Kind: captions
Language: en
the following is a conversation with
lisa feldman barrett
a professor of psychology at
northeastern university
and one of the most brilliant and bold
thinkers and scientists i've ever had
the pleasure of speaking with
she is the author of a book that
revolutionized our understanding of
emotion in the brain
called how emotions are made and she's
coming out
with a new book called seven and a half
lessons about the brain
that you can and should pre-order now
i got a chance to read it already and
it's one of the best
short whirlwind introductions to the
human brain i've ever read
it comes out on november 17th but again
if there's anybody worth supporting it's
lisa so please do pre-order
the book now lisa and i agreed to speak
once again
around the time of the book release
especially because we felt that this
first conversation is good to release
now since we talk about the divisive
time we're living through in the united
states
leading up to the election and she gives
me a whole new way to think about it
from a neuroscience perspective
that is ultimately inspiring of empathy
compassion
and love quick mention of each sponsor
followed by some thoughts related to
this episode
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to support this podcast as a side note
let me say that the bold first
principles way that lisa
approaches her study of the brain is
something that has inspired me ever
since i learned about her work
and in fact i invited her to speak at
the agi
series i organized at mit several years
ago
but as a little twist instead of a
lecture we did a conversation in front
of the class
i think that was one of the early
moments that led me to start this
very podcast it was scary and gratifying
which is exactly what life is all about
and it's kind of funny how
life turns a little moments like these
that at the time don't seem to be
anything out of the ordinary if you
enjoy this thing subscribe on youtube
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friedman and now here's my conversation
with lisa feldman barrett since we'll
talk a lot about the brain today do you
think
let's ask the craziest question do you
think there is other intelligent life
out there in the
universe honestly i've been asking
myself lately if there's intelligent
life on this planet
uh you know i ha i i have to
think probabilities suggest yes and
also secretly i think i just hope that's
true
it would be really um i know scientists
aren't supposed to have hopes and dreams
but
uh i i think it would be really cool and
i also
think it would be really sad if it if it
wasn't the case if we really were alone
that would be
that that would seem
profoundly sad i think so it's exciting
to you not scary
yeah no you know i take a lot of comfort
and curiosity
it's a great it's a great um
resource for dealing with uh stress
so um i'm learning all about mushrooms
and
uh octopuses and you know all kinds of
stuff
um and so for me this counts i think in
the
realm of awe but also i think i'm
somebody who
cultivates awe deliberately on purpose
to feel like a speck
you know i i find it a relief
occasionally it feels small to feel
small
in a profoundly large and interesting
universe
so maybe to dig more technically
on the question of intelligence do you
think it's difficult for intelligent
life to arise like it did on earth
from everything you've written and
studied about the brain
how magical of a thing is it
in terms of the odds it takes to arise
yeah so you know magic is just
don't get me wrong i mean i like i like
a magic shirt as much as the next person
my husband was a magician at one time
but
you know magic is just a bunch of stuff
that we don't really understand how it
works yet so i would say from what i
understand
there are some major steps in the course
of evolution that at the beginning of
life
the step from single cell to
multicellular organisms things like that
which are
really not known i think for me the
question is not so much um
could it you know what's the likelihood
that it would happen again
as much as um
what are the steps and how long would it
take and if it were to happen again on
earth
would would we end up with the same
you know menu of life forms that we
currently have now and i think the
answer is probably no
right there's just so much about
evolution that is stochastic and
driven by chance but the question is
whether that menu would be equally
delicious
meaning like there'd be rich complexity
of the kind of
like would we get dolphins and humans or
whoever else falls in that category of
weirdly intelligent
seemingly intelligent however we define
that
well i think that has to be true if you
just look at the range of creatures
who've gone extinct
i mean but if you look at the range of
creatures that are on the earth now it's
incredible
and you know it's sort of tried to say
that but it actually is really
incredible
um particularly i don't know i mean
animals there are animals that seem
really ordinary
until you watch them closely and then
they become miraculous you know like
certain types of birds
which do very miraculous things uh
um build you know bowers and do dances
and all these really funky things that
are hard to explain uh with a standard
evolutionary story although
you know um people have them birds are
weird they do a lot of for mating
purposes
they they have a concept of beauty
i haven't quite maybe you know much
better but it doesn't seem to fit
evolutionary arguments well it does fit
well it depends right so
i think you're talking about the
evolution of beauty the um
book that was written recently by was it
from
um without his name richard from i think
no i didn't oh it's a great book it's
very controversial though because
he is argues make an argument that
the the question about birds and some
other animals is why would they
engage in such metabolically costly
um displays when it doesn't improve
their fitness at all
and the answer that he gives is the
answer that darwin gave
which is sexual selection um not natural
selection but you know
selection can occur for all kinds of
reasons there could be artificial
selection
which is when we breed animals right
which is actually
how darwin that that observation helped
darwin come to the idea of natural
selection
oh interesting um and then there's
sexual selection
um meaning and the argument that that um
i think his name is from
uh makes is that um that it's the
pleasure the selection pressure is the
pleasure of female birds
which as a woman and um as someone who
studies affect that's a great
answer i actually think there probably
is natural i think there is an aspect of
natural selection to it which he maybe
hasn't considered
but you were saying the reason we
brought up birds is the
the life we got now seems to be quite
yeah so you
peek into the ocean peek into the sky
there are miraculous creatures
look at creatures who've gone extinct
and
you know in science fiction uh stories
you couldn't dream up something as
interesting so my guess is that
you know intelligent life evolves in
in many different ways even on this
planet uh there isn't one form of
intelligence there's not one brain that
gives you intelligence
there are lots of different brain
structures that can give you
intelligence
so my guess is that the
menagerie might not look exactly the way
that it looks now but it would certainly
be
as as interesting but if we look at
the human brain versus the brains or
whatever you call them
the mechanisms of intelligence in our
ancestors even early ancestors
that you write about for example in your
new book
what what's the difference between
the the fanciest brain we got which is
the human brain
and uh the ancestor brains that it came
from
yeah i think it depends on how far back
you want to go
you go all the way back right in your
book
so what's the interesting comparison
would you say well first of all i
wouldn't say that the human brain is the
fanciest brain we've got
i mean an octopus brain is pretty
different and pretty fancy and they can
do some pretty
amazing things that we cannot do you
know we can't grow back limbs we can't
change color and texture we can't
comport ourselves and squeeze ourselves
into a little crevice
i mean these are things that we invent
these are like superhero abilities that
we invent in stories right we can't do
any of those things
and so the human brain is certainly um
we can certainly do some things that
other animals can't do
that seem pretty impressive to us but
but
i would say that there there are a
number of animal brains which
seem pretty impressive to me that can do
interesting things and
really impressive things that we can't
do i mean with your work on how emotions
are made and so on you
you kind of repaint the the view of the
brain
as um as less glamorous
i suppose than you would otherwise
think or like i guess you draw a thread
that connects all brains
uh together in terms of homeostasis and
all that kind of stuff
i yeah i wouldn't say that the that the
human brain is
any less miraculous than anybody else
would say
i just think that there are other brain
structures which are also miraculous
and i also think that there are a number
of things about the human brain which
we share with other other vertebrates
other animals with backbones
but um that are that we share these
miraculous things but we can do
some things in abundance and we can also
do some things
with our brains together working
together that other animals
can't do or at least we haven't
discovered their ability to do it
yeah this social thing how i mean that's
one of the things you write about
uh what's uh how do you make sense
of the fact uh like the book sapiens and
the fact that we're able to kind of
connect like network our brains together
like you write about i'll try i'll try
to stop saying that
uh is that is that like some kind of
feature
that's built into there is that unique
to our human brains like how do you make
sense of that
what i would say is that our ability to
coordinate with each other is not unique
um to humans there are lots of animals
who can do that and we um
but what we do with that coordination
is unique because of some of the
structural features
in our brains and
it's not that other animals don't have
those structural features
it's we have them in abundance so
you know the human brain is not larger
than you would expect it to be for a
primate of our size
if you took a chimpanzee and you
ex grew it to the size of a human
that chimpanzee would have a brain that
was the size of a human brain
so there's nothing special about our
brain in terms of its size
there's nothing special about our brain
in terms of
the um the basic blueprint that
builds our brain from an embryo is the
basic blueprint that builds all
mammalian brains and maybe even all
vertebrate brains
um it's just that because of its size
and particularly because of the size of
the cerebral cortex which is the
um a part um that people mistakenly
attribute to rationality yeah mistakenly
is that
where all the clever stuff happens well
no it really isn't
and i will also say that lots of clever
stuff happens in animals who
don't have a cerebral cortex but right
um but
uh but because of the size of the
cerebral cortex
and because of some of the features that
are enhanced
by that size that gives us the capacity
to
do things like build civilizations um
and coordinate with each other not just
to
manipulate the physical world but to add
to it
in very profound ways like you know
other animals can cooperate with each
other and use tools
um we draw a line in the sand and we
make countries and we even then we
create you know uh we create citizens
and immigrants
but also ideas i mean the countries are
centered around the concept of
like ideas well my well what do you
think a citizen is and
and an immigrant those are ideas those
are ideas
that we um impose on reality and make
them real
and then they have very very serious and
real effects
physical effects on people what do you
think about the idea
that a bunch of people have written
about dawkins with memes
which is like ideas are breeding like
we're just like the canvas for ideas to
breed
in our brains so this kind of network
that you talk about of brains
it's just a little canvas for ideas to
then yeah eat against each other and so
on i
i think it's a rhetorical tool it's cool
to
uh think you know think that way so um i
think it was michael pollan
i don't remember if it was in the botany
of desire but it was in one of his early
books on um on botany
and gardening where he wrote about
um and he wrote about uh you know
plants sort of utilizing humans for
their own
you know evolutionary purposes which is
kind of interesting you can
think about a human gut in a sense as a
propagation device for the seeds of you
know tomatoes and what
what have you so it's kind of cool um so
i think
i think rhetorically it's an interesting
device but you know
ideas are as far as i know
invented by humans propagated by humans
um so you know i i don't think they're
separate from human brains in
in any way although it would it is
interesting to
to think about it that way well of
course the ideas that are using your
brain
to communicate and write excellent books
uh and they basically picked you
uh lisa as an effective communicator
and and thereby are winning so that's an
interesting world view
to think that there's particular aspects
of your brain
that are conducive to certain sets of
ideas
and maybe those ideas will win out yeah
i think the way that i would say it
really though is that
there are many species of animals that
influence each other's nervous systems
that regulate each other's nervous
systems
and they mainly do it by physical means
they do it by
chemicals scent they do it by you know
so
so termites and ants and bees for
example
use chemical scents mammals like
um like rodents use scent and they also
use uh hearing audition and that little
bit of vision
um primates you know non-human primates
add vision
right and
i think everybody uses touch humans as
far as i know are the only species that
use
ideas and words to regulate each other
right
i can text something to someone halfway
around the world
they don't have to hear my voice they
don't have to see my face
and i can have an effect on their
nervous system and
ideas the ideas that we communicate with
words
i mean words are in a sense a way for us
to do mental telepathy with each other
right i mean i'm not the first person to
say that obviously but
how do i control your heart rate how do
i control your breathing how do i
control your actions
with words it's because those words are
communicating ideas
so you also write i think let's go back
to the brain
you write that plato gave us the idea
that the human brain has
three brains in it three forces
which is kind of a compelling notion uh
you disagree
first of all what are the three parts of
the brain
and uh why do you disagree
so plato's description of the psyche
which for the moment we'll just assume
is the same as a mind
there are some scholars who would say
you know a soul a psyche a mind
those aren't actually all the same thing
in ancient greece but we'll just
for now gloss over that so plato's idea
was that
and it was a it was a description of
really about moral behavior and moral
responsibility in humans
so the idea was that you know the human
psyche can be described with an
um a metaphor of
two horses and a charioteer so one horse
for instincts like
feeding and fighting and fleeing and
reproduction i'm trying to control my
salty language
which apparently they print in england
like i actually tossed off of
f s yeah f f okay yeah yeah i was like
you printed that i couldn't believe you
printed that
without like the stars or whatever no no
no there was full print
yeah they also printed the a b word and
it was really
quite yeah anyways we should we should
uh learn something from england
indeed anyways but instincts and then
the other horse
represents emotions and then the cherry
tier represents rationality which
controls
you know the two beasts right and
um fast forward you know
couple of centuries and uh
in the middle of the 20th century there
was a very
popular view of brain evolution which
suggested that you have this uh
reptilian core like a lizard bra an
inner lizard
brain for instincts and then wrapped
around that
evolved on layer on top of that evolved
a limbic system
for uh in mammals so the novelty was in
a mammalian brain
which uh bestowed mammals with uh gave
them emotions the capacitive emotions
and then um on top of that
uh evolved uh a cerebral cortex
um which in
in largely in primates but but very
large
in in humans um and
it's not that i personally disagree
it's that as far back as the 1960s but
really by the 1970s it was shown pretty
clearly
with evidence from molecular genetics so
peering into
cells in the brain to look at the
molecular makeup of genes that the brain
did not evolve that way
and the irony is that
um you know the the idea of the
the three-layered brain with an inner
lizard you know that
hijacks your uh hijacks your behavior
and causes you to do and say things
that uh you would otherwise not or maybe
that you will regret later
that idea um became
very popular was popularized by
uh carl sagan in the dragons of eden
which won a pulitzer prize
in 1977 when it was already known pretty
much
in evolutionary neuroscience that the
whole uh narrative was a myth
so well the narrative is on the the way
it evolved but do you
i mean again it's that problem of it
being a useful
tool of conversation to say like there's
a lizard brain
and there's a like if i get overly
emotional on twitter
that was the lizard brain and so on uh
but do you no i don't think it's useful
i think it's a
i think that is it is is it uh is it
useful is it accurate
i don't think it's accurate and
therefore i don't think it's useful
so i here's what i would say you know i
think that
um the way i think about
philosophy and science
is that they are useful tools for living
and in order to be useful tools for
living
they have to
help you make good decisions
the try and brain as it's called this
this three-layer brain the idea that
your brain is like an already baked cake
in and you know the cortex cerebral
cortex is just layered on top like icing
the idea that idea is the foundation
of the law in
most western countries it's the
foundation of uh
economic theory and it
largely and it's a great narrative it
sort of fits our
intuitions about how we work but it also
um it's in addition to being wrong
it lets people off the hook for uh
for nasty behavior you know um
and it also suggests that emotions can't
be a source of wisdom
which they often are in fact you
you would not want to be around someone
who didn't have emotions that would be
that's a psychopath right i mean that's
not someone you
you know want to want to really uh have
have that person deciding your outcome
so i guess my
and i could sort of go on and on and on
but my point is that
um i don't think
i don't think it's a useful narrative in
the end
what's the more accurate view of the
brain that we should use when we're
thinking about it
i'll answer that in a second but i'll
say that even our notion of what an
instinct is or what a reflex is is not
quite right right so if you look at
evidence
from um ecology for example and you look
at animals in their ecological context
what you can see is that even things
which are
reflexes are very context-sensitive
um the the brains of those animals are
executing
so-called instinctual actions in a very
very context-sensitive way
and so you know even when
a physician you know takes the you know
it's like the idea of your patellar
uh reflex where they hit you know your
patellar tendon on your knee
and you you kick the the force with
which you kick
and so on in is influenced by all kinds
of things it's it's
a reflex isn't like a robotic
uh response and um
so i think a better way is a way that
to think about how brains work is the
way that um
matches our best understanding our best
scientific understanding which i think
is
really cool uh because it's really
counterintuitive so how i came to this
view
and i'm certainly not the only one who
holds this view i was reading
work in on neuroanatomy and the
the view that i'm about to tell you was
sugges strongly suggested by that and
then i was reading work and signal
processing like by engineer electrical
engineering
and similarly it the work suggested
that that the research suggested that
the brain worked this way and
i'll just say that i was reading across
multiple literatures and they were
who don't speak to each other and they
were all pointing in this direction
and so far although some of the details
are still
up for grabs the general gist i think is
i've not come across anything yet which
really violates and i'm looking um
and so the idea is something like this
it's very counterintuitive
um so the way to describe it is to say
that your brain doesn't react to things
in the world
it's not it to us it feels like our eyes
and our um
our windows on the world we see things
we hear things
we we react to them um in psychology we
call this stimulus response
so your face is your voice is a stimulus
to me
i receive input and then i react to it
uh and i might react very automatically
you know system one uh and uh oh
but i also might execute some control
where i
maybe stop myself from saying something
or doing something
and um more in a more reflective way
execute a different action right that's
system two
the way the brain works though is it's
predicting all the time
it's constantly talking to itself
constantly
uh talking to your body uh and it's
constantly
um predicting what's going on in the
body and what's going on
in the world and making predictions and
the information from your body and from
the world really
confirm or correct those predictions so
fundamentally the thing
that the brain does most of the time is
just
predict like talking to yourself and
predicting stuff about the world not
like this dumb thing that just senses in
response senses
yeah so the way the way to think about
it is like this you know your brain is
uh trapped in a dark silent box yeah
that's very
romantic of you um which is your skull
and the only information that it
receives
from your body and from the world right
is through the senses through the sense
organs
your eyes your ears and you have
a sense sensory data that comes from
your body
that you're largely unaware of uh to
your brain which we call interroceptive
as opposed to exteroceptive which is the
world around you
and but your brain is receiving
sense data continuously
which are the effect of some set of
causes
your brain doesn't know the cause of
these
sense data it's only receiving the
effects of those causes which are the
data themselves
and so your brain has to solve what
philosophers call an inverse inference
problem
how do you know when you only receive
the effects of something how do you know
what caused those effects so
when there's a flash of light or a
change in air pressure
or a tug somewhere in your body
how does your brain know what caused
those
events so that it knows what to do next
to keep you alive and well
and the answer is that your brain has
one other source of information
available
to it which is your past experience
it can reconstitute in its wiring
past experiences and it can combine
those past experiences
in novel ways and so
we have lots of names for this in
psychology we call it memory
we call it perceptual inference we call
it simulation
it's also we call it concepts or
conceptual knowledge
we call it prediction basically if we
were to
stop the world right now stop time
your brain is in a state
and it's representing
what it believes is going on in your
body and in the world
and it's predicting what will happen
next
based on past experience right
probabilistically what's most likely to
happen
and it begins to
um prepare
your action and it begins to
prepare your the prepare your experience
based so it's anticipating the sense
data it's going to receive
and then when that those data come in
they
either confirm that prediction and your
action executes
because the plan has already been made
or
um it where there's some uh sense data
that your brain
didn't predict that's unexpected and
your brain takes it in
we say encodes it we have a fancy name
for
that we call it learning your brain
learns
and it updates its storehouse of
knowledge which we call an
internal model and uh that you so that
you can predict better next time
and it turns out that predicting and
correcting predicting and correcting
is a much more metabolically efficient
way to run a system
than constantly reacting all the time
because if you're constantly reacting it
means you have no
you can't anticipate in any way what's
going to happen and so the
the amount of uncertainty that you have
to deal with is
uh overwhelming to a nervous system
metabolically costly i like it
and so what is a reflex a reflex is when
your brain doesn't check against
the sense data that the potential cost
to you is so great maybe because
you know your life is threatened that
your brain
makes the prediction and executes the
action
without checking yeah so but prediction
is still at the core that's a beautiful
vision of the brain i wonder
from almost an ai perspective but just
computationally
is the brain just mostly a prediction
machine then
like is the perception just the
nice little feature added on top like
the
both the the integration of new
perceptual information
i wonder how big of an impressive system
is that relative to just the big
predictor model construction well i
think that we can
we can look to evolution for that for
one answer
which is that when you go back you know
550 million years give or take
we you know the world was populated by
creatures really ruled by creatures
without brains
um and um you know that's a biological
statement
not a political statement really world
war ii
dinosaurs dumb you're talking about like
oh no i'm not talking about dinosaurs
honey i'm talking
way back further back than that um
really these they're these little
little um creatures called uh amphioxus
which is the modern
it's a or a lancet that's the modern
animal
but it's an animal that scientists
believe is very similar
to um our common the common ancestor
that we share
uh with invertebrates um because
uh basically because of the tracing back
the molecular genetics and cells
and that animal had no brain
it had some cells that would later turn
into a brain but in that animal there's
no brain but that animal also had no
head
and it had no eyes and it had no ears
and it had really
really no senses for the most part it
had
very very limited sense of touch it had
an eye spot for um not for seeing but
just for
um in training to circadian rhythm to
light and dark
and it had no hearing it had a
vestibular cell
so that it could keep upright in the
water
at the time approx we're talking
evolutionary scale here so
you know give or take some 100 million
years or something
but at the time you know what are the
vertebrate like when of when a backbone
evolved
and a brain evolved a full brain
that was when a head evolved with sense
with
sense organs and when um that's when
your viscera like internal systems
involved so
the answer i would say is that um that
senses
nurse motor neuroscientists people who
study the control of motor behavior
believe that senses evolved in the
service of motor action
so the idea is that like
what triggered the what triggered what
was what was the big evolutionary change
what was the big
pressure uh that made it useful
to have eyes and ears and a visual
system and an auditory system and a
brain basically and
you know and the answer that um is
you know commonly entertained right now
is that it was predation
that when at some point an
animal evolved that deliberately ate
another animal
and this launched an arms race between
predators and prey
and it became very useful to have senses
right so these these little antioxidants
these little amphioxy
you know don't really have they
they don't have an um they're not aware
of their environment very much
really they um uh
and so being able to
look up ahead and you know
ask yourself you know is that you know
should i eat that or will it eat me
um is is a very useful thing so the idea
um is that sense sense sense data
is not there for consciousness it didn't
evolve for the purposes of consciousness
it didn't evolve for the purposes of
experiencing anything
um it evolved uh in the cert
to be in the service of motor control
however
maybe it's useful um this is why
you know scientists sometimes uh
avoid questions about why things evolved
that this is what
philosophers call this teleology you
might be able to say something about
how things evolve
but not necessarily why we don't really
know the why
that's all speculation but the y is kind
of nice here this
the interesting thing is uh that was the
first
element of social interaction is am i
gonna eat you or are you gonna eat me
and for that
it's useful to be able to see each other
sense each other
that's kind of fascinating that there
was a time when life didn't eat each
other
or they did by accident right so an
amphioxus for example
well um it kind of like gyrates in the
water
and then it plants itself in the sand
like a blade of like a living blade of
grass and then it just
filters uh whatever comes into its mouth
right so it is it is eating but it's not
actively
hunting and when um
the concentration of food decreases
it the amphioxus can sense this
and so it basically wriggles itself
randomly to some other spot which
probabilistically will have more food
than wherever it is
so it's not really you know it's not
guiding its actions
um on the basis of it's not we would say
there's no real intentional action
um in that in that in the traditional
sense speaking of intentional action
and if the brain is put if prediction is
indeed
a core component of the brain let me ask
you a question that scientists also hate
is uh about free will so how does uh
do you think about free will much how
does that fit into this
into your view of the brain why does it
feel like
we make decisions in this world this is
a hard q a
scientists hate this because it's a hard
it's a hard question we don't know
they're taken aside
i think i have free will i think i have
taken aside but it it
i don't put a lot of stock in my own
intuitions or anybody's intuitions about
the cause of things right our ex
one thing we know about the brain for
sure is that the brain creates
experiences for us
my brain creates experiences for me your
brain creates experiences for you
in a way that lures you to believe that
those experiences
actually reveals the way that it works
right but it doesn't
so so you don't trust your own intuition
about
not really not really no i mean no but
but i am
also somewhat persuaded by you know i
think dan dennett wrote at one point
like um uh you know the philosopher dan
dennett wrote at one point that
um it it's i can't say it as eloquently
as him but it
people obviously have free will they are
obviously making choices so
it's you know and so there is this
observation
that we're not robots and we can do some
things like a little more sophisticated
than an amphioxus so
um so here's what i would say i would
say
that your predictions your internal
model
that's running right now right that your
ability to
understand the sounds that i'm making
and attach them to ideas
is based on the fact that you
have years of experience knowing what
these sounds mean in a particular
statistical uh pattern
right i mean that's how you can
understand the words that are coming out
of my
mouth right i think we did this once
before too didn't we when we were
i don't know i would have to access my
memory module i think when i was in your
glen classic yeah i think we did it just
like that actually so bravo
wow yeah i have to go look look back to
the tape
yeah anyways the um the idea though
is that your brain is using past
experience and it can
and it can use past experience in um
so it's remembering but you're not
consciously remembering it's basically
re-implementing prior experiences
as a way of predicting what's going to
happen next and it can do something
called conceptual combination which is
it can take bits and pieces of the past
and combine it in new ways
so you can experience and make sense of
things that you've never encountered
before because you've encountered
something
similar to them
um and so a brain
in a sense is not um
just um doesn't just contain information
it is information gaining meaning it can
create it new information
by this generative process so in a sense
you could say well that maybe that's
that's a source of free will but i think
really where free will comes from or the
kind of free will that i think is worth
having a conversation about is um
involves cultivating experiences for
yourself
that change your internal model
when you were born and you were raised
in a particular
context that your mod your brain wired
itself
to your surroundings to your physical
surroundings and also to your social
surroundings
so you were handed an internal model
basically
um but uh when you grow up
the more control you have over your
where you are and what you do um
you can cultivate new experiences for
yourself and those new experiences
can change your internal model and you
can actually
um practice those experiences in a way
that makes them automatic meaning it
makes it easier for the brain
your brain to make them again and
i think that that is something like
what you would call free will you aren't
responsible
for the model that you were handed that
someone you know your your caregivers
uh cultivated a model in your brain
you're not responsible for that model
but you are responsible for the one you
have now
you can choose you choose what you
expose yourself to
you choose uh how you spend your time
not everybody has choice over everything
right but everybody has a little bit of
choice
um and and so i think
that is uh something that i think is
arguably called free will
yeah there's this like the the ripple
effects of the
billions of decisions you make early on
in life
have are so great
that uh even if it's not
even if it's like all deterministic just
the amount of possibilities that are
created and then the focusing of those
possibilities into a single trajectory
uh that somewhere within that that's
free will even if it's all deterministic
that might as well be
of just the number of choices that are
possible and the fact that you just make
one
trajectory to those set of choices seems
to be like
something like they'll be called free
will but it's still kind of sad to think
like
there doesn't seem to be a place where
there's magic in there
where it is all just a computer well
there's lots of magic
i would say so far because we don't
really understand
uh how all of this is exactly
played out at a
i mean scientists are working hard and
disagree
about some of the details under the hood
of what i
just described but i think there's quite
a bit of magic actually and also there's
there's also um stochastic
firing of neurons don't they
they're not purely digital in the sense
that
there is there's also analog
communication between neurons not just
digital
so it's not just with not just with
firing of axons
and some of that there's there are other
ways to communicate and
also um uh
there's noise in the system and the
noise is there
for a really good reason and that is the
more
variability there is the more
potential there is for your brain to
be able to be information bearing so
um basically you know there are some
animals that
have clusters of cells the only job is
to inject noise
you know into their um neural patterns
so maybe noise is the source of free
will
so you can think about you can think
about stochasticity or noise as
as a source of free will or you can
think of
of um conceptual combination as a source
of free will
you can certainly think about um
cultivating uh
you know you can't reach back into your
past and
change your past you know people try by
psychotherapy and so on but
what you can do is change your present
which becomes your past
right think about that sentence so one
way to think about it is that you're
continuously this is a colleague of mine
a friend of mine said so what you're
saying is that people are continually
cultivating
their past and i was like that's very
poetic
yes you are continually cultivating your
past
as a means of controlling your future
so you think uh yeah i guess the the
construction of the mental model that
you use for prediction
ultimately contains within it your
perception of the past like the way
you interpret the past or even just the
entirety of your narrative about the
past
so you're constantly rewriting the story
of your past
oh boy yeah that's one poetic and also
just awe inspiring
what about the other thing you talk
about
you've mentioned about sensory
perception as a thing that like
is just you have to infer about the
sources
of the thing that you have perceived
through your senses
so uh let me ask the
another ridiculous question is is
anything real at all
like how do we know it's real how do we
make sense
of the fact that just like you said
there's this brain sitting alone in the
darkness trying to perceive the world
how do we know that the world is out
there i
will be perceived yeah so i don't think
that you should be asking questions like
that without passing a joint
right no for sure yeah i actually did
before this so i apologize
okay no well that's okay you apologize
for not sharing that's okay
so i mean here's what i would say what i
would say is that the reason why
we can be pretty sure that there's a
there there is that
the the structure of the information in
the world
what we call statistical regularities in
sights and sounds and so on
and the structure of the information
that comes from your body it's not
random stuff
there's a structure to it there's a
spatial structure and a temporal
structure
and that spatial and temporal structure
wires your brain
so an infant brain is not a miniature
adult brain
it's a brain that is waiting for wiring
instructions from the world
and it must receive those wiring
instructions
to develop in a typical way so for
example
when a newborn is born when a newborn is
born when a when a baby is born um
the baby can't see
very well because the visual system in
that baby's brain
is not complete the
the retina of your eye which actually is
part of your brain
has to be stimulated with photons of
light if it's not
the baby won't develop normally to be
able to see
in in a neurotypical way same thing is
true for hearing
the same thing is true really for all
your senses so the
point is that that
the physical world the sense data from
the physical world
wires your brain so that you have an
internal model
of that world so that your brain can
predict well to keep you alive and well
and allow you to thrive that's
fascinating that the brain is waiting
for a very specific kind of uh set of
instructions from the world like not
not the specific but a very specific
kind of instruction yes
so you scientists call it expectable
input
the brain needs some input in order to
develop normally
and so we're and we are genetically
you know we as i say in the book we we
have the kind of nature that requires
nurture
we we can't develop normally without
sense
input sensory input from the world and
from the body
and what's really interesting about
humans and
some other animals too but really
seriously in humans is the input that we
need
is not just physical it's also social
we in order for an an infant a human
infant to develop normally
that infant needs eye contact touch
it needs certain types of smells it
needs to be
cuddled it needs right so um
without social input
the brain it's that that infant's brain
will not wire
itself in a neurotypical way and again i
would say
there are lots of um
cultural patterns of caring for an
infant it's not like the infant has to
be cared for in one way
um whatever the social environment
is for an infant that it will will be
reflected in that infant's
internal model so we have lots of
different cultures lots of different
ways of rearing children
and that's an advantage for our species
although we don't always experience it
that way
that is an advantage for our species but
if you
if you just you know feed and water a
baby
without all the extra social doodads
what you get is a profoundly impaired
uh human yeah but
nevertheless you're kind of saying that
the physical reality
has uh has a consistent
thing throughout that keeps feeding
these
set of sensory information that our
brains are constructed
for but yeah the cool thing though is
that if you change the consistency
if you change the statistical
regularities so prediction error
your brain can learn it it's expensive
for your brain to learn it and it takes
a while to
for the brain to get really automated
with it but you know you um
had a wonderful conversation with david
eagleman who just published a book
about this yeah and gave lots and lots
of really very very cool examples
some of which i actually discussed in
how emotions were made but not obviously
to the extent that he did
um in his book which it's a fascinating
book and it's
but it it speaks to the point that
your internal model is always under
construction
and therefore you always
can modify your experience i wonder what
the limits are
like uh if we can if we put it on mars
or if we put in virtual reality
or if we sit at home during a pandemic
and we spend most of our day on twitter
and tick tock
like i wonder what where the breaking
point like the limitations of
the brain's capacity to uh
to properly continue wiring itself
well i think what i would say is that
there are different ways to
specify your question right like one way
to specify it would be the way that
david
um phrases it which is
can we can we create a new sense like
can we create a new sensory modality
how hard would that be what are the
limits in doing that
um and um but another way to
say it is what what happens to a brain
when you
remove some of those statistical
regularities right like what happens to
a brain what happens to an adult brain
when you
remove some of the
statistical patterns that were there and
they're not there anymore
you're talking about in the environment
or in the actual like
you remove eyesight for example or did
you well either way
i mean basically one way to limit
the inputs to your brain are to stay
home and
protect yourself another way is to put
someone
in solitary confinement another way
is to stick them uh in a nursing home
another well not all nursing homes but
you know
but there are some right which really
are
some where peop people are somewhat
impoverished in the interactions the end
this
sensory the variety of sensory
stimulation that they get
another way is that you lose a sense
right but the point is i think that you
know
the human brain really
likes variety to to say it in a
you know like a pro you know sort of
cartesian way
you know variety is a good thing
um for a brain and um
uh
there are risks that you take uh
when you restrict uh what you expose
yourself to
yeah you know there's always talk of
diversity
the brain loves it to the fullest
definition and degree of diversity
yeah i mean i would say the only thing
basically human brains thrive
on diversity the only place where we
seem to have
difficulty with diversity is with each
other
right but we who wants to eat the same
food every day
you never would who wants to wear the
same clothes every day i mean
my husband if you ask him to close his
eyes he won't be able to tell you what
he's wearing
he's just right he'll buy seven shirts
of exactly the same style in different
colors
but they are in different colors right
it's not like how would you then
explain my brain which is
terrified of choice and therefore i wore
the same thing every time
well you must be getting your diversity
well first of all you are a fairly sharp
dresser so
there is that but um so you're getting
some reinforcement progressing the way
that you do
but well your brain must get diversity
in in other words
in other places but i think we you know
the the so there the two most expensive
things your brain can do metabolically
speaking
is um is move your body
um and uh learn something new
so novelty that is diversity
right comes at a cost a metabolic cost
but it's a cost it's an investment that
that gives returns and in general
people vary in how much they like
novelty unexpected things
some people really like it some people
really don't like it and there's
everybody in between
but in general we don't eat the same
thing every day
we don't usually do exactly the same
thing
in exactly the same order in exactly the
same place
every day the only place we have
difficulty
uh with diversity in is
in each other and then we we have
considerable problems there
i would say as a species let me ask uh
i don't know if you're familiar with
donald hoffman's work about
this like questions of reality what are
your
thoughts of the possibility that the
very thing we've been talking about
of the brain wiring itself from birth
to a particular set of inputs is just a
little
slice of reality that there is something
much bigger out there that we humans
with our cognition cognitive
capabilities is just not even perceiving
that the thing we're perceiving is just
the crappy
like windows 95 interface onto a much
bigger richer set of
complex physics that we're not even in
touch with
well without getting too metaphysical
about it i think we know for sure it
doesn't have to be the
you know crappy version of anything but
we definitely have a limited
we have we have a set of senses that are
limited in very physical ways
and we're clearly not perceiving
everything there is to perceive
that's clear i mean it's just it's not
that hard we can't
without special why do we invent
scientific tools it's so that we can
overcome our senses and
and experience things that we couldn't
otherwise whether they are
you know different parts of the uh
visual spectrum the light spectrum
or um things that are too
microscopically
small for us to see or too far away for
us to see
so clearly we're only getting a slice
um and that slice
you know the interesting or
potentially sad thing about humans is
that we
whatever we experience we think there's
a natural reason for experiencing it
and we think it's obvious and natural
and it must be this way
and that all the other stuff isn't
important
and that's clearly not true many of the
things that we think of as natural
are anything but we've cr they're
certainly real but we've created them
they certainly have very real impacts
but we've created those impacts
and we also know that there are many
things outside of our awareness that
have
have tremendous influence on what we
experience
and what we do so there's no question
that that's
true i mean just it's it's um
but the extent is how fantastic really
the question is how fantastical is it
yeah like what you know a lot of people
ask me i'm
i'm not allowed to say this i think i'm
allowed to say this uh i've
eaten shrooms a couple times but i
haven't gone the full
i'm talking to a few researchers and
psychedelics it's an interesting
scientifically place like what is the
portal you're entering when you take
psychedelics or another would ask is
like
dreams whatever so let me tell you what
i think which is based on
nothing like this is based on my life
right so i don't
your intuition it's based on my it's
based on my
i'm guessing now um based on what i do
know
i would say but i think that well think
about what happens
so you're running your brain's running
this internal model right and it's all
outside of your awareness really
you see the you feel the products but
you don't you don't sense the
you have no awareness of the mechanics
of it right
it's going on all the time um
and so one thing that's going on all the
time that you're completely unaware of
is that um when your brain your brain is
basically
asking itself figuratively speaking not
literally right like
how is the scent given the last time i
was in this sensory array with this
stuff going on in my body and i
and that this chain of events which just
occurred
what did i do next what did i feel next
what did i see next
it doesn't come up with one answer it
comes up with a distribution of it
possible answers
and then there has to be some selection
process and so you
have a network in your brain a
subnetwork in your brain a population of
neurons
that helps to choose
it's not i'm not talking about a
homunculus in your brain or anything
silly like that um this is not
the soul it's not the center of yourself
or anything like that but there
is um
a a set of neurons that weighs
the probabilities uh um um and and helps
to select
uh or narrow the field okay and that
that network is working all the time
it's actually called the control network
the executive control network or you can
call it a fronto parietal
because the regions of the brain that
make it up or in the frontal lobe and
the parietal lobe
there are also parts that belong to the
subcortical parts of your brain
it doesn't really matter the point is
tha