Speaker 1: In the last episode, I tackled the question of whether
Speaker 1: we could really know what it's like to be someone else,
Speaker 1: as in empathize with them so completely that we actually
Speaker 1: really understand what it is to be in their shoes. Today,
Speaker 1: we're going to ask could technology help us to get there?
Speaker 1: Could we have dreams celebrities in which some people upload
Speaker 1: their dreams and other people watch them and a dream
Speaker 1: can go viral? How am I going to explain what
Speaker 1: consciousness actually feels like through four movies that got it wrong?
Speaker 2: Why don't you see your own blinks?
Speaker 1: What would it be like to numb exactly one half
Speaker 1: of your brain with barbituates? And what would it be
Speaker 1: like to become a horse? Welcome to Intercosmos with me
Speaker 1: David Eagelman. I'm a neuroscientist and author at Stanford and
Speaker 1: in these episodes we sail deeply into our three pound
Speaker 1: universe to understand why and how our lives look the
Speaker 1: way they do. Today's episode is about the question of
Speaker 1: whether we can ever really know what it is like
Speaker 1: to be someone else. In the last episode, we discussed
Speaker 1: why we humans are all so different on the inside
Speaker 1: and whether it's possible that the gaps are unbridgable, and
Speaker 1: we examine this from the point of view of neuroscience
Speaker 1: and philosophy and literature. But today we're going to turn
Speaker 1: to the angle of technology. Could new technology ever allow
Speaker 1: us to better understand other people? So let's start with
Speaker 1: an old movie that I saw back in nineteen ninety five.
Speaker 1: The movie is called Strange Days, and it explores the
Speaker 1: idea of wearing this special helmet, and the helmet records
Speaker 1: the activity in your brain, all of your memories, your feelings,
Speaker 1: your thoughts. It records that, and the recorded event is
Speaker 1: frozen in time on a data disk. It's like an
Speaker 1: MP four file, but one that captures not just audio
Speaker 1: and video but everything. And then another person can put
Speaker 1: on the helmet and they can experience it all. They
Speaker 1: remember your memories, they feel your feelings, they think your
Speaker 1: thoughts in that moment. In other words, you can live
Speaker 1: a moment in the life of another person, and you
Speaker 1: can also live the same moment of your life more
Speaker 1: than once. So in the movie, a guy named Lenny
Speaker 1: Nero is a former police officer who now works as
Speaker 1: a playback artist in Los Angeles and ends up finding
Speaker 1: a recording of a woman's last moments alive, and he
Speaker 1: becomes involved in a murder investigation, and this leads him
Speaker 1: to a group of people who are planning a terrorist attack,
Speaker 1: and so he has to use his skills as a
Speaker 1: playback artist to stop the attack and save the city. Okay,
Speaker 1: but here's the part I want to concentrate on. Could
Speaker 1: a helmet like this be possible? Could we get our
Speaker 1: neurotechnology to a point where you could record one person's
Speaker 1: experience and have a second person live it. And while
Speaker 1: we're holding that question, I want to give a related example.
Speaker 1: Some years ago, a futurist named Michael Andisimov proposed the
Speaker 1: idea of dream celebrities. The idea here was that someday
Speaker 1: in the future, presumably using nano robotics, people would be
Speaker 1: able to record and upload their dreams and then other
Speaker 1: people could watch them. So, could these versions of the
Speaker 1: future be possible even though people are so different on
Speaker 1: the inside, Could we leverage this imaginary futuristic tech in
Speaker 1: this way to know what it is like to be
Speaker 1: someone else? Now, I'm not speaking of this just in
Speaker 1: terms of empathy, which I talked about in the last episode,
Speaker 1: but in terms of uploading the experience of one person
Speaker 1: and then downloading it into the head of another. So
Speaker 1: let's start today's journey with an idea that I started
Speaker 1: chewing on a very long time ago when I was
Speaker 1: in graduate school and learned about a medical procedure called
Speaker 1: the Wata test WADA. Now, this is something that was
Speaker 1: commonly used before brain surgery when the neurosurgeon is trying
Speaker 1: to determine which side of the brain, which hemisphere is
Speaker 1: responsible for language, because you want to make sure, as
Speaker 1: the surgeon, not to damage critical areas involved in speech.
Speaker 1: So what you do is inject a sedative, usually sodium
Speaker 1: amma barbitol, into one hemisphere of the brain and that
Speaker 1: hemisphere essentially goes to sleep for about five or ten minutes,
Speaker 1: while the other hemisphere, the other half of your brain,
Speaker 1: remains active. And this is what allows the neurosurgeon to
Speaker 1: test which side of the brain is dominant for language.
Speaker 1: While one half of the brain is anesthetized, the patient
Speaker 1: is asked to speak, to count, to name objects, to
Speaker 1: follow commands, to recognize pictures, and you see if language
Speaker 1: is impaired, and if so, then whichever hemisphere is anesthetized
Speaker 1: is the one dominant for speech. Now, after the barbiturate
Speaker 1: wears off, wham, then you do it on the other side,
Speaker 1: putting the other half of the brain to sleep and
Speaker 1: testing everything again. Now you might say, isn't language always
Speaker 1: in the left hemisphere. No, it's about fifty to fifty
Speaker 1: for left handed people. But also some people have a
Speaker 1: typical brain organization, for example, if they've had early brain injuries,
Speaker 1: so their language areas might end up in the right
Speaker 1: hemisphere instead of the left. So this is why you
Speaker 1: really want to make sure you know where language is
Speaker 1: before you go cutting around in the brain, because obviously
Speaker 1: one of the worst things you can do to somebody
Speaker 1: is damage their ability to communicate with the outside world. Okay,
Speaker 1: so what I told you is that this water test
Speaker 1: temporarily shuts down one hemisphere at a time so that
Speaker 1: you can assess things. Now, the first time I heard
Speaker 1: about this as a student, I wondered if it would
Speaker 1: be possible to repurpose and expand this technique. For example,
Speaker 1: a cat's brain is a lot like ours, except that
Speaker 1: we have an enormous cerebrum while they have a larger cerebellum.
Speaker 1: So could you put a very specific pattern of sedatives
Speaker 1: into the brain in just the right regions to mold
Speaker 1: your brain to be like a cat's. Now, this is
Speaker 1: just fantasy, of course, no one's ever done this, and
Speaker 1: it's hard to know.
Speaker 2: How you would even know if you're doing it right.
Speaker 1: If I do something and I get a very strange feeling,
Speaker 1: how can I ever know that that's exactly what a
Speaker 1: cat feels, as opposed to just some other interesting, weird feeling. Nonetheless,
Speaker 1: you could get closer in theory than you might otherwise.
Speaker 1: But there's a fundamental problem with this idea. And I
Speaker 1: was chewing on this many years ago, and this became
Speaker 1: the intellectual seed for one of my short stories in
Speaker 1: my book some called Descent of Species. Now, I read
Speaker 1: this story on the podcast about a year and a
Speaker 1: half ago, but I'm going to read it again now
Speaker 1: for a different purpose. And I'd like you to keep
Speaker 1: your ears out for what the problem is about turning
Speaker 1: your brain into someone else's. So here's the story descentive
Speaker 1: Species from some in the afterlife, you are treated to
Speaker 1: a generous opportunity. You can choose whatever you would like
Speaker 1: to be in the next life. Would you like to
Speaker 1: be a member of the opposite sex, born into royalty
Speaker 1: a philosopher with bottomless profundity, a soldier facing triumphant battles.
Speaker 1: But perhaps you've just returned here from a hard life.
Speaker 1: Perhaps you were tortured by the enormity of the decisions
Speaker 1: and responsibilities that surrounded you. And now there's only one
Speaker 1: thing you yearn for, simplicity that's permissible. So for the
Speaker 1: next round, you choose to be a horse. You covet
Speaker 1: the bliss of that simple life afternoons of grazing in
Speaker 1: grassy fields, the handsome angles of your skeleton and the
Speaker 1: prominence of your muscles, the piece of the slow flicking tail,
Speaker 1: or the steam rifling through your nostrils. As you lope
Speaker 1: across snow blanketed planes. You announce your decision. Incantations are muttered,
Speaker 1: a wand is waved, and your body begins to metamorphose
Speaker 1: into a horse. Your muscles start to bulge, A mat
Speaker 1: of strong hair erupts to cover you like a comfortable
Speaker 1: blanket in winter. The thickening and lengthening of your neck
Speaker 1: immediately feels normal as it comes about. Your carotid arteries
Speaker 1: grow in diameter, your fingers blend hoofward, your knees stiffen,
Speaker 1: your hips strengthen, and meanwhile, as your skull lengthens into
Speaker 1: its new shape, your brain races in its changes. Your
Speaker 1: cortex retreats as your cerebellum grows, the homunculus melts man
Speaker 1: to horse. Neurons redirect, synapses, unplug and replug on their
Speaker 1: way to equestrian patterns, and your dream of understanding what
Speaker 1: it is like to be a horse gallops towards you
Speaker 1: from the distance. Your concern about human affairs begins to
Speaker 1: slip away, your cynicism about human behavior melts, and even
Speaker 1: your human way of thinking begins to drift away from you. Suddenly,
Speaker 1: for just a moment, you are aware of the problem
Speaker 1: you overlooked. The more you become a horse, the more
Speaker 1: you forget the original wish. You forget what it was
Speaker 1: like to be a human wondering what it was like
Speaker 1: to be a horse. This moment of lucidity does not
Speaker 1: last long, but it serves as the punishment for your sins.
Speaker 1: A Promethean entrails pecking moment, crouching half horse, half man,
Speaker 1: with the knowledge that you cannot appreciate the destination without
Speaker 1: knowing the starting point. You cannot revel in the simplicity
Speaker 1: unless you remember the alternatives. And that's not the worst
Speaker 1: of your revelation. You realize that the next time you
Speaker 1: reach here with your thick horse brain, you won't have
Speaker 1: the capacity to ask to become a human again.
Speaker 2: You won't understand what a human is.
Speaker 1: Your choice to slide down the intelligent ladder is irreversible,
Speaker 1: and just before you lose your final human faculties, you
Speaker 1: painfully ponder what magnificent extraterrestrial creature, enthralled with the idea
Speaker 1: of finding a simpler life chose in the last round
Speaker 1: to become a human that was dessentive species from my
Speaker 1: book sum and the punchline of the story tells you
Speaker 1: everything you need to know for the context of today's question,
Speaker 1: Can you really know what it's like to be something
Speaker 1: else or someone else? The problem is, the more your
Speaker 1: brain becomes something else, then the less you would be
Speaker 1: able to keep track of the original you who was
Speaker 1: asking the question. So could you modify your brain to
Speaker 1: make it like a cat's brain? When you got there,
Speaker 1: you wouldn't be able to remember what the original question was.
Speaker 1: So let's think about this and extend this. This is
Speaker 1: the same as saying I want to be the actor
Speaker 1: John Malkovich. If you were actually being John Malkovich, you
Speaker 1: wouldn't remember what it was like to be you, wondering
Speaker 1: what it was like to be he. And this is
Speaker 1: the same problem with the movie Strange Days. During playback
Speaker 1: with this helmet, the conceit is that the observer temporarily
Speaker 1: quits his own memories in state of consciousness and takes
Speaker 1: on that of someone else. Okay, so you can't change
Speaker 1: your brain to be exactly someone else's and still retain
Speaker 1: any notion of you.
Speaker 2: But could you have an experience.
Speaker 1: More like VR where you're still you, but you are
Speaker 1: experiencing someone else's senses, like you're.
Speaker 2: Seeing through their eyes. Well sort of.
Speaker 1: But there's a very interesting thing that happens here which
Speaker 1: exposes something very deep about perception. So to understand this,
Speaker 1: we're gonna dive into four movies that try to do this, because,
Speaker 1: as we'll see, this is actually a tougher challenge than
Speaker 1: you might imagine. Okay, so, there was in fact a
Speaker 1: movie called Being John Malkovich. You may have seen it.
Speaker 1: In that movie, there's a struggling puppeteer who discovers a
Speaker 1: hidden door that leads directly into the mind of the
Speaker 1: actor John Malkovich. So for fifteen minutes at a time,
Speaker 1: people can experience the world through Malkovich's eyes until they're
Speaker 1: ejected onto the side of the New Jersey Turnpike.
Speaker 2: Now, how did the.
Speaker 1: Director Spike Jones actually implement this on camera? Well, when
Speaker 1: a character enters the portal, the film switches to a
Speaker 1: first person perspective, literally showing what John Malkovich sees through
Speaker 1: his eyes. Now, to simulate the feeling of inhabiting another
Speaker 1: person's body, what the camera does is mimic the movement
Speaker 1: of the head and it shows us when Malkovich is blinking.
Speaker 1: Essentially the curtain drops because we're on the inside of
Speaker 1: his head and we're seeing those eyelids. And there's also
Speaker 1: a confined feeling of a tunnel. In these shots. The
Speaker 1: edges of the frame are darker, giving the sense that
Speaker 1: you're looking through a peopole or wearing blinkers. Now, this
Speaker 1: is very interesting, right, because that's not actually your experience
Speaker 1: of the world when you're inside your own head. So first,
Speaker 1: what is the reason that you don't see your own blinks?
Speaker 1: Is it because a blink is too fast to notice?
Speaker 1: After all, it only takes eighty milliseconds. Well, no, that's
Speaker 1: not it, because if you are looking out in a
Speaker 1: well lit room and I flick the lights on it
Speaker 1: off for just eighty milliseconds, you have no problem at
Speaker 1: all detecting that. In fact, you can detect something much
Speaker 1: shorter than that. So what's going on why don't you
Speaker 1: see your own blinks? Well, the answer is that you
Speaker 1: have circuitry in your midbrain that sends the motor command
Speaker 1: to blink your eyelids, and it also sends a copy
Speaker 1: of this command to your visual system so that it
Speaker 1: knows a blink is coming. But there's even a deeper
Speaker 1: answer here. The general story, as you have heard me
Speaker 1: talk about in many other episodes, is that you're not
Speaker 1: seeing the world out there. Exactly what you're seeing is
Speaker 1: your internal model of what you believe is out there.
Speaker 1: It's a construction of your brain. Only five percent of
Speaker 1: the input to your visual cortex is coming from the eye.
Speaker 1: All the rest is feedback. It's internally generated activity telling
Speaker 1: you what you expect to see given your entire history
Speaker 1: with the world. And it turns out you don't need
Speaker 1: your eyes at all for vision. You can have full,
Speaker 1: rich visual experience even with your eyes closed. This is
Speaker 1: the experience you have every night when you're dreaming, So
Speaker 1: you only see your internal model of the world. And
Speaker 1: this is why a blink does not disrupt your vision
Speaker 1: because your brain knows it's coming, and so your model
Speaker 1: that I am in this room or I'm walking along
Speaker 1: the sidewalk, that show continues on even though the data
Speaker 1: is interrupted every few seconds. So all this is to
Speaker 1: say that if you were inside someone else's sensory experience,
Speaker 1: you wouldn't see blinks, and also you wouldn't have tunnel vision.
Speaker 2: Why not? After all, your visual field is only.
Speaker 1: About one hundred and twenty degrees across out of the
Speaker 1: three hundred and six degree world. You're only seeing a
Speaker 1: slice of about a third of the vision that's available
Speaker 1: around you. So why do we feel like the world
Speaker 1: doesn't have edges. It's because what you experience is your
Speaker 1: internal model of a full three hundred and sixty degree world.
Speaker 1: And that's because you've looked around and you've filled in
Speaker 1: the picture, sometimes with very low resolution and sometimes just
Speaker 1: with assumption. But in any case, you have a sense
Speaker 1: of a full world around you. So again, if you
Speaker 1: were actually experiencing someone else's vision, it wouldn't look like
Speaker 1: a tunnel. So this is a very difficult problem to
Speaker 1: solve if you are Spike Jones or any movie director
Speaker 1: and you're given this challenge of presenting what it would
Speaker 1: be like to be inside someone else's head experiencing their vision.
Speaker 1: And in fact, something that struck me is that Jones
Speaker 1: put in the blinks and the tunnel vision, but he
Speaker 1: didn't display, for example, the fact that your eyes are
Speaker 1: making large jump three times a second. These are called
Speaker 1: the CODs. Even when you feel like you're just calmly
Speaker 1: observing the world in front of you, your eyes are
Speaker 1: constantly dashing around to find new information. Again, we're not
Speaker 1: aware of this because all we experience is our internal model,
Speaker 1: and our eyes are just seeking new data to put
Speaker 1: into that. By the way, if it doesn't feel like
Speaker 1: your eyes are always dashing around, just get in the
Speaker 1: habit of watching other people's eyes and you'll see that
Speaker 1: they're making large jumps every third of a second.
Speaker 2: So look, I want you to try this.
Speaker 1: Take the video camera on your phone and record the
Speaker 1: scene around you, but jerk the camera around three times
Speaker 1: a second, just like your eyes are doing. Now play
Speaker 1: the video back, and you're gonna see that. It looks terrible.
Speaker 1: It's nauseating to try to watch this. Why because you're
Speaker 1: not experiencing those movements. You're just experiencing your internal model.
Speaker 1: And if your spike Jones and you really really wanted
Speaker 1: to capture the information directly from somebody's eyeballs, you'd have
Speaker 1: to take into account that you only have color vision
Speaker 1: right at the very center of your visual field, because
Speaker 1: that's where you have cones, the color photoreceptors, and your
Speaker 1: retina and everything in your periphery is taken care of
Speaker 1: by rods.
Speaker 2: So that's black and white vision. Most of your.
Speaker 1: Vision is black and white. But you never noticed this.
Speaker 1: You think the whole world is in color simply because
Speaker 1: you are moving your eyes around and your internal model
Speaker 1: is keeping track of everything in color. Again, if you
Speaker 1: don't believe me on this, ask your friend to take
Speaker 1: some colored dry erase markers and hold them in his
Speaker 1: hand and whatever order he wants to put them in. Now,
Speaker 1: stand just a few feet away from him and look
Speaker 1: straight at his nose, and have him hold the markers
Speaker 1: out at his arm's length, but don't look at the markers.
Speaker 1: Stay fixed right on his nose and try to name
Speaker 1: the order of the colors of the markers, and what
Speaker 1: you'll see is that you can't even see the colors.
Speaker 1: If you're actually trying to do a task that involves
Speaker 1: color out in your periphery, you just can't do it
Speaker 1: because there is no color out there. You have to
Speaker 1: move your eyes there to see any color. Okay, So
Speaker 1: let's get back to being John Malkovich. So Spike Jones
Speaker 1: didn't include all these other flourishes about ciccads and black
Speaker 1: and white vision in the periphery, but obviously it wouldn't
Speaker 1: have helped if he did, it would have just made
Speaker 1: it worse, because real vision is nothing like seeing blinks
Speaker 1: and looking down a tunnel and seeing siccads and seeing
Speaker 1: most of the world in black and white. Instead, the
Speaker 1: experience of vision is like being embedded directly in a full, rich,
Speaker 1: colorful world. So this is a tough challenge for a
Speaker 1: movie director to make an attempt to step into someone
Speaker 1: else's head. And it's not just being John Malkovich, but
Speaker 1: lots of movies try this sort of thing, trying to
Speaker 1: show what it's like for you to be inside someone
Speaker 1: else experiencing what it's like to be them. So let's
Speaker 1: return to the movie Strange Days. As I mentioned earlier,
Speaker 1: in that movie, you can record an experience from someone,
Speaker 1: let's say, while they're committing a robbery, and so we'll
Speaker 1: put aside the problem that you can't experience the whole thing,
Speaker 1: the emotions, the thoughts, the feelings. But again, we're just
Speaker 1: going to ask what the movie director did to make
Speaker 1: us feel like we were inside the visual system of another.
Speaker 1: So when the director needed to show us this, he
Speaker 1: showed us from a first person point of view, because
Speaker 1: after all, that's what was being sold in the helmet.
Speaker 1: And what we saw was the camera bouncing up and down,
Speaker 1: indicating that the first person point of view we were
Speaker 1: in was running on foot from the cops. Now, that
Speaker 1: cracked me up because it represents a basic error of
Speaker 1: what it's really like to be running. When you are running,
Speaker 1: your visible world does not bounce up and down. Your
Speaker 1: visual system takes account of the movement of your muscles
Speaker 1: and it compensates for that. As a result, your view
Speaker 1: of the outside world is steady. And this is because
Speaker 1: your conscious view is a notion of the world outside
Speaker 1: of you. Your visual system isn't simply there to register
Speaker 1: the data coming in. Whatever hits your eyes is simply
Speaker 1: contributing to the model of a stable outside world. And
Speaker 1: as I said, a lot of this has to do
Speaker 1: with your body making predictions about how the world will
Speaker 1: change when it moves. Just as one quick example of this,
Speaker 1: do you think it would have helped if the director
Speaker 1: in Strange Days had the protagonist's hands reaching in in
Speaker 1: front of the camera. Would this look more realistic as
Speaker 1: though your own hands were coming into your field of view.
Speaker 1: That would have made things even worse, even less convincing,
Speaker 1: because although we do see our own hands reaching from
Speaker 1: below our visual fields, we are the ones controlling them,
Speaker 1: and that makes all the difference. We can predict exactly
Speaker 1: where they are and when they'll appear, because the regions
Speaker 1: of your brain that sends commands out to your body
Speaker 1: also sends copies of those commands all around to the
Speaker 1: rest of your brain, so that your visual system, for example,
Speaker 1: knows what's coming. If you want to read more about this,
Speaker 1: this is what's known as the motor efherence copy. Let
Speaker 1: me give you a good example of this point. So
Speaker 1: let's look at the movie Hatchi. This movie is about
Speaker 1: a college professor Richard Gere, who finds an abandoned puppy
Speaker 1: at a train station and takes them home, and they
Speaker 1: form a very close bond. And every day Hotchi waits
Speaker 1: at the train station for the Professor to return from work.
Speaker 1: But then the Professor dies unexpectedly, but Hotchie continues to
Speaker 1: return to the train station every day, waiting faithfully for
Speaker 1: nearly a decade, unaware that his owner is gone. It's
Speaker 1: a total tear jerker. Now here's the thing. The director
Speaker 1: wanted to show some of the shots from the dog's
Speaker 1: point of view, so here's how he went about this.
Speaker 2: First, he films the dog lying on.
Speaker 1: The grass with legs stretched in front and chin on
Speaker 1: the ground, watching the professor clipping the rose bushes, and
Speaker 1: suddenly we cut to the dog's point of view. We
Speaker 1: see the professor from a very low angle and in
Speaker 1: black and white. Okay, fine, but to drive this point home,
Speaker 1: we are then back outside the dog and we see
Speaker 1: the dog roll over sideways onto the grass, and then
Speaker 1: the director cuts to the internal dog camera and we
Speaker 1: see the horizon rotate to vertical, and then we're back
Speaker 1: outside the dog and we see the dog roll over
Speaker 1: until his paws are sticking up in the air and
Speaker 1: his head is upside down. And now the camera jumps
Speaker 1: back into the dog and shows us the world of
Speaker 1: the garden flipped.
Speaker 2: One hundred and eighty degrees.
Speaker 1: Now, this seems like a clever way to use the
Speaker 1: camera to personalize the dog's experience.
Speaker 2: Right wrong.
Speaker 1: There's an interesting rookie error of perception here. When your
Speaker 1: head turns sideways, the world doesn't turn sideways. Try it.
Speaker 1: Try it turning your head the world remains stable, and
Speaker 1: your internal model remains stable because you have a sense
Speaker 1: of where gravity is. So seeing the world through someone's eyes,
Speaker 1: whether John Malkovich or with the Strange Day's Helmet or
Speaker 1: with Hatchie the Dog, it's not so straightforward to show.
Speaker 1: And sometimes the difficulty is even more subtle than that.
Speaker 1: For our fourth movie, take The Terminator played by Arnold Schwarzenegger,
Speaker 1: where he's this killing machine from the future. So how
Speaker 1: does the director try to show us the experience of
Speaker 1: the robot. Well, occasionally the camera switches to the robots
Speaker 1: first person point of view, and what does that look like? Well,
Speaker 1: the shot shows the familiar cinematic landscape, whether he's in
Speaker 1: a hallway or a city street or whatever. But it's
Speaker 1: overlaid now with flickering data. You've got these red gridlines
Speaker 1: and numbers scrolling past, and words pop up and flickers
Speaker 1: of infrared and occasional diagnostic information. So this is meant
Speaker 1: to communicate to us. Now you're seeing what the terminator sees.
Speaker 1: But there's a funny paradox here because what we're really
Speaker 1: being shown isn't a first person experience at all. It's
Speaker 1: like the robot has a little film crew living inside
Speaker 1: his head, filming the world through his eyes and then
Speaker 1: adding the heads up display. But that's not how brains
Speaker 1: or machines work. As we've been talking about, well, to
Speaker 1: be inside of you is not the same as peering
Speaker 1: out of your eyes like a camera. Consciousness is our
Speaker 1: experience of being in the world. So in this case,
Speaker 1: if your consciousness showed numbers, who's watching those numbers? What
Speaker 1: this actually suggests is that there's a little Schwarzenegger sitting
Speaker 1: at the back of his head watching and reading these numbers.
Speaker 1: In other words, you don't have a screen inside your mind,
Speaker 1: even for a robot, even if it were conscious, you
Speaker 1: wouldn't experience an image with data superimposed. Information is encoded
Speaker 1: and interpreted in processed, but there's no need to visually
Speaker 1: represent numbers for itself to read.
Speaker 2: Think about it this way. Your brain doesn't.
Speaker 1: Need to overlay subtitles when you recognize somebody's face. Imagine
Speaker 1: there were words that read you are now looking at
Speaker 1: the face of Susiq, and then you had to read
Speaker 1: those words and then you understand that you're looking at
Speaker 1: her face. That's not how it works.
Speaker 2: You just have a direct experience.
Speaker 1: There's nobody else for whom you would need to display
Speaker 1: the words. So when filmmakers try to show us what
Speaker 1: it is like to be someone or something else, what
Speaker 1: they're really doing is showing us what they think it
Speaker 1: might be to look out from behind someone's eyes. But
Speaker 1: consciousness is not like that. You don't see blinks, you
Speaker 1: don't see a tunnel, you don't see the world bouncing
Speaker 1: when you run, you don't see the world turn sideways
Speaker 1: when you turn sideways, and you don't see words displayed
Speaker 1: in your mind just for you to read and then
Speaker 1: understand them. So what does this tell us? It reminds
Speaker 1: us that conscious experience isn't about what your eyeballs are doing,
Speaker 1: but instead what you're experiencing as your internal model. And
Speaker 1: that's why, as clever as these movies are, they can
Speaker 1: never really show us what it's like to be someone
Speaker 1: else from the inside. At best, they give us a
Speaker 1: visual metaphor, but that kind of metaphor is not even
Speaker 1: close to actual experience. So what we're seeing is that
Speaker 1: the plot of Strange Days, where you live someone else's
Speaker 1: experience and the way that they experienced it, is presumably impossible.
Speaker 1: So to pull this all together, let's return to the
Speaker 1: idea of dream celebrities, this idea of recording your dreams
Speaker 1: and playing them to someone else and becoming a social
Speaker 1: media star of the nocturnal world. So let's make sure
Speaker 1: this is clear. You could imagine just getting the visuals
Speaker 1: of what someone else saw, but there are a couple
Speaker 1: of things to note here. If I just measured the
Speaker 1: activity in your visual cortex while you dreamed, and then
Speaker 1: I fed that same data into stimulation of my visual cortex,
Speaker 1: it wouldn't be exactly the same because even in the
Speaker 1: primary visual cortex there are individual differences, So what I
Speaker 1: saw would be a warped version of what you saw. Okay,
Speaker 1: no problem. Some day in the future we could morph
Speaker 1: from your visual cortex to my visual cortex and warp
Speaker 1: the show appropriately. But the deeper problem is your experience
Speaker 1: would just be like a VR visual experience, which is
Speaker 1: different than you sharing your thoughts and emotions. For example,
Speaker 1: let's say a particular face comes into your dream. I'd
Speaker 1: see that face, but I wouldn't have any idea that
Speaker 1: to you, to face strikes terror, or maybe the face
Speaker 1: is someone you have a deep crush on, whereas I
Speaker 1: don't know who it is. To me, it's just the
Speaker 1: visual of two eyes and a nose and a mouth.
Speaker 1: That's the difference between a purely visual facsimile on my
Speaker 1: visual cortex and my brain becoming your brain and.
Speaker 2: Experiencing what you experience.
Speaker 1: So let's even imagine that you said, fine, let's figure
Speaker 1: out all the rest of the circuitry and we warp
Speaker 1: it so that you can have exactly what I have.
Speaker 1: But this is just a bigger issue of what I
Speaker 1: mentioned about the visual cortex. The detailed, three dimensional microstructure
Speaker 1: of your brain is unique to you. That's why you
Speaker 1: have your own thoughts and see the world your own way.
Speaker 1: This is the major challenge of transferring thoughts from one
Speaker 1: mind to another. I mentioned in an episode a while
Speaker 1: ago this scene from the Matrix where Trinity says, tank,
Speaker 1: I need a program for a B two twelve helicopter
Speaker 1: and he the operator, finds one and loads one, and
Speaker 1: the knowledge is immediately present in her head. But the
Speaker 1: problem is that Trinity's new knowledge rests in a network
Speaker 1: of her old experiences. For example, pulling on the helicopter
Speaker 1: stick is similar or to pulling on horses reins. And
Speaker 1: the only way to get at this and put that
Speaker 1: new knowledge in is if you knew every detail of
Speaker 1: Trinity's brain. But again, that's not even the deepest problem.
Speaker 1: The deepest problem is whether you could ever be two
Speaker 1: people at once. If you were able to figure out
Speaker 1: the mapping from your brain to someone else's brain so
Speaker 1: that you could somehow download his dream state into your head,
Speaker 1: you wouldn't be you anymore experiencing his dream You would
Speaker 1: be someone else with no knowledge of you. And what's
Speaker 1: the point of that? Okay, so what we talked about
Speaker 1: so far is the possibility that becoming someone else is
Speaker 1: going to be impossible.
Speaker 2: But could you nonetheless get.
Speaker 1: Closer by adding new inputs to the brain. Way back
Speaker 1: in episode twelve, I talked about the technology that we
Speaker 1: built in my lab, for example, a vest covered and
Speaker 1: vibratory motors that can put specific patterns onto your torso
Speaker 1: and you can feed in new data streams to the
Speaker 1: brain that way. Could this give you some little window
Speaker 1: into someone else's experience. So as one example, we shrunk
Speaker 1: this vest down to a wristband, and then we had
Speaker 1: people wear the wristband on one hand and a smart
Speaker 1: watch on the other, and the smart watch tracks all
Speaker 1: kinds of things about their physiology, like their heart rate
Speaker 1: and heart rate variability and galvanic skin response. And we
Speaker 1: had that data stream from the watch over the Internet
Speaker 1: and into the wristband. So you are feeling a summarized
Speaker 1: version of your physiological signals that are normally invisible. But
Speaker 1: that's not the really interesting part. The really interesting part
Speaker 1: was that we now put the wristband on someone else.
Speaker 1: Say you're a romantic partner, and now he or she
Speaker 1: can be across the country, but can be constantly feeling
Speaker 1: your physiology and know when you're stressed and when your
Speaker 1: heart rate is going up and your galvanic skin response
Speaker 1: is rising. Now, I'm not totally clear whether this would
Speaker 1: be good or bad for couples. But it is a
Speaker 1: way of opening up a small channel into the experience
Speaker 1: of someone else. And I think there are many ways
Speaker 1: that adding new senses could bring you closer to someone
Speaker 1: else's experience. For example, someone who is born blind is
Speaker 1: not able to understand what vision is. If you have
Speaker 1: a friend who's born blind and you say, yeah, I'm
Speaker 1: capturing photons from half a mile away, and I can
Speaker 1: perceive what's out there, and the person walking towards me
Speaker 1: from a distance, your friend.
Speaker 2: Has no way of understanding that. Because they're your friend.
Speaker 1: They might pretend that they sort of get it, but
Speaker 1: they can't because they've never had the experience of this
Speaker 1: super spy technology of capturing distant photons. So if you
Speaker 1: took someone like Helen Keller who was born deaf and blind,
Speaker 1: and you fed in the auditory and visual data, let's
Speaker 1: say through a vest or wristband, so she could tap
Speaker 1: into those experiences, I do think that would get her
Speaker 1: slightly closer to understanding what it is like to be
Speaker 1: a hearing and cited person. So I think as we
Speaker 1: get better at figuring out how to add senses directly
Speaker 1: to the brain, we can at least get closer to
Speaker 1: understanding the sensory experiences that other people may have. And
Speaker 1: I'll just mention that in an earlier episode, I've also
Speaker 1: talked about how flexible the brain is in terms of
Speaker 1: adding new interfaces for moving, like robotic arms that you
Speaker 1: could control with your brain. The only point I want
Speaker 1: to make today is that by coming to have a
Speaker 1: different body, like let's say you're able to control a
Speaker 1: robotic trunk, you might be able to get closer to
Speaker 1: understanding what it is like to be another creature, like
Speaker 1: an elephant. Okay, so let's wrap up. We set out
Speaker 1: today chasing a timeless question. Can we ever truly know
Speaker 1: what it is like to be someone else? Not just
Speaker 1: to guess or to empathize or imagine, but to be
Speaker 1: in their skin, to see through their eyes, to feel
Speaker 1: with their nervous system. Technology peases us with this dream,
Speaker 1: from the mind recording helmets of strange days to the
Speaker 1: dream sharing fantasies of tomorrow's celebrity subconscious. But the closer
Speaker 1: we approach the boundaries of another mind, the more we
Speaker 1: find the self slipping through our fingers. To become someone
Speaker 1: else is to lose the very self who wants to
Speaker 1: know that, and we saw that consciousness is not a
Speaker 1: camera looking out, but a story being told from the inside,
Speaker 1: a model stitched together from prediction and memory and bodily anchoring.
Speaker 1: And that story can't be exported wholesale. It's inseparable from
Speaker 1: the teller. Now, movies try to do this. Directors try
Speaker 1: to jump into other heads with first person shots and
Speaker 1: tilted frames and blinking eyelids and bouncing camera rigs. But
Speaker 1: even the cleverest cinematography can't breach the firewall of subjectivity.
Speaker 1: You can mimic a viewpoint, but not the viewing. You
Speaker 1: can borrow the eyes, but not the mind behind them.
Speaker 1: And so every attempt to simulate another's experience is like
Speaker 1: trying to paint a dream with a camera. The image
Speaker 1: may flicker with familiarity, but the feeling remains out of reach. Okay,
Speaker 1: but still, when we're trying to understand someone else, we
Speaker 1: can build bridges. Maybe they're not full crossings, but they're footpaths.
Speaker 1: With wearable technology or shared biofeedback or sensory augmentation, we
Speaker 1: can inch closer, not to being one another, but to
Speaker 1: understanding one another a little more richly, And.
Speaker 2: Perhaps that's enough.
Speaker 1: Perhaps the future is not about dissolving the boundaries between selves,
Speaker 1: but about illuminating those boundaries, tracing their contours with data
Speaker 1: and compassion and curiosity.
Speaker 2: We may never fully be each other, but we.
Speaker 1: Might, with the right tools and intentions, meet more meaningfully
Speaker 1: at the borders. Go to eagleman dot com slash podcast
Speaker 1: more information and to find further reading. Find me on
Speaker 1: substack or send me an email at podcasts at eagleman
Speaker 1: dot com with questions or discussion, and check out and
Speaker 1: subscribe to Inner Cosmos on YouTube for videos of each
Speaker 1: episode and to leave comments Until next time. I'm David Eagleman,
Speaker 1: and this is Inner Cosmos.