Translator: hila scherba Reviewer: Emma Gon
Have you ever looked into the star filled night sky
and been in awe at the enormity of it all
and felt really small and wondered what's going to happen when you die?
Well, I remember when I first had this experience, I was just 5 years old.
I lay awake all night, looking up into the night sky,
and I'd realized for the first time that one day I would cease to exist.
And then I thought,
"Well, even if my body doesn't exist, and I can't communicate to anyone else,
can I at least still keep my own inner thoughts
and have my own inner world?
So the next day, I asked my father, who is a physician, I said,
"Dad, where do my thoughts come from? How can I keep them when I die?"
and he said, "Well, they come from your brain."
I said, "Well how?" He said, "Actually, we don't know."
So I said, "What can I be when I grow up,
so I can understand where my thoughts come from?"
and he said, "From the medical world view, you can be a psychiatrist."
So, that became my life long quest, not to become a psychiatrist,
but to try to understand how my brain produces
my thoughts, my emotions, my sensations.
How it is that this amazingly complex,
but just, very small, three-pound piece of matter,
all the neurons firing and neurochemical slushing around -
how does it produce the subjective feeling of, say, smelling a rose
or the beautiful colors you see in a sunset
or even when you just close your eyes and imagine a beautiful sunset,
that image in your mind?
How do those neurons firing create that subjective experience
or the emotions you feel,
like when you see your newborn child for the first time -
I just had my beautiful daughter; she's one year old now -
or when you hear a beautiful piece of music that moves you? (Music)
You know, the sound waves are hitting your eardrums;
they're being processed by your auditory cortex.
But something is happening in your brain that you're perceiving the music.
So where does that take place?
When you're looking at a beautiful image,
the photons of light are hitting you retina,
they're being processed by your visual cortex.
But then there's something in that;
something happens that perception takes place.
So what's happening?
To really understand this we need to look a little more closely at the brain.
The basic unit of the nervous system is the neuron.
It's a fairly complex cell,
but its basic job is simply to transmit electrical and chemical signals.
The human brain has 86 to 100 billion neurons.
Each one of those neurons
has around 1,000 to 10,000 synapses or connections.
So that means, that there are about 100 trillion connections
in the human brain.
There are more connections in the human brain
than there are stars in the Milky Way.
Think about that.
So we have a whole inner cosmos inside of our head.
The brain is basically like an information processing machine.
Everything that you experience
from the moment you wake up from a deep dreamless sleep,
until you go back to sleep again, or into a coma, or death -
everything you experience, thoughts, your emotions, your sensations -
they are all being encoded in these neurons firing,
in this information processing machine.
But, what's really interesting
is that much of what's happening in your brain
is actually happening outside of awareness.
It's a myth that we only use 10% of our brain;
we actually use all of our brain; none of it is redundant.
But we're only conscious of very little bit of it.
But much of what's happening
that's affecting decisions you're making, your behavior,
it's happening because of processes that are occurring unconsciously,
outside of awareness.
So how can we measure this in the lab?
Well, we can give you stimuli, like this one, for example,
that is either presented in such a subtle form,
or things that are presented so quickly
that a person claims they didn't see anything,
yet it goes on to affect their behavior.
Here, for example, there is a hidden message.
Raise your hand if you can see it.
A couple of people, OK.
I know what you're thinking now.
In the background, in the negative space, it says S-E-X, right here, see that?
(Laughter) Yeah.
And there are the birds and the bees,
and the flowers are kind of loving towards each other.
Now, once you see it, you can't unsee it.
If I show you this in an hour, you'll see it right away,
something changed in your brain.
What's interesting is that the stimulus stayed exactly the same;
the lines and the colors hitting your retina
being processed by your visual part of your brain;
all stayed the same, but what changed was in your mind, was your perception.
What's out there in reality,
doesn't necessarily correlate with what you perceive.
Here's another example, if you look at square A versus square B,
you would swear that they're different colors, different shades,
but this is an illusion; it's the shadow illusion,
because if I remove the shadow and just put a line,
you can see they're actually exactly the same color.
So you brain makes approximations all the time.
If we had to process every single stimuli in the environment,
it would be too much because consciousness has a limited capacity,
but the unconscious is vast, in fact, we still haven't found its limits.
Here is another example.
Here it looks as if the circle in the middle is changing in shape,
but it's actually staying the same size the whole time.
Again, what's out there in reality
doesn't necessarily correlate with what you perceive.
I think the Gorillaz once said it nicely:
"You don't see with you eyes; you perceive with you mind."
It's all in your head.
Here's one more example.
This, you can either perceive it as an old woman looking down,
or as a young woman looking away,
and you never perceive them both at the same time, right?
And what's interesting here is the stimulus stays the same
but what's changing is your perception in your brain.
So that's what we want to track - the neural correlates of perception.
What we know from neuroscience is that it seems to be
that what correlates with your perception
are these coalitions of neurons firing together.
If you think of it like a parliament, and you have these competing factions,
some groups always kind of vote together and suppress the competing coalitions.
That's sort of what it's like.
It's like a Darwinian competition between neurons in your brain.
Or you can think of it like when something is trending on social media,
like if each tweet is like you're voting for something.
After a certain amount of time, enough tweets will cause something to trend.
And that's kind of what comes into consciousness
until something else takes over.
So these things, these coalitions, stay in power for a fraction of a second
to a few seconds.
If you attend to something you can keep it in consciousness longer,
and then you might ask, what brings these neurons together.
Another metaphor for it is that it's kind of like an orchestra.
If each player is like a neuron;
it's not like they're all playing the same note,
that would be like an epileptic seizure,
but, they're also not playing in the beginning, warming up,
playing different notes.
But when they're playing a symphony, when they're all playing in harmony,
that's what it's like when these coalitions come together.
Also in the brain there seems to be these two, roughly speaking, systems.
You have these areas in red, these evolutionarily older parts of you brain,
the sub-cortical area, sometimes called your reptilian brain,
or called the limbic system, that's really sensitive
to immediate pleasure, immediate rewards and punishers.
Freud would call it your id impulses,
"I want the piece of chocolate cake right now!"
And it gives you that little high when you get something rewarding.
In rats, when we implanted electrodes into those sub-cortical areas,
and they allowed them to self stimulate directly to the reward center,
they would press the lever and self stimulate
over food if they're food deprived, water if they're water deprived,
to the point of exhaustion, so it's a really powerful drive.
But then you have another part of the brain,
called the prefrontal cortex, these areas here, in blue,
that's the more recently evolved part of the brain,
and humans actually have a larger percent compared to the rest of the brain,
of prefrontal cortex than any other species.
This part of your brain, kind of called the "executor,"
thinks about the future consequences of your actions,
the long term consequences.
So there is this rivalry; so you might say,
"I want that piece of chocolate cake now."
But then the prefrontal cortex,
or Freud would call your super ego would say,
"Oh, maybe I want to look good in a bikini, maybe I shouldn't."
When there is an imbalance, though, between these two,
if you think of the sub-cortical area like an accelerator pushing you forward,
the prefrontal cortex is like the brake, but if there's too much acceleration,
or the brake isn't working properly,
then it can cause all sorts of impulse control disorders, different problems.
For instance, if there is a lesion or damage to the prefrontal cortex,
or the brake system, it can cause you to act out impulsively.
And this was one of the first cases to show that.
In the 1850's this man, Phineas Gage, was working on a railroad.
There was an explosion and this iron rod went straight
through his prefrontal cortex,
and he had a complete change of personality.
He went from being a mild mannered man to being impulsive and aggressive,
and this was the foundation of the idea
that this part of the brain had to do with impulse control.
What was really interesting is other aspects of his cognition remained intact,
like his memory, his intellect, his ability to sense different things;
it was very specific to impulse control.
So then you might ask,
"What does that mean? What about my free will?
If I am just my brain, and you can damage it,
how much control do I really have?"
So, the classic definition of free will
is that you're free if under the exact same circumstances, and that means,
everything in the environment was exactly the same,
and every neuron firing in your brain was exactly the same,
so in that case, for example, Neo in "The Matrix,"
he could have chosen the blue pill,
if everything in his environment was exactly the same, as the red pill.
So he could have lived in blissful ignorance,
but no, he chose the red pill.
According to neuroscience, at least our studies show
that if everything in your brain is exactly the same,
and everything in the environment is the same, you can't choose differently.
Our sense of free will is a bit of an illusion;
it comes after the fact; the brain decides first and we're aware of it after.
Studies show, for example, we can predict with neuroimaging techniques
up to 10 seconds, just looking at brain activation,
before you become consciously aware of your intention to go left or right.
So the brain is what's deciding first.
So free will is sort of an illusion, but it's an important illusion,
because behavioral studies show
that if you diminish a person's belief in free will,
they're more likely to act unethically and unkindly;
they're more likely, for example, to cheat on a math test.
So it's an important illusion to have,
and, the other thing is, you can't just go out there
and say, "Well, I have no free will. Now I can go out and act impulsively,"
because we hold people responsible for their actions
to the extent that they have self control.
Self control is an evolved part of the brain,
and we all have the ability to do it to different extent.
But self control develops over a lifetime.
So that's why, for example, there are different judicial consequences
for a person who commits a crime
at 5 years old versus a teenager versus a young adult.
Because the brain actually isn't fully mature until around the age 25.
In particular, the prefrontal cortex, that brake system, isn't fully developed
until around the age 25.
So you take an adolescent brain and they have an under mature brake system.
In addition, they have a hyper sensitive limbic system,
that subcortical reptilian brain I was talking about,
so they're much more sensitive to immediate rewards.
And there is a big surge of hormones,
so it's no wonder that adolescents tend to be more risk taking,
a bit more moody and lack impulse control.
And there are also individual differences in impulse control.
In fact, there's this "Marshmallow test."
They give it to kids who are 3 to 6 years old,
and say "You can either have one marshmallow now,
or wait and have two later."
And simply their ability to wait to have two marshmallows later,
at the age around 3 and 6, predicted all these lifelong consequences,
SAT scores, their job attainment, their health, even their body mass index.
You might say, "What can I do? How can I improve my impulse control?"
The good news is that the brain is actually changing throughout life;
we call it neuroplasticity.
But there are certain critical periods of development,
where if you expose a person to certain environmental stimuli,
it could really have a big impact on how the brain develops,
and youth is a very malleable time.
So strategies that people can do to help improve their self control,
one strategy is to be mindful.
So when you're in a situation you think you might behave impulsively,
stop, count to ten, take a deep breath, be aware of your surroundings,
like for instance now, take a moment and just listen to the sounds of the room.
Now you're mindful of that.
The opposite of mindful is mind empty.
That'd be like when you're in the movie theater,
you're just eating popcorn, all of sudden, you look down, it's gone;
you're on auto pilot.
But, when you're mindful
of what's happening in your body and externally,
and it can help, maybe,
to take a moment to bring the prefrontal cortex online.
Another strategy is to change your environment.
Know what your predilections are; know what your impulses are.
If you have a sweet tooth, don't put sweet things around the house,
don't put them in full view, or don't have them in the house at all.
If you're breaking up with someone, take their number out of your phone,
or tell your friends not to give you their number.
Just changing your environment can help you change your behavior.
And finally, we often think of our future selves
as being a bit better than our current selves,
so we're more likely to commit to something now
that doesn't start till later.
For example, we're more likely to sign up for a gym
if the membership doesn't start till a month from now.
And also put social pressure in place, maybe there can be an app that says,
"so and so didn't go to the gym today,"
or you have to meet you friend at the gym, and you don't want to embarrass yourself.
All these things, eventually, if you change your behavior,
it will become automatic over time, and it will change your brain.
It's also not all bad.
The youth brain might be a little bit more impulsive,
but studies show that it could be
that they might have more propensity to be more playful and creative.
Studies were done that looked at the brain of a rap artist
when they were doing freestyle rap or jazz musicians
when they were improvising,
and they found a similar pattern of activation.
So when they were improvising, they had decreased activation
in a part of the brain that had to do with self awareness, self consciousness,
and making sure that your behavior conforms to social norms,
they had increased activation in part of the prefrontal cortex
that had to do with the internal generation of new ideas.
So they were in this state of mind where they're generating new ideas,
and it was unfiltered, they were allowed to make novel associations between things
without being judged.
And it's like anything,
when you're in the flow, when you're in the moment,
the second you become self aware, it can mess up your behavior.
Like a tennis player, if they're playing and they start thinking -
"Exactly what angle should I hit this ball?"
they're going to mess it up.
So people really try to achieve this flow state,
and it could be that the adolescent brain,
because their under mature prefrontal cortex,
they might have less filtering and more ability to be creative and spontaneous.
It's not just improvisation; there are other states of mind
that show a similar brain activation, similar pattern of this flow state.
For example, during hypnosis, during daydreaming, during meditation
or REM sleep where people lose their sense of self, of time, of place;
it's a free flow of thoughts, perhaps bubbling up from the unconscious
that's no longer suppressed,
and it's associated with really positive emotions.
The more that I've explored and the more that I learned,
the more I really realized how much we don't understand
about the brain, and about consciousness and the unconscious.
We still need an overarching theory of consciousness, so we can determine:
Does a baby in utero have it? Does a bee have it?
Does a computer have it? Does the Internet have it?
We need an overarching theory.
But with the knowledge that we have so far,
what we can take from that
is that we should perhaps try to look inward
and try to understand our own conscious, unconscious drives
and motivations and fears, and bring it to the surface.
That's what things like psychotherapy can do,
or dream analysis, or even during improvisation.
The more we can understand our own unconscious,
the more we can perhaps live more in line with our long term goals and be happy.
There is this saying; it's written on the Temple of Apollo at Delphi;
it was written by the ancient Greeks in the 7th century BC,
and it's also, if you look really closely,
it's hanging on the Oracle's kitchen in "The Matrix,"
and it says, "Know Thyself."
And ultimately that will hopefully lead to wisdom,
which is just having knowledge and experience and good judgment.
I started out studying consciousness
in order to find a way for my thoughts to survive death.
But what I got instead was just a sense of feeling of awe
that this three pound piece of matter
could even ask these kind of questions and contemplate the answers.
So the question still exists:
How does my subjective experience arise out of matter?
Carl Sagan said that we are the cosmos' way for to know itself.
It's extraordinary, and with the modern technology that we have today,
it allows us to peer even deeper into the brain
than was even possible when I was 5 years old.
So that makes me really optimistic that maybe,
the next generation of neuroscientists -
which could be some of you right here - could maybe finally unlock this mystery.
Thank you.
(Applause)