a very warm welcome

to this how to academy event my name is

matt stadler and i'm a presenter

on the national radio station lbc

leading britain's conversation

and this evening we're kind of leading a

global conversation

from here in notting hill and also with

david who is

stateside and in a moment if you haven't

seen it already

you'll get to understand why lockdown

must have been a particular pleasure for

him because he lives in the most

extraordinary

house i'm delighted to introduce to you

someone you'll probably have come across

in many different guises already

including perhaps at the how to

academy david eagleman he's a

neuroscientist

he's a an nyt new york times best

selling author he heads up the center

for science

and law he's also an adjunct professor

at stanford and he's going to tell us

all about how your brain works

and mine and perhaps the differences

between the two

he's the author of live wired and that's

why this

conversation is called live wired the

inside story

of the ever changing brain i found an

absolutely fascinating book it taught me

all sorts of things about myself that i

didn't know

already and i can't wait to share a lot

of what i've learned

over the course of the next hour or so

if you want to join in as ever

with these virtual events of course we

prefer to be on stage

let's hope that we will in the not too

distant future in fact a

journalist friend of mine just tweeted

from bergamo in italy which was once

upon a time

the epicenter or one of the epicenters

of this pandemic and he was saying it's

open

and things don't just get worse they can

actually get better anyway we are here

and we have to make do with this virtual

defense so you can put your questions

to david virtually in the q a box and

i'll try to get through as many of those

as i can

but david if you wouldn't mind starting

just with a briefish

synopsis of why you wrote the book and

what's at the heart of it very warm

welcome to you

great thanks matthew it's terrific to be

here i'm

i'm sorry that i can't be there in

person this year i've been to the how to

academy many times but i'm so pleased

that

everybody could uh could join today and

speaking of things virtual this

background is virtual this is not

actually my house i'm actually in my

garage so

it's not as great as it appears here

okay so

um here's what i want to talk about is

is um

is the human brain and what is different

about it with the

with other species that are close

cousins and

what that leads to what this means for

our lives so

um okay let me see if i can get this

going great

so you know maybe some of you have seen

a baby

zebra get born or a baby giraffe or a

baby dolphin and

what you'll notice is that within about

45 minutes

these uh animals are running around so

you know zebra wobbles to its little

pencily legs and then it starts uh

running around

and if you've ever seen a homo sapiens

get born you notice that it doesn't

happen that fast it doesn't take 45

minutes for them to walk

instead it takes years and and

what this represents is this incredible

trick on the part of mother nature that

she discovered with humans which is

instead of trying to hardwire everything

in at birth mother nature found this

simpler and incredibly successful

strategy which is allow neurons to

self-modify based on

experience and as a result of this

little clever tweak in the genes that

led to this strategy

we have taken over every corner of the

planet we've left the planet we've

uh you know invented the internet and a

million other things because we're this

incredibly successful species now

this is what's known as as brain

plasticity the ability for the brain to

reconfigure itself and the key thing

that i argue in the book is that you

cannot

think about the brain as hardware and

you cannot think about it as

a software it's instead what i call

livewear

and i prefer this term over the argot of

the field which is

brain plasticity because plasticity was

coined

by uh it's a term that was coined by

william james the

the great american psychologist who's

who was impressed by the way that you

can mold

plastic and you know you can take um

you can take something that's a plastic

material and you mold it into a shape

and then it holds that shape and so what

he was indicating was

hey you can mold the brain into shape

and then it it keeps that and that's

great and that's true the key is

brains are reconfiguring their whole

lives so your

entire life your 86 billion neurons and

your

trillions of connections are constantly

moving and

unplugging and re-plugging and changing

you've got

this this dynamic living electric fabric

that

is um you know constantly reconfiguring

itself until the day you die

and that is why i think we need an

upgrade from the term

plasticity because given what we

are now seeing going on the word plastic

doesn't uh

doesn't cut it anymore and so that's why

i've suggested livewire

as the uh as the term for this and so

my goal in the book and in this

extremely short talk is just to take you

know sort of the 30

000 papers on brain plasticity

and and filter them down to what i think

are the

main principles the the emerging picture

that i can see

when i squint it at everything that's

going on and that's what i'm going to

tell you about

uh very briefly is just a few of them so

um i think the first thing for us to

really appreciate is that

unlike computers brains are

extraordinarily flexible

so i'll give you an example of this um

this was a clinical case a few years ago

a 44 year old man

normal iq he went to the doctor because

he was having some leg pain

the doctor couldn't figure anything out

so he sent him for a brain scan to see

if they could find anything what they

found was an enormous surprise because

normally

this is a this is a brain scan this is a

slice right down the middle so you're

seeing the side of the brain

and let's see i don't know if you can

see my mouse here

uh no but it doesn't matter the um the

the one that's labeled number three

this is the lateral ventricle it's just

it's a little

space in the brain that's filled with

cerebrospinal fluid

anyway the reason i'm telling that

detail is because this gentleman's

brain scan looked like this he had

what's called hydrocephalus

the um the fluid was putting too much

pressure and it squished his brain up

against the sides of his skull

and that's what his brain looked like

and the the crazy part is his brain had

looked like that

his whole life no one had you know ever

done a brain scan on him before

but the thing is he was perfectly normal

he held a perfectly good job he had a

family

all the stuff even though his brain

looked like that

and so this illustrates the remarkable

flexibility

of this kind of material and the thing

is you cannot take your

cell phone or your laptop and pull half

the motherboard out

and expect it to still function but what

we have in here

our livewear is a completely different

kind of beast

and um you know we're all walking around

with this

existence proof that this completely

futuristic material

exists um and we're but we're just

scratching the surface in terms of

understanding how to how to build this

how to even understand something like

this and

it gets better because

a common surgery for children who have

epilepsy in an entire hemisphere half of

their brain

is to do a hemispherectomy where you

remove

half of the brain and as long as you do

this in a child under about seven years

old

they're perfectly fine they have no

problem with it they they often have a

slight limp

on the other side because this side of

the brain controls the other side of the

body

they have a slight limp but cognitively

they're perfectly fine

because all the functions that would

have existed

on this real estate over here get

rewired onto the remaining

real estate and um and

you wouldn't know it if you met a kid

who had half

of his brain removed and so there are a

number of examples of this sort of thing

in um in the book and uh

so that's the first thing that i very

briefly want to emphasize is that it's a

completely different beast than what we

know

how to build with our hardware and

software layers okay the second

thing i want to mention is that brains

match themselves

to their inputs so starting the 1960s

people discovered that there was a

map of the body in the brain so

on the left here on your somatosensory

cortex which is the part of your brain

that gets information from the body you

have a map

and um areas with higher sensitivity

are are represented in with more real

estate

and on the right here i'm showing the

motor cortex where there's a map of the

body so if you stick an electrode in

there at any point and you zap it

you know i might twitch my finger or

move my lip or move my toes or something

depending on where he's at

so people discovered this and they

thought wow this is terrific

it must be that this is genetically

pre-specified which would be a great

guess but it turns out that's not

the answer and the reason we know that

is because if somebody let's say

loses an arm the map changes

so the whole question is how does the

brain which is locked in silence and

darkness and the vault of your skull

have any idea what the what the body

looks like

and so i go into that in the in the book

how the how the brain

figures out what the what it's

controlling what it's

driving but the point is that when the

body plan changes

the brain changes and the reason i

showed a picture of

admiral lord horatio nelson here is

because

even though he towers over trafalgar

square

a lot of people never notice that he's

actually missing his right arm and the

reason he's missing his right arm is

because it was

shot off by a musket ball um

in in a one of his naval battles and um

[Music]

and he experienced phantom pain he you

know he wrote eloquently about what it

was like for him to live with one arm

but what we now know

is that his brain readjusted

um when this happens so this means it is

not genetically pre-specified instead

the brain

figures out whatever body plan it's

it's driving and i think the way to

think about this

is um you know i uh i suggest in the

book the way to think about is this like

as colonization so

as an example the french grip on the new

world if you look at that through time

they had a big grip on the new world for

a while

and then it diminished and had

everything to do with how many ships

they were sending over

because the british and the spanish were

just sending over more ships of people

and um as the french over time sent more

and fewer people their grip on the new

world waxed and waned

and so um this is the same thing when

you

you know when uh lord nelson sends over

fewer

ships of data from his missing arm

because it's now missing it's not

sending the ships over that territory

gets taken over

just like it does with any competing

territory because one of the things to

understand about the brain is there's

always uh competition going on between

all the areas

now what i've shown you so far was just

about when someone loses an arm but this

happens with

any incoming data so for example if you

lose your eyes the part of your brain

that we normally think of as the

visual cortex becomes no longer visual

so

when you look at what's going on in this

part of the brain in people who are

let's say born blind

you find that this part of the brain

responds to sound and responds to touch

because nothing lies fallow

it's like if um you know if some

restaurant went out of business in

london

it's not going to just sit there empty

for years it gets taken over by

by other competitors and so that's

exactly

what happens here and um you know so as

a result for a blind person

sound and touch move in here but also

memorization of vocabulary words and

math problems and so on

and um if you actually disrupt the

activity there

by putting in some magnetic pulses for

example

they get worse at touch and detecting

braille and so on so we know that that's

what's actually going on

in that part of the cortex now the

really interesting part one one of the

really fascinating things for me

that's been discovered just in recent

years is how unbelievably

rapid this takeover of the territory is

so

if you um blindfold somebody

tightly and you stick them in the

scanner

what investigators discovered just over

a decade ago is that you start

seeing activity in their visual cortex

in response to

touch or sound or things like that and

you see that

unbelievably rapidly within within about

an hour you start getting this

encroachment it's very light at first

but

what happens is this takeover from the

neighboring census starts happening

rapidly and the the surprise of these

findings was their

sheer speed um and in the book we come

to understand how that happens and why

the brain is so

fluid but i think the key is

you can't really think about the brain

the way it's typically taught in

textbooks which is okay here's the brain

here's the this parts revisions parts of

hearing touch and so on

it that's only true most of the time

based on what's plugged into it

but in fact the whole thing is a fluid

system and depending on where the data

is coming from

and what is relevant it completely

changes its distribution of territory

and this speed by the way um led me in a

student of mine in my lab

to a completely novel theory

about why we dream

and i'll just tell you very briefly the

issue has to do with the rotation of the

planet so

what happens is we get cast into

darkness for

half the time and um and of course i'm

talking about

during evolutionary time scales not

during you know current evolutionary

uh electricity blessed times so we

um were cast into darkness and in the

dark your touch and your hearing and all

that stuff works fine but your vision

does not work fine

and so it turns out that when we

sleep your visual

system is in danger of getting taken

over by hearing and touch

and so the hypothesis is that dreaming

is about

slamming activity into the visual cortex

about every 90 minutes during the night

to keep it protected

against takeover from neighboring senses

and when you look

at the circuitry that underlies dream

sleep

it starts in the midbrain and it takes

this very specific pathway

up and just slams into the visual cortex

and it's it's just driving activity into

there and

and nowhere else and so um

this this is what led us to this

hypothesis that dreams are the brain's

way of fighting

take over from the other senses and

there's much more on this in the book

and uh and if anyone's interested you

could read the scientific paper on this

as well

um okay great so

the uh the next thing of of

great interest the next principle for us

is how you can actually

what what senses are going into the

brain because the brain

wraps around whatever senses you

feed it so um

so i gave a talk at ted a few years ago

on this topic if you want to watch us

online

we built a vest in my lab and the vest

is covered with vibratory motors

and we for example for people who are

deaf

we capture sound and translated patterns

vibration on the skin and i just

realized

yeah i just realized the audio is not

going to work here

but what what's happening is i'm

actually speaking here

and as i'm speaking the sound is getting

translated

into pattern observation on the skin

from low to high and you might get a

sense of it from here so on the left the

woman is saying

sound and on the right she's saying the

word touch and so

the the motors are mapped from low to

high frequency and as she says sound it

does that when she says touch

it goes up like that and and this is

what's known as

sensory substitution where we can feed

data into the brain through an unusual

channel the skin in this case

and uh and the brain it turns out does

not care how it gets the data

as long as the data gets there because

as i said the brain is locked in silence

and darkness

and it's just trying to figure out

what's going on the outside world

and all the data that comes in is just

in the form of electrochemical spikes

just these little

spikes in the neurons and

and it turns out that you can't tell the

difference between

spikes that are carrying information

about photon capture or

air compression waves or pressure and

temperature it's all it all looks

exactly the same on the inside

of the brain so it turns out you can get

information in there via different

routes i'll just show you this is our

very first

participant who wore the vest he trained

for four days

my graduate student scott says a word he

says the word you

and the gentleman on the left who's

completely deaf

feels the pattern vibrations on his vest

and is able to

translate that into an understanding of

what is getting said

so now scott says the word touch

and he and jonathan feels is on the vest

and he's able to

to translate this um we now shrunk this

down to the size of a wristband i'm just

seeing if i have one here

um i may not so but

but we we have this wristband and um

this was our very first prototype

wristband here that's why this looks big

and clunky

but the uh gentleman here is describing

what it is like for him to be able to

pick up on sound

just through patterns vibration on his

skin um

and so i ended up spinning off a company

from my lab

called neo sensory and we're now on

risks all over the world

um and we uh allow people

who are deaf or have high degrees of

hearing loss to feel sound on their skin

it gets their brain that way and they

can

operate with that so you know this is

just people who are telling us what it's

like for them and what they can get and

so on

um i'll just mention also i'm a

scientific advisor on the show westworld

and so we put our vest into that show i

don't know if anyone saw

and so now i call it vest world by the

way but i don't know if anyone saw

what was this uh episode seven in season

two but these are our vests here

and so uh if you look at the guy in the

middle here you can see the vest light

up so

what what's going on here is he's

feeling the location of the robots the

hosts

uh on his skin and so he feels spatially

oh there's one off to the left there's

one on the right so

and even in the dark and so on he can

dispatch them accordingly

um and you know like here for example

they feel another they feel that there's

a

host there and they weren't expecting

that and they get killed and so this

just goes to show that if robots go bad

my vest

won't help you but what we were able to

do is

uh take this idea and implement it in

real life with people who are blind so

in this case um there's lidar set up

in the offices and this gentleman who's

blind can feel the location of everyone

around you can feel oh there's someone

up

ahead of me on the left and there's

someone approaching me from behind and

so on

he feels what's going on on top of that

we're adding navigation direction so

even though he's never been here before

he can just follow the buzzing on his

vest and navigate

accordingly so there's a lot of um

there's a lot that we're doing there um

okay and so um yeah the next

principle is that the brain figures out

how to control whatever body

it's in so not just inputs but outputs

so

um for example i mentioned this thing

about the map of the body and the brain

and how

it had been assumed at one point that

maybe you're just born with that

we're getting a lot more insight

nowadays into how flexible

the map of the body is and what it can

drive and so one example that i use in

the book is about this dog named faith

who was born without front legs and um

so she needed to get to food and water

and her mother and so on and so she just

figured out how to walk on her back legs

it's actually not that hard

uh you've probably not seen dogs do this

before why because dogs don't need to

walk on their back legs they don't have

it's not relevant

for them and so they don't do it but it

turns out it's not that hard

for dog to figure this out and so what

this demonstrates

is the dog brain does not

drop into the world expecting to drive a

dog body

instead it drives whatever it finds uh

whatever it

discovers it is inside of and we find

all kinds of examples like this one that

i use in the book is this guy who's the

world's best archer

he's got the world record for the

longest accurate shot he has no arms

and so he shoots with his feet why

because it was relevant to him and he

wanted to figure out

how to do it and so he was easily able

to do it

um this is actually from my show the

brain

um this is a woman who's paralyzed

completely and so

she got this brain implant in her motor

cortex

that allows her to control a very

beautiful robotic arm

across the room so she's controlling

this with her

thoughts by thinking about you know

moving her own arm which of course can't

move because the spinal cord is damaged

so the signals are not getting through

there

but so she just thinks about this and

controls the arm this way and she's

gotten better and better in part

because the engineers have tweaked the

algorithm but in large part it's because

her brain has figured out exactly how to

drive

this arm because it's plastic and able

to do so

and uh one of the things worth noting is

that we're just starting to scratch the

surface of this in terms of

how to build a completely new how to

rethink robotics in a completely

different way so i'll just give you an

example

this is from my colleague hod lipson um

the idea

is you build a robot this is called the

starfish

and the robot is not pre-programmed

to know what its body is in fact it's

not programmed at all to know what its

body is

and it experiments to figure it out it

puts out actions

it feels what happens in terms of its

balance and so on

and it figures out how to walk that way

it figures out how to move itself

and then one of the things that you can

do is you know

knock a leg off of it or something and

it'll figure out how to operate

uh with its new body plan and that's

what humans are so good at doing we

operate with new body plans all the time

as in you get on a bicycle or a

surfboard or a skateboard or whatever

and you know your evolution didn't

foresee

wheels coming of for a bicycle but it

has no problem just figuring that out

and then incorporating that into the

resume of what you can do

um okay so um

all right last last principle i'll

mention is that

we all these principles which i've uh

you know worked to distill into the book

and and

you know tell them around stories and so

on um

we can leverage this to build new kinds

of devices so just as an example

i was watching carefully you know what

happened when we got the mars rover

spirit to the red planet and of course

it was so exciting and it did a great

job

and it you know it was a multi-billion

dollar project but what

happened as you may know is it got its

right front wheel

caught in the mar stuck in the martian

soil and and it died

um and if you compare that to let's say

a wolf

who gets its leg caught in a trap you

may know what the wolf does is it'll

chew its leg off

and then it figures out how to walk on

three legs it was not genetically

pre-programmed to walk on three legs but

it just figures it out

through a series of feedback and and

and relevance and so on and so wouldn't

it be great if we could build robots

like spirit that could say oh geez i'm

stuck i'm going to chew my

wheel off and then figure out how to

operate this body plan

uh differently so the wolf carries on

with the limp because

animals don't shut down with moderate

damage and neither

should our machines so in the last part

of the book i talk about what i see is

the biological

future of machines okay so that's all

i'm going to say by way of introduction

and uh at this point i'd love to uh

matthew chat with you you reintroduced

me

it's fascinating stuff there's so many

different

jumping off points i've got about

squillian questions my first is

how much do you think we understand

about our brains

now it's impossible to put a number on

it because you would have to know what

the 100 mark is to even say how much we

know but clearly we know very

little i mean we're just at the foot of

the mountain and that's because

this what we're talking about is

unrivaled in terms of its complexity in

terms of anything we've ever discovered

as i mentioned earlier there's 86

billion neurons every neuron in your

head is about as complicated as the city

of london

it has the entire human genome in it

it's trafficking millions of proteins

around

in very complicated biochemical cascades

and each one of these is

interacting with about 10 000 of its

neighbors over this you know 0.2

quadrillion connections so this kind of

thing

bankrupts our language and totally

boggles the mind a system of that kind

of complexity

and all we have riding on top of that is

just our

you know our consciousness where we

think oh i'm hungry you know i'm sleepy

whatever the thing is but

there's an enormous happening under the

hood

and so we know very little and by the

way in 2006

actually i wrote the cover article in

discover magazine

called 10 unsolved mysteries of the

brain

and the reason i mentioned the year is

because when i look back in 2020

we still don't we haven't made no

progress on any of those big questions

questions like

consciousness you know how do you ever

build a machine out of physical pieces

and parts and get

consciousness out of it have it you know

feel private subjective internal

experience

it's a supreme irony that our minds are

boggled

by our own minds i mean you mentioned

consciousness

how do you understand consciousness in

its most basic form

yeah it's the thing that flickers to

life when you wake up in the morning

if you meant what is the definition of

it but how to understand

it not only do we not have a good theory

about it we don't even know

what such a theory would look like

because

there's no way to take the tools of

science that we have and say okay look

you know just carry the two and do a

triple integral here

ah and that is the the taste of feta

cheese or the smell of cinnamon or the

the pain of pain or the redness of red i

mean there's

there's no way to even quite see how to

take our current tools and translate it

private subjective experience yeah

because you mentioned

you mentioned in the book that you've

done experiments with colors

how do we know that when i'm looking at

blue

you're seeing the same color as i am

yeah we we have no way of knowing that

and it you know of course it doesn't

matter as long as you and i

can you know can both call something

blue because our mothers taught us to

call that

blue it doesn't matter if what you call

it is what i see is you know is red on

the inside

because we can transact and negotiate in

the in the outside world

and um you know i think it might even be

far worse than that i mean

what you call vision and what i call

vision might be very different and

years might be upside down from mine or

something and it wouldn't matter as long

as we can transact

and negotiate in the outside world what

i find interesting

is this issue about can we create

new senses for humans if anyone's

interested in this this is the uh

you can just find my ted talk online

where i go into more depth on this but

like with the vaster with the wristband

can we create new senses for humans

the interesting part is that if we did

that we wouldn't really be able to

communicate it to other people so let's

say matthew that you wear

a vest that communicates stock market

data so you start having an internal

subjective experience of the economic

movements of the planet

and i'm wearing a wristband that tells

me

infrared light and so i start having

a direct perceptual sense of the

infrared light that's around me

which is normally invisible the thing is

we couldn't communicate that to each

other because

language is all about shared notions

and um it's impossible to imagine what

another sense would feel like in the

same way

if i asked you imagine a new color

so you know take a moment think about

imagining a new color it's impossible to

do and what this illustrates is the

fence line

of our internal experience we cannot

ever imagine something that's outside of

the experience we've already

had so it may be that we end up you know

having to invent new words for these

things and only other people that are

wearing this would ever even have an

understanding of it

given that our brains as you explain are

changing and adapting the whole time

what are the implications of that for

identity

yeah you know this is uh

this is something i wrote a lot about in

my book some which is a book of fiction

but

one of the things that i'd love to

explore

is this issue of how we change through

time without really realizing that we're

changing so one of the stories

in the afterlife you're split into all

of your ages

and so um you know the expectation is

that it'll be really wonderful to

hang out with all your different ages

but it turns out the seven-year-old you

kind of likes hanging out with other

seven-year-olds and the 65 year old you

really wants to hang out with other

colleagues instead of and so

once a year all of the different use the

different ages of you get together for

like a family

reunion but um but you're not really the

same person at all

through life and because we have the

same

sort of history and resume you kind of

think that you're the same person but

because the brain is constantly changing

with every new experience you have

um you you drift you change through life

uh by quite a bit so i think these

things are really interesting in terms

of thinking about our identity

but it also has possible implications

for accountability

even for criminal responsibility because

if we're

fundamentally different beings or

characters to where we were 10 years ago

five years ago

for how long should we continue to be

punished

yeah the interesting part is you know

people go off on different trajectories

depending on

for better or worse you know their

childhood experiences i mean from the

moment they drop out of the womb

people end up going off on different

pathways and it is often the case

that somebody who's going on a

particular pathway

stays generally in that range so if they

committed this crime three years ago

they may still whatever was worrisome

about

their character that did it at the time

they may still have that quality

but um i deal a lot with the criminal

justice system i

actually am the director of the center

for science and law

and i all the time i mean i know several

people in prison who

have exactly the situation that you've

described which is they committed a

crime let's say 30 years ago and they

are clearly different now

they're clearly not the same person and

they

um you know just as one example uh a lot

of times with sex crimes

um you know as as a brain just simply

ages it becomes very different and is

not as driven as it was and so on

anyway um yeah this is something that

the legal system always has

to deal with it tends not to incorporate

neuroscience too deeply into it at the

moment but i'm trying to change that

it's impossible as you said a little

earlier to know how much we don't know

about the brain is it impossible

in a similar sense to know how much

of you david is nature and how much of

it is nurture

yeah it turns out the nature versus

nurture question

is actually a dead question in biology

now because it is always both

so you know you drop into the world with

a certain set of

genes and that prescribes you know the

the borders of what

can happen and then from there

your experiences lead you off on very

different pathways but there's

all this feedback by which i mean

there's a whole field called epigenetics

now which is how your experiences

will end up feeding back all the way to

your genome

and causing some genes to express more

and express

less and change the configuration of the

genome

and so your experiences actually change

what is getting expressed and so these

things are tied

too tightly together to ever separate

them and this is one of the themes of

the book also

is that when you look at something like

artificial intelligence

which is all the rage here in silicon

valley where i live um

you know what it's doing is it's taking

a very

sort of simplified notion of

neuroscience which is okay you've got

these

units that are connected with each other

and then it goes off in its own

direction and it's done some incredibly

impressive stuff

but it's actually nothing like the brain

i mean the brain

does incredibly impressive stuff that's

quite different as in a three-year-old

child

can walk into a room and navigate the

room and get food to her mouth and

manipulate adults and do all kinds of

things that

computers can't do any of that stuff

well

not even close and so you know plus

humans have generalized intelligence

which means we can do many things

whereas with an artificial neural

network

it can discriminate pictures of dogs and

cats with superhuman skill

but if you then ask it to do something

else like distinguished pictures of

you know camels and bears it fails

catastrophically so

anyway part of what this has to do with

is in an

artificial neural network you're just

changing the connection strength between

neurons

but in real brains you have changes not

only at the connection points but all

the way down

the receptors that are expressed in the

cell the biochemical cascades all the

way down to the genome

so you've talked several times already

about

you know dropping into the world so if i

were to be

be dropped into the caveman era as you

mentioned in the book

how different would i have been yeah

you know it's funny right the question

is the question that i posed is

what if you're born exactly your genome

you know exactly you you drop

you come out of the womb and you find

yourself you know 30 000 years ago

instead of now

um i think you'd be an extremely

different person

because it's all about experience what

is the experience that you

have that's what molds and shapes your

brain

and so anything we think about that like

oh i'd probably be

yeah i'd probably be i'd be like me but

running around in a pelt around the

campfire

not uh probably not the case because

experience is so important and by the

way we see this all the time

um with nature's tragic experiments

with um you know kids who are severely

neglected or

um i didn't talk about this in the book

but i just took about this in my show of

the brain

uh about the romanian orphanages which

after the fall of chuchu ended up with

tens of thousands of kids whose parents

had been killed

and um there were too many kids and so

the staff decided okay look

the only way we're going to be able to

do this is if we

um don't talk to the kids and we don't

pick up the kids and cuddle them and so

on because otherwise they'll become too

clingy and so they just didn't interact

with the kids and all these kids ended

up with severe cognitive deficits

because

what mother nature is doing is actually

a bit of a gamble which is i'm going to

drop a brain into the world

half baked and i'm going to assume that

the conditions of the world are enough

to

to form the brain appropriately but if

you're not getting the right input then

the brain doesn't develop correctly

in the book you describe the very

difficult challenging story of the

little boy

matthew who has half of his brain

removed you spoke in your little

presentation

about what can happen when half your

brain is removed and

he ended up developing into a normal

human being he works in a restaurant

he's able to do

much the same as all the rest of us are

capable of doing it's not exactly the

same things but then you give a very sad

example of a little girl

who was found after i think the first

seven years or so of her life

and and she'd been trapped in a cellar

with no human interaction or almost no

human interaction at all

her development subsequent to that

was was far more difficult yeah that's

exactly right i mean she

can't speak language she can't see more

than 13 feet she can't choose solid food

and you know even after years and years

of training and all these you know

psychologists and people and everybody's

caring for her

she still hasn't gotten language because

the brain has

these closing doors these critical

windows that you need to learn things

like

language within or else it becomes

too late and so yeah you can do just

fine if you're getting love with half a

brain

but you can't do well if you have a full

brain but are not getting

the uh the things that a child needs in

order to develop correctly

just to follow up briefly on this nature

nurture plus consciousness and

accountability

theme before moving on if we are no more

than the sum of our nature and our

nurture can we be properly accountable

for anything i mean to what extent are

we autonomous if we're being

shaped by our genetics and also by our

environments

where does sort of free will fit into

that yeah this is one of the big

questions in neuroscience is do we

have free will because when we look at

the brain it

is vastly complex as i mentioned but it

is fundamentally a machine it's a

biological machine where every neuron is

getting driven by the activity of other

neurons

and it's not clear where you get sort of

a puff of

this extra bit in there that causes what

would be free will as opposed to it

being a

machine so uh so this is a very tough

question as it turns out

from the legal system point of view it

actually makes no difference

uh whether people had the free will or

didn't have the free will

because you still have to take someone

who's acting aggressive and violent and

so on

and take them off the streets to protect

everyone else so um

but you know the key the key thing with

the legal system is to

figure out how to best manage things

moving forward so instead of imagining

that incarceration is the one size fits

all solution

one of the things that we're able to do

is say um

hey you know you you have a drug

addiction problem here's the way we can

help you instead of imagining that jail

is going to help

oh you have a mental illness in the

united states it's estimated that 30

percent of the prison population has

mental illness having them break rocks

in the sun doesn't

help schizophrenia so you need to have

clever ways of doing things and finding

treatment for people

um but it doesn't change the fact that

if they've committed a crime you still

have to take them off the street

tell us as you're doing the book a

little bit more about it it's an

important thing

the different speeds of learning

yeah yeah so this is the thing we

uh as i mentioned was talking about

artificial neural networks

the reason artificial neural networks

look just at the synaptic connection

strength

and we tend to do that in neuroscience

also we just concentrate on that

is because that's what we can most

easily measure and so what i

suggest in the book is it's like the

drunk looking for the keys under the

street light because that's where the

light is best but the fact is

we know that all these parameters all

the way down

are are changing and so you get all

kinds of

weird and interesting properties out of

that and um and i'm able to

you know explain how these things come

out i'll give you one example which is

there's something called ribose law

which is the oldest

principle in neurology actually which is

that older

memories are more stable than newer

memories which is very weird right

because

institutions don't work that way they

don't remember their older stuff better

than their newer stuff

but human brains do and so if any of you

know

maybe you've known an older person who's

getting dementia

you know they can't remember what they

did in the last week or last month or

last year but they remember their

childhoods just fine

and in fact um one of the stories i tell

us about albert einstein who

um nobody knows his last words because

on his deathbed he was speaking

in german his original language and the

night nurse didn't speak german so we

don't know what his last words were but

this is quite common where people revert

to their original language

as they're getting very old and they're

on their deathbed

and so what this demonstrates is that

you know

human memory the way we talk about it is

not like memory in a computer or in an

artificial neural network but instead it

has to do with

learning getting pushed all the way down

different levels different um you know

speeds of change all the way down and so

what i compare it to

is um in a in a city

you have all kinds of different speeds

of change so if you look at a city over

time you know their fashion is changing

rapidly

and then commerce and the stores that

are there is changing more slowly and

then governance how you pass laws for

the city is changing even more slowly

and the architecture is changing even

more slowly and all the way down to

nature

and it's sort of the same kind of thing

that you can do in the brain where you

have some parts that are changing really

fast

and some parts are changing slow and

it's all about the interaction of these

that matters

so with memory when there are things

that we

know have happened to us but we can't

remember but want to remember

what's going on there are they somewhere

buried deep in our brain do they

do they exist there if you've got your

your torch out

and you're a very very clever

neuroscientist would you be able to

locate those for me

yeah it's probably not um in the sense

that

what happens as things get deeper and

deeper is there's some amount of

abstraction that goes on which is

okay i remember that this person i

really like and this person over here i

really

am suspicious about but you you don't

have you ever found yourself in the

situation where you can't really

remember the details like

but you know i i met that person years

ago i remember why i like that person so

much or why i feel that person is creepy

or whatever

but it's because you've abstracted away

the details because

for almost all of us we can't possibly

remember all those details the reason i

say almost all of us is

there are people with essentially

perfect memories they're called

nemenists

and they have what's called

hyperthymesia which is they just they

encode everything but it's a very

unusual state and by the way they're not

they're not particularly

happy about it as an indian philosopher

once

said memories beautify life

but only forgetting makes it bearable

so what's happening with this memory or

this perception of memory that i have

this is the

weekend of the notting hill carnival i'm

in notting hill normally if it were not

a pandemic there'd be a million or two

million people on the streets

unfortunately one or two of them might

be urinating on my front yard but it's

basically a celebration

of west indian culture and it's great

fun and i love it now i can remember

i've been going for decades

and i can remember or believe i can

remember going on my father's shoulders

when i was two years old

is that a real memory or is that a

memory of a memory to what extent

are memories memories of memories yeah i

mean

memory is a myth making machine and

we're constantly reinventing our past to

make it consistent with who we think we

are

the general story is that boys don't lay

down memory till about three and a half

girls at about three is when your first

real memory is

but when i say real memory even that is

suspect i mean

memories drift and by the way a

colleague of mine did a great study

right after

september 11th 2001 she

interviewed a number of people in

midtown and downtown new york in other

words those who've been right there and

those who've been a little distance away

but anyway she asked people about their

memories in great detail about september

11th that morning

and then she also asked them to sell

some memory from september 10th

just some banal thing about what they

ate for breakfast and blah blah and then

she

tracked them down a year later and asked

them about both types of memory it turns

out

both memories had drifted completely so

even

uh you know what we call amygdala memory

memory that's

emotionally valenced um doesn't

everything drifts we uh yeah we're

constantly

we're storytellers but if you look at

the tyrolean iceman who pops up in the

book

your belief or your hunch is that we

might be able to return to this

thoroughly and i spent in the future and

by

studying the brain actually paint a

picture for ourselves of what his life

his life was was like yeah

exactly so so the argument i make there

is you know

everything that happens to you is

stored in the structure of your brain i

mean that's what it means to

experience the the smell of something or

recognize somebody or have a memory as

you know true or false as that memory is

um

and so if we could take an ancient brain

and actually this is not going to happen

in our lifetimes but

actually learn how to decode the

structure of this massive machinery

um we could in theory know what it was

like to be the tyrone iceman

and again this is not to say that the

memories would be accurate but but

nonetheless the

the smells the sights the the memories

that he had

irrespective of their accuracy and so on

we'd be able to read that out

one of my mentors was was uh the great

brit francis crick

and um when he died in 2006 uh he was

cremated and i thought

god what a waste like he was he was

probably the greatest brain of 20th

century biology

and then it just gets burned up and i

thought damn it if we could have just

somehow had the technology to retain

that so that 100 years from now when

we're able to read that out we could say

hey francis you know what's

what do you think of this and that now

our brains have to simplify things as

you've already intimated

in order for us to be able to function

properly and one of the ways

as i understand it or experience it that

the brain simplifies things is

through language so when we're reading a

word

we're looking at symbols but very very

quickly instantly almost

we're computing meaning from them if i

look at a language that is foreign to me

a ten letter word could take a second or

two

to compute even visually whereas if it

were a ten letter word in english

it would happen just like that so what's

going on there

yeah it turns out what we do is we

change our own circuitry to automatize

the tasks that are important to us so

for you reading english is really

important

so from the time you were a child you've

been drilling that into your head so now

what you have is

all this circuitry that is specialized

for reading the english language if you

grew up in china you'd have different

specialized circuitry just for reading

that sort of language

and when things become they sort of get

part of the circuitry the hardware of

the brain

they become fast and and effortless and

use very little

energy and so this is the game that the

brain is always playing is

how can i take the things that are in my

environment that i need to figure out

and make it so that it becomes part of

the machinery and i don't have to put

much effort into that and actually let

me just say one

tangential thing about this which is

despite how awful this uh

coronavirus lockdown is for everybody

um i think the one good silver lining

that comes out of this

has to do with brain plasticity which is

to say

we have grown up and we spent our whole

lives optimizing our brains to operate

in this world as we know it and suddenly

all of us are kicked off of our path of

least resistance we're all off of the

hamster wheel that we're used to

and we're having to be very creative and

think of things afresh

and you know there's plenty of stress

and anxiety that goes with this

but boy i think that is one of the best

things that can happen for the brain

is being forced to rethink everything um

and and build new bridges how

fundamentally and how quickly can we

change when we're in our 40s 50s 30s

once we

feel that we're pretty much fully

developed i mean i imagine

neuroscientists are fascinated by

how we're reacting and responding to

this pandemic

exactly right look one of the things

that i for that i suggest

in the book is that you know so we know

plasticity diminishes with age

but part of that has to do with

motivation which is to say

um as as we get into our 40s and we have

a really good model of the world and we

can optimize our functioning and say wow

i really got this

i've got my job i go to lab i go to my

company

this is cool there's less and less

relevance to changing that internal

model there's

there's no motivation for it but if we

are challenged

and we have to change our internal model

we are able to i mean there's

adult plasticity the brain can change in

an adult pretty easily

it's just that most of us never have

that opportunity to try

but one of the things that you find is

that um

you know when people retire for example

their lives tend to shrink

and uh and and dementia sets in

but there's been a a multi-decade study

going on about people who have been

cognitively active their whole lives up

to the day they die

they have all kinds of challenges and

things they have to do

even so some of them it turns out have

alzheimer's disease and their brain is

physically degenerating but even as

their brain is

generating they're constantly building

new roadways because of

challenging themselves to what extent is

it true that we

can train the brain as a muscle so that

by continuing to be cognitively active

as you describe

we're actually retaining more of our

brain function

yes i mean that is one that is probably

the most important lesson from modern

neuroscience is the

the critical nature of doing that which

is to say

keeping your brain challenged all the

time uh this is true for us but it's

especially true as people get older and

older

um and what that means is seeking novel

challenges things that are frustrating

but achievable

in that range and you know as soon as

you get good at something like sudoku or

whatever

drop that and pick up the next thing

that you're no good at

that's the key is to constantly

challenge the brain

this isn't entirely unrelated to the

reading of the language

question but when we talk of muscle

memory

so if you learn a martial art or if

you're a concert pianist

but it's extraordinary isn't it the

extent to which a concept pianist can

play at a ferocious pace

and you think the mind can't actively

surely

be triggering all those different finger

movements what's going on there to put

it simply

yeah well it's it's not actually muscle

memory even though we call it that it's

all in the brain it's all about the

brain re

you know reconfiguring its circuitry to

say ah okay rock monopoly piano concerto

bang here it is

it's getting burned all the way down to

the circuitry and so for the pianist

first learning how to play the rock

three it is

unbelievably challenging and takes a lot

of cognitive effort but after one

becomes you know

health god or you know uh ashkenazi you

just

um to call it muscle memory simply means

it's burned into the circuitry so

your conscious mind is no longer

involved in it at all it's just part of

your

operating system now i want you to tell

us a little bit more about

sleep and what's going on with our

brains at that point you talked earlier

about consciousness bubbling up as we

wake up

but rem sleep has a very important

function doesn't it

yeah and so this i mentioned in the talk

i think my

my hypothesis which i think is true now

we've published on this is that um

yeah is that rem dream sleep is all

about

just keeping the cortex active against

invasion

by by neighbors and generally sleep has

lots of functions

deep sleep which is different than dream

sleep deep sleep

has functions in terms of taking out the

neural trash and consolidating things

that were learned

during the day and so on there's a lot

of study on this um

currently there's sort of you know many

different um

functions of sleep that all seem to be

true at the same time

we're building on this though there's a

lot of competition going on inside our

brains

isn't there and i wonder how the brain

prioritizes on our behalf

the things that we really need to be

doing

yeah it doesn't do any prioritization it

has to do has everything to do with

uh the data that comes in so just as an

example if i

if i were to um if i were to anesthetize

my arm like let's say i put in a clamp

really tightly so

i or i inject it with an anesthetic

my brain maps will start to change

because it says oh i'm simply not

getting enough

data from the armor if i even tie two

fingers together so instead of acting as

two independent fingers

it's like one unit now um my brain maps

will actually

change so it's all about what's coming

in and as far as

other stuff it's all about what is

relevant what you get good

feedback on so uh so in the book i

propose what if there were a fictional

brother

to venus and serena williams named fred

williams

and he did just as much tennis practice

as they did

but for whatever reason he didn't like

it he didn't get

the positive feedback from relatives and

friends and whatever he wasn't motivated

to do tennis and whatever

what would happen his brain and the

answer is his brain would not

change in the same way venus and

serena's brains would be changing and

the reason is

you you need the positive feedback as a

way of changing the distribution of

territory but explain then what's

happening if it's not about

prioritization

when i'm speaking to you and we've got

hundreds of people

listening and watching so that's kind of

important you've definitely got my

attention i'm very focused on this

conversation but if

over the rim of my laptop i would see a

lion

rear its head outside my window unlikely

though that might be

i think i might become distracted from

our conversation so what what what

happens there in terms of prioritization

well

yeah great what you're talking about is

the attentional system and you've got

these very

deep systems we'd summarize that as the

limbic system

that is all about yeah is there an

emergency thing going on and that you

know you're constantly

re-um allocating your attention based on

priorities and so that's not so much a

brain plasticity issue as a very deeply

wired

fundamental thing about oh i'm in danger

and all your attention goes there but

isn't it interesting though david that

given the sophistication of our brains

so sophisticated that

even our own brains don't understand how

much more there is to understand about

them

sort of paradox yet at the same time we

as human beings are notorious

for being very very poor poorly equipped

to deal with

more than two kind of big thoughts or

big ideas

or big attention grabbers at the same

time so at the moment we're absolutely

focused on the pandemic

yet climate change is roaring up on the

horizon

so why are we so simplistic and yet so

complex at the same time

this has to do with the funnel of

consciousness so you've got this entire

cosmos going on inside your head

but you know your consciousness has a

very low bandwidth and so can only think

essentially one

thought at a time and fundamentally

we are creatures that have grown up in

small groups and we have very basic

sorts of

needs and wants and desires and so what

you care about is

what's my next meal who's my mate what's

going on with you know the next thing

and so

um you know bigger issues going on in

the world are

hard to hold on to and stay

invested in because you've got other

more local needs going on because that's

just the kind of creatures that we are

um i've got to prioritize the questions

i ask you because we haven't got a huge

amount of time

left and i want to bring in some q a

questions as well

describe to us briefly if you would in

the most broad sense the power of the

mind

over the body the mind can play tricks

on us as you as you say

but when we we can go as far as say to

imagine symptoms of

physical illness or weak perhaps or we

can correct me if i'm

i'm wrong or we can manifest physic

physical signs of distress as a result

of what's going on in our brain

yeah the brain and the body of course

are tied very tightly together

um and some people even point to you

know oh well is the gut involved and how

we think and so um the general story on

this

is that the brain is the densest

representation of who you

are it's like the the metropolitan

center and this is

the body is let's say the greater

metropolitan area but there's plenty of

interaction and communication between

those and so it's no surprise that we

show all kinds of physical symptoms with

things as far as the power

of the mind over the body that is

unfortunately limited i mean if you get

skin cancer in your leg you're not going

to be able to think your way out of that

one

it's just um yeah there's there's uh

unfortunately there's so much in biology

that our minds

can't uh accomplish that way

sorry when we typically hear about

people fighting

or or struggling against cancer or

another disease

is that unfair i mean often people who

suffer from those diseases themselves

talk about the fight that they're

engaged with but can

the mind help us to get better i mean

you can't wish away cancer but can you

fight it

yeah uh unfortunately it does not seem

so i mean every single

person who's had cancer uh has died has

as has ever

what i mean is even the most optimistic

buddhist monk or whatever

they all everybody dies and so um

that tells us that it's not something

that you can just use the mind to

override the body

on that stuff when when people talk

about struggling with cancer and

struggling against it

i think most of what they're talking

about is a psychological thing like how

do i

put aside my grief and how do i

communicate with my family well

and how do i stay optimistic about

things but

they're not actually fighting the cancer

itself they're fighting all the

psychological warfare around it

final quick question for me before the q

a how do you see

gertrude the pig and the future do you

believe that we will get to a point

where we start inserting chips into our

brains so that we can turn the telly on

and off

you're referring to the neural link

presentation the other day yeah the

yeah so for anyone who doesn't know uh

yeah elon musk's

new company is neural link where they

drill a hole in the head and they insert

electrodes

what's just one second thing on that um

inserting electrodes into the brain to

be able to measure from neurons

there's nothing new about that that's

been happening for at least 50 or 60

years but

the um but what what he and his team

have developed is a way of sort of

sowing electrodes in there so you get a

higher density so they can read

let's say a thousand different neurons

activity

uh without hitting any blood vessels

it's it's it's quite cool

um but it's just a different degree of

what we've been doing but

um the question is will consumers go for

that that

was sort of always the shtick around

neural link is wow everybody will get

that here's what i think in one sentence

which is that

it's going to be very useful for

clinical

states as in you know with major

depression or parkinson's or epilepsy

and you know this idea of just getting a

better density of electrodes in there

will it ever get to the point where

consumers use it to interact with their

phone faster i doubt it and here's why

it's because it's an open head surgery

and surgeons aren't going to do it

because there's always risk of infection

and death on the table

and it's just not worth the risk in

order to be able to uh interact better

with your computer

joel wants to ask you david says my

stepfather's 88 has taken on lots of new

habits

and interests around poetry and

literature after my mother's death

and he said he thought that his brain

had changed is this possible so late in

life it plays back into a question

earlier on in that conversation

sure yeah i mean there's anal plasticity

and if you're challenging yourself like

really appropriately challenging

yourself

again as soon as you get good at

something dropping that picking out

something that you're no good at

then yes that is exactly what happens

how do we says marek how do we

reconcile the amazing examples of

plasticity

with the failure of the brain to recover

from for example a hard blow to the head

yeah um one of the studies that i talk

about in the book is

um after world war ii there were a

number of people with

head injuries and so a scientist in the

70s

tracked down a whole bunch of these

soldiers who had now grown up to see how

they were faring and what he found

pretty clearly was that the younger you

are when you get the head injury the

better off you are

the older brain gets the less flexible

it is

and it's for this reason that i

mentioned before which is that you've

been

learning the world and as you've been

learning the world you've cemented more

and more

tightly into place and so then when

something gets damaged it's

it's harder to find room to move around

but the

younger you are the moon you have to do

that

and michelle says when you spoke about

why we dream

does that mean that the people who have

permanently lost their vision

do not dream and and that's not an

entirely different different question to

jill so he says does a blind person