Speaker 1: The powers of Hide seemed to have grown with the
Speaker 1: sickliness of Jackyal, and certainly the hate that now divided
Speaker 1: them was equal on each side. With Jekyll, it was
Speaker 1: a thing of vital instinct. He had now seen the
Speaker 1: full deformity of that creature that shared with him some
Speaker 1: of the phenomena of consciousness, and was co heir with
Speaker 1: him to death and beyond these links of community, which
Speaker 1: in themselves made the most poignant part of his distress.
Speaker 1: He thought of Hide for all his energy of life,
Speaker 1: as of something not only hellish but inorganic. This was
Speaker 1: the shocking thing that the slime of the pit seemed
Speaker 1: to utter, cries and voices, that the amorphous dust gesticulated
Speaker 1: and sinned, that what was dead and had no shape
Speaker 1: should usurp the offices of life. Welcome to stuff to
Speaker 1: Blow your mind from How Stuff Works dot Com. Hey
Speaker 1: you welcome to up to blow your mind. My name
Speaker 1: is Robert Lamb and I'm Joe McCormick and Robert. Why
Speaker 1: are you reading Robert Louis Stevenson at us Oh, Because
Speaker 1: that's from the Strange Case of Dr Jackel and Mr
Speaker 1: Hyde from eighteen eighty six, and it concerns the idea
Speaker 1: of there being two entities within the human skull, two
Speaker 1: 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 gonna
Speaker 1: be talking about today does, at least for me. Oh yeah,
Speaker 1: I mean, Robert Louis Stevenson was a fabulous writer and
Speaker 1: he's he's one of those authors that you can read
Speaker 1: today and it holds up so well. Did they ever
Speaker 1: make a good Jackal and Hyde movie. It's been a
Speaker 1: very long time since I've saw it, but there was
Speaker 1: an adaptation. It may have been a TV adaptation with
Speaker 1: Michael Caine Michael Kine. Yeah, And I remember really loving
Speaker 1: that and being quite disturbed by it as a child. Now,
Speaker 1: I was thinking there had to be a Jekyl and
Speaker 1: Hyde with Tim Curry as Jackal and Hyde. But I
Speaker 1: think maybe I'm confusing that with the Muppet Treasure Island,
Speaker 1: where he's You're thinking of the Muppet Jacky and High
Speaker 1: he's long John silver Man, that scene where he tramples
Speaker 1: Kermit to death is brutal. Well, yeah, so so we
Speaker 1: are we are beginning with kind of an erroneous model.
Speaker 1: But but I think helpful and because it is often
Speaker 1: easy to think of the brain as the thing itself, right,
Speaker 1: we fall into this center, our mode of of of
Speaker 1: of you know, the thinking of the brain body relationship
Speaker 1: as being a rider and its horse, when instead it
Speaker 1: is more this idea of a centaur, this this this
Speaker 1: one single entity, um, you know, and honestly, we see
Speaker 1: 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 un lockdown own. Uh you know, think of
Speaker 1: our imaginings, our inner thoughts versus our outer smile. And
Speaker 1: then there are all those disembodied brains and science fiction
Speaker 1: right from Crying and his robot body and teenaging Ninja
Speaker 1: Turtles to the Brain that Wouldn't Die Cane and RoboCop
Speaker 1: to one of the best I know that's one of
Speaker 1: one of your favorites as well, greatest of all time lovecrafts,
Speaker 1: The Whisper and Darkness, and so many Doctor Who characters,
Speaker 1: especially the Daleks brain guy from MST three Ky. We
Speaker 1: just keep keep coming up with these these visions of
Speaker 1: the brain as the just sort of the central human
Speaker 1: thought experience. You know, I never thought of this until now,
Speaker 1: but actually the brain guy from Mystery Science Theater is
Speaker 1: kind of a great illustration of Daniel Dennett's short story
Speaker 1: thought Experiment where am I I wonder if there was
Speaker 1: any connection there. Someone have to have to have to
Speaker 1: reach out to the the MST guys on that, you know,
Speaker 1: there are those like plot lines where his brain gets
Speaker 1: separated from him and somewhere else. Um. Of course, we
Speaker 1: know that things are not this simple. No brain is
Speaker 1: an island. It's affected by a host of outside influences,
Speaker 1: including all sorts of environmental nervous stimuli. And we're learning
Speaker 1: more and more about the role of our microbiome and
Speaker 1: various parasites in human cognition. But even if we're to
Speaker 1: just strip away all of that, if we're actually to
Speaker 1: become a brain and a tank, you know, Kane's brain
Speaker 1: in RoboCop two or or any of these sci fi
Speaker 1: visions take out all that external stuff, just the brain.
Speaker 1: We still have to contend with the fact that the brain,
Speaker 1: like a government, is composed of different houses. The brain
Speaker 1: consists 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 and are maybe sort of like different programs
Speaker 1: that run on that computer. But at least 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 is
Speaker 1: more harmful. But if you have, if you have a
Speaker 1: better understanding of how computer actually works, it could perhaps
Speaker 1: be a more helpful metaphor cuttle cats cuttle fish to
Speaker 1: the second oil age and kingdom with or of darkness.
Speaker 1: I don't dispute the eurostata, but if he's down here,
Speaker 1: we know not blood but darkness, the earth's black riches.
Speaker 1: No I could taste it on my lips. Today, I
Speaker 1: want to talk to you about the science of transgenesis
Speaker 1: tens genesis dot show now I wanted to to I
Speaker 1: think it would be helpful to just go ahead and
Speaker 1: consider one particular question right up top now. And we've
Speaker 1: certainly received questions like this following episodes in which brain
Speaker 1: hemispheres are discussed, such as our discussions on the bicameral
Speaker 1: mind hypothesis or the alphabet in the Goddess. Because there's
Speaker 1: this kind of pop understanding, right that each side of
Speaker 1: our brain controlled certain aspects of being, and that certain
Speaker 1: individuals have certain leanings that you know you have, right
Speaker 1: brain people left brain people, and that when that we
Speaker 1: can reconnect with our less favored hemisphere. Now, there certainly
Speaker 1: are some pieces of evidence that we're gonna look at
Speaker 1: in this episode that certain functions of human life are
Speaker 1: strongly lateralized in one half of the brain or the other,
Speaker 1: but they're not necessarily these functions or personality traits that
Speaker 1: are understood in popular consciousness like logic and creativity, right
Speaker 1: like taking or that you're gonna take some sort of
Speaker 1: a quiz online and find out if you're a right
Speaker 1: or lefty in terms of your brain. Now, a lot
Speaker 1: of these ideas apparently were popularized by nineteen seventy nine
Speaker 1: book title Drawing on the Right Side of the Brain
Speaker 1: by Betty Edwards. Uh, and the downstream myth that kind
Speaker 1: of uh, you know, took over a popular culture for
Speaker 1: a little bit. There is that, yeah, you had left
Speaker 1: side logic, right side creativity. And even in people who
Speaker 1: know better people, we still talk like this. I've noticed
Speaker 1: that I use this metaphor even though I know it's wrong,
Speaker 1: Like I will sometimes think of people as being very
Speaker 1: right brained or very left brained, even though that I
Speaker 1: know that that I've read before about how that's not correct. Well, likewise,
Speaker 1: if I hear it mentioned saying a yoga class, I'm
Speaker 1: gonna be less inclined. I'm not going to be the
Speaker 1: jerk in the yoga class that like perks up and
Speaker 1: says act l A, there's some interesting you know, I'm
Speaker 1: I'm gonna set back and enjoy the class because because
Speaker 1: it's one of those things that can can feel true. Right.
Speaker 1: But the idea goes back further than this particular book here.
Speaker 1: I mean, it goes back to some of the earlier
Speaker 1: discoveries that we're going to discuss here about hemispheric division. UM.
Speaker 1: You know, the ideas of neurologist Paul Broca who lived
Speaker 1: eighteen four through eighty French neurologist or Carl Vernica who
Speaker 1: lived who lived eighteen forty eight through nineteen o five,
Speaker 1: a German. They studied patients who had communication troubles due
Speaker 1: to brain injury UM, such as you know, left temporal
Speaker 1: lobe injuries, and they figured that this was the language center.
Speaker 1: Thus language was left hemisphere focus. And this is one
Speaker 1: thing that actually has been more born out by good
Speaker 1: research in in the history of neuroscience, is that one
Speaker 1: thing it's very clear the left hemisphere of the brain does,
Speaker 1: is it is dominant in language function. It's not that
Speaker 1: the right brain can't do any language, but it can't
Speaker 1: do a whole lot of language certainly can't do what
Speaker 1: the left hemisphere can do. Right Uh now we we
Speaker 1: kicked off the episode with reading from Robert Louis Stevenson
Speaker 1: against Scottish author He lived eighteen fifty eight and according
Speaker 1: to neuroscientist Elizabeth Waters, who's put together some you know,
Speaker 1: wonderful ted talks and ted ed videos about this, uh this, this,
Speaker 1: uh this topic, she points out that Robert Lewis Stevenson,
Speaker 1: in his book Strange Case of Dr Checkl and Mr Hyde,
Speaker 1: presented the notion of a logical left hemisphere that is
Speaker 1: in combat in you know, in in in in this
Speaker 1: uh this struggle with an emotional right hemisphere, and uh
Speaker 1: it's It's also worth noting that Robert Lewis Stevenson was
Speaker 1: also inspired by two popular French cases of individuals who
Speaker 1: exhibited dual personalities, uh their name. They were credited as
Speaker 1: being uh Felida X and Sergeant Fay. And these were
Speaker 1: apparently cases that were really you know, well covered in
Speaker 1: French and British press at the time. You know, it's
Speaker 1: kind of popular science influencing, uh, popular science fiction. Do
Speaker 1: you have any sense of whether what was presented to
Speaker 1: the public about these cases was largely accurate or was compleating.
Speaker 1: I don't, but I'd love to go back and look
Speaker 1: at it, because you know, this is a case where
Speaker 1: you can the science influences the science fiction, and the
Speaker 1: science fiction influences, uh to a certain extent, how the
Speaker 1: public thinks about a given topic. Now, other another influence
Speaker 1: on Robert Louis Stevenson. Apparently he had a just a
Speaker 1: terribly high fever, uh at one point during which he
Speaker 1: claimed to have experienced a split into which he experienced
Speaker 1: quote myself and quote that other fellow. Yeah, so this
Speaker 1: apparently had a big influence on him. An according to
Speaker 1: biograph 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 Treasury, and you know, his Space
Speaker 1: Adventure where long John Silver is at the same time
Speaker 1: a a patient 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 that like the side ruled by passion
Speaker 1: and the right brain and the side ruled by logic
Speaker 1: and 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 is 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, as a Spock
Speaker 1: or whatever the opposite of Spock would be in the
Speaker 1: Star Trek universe. To be clear, though, Yeah, the brain
Speaker 1: is divided into two hemispheres in internal regions like the striatum,
Speaker 1: the hypothalamus, the thalamus, and the brain stem. They're also
Speaker 1: organized with left and right sides as well, despite appearing
Speaker 1: to be continuous when you when you sort of look
Speaker 1: at illustrations of them. Yeah, and for the rest of
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 two arms and legs. For instance, the right
Speaker 1: hemisphere of the brain controls the left arm and leg,
Speaker 1: the left hemisphere controls the right arm and leg. Now
Speaker 1: I have read that in a way like both hemispheres
Speaker 1: can in some way to some degree control both arms.
Speaker 1: But that when it gets done to like fine motor
Speaker 1: control of like controlling the actions of the hand and
Speaker 1: especially that's where he gets really lateralized and like it's
Speaker 1: really going to be your right brain that's controlling what
Speaker 1: your left hand does with its fingers. Now, a more
Speaker 1: complex example is, but one it's extremely important is each
Speaker 1: eye has a left and right visual field, with the
Speaker 1: left visual field sent to the right hemisphere and the
Speaker 1: right field sent to the left hemisphere. Now this can
Speaker 1: also be misunderstood because I've seen it represented in the
Speaker 1: press in places that where like the left eye goes
Speaker 1: to the right hemisphere and the right eye goes to
Speaker 1: the left hemisphere. And that's not quite right either, because
Speaker 1: both hemispheres can get some information from both eyes. But
Speaker 1: it has to do with the side of the visual
Speaker 1: field that you're talking about. So like stuff that you
Speaker 1: perceive over to the left part of what you're looking
Speaker 1: at that goes to the right hemisphere, and stuff you
Speaker 1: perceive over in the right area of what you're looking
Speaker 1: at to the right of your center of vision that
Speaker 1: goes to the left hemisphere. And then our visual experience
Speaker 1: of reality it comes together from these two feeds. Movement
Speaker 1: and vision depend then on this uni hemispheric relationship. Now,
Speaker 1: why do our brains work this way? Yeah? Why the crossover?
Speaker 1: Why don't we just go straight up parallel? It's one
Speaker 1: of those things about the human vice 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 are most active. But we can't easily
Speaker 1: extend this idea to other aspects of cognition, and certainly
Speaker 1: not to the overall human experience or things like pure
Speaker 1: logical thinking or creativity. No, not that, But there are
Speaker 1: some cognitive functions that do appear to be pretty strongly
Speaker 1: lateralized in one way or another, And one of them,
Speaker 1: obviously is language. We mentioned this, Yeah, that's localized to
Speaker 1: the left, especially complex language and the power of speech.
Speaker 1: There's some research indicating that like the right brain might
Speaker 1: be able to have a sort of simple lexicon or
Speaker 1: understand very simple bits of language, but if you want
Speaker 1: to generate a sentence like speak one out loud, or
Speaker 1: understand complex instructions in language, this is usually going to
Speaker 1: be dominated by processes in the left hemisphere. Oh and
Speaker 1: we should also say that everything we say about hemispheres
Speaker 1: in this episode is going to be for most cases.
Speaker 1: There there cases where this is reversed, where people have
Speaker 1: like the switching of which hemisphere is dominant, but we're
Speaker 1: talking about the majority of cases here right now. Meanwhile, attention,
Speaker 1: we see that more localized to the right hemisphere. Yeah,
Speaker 1: and 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 neuroscientist Elizabeth Waters has pointed out among
Speaker 1: many others, logic and creativity are not these two distinct notions,
Speaker 1: you know, they're deeply interlinks, Like being good at logic
Speaker 1: is in many cases being a certain type of creative. Yeah.
Speaker 1: I mean, what you might dismiss is just a really
Speaker 1: logical exercise, like safe solving a complex math problem that
Speaker 1: may well require that will require some creative thinking. Likewise,
Speaker 1: a creative endeavor like say, writing a poem, finishing a novel,
Speaker 1: coming up with a cool joke, whatever, you know, those
Speaker 1: are gonna gonna be activities that also involve logic. In fact,
Speaker 1: some of what we're going to discuss in this pair
Speaker 1: of episodes in in the neuroscience research turns this whole
Speaker 1: thing on its head in a way, because the left
Speaker 1: part of the brain that's more dominant in exercises involving
Speaker 1: speech and language often tends to be the more creative
Speaker 1: one in explaining behaviors. Right it's the one that tends
Speaker 1: to interpret and come up with explanations for things as
Speaker 1: will as we'll talk about later on, which is a
Speaker 1: creative exercise. Whereas the right brain tends to more often
Speaker 1: be the part of the brain that records experiences accurately
Speaker 1: without creating explanations for them exactly. And but but certainly,
Speaker 1: if I'm gonna you know, drive home anything, we want
Speaker 1: to point out that that the creativity law, anything that
Speaker 1: employs these these two loose idea, you know, buckets of
Speaker 1: of of of cognition. You know, these are going to
Speaker 1: be products of whole brain cognition. Like our our the
Speaker 1: brain is all these areas of the brain are working together,
Speaker 1: uh to create this effect. Now, ultimately in this episode,
Speaker 1: we're going to be asking what happens when you cut
Speaker 1: those two hemispheres of the brain apart. Yes, but I
Speaker 1: guess we'll have to get to that after a break.
Speaker 1: All Right, we're back now. Before we get to the
Speaker 1: idea of severing the brain hemispheres, we should probably talk
Speaker 1: about a little more about Broca and Vernica. Yeah, these
Speaker 1: are just two really key individuals to this whole discussion
Speaker 1: 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: Karl Sagan's book Broke His Brain. Sagan describes at one
Speaker 1: point point holding a jar containing the noted scientist's brain. Wait,
Speaker 1: like imagining doing this literally doing literally doing it? Okay,
Speaker 1: holding holding the jar that contains his brain and thinking
Speaker 1: about like what you know, talking he talks a bit
Speaker 1: 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
Speaker 1: story with Broker's brain as the MacGuffin and it gets
Speaker 1: traded around and their car chases. Sagan is trying to
Speaker 1: get it back from the KGB spies. Uh no, not quite,
Speaker 1: but Dante Skull shows up as well. O nice So
Speaker 1: brokea 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 habilish. Columbia University anthropologist
Speaker 1: Ralph Holloway Sagan sided Uh's 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 palaeo anthropologist Philip Tobias also made this claim,
Speaker 1: though according to Susanne 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 as a discovery here broke a's 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 that 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
Speaker 1: now is to throw in the Nowadays, you hear more
Speaker 1: talk of networks as opposed to regions. You know, again
Speaker 1: getting into this idea that that that that we're looking
Speaker 1: at at a network of of of different systems and
Speaker 1: not individual areas that are just doing all the heavy lifting.
Speaker 1: Your brain is less like a computer. Maybe in more
Speaker 1: like the Internet, right, but a conscious Internet. That's scary.
Speaker 1: Uh so horror movie pitch the conscious Internet. Uh yeah,
Speaker 1: and 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, Well, thus the
Speaker 1: Vernica uh he was. He has another area of the
Speaker 1: brain'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
Speaker 1: really perfect. I mean, you could really almost it's tempting
Speaker 1: to just want to think like a left brain, right brain,
Speaker 1: old fashioned idea and have like the nineteen sixties hemisphere,
Speaker 1: in the nineteen seventies hemisphere. Right, there's just something something
Speaker 1: perfect about the post revolutionary hemisphere. Uh no, no, So
Speaker 1: we're gonna be talking about the research of neuroscientists named
Speaker 1: Roger Sperry and Michael Gazzaniga, and so actually the brain
Speaker 1: cutting started in the nineteen forties, but it was in
Speaker 1: the nineteen sixties that the research on people with severed
Speaker 1: hemispheres really got going, that's right. And they they discovered
Speaker 1: something that's that was seemingly amazing that if you split
Speaker 1: the brain, you you essentially split the person as well
Speaker 1: in a certain sense and not in another sense. And
Speaker 1: well we'll have to define that as we go on.
Speaker 1: But but but just think about it for a second.
Speaker 1: Just the the the promise that the you know, the
Speaker 1: tease of this idea that there would be one person
Speaker 1: per hemisphere of the brain, this division of the self.
Speaker 1: Getting back to this idea in a certain sense of
Speaker 1: myself and the other guy, right, yeah, oh, that's right. Uh,
Speaker 1: the Robert Louis Stevenson and h and this was work
Speaker 1: they would have eventually earned Sperry the Nobel Prize in
Speaker 1: Medicine in now. During this this these decades of research,
Speaker 1: Sperry performed experiments on cats, monkeys, and humans and focus
Speaker 1: a lot of attention on the neuron packed corpus colossum
Speaker 1: that bridges the hemispheres. This is often described as sort
Speaker 1: of like a broadband Internet cable, like an Internet backbone,
Speaker 1: fiber optic or something that connects the two hemispheres together
Speaker 1: and enables most of the exchange of information between them.
Speaker 1: Right now, with non human animals, he surgically split the brains,
Speaker 1: producing what he called a split brain, in which each
Speaker 1: side seemed to function independently of the other. And he
Speaker 1: also found that an animal with a split brain could
Speaker 1: memorize double the information. Oh I didn't read that. Yeah,
Speaker 1: that was a tidbit I ran across creepy now obviously
Speaker 1: him not being a mad scientist villain in like a
Speaker 1: serial in a comic book or something. He didn't split
Speaker 1: human brains just for experiment, that's right. Fortunately for him,
Speaker 1: there were already humans walking around with split brains because
Speaker 1: they had had because there were patients who had their
Speaker 1: corpus colossum separated uh severed as a treatment for epilepsy,
Speaker 1: and so he was able to get a number of
Speaker 1: these individuals to volunteer for his experiments. Yes, so this
Speaker 1: procedure was not done for experiments, obviously, it was done
Speaker 1: as a medical treatment, and it's known as a corpus callosodomy,
Speaker 1: and so the theory behind it is that an epileptic
Speaker 1: seizure is sort of like a storm of activity in
Speaker 1: the brain with too many neurons firing and triggering chaotic
Speaker 1: activity all throughout both hemispheres. And the idea was if
Speaker 1: you cut the corpus colosum, if you sever that broadband
Speaker 1: internet connection between the two hemispheres of the brain, you
Speaker 1: limit the ability of one of these seizures to spread
Speaker 1: from one hemisphere of the brain to the other. And
Speaker 1: in many cases where severe epilepsy could not be treated
Speaker 1: by any other means, the surgery actually was considered effective,
Speaker 1: I think, especially later versions of the surgery, less so
Speaker 1: in the forties, more so I think in like the
Speaker 1: sixties on. But this surgery generally isn't used today because
Speaker 1: we have on on the whole safer, better, less radical
Speaker 1: treatments for epilepsy. Now they're they're drugs that are pretty effective,
Speaker 1: and there are less radical surgeries you can do. And
Speaker 1: it's not known exactly how many patients ever received a
Speaker 1: corpus colisotomy and history I've seen estimates including somewhere between
Speaker 1: fifty and a hundred total patient. I read Michael Gazaniga
Speaker 1: estimated that there were over a hundred patients who had
Speaker 1: received one. Now, obviously not all of these patients volunteered
Speaker 1: for split brain neurology research, but some did. And one
Speaker 1: of the really interesting things to point out is that
Speaker 1: we'll have to keep coming back to this is that
Speaker 1: despite the radical nature of this surgical intervention, cutting the
Speaker 1: two hemispheres apart and basically preventing them from communicating with
Speaker 1: one another, most patients reported that their lives were generally
Speaker 1: normal after the surgeries. Their families did not usually report
Speaker 1: any major changes in behavior, personality, or cognitive ability. Uh.
Speaker 1: Michael Gazaniga says that generally, quote, you wouldn't know it
Speaker 1: if you were talking to such a patient. Yeah, I've
Speaker 1: read that the really the only notable results of this
Speaker 1: outside of you know, perhaps some experimental stuff that's gonna
Speaker 1: come up, was that they didn't have the seizures anymore. Yeah,
Speaker 1: like that. That was the goal, and that was the
Speaker 1: the the primary experiential difference. By and large, people underwent
Speaker 1: this procedure. It cut the two halves of their brain apart,
Speaker 1: and they seemed mostly unchanged. Now. On the other hand,
Speaker 1: I have read some anecdotes about changes certain patients faced,
Speaker 1: especially right after the surgery, during like an adaptation period.
Speaker 1: For example, a article in Nature News by David Woolman
Speaker 1: recounts the experiences of a patient named Vicky, who received
Speaker 1: a calisotomy in nineteen seventy nine to treat terrible caesar
Speaker 1: she was having. There's a story that her seizures were
Speaker 1: so bad that one time she like fell on a
Speaker 1: stove and burned her back while she was having one.
Speaker 1: Um And so she says that for the first few
Speaker 1: months after her surgery, she would stand in the grocery
Speaker 1: store trying to pick items off of the shelf, but
Speaker 1: having severe difficulty just picking up items. She says, quote,
Speaker 1: I'd reach with my right right hand for the thing
Speaker 1: I wanted, but the left would come in and they'd
Speaker 1: kind of fight almost like repelling magnets. Uh. And she
Speaker 1: would apparently have similar troubles when trying to get dressed
Speaker 1: in the morning. Woolman writes, quote, Vicky couldn't reconcile what
Speaker 1: she wanted to put on with what her hands were doing.
Speaker 1: Sometimes she ended up wearing three outfits at once. And
Speaker 1: then Vicky says, quote, I'd have to dump all the
Speaker 1: clothes on the bed to catch my breath and start again.
Speaker 1: And I've read other accounts along these lines that a
Speaker 1: few split brain patients described things like that this was
Speaker 1: one image one hand buttoning up a shirt and the
Speaker 1: other hand following immediately behind it and unbutton ing all
Speaker 1: the buttons. But these kinds of these type of descriptions
Speaker 1: are apparently not typical. Most reports indicate that people's behavior,
Speaker 1: cognitive ability, personality, all that is mostly unchanged. And even
Speaker 1: in Vicky's case, after about a year, she was mostly
Speaker 1: back to normal in terms of everyday activities. She says,
Speaker 1: she could, you know, slice vegetables, to cook and and
Speaker 1: operate machines and all that. And this is in line
Speaker 1: with other reports. Amazingly, you can completely sever the connection
Speaker 1: between the two hemispheres of the brain and most of
Speaker 1: the people you do this to function normally in day
Speaker 1: to day life afterwards, before we even get to the
Speaker 1: other strange stuff we're talking about that in itself seems crazy. Yeah,
Speaker 1: I am just always amazed when you when you hear
Speaker 1: about the things that can be done to the brain
Speaker 1: and the ways that the brain can can can bounce
Speaker 1: back and and behave just relatively normally or just or
Speaker 1: seemingly completely normally. Even in the face of catastrophic injuries.
Speaker 1: The brain can often find a way. The mind, uh
Speaker 1: finds a way. But of course, despite these reports that
Speaker 1: people are generally unchanged, what we're about to talk about
Speaker 1: is that if you and what Sparry and Kazaniga discovered
Speaker 1: is if you apply some special conditions in the lab,
Speaker 1: you can see some really strange and thrilling things at
Speaker 1: work in the split brain patients. Yeah, the crux of
Speaker 1: this comes down to the very visual processing we discussed earlier.
Speaker 1: Left visual field, right side of the brain, right visual field,
Speaker 1: left side of the brain. So in a split brain,
Speaker 1: the left side of the brain can't see the left
Speaker 1: field of vision and the right side of the brain
Speaker 1: can't 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 Gazaniga'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 engine read
Speaker 1: during the fighting, a Nazi had smashed him in the
Speaker 1: head with the rifle butt, and afterwards he experienced severe
Speaker 1: seizures and was treated with the callistotomy. And so in
Speaker 1: nineteen sixty two after the surgery, Becazanega ran visual field
Speaker 1: experiments with w J. And what he found was amazing.
Speaker 1: So the standard set up of one of these experiments
Speaker 1: is that you have the patient focus on a dot
Speaker 1: in the middle of a screen and then you flash
Speaker 1: a visual stimulus in the peripheral visual field on one
Speaker 1: side or the other. And the scientists knew from previous
Speaker 1: research that this would mean stimuli shown to the left
Speaker 1: visual field, as we've been saying, would usually be perceived
Speaker 1: only by the right hemisphere, and stuff shown in the
Speaker 1: right visual field would be perceived only by the left hemisphere.
Speaker 1: But 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 robo cop.
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 we're imagining here is we we read
Speaker 1: this and discussed it is. It's not a complete sle
Speaker 1: like separation of self, but it's like a temporary, very duality,
Speaker 1: like a flash of duality, where in the very place
Speaker 1: where we we want and expect to find some sort
Speaker 1: of continuity of self, well, it's yeah, it's like peeking
Speaker 1: in and seeing a quick glimpse of a reality that
Speaker 1: may be far more true and accurate a description of
Speaker 1: how the brain is than we would like to admit,
Speaker 1: or that normally seems true to us. Because again, we
Speaker 1: always feel unified and the split brain patients feel unified
Speaker 1: will revisit this a little more, but they don't report
Speaker 1: feeling like two different people. They just feel normal. This
Speaker 1: is just how I am. And yet from an objective
Speaker 1: outsider's point of view, it's almost as if you've got
Speaker 1: two different people taking the test at the same time.
Speaker 1: One is registering I see something with a hand and
Speaker 1: the other is saying he doesn't see anything. And yet
Speaker 1: it only seems this way under certain conditions, and only
Speaker 1: from the outside. Now, if you want to see an
Speaker 1: example of this, you can actually see one of these
Speaker 1: experiments demonstrated on film. And there's like a short documentary
Speaker 1: segment feature that I think he's up on YouTube. Still
Speaker 1: there's a patient name to Joe who is working with
Speaker 1: Kazanega and this looks like it's the nineties or so,
Speaker 1: and uh, it demonstrates a typical experiment. So you show
Speaker 1: either words or pictures to the left brain only, and
Speaker 1: Joe can name them out loud just fine. So he
Speaker 1: you know, you show him the word car or a
Speaker 1: picture of a car. He says car. Show him the
Speaker 1: word grapes or picture of grapes. He says grapes. Everything
Speaker 1: seems normal because it's all going to the left hemisphere,
Speaker 1: and that's the hemisphere that talks. You show a word
Speaker 1: to the right brain, only in this case, the word
Speaker 1: pan flashes on the far left side of the screen,
Speaker 1: and suddenly Joe is stumped. Uh just based on my read,
Speaker 1: it looks to me like he seems to be aware
Speaker 1: that he saw something, Like there's a kind of recognition
Speaker 1: that it looks to me at least like he is
Speaker 1: aware something appeared but can't say what it is. And
Speaker 1: with a little shrug and a shaking of his head,
Speaker 1: he says, I didn't see it. But then Gazzaniga has
Speaker 1: him close his eyes and draw with his left hand,
Speaker 1: which is controlled mostly by the right hemisphere, and his
Speaker 1: left hand draws a pan. Again legitimate chills, And of course,
Speaker 1: after he draws it and looks at it with both eyes,
Speaker 1: he can say, yeah, I saw a pan, But the
Speaker 1: part of his brain that talks didn't seem to know
Speaker 1: he'd seen a pan until after his left hand drew it.
Speaker 1: Another type of experiment they carried out. You take a
Speaker 1: split brain patient and simultaneously show two different pictures on
Speaker 1: the two to the two different hemispheres. You show a
Speaker 1: hammer to the left hemisphere and you show a saw
Speaker 1: to the right hemisphere and you ask what did you see.
Speaker 1: Of course, the speaking part of the brain says hammer.
Speaker 1: The person says I saw a hammer. But then when
Speaker 1: asked to draw with the left hand, the patient draws
Speaker 1: a saw and you ask them why did you do that,
Speaker 1: and the patient in this one case, the case of Joe,
Speaker 1: says I don't know. Now. In other cases like this
Speaker 1: version of this test, sometimes the speaking part of the
Speaker 1: brain will not just say I don't know, but will
Speaker 1: actually seem to make up stories about why their brain
Speaker 1: produced a certain output that the left part of the brain,
Speaker 1: the speaking part, doesn't seem to understand, and they'll just
Speaker 1: confabulate an explanation. Well, you know, they might say, well,
Speaker 1: because you know, I I was thinking about this other thing,
Speaker 1: or because you said this thing earlier, or something, well
Speaker 1: that makes sense. I mean, it's almost like a supernatural experience, right,
Speaker 1: and uh. And you know, logically you can, you know,
Speaker 1: try and find some sort of answer to it. But
Speaker 1: the answer you give, and apparently the I mean, there's
Speaker 1: no indication that these people were just consciously lying about
Speaker 1: their motivations. The answer you give, and apparently the answer
Speaker 1: you seem to believe is not true. It is just
Speaker 1: like you. You can come up with explanations for your
Speaker 1: own behavior that are completely wrong, and we can show
Speaker 1: why they're wrong, but you are not aware that they're wrong.
Speaker 1: You can be wrong about your own mind. And even
Speaker 1: without a split brain, of course, humans are are very
Speaker 1: capable of of of coming up with false reasons for
Speaker 1: 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 Gazzaniga, 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: this 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 in a light of everything we've talked about, it
Speaker 1: seems it seems kind of impossible. It seems seems like
Speaker 1: it's a like like like it's a magic trick, a
Speaker 1: grotesque 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 thank Alright, we're back. Okay, So we're
Speaker 1: asking the question of how is it possible given these
Speaker 1: split brain experiments where uh, you sever the corpus closum,
Speaker 1: the two hemispheres of the brain are separated, and now
Speaker 1: functions that are dominated by one hemisphere of the brain
Speaker 1: or the other can can take place, can go on
Speaker 1: independently without the other part of the brain seeming to
Speaker 1: be aware and This even leads to stuff like the
Speaker 1: right brain being aware of a piece of information that
Speaker 1: motivates action. Like say you show the right brain a picture,
Speaker 1: the 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: Gazanica 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 Um, 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 writer is just writing 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 cooling 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 now.
Speaker 1: Of course, not to be a stickler here to complicate
Speaker 1: the issue, but you could have a mahoot in there.
Speaker 1: I believe the term is is mahoot the individual who
Speaker 1: who will sometimes stand to the side and using a
Speaker 1: stick to touch different parts of the elephant, um naked
Speaker 1: go where it needs to go. Oh well, we know
Speaker 1: quite well that often the unconscious mind of a person
Speaker 1: can be controlled by manipulation from the outside without the
Speaker 1: rider being aware that they're not driving. I mean, think
Speaker 1: about the ways people are are manipulated in their unconscious
Speaker 1: drives and desires by advertising, by media, by drugs, by
Speaker 1: so all of these things are the stick of the mahoot,
Speaker 1: which I'm sure has a particular name that I'm not
Speaker 1: aware of. And then the mahoot is it represents the
Speaker 1: interests of corporations and governments and uh and religious groups, etcetera.
Speaker 1: It's driving somebody's unconscious mind around while they think they're
Speaker 1: the driver. I mean, no matter you know, the elephant
Speaker 1: is going to be calling the shots. See whether it's
Speaker 1: being manipulated or it's just following its nature. But either way,
Speaker 1: the driver is always going to be able to come
Speaker 1: up with the story saying, yeah, this is why we
Speaker 1: went over here. I have planned it this way all along.
Speaker 1: I wanted to buy this product. Now, this is a
Speaker 1: kind of different case, But the analogy here is that
Speaker 1: the talking, explaining, interpreting part of the left brain, according
Speaker 1: to Gazaniga's theory, is making up stories about why the
Speaker 1: now alien right brain does what it does, which, of course,
Speaker 1: it still shares a body so it controls some of
Speaker 1: the same limbs and stuff, when the interpreter really has
Speaker 1: no idea why the other part of the brain did
Speaker 1: what it did. Now, I think we should probably take
Speaker 1: a minute to emphasize like the drawbacks and limitations of
Speaker 1: split brain research. One of them is that, as riveting
Speaker 1: as I feel like, this kind of thing is um
Speaker 1: I think, for one thing, due to the necessity of
Speaker 1: the small sample sizes and the unusual history of the
Speaker 1: patients involved, this is the kind of research that's better
Speaker 1: thought of as a jumping off point to inspire questions
Speaker 1: and hypotheses that you should really try to prove through
Speaker 1: other means if possible. Like a lot of modern neuroscientists
Speaker 1: would probably say that you can learn more with more
Speaker 1: confidence from brain imaging studies like f m R I
Speaker 1: and stuff, then you can from a very small cohort
Speaker 1: of people with calls. Otomy's right, right, But at the
Speaker 1: same time that that may be true. But I do
Speaker 1: think there's real value in these kind of experiments, specifically
Speaker 1: mainly because you can see it, like you can see
Speaker 1: the human behavior in reality. You can see the implications
Speaker 1: of a strange discovery in neuroscience instantiated in the real world.
Speaker 1: It's one thing to learn through fmr I. That's something
Speaker 1: like different brain reach can function somewhat independently of one another,
Speaker 1: almost as multiple brains within the same head that don't
Speaker 1: understand what the other one is doing. You could probably
Speaker 1: show that in some ways through fm R I, But
Speaker 1: the split brain experiments show you the texture and the
Speaker 1: drama of the experience of a real person dealing with
Speaker 1: these facts about the brain. Other studies could probably find
Speaker 1: ways of indicating this, but but it is I think
Speaker 1: valuable how these experiments showed the experience of it right,
Speaker 1: like you can actually see somebody in real time dealing
Speaker 1: with the fact that they don't understand why their left
Speaker 1: hand just did what it did. I was reading a
Speaker 1: little a little bit about this. I ran across uh
Speaker 1: some material written by a cognitive psychologist, Year Pinto, an
Speaker 1: assistant professor at the Psychology department of the University of
Speaker 1: Amsterdam in the Netherlands. And uh Pinto and their team
Speaker 1: tested to split brain patients in to see if they
Speaker 1: could respond accurately to objects in the left visual field
Speaker 1: perceived by the right brain while also responding verbally or
Speaker 1: with the right hand controlled by the left brain. And
Speaker 1: Pinto uh Pinto also wrote about this in a piece
Speaker 1: for Ian magazine as well. So Pinto and the and
Speaker 1: and the team found that they could be that the
Speaker 1: individual could perceive stimuli and presence in either side of
Speaker 1: the visual field, but that they couldn't compare stimuli across
Speaker 1: the midline of the visual field. When the stimulus appeared
Speaker 1: in the left field, they were better at indicating its
Speaker 1: visual properties attention, and when it appeared in the right
Speaker 1: visual field, they were better at labeling it. So, you know,
Speaker 1: coming back to a language, here's how Pinto summed it
Speaker 1: up in Ian magazine. I just want to read a
Speaker 1: passage from this because I think it it punctuates a
Speaker 1: lot of what we're talking about here. Quote. Based on
Speaker 1: these findings, we have proposed a new model of the
Speaker 1: split brain syndrome. When you split the brain, you still
Speaker 1: end up with only one person. However, this person experiences
Speaker 1: 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 UNSYNCD 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 Gazzaniga 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 Gazaniga would say that despite being able
Speaker 1: to produce these behaviors that look from the outside like
Speaker 1: as if they're from two different people. Uh, the experience
Speaker 1: of the patient, as they've always reported, is that they
Speaker 1: feel like a normal, whole person that nothing seems to
Speaker 1: have changed to them, right. I think in both cases though,
Speaker 1: it just you end up in this weird conundrum almost,
Speaker 1: this paradox, this idea that the single person we feel
Speaker 1: that we are is in some ways too And in
Speaker 1: these cases where we see evidence of of seem to
Speaker 1: see two evidence of what you could you know, call
Speaker 1: 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, modules,
Speaker 1: and like they're full of millions of neurons and they're
Speaker 1: that are working in different networks and jules to accomplish
Speaker 1: different goals. And so I think one of the lessons
Speaker 1: is that definitely different parts of the brain can behave
Speaker 1: and generate behaviors independently. And somehow you are here and
Speaker 1: you end up thinking I am a person. There's one
Speaker 1: of me, but there's a lot of different independent stuff
Speaker 1: going on inside whatever makes you. Yeah, I come back
Speaker 1: to that Hunter S. Thompson Warren Yvon quote, you're a
Speaker 1: whole different person when you're scared. Uh and in because
Speaker 1: in some because in to some extent, as we've discussed,
Speaker 1: you are a different person. You're at least a different
Speaker 1: version of the person. Uh So, yeah, how many how
Speaker 1: many us are there? Really? Well? I think we can
Speaker 1: explore this more in the second episode, but this really
Speaker 1: should give us some questions to think about, questions about
Speaker 1: whether our idea of a person or a self is
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