-
Imagine that you invented a device
-
that can record my memories,
-
my dreams, my ideas,
-
and transmit them to your brain.
-
That would be a game-changing
technology, right?
-
But in fact, we already
possess this device,
-
and it's called human communication system
-
and effective storytelling.
-
To understand how this device works,
-
we have to look into our brains.
-
And we have to formulate the question
in a slightly different manner.
-
Now we have to ask
-
how these neuron patterns in my brain
-
that are associated
with my memories and ideas
-
are transmitted into your brains.
-
And we think there are two factors
that enable us to communicate.
-
First, your brain is now
physically coupled to the sound wave
-
that I'm transmitting to your brain.
-
And second, we developed
a common neural protocol
-
that enabled us to communicate.
-
So how do we know that?
-
In my lab in Princeton,
-
we bring people to the fMRI scanner
and we scan their brains
-
while they are either telling
or listening to real-life stories.
-
And to give you a sense
of the stimulus we are using,
-
let me play 20 seconds
from a story that we used,
-
told by a very talented storyteller,
-
Jim O'Grady.
-
(Audio) Jim O'Grady: So I'm banging out
my story and I know it's good,
-
and then I start to make it better --
-
(Laughter)
-
by adding an element of embellishment.
-
Reporters call this "making shit up."
-
(Laughter)
-
And they recommend
against crossing that line.
-
But I had just seen the line crossed
between a high-powered dean
-
and assault with a pastry.
-
And I kinda liked it."
-
Uri Hasson: OK, so now
let's look into your brain
-
and see what's happening
when you listen to these kinds of stories.
-
And let's start simple -- let's start
with one listener and one brain area:
-
the auditory cortex that processes
the sounds that come from the ear.
-
And as you can see,
in this particular brain area,
-
the responses are going up and down
as the story is unfolding.
-
Now we can take these responses
-
and compare them to the responses
in other listeners
-
in the same brain area.
-
And we can ask:
-
How similar are the responses
across all listeners?
-
So here you can see five listeners.
-
And we start to scan their brains
before the story starts,
-
when they're simply lying in the dark
and waiting for the story to begin.
-
As you can see,
-
the brain area is going up and down
in each one of them,
-
but the responses are very different,
-
and not in sync.
-
However, immediately
as the story is starting,
-
something amazing is happening.
-
(Audio) JO: So I'm banging out my story
and I know it's good,
-
and then I start to make it --
-
UH: Suddenly, you can see
that the responses in all of the subjects
-
lock to the story,
-
and now they are going up and down
in a very similar way
-
across all listeners.
-
And in fact, this is exactly
what is happening now in your brains
-
when you listen to my sound speaking.
-
We call this effect "neural entrainment."
-
And to explain to you
what is neural entrainment,
-
let me first explain
what is physical entrainment.
-
So, we'll look and see five metronomes.
-
Think of these five metronomes
as five brains.
-
And similar to the listeners
before the story starts,
-
these metronomes are going to click,
-
but they're going to click out of phase.
-
(Clicking)
-
Now see what will happen
when I connect them together
-
by pressing them on these two cylinders.
-
(Clicking)
-
Now these two cylinders start to rotate.
-
This rotation vibration
is going through the wood
-
and is going to couple
all the metronomes together.
-
And now listen to the click.
-
(Synchronized clicking)
-
This is what you call
physical entrainment.
-
Now let's go back to the brain and ask:
-
What's driving this neural entrainment?
-
Is it simply the sounds
that the speaker is producing?
-
Or maybe it's the words.
-
Or maybe it's the meaning
that the speaker is trying to convey.
-
So to test it, we did
the following experiment.
-
First, we took the story
and played it backwards.
-
And that preserved many
of the original auditory features,
-
but removed the meaning.
-
And it sounds something like that.
-
(Audio) JO: (unintelligible)
-
And we flashed colors in the two brains
-
to indicate brain areas that respond
very similarly across people.
-
And as you can see,
-
this incoming sound induced entrainment
or alignment in all of the brains
-
in auditory cortices
that process the sounds,
-
but it didn't spread
deeper into the brain.
-
Now we can take these sounds
and build words out of it.
-
So if we take Jim O'Grady
and scramble the words,
-
we'll get a list of words.
-
(Audio) JO: ... an animal ...
assorted facts ...
-
and right on ... pie man ...
potentially ... my stories
-
UH: And you can see that these words
start to induce alignment
-
in early language areas,
but not more than that.
-
Now we can take the words
and start to build sentences out of them.
-
(Audio) JO: And they recommend
against crossing that line.
-
He says: "Dear Jim,
Good story. Nice details.
-
Didn't she only know
about him through me?"
-
UH: Now you can see that the responses
in all the language areas
-
that process the incoming language
-
become aligned or similar
across all listeners.
-
However, only when we use
the full, engaging, coherent story
-
do the responses spread
deeper into the brain
-
into higher-order areas,
-
which include the frontal cortex
and the parietal cortex,
-
and make all of them
respond very similarly.
-
And we believe that these responses
in higher-order areas are induced
-
or become similar across listeners
-
because of the meaning
conveyed by the speaker,
-
and not by words or sound.
-
And if we are right,
there's a strong prediction of???
-
if I tell you the exact same ideas
-
using two very different sets of words,
-
your brain responses
will still be similar.
-
And to test it, we did
the following experiment in my lab.
-
We took the English story
-
and translated it to Russian.
-
Now you have two different sounds
and linguistic systems
-
that convey the exact same meaning.
-
And you play the English story
to the English listeners
-
and the Russian story
to the Russian listeners,
-
and we can compare their responses
across the groups.
-
And when we did that, we didn't see
responses that are similar
-
in auditory cortices in language,
-
because the language
and sound are very different.
-
However, you can see
that the responses in other areas
-
were still similar
across these two groups.
-
We believe this is because they understood
the story in a very similar way,
-
as we confirmed, using a test
after the story ended.
-
And we think that this alignment
is necessary for communication.
-
For example, as you can tell,
-
I am not a native English speaker.
-
I grew up with another language,
-
and the same might be for many
of you in the audience.
-
And still, we can communicate.
-
How come?
-
We think we can communicate
because we have this common code
-
that presents meaning.
-
So far, I've only talked about
what's happening in the listener's brain,
-
in your brain, when
you're listening to talks.
-
But what's happening
in the speaker's brain, in my brain,
-
when I'm speaking to you?
-
To look in the speaker's brain,
-
we asked the speaker
to go into the scanner,
-
we scan his brain,
-
and then compare his brain responses
to the brain responses of the listeners
-
listening to the story.
-
You have to remember that producing speech
and comprehending speech
-
are very different processes.
-
Here we're asking: How similar are they?
-
To our surprise,
-
we saw that all these complex
patterns within the listeners
-
actually came from the speaker brain.
-
So production and comprehension
rely on very similar processes.
-
And we also found
-
the stronger the similarity
between the listener's brain
-
and the speaker's brain,
-
the better the communication.
-
So I know that if you
are completely confused now,
-
and I do hope that this is not the case,
-
your brain responses
are very different than mine.
-
But I also know that if you really
understand me now,
-
then your brain ...and your brain
... and your brain
-
are really similar to mine.
-
Now, let's take all
this information together and ask:
-
How can we use it to transmit
a memory that I have
-
from my brain to your brains?
-
So we did the following experiment.
-
We let people watch,
for the first time in their life,
-
a TV episode from the BBC series
"Sherlock," while we scanned their brains.
-
And then we asked them
to go back to the scanner
-
and tell the story to another person
that never watched the movie.
-
So let's be specific.
-
Think about this exact scene,
-
when Sherlock is entering
the cab in London
-
driven by the murderer he is looking for.
-
With me, as a viewer,
-
there is a specific brain pattern
in my brain when I watch it.
-
Now, the exact same pattern,
I can reactivate in my brain again
-
by telling the world:
Sherlock, London, murderer.
-
And when I'm transmitting
these words to your brains now,
-
you have to reconstruct it in your mind.
-
In fact, we see that pattern
emerging now in your brains.
-
And we were really surprised to see
-
that the pattern you have
now in your brains
-
when I'm describing to you these scenes
-
would be very similar to the pattern
I had when I watched this movie
-
a few months ago in the scanner.
-
This starts to tell you
about the mechanism
-
by which we can tell stories
and transmit information.
-
Because, for example,
-
now you're listening really hard
and trying to understand what I'm saying.
-
And I know that it's not easy.
-
But I hope that at one point
in the talk we clicked, and you got me.
-
And I think that in a few hours,
a few days, a few months,
-
you're going to meet someone at a party,
-
and you're going to tell him
about this lecture,
-
and suddenly it will be as if
he is standing now here with us.
-
Now you can see
how we can take this mechanism
-
and try to transmit memories
and knowledge across people,
-
which is wonderful, right?
-
But our ability to communicate
relies on our ability
-
to have common ground.
-
Because, for example,
-
if I'm going to use the British synonym
-
"hackney carriage" instead of "cab,"
-
I know that I'm going to be misaligned
with most of you in the audience.
-
This alignment depends
not only on our ability
-
to understand the basic concept;
-
it also depends on our ability to develop
common ground and understanding
-
and shared belief systems.
-
Because we know that in many cases,
-
people understand the exact
same story in very different ways.
-
So to test it in the lab,
we did the following experiment.
-
We took a story by J.D. Salinger,
-
in which a husband lost track
of his wife in the middle of a party,
-
and he's calling his best friend, asking,
"Did you see my wife?"
-
For half of the subjects,
-
we said that the wife was having
an affair with the best friend.
-
For the other half,
-
we said that the wife is loyal
and the husband is very jealous.
-
This one sentence before the story started
-
was enough to make the brain responses
-
of all the people that believed
the wife was having an affair
-
be very similar in these high-order areas,
-
and different than the other group.
-
And if one sentence is enough
to make your brain similar
-
to people that think like you
-
and very different than people
that think differently than you,
-
think how this effect is going
to be amplified in real life,
-
when we are all listening
to the exact same news item
-
after being exposed
days after day after day
-
to different media channels,
like Fox News or The New York Times,
-
that give us very different
perspectives on reality.
-
So let me summarize.
-
If everything worked as planned tonight,
-
I used my ability to vocalize sound
to be coupled to your brains.
-
And I used this coupling
-
to transmit my brain patterns associated
with my memories and ideas
-
into your brains.
-
In this, I start to reveal
the hidden neural mechanism
-
by which we communicate.
-
And we know that in the future
it will enable us to improve
-
and facilitate communication.
-
But these studies also reveal
-
that communication relies
on a common ground.
-
And we have to be
really worried as a society
-
if we lose this common ground
and our ability to speak with people
-
that are slightly different than us
-
because we let a few very strong
media channels
-
take control of the mike,
-
and manipulate and control
the way we all think.
-
And I'm not sure how to fix it,
because I'm only a scientist.
-
But maybe one way to do it
-
is to go back to the more
natural way of communication,
-
which is a dialogue,
-
in which it's not only me
speaking to you now,
-
but a more natural way of talking,
-
in which I am speaking and I am listening,
-
and together we are trying to come
to a common ground and new ideas.
-
Because after all,
-
the people we are coupled to
define who we are.
-
And our desire to be coupled
to another brain
-
is something very basic
that starts at a very early age.
-
So let me finish with an example
from my own private life
-
that I think is a good example
of how coupling to other people
-
is really going to define who we are.
-
This my son Jonathan at a very early age.
-
See how he developed
a vocal game together with my wife,
-
only from the desire and pure joy
of being coupled to another human being.
-
(Both vocalizing)
-
(Laughter)
-
Now, think how the ability of my son
-
to be coupled to us
and other people in his life
-
is going to shape the man
he is going to become.
-
And think how you change on a daily basis
-
from the interaction and coupling
to other people in your life.
-
So keep being coupled to other people.
-
Keep spreading your ideas,
-
because the sum of all of us
together, coupled,
-
is greater than our parts.
-
Thank you.
-
(Applause)
Brian Greene
This transcript was updated on 8/17/16.
At 9:11, the phrase "by telling the world" was changed to "by telling the word."