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  • 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 placing 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 over here

  • 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 high-order 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 day after day after day

  • to different media channels, like Fox News or The New York Times,

  • that give us very different perspectives