the brain
Speaker 1: hemispheres are different and do different things. In fact, well,
Speaker 1: we can start with the mundane ones I guess right,
Speaker 1: like mundane motor control differences. Exactly, we can look to
Speaker 1: the two arms and legs. For instance, the right hemisphere
Speaker 1: of the brain controls the left arm and leg, the
Speaker 1: left hemisphere controls the right armand leg. Now I have
Speaker 1: read that in a way like both hemispheres can in
Speaker 1: some way to some degree control both arms. But that
Speaker 1: when he gets done to like fine motor control of
Speaker 1: like controlling the actions of the hand especially, that's where
Speaker 1: he gets really lateralized and like it's really going to
Speaker 1: be your right rain that's controlling what your left hand
Speaker 1: does with its fingers. Now, a more complex example is
Speaker 1: in but one that's extremely important is each eye has
Speaker 1: a left and right visual field, with the left visual
Speaker 1: field sent to the right hemisphere and the right field
Speaker 1: sent to the left hemisphere. Now, this can also be
Speaker 1: misunderstood because I've seen it represented in the press in
Speaker 1: places that where like the left eye goes to the
Speaker 1: right hemisphere and the right eye goes to the left hemisphere.
Speaker 1: And that's not quite right either, because both hemispheres can
Speaker 1: get some information from both eyes. But it has to
Speaker 1: do with the side of the visual field that you're
Speaker 1: talking a right, So like stuff that you perceive over
Speaker 1: to the left part of what you're looking at that
Speaker 1: goes to the right hemisphere, and stuff you perceive over
Speaker 1: in the right area of what you're looking at to
Speaker 1: the right of your center of vision that goes to
Speaker 1: the left hemisphere. And then our visual experience of reality
Speaker 1: it comes together from these two feeds. Movement and vision
Speaker 1: depend in on this uni hemispheric relationship. Now, why do
Speaker 1: our brains work this way? Yeah? Why the crossover? Why
Speaker 1: don't you just go straight up parallel? It's one of
Speaker 1: those things about the humanivice. It seems needlessly complicated, right um,
Speaker 1: And the thing is we're not entirely sure. One theory
Speaker 1: that has been discussed is that animals developed more as
Speaker 1: as animals developed more advanced nervous systems, there was an
Speaker 1: advantage in escaping to the right if something came at
Speaker 1: you from the left. So these are examples where we
Speaker 1: can actually look to specific hemispheres and say here, here
Speaker 1: here's where they're most active. But we can't easily extend
Speaker 1: this idea to other aspects of cognition, and certainly not
Speaker 1: to the overall human experience or things like pure logical
Speaker 1: thinking or creativity. No, not that. But there are some
Speaker 1: cognitive functions that do appear to be pretty strongly lateralized
Speaker 1: in one way or another, and one of them, obviously
Speaker 1: is language. We mentioned this, Yeah, that's localized to the left,
Speaker 1: especially complex language and the power of speech. There's some
Speaker 1: research indicating that like the right brain might be able
Speaker 1: to have a sort of simple lexicon or understand very
Speaker 1: simple bits of language, but if you want to generate
Speaker 1: a sentence like speak one out loud, or understand complex
Speaker 1: instructions in language, this is usually going to be dominated
Speaker 1: by processes in the left hemisphere. And we should also
Speaker 1: say that everything we say about hemisphere is in this
Speaker 1: episode is going to be for most cases. There there
Speaker 1: cases where this is reversed, where people have like the
Speaker 1: switching of which hemisphere is dominant, but we're talking about
Speaker 1: the majority of cases here right now. Meanwhile, attention, we
Speaker 1: see that more localized to the right hemisphere. Yeah, and
Speaker 1: this would be especially things like visual and spatial reasoning,
Speaker 1: like the right hemisphere is going to be very important
Speaker 1: if you need to imagine a map in order to
Speaker 1: give directions. So brain activity unbalancing, where one one side
Speaker 1: is more active in a given task than another. This
Speaker 1: this occurs based on which system is being employed in
Speaker 1: a given task, rather than anything about an individual or
Speaker 1: their background of This is all, of course, assuming a
Speaker 1: healthy brain. Obviously, if one side of your brain is missing,
Speaker 1: there's going to be more activity beside it's there. Now,
Speaker 1: no evidence suggests that individual individuals have truly dominant sides
Speaker 1: of the brain when it comes to their you know,
Speaker 1: their personality makeup, right, You're not like creative right brained
Speaker 1: or logical left brain right And likewise that the logic
Speaker 1: and creativity split idea. Uh you know again, you'll have
Speaker 1: individuals that are certainly more logical perhaps or more creative.
Speaker 1: But as as neuroscigned, as Elizabeth Waters has pointed out
Speaker 1: among many others, logic and creativity are not these two
Speaker 1: distinct notions. You know, they're deeply interlinks. Yeah, Like being
Speaker 1: good at logic is in many cases being a certain
Speaker 1: type of creative. Yeah, I mean, what you might dismiss
Speaker 1: is just a really logical exercise, like safe solving a
Speaker 1: complex math problem that may well require that will require
Speaker 1: some creative thinking. Likewise, a creative endeavor like say, writing
Speaker 1: a poem, finishing a novel, coming up with a cool joke, whatever,
Speaker 1: you know, those are gonna going to be activities that
Speaker 1: also involve logic. In fact, some of what we're going
Speaker 1: to discuss in this pair of episodes in in the
Speaker 1: neuroscience research turns this whole thing on its head in
Speaker 1: a way, because the left part of the brain that's
Speaker 1: more dominant in exercises involving speech and language often tends
Speaker 1: to be the more creative one in explaining behaviors. Right
Speaker 1: it's the one that tends to interpret and come up
Speaker 1: with explanations for things, as will as well talk about
Speaker 1: later on, which is a creative exercise, whereas the right
Speaker 1: brain tends to more often be the part of the
Speaker 1: brain that records experiences accurately without creating explanations for them exactly.
Speaker 1: And but but certainly, if I'm gonna, you know, drive
Speaker 1: home anything, we want to point out that that the
Speaker 1: creativity logic anything that employs these these two loose idea,
Speaker 1: you know, buckets of of of cognition. You know, these
Speaker 1: are going to be products of whole brain cognition like
Speaker 1: our our the brain is all these areas of the
Speaker 1: brain are working together, uh to create this effect. Now,
Speaker 1: ultimately in this episode we're going to be asking what
Speaker 1: happens when you cut those two hemispheres of the brain apart. Yes,
Speaker 1: but I guess we'll have to get to that after
Speaker 1: a break. Than alright, we're back now. Before we get
Speaker 1: to the idea of severing the brain hemispheres, we should
Speaker 1: probably talk about a little more about Broca and Vernica. Yeah,
Speaker 1: these are just two really key individuals to this whole
Speaker 1: discussion and even just the idea of understanding the human brain.
Speaker 1: Um So Paul Broca will start with him again eighteen
Speaker 1: eighty He was a French surgeon, neurologist and anthropologists. And
Speaker 1: he is also for anyone who hasn't read the book
Speaker 1: but has seen the title, he is the namesake for
Speaker 1: Carl Sagan's book Broke His Brain. Sagan describes at one
Speaker 1: point point holding a jar are containing the noted scientist's
Speaker 1: brain weight like imagining doing this literally doing literally doing it? Okay,
Speaker 1: holding holding the jar that contains his brain, and then
Speaker 1: thinking about like what you know, talking He talks a
Speaker 1: bit about Broca and and and you know, his his work,
Speaker 1: his personality, but also just sort of meditates on what
Speaker 1: you're doing when you when you hold this brain in
Speaker 1: your hands. I want to imagine that, having not read
Speaker 1: this book, it is in fact just like a caper story,
Speaker 1: with Broker's brain as the MacGuffin, and it gets traded
Speaker 1: around and their car chases, Sagan's trying to get it
Speaker 1: back from the KGB spies. Uh no, not quite, but
Speaker 1: Dante Skull shows up as well. Oh nice, so broken.
Speaker 1: Though he made important contributions to our understanding of cancer,
Speaker 1: the treatment of aneurysms and aphasia and his Sagan pointed out,
Speaker 1: Broca was also quite concerned with the medical care of
Speaker 1: the poor. He was you know, he was. He was
Speaker 1: a free thinker. He was a strong darwin supporter, and
Speaker 1: above just about everything, he was the founder of modern
Speaker 1: brain surgery. And Broco was influential in identifying regions of
Speaker 1: the brain as being especially responsible for certain cognitive functions. Right. Yeah,
Speaker 1: he investigated the rheinan cephalon the smell brain. But his
Speaker 1: name actually goes to a small region in the left
Speaker 1: frontal lobe of the cerebral cortex what we call Broca's area. UH.
Speaker 1: This is left hemisphere, third frontal convolution. To be specific,
Speaker 1: this is the area where articulate speech is largely localized
Speaker 1: and controlled. And his Segan pointed out given the importance
Speaker 1: of language and articulate speech and human evolution, this portion
Speaker 1: of the human brain may be considered, in Sagan's words,
Speaker 1: the seat of our humanity and some respects. And it's
Speaker 1: also something anatomists have looked for in the remains of
Speaker 1: our hominid ancestors, such as Homo habilists. Columbia University anthropologist
Speaker 1: Ralph Holloway Sagan sided us you know, studied and claimed
Speaker 1: to have found evidence for its development of a Broca's
Speaker 1: area some two million years ago, and this would have
Speaker 1: been around the time early tool use was beginning. UH.
Speaker 1: Also South African paleol anthropologist Philip Tobias also made this claim,
Speaker 1: though according to Suzanne Kemer, associate professor of Linguistics at
Speaker 1: Rice University, quote, these claims have been controversial. Many see
Speaker 1: no regular impressions that could be ascribed to brain structure here,
Speaker 1: and I can imagine it's probably difficult to just look
Speaker 1: at skulls and figure out what brain regions were evolved when. Right,
Speaker 1: but Broke A's a discovery here, broke his namesake. Here
Speaker 1: is the first of many discoveries that illuminated hemispheric separation
Speaker 1: of function in the brain. And you know, and really
Speaker 1: driving home the idea of the specific brain functions might
Speaker 1: be isolated to specific parts of the brain. Yeah, if
Speaker 1: there's a certain part in the left hemisphere that seems
Speaker 1: especially important for language, what else could be lateralized? Right now?
Speaker 1: Just to throw in the nowadays, you hear more talk
Speaker 1: of networks as opposed to regions again, getting in this
Speaker 1: idea that that that that we're looking at at a
Speaker 1: network of of of different systems and not individual areas
Speaker 1: that are just doing all the heavy lifting. Yeah, your
Speaker 1: brain is less like a computer maybe in more like
Speaker 1: the internet, right, but a conscious internet. That's scary. Uh
Speaker 1: so horror movie pitch the conscious Internet. Uh yeah, and
Speaker 1: then it takes physical form via three D printers. Right,
Speaker 1: But let's also talk about about the German Carl Vernica
Speaker 1: okay live eight five a German. Yeah, both thus the Vernica,
Speaker 1: uh he was he has another area of the brain
Speaker 1: that's name for him, the vernica area, and he first
Speaker 1: described this area in eighteen seventy four, and it's found
Speaker 1: in the posterior third of the upper temporal convolution of
Speaker 1: the left hemisphere of the brain. It's close to the
Speaker 1: auditory cortex and seems to play a unique role in
Speaker 1: the comprehension of sound and language reception and comprehension. So
Speaker 1: the stage is set to discuss the lateralization of certain
Speaker 1: brain functions. But we mentioned earlier that this episode was
Speaker 1: really gonna end up focusing on cutting brains in half.
Speaker 1: And I know you're out there saying, when are you
Speaker 1: going to cut the brain in half? Robert, I think
Speaker 1: it's time. We've got to make the incision. That's right,
Speaker 1: And what better time to just slice the human brain
Speaker 1: in half than the nineteen sixties and seventies. It's really perfect.
Speaker 1: I mean, you could really almost it's tempting to just
Speaker 1: want to think like a left brain, rightlin brain, old
Speaker 1: fashioned idea and have like the nineteen sixties hemisphere, in
Speaker 1: the nineteen seventies hemisphere. Right, there's just something something perfect
Speaker 1: about the post revolutionary hemisphere. Uh no, No, So we're
Speaker 1: gonna be talking about the research of neuroscientists named Roger
Speaker 1: Sperry and Michael Gazzaniga. And so actually the brain cutting
Speaker 1: started in the nineteen forties, but it was in the
Speaker 1: nineteen sixties that the research on people with severed hemispheres
Speaker 1: really got going, that's right. And they discovered something that's
Speaker 1: that was seemingly amazing that if you split the brain,
Speaker 1: you that you essentially split the person as well in
Speaker 1: a certain sense and not in another sense. And we'll
Speaker 1: have to define that as we go on. But but
Speaker 1: but just think about it for a second. Just the
Speaker 1: the promise that the you know, the tease of this
Speaker 1: idea that there would be one person per hemisphere of
Speaker 1: the brain, this division of the self. Getting back to
Speaker 1: this idea in a certain sense of myself and the
Speaker 1: other guy, right right, Oh, that's right. Uh, the Robert
Speaker 1: Louis Stevenson and uh. And this is work they would
Speaker 1: have eventually earned Sperry the Nobel Prize in Medicine in Now.
Speaker 1: During this this these decades of research, Sperry performed experiments
Speaker 1: on cats, monkeys, and humans and focus a lot of
Speaker 1: attention on the neuron packed corpus colossum that bridges the hemispheres.
Speaker 1: This is often described as sort of like a broadband
Speaker 1: internet cable, like an internet backbone, fiber optic, or something
Speaker 1: that connects the two hemispheres together and enables most of
Speaker 1: the exchange of information between them. Right now, with non
Speaker 1: human animals, he surgically split the brains, producing what he
Speaker 1: called a split brain, in which each side seemed to
Speaker 1: function independently of the other. And he also found that
Speaker 1: an animal with a split brain could memorize double the information.
Speaker 1: Oh I didn't read that. Yeah, that was a tidbit
Speaker 1: I ran across creepy now. Obviously him not being a
Speaker 1: mad scientist villain in like a serial in a comic
Speaker 1: book or something. He didn't split human brains just for experiment,
Speaker 1: that's right. Fortunately for him, there were already humans walking
Speaker 1: around with split brains because they had had because there
Speaker 1: were patients who had had their corpus colossum separated, uh
Speaker 1: severed as a treatment for epilepsy, and so he was
Speaker 1: able to get a number of these individuals to volunteer
Speaker 1: for his experiments. Yes, so this procedure was not done
Speaker 1: for experiments, obviously, it was done as a medical treatment.
Speaker 1: And it's known as a corpus callosodomy, And so the
Speaker 1: theory behind it was that an epileptic seizure is sort
Speaker 1: of like a storm of activity in the brain with
Speaker 1: too many neurons firing and triggering chaotic activity all throughout
Speaker 1: both hemispheres, and the idea was if you cut the
Speaker 1: corpus colossum, if you sever that broadband internet connection between
Speaker 1: the two hemispheres of the brain, you limit the ability
Speaker 1: of one of these seizures to spread from one hemisphere
Speaker 1: of the brain to the other. And in many cases
Speaker 1: where severe epilepsy could not be treated by any other means,
Speaker 1: the surgery actually was considered effective, I think, especially later
Speaker 1: versions of the surgery, less so in the forties, more
Speaker 1: so I think in like the sixties on. But this
Speaker 1: surgery generally isn't used today because we have on on
Speaker 1: the whole safer, better, less radical treatments for epilepsy now.
Speaker 1: They're they're drugs that are pretty effective, and there are
Speaker 1: less radical surgeries you can do. And it's not known
Speaker 1: exactly how many patients ever received a corpus colisotomy, and
Speaker 1: history I've seen estimates including somewhere between fifty and a
Speaker 1: hundred total patients. I've read Michael Gazaniga estimated that there
Speaker 1: were over a hundred patients who had received And now,
Speaker 1: obviously not all of these patients volunteered for split brain
Speaker 1: neurology research, but some did. And one of the really
Speaker 1: interesting things to point out is that we'll have to
Speaker 1: keep coming back to this is that despite the radical
Speaker 1: nature of this surgical intervention, cutting the two hemispheres apart
Speaker 1: and basically preventing them from communicating with one another, most
Speaker 1: patients reported that their lives were generally normal after the surgeries.
Speaker 1: Their families did not usually report any major changes in behavior, personality,
Speaker 1: or cognitive ability. Uh. Michael Kazanaga says that generally, quote,
Speaker 1: you wouldn't know it if you were talking to such
Speaker 1: a patient. Yeah, I've read that. The really the only
Speaker 1: notable results of this, outside of, you know, perhaps some
Speaker 1: experimental of the stuff that's gonna come up, was that
Speaker 1: they didn't have the seizures anymore. Yeah, like that. That
Speaker 1: was the goal, and that was the the the primary
Speaker 1: of experiential difference. By and large, people underwent this procedure.
Speaker 1: It cut the two halves of their brain apart, and
Speaker 1: they seemed mostly unchanged. Now. On the other hand, I
Speaker 1: have read some anecdotes about changes certain patients faced, especially
Speaker 1: right after the surgery, during like an adaptation period. For example,
Speaker 1: article in Nature News by David Woolman recounts the experiences
Speaker 1: of a patient named Vicky, who received a calasotomy in
Speaker 1: nineteen seventy nine to treat terrible caesar she was having.
Speaker 1: There's a story that her seizures were so bad that
Speaker 1: one time she like fell on a stove and burned
Speaker 1: her back while she was having one. Um. And so
Speaker 1: she says that for the first few months after her surgery,
Speaker 1: she would stand in the grocery store trying to pick
Speaker 1: items off of the shelf, but having severe difficulty just
Speaker 1: picking up items. She says, quote, I'd reach with my
Speaker 1: right right hand for the thing I wanted, but the
Speaker 1: left would come in and they'd kind of fight, almost
Speaker 1: like repelling magnets. Uh. And she would apparently have similar
Speaker 1: troubles when trying to get dressed in the morning. Wolman writes, quote,
Speaker 1: Vicky couldn't reconcile what she wanted to put on with
Speaker 1: what her hands were doing. Sometimes she ended up wearing
Speaker 1: three outfits at once and then Vicky says, quote, I'd
Speaker 1: have to dump all the clothes on the bed to
Speaker 1: catch my breath and start again. And I've read other
Speaker 1: accounts along these lines that a few split brain patients
Speaker 1: described things like that this was one image one hand
Speaker 1: buttoning up a shirt and the other hand following immediately
Speaker 1: behind it and unbutton ing all the buttons. But these
Speaker 1: kind of these type of descriptions are apparently not typical.
Speaker 1: Most reports indicate that people's behavior, cognitive ability, personality, all
Speaker 1: that is mostly unchanged. And even in Vicki's case, after
Speaker 1: about a year, she was mostly back to normal in
Speaker 1: terms of everyday activities. She says, she could, you know,
Speaker 1: slice vegetables, to cook and and operate machines and all that.
Speaker 1: And this is in line with other reports. Amazingly, you
Speaker 1: can completely sever the connection between the two hemispheres of
Speaker 1: the brain, and most of the people you do this
Speaker 1: to function normally in day to day life afterwards, before
Speaker 1: even get to the other strange stuff we're talking about,
Speaker 1: that in itself seems crazy. Yeah, I am just always
Speaker 1: amazed when you when you hear about the things that
Speaker 1: can be done to the brain and the ways that
Speaker 1: the brain can can can bounce back and and behave
Speaker 1: just relatively normally or just or seemingly completely normally. Even
Speaker 1: in the face of catastrophic injuries, the brain can often
Speaker 1: find a way, the mind uh finds a way. But
Speaker 1: of course, despite these reports that people are generally unchanged,
Speaker 1: what we're about to talk about is that if you
Speaker 1: and what Sperry and Gazaniga discovered is if you apply
Speaker 1: some special conditions in the lab, you can see some
Speaker 1: really strange and thrilling things at work in the split
Speaker 1: brain patients. Yeah, the crux of this comes down to
Speaker 1: the very visual processing we discussed earlier. Left visual field,
Speaker 1: right side of the brain, right visual side field, left
Speaker 1: side of the brain. So in a split brain, the
Speaker 1: left side of the brain can't see the left field
Speaker 1: of vision and the right side of the brain can't
Speaker 1: see the right visual field, or generally can't generally, Yeah,
Speaker 1: generally speaking, and we'll we'll get into the meat of
Speaker 1: this in a minute. But but it's going to lead
Speaker 1: to split brain cats with eye patches and split brain
Speaker 1: monkeys with memorization. Because, as we mentioned again, he did
Speaker 1: conduct animal experiments to see how this UH to to
Speaker 1: to reveal what was going on. And the animal experiments
Speaker 1: were very they produced very strange and fascinating results. But
Speaker 1: you always wonder, well, okay, you know, animal brains are
Speaker 1: just different than human brains, so so what happens with
Speaker 1: the actual human So I was reading an account of
Speaker 1: their very first patients, very in Gazzaniga's very first split
Speaker 1: brain patient, uh in that that David Wollman article, and
Speaker 1: it was a man known as w J. A lot
Speaker 1: of times these patients are known just by a first
Speaker 1: name or by initials, you know, to protect their their identity.
Speaker 1: And apparently w J had served as a paratrooper in
Speaker 1: World War Two and he suffered a head injury. During
Speaker 1: the fighting, a Nazi had smashed him in the head
Speaker 1: with the rifle butt and afterward he experienced severe seizures
Speaker 1: and was treated with the callisotomy. And so in nineteen
Speaker 1: sixty two, after the surgery, Kazaniga ran visual field experiments
Speaker 1: with w J. And what he found was amazing. So
Speaker 1: the standard set up of one of these experiments is
Speaker 1: that you have the patient focus on a dot in
Speaker 1: the middle of a screen, and then you flash a
Speaker 1: visual stimulus in the peripheral visual field on one side
Speaker 1: or the other. And the scientists knew from previous research
Speaker 1: that this would mean stimuli shown to the left visual field,
Speaker 1: as we've been saying, would usually be perceived only by
Speaker 1: the right hemisphere, and stuff shown in the right visual
Speaker 1: field would be perceived only by the left hemisphere. But
Speaker 1: now that the hemispheres can't talk to each other anymore,
Speaker 1: what happens? So w J was shown images in his
Speaker 1: left or right visual fields and then asked to press
Speaker 1: a button and then asked to say what he saw.
Speaker 1: And when an image was shown to his left hemisphere,
Speaker 1: the part we know is primarily responsible for language, he
Speaker 1: had no problems at all. Right, you show the left
Speaker 1: brain whatever you want, a cat or you know, show
Speaker 1: him RoboCop, and then they'll press the button to indicate
Speaker 1: they saw something, and he'll say, I saw a RoboCop.
Speaker 1: But when they showed an image to w J's right hemisphere,
Speaker 1: what he said was that he saw nothing, But strangely enough,
Speaker 1: his left hand, which remember, of course, the left hand
Speaker 1: is connected to the right hemisphere, his left hand pressed
Speaker 1: the button when he saw the image, even though the
Speaker 1: part of his brain responsible for speech was saying out loud,
Speaker 1: I don't see anything. I mean, take take a second
Speaker 1: to think about that. Like when I first read that,
Speaker 1: I was like, oh, okay, oh, and then it hit
Speaker 1: me and I got the chills. I mean, you know,
Speaker 1: the hair stands up on the back of my neck. Literally. Yeah,
Speaker 1: Because what we're imagining here is we we read this
Speaker 1: and discussed it is It's not a complete selex like
Speaker 1: separation of self, right, It's like a temporary duality, like
Speaker 1: a flash of duality, where in the very place where
Speaker 1: we we want and expect to find some sort of
Speaker 1: continuity of self, well, it's yeah, it's like peeking in
Speaker 1: and seeing a quick glimpse of a reality that may
Speaker 1: be far more true and accurate a description of how
Speaker 1: the brain is than we would like to admit, or
Speaker 1: that normally seems true to us, because again, we always
Speaker 1: feel unified and the split brain patients feel unified. Will
Speaker 1: revisit this a little more, but they don't report feeling
Speaker 1: like two different people. They just feel normal. This is
Speaker 1: just how I am. And yet from an objective outsider's
Speaker 1: point of view, it's almost as if you've got two
Speaker 1: different people taking the test at the same time. One
Speaker 1: is registering I see something with a hand and the
Speaker 1: other is saying he doesn't see anything, and yet it
Speaker 1: only seems this way under certain conditions and only from
Speaker 1: the outside. Now, if you want to see an example
Speaker 1: of this, you can actually see one of these experiments
Speaker 1: demonstrated on film. There's like a short documentary segment feature
Speaker 1: that I think he's up on YouTube. Still there's a
Speaker 1: patient named to Joe who is working with Kazanega and
Speaker 1: this looks like it's the nineties or so, and uh,
Speaker 1: it demonstrates the typical experiment. So you show either words
Speaker 1: or pictures to the left brain only, and Joe can
Speaker 1: name them out loud just fine. So he you know,
Speaker 1: you show him the word car or a picture of
Speaker 1: a car. He says car. Show him the word grapes
Speaker 1: or picture of grapes. He says grapes. Everything seems normal
Speaker 1: because it's all going to the left hemisphere and that's
Speaker 1: the hemisphere that talks. You show a word to the
Speaker 1: right brain only. In this case, the word pan flashes
Speaker 1: on the far left side of the screen and suddenly
Speaker 1: Joe is stumped. Uh. Just based on my read, it
Speaker 1: looks to me like he seems to be aware that
Speaker 1: he saw something like there's a kind of recognition that
Speaker 1: it looks to me at least like he is aware
Speaker 1: something appeared but can't say what it is. And with
Speaker 1: a little shrug and a shaking of his head, he says,
Speaker 1: I didn't see it. But then Gazanega has him close
Speaker 1: his eyes and draw with his left hand, which is
Speaker 1: controlled mostly by the right hemisphere, and his left hand
Speaker 1: draws a pan. Oh wow, again legitimate chills. And of
Speaker 1: course after he draws it and looks at it with
Speaker 1: both eyes, he can say, yeah, I saw a pan,
Speaker 1: But the part of his brain that talks didn't seem
Speaker 1: to know he'd seen a pan until after his left
Speaker 1: hand drew it. Another type of experiment they carried out.
Speaker 1: You take a split brain patient and simultaneously show two
Speaker 1: different pictures on the two to the two different hemispheres.
Speaker 1: You show a hammer to the left hemisphere and you
Speaker 1: show a saw to the right hemisphere, and you ask
Speaker 1: what did you see. Of course, the speaking part of
Speaker 1: the brain says hammer. The person says, I saw a hammer.
Speaker 1: But then when asked to draw with the left hand,
Speaker 1: the patient draws a saw and you ask them why
Speaker 1: did you do that? And the patient in this one case,
Speaker 1: the case of Joe says I don't know. Now. In
Speaker 1: other cases like this versions of this test, sometimes the
Speaker 1: speaking part of the brain will not just say I
Speaker 1: don't know, but we'll actually see to make up stories
Speaker 1: about why their brain produced a certain output that the
Speaker 1: left part of the brain, the speaking part, doesn't seem
Speaker 1: to understand, and they'll just confabulate an explanation. Well, you know,
Speaker 1: they might say, well, because you know, I was thinking
Speaker 1: about this other thing, or because you said this thing earlier,
Speaker 1: or something, well that makes sense. I mean, it's almost
Speaker 1: like a supernatural experience, right, and uh, and you know,
Speaker 1: logically you can, you know, try and find some sort
Speaker 1: of answer to it. But the answer you give, and
Speaker 1: apparently the I mean, there's no indication that these people
Speaker 1: were just consciously lying about their motivations. The answer you give,
Speaker 1: and apparently the answer you seem to believe is not true.
Speaker 1: Is just like you. You can come up with explanations
Speaker 1: for your own behavior that are completely wrong, and we
Speaker 1: can show why they're wrong, but you are not aware
Speaker 1: that they're wrong. You can be wrong about your own mind, right,
Speaker 1: and even without a split brain, of course, humans are
Speaker 1: are very capable of of of coming up with false
Speaker 1: reasons for whatever they believe or whatever they did. Oh, absolutely, yeah,
Speaker 1: I think that's entirely correct. And that's sort of what
Speaker 1: I what I'm thinking we might be able to extrapolate here.
Speaker 1: So one of the most amazing things to me about
Speaker 1: this kind of research is, uh is that this can
Speaker 1: happen to the brain. For the most part, nobody seems
Speaker 1: to notice. It takes a lab experiment like this to
Speaker 1: draw it out like not the people who interact with
Speaker 1: the split brain patient. Remember that family members usually report
Speaker 1: no major changes in personality or cognitive ability. As David
Speaker 1: Wollman points out in his Nature article, the patients themselves
Speaker 1: say they quote never reported feeling anything less than whole.
Speaker 1: And in the words of Michael Gazaniga, the severed hemispheres
Speaker 1: do not seem to notice that they have been severed,
Speaker 1: and they don't report missing each other. So this raises
Speaker 1: so many questions. First of all, why are they connected
Speaker 1: in the first place. If they can be severed like
Speaker 1: this and not seem to notice that, that's an interesting thing, like,
Speaker 1: what's the reason for this this connection? Second, how is
Speaker 1: as possible? Like, how is it possible to cut a
Speaker 1: brain in half and have it not seem to notice
Speaker 1: anything's different and not behave much different. Indeed, I mean,
Speaker 1: even a light of everything we've talked about, it seems
Speaker 1: it seems kind of impossible. It seems seems like it's
Speaker 1: a like like like it's a magic trick, a grotesque
Speaker 1: magic trick, but a magic trick in the west. Well,
Speaker 1: maybe we should discuss a possible explanation for this after
Speaker 1: a break. Thank alright, we're back. Okay, So we're asking
Speaker 1: the question of how is it possible given these split
Speaker 1: brain experiments where uh, you sever the corpus closum, the
Speaker 1: two hemispheres of the brain are separated, and now functions
Speaker 1: that are dominated by one hemisphere of the brain or
Speaker 1: the other can can take place, can go on independently
Speaker 1: without the other part of the brain seeming to be aware.
Speaker 1: And this even leads to stuff like the right brain
Speaker 1: being aware of a piece of information that motivates action.
Speaker 1: Like say you show the right brain a picture, the
Speaker 1: left hand, which is mainly controlled by the right brain,
Speaker 1: can draw a picture of that thing, and the left
Speaker 1: brain doesn't know why it happened, And the person speaking
Speaker 1: gives a maybe a made up explanation of where that
Speaker 1: image came from. How is this kind of thing possible?
Speaker 1: Gazonica explains it in terms of what he sort of
Speaker 1: calls interpreter theory. The interpreter is the idea of the
Speaker 1: part of your brain. Gazaniga thinks this is localized in
Speaker 1: the left hemisphere that comes up with this contrived explanation
Speaker 1: for why your your brain did something that it doesn't
Speaker 1: actually understand. Uh. And we can know in many cases
Speaker 1: that this explanation is bunk because we know where the
Speaker 1: actual stimulus for the behavior came from. It was shown
Speaker 1: to the other half of the brain that the speaking
Speaker 1: part of the brain doesn't know about. And so Gazanica's
Speaker 1: idea is that this interpreter function, its main role is
Speaker 1: to create a sense of self, to sort of weave
Speaker 1: an autobiographical narrative about the self that makes sense, even
Speaker 1: if it makes sense in a completely false way, that
Speaker 1: does not actually explain the real things that happened in
Speaker 1: the real motivations for behavior. It just comes up with
Speaker 1: post talk explanations for behaviors. And you know, this reminds
Speaker 1: me of m I'm sure you've read about this before.
Speaker 1: There's a metaphor that's often used. I don't know where
Speaker 1: it comes from in the first place, but sometimes the
Speaker 1: psychologist Jonathan Height invokes it of the elephant and the rider,
Speaker 1: you know, to explain the conscious and unconscious brain. So
Speaker 1: in the case of the unconscious versus the conscious brain,
Speaker 1: the conscious mind is a person is like a person
Speaker 1: riding on top of an elephant, and the elephant is
Speaker 1: the unconscious mind. And the writer thinks they are driving,
Speaker 1: steering the elephant around, but actually the elephant goes where
Speaker 1: it wants, and the rider is just riding right there
Speaker 1: along for the ride wherever the elephant goes. Nevertheless, the
Speaker 1: writer will always be able to come up with some
Speaker 1: explanation for why they meant to steer the elephant in
Speaker 1: the direction it went right, like oh, yeah, yeah, I
Speaker 1: actually wanted to go over to that mud hole and
Speaker 1: get showered in mud because because I was hot and
Speaker 1: the mud is willing me off now. But in this scenario,
Speaker 1: the elephant, of course, is the one calling the shots.
Speaker 1: Actually right, I mean, yeah, elephants love mud holes right
Speaker 1: right now. Of course, not to be a stickler here
Speaker 1: to complicate the issue, but you could have a mahoot
Speaker 1: in there. I believe the term is is mahoot the
Speaker 1: individual who who will sometimes stand to the side and
Speaker 1: using a stick to touch different parts of the elephant
Speaker 1: um naked go where it needs to go. Oh well,
Speaker 1: we know quite well that often the unconscious mind of
Speaker 1: a person can be controlled by manipulation from the outside
Speaker 1: without the rider being aware that they're not driving. I mean,
Speaker 1: think about the ways people are are manipulated in their
Speaker 1: unconscious drives and desires, by advertising, by media, by drugs,
Speaker 1: by so all of these things are the stick of
Speaker 1: the mahoot, which I'm sure has a particular name that
Speaker 1: I'm not aware of. And then the mahoot is represents
Speaker 1: the interests of corporations and governments and uh and religious
Speaker 1: grew its, etcetera. It's driving somebody's unconscious mind around while
Speaker 1: they think they're the driver. I mean, no matter you know,
Speaker 1: the elephant is going to be calling the shots. See
Speaker 1: whether it's being manipulated or it's just following its nature.
Speaker 1: But either way, the driver is always going to be
Speaker 1: able to come up with the story saying, yeah, this
Speaker 1: is why we went over here. I have planned it
Speaker 1: this way all along. I wanted to buy this product. Now,
Speaker 1: this is a kind of different case, but the analogy
Speaker 1: here is that the talking, explaining, interpreting part of the
Speaker 1: left brain, according to Gazaniga's theory, is making up stories
Speaker 1: about why the now alien right brain does what it does, which,
Speaker 1: of course, it still shares a body so it controls
Speaker 1: some of the same limbs and stuff, when the interpreter
Speaker 1: really has no idea why the other part of the
Speaker 1: brain did what it did. Now, I think we should
Speaker 1: probably take a minute to emphasize like the drawbacks and
Speaker 1: limitations of split brain research, one of them is that,
Speaker 1: as riveting as I feel like, this kind of thing
Speaker 1: is um I think, for one, due to the necessity
Speaker 1: of the small sample sizes and the unusual history of
Speaker 1: the patients involved. This is the kind of research that's
Speaker 1: better thought of as a jumping off point to inspire
Speaker 1: questions and hypotheses that you should really try to prove
Speaker 1: through other means if possible. Like a lot of modern
Speaker 1: neuroscientists would probably say that you can learn more with
Speaker 1: more confidence from brain imaging studies like f M R
Speaker 1: I and stuff, then you can from a very small
Speaker 1: cohort of people with callis Otomy's right, right, but at
Speaker 1: the same time that that may be true. But I
Speaker 1: do think there's real value in these kind of experiments,
Speaker 1: specifically mainly because you can see it like you can
Speaker 1: see the human behavior in reality. You can see the
Speaker 1: implications of a strange discovery and neuroscience instantiated in the
Speaker 1: real world. It's one thing to learn through FMR I
Speaker 1: that something like different brain regions can function somewhat independently
Speaker 1: of one another, almost as multiple brains within the same
Speaker 1: head that don't understand what the other one is doing.
Speaker 1: You could probably show that in some ways through f
Speaker 1: m R I, but the split brain experiments show you
Speaker 1: the texture and the drama of the experience of a
Speaker 1: real person dealing with these facts about the brain. Other
Speaker 1: studies could probably find ways of indicating this, but but
Speaker 1: it is I think valuable how these experiments show the
Speaker 1: experience of it right, like you can actually see somebody
Speaker 1: in real time dealing with the fact that they don't
Speaker 1: understand why their left hand just did what it did.
Speaker 1: I was reading a little a little bit about this.
Speaker 1: I ran across, uh some material written by a cognitive psychologist,
Speaker 1: Jaar Pinto, an assistant professor at the Psychology Department of
Speaker 1: the University of Amsterdam in the Netherlands. And uh Pinto
Speaker 1: and their team tested to split brain patients in to
Speaker 1: see if they could respond accurately to objects in the
Speaker 1: left visual field perceived by the right brain, while also
Speaker 1: responding verbally or with the right hand control by the
Speaker 1: left brain. And Pinto uh Pinto also wrote about this
Speaker 1: in a piece for Ian magazine as well. So Pinto
Speaker 1: and the and and the team found that they could
Speaker 1: be that the individual could perceive stimuli and presence in
Speaker 1: either side of the visual field, but that they couldn't
Speaker 1: compare stimuli across the midline of the visual field. When
Speaker 1: the stimulus appeared in the left field, they were better
Speaker 1: at indicating its visual properties attention, and when it appeared
Speaker 1: in the right visual field, they were better at labeling it. So,
Speaker 1: you know, coming back to language, here's how Pinto summed
Speaker 1: it up in Ian magazine. I just want to read
Speaker 1: a passage from this because I think it it punctuates
Speaker 1: a lot of what we're talking about here. Quote. Based
Speaker 1: on these findings, we have proposed a new model of
Speaker 1: the split brain syndrome. When you split the brain, you
Speaker 1: still end up with only one person However, this person
Speaker 1: experiences two streams of visual information, one for each visual field,
Speaker 1: and that person is unable to integrate the two streams.
Speaker 1: It is as if he watches an out of sync movie,
Speaker 1: but not with the audio and video out of sync. Rather,
Speaker 1: the two unsinked streams are both video. And There's more.
Speaker 1: While the previous model provided strong evidence for materialism, split
Speaker 1: the brain, split the person, the current understanding seems to
Speaker 1: only deepen the mystery of consciousness. You split the brain
Speaker 1: into two halves, and yet you still have only one person.
Speaker 1: How does a brain consisting of many modules create just
Speaker 1: one person? And how do split brainers operate as one
Speaker 1: when these parts are not even talking to each other. Now,
Speaker 1: this study, I think, does add some interesting nuance to
Speaker 1: what we've been talking about before. One thing, I feel
Speaker 1: like I don't maybe I'm just missing something. I feel
Speaker 1: like Pinto is setting up this model as like uh
Speaker 1: as like a counterpoint to the idea of of what
Speaker 1: Spery and Gazaniga discovered. But it seems actually to me
Speaker 1: kind of in line with what they discovered, like the
Speaker 1: idea that that our consciousness is very mysterious. I mean,
Speaker 1: I think Spery and Gazaniga would say that despite being
Speaker 1: able to produce these behaviors that look from the outside
Speaker 1: like as if they're from two different people. Uh, the
Speaker 1: experience of the patient, as they've always reported, is that
Speaker 1: they feel like a normal, whole person, that nothing seems
Speaker 1: to have changed to them. Right. I think in both
Speaker 1: cases though, it just you end up in this weird
Speaker 1: conundrum almost, this paradox, this idea that the single person
Speaker 1: we feel that we are is in some ways too
Speaker 1: And in these cases where we see evidence of of
Speaker 1: seemed to see two evidence of what you could you know,
Speaker 1: call two minds within one brain, they're still functioning as one.
Speaker 1: They are still one. And so yeah, the paradox of
Speaker 1: that which is one seems too and that which is
Speaker 1: too seems one or more than two. Yeah, I mean
Speaker 1: that we've got the two hemispheres of the brain. But
Speaker 1: remember that the hemispheres are each full of you know,
Speaker 1: modules and the like. They're full of millions of neurons
Speaker 1: and they're that are working in different networks and modules
Speaker 1: to accomplish different goals. And so I think one of
Speaker 1: the lessons is that definitely different parts the brain can
Speaker 1: behave and generate behaviors independently and somehow you are here
Speaker 1: and you end up thinking I am a person. There's
Speaker 1: one of me, but there's a lot of different independent
Speaker 1: stuff going on inside whatever makes you. Yeah, I come
Speaker 1: back to that Hunter S. Thompson Warren Yvon quote, you're
Speaker 1: a whole different person when you're scared. Uh and in
Speaker 1: because in some of because in to some extent, as
Speaker 1: we've discussed, you are a different person. You're at least
Speaker 1: a different version of the person. Uh So, yeah, how
Speaker 1: many how many you's are there? Really? Well? I think
Speaker 1: we can explore this more in the second episode, but
Speaker 1: this really should give us some questions to think about,
Speaker 1: questions about whether our idea of a person or a
Speaker 1: self is really an accurate understanding of what brains are like,
Speaker 1: or is it just a is it just a convenient illusion?
Speaker 1: And that is some stuff to blow your mind or
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