Speaker 1: Hey, you welcome to Stuff to blow your mind. This
Speaker 1: is Robert Lamb and I'm Joe McCormick, and it's Saturday
Speaker 1: time for a Vault episode. This one originally aired September
Speaker 1: twenty nine. Rob, this was the interview that you did
Speaker 1: with the neuroscientist David Eagleman. Yeah, this is a lot
Speaker 1: of fun gets that he gets into some really cool ideas.
Speaker 1: Here a possible explanation for what dreams are for? And uh,
Speaker 1: one of my favorite parts, how in which ways? Uh?
Speaker 1: Is the human brain like a Mr Potato Is a
Speaker 1: Mr Potato different from Mr potato Head? Well it's Mr
Speaker 1: potato Head. Yes, Uh oh, I guess actually it's not
Speaker 1: Mr It's just potato Head now right, Well, I think
Speaker 1: now there is still a Mr. Potato Head, but there's
Speaker 1: also a broader potato head concept. Okay, yeah, I haven't
Speaker 1: followed all the potato head news, but I've I've caught
Speaker 1: wind of some of the like the faux outrage over
Speaker 1: over some of it. So at any rate, it's a
Speaker 1: eagle and uses the potato head um as a wonderful
Speaker 1: metaphor for exactly how our brain works when you plug
Speaker 1: different sensory inputs into it, so I highly recommend it.
Speaker 1: It's a great, great, really enjoyable interview. I enjoyed it.
Speaker 1: I think folks will enjoy it as well. Welcome to
Speaker 1: Stuff to Blow Your Mind, production of My Heart Radio. Hey,
Speaker 1: welcome to Stuff to Blow Your Mind. My name is
Speaker 1: Robert Lamb. Joe is away from work. He's realigning his
Speaker 1: gray matter at the moment, so it's just me today,
Speaker 1: but I'll be joined by neuroscientist, author, and science communicator
Speaker 1: David Eagleman about his new book Live Wired, The Inside
Speaker 1: Story of the Ever Changing Brain. Now we've mentioned David
Speaker 1: Eagelman on the show many times before. He's an adjunct
Speaker 1: professor at Stanford University and his CEO of Neo Sensory,
Speaker 1: a company that develops devices for sensory substitution. You may
Speaker 1: also know him from his previous books about the human brain,
Speaker 1: his TV series The Brain with David Eagleman, and his
Speaker 1: role as a scientific advisor on HBO's Westworld and the
Speaker 1: TNT series Perception. I'm recording this on a Monday, and
Speaker 1: I actually read Live Wired over the weekend. It's a
Speaker 1: highly addictive read and one that I think our listeners
Speaker 1: will will really enjoy. David does an amazing job breaking
Speaker 1: down the inner workings of the brain via relatable pop
Speaker 1: culture and historical metaphorth everything from the colonization of the
Speaker 1: America's to Mr Potato Head and Ellen Ripley from Aliens.
Speaker 1: It's published by Pantheon Books and you can currently grab
Speaker 1: it as a hardcover, an e book, or an audio book.
Speaker 1: And the fun thing is that that David reads the
Speaker 1: audio book. It's always great when you when you get
Speaker 1: that with an audio book. So, without without any further ado,
Speaker 1: let's jump right in. David Eagleman, thanks for joining me today.
Speaker 1: Great to be here, Robert. First of all, I have
Speaker 1: I just have to say that this book was such
Speaker 1: an engaging read. I actually read it all over the weekend,
Speaker 1: and while I was familiar with some of the findings
Speaker 1: and technologies discussed, there was plenty I hadn't been exposed
Speaker 1: to yet, and it was all delivered in such a
Speaker 1: fashion that it all ended up feeling like, you know,
Speaker 1: it's kind of like a revelation, um, and I feel
Speaker 1: like that revelation is really well summarized in the title
Speaker 1: of the book, Live Wired. If you would, could you
Speaker 1: summarize the basic difference between the idea of the live
Speaker 1: wired understanding of our brain as opposed to previous notions
Speaker 1: of how the brain worked. Yeah, I mean the whole
Speaker 1: The whole thing is that when you first pick up
Speaker 1: a neuroscience textbook as a young person, you see a
Speaker 1: picture of the brain and it says this parts or vision,
Speaker 1: this parts are hearing, the parts are touch, and so on.
Speaker 1: But in fact, um, I guess what I've spent the
Speaker 1: last twenty years, you know, in my laboratory really understanding
Speaker 1: the lesson of is that the brain is a is
Speaker 1: a dynamic system that's constantly moving around. And so for example,
Speaker 1: if you go blind, the part that we would have
Speaker 1: called your visual system gets taken over by hearing and touch.
Speaker 1: If you lose an arm, the part of your body
Speaker 1: map that has an arm gets taken over by neighboring
Speaker 1: areas and so on. The whole thing is this incredibly
Speaker 1: dynamic system. It's not like anything that we know how
Speaker 1: to build. Um. You know, here in Silicon Valley where
Speaker 1: I live, everything is about hardware and software, and engineers
Speaker 1: are praised for building an efficient system where you've got
Speaker 1: these two layers and that's it. Um. But what's happening
Speaker 1: in our skulls is an entirely different kind of technology,
Speaker 1: and so I in the book, I ended up coining
Speaker 1: a new term for this, live wired or live ware.
Speaker 1: And the idea with live ware is that every moment
Speaker 1: of your life, this is reconfiguring itself. So you've got
Speaker 1: eighty six billion neurons, these are the cell types of
Speaker 1: the brain. You've got about point to quadrillion connections, and
Speaker 1: every moment in your life, these things are changing their
Speaker 1: strength of connection. They're unplugging, they're replugging elsewhere, they're seeking around.
Speaker 1: What you have are these dense jungles. And you know,
Speaker 1: this level of complexity is something that bankrupts our language.
Speaker 1: We don't have any way of talking about point two
Speaker 1: quadrillion connections moving and changing. But everything in your life,
Speaker 1: every experience that you have um changes who you are.
Speaker 1: When you learn, for example, that my name is David,
Speaker 1: there's a physical change in the structure of your brain.
Speaker 1: And that's what it means for you to then remember,
Speaker 1: you know, two months later, who's the guy you had
Speaker 1: on your podcast David. You know, it's like it's it's
Speaker 1: this constantly changing system and it's UM unlike anything that
Speaker 1: we know how to build at the moment. So, um,
Speaker 1: you know, as you as you saw in the book.
Speaker 1: I tell these different stories just by way of introduction
Speaker 1: that are so fascinating, Like you can take out half
Speaker 1: the brain in a child. For example, when children have
Speaker 1: this really bad type of epilepsy, there's a surgery that
Speaker 1: they go through. Half the brain is removed, and they're
Speaker 1: just fine cognitively, they're totally fine because the rest of
Speaker 1: their brain, the other half says, okay, I'm gonna read
Speaker 1: are the functions that are that went missing from there.
Speaker 1: Sometimes a child is born with only half a brain,
Speaker 1: you know, and things just get get rewired so that
Speaker 1: it all is there and we can't you know, you
Speaker 1: can't do this with your cell phone or your computer.
Speaker 1: You can't take out half the circuitry and expect it
Speaker 1: to still function. But it works just fine, especially with
Speaker 1: a young brain. Now, with all of this in mind,
Speaker 1: into this live wired understanding of the brain in mind, um,
Speaker 1: I thought we might back up to a very basic question,
Speaker 1: uh that sometimes I guess we don't think about because
Speaker 1: we're I mean, we were trapped in the brain. We
Speaker 1: can't see the forest for the trees. But what what
Speaker 1: does the brain do? So the brain is locked in
Speaker 1: silence and darkness inside the vault of your skull, and
Speaker 1: all it's trying to do is make a model of
Speaker 1: the world, as in, I've got all this incoming data.
Speaker 1: And by the way, the data that comes into the
Speaker 1: brain is just spikes, just little electrical spikes in these neurons.
Speaker 1: It doesn't know that these spikes represent photons, and these
Speaker 1: spikes represent air compression waves, and these spikes represent mixtures
Speaker 1: of molecules hitting a membrane and so on. All it
Speaker 1: knows is I've got data coming in as zeroes and
Speaker 1: ones and um and it knows that it can control
Speaker 1: a body. And so it's job is to figure out,
Speaker 1: all right, how do I control the body, how does
Speaker 1: that change the spikes coming in? And how do I
Speaker 1: make a model of the world. And this is an
Speaker 1: extraordinary technology that we have carrying around on our shoulders.
Speaker 1: Um As I said, we we don't know how to
Speaker 1: build technology like this, and we're just scratching the surface
Speaker 1: of even trying to figure this out. But that's what
Speaker 1: the brain is doing, locked in its in its vault,
Speaker 1: is figuring out, okay, how do I understand the world,
Speaker 1: and and it's really extraordinarily good at at extracting patterns
Speaker 1: and eventually making predictions. And um, yeah, that is that
Speaker 1: is the main job that is trying to accomplish. Now,
Speaker 1: the big part of the book deals with how our senses,
Speaker 1: uh you know, speak to the brain and how the
Speaker 1: rain works around limitations uh, such as they are the
Speaker 1: ones you mentioned with the half of the brain being
Speaker 1: missing at etcetera. And also uh you know, relating limbs
Speaker 1: uh and uh and I love how you use these
Speaker 1: various metaphors to explain that to the reader. Would you
Speaker 1: mind uh explaining to our listeners how our brains are
Speaker 1: like Mr potato head. Yeah, so this is something that
Speaker 1: struck me many years ago where I realized that, so
Speaker 1: we've got all these sensors like our eyes and our
Speaker 1: ears and our nose and our fingertips, all these things
Speaker 1: were used to and so we just sort of think
Speaker 1: of these as fundamental. But but when you look across
Speaker 1: the animal kingdom, what you find are all these other
Speaker 1: weird kinds of sensors, things that you could take in
Speaker 1: like snakes taken infrared information, honeybees taken ultra violet when
Speaker 1: you look at something like the black ghost knifefish, it
Speaker 1: has electro receptors where it's pulling in information about perturbations
Speaker 1: and electrical fields. UM. Lots of birds and cows and
Speaker 1: insects have magneto reception where they are picking up on
Speaker 1: the magnet field of the planet and they're navigating that
Speaker 1: way and so on. And what I realized is Mother
Speaker 1: Nature doesn't actually have to recreate the brain every time
Speaker 1: she does this. Instead, the principles of brain operation, she's
Speaker 1: figured that out at the beginning, and then she can
Speaker 1: just plug in anything she wants in terms of what
Speaker 1: is the information that would be useful to sense. And
Speaker 1: that's why I suggested this potato head model of how
Speaker 1: to think about this, which is to say, you just
Speaker 1: take any sensors and you stick it in and it's
Speaker 1: good to go. The brain figures out, Okay, I've got
Speaker 1: this kind of spikes coming in UM, and it seems
Speaker 1: to correlate with this other sense, and it seems to
Speaker 1: allow me to find food or avoid predators or whatever.
Speaker 1: And so it just figures out what to do with
Speaker 1: that information. And so this is a very new kind
Speaker 1: of way to think about the brain. It's essentially understanding
Speaker 1: the brain as a general purpose compute device. You feed
Speaker 1: in whatever kind of data stream you want, and it's
Speaker 1: and it's good to go. And this, you know, explains
Speaker 1: a lot of what happens evolutionarily with janet x. It
Speaker 1: just what it allows mother nature to do is just
Speaker 1: tweak around with the genetics to make new kinds of sensors.
Speaker 1: But one of the really amazing things you discussed in
Speaker 1: this is that is that you can plug an eye
Speaker 1: into an ear hole or an ear into an eye
Speaker 1: hole on the Mr Potato head of our of our brain,
Speaker 1: and the brain will roll with the data that that's
Speaker 1: exactly right. And so this is an area called sensory substitution,
Speaker 1: which is to say, you can feed information into the
Speaker 1: brain via an unusual channel. And so something I started
Speaker 1: in my lab about ten years ago was seeing if
Speaker 1: we could build sensory substitution for people who are deaf.
Speaker 1: So what we do. We started by building this as
Speaker 1: a vest with vibratory motors in it. So you've got
Speaker 1: a whole bunch of little buzzers like the buzzer in
Speaker 1: your cell phone, and um, it captures sound and turns
Speaker 1: out into patterns of vibration on the torso. And it
Speaker 1: turns out that that worked really well. We could get
Speaker 1: people who are profoundly deaf to start understanding what is
Speaker 1: happening in the auditory world, just predicated on this spatio
Speaker 1: temporal pattern of vibrations on their skin. And the reason
Speaker 1: it worked is because it doesn't matter how the information
Speaker 1: gets to the brain. As long as it gets there,
Speaker 1: the brain will establish the correlations and figure out what
Speaker 1: to do with it. So, as an example, if you see,
Speaker 1: you know, the dog's mouth moving and you feel the
Speaker 1: buzzing on your skin, you know, your brain puts that
Speaker 1: together really easily. Or you know, you see somebody speaking,
Speaker 1: or or we train people by showing a word and
Speaker 1: you you know, you feel the word on the vest
Speaker 1: and you start understanding what's going on. So what we
Speaker 1: did then is we shrunk it down to the size
Speaker 1: of a wrist band. And because you and I are
Speaker 1: on video, Robert, you can see the wristband that I'm
Speaker 1: wearing right now. It's you know, it looks about the
Speaker 1: size of a fitbit, and it has very sophisticated computation
Speaker 1: in here where it's capturing sound and turning that into
Speaker 1: patterns vibration around the skin of the wrist and um.
Speaker 1: So what we've been doing is we uh this Actually
Speaker 1: now I spun a company out of my lab called
Speaker 1: Neo Sensory, and we have been on the market since
Speaker 1: March and we're now on risks all around the world.
Speaker 1: So people who are deaf, for have hearing loss of
Speaker 1: some degree where this and they are picking up on
Speaker 1: the auditory world through their skin. Now, the interesting part
Speaker 1: is this is exactly what the inner ear is doing.
Speaker 1: Your inner ear is just registering vibrations of your ear
Speaker 1: drum and it breaks sound up into from high to
Speaker 1: low frequency, and then it ships it off to the brain.
Speaker 1: And all we're doing is transferring the inner ear to
Speaker 1: to the wrist and it works. So that's the idea
Speaker 1: of sensory substitution. Is your um just getting the information
Speaker 1: there via a different route and the brain figures out
Speaker 1: what to do with it. And if this weren't amazing enough,
Speaker 1: there's this then this this other additional step, this idea
Speaker 1: of of plugging all new things into like new forms
Speaker 1: of sensory information, new even uh you know, not only
Speaker 1: limbs of replacement, but artificial addition. No limbs. You use
Speaker 1: the example of doctor Octopus from the spider Man comics. Um,
Speaker 1: can you tell us a little bit about how even
Speaker 1: like this nineteen sixties sci fi concept is not that
Speaker 1: far removed from our current understanding of the brain. Yeah, so, um,
Speaker 1: let me actually let me say two things. Actually, one
Speaker 1: is what we can do. So let me just separate
Speaker 1: out sensory information coming in and motor information going out.
Speaker 1: So sensory information coming in. One of the things we're
Speaker 1: doing with the with our wristband called buzz um is
Speaker 1: we can not only take in sound information for people
Speaker 1: who are deaf, but we could actually expand the sensory
Speaker 1: information that you would normally have. So, for example, with
Speaker 1: somebody who's not deaf, we feed in ultra violet or
Speaker 1: infrared or or things like that, where we're expanding senses
Speaker 1: that you already have. And then we're doing this other
Speaker 1: thing called sensory addition, where we're feeding in brand new
Speaker 1: senses that you've never had. So we can feed in
Speaker 1: any day to stream with this, like stock market data
Speaker 1: or Twitter data or factory information or anything at all.
Speaker 1: Feeding this in and as long as your brain can
Speaker 1: make correlations with what it's seeing or hearing around it.
Speaker 1: Then the brain can figure out how to utilize that information.
Speaker 1: So we actually just finished a big developer contest where
Speaker 1: people did all kinds of projects with you know, um
Speaker 1: monitoring air quality or monitoring you know, blood sugar and
Speaker 1: your bloodstream or um, um, many many different kinds of
Speaker 1: monitoring of feeling, electrical fields and so on. UM. So
Speaker 1: all this, by the way, if if anybody is interested,
Speaker 1: we have an open a p I and an s
Speaker 1: d K four buzz. You can get this on neo
Speaker 1: central dot com and pursue any kind of project you
Speaker 1: want this way. So we've had hundreds of people just
Speaker 1: making their own thing, which has been which has been
Speaker 1: very cool. Now to switch to the second thing about
Speaker 1: motor output. UM, yeah, it turns out that your brain
Speaker 1: UM is not pre programmed to drive your body, but
Speaker 1: instead can figure out whatever the affordances are of whatever
Speaker 1: is there. So just as an example, you know, one
Speaker 1: of the things I tell the story about this dog
Speaker 1: um that was born without fore limbs. It didn't have
Speaker 1: his front legs, and so it just she walks by petally.
Speaker 1: She walks on her back legs like a human, and
Speaker 1: presumably any dog could do this, but they're not sufficiently motivated,
Speaker 1: but so she just walks around her hind legs and um.
Speaker 1: What this illustrates is that dog brains are not pre
Speaker 1: programmed to drive dog bodies, but instead they figure out, Okay,
Speaker 1: here's what I can do. I need to get to
Speaker 1: my food, to my water, to my mother whatever. This
Speaker 1: is how I do it. And so um. Also, I,
Speaker 1: you know, tell the story of the guy who's the
Speaker 1: world's best archer. He has the world's record for best
Speaker 1: archery shot, and he doesn't have arms, so he does
Speaker 1: this with his legs. And it's just another illustration that
Speaker 1: the brain figures out whatever body it's in says okay,
Speaker 1: I figure how to drive this. Of course, we see
Speaker 1: this when people, for example, get an amputation. Let's say
Speaker 1: they lose an arm and a motorcycle accent or something.
Speaker 1: The map of their body in their brain readjust to say, okay,
Speaker 1: I see I've got a body without an arm, so
Speaker 1: I'm just gonna figure that out now. Okay. So, because
Speaker 1: it is not pre programmed, it's extremely flexible. Um, I
Speaker 1: think that we could actually build any kind of body
Speaker 1: we want. So UM, coming back to your question, I
Speaker 1: you know, mentioned about Doc Cock in the nineteen sixties,
Speaker 1: which debuted in Spider Man. This scientist who plugs in
Speaker 1: four robotic arms so that he can actually do extra
Speaker 1: things and poor beakers and so on, and he controls
Speaker 1: us with his brain. But then there's an explosion in
Speaker 1: his lab and he turns evil and he scales buildings
Speaker 1: and learns new forms of martial arts with with eight
Speaker 1: arms and so on, and um, Dr Octavia starts to
Speaker 1: go by Doc Cock anyway, Um, the exactly as you said,
Speaker 1: this is not as far off and weird as we
Speaker 1: used to think, because now what we're doing is with
Speaker 1: for example, patients who are paralyzed. Um, you can put
Speaker 1: electrodes into their motor cortex and they can learn to
Speaker 1: drive a robotic arm even though they are paralyzed. They
Speaker 1: drive the robotic arm with their thoughts, which sounds weird,
Speaker 1: but that's of course, how you drive your fleshy arm.
Speaker 1: You just you know, you think about it, you learn
Speaker 1: the you learn what the output signals are that make
Speaker 1: your arm respond. It's the same thing with the robotic arm,
Speaker 1: and you can do that. And there have been experiments
Speaker 1: with monkeys where they their bodies work fine. They're not paralyzed,
Speaker 1: but they can drive a third arm with you know,
Speaker 1: with their thoughts. So they're driving a robotic arm with
Speaker 1: their thoughts. There was an experiment done where a monkey
Speaker 1: um uses his motor cortex to make a robot walk.
Speaker 1: But the interesting part was the robot happened to be
Speaker 1: across the world. The monkey was in North Carolina and
Speaker 1: the robot was in Japan, and the signals from the
Speaker 1: monkey's brain were being sent over the internet and you
Speaker 1: can get the robot, you know, the monkey to control
Speaker 1: the robot just with the spikes in its motor cortex.
Speaker 1: And so, UM, I think it's going to be no
Speaker 1: time at all before we really to start controlling external
Speaker 1: devices with our thoughts. And one of the things, one
Speaker 1: of the frameworks that I build is this issue that
Speaker 1: what we think of as the self, what you think
Speaker 1: of as your body, just as a matter of control,
Speaker 1: what can you control with your body? And I think
Speaker 1: this is, by the way, why we understand our reflections
Speaker 1: in the mirror to be us, because you move and
Speaker 1: it moves, and so you're driving what you're seeing over there,
Speaker 1: so you think, oh, yeah, that's me over there. Um,
Speaker 1: But what this means is in you know, make up
Speaker 1: a number thirty five years when we are controlling a
Speaker 1: robot with our thoughts, it is essentially an extension of
Speaker 1: our body. What it means is that that will become us.
Speaker 1: It will be a part of of your body. All right,
Speaker 1: We're gonna take a quick break, but I'll be right
Speaker 1: back with David Eagleman. Thank alright, I'm back with David Eagleman.
Speaker 1: In the book, you talk about the live wired brain
Speaker 1: is um is being a place of competition, um based
Speaker 1: on the input that's coming in. And I was just
Speaker 1: really uh intrigued by this, uh, this new theory of
Speaker 1: dreaming that you discuss. So would you would you mind
Speaker 1: uh sharing that with our listeners. Yeah, um, yeah, this
Speaker 1: is something very cool that's come out of our studies
Speaker 1: of plasticity and UM here it is. It's that when
Speaker 1: any part of the brain goes unused, it gets taken over.
Speaker 1: And so for example, if you go blind, your systems
Speaker 1: for hearing and touch and all of that real estate
Speaker 1: will take over the part of the brain that we
Speaker 1: used to call the visual cortex. So the surprise in
Speaker 1: neuroscience has been how rapidly this happens um. What group
Speaker 1: found about thirteen years ago was that if you take
Speaker 1: sighted people and you blindfold them tightly and you stick
Speaker 1: them in a brain scanner, within about an hour, you
Speaker 1: can start seeing activity in the visual cortex just based
Speaker 1: on um hearing or touch. If you touch them on
Speaker 1: the hand or something, you start seeing activation in the
Speaker 1: visual cortex. Now, it's not because the neurons have had
Speaker 1: a chance to grow that fast from hearing and touch
Speaker 1: into the visual cortex. Instead, there's all kinds of cross
Speaker 1: wiring in the brain where those systems are already reaching
Speaker 1: over into the visual cortex. It's just that they're normally
Speaker 1: silenced and they're inhibited, so they don't get to do anything.
Speaker 1: But that inhibition starts wearing off very quickly. And so
Speaker 1: I was really shocked by the speed at which hearing
Speaker 1: and touch could take over. And so my student and
Speaker 1: I were talking about this one day, and what we
Speaker 1: realized is there's a very critical thing that happens because
Speaker 1: we live on a planet that rotates into darkness for
Speaker 1: half the time. You know, in the dark, you can
Speaker 1: still hear and touch and taste and smell and all
Speaker 1: that just fine, but you can't see, and of course
Speaker 1: I'm talking about evolutionary time, not recent electricity times. And so, um,
Speaker 1: what this means is that the visual cortex has always
Speaker 1: been in a big disadvantage when the planet rotates into darkness.
Speaker 1: And so what we realized is, wow, if it doesn't
Speaker 1: want to get taken over by the other senses, it
Speaker 1: has to have some way of defending its territory. And
Speaker 1: what we realized was that that's what dreams are. You
Speaker 1: have this very specific circuitry that starts in the midbrain
Speaker 1: and goes through a series of steps and just blasts
Speaker 1: activity into the visual cortex every night, about every ninety minutes.
Speaker 1: And and that's its only job. It's just blast activity
Speaker 1: in there. It's very specialized circuitry. It's very specific of
Speaker 1: the type of thing that, to the ananimous eye, is
Speaker 1: not accidental. And so and of course, because it's our
Speaker 1: visual cortex, we you know, we see and we think, oh,
Speaker 1: I'm having this full, rich visual experience. Um. And of
Speaker 1: course dream content might have to do with you know,
Speaker 1: it certainly has to do with what you've experienced during
Speaker 1: the day, in which synapses are still hot and so on.
Speaker 1: But but the point is that it's just blasting activity
Speaker 1: in there to defend the visual system against takeover. And
Speaker 1: so we've now done big studies on this. For example,
Speaker 1: where I'll just give you one thing that we just
Speaker 1: published recently where we compare twenty five different species of
Speaker 1: primates and we looked at how plastic they were, because
Speaker 1: across even the primate kingdom, we have this um you know,
Speaker 1: spectrum of how plastic you drop into the world and
Speaker 1: then how much rem sleep they get in other words,
Speaker 1: how much you know, rapid eye movement or or that
Speaker 1: dreams sleep, because this is when dreams happen. And it
Speaker 1: turns out that the more plastic you are as a species,
Speaker 1: the more dream sleep you have because you need to
Speaker 1: defend it more. As opposed to the other end of
Speaker 1: the spectrum. Let's say lemurs drop into the world and
Speaker 1: they're pretty much fully baked um and they have very
Speaker 1: short you know, adolescents time and walking time and weaning
Speaker 1: time and all that stuff. Um, they don't have much
Speaker 1: dream sleep because they don't need it because their brain
Speaker 1: is sort of baked into place. And by the way,
Speaker 1: I'll just mention one other thing because people sometimes ask
Speaker 1: about this, which is um you know, they say, do
Speaker 1: blind people dream. Yes, blind people have dreams where activity
Speaker 1: is getting shot into their occipital lobe at the back
Speaker 1: of their head. But because they are blind, they don't
Speaker 1: experience that is vision. Instead, they experience it is hearing
Speaker 1: and touch. So blind people's dreams are all about you know,
Speaker 1: weird bizarre things just like ours, but it's not involving vision.
Speaker 1: It's you know, I'm I'm walking around my house and
Speaker 1: all my furniture is rearranged, and I'm feeling stuff, and
Speaker 1: then there's a bear and I'm feeling the bear and
Speaker 1: all that kind of stuff. So um, But it's exactly
Speaker 1: the same circuitry that they have, because this is a
Speaker 1: very fundamental circuitry that has burned into the system, and
Speaker 1: it doesn't care whether your eyes are working or not,
Speaker 1: because it's it's more, it's deeper than that, and has
Speaker 1: working on this has has changed the way you reflect
Speaker 1: on your own dreams at all. You know, I've always
Speaker 1: actually felt that dreams are not terribly meaningful like my
Speaker 1: own you know, I wake up. I've always described this
Speaker 1: as sort of sticking your head in the night blender
Speaker 1: each night. I kind of hate dreams, um, But now
Speaker 1: I have a deeper appreciation for why I'm going through
Speaker 1: that night blender, because um, if not, I would wake
Speaker 1: up in my visual system would be really disadvantaged. It
Speaker 1: would be taken over in large part by hearing it
Speaker 1: by touch. Especially in the later portions of the book,
Speaker 1: you you get into two memories and and even identity,
Speaker 1: and there's there's a lot that really seems to resonate
Speaker 1: with the state of the world right now. How do
Speaker 1: you feel this book speaks to the reader? Yeah, I
Speaker 1: think there. I think there are many ways. Um, I'll
Speaker 1: mention too. One is actually, let me start with this
Speaker 1: optimistic one, which is um as lousy as has been
Speaker 1: for everybody. And you know, this is a year where
Speaker 1: there's serious spikes for everybody in stress, anxiety, depression. It's
Speaker 1: just there's all kinds of bad stuff. But I will
Speaker 1: mention one tiny silver lining of this is that from
Speaker 1: the point of view of brain plasticity, we've all been
Speaker 1: kicked off of our hamster wheels and we're all being
Speaker 1: forced to rethink many things that we never thought about before.
Speaker 1: So I mentioned before that our brain is locked in
Speaker 1: silence and darkness, is trying to make an internal model
Speaker 1: of the world out there and we all pretty much
Speaker 1: had that. We thought, Okay, I get how the world works,
Speaker 1: I get how things operate, how people respond, how to
Speaker 1: get toilet paper, how to get food in my fridge,
Speaker 1: stuff like that, and all of a sudden everything changed.
Speaker 1: And from the point of view of brain plasticity, this
Speaker 1: is actually really useful. It has forced a kind of creativity,
Speaker 1: an unwanted one for sure, but it's forced kind of
Speaker 1: creativity where you're having to rethink everything. We're having to
Speaker 1: understand many things in more depth that we never thought
Speaker 1: twice about before. And um, it turns out when we
Speaker 1: look at things like you know, dementia, what happens is
Speaker 1: people retire and they stop challenging themselves, and their brains
Speaker 1: end up in a worse and worse state. And the
Speaker 1: people who retire and end up fine and much better
Speaker 1: off are those who keep challenging themselves with novel things.
Speaker 1: And that includes even basic things like just you know,
Speaker 1: making sure you're not just sitting around watching TV but instead,
Speaker 1: you know, taking on new sorts of challenges and tasks
Speaker 1: and keeping an active social life and stuff like that.
Speaker 1: So anyway, this is what's happening to all of us.
Speaker 1: And I have a slight suspicion this will be hard
Speaker 1: to prove, but just an intuition that we may find
Speaker 1: a slight dip in dementia um in in the coming
Speaker 1: years for people who have been you have lived through
Speaker 1: this early twenties um simply because they've really gotten a
Speaker 1: chance to build all kinds of new roadways in their brain,
Speaker 1: whereas they might not have done that as as adults.
Speaker 1: The second thing that I'll mention as far as is
Speaker 1: one of the things that my lab has been studying
Speaker 1: for a very long time is social neuroscience, which is
Speaker 1: this issue of how there's a lot of the brain
Speaker 1: circuitry that's devoted to other people. In other words, you know,
Speaker 1: we normally look at the brain and we think already
Speaker 1: there's hearing, the touchows, vision, and so on, But in fact,
Speaker 1: a lot of your circuitry has to do with modeling
Speaker 1: other people. And you might know a thousand people and
Speaker 1: you've actually got circuitry devoted to every one of them,
Speaker 1: and circuitry devoted to okay, who knows who and have
Speaker 1: they dated before and blah blah blah. I mean, it's
Speaker 1: it's a very sophiskated social system that we're carrying around.
Speaker 1: And so one of the things that got me interested
Speaker 1: a long time ago, and we've published and written on
Speaker 1: this for years, but suddenly it really is important. Is
Speaker 1: this issue about in groups and now groups. And it
Speaker 1: turns out that, um, we here, I'll just tell you
Speaker 1: really quickly about a study we did. We we take
Speaker 1: people into the brain scanner and we show them six
Speaker 1: hands on a screen and the computer goes around and
Speaker 1: selects one of the hands at random, and then you
Speaker 1: see that hand get stabbed with a syringe needle. And
Speaker 1: what happens is you really cringe when you see that.
Speaker 1: It's it's awful to see somebody's hand get stablished with
Speaker 1: a needle, and that activates this network in your brain
Speaker 1: that summarized is the pain matrix, which is to say,
Speaker 1: you're you're such a feeling the pain of that. Um
Speaker 1: that is the neural basis of empathy. You care about
Speaker 1: somebody else because you're immediately running a simulation of what
Speaker 1: if that was my hand, even though it's not physically
Speaker 1: your hand getting touched. But what we do then is
Speaker 1: we put a one word label on each of these hands. Christian, Jewish, Muslim, Atheist,
Speaker 1: Hindu scientologist and then the computer goes around and picks
Speaker 1: a hand, and see the hand gets stabbing. The question
Speaker 1: is do you care? Does your brain care as much
Speaker 1: if it's someone in your outgroup versus a member of
Speaker 1: your in group, And that's exactly what happens. If it's
Speaker 1: a member of your in group, you have a much
Speaker 1: bigger response, and if it's a member of your outgroup,
Speaker 1: your brain doesn't really care that much. And it turns
Speaker 1: out that we do all kinds of versions of this.
Speaker 1: Just as one example, we then say, okay, the year
Speaker 1: is twenty five, and these three religions have teamed up
Speaker 1: against these three religions, and now your two allies you
Speaker 1: care slightly more than you did a minute ago, just
Speaker 1: because you're told in this one sense thing that that
Speaker 1: they're allied with you, and the others are still clearly
Speaker 1: in your out groups, so your brain just doesn't care
Speaker 1: as much. And by the way, just as a side note,
Speaker 1: atheists have exactly the same thing about seeing atheist hands
Speaker 1: gets up. So it's not an indictment of religion. It's
Speaker 1: just an issue about in groups and out groups who
Speaker 1: you feel like, you know what your labels are. Um,
Speaker 1: so we've done a lot of work on that, if
Speaker 1: anyone's interested. I wrote in a uh an article in
Speaker 1: The Economist last year called does your brain care about
Speaker 1: other people? It depends? Um. But all of a sudden, unfortunately,
Speaker 1: all of this stuff is more relevant because society is
Speaker 1: really finding ways to divide themselves up with in groups
Speaker 1: and now groups. Um. You know, some people blame social media.
Speaker 1: The fact is, you know, I'm a real student of history,
Speaker 1: and the fact is that we've had this kind of
Speaker 1: stuff happened all the time, with the Chinese Cultural Revolution
Speaker 1: or the Russian Revolution or you know, or what happened
Speaker 1: to Nazi Germany or we we've we've seen this stuff
Speaker 1: lots of times before the Internet. So it's not like
Speaker 1: the Internet is this the single thing to blame here.
Speaker 1: This is just human nature. Um. So anyway, this is
Speaker 1: what I think is relevant. Alright, We're gonna take one
Speaker 1: more break, but I'll be right back with David Eagelman.
Speaker 1: Thank alright, I'm back with David Eagleman. So well, let's
Speaker 1: let's take a brief journey into the future here again
Speaker 1: coming back to the idea of neural technology in the
Speaker 1: future allowing us to augment our senses our bodies. If you,
Speaker 1: let's say you were to enter a state of suspended
Speaker 1: animation and emerge a hundred years from now, how much
Speaker 1: of the human sensory experience will have changed and how
Speaker 1: different How difficult do you think it would be for
Speaker 1: a twenty second century human to relate these senses to you? Yeah,
Speaker 1: I think I think this is a key issue, which
Speaker 1: is to say, we have certain what are called quality
Speaker 1: of which is, you know, our internal experience of something
Speaker 1: like vision and hearing and so on. And you know,
Speaker 1: obviously the stuff is completely made up by our brains
Speaker 1: in the sense that just an example, colors don't exist
Speaker 1: in the world. All you have is different wavelength of
Speaker 1: electromagnetic radiation. But your brain comes up with a way
Speaker 1: of summarizing things quickly, so it can see the ripe
Speaker 1: fruit against the green leaves. It says, okay, I'm gonna
Speaker 1: call that red and that green perfect um, even though
Speaker 1: that doesn't exist. So we have this internal experience of
Speaker 1: the world. And of course, you know, sound also doesn't
Speaker 1: exist as such, You've just got air compression waves, but
Speaker 1: we turn it into you know, beautiful voices in music
Speaker 1: and so on. Um, okay, but here's the thing, it's
Speaker 1: because your brain has lots of experience with this that
Speaker 1: it eventually turns it into this direct perceptual experience. And
Speaker 1: so the question is, now, if you've fed in a
Speaker 1: new kind of data stream through the Neo centry buzz,
Speaker 1: for example, the wristband, if you fed in a completely
Speaker 1: new kind of thing, would you come to have a
Speaker 1: direct perceptual experience of it? And our data right now
Speaker 1: suggests yes, that that you would. And the thing that's
Speaker 1: so weird about this is there's actually no way to
Speaker 1: describe it to somebody who has not had that experience.
Speaker 1: So imagine that you had a friend who is color
Speaker 1: blind and you tried to explain orange to your friend.
Speaker 1: There's no way that she would understand. She could eventually
Speaker 1: pretend and say, okay, rab' just quit talking and I'm
Speaker 1: gonna pretend to understand, but she wouldn't ever understand orange.
Speaker 1: This why because you have to experience it to get it.
Speaker 1: And so um, and you know, if you have a
Speaker 1: blind friend, try to explain what vision is your friends,
Speaker 1: I don't understand. You're you're trying to You're you're capturing
Speaker 1: fote that you're capturing millions of photons every second from
Speaker 1: across great distances, and there's just no way that they
Speaker 1: can understand what that's like. And so the same thing applies,
Speaker 1: I think for twenty second century people who are getting
Speaker 1: direct data streams fed to their brain of stock market
Speaker 1: or microwave data information or um, you know, gamma ray
Speaker 1: information or whatever the thing is that they're feeding in.
Speaker 1: You're like the person who doesn't understand what orange is
Speaker 1: or what vision is to them. And they can try
Speaker 1: really hard to explain to you, and you can even
Speaker 1: pretend at some point they understand, but you just won't.
Speaker 1: And um, So I think we're on the verge of
Speaker 1: a really interesting moment in history where where we're gonna
Speaker 1: essentially start speciating, as in, people are going to have
Speaker 1: such different experiences that they won't be able to relate
Speaker 1: them to each other. Now, let me just say, there's
Speaker 1: a sense in which this is no different from what
Speaker 1: we've always had in the sense that you know, you
Speaker 1: grew up in your hometown and had your experience. I
Speaker 1: grew up my hometown and had my experiences. And there's
Speaker 1: a sense in which brains are pretty different anyway. Um,
Speaker 1: but this is just going to be more of that
Speaker 1: where I'm you know, plugged directly into Twitter, and you're
Speaker 1: plugged directly into infrared information and we just can't quite
Speaker 1: get what the other person is experiencing. So you worked
Speaker 1: as a science advisor on HBO's West World, that's right,
Speaker 1: that's right, um. And you know, one of the things
Speaker 1: that I've found in advising for television in general is
Speaker 1: that there are all these topics that I and my
Speaker 1: colleagues have debated for years, were you know, for example,
Speaker 1: the question of could robot become conscious and what would
Speaker 1: that mean? And would they have free will? And so on? Um,
Speaker 1: and you know, we write all these academic papers on it.
Speaker 1: But it's it's such a cool opportunity to get these
Speaker 1: questions to, you know, into the public square with fiction.
Speaker 1: And so something like west World is tremendously successful into
Speaker 1: getting people to think about these sorts of questions. And
Speaker 1: one of the things that I did as scientific advisor was, UM,
Speaker 1: got our vest or neosensory vest into the show. So
Speaker 1: you know, it was I don't know if anybody out
Speaker 1: there I saw this episode during season two, but um,
Speaker 1: these military contractors drop into west World to take care
Speaker 1: of the hosts. The bad robots and they are feeling
Speaker 1: on their vest their location of the robots. So, oh,
Speaker 1: there's location over there there, sorry, there's a there's robot
Speaker 1: over there. There's one over there, and then they can
Speaker 1: shoot them accordingly. But we've actually used exactly that For
Speaker 1: people who are blind, we've used the same idea, which
Speaker 1: is a wearing the vest and they're feeling where people
Speaker 1: are around them and oh, there's somebody coming up behind me,
Speaker 1: there's someone over here on my left, and so on,
Speaker 1: and then we can add navigation directions on top of that.
Speaker 1: Um you know, so it buzzes okay, go four, oh go,
Speaker 1: the left now goes straight and so on. Um. So yeah,
Speaker 1: that was a very cool, very cool opportunity that we
Speaker 1: had to get our technology into this futuristic show. I
Speaker 1: love that sequence in the show because I felt like
Speaker 1: like a lesser show would have just copied Aliens and
Speaker 1: just had you know, blips on a map. Uh and
Speaker 1: but this felt this, this felt thoroughly science fictional in nature,
Speaker 1: you know. I mean, but then a golf course is
Speaker 1: using actual technology that we're developing today exactly right now.
Speaker 1: You mentioned West World bringing scientific topics or just topics
Speaker 1: concerning things like consciousness out into the public square. The
Speaker 1: first season at least discussed Julian james b cameral mind
Speaker 1: hypothesis that brought that up a little bit. And I
Speaker 1: know you wrote about this a little bit in incognito,
Speaker 1: but what are your general thoughts on this hypothesis. You know,
Speaker 1: what's interesting is that no one actually knows if it's
Speaker 1: correct or not correct. So what Julian James proposed is
Speaker 1: that it may be that you essentially have two sides
Speaker 1: to the brain, the left and the right side, literally
Speaker 1: the two hemispheres, and that those used to be more
Speaker 1: separate and um, so it was as though people were
Speaker 1: hearing a voice from somebody else. And what he argues
Speaker 1: is that if you look at ancient literature, like ancient
Speaker 1: Greek literature and so on, there's always this thing about
Speaker 1: hearing a voice from God and so on. Um. And
Speaker 1: the argument is that very recently the left and right
Speaker 1: hemisphere started connecting in a deeper way, um, and so
Speaker 1: there was this super highway of fibers that goes back
Speaker 1: and forth between them. And so what we have now
Speaker 1: is a unified consciousness instead of two separate voices going
Speaker 1: on in our heads. As I said, nobody really knows
Speaker 1: that this is right or not, because there's no simple
Speaker 1: way to test this directly. What I argued, an incognito though,
Speaker 1: is essentially a a distant cousin of that, which is
Speaker 1: that what is absolutely clear is that we are not
Speaker 1: a single thing. So we think of ourselves as individuals,
Speaker 1: meaning not divisible into different parts. But but in fact
Speaker 1: who you are is a collection of different neural networks
Speaker 1: that all have different drives. And this is why we
Speaker 1: can are you with ourselves and custed ourselves in contract
Speaker 1: with ourselves, and canjole ourselves who's talking with whom? Here?
Speaker 1: It's all us, but it's different parts of us. So
Speaker 1: this is why if I take some warm chocolate chip
Speaker 1: cookies out of the oven and put them in front
Speaker 1: of you, part of your brain says, don't eat it,
Speaker 1: you'll get fat, and party brain says that looks like
Speaker 1: a high energy sort. You know, I totally want to
Speaker 1: eat those cookies, And part of your brain says, okay,
Speaker 1: how about I eat the cookies, but I'll go to
Speaker 1: the gym tonight or whatever. Like everything that we do
Speaker 1: in our lives, we have arguments with ourselves about Okay,
Speaker 1: what should I do here? Part of me want to eat,
Speaker 1: this part of me doesn't want to And so what's
Speaker 1: going on? There are all the different voices, the different
Speaker 1: political parties of this neural parliament that we have running
Speaker 1: under the hood. And this is the framework that I
Speaker 1: built in in incognito, is that we've got this parliament
Speaker 1: and the way you go just depends on the majority
Speaker 1: vote in any given moment, and so you're not one thing,
Speaker 1: You're a collection of voters. All right. I have one
Speaker 1: one last question for you. Um, if if you could
Speaker 1: go back in time and serve as a sign advisor
Speaker 1: on any past science fiction film, what would it be.
Speaker 1: What would you most like to go back and tweak
Speaker 1: or correct or make a little more neuroscientifically interesting? Oh gosh,
Speaker 1: I'd have to think about that off the top of
Speaker 1: my head. Um. Something like the Matrix is terrific because
Speaker 1: that's an example actually of of a piece of fiction
Speaker 1: that got everybody talking about this issue of how do
Speaker 1: you know? Like you know, Decartes said, how would I know?
Speaker 1: If I'm a brain in a vat um and and
Speaker 1: I just think that I'm feeling and hearing and seeing
Speaker 1: these different things and that that got upgraded that question
Speaker 1: by philosophers um at different stages in history. But but
Speaker 1: essentially that's the question is how do I how do
Speaker 1: I know if there's a bunch of scientists that are
Speaker 1: zapping my brain with electrodes that are making me feel
Speaker 1: that I'm talking with you on zoom and the weather
Speaker 1: is nice outside and so on. But then the matrix,
Speaker 1: I think single handedly upgraded that question too. How do
Speaker 1: I know if I'm in the matrix if I am
Speaker 1: a simulation? And and as things have gone on, especially
Speaker 1: in the last I don't know, ten years in Silicon Valley,
Speaker 1: it feels like people talk about that question more and
Speaker 1: more seriously all the time because you look at our
Speaker 1: computational capacity and you think, well, gosh, it's it's really
Speaker 1: not that hard to make super sophisticated VR in So
Speaker 1: what's this gonna look like in twenty one twenty I mean,
Speaker 1: you can make something that is absolutely convincing. I mean,
Speaker 1: forget it, you can do that. It's just like a
Speaker 1: convincing So the question is how would you know if
Speaker 1: you exist in a simulation or not? And what they
Speaker 1: cart concluded, by the way, is that there is no
Speaker 1: way for him to know um, and this is what
Speaker 1: led to his very famous declaration, japons don suite. I
Speaker 1: think therefore I am um because what he meant by
Speaker 1: that is, look, I don't know if I'm in a simulation.
Speaker 1: But all I can tell you is that there's somebody
Speaker 1: thinking about this question. So I exist, whoever, whoever, whatever
Speaker 1: situation I'm actually and it doesn't matter. There's some eye
Speaker 1: that exists. And that was actually a quite important move
Speaker 1: in philosophy. But the point is, we have absolutely no
Speaker 1: way of knowing if we are in a simulation or not.
Speaker 1: And uh, we don't even have any good hypotheses about
Speaker 1: how we would be able to find that out. And
Speaker 1: by the way, it might not matter. I mean, you know,
Speaker 1: if I told you with certainty that we are or
Speaker 1: are not, it would it might not change anything about
Speaker 1: what you're doing. Um So, But so I would love
Speaker 1: to have been involved in in that movie and and
Speaker 1: add in just a few neuroscience e uh twists and
Speaker 1: sentences and questions there. Awesome, David, thanks again for chatting
Speaker 1: with me today. Great, thank you, Robert. This is blessed
Speaker 1: all right. So there you have it again. The book
Speaker 1: is Live Wired the inside Story of the Ever Changing
Speaker 1: Brain by David Eagleman. It's out now and if you
Speaker 1: want to check out Neosensory you can just go to
Speaker 1: neosensory dot com. If you'd like to listen to other
Speaker 1: episodes of Stuff to Blow Your Mind, you can find
Speaker 1: us where every at your podcast and wherever that happens
Speaker 1: to be. We just asked that you rate, review and subscribe.
Speaker 1: Thanks as always to Seth Nicholas Johnson for his recording
Speaker 1: skills and editing skills and bringing all this together especially
Speaker 1: short to turn around today. And if you would like
Speaker 1: to email us about this interview, about this episode, or
Speaker 1: about forthcoming episodes or past episodes, you can do so
Speaker 1: at contact at stuff to Blow your Mind dot com.
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