September 11, 2021 • 41 mins
What does our growing understanding of neuroplasticity reveal about our brains and the future of technology? In this classic episode of Stuff to Blow Your Mind, Robert chats with neuroscientist David Eagleman about his new book “Livewired: The Inside Story of the Ever-Changing Brain.” (originally published 9/29/2020)
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Speaker 1 (00:05):
Hey, you welcome to Stuff to blow your mind. This
is Robert Lamb and I'm Joe McCormick, and it's Saturday
time for a Vault episode. This one originally aired September
twenty nine. Rob, this was the interview that you did
with the neuroscientist David Eagleman. Yeah, this is a lot
of fun gets that he gets into some really cool ideas.
Here a possible explanation for what dreams are for? And uh,
(00:29):
one of my favorite parts, how in which ways? Uh?
Is the human brain like a Mr Potato Is a
Mr Potato different from Mr potato Head? Well it's Mr
potato Head. Yes, Uh oh, I guess actually it's not
Mr It's just potato Head now right, Well, I think
now there is still a Mr. Potato Head, but there's
also a broader potato head concept. Okay, yeah, I haven't
(00:50):
followed all the potato head news, but I've I've caught
wind of some of the like the faux outrage over
over some of it. So at any rate, it's a
eagle and uses the potato head um as a wonderful
metaphor for exactly how our brain works when you plug
different sensory inputs into it, so I highly recommend it.
It's a great, great, really enjoyable interview. I enjoyed it.
(01:12):
I think folks will enjoy it as well. Welcome to
Stuff to Blow Your Mind, production of My Heart Radio. Hey,
welcome to Stuff to Blow Your Mind. My name is
Robert Lamb. Joe is away from work. He's realigning his
(01:33):
gray matter at the moment, so it's just me today,
but I'll be joined by neuroscientist, author, and science communicator
David Eagleman about his new book Live Wired, The Inside
Story of the Ever Changing Brain. Now we've mentioned David
Eagelman on the show many times before. He's an adjunct
professor at Stanford University and his CEO of Neo Sensory,
(01:55):
a company that develops devices for sensory substitution. You may
also know him from his previous books about the human brain,
his TV series The Brain with David Eagleman, and his
role as a scientific advisor on HBO's Westworld and the
TNT series Perception. I'm recording this on a Monday, and
I actually read Live Wired over the weekend. It's a
highly addictive read and one that I think our listeners
(02:17):
will will really enjoy. David does an amazing job breaking
down the inner workings of the brain via relatable pop
culture and historical metaphorth everything from the colonization of the
America's to Mr Potato Head and Ellen Ripley from Aliens.
It's published by Pantheon Books and you can currently grab
it as a hardcover, an e book, or an audio book.
(02:38):
And the fun thing is that that David reads the
audio book. It's always great when you when you get
that with an audio book. So, without without any further ado,
let's jump right in. David Eagleman, thanks for joining me today.
Great to be here, Robert. First of all, I have
I just have to say that this book was such
an engaging read. I actually read it all over the weekend,
(02:59):
and while I was familiar with some of the findings
and technologies discussed, there was plenty I hadn't been exposed
to yet, and it was all delivered in such a
fashion that it all ended up feeling like, you know,
it's kind of like a revelation, um, and I feel
like that revelation is really well summarized in the title
of the book, Live Wired. If you would, could you
summarize the basic difference between the idea of the live
(03:22):
wired understanding of our brain as opposed to previous notions
of how the brain worked. Yeah, I mean the whole
The whole thing is that when you first pick up
a neuroscience textbook as a young person, you see a
picture of the brain and it says this parts or vision,
this parts are hearing, the parts are touch, and so on.
But in fact, um, I guess what I've spent the
last twenty years, you know, in my laboratory really understanding
(03:46):
the lesson of is that the brain is a is
a dynamic system that's constantly moving around. And so for example,
if you go blind, the part that we would have
called your visual system gets taken over by hearing and touch.
If you lose an arm, the part of your body
map that has an arm gets taken over by neighboring
areas and so on. The whole thing is this incredibly
(04:06):
dynamic system. It's not like anything that we know how
to build. Um. You know, here in Silicon Valley where
I live, everything is about hardware and software, and engineers
are praised for building an efficient system where you've got
these two layers and that's it. Um. But what's happening
in our skulls is an entirely different kind of technology,
(04:26):
and so I in the book, I ended up coining
a new term for this, live wired or live ware.
And the idea with live ware is that every moment
of your life, this is reconfiguring itself. So you've got
eighty six billion neurons, these are the cell types of
the brain. You've got about point to quadrillion connections, and
(04:49):
every moment in your life, these things are changing their
strength of connection. They're unplugging, they're replugging elsewhere, they're seeking around.
What you have are these dense jungles. And you know,
this level of complexity is something that bankrupts our language.
We don't have any way of talking about point two
quadrillion connections moving and changing. But everything in your life,
(05:10):
every experience that you have um changes who you are.
When you learn, for example, that my name is David,
there's a physical change in the structure of your brain.
And that's what it means for you to then remember,
you know, two months later, who's the guy you had
on your podcast David. You know, it's like it's it's
this constantly changing system and it's UM unlike anything that
(05:31):
we know how to build at the moment. So, um,
you know, as you as you saw in the book.
I tell these different stories just by way of introduction
that are so fascinating, Like you can take out half
the brain in a child. For example, when children have
this really bad type of epilepsy, there's a surgery that
they go through. Half the brain is removed, and they're
(05:53):
just fine cognitively, they're totally fine because the rest of
their brain, the other half says, okay, I'm gonna read
are the functions that are that went missing from there.
Sometimes a child is born with only half a brain,
you know, and things just get get rewired so that
it all is there and we can't you know, you
can't do this with your cell phone or your computer.
(06:15):
You can't take out half the circuitry and expect it
to still function. But it works just fine, especially with
a young brain. Now, with all of this in mind,
into this live wired understanding of the brain in mind, um,
I thought we might back up to a very basic question,
uh that sometimes I guess we don't think about because
we're I mean, we were trapped in the brain. We
(06:36):
can't see the forest for the trees. But what what
does the brain do? So the brain is locked in
silence and darkness inside the vault of your skull, and
all it's trying to do is make a model of
the world, as in, I've got all this incoming data.
And by the way, the data that comes into the
brain is just spikes, just little electrical spikes in these neurons.
(06:59):
It doesn't know that these spikes represent photons, and these
spikes represent air compression waves, and these spikes represent mixtures
of molecules hitting a membrane and so on. All it
knows is I've got data coming in as zeroes and
ones and um and it knows that it can control
a body. And so it's job is to figure out,
all right, how do I control the body, how does
(07:20):
that change the spikes coming in? And how do I
make a model of the world. And this is an
extraordinary technology that we have carrying around on our shoulders.
Um As I said, we we don't know how to
build technology like this, and we're just scratching the surface
of even trying to figure this out. But that's what
the brain is doing, locked in its in its vault,
(07:40):
is figuring out, okay, how do I understand the world,
and and it's really extraordinarily good at at extracting patterns
and eventually making predictions. And um, yeah, that is that
is the main job that is trying to accomplish. Now,
the big part of the book deals with how our senses,
uh you know, speak to the brain and how the
rain works around limitations uh, such as they are the
(08:03):
ones you mentioned with the half of the brain being
missing at etcetera. And also uh you know, relating limbs
uh and uh and I love how you use these
various metaphors to explain that to the reader. Would you
mind uh explaining to our listeners how our brains are
like Mr potato head. Yeah, so this is something that
struck me many years ago where I realized that, so
(08:23):
we've got all these sensors like our eyes and our
ears and our nose and our fingertips, all these things
were used to and so we just sort of think
of these as fundamental. But but when you look across
the animal kingdom, what you find are all these other
weird kinds of sensors, things that you could take in
like snakes taken infrared information, honeybees taken ultra violet when
(08:44):
you look at something like the black ghost knifefish, it
has electro receptors where it's pulling in information about perturbations
and electrical fields. UM. Lots of birds and cows and
insects have magneto reception where they are picking up on
the magnet field of the planet and they're navigating that
way and so on. And what I realized is Mother
(09:04):
Nature doesn't actually have to recreate the brain every time
she does this. Instead, the principles of brain operation, she's
figured that out at the beginning, and then she can
just plug in anything she wants in terms of what
is the information that would be useful to sense. And
that's why I suggested this potato head model of how
(09:25):
to think about this, which is to say, you just
take any sensors and you stick it in and it's
good to go. The brain figures out, Okay, I've got
this kind of spikes coming in UM, and it seems
to correlate with this other sense, and it seems to
allow me to find food or avoid predators or whatever.
And so it just figures out what to do with
that information. And so this is a very new kind
(09:46):
of way to think about the brain. It's essentially understanding
the brain as a general purpose compute device. You feed
in whatever kind of data stream you want, and it's
and it's good to go. And this, you know, explains
a lot of what happens evolutionarily with janet x. It
just what it allows mother nature to do is just
tweak around with the genetics to make new kinds of sensors.
(10:08):
But one of the really amazing things you discussed in
this is that is that you can plug an eye
into an ear hole or an ear into an eye
hole on the Mr Potato head of our of our brain,
and the brain will roll with the data that that's
exactly right. And so this is an area called sensory substitution,
which is to say, you can feed information into the
(10:28):
brain via an unusual channel. And so something I started
in my lab about ten years ago was seeing if
we could build sensory substitution for people who are deaf.
So what we do. We started by building this as
a vest with vibratory motors in it. So you've got
a whole bunch of little buzzers like the buzzer in
your cell phone, and um, it captures sound and turns
(10:52):
out into patterns of vibration on the torso. And it
turns out that that worked really well. We could get
people who are profoundly deaf to start understanding what is
happening in the auditory world, just predicated on this spatio
temporal pattern of vibrations on their skin. And the reason
it worked is because it doesn't matter how the information
(11:12):
gets to the brain. As long as it gets there,
the brain will establish the correlations and figure out what
to do with it. So, as an example, if you see,
you know, the dog's mouth moving and you feel the
buzzing on your skin, you know, your brain puts that
together really easily. Or you know, you see somebody speaking,
or or we train people by showing a word and
you you know, you feel the word on the vest
and you start understanding what's going on. So what we
(11:34):
did then is we shrunk it down to the size
of a wrist band. And because you and I are
on video, Robert, you can see the wristband that I'm
wearing right now. It's you know, it looks about the
size of a fitbit, and it has very sophisticated computation
in here where it's capturing sound and turning that into
patterns vibration around the skin of the wrist and um.
(11:54):
So what we've been doing is we uh this Actually
now I spun a company out of my lab called
Neo Sensory, and we have been on the market since
March and we're now on risks all around the world.
So people who are deaf, for have hearing loss of
some degree where this and they are picking up on
the auditory world through their skin. Now, the interesting part
(12:17):
is this is exactly what the inner ear is doing.
Your inner ear is just registering vibrations of your ear
drum and it breaks sound up into from high to
low frequency, and then it ships it off to the brain.
And all we're doing is transferring the inner ear to
to the wrist and it works. So that's the idea
of sensory substitution. Is your um just getting the information
(12:40):
there via a different route and the brain figures out
what to do with it. And if this weren't amazing enough,
there's this then this this other additional step, this idea
of of plugging all new things into like new forms
of sensory information, new even uh you know, not only
limbs of replacement, but artificial addition. No limbs. You use
(13:00):
the example of doctor Octopus from the spider Man comics. Um,
can you tell us a little bit about how even
like this nineteen sixties sci fi concept is not that
far removed from our current understanding of the brain. Yeah, so, um,
let me actually let me say two things. Actually, one
is what we can do. So let me just separate
(13:22):
out sensory information coming in and motor information going out.
So sensory information coming in. One of the things we're
doing with the with our wristband called buzz um is
we can not only take in sound information for people
who are deaf, but we could actually expand the sensory
information that you would normally have. So, for example, with
somebody who's not deaf, we feed in ultra violet or
(13:45):
infrared or or things like that, where we're expanding senses
that you already have. And then we're doing this other
thing called sensory addition, where we're feeding in brand new
senses that you've never had. So we can feed in
any day to stream with this, like stock market data
or Twitter data or factory information or anything at all.
Feeding this in and as long as your brain can
(14:05):
make correlations with what it's seeing or hearing around it.
Then the brain can figure out how to utilize that information.
So we actually just finished a big developer contest where
people did all kinds of projects with you know, um
monitoring air quality or monitoring you know, blood sugar and
your bloodstream or um, um, many many different kinds of
(14:27):
monitoring of feeling, electrical fields and so on. UM. So
all this, by the way, if if anybody is interested,
we have an open a p I and an s
d K four buzz. You can get this on neo
central dot com and pursue any kind of project you
want this way. So we've had hundreds of people just
making their own thing, which has been which has been
very cool. Now to switch to the second thing about
(14:48):
motor output. UM, yeah, it turns out that your brain
UM is not pre programmed to drive your body, but
instead can figure out whatever the affordances are of whatever
is there. So just as an example, you know, one
of the things I tell the story about this dog
um that was born without fore limbs. It didn't have
(15:09):
his front legs, and so it just she walks by petally.
She walks on her back legs like a human, and
presumably any dog could do this, but they're not sufficiently motivated,
but so she just walks around her hind legs and um.
What this illustrates is that dog brains are not pre
programmed to drive dog bodies, but instead they figure out, Okay,
here's what I can do. I need to get to
my food, to my water, to my mother whatever. This
(15:30):
is how I do it. And so um. Also, I,
you know, tell the story of the guy who's the
world's best archer. He has the world's record for best
archery shot, and he doesn't have arms, so he does
this with his legs. And it's just another illustration that
the brain figures out whatever body it's in says okay,
I figure how to drive this. Of course, we see
this when people, for example, get an amputation. Let's say
(15:53):
they lose an arm and a motorcycle accent or something.
The map of their body in their brain readjust to say, okay,
I see I've got a body without an arm, so
I'm just gonna figure that out now. Okay. So, because
it is not pre programmed, it's extremely flexible. Um, I
(16:14):
think that we could actually build any kind of body
we want. So UM, coming back to your question, I
you know, mentioned about Doc Cock in the nineteen sixties,
which debuted in Spider Man. This scientist who plugs in
four robotic arms so that he can actually do extra
things and poor beakers and so on, and he controls
(16:34):
us with his brain. But then there's an explosion in
his lab and he turns evil and he scales buildings
and learns new forms of martial arts with with eight
arms and so on, and um, Dr Octavia starts to
go by Doc Cock anyway, Um, the exactly as you said,
this is not as far off and weird as we
used to think, because now what we're doing is with
for example, patients who are paralyzed. Um, you can put
(16:58):
electrodes into their motor cortex and they can learn to
drive a robotic arm even though they are paralyzed. They
drive the robotic arm with their thoughts, which sounds weird,
but that's of course, how you drive your fleshy arm.
You just you know, you think about it, you learn
the you learn what the output signals are that make
your arm respond. It's the same thing with the robotic arm,
and you can do that. And there have been experiments
(17:20):
with monkeys where they their bodies work fine. They're not paralyzed,
but they can drive a third arm with you know,
with their thoughts. So they're driving a robotic arm with
their thoughts. There was an experiment done where a monkey
um uses his motor cortex to make a robot walk.
But the interesting part was the robot happened to be
(17:40):
across the world. The monkey was in North Carolina and
the robot was in Japan, and the signals from the
monkey's brain were being sent over the internet and you
can get the robot, you know, the monkey to control
the robot just with the spikes in its motor cortex.
And so, UM, I think it's going to be no
time at all before we really to start controlling external
(18:02):
devices with our thoughts. And one of the things, one
of the frameworks that I build is this issue that
what we think of as the self, what you think
of as your body, just as a matter of control,
what can you control with your body? And I think
this is, by the way, why we understand our reflections
in the mirror to be us, because you move and
(18:22):
it moves, and so you're driving what you're seeing over there,
so you think, oh, yeah, that's me over there. Um,
But what this means is in you know, make up
a number thirty five years when we are controlling a
robot with our thoughts, it is essentially an extension of
our body. What it means is that that will become us.
(18:44):
It will be a part of of your body. All right,
We're gonna take a quick break, but I'll be right
back with David Eagleman. Thank alright, I'm back with David Eagleman.
In the book, you talk about the live wired brain
is um is being a place of competition, um based
on the input that's coming in. And I was just
(19:06):
really uh intrigued by this, uh, this new theory of
dreaming that you discuss. So would you would you mind
uh sharing that with our listeners. Yeah, um, yeah, this
is something very cool that's come out of our studies
of plasticity and UM here it is. It's that when
any part of the brain goes unused, it gets taken over.
(19:27):
And so for example, if you go blind, your systems
for hearing and touch and all of that real estate
will take over the part of the brain that we
used to call the visual cortex. So the surprise in
neuroscience has been how rapidly this happens um. What group
found about thirteen years ago was that if you take
(19:48):
sighted people and you blindfold them tightly and you stick
them in a brain scanner, within about an hour, you
can start seeing activity in the visual cortex just based
on um hearing or touch. If you touch them on
the hand or something, you start seeing activation in the
visual cortex. Now, it's not because the neurons have had
a chance to grow that fast from hearing and touch
(20:10):
into the visual cortex. Instead, there's all kinds of cross
wiring in the brain where those systems are already reaching
over into the visual cortex. It's just that they're normally
silenced and they're inhibited, so they don't get to do anything.
But that inhibition starts wearing off very quickly. And so
I was really shocked by the speed at which hearing
(20:30):
and touch could take over. And so my student and
I were talking about this one day, and what we
realized is there's a very critical thing that happens because
we live on a planet that rotates into darkness for
half the time. You know, in the dark, you can
still hear and touch and taste and smell and all
that just fine, but you can't see, and of course
I'm talking about evolutionary time, not recent electricity times. And so, um,
(20:52):
what this means is that the visual cortex has always
been in a big disadvantage when the planet rotates into darkness.
And so what we realized is, wow, if it doesn't
want to get taken over by the other senses, it
has to have some way of defending its territory. And
what we realized was that that's what dreams are. You
have this very specific circuitry that starts in the midbrain
(21:12):
and goes through a series of steps and just blasts
activity into the visual cortex every night, about every ninety minutes.
And and that's its only job. It's just blast activity
in there. It's very specialized circuitry. It's very specific of
the type of thing that, to the ananimous eye, is
not accidental. And so and of course, because it's our
(21:34):
visual cortex, we you know, we see and we think, oh,
I'm having this full, rich visual experience. Um. And of
course dream content might have to do with you know,
it certainly has to do with what you've experienced during
the day, in which synapses are still hot and so on.
But but the point is that it's just blasting activity
in there to defend the visual system against takeover. And
(21:55):
so we've now done big studies on this. For example,
where I'll just give you one thing that we just
published recently where we compare twenty five different species of
primates and we looked at how plastic they were, because
across even the primate kingdom, we have this um you know,
spectrum of how plastic you drop into the world and
then how much rem sleep they get in other words,
(22:15):
how much you know, rapid eye movement or or that
dreams sleep, because this is when dreams happen. And it
turns out that the more plastic you are as a species,
the more dream sleep you have because you need to
defend it more. As opposed to the other end of
the spectrum. Let's say lemurs drop into the world and
they're pretty much fully baked um and they have very
short you know, adolescents time and walking time and weaning
(22:37):
time and all that stuff. Um, they don't have much
dream sleep because they don't need it because their brain
is sort of baked into place. And by the way,
I'll just mention one other thing because people sometimes ask
about this, which is um you know, they say, do
blind people dream. Yes, blind people have dreams where activity
is getting shot into their occipital lobe at the back
of their head. But because they are blind, they don't
(22:59):
experience that is vision. Instead, they experience it is hearing
and touch. So blind people's dreams are all about you know,
weird bizarre things just like ours, but it's not involving vision.
It's you know, I'm I'm walking around my house and
all my furniture is rearranged, and I'm feeling stuff, and
then there's a bear and I'm feeling the bear and
all that kind of stuff. So um, But it's exactly
the same circuitry that they have, because this is a
(23:20):
very fundamental circuitry that has burned into the system, and
it doesn't care whether your eyes are working or not,
because it's it's more, it's deeper than that, and has
working on this has has changed the way you reflect
on your own dreams at all. You know, I've always
actually felt that dreams are not terribly meaningful like my
own you know, I wake up. I've always described this
(23:41):
as sort of sticking your head in the night blender
each night. I kind of hate dreams, um, But now
I have a deeper appreciation for why I'm going through
that night blender, because um, if not, I would wake
up in my visual system would be really disadvantaged. It
would be taken over in large part by hearing it
by touch. Especially in the later portions of the book,
(24:01):
you you get into two memories and and even identity,
and there's there's a lot that really seems to resonate
with the state of the world right now. How do
you feel this book speaks to the reader? Yeah, I
think there. I think there are many ways. Um, I'll
mention too. One is actually, let me start with this
optimistic one, which is um as lousy as has been
(24:26):
for everybody. And you know, this is a year where
there's serious spikes for everybody in stress, anxiety, depression. It's
just there's all kinds of bad stuff. But I will
mention one tiny silver lining of this is that from
the point of view of brain plasticity, we've all been
kicked off of our hamster wheels and we're all being
(24:47):
forced to rethink many things that we never thought about before.
So I mentioned before that our brain is locked in
silence and darkness, is trying to make an internal model
of the world out there and we all pretty much
had that. We thought, Okay, I get how the world works,
I get how things operate, how people respond, how to
get toilet paper, how to get food in my fridge,
(25:07):
stuff like that, and all of a sudden everything changed.
And from the point of view of brain plasticity, this
is actually really useful. It has forced a kind of creativity,
an unwanted one for sure, but it's forced kind of
creativity where you're having to rethink everything. We're having to
understand many things in more depth that we never thought
twice about before. And um, it turns out when we
(25:30):
look at things like you know, dementia, what happens is
people retire and they stop challenging themselves, and their brains
end up in a worse and worse state. And the
people who retire and end up fine and much better
off are those who keep challenging themselves with novel things.
And that includes even basic things like just you know,
(25:50):
making sure you're not just sitting around watching TV but instead,
you know, taking on new sorts of challenges and tasks
and keeping an active social life and stuff like that.
So anyway, this is what's happening to all of us.
And I have a slight suspicion this will be hard
to prove, but just an intuition that we may find
a slight dip in dementia um in in the coming
(26:10):
years for people who have been you have lived through
this early twenties um simply because they've really gotten a
chance to build all kinds of new roadways in their brain,
whereas they might not have done that as as adults.
The second thing that I'll mention as far as is
one of the things that my lab has been studying
for a very long time is social neuroscience, which is
(26:33):
this issue of how there's a lot of the brain
circuitry that's devoted to other people. In other words, you know,
we normally look at the brain and we think already
there's hearing, the touchows, vision, and so on, But in fact,
a lot of your circuitry has to do with modeling
other people. And you might know a thousand people and
you've actually got circuitry devoted to every one of them,
and circuitry devoted to okay, who knows who and have
(26:54):
they dated before and blah blah blah. I mean, it's
it's a very sophiskated social system that we're carrying around.
And so one of the things that got me interested
a long time ago, and we've published and written on
this for years, but suddenly it really is important. Is
this issue about in groups and now groups. And it
turns out that, um, we here, I'll just tell you
really quickly about a study we did. We we take
(27:14):
people into the brain scanner and we show them six
hands on a screen and the computer goes around and
selects one of the hands at random, and then you
see that hand get stabbed with a syringe needle. And
what happens is you really cringe when you see that.
It's it's awful to see somebody's hand get stablished with
a needle, and that activates this network in your brain
(27:35):
that summarized is the pain matrix, which is to say,
you're you're such a feeling the pain of that. Um
that is the neural basis of empathy. You care about
somebody else because you're immediately running a simulation of what
if that was my hand, even though it's not physically
your hand getting touched. But what we do then is
we put a one word label on each of these hands. Christian, Jewish, Muslim, Atheist,
(27:59):
Hindu scientologist and then the computer goes around and picks
a hand, and see the hand gets stabbing. The question
is do you care? Does your brain care as much
if it's someone in your outgroup versus a member of
your in group, And that's exactly what happens. If it's
a member of your in group, you have a much
bigger response, and if it's a member of your outgroup,
your brain doesn't really care that much. And it turns
(28:20):
out that we do all kinds of versions of this.
Just as one example, we then say, okay, the year
is twenty five, and these three religions have teamed up
against these three religions, and now your two allies you
care slightly more than you did a minute ago, just
because you're told in this one sense thing that that
(28:41):
they're allied with you, and the others are still clearly
in your out groups, so your brain just doesn't care
as much. And by the way, just as a side note,
atheists have exactly the same thing about seeing atheist hands
gets up. So it's not an indictment of religion. It's
just an issue about in groups and out groups who
you feel like, you know what your labels are. Um,
so we've done a lot of work on that, if
anyone's interested. I wrote in a uh an article in
(29:03):
The Economist last year called does your brain care about
other people? It depends? Um. But all of a sudden, unfortunately,
all of this stuff is more relevant because society is
really finding ways to divide themselves up with in groups
and now groups. Um. You know, some people blame social media.
The fact is, you know, I'm a real student of history,
(29:27):
and the fact is that we've had this kind of
stuff happened all the time, with the Chinese Cultural Revolution
or the Russian Revolution or you know, or what happened
to Nazi Germany or we we've we've seen this stuff
lots of times before the Internet. So it's not like
the Internet is this the single thing to blame here.
This is just human nature. Um. So anyway, this is
what I think is relevant. Alright, We're gonna take one
(29:49):
more break, but I'll be right back with David Eagelman.
Thank alright, I'm back with David Eagleman. So well, let's
let's take a brief journey into the future here again
coming back to the idea of neural technology in the
future allowing us to augment our senses our bodies. If you,
let's say you were to enter a state of suspended
(30:11):
animation and emerge a hundred years from now, how much
of the human sensory experience will have changed and how
different How difficult do you think it would be for
a twenty second century human to relate these senses to you? Yeah,
I think I think this is a key issue, which
is to say, we have certain what are called quality
(30:33):
of which is, you know, our internal experience of something
like vision and hearing and so on. And you know,
obviously the stuff is completely made up by our brains
in the sense that just an example, colors don't exist
in the world. All you have is different wavelength of
electromagnetic radiation. But your brain comes up with a way
of summarizing things quickly, so it can see the ripe
fruit against the green leaves. It says, okay, I'm gonna
(30:54):
call that red and that green perfect um, even though
that doesn't exist. So we have this internal experience of
the world. And of course, you know, sound also doesn't
exist as such, You've just got air compression waves, but
we turn it into you know, beautiful voices in music
and so on. Um, okay, but here's the thing, it's
because your brain has lots of experience with this that
(31:15):
it eventually turns it into this direct perceptual experience. And
so the question is, now, if you've fed in a
new kind of data stream through the Neo centry buzz,
for example, the wristband, if you fed in a completely
new kind of thing, would you come to have a
direct perceptual experience of it? And our data right now
suggests yes, that that you would. And the thing that's
(31:39):
so weird about this is there's actually no way to
describe it to somebody who has not had that experience.
So imagine that you had a friend who is color
blind and you tried to explain orange to your friend.
There's no way that she would understand. She could eventually
pretend and say, okay, rab' just quit talking and I'm
gonna pretend to understand, but she wouldn't ever understand orange.
(32:00):
This why because you have to experience it to get it.
And so um, and you know, if you have a
blind friend, try to explain what vision is your friends,
I don't understand. You're you're trying to You're you're capturing
fote that you're capturing millions of photons every second from
across great distances, and there's just no way that they
can understand what that's like. And so the same thing applies,
(32:24):
I think for twenty second century people who are getting
direct data streams fed to their brain of stock market
or microwave data information or um, you know, gamma ray
information or whatever the thing is that they're feeding in.
You're like the person who doesn't understand what orange is
or what vision is to them. And they can try
(32:44):
really hard to explain to you, and you can even
pretend at some point they understand, but you just won't.
And um, So I think we're on the verge of
a really interesting moment in history where where we're gonna
essentially start speciating, as in, people are going to have
such different experiences that they won't be able to relate
them to each other. Now, let me just say, there's
a sense in which this is no different from what
(33:06):
we've always had in the sense that you know, you
grew up in your hometown and had your experience. I
grew up my hometown and had my experiences. And there's
a sense in which brains are pretty different anyway. Um,
but this is just going to be more of that
where I'm you know, plugged directly into Twitter, and you're
plugged directly into infrared information and we just can't quite
get what the other person is experiencing. So you worked
(33:28):
as a science advisor on HBO's West World, that's right,
that's right, um. And you know, one of the things
that I've found in advising for television in general is
that there are all these topics that I and my
colleagues have debated for years, were you know, for example,
the question of could robot become conscious and what would
(33:49):
that mean? And would they have free will? And so on? Um,
and you know, we write all these academic papers on it.
But it's it's such a cool opportunity to get these
questions to, you know, into the public square with fiction.
And so something like west World is tremendously successful into
getting people to think about these sorts of questions. And
one of the things that I did as scientific advisor was, UM,
(34:13):
got our vest or neosensory vest into the show. So
you know, it was I don't know if anybody out
there I saw this episode during season two, but um,
these military contractors drop into west World to take care
of the hosts. The bad robots and they are feeling
on their vest their location of the robots. So, oh,
there's location over there there, sorry, there's a there's robot
(34:34):
over there. There's one over there, and then they can
shoot them accordingly. But we've actually used exactly that For
people who are blind, we've used the same idea, which
is a wearing the vest and they're feeling where people
are around them and oh, there's somebody coming up behind me,
there's someone over here on my left, and so on,
and then we can add navigation directions on top of that.
Um you know, so it buzzes okay, go four, oh go,
(34:55):
the left now goes straight and so on. Um. So yeah,
that was a very cool, very cool opportunity that we
had to get our technology into this futuristic show. I
love that sequence in the show because I felt like
like a lesser show would have just copied Aliens and
just had you know, blips on a map. Uh and
but this felt this, this felt thoroughly science fictional in nature,
(35:16):
you know. I mean, but then a golf course is
using actual technology that we're developing today exactly right now.
You mentioned West World bringing scientific topics or just topics
concerning things like consciousness out into the public square. The
first season at least discussed Julian james b cameral mind
hypothesis that brought that up a little bit. And I
(35:36):
know you wrote about this a little bit in incognito,
but what are your general thoughts on this hypothesis. You know,
what's interesting is that no one actually knows if it's
correct or not correct. So what Julian James proposed is
that it may be that you essentially have two sides
to the brain, the left and the right side, literally
the two hemispheres, and that those used to be more
(35:58):
separate and um, so it was as though people were
hearing a voice from somebody else. And what he argues
is that if you look at ancient literature, like ancient
Greek literature and so on, there's always this thing about
hearing a voice from God and so on. Um. And
the argument is that very recently the left and right
hemisphere started connecting in a deeper way, um, and so
(36:21):
there was this super highway of fibers that goes back
and forth between them. And so what we have now
is a unified consciousness instead of two separate voices going
on in our heads. As I said, nobody really knows
that this is right or not, because there's no simple
way to test this directly. What I argued, an incognito though,
is essentially a a distant cousin of that, which is
(36:44):
that what is absolutely clear is that we are not
a single thing. So we think of ourselves as individuals,
meaning not divisible into different parts. But but in fact
who you are is a collection of different neural networks
that all have different drives. And this is why we
can are you with ourselves and custed ourselves in contract
with ourselves, and canjole ourselves who's talking with whom? Here?
(37:05):
It's all us, but it's different parts of us. So
this is why if I take some warm chocolate chip
cookies out of the oven and put them in front
of you, part of your brain says, don't eat it,
you'll get fat, and party brain says that looks like
a high energy sort. You know, I totally want to
eat those cookies, And part of your brain says, okay,
how about I eat the cookies, but I'll go to
the gym tonight or whatever. Like everything that we do
(37:26):
in our lives, we have arguments with ourselves about Okay,
what should I do here? Part of me want to eat,
this part of me doesn't want to And so what's
going on? There are all the different voices, the different
political parties of this neural parliament that we have running
under the hood. And this is the framework that I
built in in incognito, is that we've got this parliament
and the way you go just depends on the majority
(37:48):
vote in any given moment, and so you're not one thing,
You're a collection of voters. All right. I have one
one last question for you. Um, if if you could
go back in time and serve as a sign advisor
on any past science fiction film, what would it be.
What would you most like to go back and tweak
or correct or make a little more neuroscientifically interesting? Oh gosh,
(38:11):
I'd have to think about that off the top of
my head. Um. Something like the Matrix is terrific because
that's an example actually of of a piece of fiction
that got everybody talking about this issue of how do
you know? Like you know, Decartes said, how would I know?
If I'm a brain in a vat um and and
(38:33):
I just think that I'm feeling and hearing and seeing
these different things and that that got upgraded that question
by philosophers um at different stages in history. But but
essentially that's the question is how do I how do
I know if there's a bunch of scientists that are
zapping my brain with electrodes that are making me feel
that I'm talking with you on zoom and the weather
is nice outside and so on. But then the matrix,
(38:56):
I think single handedly upgraded that question too. How do
I know if I'm in the matrix if I am
a simulation? And and as things have gone on, especially
in the last I don't know, ten years in Silicon Valley,
it feels like people talk about that question more and
more seriously all the time because you look at our
computational capacity and you think, well, gosh, it's it's really
not that hard to make super sophisticated VR in So
(39:18):
what's this gonna look like in twenty one twenty I mean,
you can make something that is absolutely convincing. I mean,
forget it, you can do that. It's just like a
convincing So the question is how would you know if
you exist in a simulation or not? And what they
cart concluded, by the way, is that there is no
way for him to know um, and this is what
led to his very famous declaration, japons don suite. I
(39:43):
think therefore I am um because what he meant by
that is, look, I don't know if I'm in a simulation.
But all I can tell you is that there's somebody
thinking about this question. So I exist, whoever, whoever, whatever
situation I'm actually and it doesn't matter. There's some eye
that exists. And that was actually a quite important move
(40:04):
in philosophy. But the point is, we have absolutely no
way of knowing if we are in a simulation or not.
And uh, we don't even have any good hypotheses about
how we would be able to find that out. And
by the way, it might not matter. I mean, you know,
if I told you with certainty that we are or
are not, it would it might not change anything about
what you're doing. Um So, But so I would love
(40:26):
to have been involved in in that movie and and
add in just a few neuroscience e uh twists and
sentences and questions there. Awesome, David, thanks again for chatting
with me today. Great, thank you, Robert. This is blessed
all right. So there you have it again. The book
is Live Wired the inside Story of the Ever Changing
(40:47):
Brain by David Eagleman. It's out now and if you
want to check out Neosensory you can just go to
neosensory dot com. If you'd like to listen to other
episodes of Stuff to Blow Your Mind, you can find
us where every at your podcast and wherever that happens
to be. We just asked that you rate, review and subscribe.
Thanks as always to Seth Nicholas Johnson for his recording
(41:08):
skills and editing skills and bringing all this together especially
short to turn around today. And if you would like
to email us about this interview, about this episode, or
about forthcoming episodes or past episodes, you can do so
at contact at stuff to Blow your Mind dot com.
(41:31):
Stuff to Blow your Mind is production of I Heart Radio.
For more podcasts for my Heart Radio, this is at
the Heart Radio app, Apple Podcasts, or wherever you're listening
to your favorite shows.
Hey, you welcome to Stuff to blow your mind. This
is Robert Lamb and I'm Joe McCormick, and it's Saturday
time for a Vault episode. This one originally aired September
twenty nine. Rob, this was the interview that you did
with the neuroscientist David Eagleman. Yeah, this is a lot
of fun gets that he gets into some really cool ideas.
Here a possible explanation for what dreams are for? And uh,
(00:29):
one of my favorite parts, how in which ways? Uh?
Is the human brain like a Mr Potato Is a
Mr Potato different from Mr potato Head? Well it's Mr
potato Head. Yes, Uh oh, I guess actually it's not
Mr It's just potato Head now right, Well, I think
now there is still a Mr. Potato Head, but there's
also a broader potato head concept. Okay, yeah, I haven't
(00:50):
followed all the potato head news, but I've I've caught
wind of some of the like the faux outrage over
over some of it. So at any rate, it's a
eagle and uses the potato head um as a wonderful
metaphor for exactly how our brain works when you plug
different sensory inputs into it, so I highly recommend it.
It's a great, great, really enjoyable interview. I enjoyed it.
(01:12):
I think folks will enjoy it as well. Welcome to
Stuff to Blow Your Mind, production of My Heart Radio. Hey,
welcome to Stuff to Blow Your Mind. My name is
Robert Lamb. Joe is away from work. He's realigning his
(01:33):
gray matter at the moment, so it's just me today,
but I'll be joined by neuroscientist, author, and science communicator
David Eagleman about his new book Live Wired, The Inside
Story of the Ever Changing Brain. Now we've mentioned David
Eagelman on the show many times before. He's an adjunct
professor at Stanford University and his CEO of Neo Sensory,
(01:55):
a company that develops devices for sensory substitution. You may
also know him from his previous books about the human brain,
his TV series The Brain with David Eagleman, and his
role as a scientific advisor on HBO's Westworld and the
TNT series Perception. I'm recording this on a Monday, and
I actually read Live Wired over the weekend. It's a
highly addictive read and one that I think our listeners
(02:17):
will will really enjoy. David does an amazing job breaking
down the inner workings of the brain via relatable pop
culture and historical metaphorth everything from the colonization of the
America's to Mr Potato Head and Ellen Ripley from Aliens.
It's published by Pantheon Books and you can currently grab
it as a hardcover, an e book, or an audio book.
(02:38):
And the fun thing is that that David reads the
audio book. It's always great when you when you get
that with an audio book. So, without without any further ado,
let's jump right in. David Eagleman, thanks for joining me today.
Great to be here, Robert. First of all, I have
I just have to say that this book was such
an engaging read. I actually read it all over the weekend,
(02:59):
and while I was familiar with some of the findings
and technologies discussed, there was plenty I hadn't been exposed
to yet, and it was all delivered in such a
fashion that it all ended up feeling like, you know,
it's kind of like a revelation, um, and I feel
like that revelation is really well summarized in the title
of the book, Live Wired. If you would, could you
summarize the basic difference between the idea of the live
(03:22):
wired understanding of our brain as opposed to previous notions
of how the brain worked. Yeah, I mean the whole
The whole thing is that when you first pick up
a neuroscience textbook as a young person, you see a
picture of the brain and it says this parts or vision,
this parts are hearing, the parts are touch, and so on.
But in fact, um, I guess what I've spent the
last twenty years, you know, in my laboratory really understanding
(03:46):
the lesson of is that the brain is a is
a dynamic system that's constantly moving around. And so for example,
if you go blind, the part that we would have
called your visual system gets taken over by hearing and touch.
If you lose an arm, the part of your body
map that has an arm gets taken over by neighboring
areas and so on. The whole thing is this incredibly
(04:06):
dynamic system. It's not like anything that we know how
to build. Um. You know, here in Silicon Valley where
I live, everything is about hardware and software, and engineers
are praised for building an efficient system where you've got
these two layers and that's it. Um. But what's happening
in our skulls is an entirely different kind of technology,
(04:26):
and so I in the book, I ended up coining
a new term for this, live wired or live ware.
And the idea with live ware is that every moment
of your life, this is reconfiguring itself. So you've got
eighty six billion neurons, these are the cell types of
the brain. You've got about point to quadrillion connections, and
(04:49):
every moment in your life, these things are changing their
strength of connection. They're unplugging, they're replugging elsewhere, they're seeking around.
What you have are these dense jungles. And you know,
this level of complexity is something that bankrupts our language.
We don't have any way of talking about point two
quadrillion connections moving and changing. But everything in your life,
(05:10):
every experience that you have um changes who you are.
When you learn, for example, that my name is David,
there's a physical change in the structure of your brain.
And that's what it means for you to then remember,
you know, two months later, who's the guy you had
on your podcast David. You know, it's like it's it's
this constantly changing system and it's UM unlike anything that
(05:31):
we know how to build at the moment. So, um,
you know, as you as you saw in the book.
I tell these different stories just by way of introduction
that are so fascinating, Like you can take out half
the brain in a child. For example, when children have
this really bad type of epilepsy, there's a surgery that
they go through. Half the brain is removed, and they're
(05:53):
just fine cognitively, they're totally fine because the rest of
their brain, the other half says, okay, I'm gonna read
are the functions that are that went missing from there.
Sometimes a child is born with only half a brain,
you know, and things just get get rewired so that
it all is there and we can't you know, you
can't do this with your cell phone or your computer.
(06:15):
You can't take out half the circuitry and expect it
to still function. But it works just fine, especially with
a young brain. Now, with all of this in mind,
into this live wired understanding of the brain in mind, um,
I thought we might back up to a very basic question,
uh that sometimes I guess we don't think about because
we're I mean, we were trapped in the brain. We
(06:36):
can't see the forest for the trees. But what what
does the brain do? So the brain is locked in
silence and darkness inside the vault of your skull, and
all it's trying to do is make a model of
the world, as in, I've got all this incoming data.
And by the way, the data that comes into the
brain is just spikes, just little electrical spikes in these neurons.
(06:59):
It doesn't know that these spikes represent photons, and these
spikes represent air compression waves, and these spikes represent mixtures
of molecules hitting a membrane and so on. All it
knows is I've got data coming in as zeroes and
ones and um and it knows that it can control
a body. And so it's job is to figure out,
all right, how do I control the body, how does
(07:20):
that change the spikes coming in? And how do I
make a model of the world. And this is an
extraordinary technology that we have carrying around on our shoulders.
Um As I said, we we don't know how to
build technology like this, and we're just scratching the surface
of even trying to figure this out. But that's what
the brain is doing, locked in its in its vault,
(07:40):
is figuring out, okay, how do I understand the world,
and and it's really extraordinarily good at at extracting patterns
and eventually making predictions. And um, yeah, that is that
is the main job that is trying to accomplish. Now,
the big part of the book deals with how our senses,
uh you know, speak to the brain and how the
rain works around limitations uh, such as they are the
(08:03):
ones you mentioned with the half of the brain being
missing at etcetera. And also uh you know, relating limbs
uh and uh and I love how you use these
various metaphors to explain that to the reader. Would you
mind uh explaining to our listeners how our brains are
like Mr potato head. Yeah, so this is something that
struck me many years ago where I realized that, so
(08:23):
we've got all these sensors like our eyes and our
ears and our nose and our fingertips, all these things
were used to and so we just sort of think
of these as fundamental. But but when you look across
the animal kingdom, what you find are all these other
weird kinds of sensors, things that you could take in
like snakes taken infrared information, honeybees taken ultra violet when
(08:44):
you look at something like the black ghost knifefish, it
has electro receptors where it's pulling in information about perturbations
and electrical fields. UM. Lots of birds and cows and
insects have magneto reception where they are picking up on
the magnet field of the planet and they're navigating that
way and so on. And what I realized is Mother
(09:04):
Nature doesn't actually have to recreate the brain every time
she does this. Instead, the principles of brain operation, she's
figured that out at the beginning, and then she can
just plug in anything she wants in terms of what
is the information that would be useful to sense. And
that's why I suggested this potato head model of how
(09:25):
to think about this, which is to say, you just
take any sensors and you stick it in and it's
good to go. The brain figures out, Okay, I've got
this kind of spikes coming in UM, and it seems
to correlate with this other sense, and it seems to
allow me to find food or avoid predators or whatever.
And so it just figures out what to do with
that information. And so this is a very new kind
(09:46):
of way to think about the brain. It's essentially understanding
the brain as a general purpose compute device. You feed
in whatever kind of data stream you want, and it's
and it's good to go. And this, you know, explains
a lot of what happens evolutionarily with janet x. It
just what it allows mother nature to do is just
tweak around with the genetics to make new kinds of sensors.
(10:08):
But one of the really amazing things you discussed in
this is that is that you can plug an eye
into an ear hole or an ear into an eye
hole on the Mr Potato head of our of our brain,
and the brain will roll with the data that that's
exactly right. And so this is an area called sensory substitution,
which is to say, you can feed information into the
(10:28):
brain via an unusual channel. And so something I started
in my lab about ten years ago was seeing if
we could build sensory substitution for people who are deaf.
So what we do. We started by building this as
a vest with vibratory motors in it. So you've got
a whole bunch of little buzzers like the buzzer in
your cell phone, and um, it captures sound and turns
(10:52):
out into patterns of vibration on the torso. And it
turns out that that worked really well. We could get
people who are profoundly deaf to start understanding what is
happening in the auditory world, just predicated on this spatio
temporal pattern of vibrations on their skin. And the reason
it worked is because it doesn't matter how the information
(11:12):
gets to the brain. As long as it gets there,
the brain will establish the correlations and figure out what
to do with it. So, as an example, if you see,
you know, the dog's mouth moving and you feel the
buzzing on your skin, you know, your brain puts that
together really easily. Or you know, you see somebody speaking,
or or we train people by showing a word and
you you know, you feel the word on the vest
and you start understanding what's going on. So what we
(11:34):
did then is we shrunk it down to the size
of a wrist band. And because you and I are
on video, Robert, you can see the wristband that I'm
wearing right now. It's you know, it looks about the
size of a fitbit, and it has very sophisticated computation
in here where it's capturing sound and turning that into
patterns vibration around the skin of the wrist and um.
(11:54):
So what we've been doing is we uh this Actually
now I spun a company out of my lab called
Neo Sensory, and we have been on the market since
March and we're now on risks all around the world.
So people who are deaf, for have hearing loss of
some degree where this and they are picking up on
the auditory world through their skin. Now, the interesting part
(12:17):
is this is exactly what the inner ear is doing.
Your inner ear is just registering vibrations of your ear
drum and it breaks sound up into from high to
low frequency, and then it ships it off to the brain.
And all we're doing is transferring the inner ear to
to the wrist and it works. So that's the idea
of sensory substitution. Is your um just getting the information
(12:40):
there via a different route and the brain figures out
what to do with it. And if this weren't amazing enough,
there's this then this this other additional step, this idea
of of plugging all new things into like new forms
of sensory information, new even uh you know, not only
limbs of replacement, but artificial addition. No limbs. You use
(13:00):
the example of doctor Octopus from the spider Man comics. Um,
can you tell us a little bit about how even
like this nineteen sixties sci fi concept is not that
far removed from our current understanding of the brain. Yeah, so, um,
let me actually let me say two things. Actually, one
is what we can do. So let me just separate
(13:22):
out sensory information coming in and motor information going out.
So sensory information coming in. One of the things we're
doing with the with our wristband called buzz um is
we can not only take in sound information for people
who are deaf, but we could actually expand the sensory
information that you would normally have. So, for example, with
somebody who's not deaf, we feed in ultra violet or
(13:45):
infrared or or things like that, where we're expanding senses
that you already have. And then we're doing this other
thing called sensory addition, where we're feeding in brand new
senses that you've never had. So we can feed in
any day to stream with this, like stock market data
or Twitter data or factory information or anything at all.
Feeding this in and as long as your brain can
(14:05):
make correlations with what it's seeing or hearing around it.
Then the brain can figure out how to utilize that information.
So we actually just finished a big developer contest where
people did all kinds of projects with you know, um
monitoring air quality or monitoring you know, blood sugar and
your bloodstream or um, um, many many different kinds of
(14:27):
monitoring of feeling, electrical fields and so on. UM. So
all this, by the way, if if anybody is interested,
we have an open a p I and an s
d K four buzz. You can get this on neo
central dot com and pursue any kind of project you
want this way. So we've had hundreds of people just
making their own thing, which has been which has been
very cool. Now to switch to the second thing about
(14:48):
motor output. UM, yeah, it turns out that your brain
UM is not pre programmed to drive your body, but
instead can figure out whatever the affordances are of whatever
is there. So just as an example, you know, one
of the things I tell the story about this dog
um that was born without fore limbs. It didn't have
(15:09):
his front legs, and so it just she walks by petally.
She walks on her back legs like a human, and
presumably any dog could do this, but they're not sufficiently motivated,
but so she just walks around her hind legs and um.
What this illustrates is that dog brains are not pre
programmed to drive dog bodies, but instead they figure out, Okay,
here's what I can do. I need to get to
my food, to my water, to my mother whatever. This
(15:30):
is how I do it. And so um. Also, I,
you know, tell the story of the guy who's the
world's best archer. He has the world's record for best
archery shot, and he doesn't have arms, so he does
this with his legs. And it's just another illustration that
the brain figures out whatever body it's in says okay,
I figure how to drive this. Of course, we see
this when people, for example, get an amputation. Let's say
(15:53):
they lose an arm and a motorcycle accent or something.
The map of their body in their brain readjust to say, okay,
I see I've got a body without an arm, so
I'm just gonna figure that out now. Okay. So, because
it is not pre programmed, it's extremely flexible. Um, I
(16:14):
think that we could actually build any kind of body
we want. So UM, coming back to your question, I
you know, mentioned about Doc Cock in the nineteen sixties,
which debuted in Spider Man. This scientist who plugs in
four robotic arms so that he can actually do extra
things and poor beakers and so on, and he controls
(16:34):
us with his brain. But then there's an explosion in
his lab and he turns evil and he scales buildings
and learns new forms of martial arts with with eight
arms and so on, and um, Dr Octavia starts to
go by Doc Cock anyway, Um, the exactly as you said,
this is not as far off and weird as we
used to think, because now what we're doing is with
for example, patients who are paralyzed. Um, you can put
(16:58):
electrodes into their motor cortex and they can learn to
drive a robotic arm even though they are paralyzed. They
drive the robotic arm with their thoughts, which sounds weird,
but that's of course, how you drive your fleshy arm.
You just you know, you think about it, you learn
the you learn what the output signals are that make
your arm respond. It's the same thing with the robotic arm,
and you can do that. And there have been experiments
(17:20):
with monkeys where they their bodies work fine. They're not paralyzed,
but they can drive a third arm with you know,
with their thoughts. So they're driving a robotic arm with
their thoughts. There was an experiment done where a monkey
um uses his motor cortex to make a robot walk.
But the interesting part was the robot happened to be
(17:40):
across the world. The monkey was in North Carolina and
the robot was in Japan, and the signals from the
monkey's brain were being sent over the internet and you
can get the robot, you know, the monkey to control
the robot just with the spikes in its motor cortex.
And so, UM, I think it's going to be no
time at all before we really to start controlling external
(18:02):
devices with our thoughts. And one of the things, one
of the frameworks that I build is this issue that
what we think of as the self, what you think
of as your body, just as a matter of control,
what can you control with your body? And I think
this is, by the way, why we understand our reflections
in the mirror to be us, because you move and
(18:22):
it moves, and so you're driving what you're seeing over there,
so you think, oh, yeah, that's me over there. Um,
But what this means is in you know, make up
a number thirty five years when we are controlling a
robot with our thoughts, it is essentially an extension of
our body. What it means is that that will become us.
(18:44):
It will be a part of of your body. All right,
We're gonna take a quick break, but I'll be right
back with David Eagleman. Thank alright, I'm back with David Eagleman.
In the book, you talk about the live wired brain
is um is being a place of competition, um based
on the input that's coming in. And I was just
(19:06):
really uh intrigued by this, uh, this new theory of
dreaming that you discuss. So would you would you mind
uh sharing that with our listeners. Yeah, um, yeah, this
is something very cool that's come out of our studies
of plasticity and UM here it is. It's that when
any part of the brain goes unused, it gets taken over.
(19:27):
And so for example, if you go blind, your systems
for hearing and touch and all of that real estate
will take over the part of the brain that we
used to call the visual cortex. So the surprise in
neuroscience has been how rapidly this happens um. What group
found about thirteen years ago was that if you take
(19:48):
sighted people and you blindfold them tightly and you stick
them in a brain scanner, within about an hour, you
can start seeing activity in the visual cortex just based
on um hearing or touch. If you touch them on
the hand or something, you start seeing activation in the
visual cortex. Now, it's not because the neurons have had
a chance to grow that fast from hearing and touch
(20:10):
into the visual cortex. Instead, there's all kinds of cross
wiring in the brain where those systems are already reaching
over into the visual cortex. It's just that they're normally
silenced and they're inhibited, so they don't get to do anything.
But that inhibition starts wearing off very quickly. And so
I was really shocked by the speed at which hearing
(20:30):
and touch could take over. And so my student and
I were talking about this one day, and what we
realized is there's a very critical thing that happens because
we live on a planet that rotates into darkness for
half the time. You know, in the dark, you can
still hear and touch and taste and smell and all
that just fine, but you can't see, and of course
I'm talking about evolutionary time, not recent electricity times. And so, um,
(20:52):
what this means is that the visual cortex has always
been in a big disadvantage when the planet rotates into darkness.
And so what we realized is, wow, if it doesn't
want to get taken over by the other senses, it
has to have some way of defending its territory. And
what we realized was that that's what dreams are. You
have this very specific circuitry that starts in the midbrain
(21:12):
and goes through a series of steps and just blasts
activity into the visual cortex every night, about every ninety minutes.
And and that's its only job. It's just blast activity
in there. It's very specialized circuitry. It's very specific of
the type of thing that, to the ananimous eye, is
not accidental. And so and of course, because it's our
(21:34):
visual cortex, we you know, we see and we think, oh,
I'm having this full, rich visual experience. Um. And of
course dream content might have to do with you know,
it certainly has to do with what you've experienced during
the day, in which synapses are still hot and so on.
But but the point is that it's just blasting activity
in there to defend the visual system against takeover. And
(21:55):
so we've now done big studies on this. For example,
where I'll just give you one thing that we just
published recently where we compare twenty five different species of
primates and we looked at how plastic they were, because
across even the primate kingdom, we have this um you know,
spectrum of how plastic you drop into the world and
then how much rem sleep they get in other words,
(22:15):
how much you know, rapid eye movement or or that
dreams sleep, because this is when dreams happen. And it
turns out that the more plastic you are as a species,
the more dream sleep you have because you need to
defend it more. As opposed to the other end of
the spectrum. Let's say lemurs drop into the world and
they're pretty much fully baked um and they have very
short you know, adolescents time and walking time and weaning
(22:37):
time and all that stuff. Um, they don't have much
dream sleep because they don't need it because their brain
is sort of baked into place. And by the way,
I'll just mention one other thing because people sometimes ask
about this, which is um you know, they say, do
blind people dream. Yes, blind people have dreams where activity
is getting shot into their occipital lobe at the back
of their head. But because they are blind, they don't
(22:59):
experience that is vision. Instead, they experience it is hearing
and touch. So blind people's dreams are all about you know,
weird bizarre things just like ours, but it's not involving vision.
It's you know, I'm I'm walking around my house and
all my furniture is rearranged, and I'm feeling stuff, and
then there's a bear and I'm feeling the bear and
all that kind of stuff. So um, But it's exactly
the same circuitry that they have, because this is a
(23:20):
very fundamental circuitry that has burned into the system, and
it doesn't care whether your eyes are working or not,
because it's it's more, it's deeper than that, and has
working on this has has changed the way you reflect
on your own dreams at all. You know, I've always
actually felt that dreams are not terribly meaningful like my
own you know, I wake up. I've always described this
(23:41):
as sort of sticking your head in the night blender
each night. I kind of hate dreams, um, But now
I have a deeper appreciation for why I'm going through
that night blender, because um, if not, I would wake
up in my visual system would be really disadvantaged. It
would be taken over in large part by hearing it
by touch. Especially in the later portions of the book,
(24:01):
you you get into two memories and and even identity,
and there's there's a lot that really seems to resonate
with the state of the world right now. How do
you feel this book speaks to the reader? Yeah, I
think there. I think there are many ways. Um, I'll
mention too. One is actually, let me start with this
optimistic one, which is um as lousy as has been
(24:26):
for everybody. And you know, this is a year where
there's serious spikes for everybody in stress, anxiety, depression. It's
just there's all kinds of bad stuff. But I will
mention one tiny silver lining of this is that from
the point of view of brain plasticity, we've all been
kicked off of our hamster wheels and we're all being
(24:47):
forced to rethink many things that we never thought about before.
So I mentioned before that our brain is locked in
silence and darkness, is trying to make an internal model
of the world out there and we all pretty much
had that. We thought, Okay, I get how the world works,
I get how things operate, how people respond, how to
get toilet paper, how to get food in my fridge,
(25:07):
stuff like that, and all of a sudden everything changed.
And from the point of view of brain plasticity, this
is actually really useful. It has forced a kind of creativity,
an unwanted one for sure, but it's forced kind of
creativity where you're having to rethink everything. We're having to
understand many things in more depth that we never thought
twice about before. And um, it turns out when we
(25:30):
look at things like you know, dementia, what happens is
people retire and they stop challenging themselves, and their brains
end up in a worse and worse state. And the
people who retire and end up fine and much better
off are those who keep challenging themselves with novel things.
And that includes even basic things like just you know,
(25:50):
making sure you're not just sitting around watching TV but instead,
you know, taking on new sorts of challenges and tasks
and keeping an active social life and stuff like that.
So anyway, this is what's happening to all of us.
And I have a slight suspicion this will be hard
to prove, but just an intuition that we may find
a slight dip in dementia um in in the coming
(26:10):
years for people who have been you have lived through
this early twenties um simply because they've really gotten a
chance to build all kinds of new roadways in their brain,
whereas they might not have done that as as adults.
The second thing that I'll mention as far as is
one of the things that my lab has been studying
for a very long time is social neuroscience, which is
(26:33):
this issue of how there's a lot of the brain
circuitry that's devoted to other people. In other words, you know,
we normally look at the brain and we think already
there's hearing, the touchows, vision, and so on, But in fact,
a lot of your circuitry has to do with modeling
other people. And you might know a thousand people and
you've actually got circuitry devoted to every one of them,
and circuitry devoted to okay, who knows who and have
(26:54):
they dated before and blah blah blah. I mean, it's
it's a very sophiskated social system that we're carrying around.
And so one of the things that got me interested
a long time ago, and we've published and written on
this for years, but suddenly it really is important. Is
this issue about in groups and now groups. And it
turns out that, um, we here, I'll just tell you
really quickly about a study we did. We we take
(27:14):
people into the brain scanner and we show them six
hands on a screen and the computer goes around and
selects one of the hands at random, and then you
see that hand get stabbed with a syringe needle. And
what happens is you really cringe when you see that.
It's it's awful to see somebody's hand get stablished with
a needle, and that activates this network in your brain
(27:35):
that summarized is the pain matrix, which is to say,
you're you're such a feeling the pain of that. Um
that is the neural basis of empathy. You care about
somebody else because you're immediately running a simulation of what
if that was my hand, even though it's not physically
your hand getting touched. But what we do then is
we put a one word label on each of these hands. Christian, Jewish, Muslim, Atheist,
(27:59):
Hindu scientologist and then the computer goes around and picks
a hand, and see the hand gets stabbing. The question
is do you care? Does your brain care as much
if it's someone in your outgroup versus a member of
your in group, And that's exactly what happens. If it's
a member of your in group, you have a much
bigger response, and if it's a member of your outgroup,
your brain doesn't really care that much. And it turns
(28:20):
out that we do all kinds of versions of this.
Just as one example, we then say, okay, the year
is twenty five, and these three religions have teamed up
against these three religions, and now your two allies you
care slightly more than you did a minute ago, just
because you're told in this one sense thing that that
(28:41):
they're allied with you, and the others are still clearly
in your out groups, so your brain just doesn't care
as much. And by the way, just as a side note,
atheists have exactly the same thing about seeing atheist hands
gets up. So it's not an indictment of religion. It's
just an issue about in groups and out groups who
you feel like, you know what your labels are. Um,
so we've done a lot of work on that, if
anyone's interested. I wrote in a uh an article in
(29:03):
The Economist last year called does your brain care about
other people? It depends? Um. But all of a sudden, unfortunately,
all of this stuff is more relevant because society is
really finding ways to divide themselves up with in groups
and now groups. Um. You know, some people blame social media.
The fact is, you know, I'm a real student of history,
(29:27):
and the fact is that we've had this kind of
stuff happened all the time, with the Chinese Cultural Revolution
or the Russian Revolution or you know, or what happened
to Nazi Germany or we we've we've seen this stuff
lots of times before the Internet. So it's not like
the Internet is this the single thing to blame here.
This is just human nature. Um. So anyway, this is
what I think is relevant. Alright, We're gonna take one
(29:49):
more break, but I'll be right back with David Eagelman.
Thank alright, I'm back with David Eagleman. So well, let's
let's take a brief journey into the future here again
coming back to the idea of neural technology in the
future allowing us to augment our senses our bodies. If you,
let's say you were to enter a state of suspended
(30:11):
animation and emerge a hundred years from now, how much
of the human sensory experience will have changed and how
different How difficult do you think it would be for
a twenty second century human to relate these senses to you? Yeah,
I think I think this is a key issue, which
is to say, we have certain what are called quality
(30:33):
of which is, you know, our internal experience of something
like vision and hearing and so on. And you know,
obviously the stuff is completely made up by our brains
in the sense that just an example, colors don't exist
in the world. All you have is different wavelength of
electromagnetic radiation. But your brain comes up with a way
of summarizing things quickly, so it can see the ripe
fruit against the green leaves. It says, okay, I'm gonna
(30:54):
call that red and that green perfect um, even though
that doesn't exist. So we have this internal experience of
the world. And of course, you know, sound also doesn't
exist as such, You've just got air compression waves, but
we turn it into you know, beautiful voices in music
and so on. Um, okay, but here's the thing, it's
because your brain has lots of experience with this that
(31:15):
it eventually turns it into this direct perceptual experience. And
so the question is, now, if you've fed in a
new kind of data stream through the Neo centry buzz,
for example, the wristband, if you fed in a completely
new kind of thing, would you come to have a
direct perceptual experience of it? And our data right now
suggests yes, that that you would. And the thing that's
(31:39):
so weird about this is there's actually no way to
describe it to somebody who has not had that experience.
So imagine that you had a friend who is color
blind and you tried to explain orange to your friend.
There's no way that she would understand. She could eventually
pretend and say, okay, rab' just quit talking and I'm
gonna pretend to understand, but she wouldn't ever understand orange.
(32:00):
This why because you have to experience it to get it.
And so um, and you know, if you have a
blind friend, try to explain what vision is your friends,
I don't understand. You're you're trying to You're you're capturing
fote that you're capturing millions of photons every second from
across great distances, and there's just no way that they
can understand what that's like. And so the same thing applies,
(32:24):
I think for twenty second century people who are getting
direct data streams fed to their brain of stock market
or microwave data information or um, you know, gamma ray
information or whatever the thing is that they're feeding in.
You're like the person who doesn't understand what orange is
or what vision is to them. And they can try
(32:44):
really hard to explain to you, and you can even
pretend at some point they understand, but you just won't.
And um, So I think we're on the verge of
a really interesting moment in history where where we're gonna
essentially start speciating, as in, people are going to have
such different experiences that they won't be able to relate
them to each other. Now, let me just say, there's
a sense in which this is no different from what
(33:06):
we've always had in the sense that you know, you
grew up in your hometown and had your experience. I
grew up my hometown and had my experiences. And there's
a sense in which brains are pretty different anyway. Um,
but this is just going to be more of that
where I'm you know, plugged directly into Twitter, and you're
plugged directly into infrared information and we just can't quite
get what the other person is experiencing. So you worked
(33:28):
as a science advisor on HBO's West World, that's right,
that's right, um. And you know, one of the things
that I've found in advising for television in general is
that there are all these topics that I and my
colleagues have debated for years, were you know, for example,
the question of could robot become conscious and what would
(33:49):
that mean? And would they have free will? And so on? Um,
and you know, we write all these academic papers on it.
But it's it's such a cool opportunity to get these
questions to, you know, into the public square with fiction.
And so something like west World is tremendously successful into
getting people to think about these sorts of questions. And
one of the things that I did as scientific advisor was, UM,
(34:13):
got our vest or neosensory vest into the show. So
you know, it was I don't know if anybody out
there I saw this episode during season two, but um,
these military contractors drop into west World to take care
of the hosts. The bad robots and they are feeling
on their vest their location of the robots. So, oh,
there's location over there there, sorry, there's a there's robot
(34:34):
over there. There's one over there, and then they can
shoot them accordingly. But we've actually used exactly that For
people who are blind, we've used the same idea, which
is a wearing the vest and they're feeling where people
are around them and oh, there's somebody coming up behind me,
there's someone over here on my left, and so on,
and then we can add navigation directions on top of that.
Um you know, so it buzzes okay, go four, oh go,
(34:55):
the left now goes straight and so on. Um. So yeah,
that was a very cool, very cool opportunity that we
had to get our technology into this futuristic show. I
love that sequence in the show because I felt like
like a lesser show would have just copied Aliens and
just had you know, blips on a map. Uh and
but this felt this, this felt thoroughly science fictional in nature,
(35:16):
you know. I mean, but then a golf course is
using actual technology that we're developing today exactly right now.
You mentioned West World bringing scientific topics or just topics
concerning things like consciousness out into the public square. The
first season at least discussed Julian james b cameral mind
hypothesis that brought that up a little bit. And I
(35:36):
know you wrote about this a little bit in incognito,
but what are your general thoughts on this hypothesis. You know,
what's interesting is that no one actually knows if it's
correct or not correct. So what Julian James proposed is
that it may be that you essentially have two sides
to the brain, the left and the right side, literally
the two hemispheres, and that those used to be more
(35:58):
separate and um, so it was as though people were
hearing a voice from somebody else. And what he argues
is that if you look at ancient literature, like ancient
Greek literature and so on, there's always this thing about
hearing a voice from God and so on. Um. And
the argument is that very recently the left and right
hemisphere started connecting in a deeper way, um, and so
(36:21):
there was this super highway of fibers that goes back
and forth between them. And so what we have now
is a unified consciousness instead of two separate voices going
on in our heads. As I said, nobody really knows
that this is right or not, because there's no simple
way to test this directly. What I argued, an incognito though,
is essentially a a distant cousin of that, which is
(36:44):
that what is absolutely clear is that we are not
a single thing. So we think of ourselves as individuals,
meaning not divisible into different parts. But but in fact
who you are is a collection of different neural networks
that all have different drives. And this is why we
can are you with ourselves and custed ourselves in contract
with ourselves, and canjole ourselves who's talking with whom? Here?
(37:05):
It's all us, but it's different parts of us. So
this is why if I take some warm chocolate chip
cookies out of the oven and put them in front
of you, part of your brain says, don't eat it,
you'll get fat, and party brain says that looks like
a high energy sort. You know, I totally want to
eat those cookies, And part of your brain says, okay,
how about I eat the cookies, but I'll go to
the gym tonight or whatever. Like everything that we do
(37:26):
in our lives, we have arguments with ourselves about Okay,
what should I do here? Part of me want to eat,
this part of me doesn't want to And so what's
going on? There are all the different voices, the different
political parties of this neural parliament that we have running
under the hood. And this is the framework that I
built in in incognito, is that we've got this parliament
and the way you go just depends on the majority
(37:48):
vote in any given moment, and so you're not one thing,
You're a collection of voters. All right. I have one
one last question for you. Um, if if you could
go back in time and serve as a sign advisor
on any past science fiction film, what would it be.
What would you most like to go back and tweak
or correct or make a little more neuroscientifically interesting? Oh gosh,
(38:11):
I'd have to think about that off the top of
my head. Um. Something like the Matrix is terrific because
that's an example actually of of a piece of fiction
that got everybody talking about this issue of how do
you know? Like you know, Decartes said, how would I know?
If I'm a brain in a vat um and and
(38:33):
I just think that I'm feeling and hearing and seeing
these different things and that that got upgraded that question
by philosophers um at different stages in history. But but
essentially that's the question is how do I how do
I know if there's a bunch of scientists that are
zapping my brain with electrodes that are making me feel
that I'm talking with you on zoom and the weather
is nice outside and so on. But then the matrix,
(38:56):
I think single handedly upgraded that question too. How do
I know if I'm in the matrix if I am
a simulation? And and as things have gone on, especially
in the last I don't know, ten years in Silicon Valley,
it feels like people talk about that question more and
more seriously all the time because you look at our
computational capacity and you think, well, gosh, it's it's really
not that hard to make super sophisticated VR in So
(39:18):
what's this gonna look like in twenty one twenty I mean,
you can make something that is absolutely convincing. I mean,
forget it, you can do that. It's just like a
convincing So the question is how would you know if
you exist in a simulation or not? And what they
cart concluded, by the way, is that there is no
way for him to know um, and this is what
led to his very famous declaration, japons don suite. I
(39:43):
think therefore I am um because what he meant by
that is, look, I don't know if I'm in a simulation.
But all I can tell you is that there's somebody
thinking about this question. So I exist, whoever, whoever, whatever
situation I'm actually and it doesn't matter. There's some eye
that exists. And that was actually a quite important move
(40:04):
in philosophy. But the point is, we have absolutely no
way of knowing if we are in a simulation or not.
And uh, we don't even have any good hypotheses about
how we would be able to find that out. And
by the way, it might not matter. I mean, you know,
if I told you with certainty that we are or
are not, it would it might not change anything about
what you're doing. Um So, But so I would love
(40:26):
to have been involved in in that movie and and
add in just a few neuroscience e uh twists and
sentences and questions there. Awesome, David, thanks again for chatting
with me today. Great, thank you, Robert. This is blessed
all right. So there you have it again. The book
is Live Wired the inside Story of the Ever Changing
(40:47):
Brain by David Eagleman. It's out now and if you
want to check out Neosensory you can just go to
neosensory dot com. If you'd like to listen to other
episodes of Stuff to Blow Your Mind, you can find
us where every at your podcast and wherever that happens
to be. We just asked that you rate, review and subscribe.
Thanks as always to Seth Nicholas Johnson for his recording
(41:08):
skills and editing skills and bringing all this together especially
short to turn around today. And if you would like
to email us about this interview, about this episode, or
about forthcoming episodes or past episodes, you can do so
at contact at stuff to Blow your Mind dot com.
(41:31):
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On Purpose with Jay Shetty
I’m Jay Shetty host of On Purpose the worlds #1 Mental Health podcast and I’m so grateful you found us. I started this podcast 5 years ago to invite you into conversations and workshops that are designed to help make you happier, healthier and more healed. I believe that when you (yes you) feel seen, heard and understood you’re able to deal with relationship struggles, work challenges and life’s ups and downs with more ease and grace. I interview experts, celebrities, thought leaders and athletes so that we can grow our mindset, build better habits and uncover a side of them we’ve never seen before. New episodes every Monday and Friday. Your support means the world to me and I don’t take it for granted — click the follow button and leave a review to help us spread the love with On Purpose. I can’t wait for you to listen to your first or 500th episode!
Las Culturistas with Matt Rogers and Bowen Yang
Ding dong! Join your culture consultants, Matt Rogers and Bowen Yang, on an unforgettable journey into the beating heart of CULTURE. Alongside sizzling special guests, they GET INTO the hottest pop-culture moments of the day and the formative cultural experiences that turned them into Culturistas. Produced by the Big Money Players Network and iHeartRadio.
Crime Junkie
Does hearing about a true crime case always leave you scouring the internet for the truth behind the story? Dive into your next mystery with Crime Junkie. Every Monday, join your host Ashley Flowers as she unravels all the details of infamous and underreported true crime cases with her best friend Brit Prawat. From cold cases to missing persons and heroes in our community who seek justice, Crime Junkie is your destination for theories and stories you won’t hear anywhere else. Whether you're a seasoned true crime enthusiast or new to the genre, you'll find yourself on the edge of your seat awaiting a new episode every Monday. If you can never get enough true crime... Congratulations, you’ve found your people. Follow to join a community of Crime Junkies! Crime Junkie is presented by audiochuck Media Company.