June 26, 2023 • 38 mins
Who is doing the choosing when you make a choice? Is there someone in your head but it’s not you? What is a chicken-sexer, and what do they have to do with British plane spotters during WWII? Do we have free will or don’t we? Dive in to discover the ways in which you typically operate with no conscious access to your behaviors.
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Speaker 1 (00:05):
When you make a choice, who exactly is doing the choosing?
Is there someone in your head but it's not you?
What is a chicken sexer? And what do they have
to do with British plane spotters during World War Two?
Do we have free will or don't we? Welcome to
enter cosmos with me, David Eagleman, I'm a neuroscientist at
(00:28):
Stanford and one of my big interests has always been
understanding all the stuff we do that we don't have
access to why we did it, or the stuff we
believe is true, but we don't have access to why
we believe it. So this is going to be a
(00:49):
two parter. In today's episode, I'm going to dive into
all the things that your brain is doing around the
clock that the conscious you has no insight into and
really no acquaintance with all this activity that lives within
what we call the unconscious brain. You're only conscious of
(01:09):
a tiny bit of what's happening under the hood. So
today we're going to see how all this unconscious activity
drives so much more of your life than you would
have imagined. And then in the next episode, I'll talk
about what all this means for our legal system. If
your behavior and your choices are driven by parts of
(01:31):
your brain that you have little or no control over,
what does that mean if you commit a crime, can
you help that you did it? Did you have a
choice or does your brain get formed by your genetics
and your childhood experience, neither of which you had any
choice over? So what does that all mean for the
notion of fault and blame worthiness in our legal system?
(01:56):
What would that mean for our courts? Because you can't
just let everyone off the hook, even if they didn't
have a choice and who they are right. So next
week we'll dive into what happens at the intersection of
neuroscience and the legal system and how we can build
a system moving forward that gets bad actors off the
street and is compatible with insights of modern neuroscience. So
(02:19):
let's start at the beginning. Ours is an incredible story.
As far as anyone can tell. We are the only
species on the planet that has grown so complex that
we have thrown ourselves headlong into this game of reverse
engineering ourselves. Imagine that you plugged some peripheral devices into
(02:40):
your laptop and it began to control those and removed
its own cover and pointed its webcam at its own
circuitry and tried to figure out how it runs. That's us,
that's our species. And what we have discovered by peering
into the skull ranks some among our most significant intellectual developments.
(03:03):
What we found is that all the facets of our behavior,
our thoughts, our experiences, these are inseparably yoked to this vast,
wet chemical electrical network called the nervous system. And this
machinery is totally alien to us, and yet somehow it
(03:25):
is us. When we look at the brain, this is
the most complex device we have ever found in our universe.
The human brain is made up of eighty six billion
specialized cells called neurons, and each neuron is as complicated
(03:46):
as the city of New York. Every neuron contains the
entire human genome, and it's trafficking millions of proteins around
inside it. And every neuron is connected to about ten
thousand of its neighbors. So that means you have something
like five hundred trillion connections in your brain. So that
means if you took a cubic centimeter of your brain
(04:09):
and you examined that there are as many connections in
there as there are stars in the Milky Way galaxy.
It's totally impossible for any of us to understand a
system of this complexity. But one thing is clear. This
three pounds of wet biological stuff is you. All your thoughts,
(04:30):
your hopes, your fears, the agony and the ecstasy. It's
all happening right inside here in your brain, in the
darkness of your skull. So, in other words, it's not
that you have a brain, it's that you are your brain.
So how do we know this, Well, imagine you were
(04:52):
to get in a car accident and you hurt the
tip of your pinky. You'd be sad about that, but
you wouldn't be any different as a person. But if
you were to damage an equivalently sized little chunk of
brain tissue, that can change you entirely. That can change
your decision making or your appetite for risk, or your
(05:13):
ability to see colors or name animals, or understand music,
or read signals from your body, or to understand the
concept of a mirror, or one hundred other things that
we see every day in the clinics when people get
brain damage due to strokes or tumors or traumatic brain injury.
(05:33):
Now here's the surprise. Almost all of this machinery of
you runs under the hood, meaning you don't even have
access to it or have any acquaintance with it. So
think about moving your arm to get your coffee mug
to your mouth. That feels very simple, but it's actually
underpinned by a lightning storm of brain activity. Literally, hundreds
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of millions of neurons are popping off the chattering with
these electrical spikes between tens or hundreds of times per
second to allow you to grip the cup see the
cup arranger. Grip on the handle, lift it with the
right strength, bring it to your mouth, position it against
your lower lip tilted, take a sip. Okay. The remarkable
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thing is you don't have any awareness of all these
microscopic neurons and their massive dialogue that they're chattering away in.
And by massive, I mean every neuron in your head
is shooting off these little electrical spikes tens or hundreds
of times per second every second of your life. And
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multiply that times these eighty six billion neurons. If you
represented each spike by a single photon of light, the
action inside your skull at any moment would be blinding.
But the thing I want to zoom into today is
that you don't have any awareness of this, any insight
or consciousness of all the action going on. The only
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thing you know is whether you spilled the coffee on
yourself or not. That's it. All the action is happening
at the level of billions of biological cells, and you
don't even know how you do it. Now, it's not
just your cup of coffee. It's everything in your life.
It's how you drive a car, it's how you recognize
a friend's face, it's how you get a joke, it's
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how you fall in love. These are all underpinned by
massive storms of electrochemical activity inside the darkness of your skull.
So the conscious you is really the smallest part of
what your brain is up to. Here's an example that
got me thinking about this. When I was young. There
was an old experiment at the University of Chicago. And
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in this experiment, men were asked to rate how attractive
they found photographs of different women's faces. So the photographs
were eight by ten photos and they would flip through
them and they would rank each women from one to ten. Now,
unbeknown to the men, in half the photographs, the eyes
were dilated, and in the other half of the photographs
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the eyes were normal. So the result turned out to
me that the men were consistently more attracted to the
women with dilated eyes. But the important point is that
the men had no insight into their decision making. None
of them said, oh, I noticed that her pupils were
two millimeters larger than her pupils, And presumably none of
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the men knew that dilated eyes is a biological sign
of reciprocal attraction. But their brains knew it, and here
they were making the right sorts of decisions, as carved
by millions of years of natural selection, without having any
idea why they were making those decisions. They simply felt
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more drawn towards some women than others for reasons they
couldn't put finger on. So who was doing the choosing.
It wasn't really like the men were choosing, but instead
it was a choice of successful neural programs that had
been burned deep into the circuitry over the course of
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hundreds of thousands of generations. Brains are in the business
of gathering information and steering behavior appropriately, and it doesn't
matter whether consciousness is involved in the decision making, and
most of the time it's not. This is true whether
we're talking about dilated eyes, or the sting of jealousy,
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or the pull of attraction, or your love of sugary
cookies or the great idea that popped into your head
last week. For all of these, consciousness is the smallest
player in the operations of your brain. Your brain runs
mostly on autopilot, and your conscious mind has very little
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access to the giant and mista furious factory that runs
below it. And when you start looking around, you see
evidence of this all around you. So think of when
your foot gets halfway to the break of your car
before you consciously realize that a truck is backing out
of a driveway on the road ahead of you, or
when you notice your name spoken in a conversation across
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the room that you thought you weren't listening to. You
see this when you're in a conversation and you don't
know the words that are going to spill out of
your mouth, You the conscious you just sits in the
back seat and waits to see what comes pouring out. Now,
the brain is massively complex, but that doesn't mean that
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it's incomprehensible. Our neural circuits were carved by natural selection
to solve problems that our ancestors faced during our species
evolutionary history. So your brain has been molded by evolutionary pressures,
just like your spleen and your eyes have, and so
has your consciousness. Consciousness developed because it was advantageous, but
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only advantageous in limited amounts. So why do we have
consciousness at all? Well, think of this as an analogy.
Look at all the activity that's happening in the nation
at any moment. You've got factories going and telecommunication lines
and businesses shipping product and people eating, and police chasing
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criminals and schools running and lovers rendezvousing, and everyone's doing
their thing, teachers and athletes and doctors. There's a ton
of action going on in the nation. Now, you want
to know what's happening in the nation, but you can't
possibly take in all this information at once. It's too
much to be useful even if you could take it in.
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So what you want is a summary. So you go
to a news website and you won't be surprised that
none of the details are listed there, because really you
just want to know the bottom line. You want to
know that Congress just signed a law that affects you,
But you don't have interest in the detailed history of
the bill, and you don't want to know all the
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details of the food supply of the nation. You only
want to be alerted if there's something that affects you.
You don't care how the garbage is produced and packed away.
You only care if it's going to end up in
your backyard. That's what you get from reading the news headlines.
Your conscious mind gives you the headlines. Your brain is
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buzzing with activity around the clock, and just like the nation,
everything is happening locally. You've got groups of neurons that
are making decisions and sending out messages to other groups.
And out of these local interactions emerge larger coalitions. And
by the time you read a mental headline, all the
important action has already transpired, all the deals are done.
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You have shockingly little access to what happened behind the
scenes to lead you up to this moment. Entire political
movements have gained ground up support and become unstoppable before
you ever catch wind of them as a feeling or
an intuition or a thought. That strikes you. You're the
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last one to hear the information. But strangely, you're an
odd kind of newsreader because you read the headline and
you take credit for the idea as though you thought
of it first. Just think about when you have an
idea and you say, oh, I just thought of something.
It wasn't exactly you that thought of it. Your brain's
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been working on that behind the scenes for hours or
days or weeks, consolidating information, evaluating options, and eventually it
serves something up to your conscious mind and you say, oh,
I'm a genius, but it wasn't really you. Right, you're
taking credit without considering the vast hidden machinery behind the scenes.
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So the conscious you, which is the part that flickers
to life when you wake up in the morning, that's
the smallest bit of what's going on in your brain.
It's a broom closet in the mansion of the brain.
Most of what you think and do and believe is
generated by functions of your brain to which you have
no access. So the conscious mind is like a stowaway
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on a transatlantic steamship that's taking credit for the whole
journey without acknowledging all the massive engineering that's underfoot, and
it kind of has to be that way because really
the conscious mind is acting like the CEO of an
enormous organization. So think if you're the CEO of some
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huge international company, you can't possibly get involved with all
the little tasks of knowing what software version is on employees' computers,
or where the food for the cafeteria is coming from,
or where the truck tires are being ordered from. The
organization is just way too big. So your job as
the CEO is to kick your feet up on the
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desk and wait for the phond erring if there's a problem.
And this is essentially what the conscious mind is doing.
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So who exactly deserves the credit for the great idea
that you have? This is a tough one that people
have been wrestling with for ages. I was recently reading
about the mathematician James Clerk Maxwell, who in eighteen sixty
two developed a set of Sweet equations to unify electricity
with magnetism. But on his deathbed he said that quote
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something within him unquote discovered the famous equations, not him.
He had admitted that he had no idea how ideas
actually came to him. They simply came to him. The
author William Blake wrote the long poem Milton, and later
he said, quote, I have written this poem from immediate dictation,
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twelve or sometimes twenty lines at a time, without premeditation,
and even against my will unquote. Or the novelist Kurtis
said that he had written one of his novellas with
practically no conscious input, as though he were holding a
pen that moved on its own. Or think about the
British poet Samuel Taylor Coleridge. He started to use opium
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in seventeen ninety six, and originally it was for relief
from toothaches, but after a while he was addicted and
he wrote his famous poem Kubla Khan on an opium high.
Now we give credit for that poem to Coleridge because
it came from his brain and no one else's right,
But he couldn't get hold of those words while so, so,
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who exactly does credit for the poem belong to? As
Carl Jung said, in each of us there is another
whom we do not know, Or as Pink Floyd put it,
there's someone in my head, but it's not me. Almost
everything in your mental life is not under your conscious control.
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And the truth is it's better that way. Consciousness can
take all the credit it wants, but it's best left
at the sidelines for most of the decision making that
cranks along in your brain. When your conscious mind messes
with details that it doesn't understand, the whole operation runs
less effectively. So if you play the piano, you know
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that if you start to think about where your fingers
are going, you're dead. You can't do it anymore. Or
here's something to try. I want you to try this.
Take two dry erase markers and go stand in front
of the dry erase port. And what I want you
to do is write your signature with your right hand
at the same time that you're writing it backwards with
your left hand. So you're writing your signature and its
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mirror reverse at the same time. So go ahead, try
this for a moment if you are near a dry
erase board, and you'll quickly find that there's only one
way you can do it, and that is if you
don't think about it at all. The moment you start
thinking about what a backwards letter looks like, the whole
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thing fails. You stumble, and you stutter along and you
just can't do it. But you actually can't do this
if you simply don't think about it, if you just
zen out and let your hands do the work. So
you can only do it if you exclude conscious thought.
Here's another example. Pretend you're driving, and what I want
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you to do is actually put your hands up on
an imaginary steering wheel in front of you. So put
your hands there, and if you're in a car while
listening to this podcast, don't do this, okay. So imagine
with your hands on the imaginary steering wheel that you
are in the center lane going thirty miles an hour,
and I want you to make a lane change into
your right lane. So go ahead and turn the wheel
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in the way that you would to make a lane change. Now,
if you're like essentially everybody who I've ever tried this with,
what you do is you turn your wheel to the
right and then back to center. Is that what you did, Okay?
So that turns your car to the right, and now
you bump over the sidewalk and you crash into the buildings.
The way you make a lane change is by turning
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the steering wheel to the right, then back through the center,
and just as far to the left and then you're
back to the center again. So if you're in a car,
pay attention to how you're doing this, and you'll see
that's how you make a lane change, and you do
it every day and you have no idea how you're
doing it. Why. It's because your unconscious brain is taking
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care of all the details for you and you don't
even have access to what you're doing. So you can
do lots of things well with no consciousness involved. When
I was younger, I used to play baseball and my
coach would always say to us, I want you guys
to think out there. And I would say to him, actually,
you don't want us to think out there. You want
us to train a sufficient number of hours so that
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we automatize all these behaviors and then we go out
there and perform. But the last thing you want us
doing out there is thinking, because we would never connect
the bat with the ball or catch the pop fly.
But he never believed me, so I had to go
become a neuroscientist and write books to convince him that
consciousness typically doesn't even get invited to the party. And
by the way, when consciousness does get any insight, it's
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always the last one to hear the information. So think
about hitting a baseball. In twenty ten, the Guinness Book
of World Records clocked a fastball from the Cincinnati pitcher
or all this Chapman, at one hundred and five point
eight miles per hour. So if you work the numbers,
what you see is that Chapman's pitch left the mound
and cross the home plate in four tenths of a second,
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four hundred milliseconds. What that means is there's just enough
time for light signals from the baseball to reach the
batter's eye work through the circuitry of the retina. Activate
these successions of cells along the loopy super highways of
the visual system at the back of the head, cross
the vast territories to the motor areas, and modify the
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contraction of the muscles swinging the bat. And amazingly, this
entire sequence is possible in less than four tenths of
a second. Otherwise no one would ever hit a fastball.
But the surprising part is that conscious awareness takes longer
than that, at least half a second, so the ball
travels too rapidly for batters to be consciously aware of it.
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And when I was playing baseball, my experience of hitting
the ball was always this. I would stand there ready
to swing, and then I would become consciously aware that
I had hit the ball and it was flying away
from me, and then I would say to myself, you
hit the ball, Now drop the bat and run. But
the actual moment of hitting the ball with the bat
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was always moving way ahead of my slow consciousness, which
was the last one on the ladder to get any
of the news of what was transpiring. And all. This
is the case because you don't need to be consciously
aware to perform sophisticated motor acts. You can notice this
when you begin to duck from a snapping tree branch
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before you are aware that is coming towards you, or
you're already jumping up by the time you realize that
your cell phone is ringing across the room. So these
examples about writing your signature backward, or changing lanes, or
hitting a baseball, these are a few among thousands. You
are not consciously aware of the vast majority of your
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brain's ongoing activities, and nor would you want to be.
It would interfere with the brain's well oiled processes. The
best way to mess up your piano piece is to
concentrate on your fingers. The best way to get out
of breath is to think about your breathing. The best
way to miss your golf ball is to think too
much about your swing. And by the way, this wisdom
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is apparent even to children. We find it immortalized in
poems like the Puzzled Centipede, which goes like this. A
centipede was happy quite until a frog in fun said,
pray tell which leg comes? After which this raised her
mind to such a pitch she lay distracted in the ditch,
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not knowing how to run. So this ability to remember
how to do motor acts like changing lanes is called
procedural memory, and it's a type of implicit memory. Implicit
means that your brain holds the knowledge of something that
your conscious mind can't access, like riding a bike, or
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tying your shoes, or typing on a keyboard, or steering
your car into a parking space while you're talking on
your cell phone. These are all examples of implicit memory.
You can execute these actions easily enough without having any
idea of exactly how you do it. You would be
totally unable to describe the perfectly timed choreography with which
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your muscles contract and relax as you do these things,
or as you navigate around other people in a cafeteria
while you're holding a tray. But you don't have any
trouble doing any of these things. This is the gap
between what your unconscious brain can do and what you
can access consciously. To the extent that consciousness is useful,
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it's useful in small quantities and for very particular kinds
of tasks. It's easy enough to understand why you wouldn't
want to be consciously aware of the intricacies of your
muscle movement, but this can be a little less intuitive
when applied to your perceptions and thoughts and beliefs, which
are also the final products of the activity of billions
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of nerve cells. For a good example of this, can
consider chicken sexers. So what is a chicken sexer? Well,
when little chicken hatchlings are born, large commercial hatcheries divide
them up into males and females, and this practice of
figuring out which is which, of distinguishing the two genders,
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this is known as chicken sexing. Now the hatcheries divide
them up because the two genders get different feeding programs.
The females who will eventually lay eggs are highly valued,
but sadly, most of the males are disposed of because
they don't produce eggs, and only a few males are
kept in fatten for meat. So anyway, the job of
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the chicken sexor is to pick up each hatchling and
quickly determine its sex in order to choose the correct
bin to put it in. The problem is that this
task is famously difficult because female and male chicks look
exactly alike, well almost exactly. So the Japanese invented a
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method of sexing chicks known as vent sexing, by which
expert chicken sexers could rapidly figure out the sex of
one day old hatchlings. So, beginning in the nineteen thirties,
poultry breeders from around the world traveled to the zen
Nippon Chick Sexing School in Japan to learn the technique.
The mystery was that no one could explain exactly how
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it was done. It was somehow based on very subtle
visual cues, but the professional chick sexors could not report
what those cues were. Instead, they would look at the
chicks rear end where the vent is and simply seem
to know the correct bin to put it in. And
this is how the professionals taught the students. The master
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would stand over the apprentice and watch the student would
pick up a chick, examine its rear, and put it
in one bin or the other, and the master would
give feedback yes or no. And after weeks on end
of this activity, the student's brain was trained up to
masterful levels that were totally unconscious. They could tell the
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sects of the chicken, but they had no idea how
they were doing it. Meanwhile, a similar story was unfolding
on the other side of the world during World War Two.
Under a constant threat of bombings, the British had to
figure out how to distinguish incoming aircraft quickly and accurately.
Which aircraft were British planes coming home and which were
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German planes coming to bomb. So, as it turns out,
there were several airplane enthusiasts who proved to be excellent spotters,
so the military eagerly employed their services. These spotters were
so valuable that the government quickly tried to enlist more spotters,
but they turned out to be very rare and difficult
to find. So what did the government do. They tried
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to get the spotters to sit down and train other spotters,
but that turned out to be a total fail because
the spotters tried to explain their strategies but failed. No
one got it, not even the spotters themselves. Just like
the chicken sextors, the spotters had no idea how they
did what they did. They simply saw the right answer.
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But with a little ingenuity, the British finally figured out
how to successfully train new spotters, and it was just
by trial and error feedback. So the novice would hazard
a guess and say I think that's a British plane
or I think that's a German plane, and the expert
would say yes or no, and eventually the novices became
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like their mentors, vessels of this mysterious, ineffable expertise. So
there can be a really large gap between knowledge that
your brain has and your conscious awareness. So when we
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examine skills that aren't available to introspection, like making a
lane change, or hitting the baseball or chicken sexing, the
first surprise is that your brain's unconscious memory for something
your implicit memory is totally separable from things that you
can talk about consciously or your explicit memory. You can
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damage one without hurting the other. So, for example, sometimes
a person will get brain damage and get what's called
antaro grade amnesia, which means they can't consciously recall new
experiences in their lives. If you spend an afternoon trying
to teach a person like this the video game Tetris,
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they'll tell you the next day that they have no
recollection of the experience. They've never seen this deo game before,
and most likely they don't have any idea who you
are either. But if you look at their performance on
the game the next day, you'll find that they have
improved exactly as much as a person without amnesia. In
other words, their brains have learned the game implicitly. The
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knowledge is there, it's just that it's not accessible to
their consciousness. By the way, it's an interesting side note.
If you wake up an amnestic patient during the night
after they've played Tetris, they'll report to you that they
were dreaming of colorful falling blocks, but they have no
idea why. And of course it's not just checking sexors
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and plane spotters and people with amnesia who enjoy unconscious learning. Essentially,
everything about your interaction with the world rests on this process.
You probably would have a difficult time putting into words
the characteristics of your father's walk, or the shape of
his nose, or the way that he laughs. When you
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see someone who walks or looks or laughs like him,
you know it immediately. Now, I want to return to
this point that I mentioned at the beginning, which is
that you are your brain and this is why things
like brain damage can change you. But you don't need
brain damage to prove this to yourself. Just look at
the ways that you change when your biology changes. So
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consider alcohol. You pour these invisibly small ethanol molecules into
your system, and that alters your perception and your behavior.
Your social inhibitions are lower, you feel freer, you think
your funnier at parties, you do more adventurous things. It's
just a molecule of a particular shape that interacts with
the membranes of your neurons. But it very slightly changes
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the way that information flows through these giant networks, and
so who you are becomes slightly different. And drugs of
all sorts influence our behavior this is obvious with narcotics.
They slightly tweak the behavior of the network. And now
you're talking to silver leprechauns. And I'll give you another
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interesting example of the influence of molecules. Take the professional
wrestler Chris Benoit, who was this giant muscley guy who
had a world heavyweight championship. And he went home one
night in two thousand and seven and he murdered his
wife and his son and he hung himself from one
of the pulleys of his weight machines. Now, at the autopsy,
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they figured out he was on massive doses of the
steroid testosterone and other anabolic steroids, and these can cause
paranoia and violent outbursts, and it's known as roid rage.
You change the exact balance of chemicals under the hood,
and you change your decision making you change who you are.
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And by the way, these kinds of changes and who
you are, these applied to prescription medications as well. Some
years ago, physicians began noticing that some of their patients
who had Parkinson's disease were becoming compulsive gamblers, and they
were blowing their families money in Las Vegas or Atlantic
City or online poker. Now, Parkinson's disease involves a decrease
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in a neurotransmitter called dopamine, and so the medications to
help that they crank up dopamine levels and that makes
the tremors and the rigidity go away. But dopamine also
plays a second role in your brain, not just involving
how your muscles work, but also in your reward systems.
So it turns out that by ratcheting up the level
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of dopamine it was changing the decision making of the patients.
It gave them a much bigger appetite for risk taking,
and one of the ways this expresses itself is with gambling.
So nowadays these Parkinson's medications come with a warning on
the label that if you notice an increase in gambling
or other risk taking behavior, then the dosage should be
(33:56):
turned down. So what's clear is that the soul I'm
total of your neurochemistry, whether from alcohol or drugs, or abuse,
or steroids or clinical medications, whatever, these modify your behavior.
So nowadays, what this all means is that when we
talk about morality and decision making, what we're really talking
(34:18):
about is the neural basis of this and this leads
us to the very deep question about freewill. Is the
mind separate from the brain or are they the same thing?
And because of all the cases we have of brain
damage and narcotics and disease states, and how people's behavior
changes when their brain changes, it's a very reasonable hypothesis
(34:41):
that you do not have free will. You are your brain.
And although it's a mind bogglingly complex system, it's nonetheless
a machine, a giant machine whose complexity we could never capture,
but a machine nonetheless. As far as we can tell,
every neuron that we measure is driven by the activity
of other neurons, and those are driven by the activity
(35:03):
of other neurons. So it's not even clear where that
extra bit of free will would even live, what would
make the whole machine not a machine. So try this.
Whatever your sexual orientation is, go ahead and switch it.
So if you're straight, become gay, and if you're gay,
go become straight. Go ahead, I'll wait, Okay, good luck, right,
(35:24):
Because free will isn't really what you might into it.
It's not like you just make a decision about something
consciously and then that's where things go. And this is
the same with addictions and cravings and temptations. You can't
just say, look, I'm the kind of person who doesn't
like cookies or sex or food or whatever, and then
that's how things go. There's a lot running under the
(35:44):
hood that you have no access to and no acquaintance with. Now.
I'm going to cover the free will question in much
more depth in future episodes, but for now, I just
want to say it's a bit of a difficult one
to answer. Do we have absolutely no free will? Do
we have a little bit of it? I think it's
fair to say that most neuroscientists land on the position
that we probably have none. Because every neuron in the
(36:06):
brain is driven by other neurons, then it's not clear
where you get the extra bit. I just want a
flag that, given the available data, I think it's probably
too early for us to conclude on this point with
absolute certainty, because our science is still quite young. But
what is absolutely clear is that if we have any
free will at all, it is just a bit player
(36:27):
in the system. The unconscious brain is the one in charge,
and the conscious you is not driving the boat. So
even if there is just a little bit of free will,
just about everything you think and do and act and
believe is generated by parts of your brain that are
doing their own thing. Okay, so let's wrap up. What
(36:48):
we've done in this episode is set up some foundational
issues about how little we have access to what's running
in our brains, all the activity that determines who we
are and how we act what we believe. So join
me next week for part two, where we'll ask how
all this could or should affect the legal system. If
(37:09):
we don't have free will or very little of it,
what does that mean for the notion of culpability? In
what sense are we responsible for our actions when there's
so much running under the hood and so little conscious choice.
We can't not take bad actors off the street, but
how do we reconcile these two fields of neuroscience and
(37:31):
legal theory. To find out more and to share your thoughts,
head to Eagleman dot com, slash Podcasts, and you can
also watch full episodes of Inner Cosmos on YouTube at
inner cosmospod subscribe to see new episodes every week until then.
(37:53):
This is David Eagleman signing off from the Inner Cosmos
When you make a choice, who exactly is doing the choosing?
Is there someone in your head but it's not you?
What is a chicken sexer? And what do they have
to do with British plane spotters during World War Two?
Do we have free will or don't we? Welcome to
enter cosmos with me, David Eagleman, I'm a neuroscientist at
(00:28):
Stanford and one of my big interests has always been
understanding all the stuff we do that we don't have
access to why we did it, or the stuff we
believe is true, but we don't have access to why
we believe it. So this is going to be a
(00:49):
two parter. In today's episode, I'm going to dive into
all the things that your brain is doing around the
clock that the conscious you has no insight into and
really no acquaintance with all this activity that lives within
what we call the unconscious brain. You're only conscious of
(01:09):
a tiny bit of what's happening under the hood. So
today we're going to see how all this unconscious activity
drives so much more of your life than you would
have imagined. And then in the next episode, I'll talk
about what all this means for our legal system. If
your behavior and your choices are driven by parts of
(01:31):
your brain that you have little or no control over,
what does that mean if you commit a crime, can
you help that you did it? Did you have a
choice or does your brain get formed by your genetics
and your childhood experience, neither of which you had any
choice over? So what does that all mean for the
notion of fault and blame worthiness in our legal system?
(01:56):
What would that mean for our courts? Because you can't
just let everyone off the hook, even if they didn't
have a choice and who they are right. So next
week we'll dive into what happens at the intersection of
neuroscience and the legal system and how we can build
a system moving forward that gets bad actors off the
street and is compatible with insights of modern neuroscience. So
(02:19):
let's start at the beginning. Ours is an incredible story.
As far as anyone can tell. We are the only
species on the planet that has grown so complex that
we have thrown ourselves headlong into this game of reverse
engineering ourselves. Imagine that you plugged some peripheral devices into
(02:40):
your laptop and it began to control those and removed
its own cover and pointed its webcam at its own
circuitry and tried to figure out how it runs. That's us,
that's our species. And what we have discovered by peering
into the skull ranks some among our most significant intellectual developments.
(03:03):
What we found is that all the facets of our behavior,
our thoughts, our experiences, these are inseparably yoked to this vast,
wet chemical electrical network called the nervous system. And this
machinery is totally alien to us, and yet somehow it
(03:25):
is us. When we look at the brain, this is
the most complex device we have ever found in our universe.
The human brain is made up of eighty six billion
specialized cells called neurons, and each neuron is as complicated
(03:46):
as the city of New York. Every neuron contains the
entire human genome, and it's trafficking millions of proteins around
inside it. And every neuron is connected to about ten
thousand of its neighbors. So that means you have something
like five hundred trillion connections in your brain. So that
means if you took a cubic centimeter of your brain
(04:09):
and you examined that there are as many connections in
there as there are stars in the Milky Way galaxy.
It's totally impossible for any of us to understand a
system of this complexity. But one thing is clear. This
three pounds of wet biological stuff is you. All your thoughts,
(04:30):
your hopes, your fears, the agony and the ecstasy. It's
all happening right inside here in your brain, in the
darkness of your skull. So, in other words, it's not
that you have a brain, it's that you are your brain.
So how do we know this, Well, imagine you were
(04:52):
to get in a car accident and you hurt the
tip of your pinky. You'd be sad about that, but
you wouldn't be any different as a person. But if
you were to damage an equivalently sized little chunk of
brain tissue, that can change you entirely. That can change
your decision making or your appetite for risk, or your
(05:13):
ability to see colors or name animals, or understand music,
or read signals from your body, or to understand the
concept of a mirror, or one hundred other things that
we see every day in the clinics when people get
brain damage due to strokes or tumors or traumatic brain injury.
(05:33):
Now here's the surprise. Almost all of this machinery of
you runs under the hood, meaning you don't even have
access to it or have any acquaintance with it. So
think about moving your arm to get your coffee mug
to your mouth. That feels very simple, but it's actually
underpinned by a lightning storm of brain activity. Literally, hundreds
(05:56):
of millions of neurons are popping off the chattering with
these electrical spikes between tens or hundreds of times per
second to allow you to grip the cup see the
cup arranger. Grip on the handle, lift it with the
right strength, bring it to your mouth, position it against
your lower lip tilted, take a sip. Okay. The remarkable
(06:21):
thing is you don't have any awareness of all these
microscopic neurons and their massive dialogue that they're chattering away in.
And by massive, I mean every neuron in your head
is shooting off these little electrical spikes tens or hundreds
of times per second every second of your life. And
(06:41):
multiply that times these eighty six billion neurons. If you
represented each spike by a single photon of light, the
action inside your skull at any moment would be blinding.
But the thing I want to zoom into today is
that you don't have any awareness of this, any insight
or consciousness of all the action going on. The only
(07:05):
thing you know is whether you spilled the coffee on
yourself or not. That's it. All the action is happening
at the level of billions of biological cells, and you
don't even know how you do it. Now, it's not
just your cup of coffee. It's everything in your life.
It's how you drive a car, it's how you recognize
a friend's face, it's how you get a joke, it's
(07:28):
how you fall in love. These are all underpinned by
massive storms of electrochemical activity inside the darkness of your skull.
So the conscious you is really the smallest part of
what your brain is up to. Here's an example that
got me thinking about this. When I was young. There
was an old experiment at the University of Chicago. And
(07:51):
in this experiment, men were asked to rate how attractive
they found photographs of different women's faces. So the photographs
were eight by ten photos and they would flip through
them and they would rank each women from one to ten. Now,
unbeknown to the men, in half the photographs, the eyes
were dilated, and in the other half of the photographs
(08:14):
the eyes were normal. So the result turned out to
me that the men were consistently more attracted to the
women with dilated eyes. But the important point is that
the men had no insight into their decision making. None
of them said, oh, I noticed that her pupils were
two millimeters larger than her pupils, And presumably none of
(08:35):
the men knew that dilated eyes is a biological sign
of reciprocal attraction. But their brains knew it, and here
they were making the right sorts of decisions, as carved
by millions of years of natural selection, without having any
idea why they were making those decisions. They simply felt
(08:55):
more drawn towards some women than others for reasons they
couldn't put finger on. So who was doing the choosing.
It wasn't really like the men were choosing, but instead
it was a choice of successful neural programs that had
been burned deep into the circuitry over the course of
(09:15):
hundreds of thousands of generations. Brains are in the business
of gathering information and steering behavior appropriately, and it doesn't
matter whether consciousness is involved in the decision making, and
most of the time it's not. This is true whether
we're talking about dilated eyes, or the sting of jealousy,
(09:36):
or the pull of attraction, or your love of sugary
cookies or the great idea that popped into your head
last week. For all of these, consciousness is the smallest
player in the operations of your brain. Your brain runs
mostly on autopilot, and your conscious mind has very little
(09:57):
access to the giant and mista furious factory that runs
below it. And when you start looking around, you see
evidence of this all around you. So think of when
your foot gets halfway to the break of your car
before you consciously realize that a truck is backing out
of a driveway on the road ahead of you, or
when you notice your name spoken in a conversation across
(10:20):
the room that you thought you weren't listening to. You
see this when you're in a conversation and you don't
know the words that are going to spill out of
your mouth, You the conscious you just sits in the
back seat and waits to see what comes pouring out. Now,
the brain is massively complex, but that doesn't mean that
(10:40):
it's incomprehensible. Our neural circuits were carved by natural selection
to solve problems that our ancestors faced during our species
evolutionary history. So your brain has been molded by evolutionary pressures,
just like your spleen and your eyes have, and so
has your consciousness. Consciousness developed because it was advantageous, but
(11:06):
only advantageous in limited amounts. So why do we have
consciousness at all? Well, think of this as an analogy.
Look at all the activity that's happening in the nation
at any moment. You've got factories going and telecommunication lines
and businesses shipping product and people eating, and police chasing
(11:27):
criminals and schools running and lovers rendezvousing, and everyone's doing
their thing, teachers and athletes and doctors. There's a ton
of action going on in the nation. Now, you want
to know what's happening in the nation, but you can't
possibly take in all this information at once. It's too
much to be useful even if you could take it in.
(11:48):
So what you want is a summary. So you go
to a news website and you won't be surprised that
none of the details are listed there, because really you
just want to know the bottom line. You want to
know that Congress just signed a law that affects you,
But you don't have interest in the detailed history of
the bill, and you don't want to know all the
(12:09):
details of the food supply of the nation. You only
want to be alerted if there's something that affects you.
You don't care how the garbage is produced and packed away.
You only care if it's going to end up in
your backyard. That's what you get from reading the news headlines.
Your conscious mind gives you the headlines. Your brain is
(12:31):
buzzing with activity around the clock, and just like the nation,
everything is happening locally. You've got groups of neurons that
are making decisions and sending out messages to other groups.
And out of these local interactions emerge larger coalitions. And
by the time you read a mental headline, all the
important action has already transpired, all the deals are done.
(12:54):
You have shockingly little access to what happened behind the
scenes to lead you up to this moment. Entire political
movements have gained ground up support and become unstoppable before
you ever catch wind of them as a feeling or
an intuition or a thought. That strikes you. You're the
(13:14):
last one to hear the information. But strangely, you're an
odd kind of newsreader because you read the headline and
you take credit for the idea as though you thought
of it first. Just think about when you have an
idea and you say, oh, I just thought of something.
It wasn't exactly you that thought of it. Your brain's
(13:35):
been working on that behind the scenes for hours or
days or weeks, consolidating information, evaluating options, and eventually it
serves something up to your conscious mind and you say, oh,
I'm a genius, but it wasn't really you. Right, you're
taking credit without considering the vast hidden machinery behind the scenes.
(14:00):
So the conscious you, which is the part that flickers
to life when you wake up in the morning, that's
the smallest bit of what's going on in your brain.
It's a broom closet in the mansion of the brain.
Most of what you think and do and believe is
generated by functions of your brain to which you have
no access. So the conscious mind is like a stowaway
(14:25):
on a transatlantic steamship that's taking credit for the whole
journey without acknowledging all the massive engineering that's underfoot, and
it kind of has to be that way because really
the conscious mind is acting like the CEO of an
enormous organization. So think if you're the CEO of some
(14:45):
huge international company, you can't possibly get involved with all
the little tasks of knowing what software version is on employees' computers,
or where the food for the cafeteria is coming from,
or where the truck tires are being ordered from. The
organization is just way too big. So your job as
the CEO is to kick your feet up on the
(15:07):
desk and wait for the phond erring if there's a problem.
And this is essentially what the conscious mind is doing.
(15:29):
So who exactly deserves the credit for the great idea
that you have? This is a tough one that people
have been wrestling with for ages. I was recently reading
about the mathematician James Clerk Maxwell, who in eighteen sixty
two developed a set of Sweet equations to unify electricity
with magnetism. But on his deathbed he said that quote
(15:53):
something within him unquote discovered the famous equations, not him.
He had admitted that he had no idea how ideas
actually came to him. They simply came to him. The
author William Blake wrote the long poem Milton, and later
he said, quote, I have written this poem from immediate dictation,
(16:16):
twelve or sometimes twenty lines at a time, without premeditation,
and even against my will unquote. Or the novelist Kurtis
said that he had written one of his novellas with
practically no conscious input, as though he were holding a
pen that moved on its own. Or think about the
British poet Samuel Taylor Coleridge. He started to use opium
(16:39):
in seventeen ninety six, and originally it was for relief
from toothaches, but after a while he was addicted and
he wrote his famous poem Kubla Khan on an opium high.
Now we give credit for that poem to Coleridge because
it came from his brain and no one else's right,
But he couldn't get hold of those words while so, so,
(17:01):
who exactly does credit for the poem belong to? As
Carl Jung said, in each of us there is another
whom we do not know, Or as Pink Floyd put it,
there's someone in my head, but it's not me. Almost
everything in your mental life is not under your conscious control.
(17:21):
And the truth is it's better that way. Consciousness can
take all the credit it wants, but it's best left
at the sidelines for most of the decision making that
cranks along in your brain. When your conscious mind messes
with details that it doesn't understand, the whole operation runs
less effectively. So if you play the piano, you know
(17:42):
that if you start to think about where your fingers
are going, you're dead. You can't do it anymore. Or
here's something to try. I want you to try this.
Take two dry erase markers and go stand in front
of the dry erase port. And what I want you
to do is write your signature with your right hand
at the same time that you're writing it backwards with
your left hand. So you're writing your signature and its
(18:05):
mirror reverse at the same time. So go ahead, try
this for a moment if you are near a dry
erase board, and you'll quickly find that there's only one
way you can do it, and that is if you
don't think about it at all. The moment you start
thinking about what a backwards letter looks like, the whole
(18:25):
thing fails. You stumble, and you stutter along and you
just can't do it. But you actually can't do this
if you simply don't think about it, if you just
zen out and let your hands do the work. So
you can only do it if you exclude conscious thought.
Here's another example. Pretend you're driving, and what I want
(18:46):
you to do is actually put your hands up on
an imaginary steering wheel in front of you. So put
your hands there, and if you're in a car while
listening to this podcast, don't do this, okay. So imagine
with your hands on the imaginary steering wheel that you
are in the center lane going thirty miles an hour,
and I want you to make a lane change into
your right lane. So go ahead and turn the wheel
(19:06):
in the way that you would to make a lane change. Now,
if you're like essentially everybody who I've ever tried this with,
what you do is you turn your wheel to the
right and then back to center. Is that what you did, Okay?
So that turns your car to the right, and now
you bump over the sidewalk and you crash into the buildings.
The way you make a lane change is by turning
(19:27):
the steering wheel to the right, then back through the center,
and just as far to the left and then you're
back to the center again. So if you're in a car,
pay attention to how you're doing this, and you'll see
that's how you make a lane change, and you do
it every day and you have no idea how you're
doing it. Why. It's because your unconscious brain is taking
(19:47):
care of all the details for you and you don't
even have access to what you're doing. So you can
do lots of things well with no consciousness involved. When
I was younger, I used to play baseball and my
coach would always say to us, I want you guys
to think out there. And I would say to him, actually,
you don't want us to think out there. You want
us to train a sufficient number of hours so that
(20:10):
we automatize all these behaviors and then we go out
there and perform. But the last thing you want us
doing out there is thinking, because we would never connect
the bat with the ball or catch the pop fly.
But he never believed me, so I had to go
become a neuroscientist and write books to convince him that
consciousness typically doesn't even get invited to the party. And
by the way, when consciousness does get any insight, it's
(20:33):
always the last one to hear the information. So think
about hitting a baseball. In twenty ten, the Guinness Book
of World Records clocked a fastball from the Cincinnati pitcher
or all this Chapman, at one hundred and five point
eight miles per hour. So if you work the numbers,
what you see is that Chapman's pitch left the mound
and cross the home plate in four tenths of a second,
(20:57):
four hundred milliseconds. What that means is there's just enough
time for light signals from the baseball to reach the
batter's eye work through the circuitry of the retina. Activate
these successions of cells along the loopy super highways of
the visual system at the back of the head, cross
the vast territories to the motor areas, and modify the
(21:19):
contraction of the muscles swinging the bat. And amazingly, this
entire sequence is possible in less than four tenths of
a second. Otherwise no one would ever hit a fastball.
But the surprising part is that conscious awareness takes longer
than that, at least half a second, so the ball
travels too rapidly for batters to be consciously aware of it.
(21:43):
And when I was playing baseball, my experience of hitting
the ball was always this. I would stand there ready
to swing, and then I would become consciously aware that
I had hit the ball and it was flying away
from me, and then I would say to myself, you
hit the ball, Now drop the bat and run. But
the actual moment of hitting the ball with the bat
(22:03):
was always moving way ahead of my slow consciousness, which
was the last one on the ladder to get any
of the news of what was transpiring. And all. This
is the case because you don't need to be consciously
aware to perform sophisticated motor acts. You can notice this
when you begin to duck from a snapping tree branch
(22:24):
before you are aware that is coming towards you, or
you're already jumping up by the time you realize that
your cell phone is ringing across the room. So these
examples about writing your signature backward, or changing lanes, or
hitting a baseball, these are a few among thousands. You
are not consciously aware of the vast majority of your
(22:46):
brain's ongoing activities, and nor would you want to be.
It would interfere with the brain's well oiled processes. The
best way to mess up your piano piece is to
concentrate on your fingers. The best way to get out
of breath is to think about your breathing. The best
way to miss your golf ball is to think too
much about your swing. And by the way, this wisdom
(23:08):
is apparent even to children. We find it immortalized in
poems like the Puzzled Centipede, which goes like this. A
centipede was happy quite until a frog in fun said,
pray tell which leg comes? After which this raised her
mind to such a pitch she lay distracted in the ditch,
(23:29):
not knowing how to run. So this ability to remember
how to do motor acts like changing lanes is called
procedural memory, and it's a type of implicit memory. Implicit
means that your brain holds the knowledge of something that
your conscious mind can't access, like riding a bike, or
(23:51):
tying your shoes, or typing on a keyboard, or steering
your car into a parking space while you're talking on
your cell phone. These are all examples of implicit memory.
You can execute these actions easily enough without having any
idea of exactly how you do it. You would be
totally unable to describe the perfectly timed choreography with which
(24:13):
your muscles contract and relax as you do these things,
or as you navigate around other people in a cafeteria
while you're holding a tray. But you don't have any
trouble doing any of these things. This is the gap
between what your unconscious brain can do and what you
can access consciously. To the extent that consciousness is useful,
(24:35):
it's useful in small quantities and for very particular kinds
of tasks. It's easy enough to understand why you wouldn't
want to be consciously aware of the intricacies of your
muscle movement, but this can be a little less intuitive
when applied to your perceptions and thoughts and beliefs, which
are also the final products of the activity of billions
(24:56):
of nerve cells. For a good example of this, can
consider chicken sexers. So what is a chicken sexer? Well,
when little chicken hatchlings are born, large commercial hatcheries divide
them up into males and females, and this practice of
figuring out which is which, of distinguishing the two genders,
(25:17):
this is known as chicken sexing. Now the hatcheries divide
them up because the two genders get different feeding programs.
The females who will eventually lay eggs are highly valued,
but sadly, most of the males are disposed of because
they don't produce eggs, and only a few males are
kept in fatten for meat. So anyway, the job of
(25:39):
the chicken sexor is to pick up each hatchling and
quickly determine its sex in order to choose the correct
bin to put it in. The problem is that this
task is famously difficult because female and male chicks look
exactly alike, well almost exactly. So the Japanese invented a
(26:01):
method of sexing chicks known as vent sexing, by which
expert chicken sexers could rapidly figure out the sex of
one day old hatchlings. So, beginning in the nineteen thirties,
poultry breeders from around the world traveled to the zen
Nippon Chick Sexing School in Japan to learn the technique.
The mystery was that no one could explain exactly how
(26:25):
it was done. It was somehow based on very subtle
visual cues, but the professional chick sexors could not report
what those cues were. Instead, they would look at the
chicks rear end where the vent is and simply seem
to know the correct bin to put it in. And
this is how the professionals taught the students. The master
(26:48):
would stand over the apprentice and watch the student would
pick up a chick, examine its rear, and put it
in one bin or the other, and the master would
give feedback yes or no. And after weeks on end
of this activity, the student's brain was trained up to
masterful levels that were totally unconscious. They could tell the
(27:12):
sects of the chicken, but they had no idea how
they were doing it. Meanwhile, a similar story was unfolding
on the other side of the world during World War Two.
Under a constant threat of bombings, the British had to
figure out how to distinguish incoming aircraft quickly and accurately.
Which aircraft were British planes coming home and which were
(27:34):
German planes coming to bomb. So, as it turns out,
there were several airplane enthusiasts who proved to be excellent spotters,
so the military eagerly employed their services. These spotters were
so valuable that the government quickly tried to enlist more spotters,
but they turned out to be very rare and difficult
to find. So what did the government do. They tried
(27:58):
to get the spotters to sit down and train other spotters,
but that turned out to be a total fail because
the spotters tried to explain their strategies but failed. No
one got it, not even the spotters themselves. Just like
the chicken sextors, the spotters had no idea how they
did what they did. They simply saw the right answer.
(28:22):
But with a little ingenuity, the British finally figured out
how to successfully train new spotters, and it was just
by trial and error feedback. So the novice would hazard
a guess and say I think that's a British plane
or I think that's a German plane, and the expert
would say yes or no, and eventually the novices became
(28:42):
like their mentors, vessels of this mysterious, ineffable expertise. So
there can be a really large gap between knowledge that
your brain has and your conscious awareness. So when we
(29:12):
examine skills that aren't available to introspection, like making a
lane change, or hitting the baseball or chicken sexing, the
first surprise is that your brain's unconscious memory for something
your implicit memory is totally separable from things that you
can talk about consciously or your explicit memory. You can
(29:33):
damage one without hurting the other. So, for example, sometimes
a person will get brain damage and get what's called
antaro grade amnesia, which means they can't consciously recall new
experiences in their lives. If you spend an afternoon trying
to teach a person like this the video game Tetris,
(29:55):
they'll tell you the next day that they have no
recollection of the experience. They've never seen this deo game before,
and most likely they don't have any idea who you
are either. But if you look at their performance on
the game the next day, you'll find that they have
improved exactly as much as a person without amnesia. In
other words, their brains have learned the game implicitly. The
(30:17):
knowledge is there, it's just that it's not accessible to
their consciousness. By the way, it's an interesting side note.
If you wake up an amnestic patient during the night
after they've played Tetris, they'll report to you that they
were dreaming of colorful falling blocks, but they have no
idea why. And of course it's not just checking sexors
(30:38):
and plane spotters and people with amnesia who enjoy unconscious learning. Essentially,
everything about your interaction with the world rests on this process.
You probably would have a difficult time putting into words
the characteristics of your father's walk, or the shape of
his nose, or the way that he laughs. When you
(31:00):
see someone who walks or looks or laughs like him,
you know it immediately. Now, I want to return to
this point that I mentioned at the beginning, which is
that you are your brain and this is why things
like brain damage can change you. But you don't need
brain damage to prove this to yourself. Just look at
the ways that you change when your biology changes. So
(31:22):
consider alcohol. You pour these invisibly small ethanol molecules into
your system, and that alters your perception and your behavior.
Your social inhibitions are lower, you feel freer, you think
your funnier at parties, you do more adventurous things. It's
just a molecule of a particular shape that interacts with
the membranes of your neurons. But it very slightly changes
(31:46):
the way that information flows through these giant networks, and
so who you are becomes slightly different. And drugs of
all sorts influence our behavior this is obvious with narcotics.
They slightly tweak the behavior of the network. And now
you're talking to silver leprechauns. And I'll give you another
(32:06):
interesting example of the influence of molecules. Take the professional
wrestler Chris Benoit, who was this giant muscley guy who
had a world heavyweight championship. And he went home one
night in two thousand and seven and he murdered his
wife and his son and he hung himself from one
of the pulleys of his weight machines. Now, at the autopsy,
(32:28):
they figured out he was on massive doses of the
steroid testosterone and other anabolic steroids, and these can cause
paranoia and violent outbursts, and it's known as roid rage.
You change the exact balance of chemicals under the hood,
and you change your decision making you change who you are.
(32:48):
And by the way, these kinds of changes and who
you are, these applied to prescription medications as well. Some
years ago, physicians began noticing that some of their patients
who had Parkinson's disease were becoming compulsive gamblers, and they
were blowing their families money in Las Vegas or Atlantic
City or online poker. Now, Parkinson's disease involves a decrease
(33:13):
in a neurotransmitter called dopamine, and so the medications to
help that they crank up dopamine levels and that makes
the tremors and the rigidity go away. But dopamine also
plays a second role in your brain, not just involving
how your muscles work, but also in your reward systems.
So it turns out that by ratcheting up the level
(33:35):
of dopamine it was changing the decision making of the patients.
It gave them a much bigger appetite for risk taking,
and one of the ways this expresses itself is with gambling.
So nowadays these Parkinson's medications come with a warning on
the label that if you notice an increase in gambling
or other risk taking behavior, then the dosage should be
(33:56):
turned down. So what's clear is that the soul I'm
total of your neurochemistry, whether from alcohol or drugs, or abuse,
or steroids or clinical medications, whatever, these modify your behavior.
So nowadays, what this all means is that when we
talk about morality and decision making, what we're really talking
(34:18):
about is the neural basis of this and this leads
us to the very deep question about freewill. Is the
mind separate from the brain or are they the same thing?
And because of all the cases we have of brain
damage and narcotics and disease states, and how people's behavior
changes when their brain changes, it's a very reasonable hypothesis
(34:41):
that you do not have free will. You are your brain.
And although it's a mind bogglingly complex system, it's nonetheless
a machine, a giant machine whose complexity we could never capture,
but a machine nonetheless. As far as we can tell,
every neuron that we measure is driven by the activity
of other neurons, and those are driven by the activity
(35:03):
of other neurons. So it's not even clear where that
extra bit of free will would even live, what would
make the whole machine not a machine. So try this.
Whatever your sexual orientation is, go ahead and switch it.
So if you're straight, become gay, and if you're gay,
go become straight. Go ahead, I'll wait, Okay, good luck, right,
(35:24):
Because free will isn't really what you might into it.
It's not like you just make a decision about something
consciously and then that's where things go. And this is
the same with addictions and cravings and temptations. You can't
just say, look, I'm the kind of person who doesn't
like cookies or sex or food or whatever, and then
that's how things go. There's a lot running under the
(35:44):
hood that you have no access to and no acquaintance with. Now.
I'm going to cover the free will question in much
more depth in future episodes, but for now, I just
want to say it's a bit of a difficult one
to answer. Do we have absolutely no free will? Do
we have a little bit of it? I think it's
fair to say that most neuroscientists land on the position
that we probably have none. Because every neuron in the
(36:06):
brain is driven by other neurons, then it's not clear
where you get the extra bit. I just want a
flag that, given the available data, I think it's probably
too early for us to conclude on this point with
absolute certainty, because our science is still quite young. But
what is absolutely clear is that if we have any
free will at all, it is just a bit player
(36:27):
in the system. The unconscious brain is the one in charge,
and the conscious you is not driving the boat. So
even if there is just a little bit of free will,
just about everything you think and do and act and
believe is generated by parts of your brain that are
doing their own thing. Okay, so let's wrap up. What
(36:48):
we've done in this episode is set up some foundational
issues about how little we have access to what's running
in our brains, all the activity that determines who we
are and how we act what we believe. So join
me next week for part two, where we'll ask how
all this could or should affect the legal system. If
(37:09):
we don't have free will or very little of it,
what does that mean for the notion of culpability? In
what sense are we responsible for our actions when there's
so much running under the hood and so little conscious choice.
We can't not take bad actors off the street, but
how do we reconcile these two fields of neuroscience and
(37:31):
legal theory. To find out more and to share your thoughts,
head to Eagleman dot com, slash Podcasts, and you can
also watch full episodes of Inner Cosmos on YouTube at
inner cosmospod subscribe to see new episodes every week until then.
(37:53):
This is David Eagleman signing off from the Inner Cosmos
Host
David Eagleman
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