Speaker 1: From the brain's point of view, What is the self?
Speaker 1: How do you put together thirty six trillion cells and
Speaker 1: have it feel like one thing? Does the self of
Speaker 1: a blind person include the tip of the walking stick?
Speaker 1: How flexible is our sense of self? And what does
Speaker 1: any of this have to do with psychedelics or trauma,
Speaker 1: or synchronized swimmers, or religious rituals or cheerleaders, or why
Speaker 1: soldiers across time and place love to march in unison
Speaker 1: in lockstep. Welcome to Inner Cosmos with me David Eagleman.
Speaker 1: I'm a neuroscientist and an author at Stanford and I've
Speaker 1: spent my career at the intersection between how the brain
Speaker 1: works and how we experience life. So I'm going to
Speaker 1: beget in today's episode with a question that I've wondered
Speaker 1: about since i was a kid. Something I've always found
Speaker 1: amazing is watching armies, thousands of soldiers march in perfect lockstep.
Speaker 1: And even as a kid, I noticed that across the world,
Speaker 1: all armies did this and this goes back to the
Speaker 1: earliest days of armies. And I know this because when
Speaker 1: I was younger, I read about how the Romans discovered
Speaker 1: a problem where if they marched in lockstep over a bridge.
Speaker 1: It would sometimes hit the resonance frequency of the bridge
Speaker 1: and then it would collapse. So they learned from their mistakes,
Speaker 1: and whenever they came to a bridge, they would purposely
Speaker 1: go out of sync with one another and they would
Speaker 1: cross the bridge that way. But the point is that
Speaker 1: they normally marched in lockstep. They, like all modern armies,
Speaker 1: loved acting as a mega organism. So why do armies
Speaker 1: love to synchronize? I mean, why not just have all
Speaker 1: the soldiers walk asynchronously however they want to, as long
Speaker 1: as they keep up well. One hypothesis would be that
Speaker 1: an army marching in lockstep is intimidating. You see something
Speaker 1: coming at you. That's like a giant, unified, single minded monster.
Speaker 1: And a related hypothesis could be that an army stepping
Speaker 1: with precision timing represents discipline and training, the way we
Speaker 1: watch dancers or synchronized swimmers, and across sports like ballet
Speaker 1: or cheerleader or whatever, athletes pursue this kind of perfect synchronization.
Speaker 1: In other words, the army does it not just because
Speaker 1: it's scary, but also because it represents discipline and training
Speaker 1: to get there. And these both seem like reasonable hypotheses.
Speaker 1: But I have something else to segest today, something that
Speaker 1: I think you might find quite surprising and hopefully enlightening
Speaker 1: because of all the other things that it sheds light on.
Speaker 1: So what seems like an arbitrary question can sometimes unearth
Speaker 1: a lot. But first, let's start at the beginning. So
Speaker 1: let's step back to sixteen thirty seven, when Renee de
Speaker 1: Kartes famously wrote Japan's don't suis I think? Therefore I am?
Speaker 1: Now when he says I, we all understand what he
Speaker 1: means here, we think, but what exactly is the I
Speaker 1: If you think it's obvious what the self is, get
Speaker 1: ready for some eye openers, because we're going to see
Speaker 1: how the self emerges from computations in the brain and
Speaker 1: how it can morph in unexpected ways. So let's start
Speaker 1: by noting that nothing seems more obvious than you feel
Speaker 1: like a single entity. But that's strange because you're actually
Speaker 1: built out of thirty six trillion individual cells communicating through
Speaker 1: chemical and electrical signals. But you don't feel like that.
Speaker 1: You don't feel like a swirling bath of seven billion,
Speaker 1: billion billion atoms, not to mention that you're constantly shedding
Speaker 1: atoms and gaining new ones, such that your body is
Speaker 1: composed of entirely new atoms about every seven years. Despite
Speaker 1: all this, you feel like one stable thing. You feel
Speaker 1: like you. You have a name, You have a history
Speaker 1: and a memory, and a personality. You have desires, and
Speaker 1: you are unique personality. You have a self, and that
Speaker 1: self seems to be located right behind your eyeballs. Now
Speaker 1: this is wild, right, because consider other scenarios in which
Speaker 1: there are lots of pieces and parts working together. Let's
Speaker 1: say I go out to some big field and I
Speaker 1: set up a bunch of and pulleys and levers, and
Speaker 1: I start hooking everything up and this turns that, and
Speaker 1: that affects that, and this lever pulls that thing, and
Speaker 1: I start adding more and more parts in this big
Speaker 1: crazy machine gets larger and larger. Here's the question, At
Speaker 1: what point do I add one more lever and I say, ah,
Speaker 1: Now this is no longer a Frankensteinian collection of trillions
Speaker 1: of individual pieces, but suddenly it has the experience of
Speaker 1: a living unity. Or just take your computer. It's made
Speaker 1: of billions of transistors and resistors and capacitors. It's sending
Speaker 1: zeros and ones all around. But the question is does
Speaker 1: your MacBook pro have a sense of itself? Do you
Speaker 1: think it ever aspires to be something greater in its life?
Speaker 1: Or does it feel a sense of embarrassment and its
Speaker 1: performance sometimes, or does it ever desire to be loved
Speaker 1: by another computer? Now, the reason your sense of self
Speaker 1: is so mysterious is because your brain is just made
Speaker 1: up of pieces and parts cells with straightforward properties, each
Speaker 1: cell by itself as just doing basic sell things. So
Speaker 1: why does this giant collection, when hooked up and interacting
Speaker 1: in the right way, have a unified sense of a
Speaker 1: single you interacting with the world through time. You have
Speaker 1: this conscious perception of yourself as a thing such that
Speaker 1: the thirty six trillion cells that comprise you can collaborate
Speaker 1: to go to a dance club tonight, or meet friends
Speaker 1: at the coffee shop, or go to a bookstore, or
Speaker 1: take a road trip across the nation, acting like a
Speaker 1: single thing. So why do you feel like a unified entity? Now?
Speaker 1: The answer, presumably is an evolutionary one. Those cells are
Speaker 1: all hanging together, and this collection has to take the
Speaker 1: whole vast complet space of possibilities and crunch it down
Speaker 1: to a single decision. For example, your body can go
Speaker 1: to the left or go to the right to get
Speaker 1: around the tree, but you can't do both, and that's
Speaker 1: why you have to squeeze down all the chattering of
Speaker 1: billions of neurons to a single choice and control your
Speaker 1: trillions of cells to do something that makes sense in
Speaker 1: the outside world. I've mentioned before that the brain is
Speaker 1: typically celebrated for its parallel processing, but in fact, just
Speaker 1: as importantly it should be celebrated for its serialization. In
Speaker 1: other words, its ability to conclude something, to decide something
Speaker 1: from the vast space of possibilities, to take all the
Speaker 1: rumbling trillions of cells and get to a single conclusion
Speaker 1: about what to do next. So that's presumably why you
Speaker 1: have a unified sense. But the story gets stranger from
Speaker 1: here because the sense of self is not fixed, it's
Speaker 1: not nailed into place. Instead, it's quite fluid, and in
Speaker 1: many scenarios what we find is a dissolution of the self.
Speaker 1: For example, various drugs can have profound effects on an
Speaker 1: individual's sense of self. They lead to an alteration of
Speaker 1: one's identity. And this is amazing, right, because these are
Speaker 1: invisibly small molecules with particular shapes, and when they enter
Speaker 1: your system and bind to particular receptors in your brain
Speaker 1: and change the activity just a little bit, then this
Speaker 1: neural technology that builds selfness breaks down. For example, a
Speaker 1: lot of psychedelic drugs do this. They bind to particular
Speaker 1: receptors here and there, and they cause profound alterations in
Speaker 1: the feeling of self. Think of LSD or SILAS or DMT.
Speaker 1: What happens when people take this is they report a
Speaker 1: dissolving of their ego boundaries, leading to experiences of what's
Speaker 1: sometimes called an ego death, meaning the loss of self identity.
Speaker 1: You also have substances like ketamine or PCP or some
Speaker 1: synthetic cannabinoids, and these can trigger feelings of depersonalization and dissociation.
Speaker 1: In other words, people on these drugs get a sense
Speaker 1: of detachment from their own body, or their emotions or
Speaker 1: their surroundings, so they have a distorted perception of self.
Speaker 1: And you sometimes see this with certain psychiatric medications when
Speaker 1: they're misused or taken in appropriately. They can alter cognition
Speaker 1: and emotion and often lead to a feeling of disconnection
Speaker 1: from a person's identity or sense of self, and all
Speaker 1: throughout the drug world, you find people mixing different drugs
Speaker 1: together and getting all kinds of severe things like dissociation
Speaker 1: and confusion and a loss of coherent self awareness. So
Speaker 1: what does this tell us? In all these situations, we
Speaker 1: see how invisibly small molecules can disrupt the normal, very
Speaker 1: delicate functioning of the brain, and that busts up the
Speaker 1: computation of the self. And you can find the same
Speaker 1: thing not just from the influence of molecules, but also
Speaker 1: from the influence of experiences. Just look at something like
Speaker 1: post traumatic stress disorder. Beyond the emotional challenges that we
Speaker 1: find there, we also find cognitive impacts like a pervasive
Speaker 1: sense of disconnection from one's identity and a loss of
Speaker 1: coherence in self perception. For example, sometimes people report feeling
Speaker 1: like an object rather than a person. Now, what happens
Speaker 1: when we measure the effects of post traumatic stress disorder
Speaker 1: in the brain. While there's a network called the default
Speaker 1: mode network, and this network is critical for constructing one
Speaker 1: sense of self, and in post traumatic stress disorder, for example,
Speaker 1: you can find in neuroimaging that the connectivity gets disrupted,
Speaker 1: and this appears to correlate with problems with one's perceived
Speaker 1: sense of self. This feeling that people sometimes have in
Speaker 1: post traumatic stress disorder, where they say they don't know
Speaker 1: who they are, where they feel like they've stopped existing.
Speaker 1: What this reflects is a disruption in their networks that
Speaker 1: are critical to computing the self, and we see disruptions
Speaker 1: of the self in closely related clinical settings also, for example,
Speaker 1: in dissociative identity disorder. This is where people usually who
Speaker 1: have been through some trauma, will have a fragment of
Speaker 1: their self into different identities. They switch personalities. They can
Speaker 1: have these sudden changes in mood and in their behavior,
Speaker 1: and family members can usually tell when a person switches
Speaker 1: their personality. And by the way, they often get amnesia.
Speaker 1: They can't remember what they said just a few minutes
Speaker 1: ago when they were speaking as one of their other personalities.
Speaker 1: I'll just note that often people with dissociative identity disorder
Speaker 1: are misdiagnosed as having schizophrenia because their beliefs are interpreted
Speaker 1: as a delusion. But I think more properly this could
Speaker 1: be interpreted as yet another demonstration that the brain has
Speaker 1: to go through an enormous amount of very delicate work
Speaker 1: to construct the self, and there are lots of ways
Speaker 1: this can be disrupted. Now, how can we study this?
Speaker 1: In the lab, one of my colleagues at Stanford, Joseph Parvizi,
Speaker 1: was studying patients with epilep see people who have electrical
Speaker 1: seizures in the brain. So one day one of his
Speaker 1: patients with APLEPSI tells him every time I have a seizure,
Speaker 1: I have a sense of depersonalization and dissociation. Everything's unreal,
Speaker 1: It's like it's not happening to me. And Parvez finds
Speaker 1: out that this patient's seizures started in a tiny brain
Speaker 1: area right in the brain's midline, called the anterior precuneus.
Speaker 1: And there was something very interesting about this area because
Speaker 1: it's not part of the default mode network, which I
Speaker 1: mentioned a moment ago, but instead it's a node at
Speaker 1: the center of a different network consisting of different areas.
Speaker 1: And this network integrates data about where you are and
Speaker 1: how you're moving, and where your muscles and joints are,
Speaker 1: so it's involved in building a mental map of your
Speaker 1: physical self. Now, just before I tell you more about this,
Speaker 1: one of the things I think is interesting is how
Speaker 1: parvs this ditinguishes between the I and the me. He says, Look,
Speaker 1: for every action we take, even during dreams, there's always
Speaker 1: an agent behind it. We call that agent I. But
Speaker 1: me is everything we have stored in our memories about
Speaker 1: the I. In other words, the eye has to do
Speaker 1: with your sense of your body in the immediate here
Speaker 1: and now, with a particular point of view, a first
Speaker 1: person perspective that belongs to only you. But the me,
Speaker 1: that's the narrative self, that has to do with actively
Speaker 1: or passively thinking about your past life or planning your future,
Speaker 1: things like memory and habits and personality, emotions, feelings for others,
Speaker 1: what lies ahead, and so on. Okay, now here's the
Speaker 1: key point from the brain's point of view. These two
Speaker 1: functions of the eye and the me, they're actually underpinned
Speaker 1: by separate networks of brain areas. These networks interact, they're
Speaker 1: not the same. So the me involving my memory, inhabits
Speaker 1: and personality and emotions, that mostly involves the default mode network.
Speaker 1: But the eye, which gives my sense of my particular
Speaker 1: point of view right now, that involves this other network
Speaker 1: where the anterior precunius sits at the center. And what
Speaker 1: Parvizi found is when that network becomes disrupted, let's say
Speaker 1: by an epileptic seizure that disrupts your self in the
Speaker 1: here and now. So he stuck electrodes into the anterior
Speaker 1: precuneus and zaps with electricity, and people say that something
Speaker 1: weird happens to their sense of physical self. They get
Speaker 1: a depersonalization, similar to what happens with psychedelics. It's not
Speaker 1: an out of body experience. People still feel like they're
Speaker 1: in their bodies, but they generally feel like there's a
Speaker 1: change in their orientation or their location, depending on where
Speaker 1: the stimulation happens. They feel like they're floating, your sinking,
Speaker 1: and it doesn't make any sense when they look around
Speaker 1: and they see where they are. And so their report
Speaker 1: was that the world around them seemed unreal. So again
Speaker 1: I want to be clear that you require this extraordinarily specific,
Speaker 1: delicate operation of multiple networks in the brain to make
Speaker 1: you feel a particular way, to give you an eye
Speaker 1: that's anchored in space with a point of view, and
Speaker 1: a me with a stable sense of who you are,
Speaker 1: and a connection to your memories and your sense as
Speaker 1: an individual. Now, assuming you have average good luck, then
Speaker 1: you'll never even be conscious of this perspective on the world.
Speaker 1: But if your brain gets disrupted from drugs or trauma
Speaker 1: or epilepsy, you're suddenly going to see it. Your world
Speaker 1: will seem unreal, and you'll come to understand that the
Speaker 1: self is a construction of the brain and needs all
Speaker 1: the pieces and parts to be running just right. Okay,
Speaker 1: so what we've talked about so far is the way
Speaker 1: the self can get disrupted. But now I want to
Speaker 1: switch gears to a less studied area. Instead of the
Speaker 1: dissolution of the self, I want to consider the expansion
Speaker 1: of the self. Now. I started thinking about this many
Speaker 1: years ago, even when I was a kid. I noticed
Speaker 1: that when you ride a bicycle, and maybe you accidentally,
Speaker 1: without meaning to, you run over a little worm that's
Speaker 1: crawled onto the sidewalk, and you recoil as though you'd
Speaker 1: physically stepped on the worm yourself with your bare feet,
Speaker 1: even though it was only the bicycle that touched the worm.
Speaker 1: So I started wondering if the bicycle becomes essentially a
Speaker 1: part of you, an extension of the self of some sort.
Speaker 1: And then when I got to college, I ended up
Speaker 1: reading some philosophers like Maurice Merleau Ponti and Gregory Bateson
Speaker 1: who posed a question like this about a blind man
Speaker 1: with a stick. The question was where does the blind
Speaker 1: man's self end and the rest of the world begin.
Speaker 1: You can think of the stick as like an extended
Speaker 1: cognitive system that pulls in information from the world. So
Speaker 1: does the blind man end at the handle of the
Speaker 1: stick or at the tip of the stick? Or does
Speaker 1: his self end somewhere in between? As Merleau Ponti wrote, quote,
Speaker 1: the blind man's cane has ceased to be an object
Speaker 1: for him. It's no longer perceived for itself. Rather, the
Speaker 1: caine's furthest point is transformed into a sensitive zone end quote.
Speaker 1: In other words, since the world is a deserved through
Speaker 1: the stick, it becomes part of the man's self. So
Speaker 1: humans alter the borders of their self all the time
Speaker 1: by using new instruments. I talked way back in episode
Speaker 1: two about dogs who learn how to ride skateboards, and
Speaker 1: even though wheels are not a part of the evolutionary
Speaker 1: history of canines, it becomes part of the dog. They
Speaker 1: become one with the skateboard, and I talked about surfing
Speaker 1: dogs even though the dog skeleton didn't evolve to be
Speaker 1: big and long and flat. The dog has no trouble
Speaker 1: incorporating the surfboard into its body plan into itsself. So
Speaker 1: we're not limited by the borders of our skin, but
Speaker 1: instead these self can expand. And I've also previously mentioned
Speaker 1: some experiments that were done years ago where a monkey
Speaker 1: learns to use a little rake to get some food
Speaker 1: that he couldn't otherwise reach. And once the monkey becomes
Speaker 1: proficient at this, there are cells in its brains sells
Speaker 1: that command actions and sells that sense what's going on.
Speaker 1: These cells change to include the rake in the space
Speaker 1: that they care about, what's known as their receptive field.
Speaker 1: In other words, the rake literally becomes part of the monkey.
Speaker 1: So whether we're talking about bicycle tires or walking canes
Speaker 1: for the blind, or the monkey and the rake, we
Speaker 1: see that the notion of the self has flexibility. It's
Speaker 1: not something that's just genetically pre programmed and fixed into place.
Speaker 1: So how does the body decide what to include what
Speaker 1: makes up the self? Well, in my last book, Live Wired,
Speaker 1: I proposed an answer to this. In part, it's about control.
Speaker 1: If the brain can control something, it becomes part of
Speaker 1: the self. So, for example, when my brain sends out
Speaker 1: signals to move my arm. My arm follows the commands,
Speaker 1: and therefore it becomes part of my self. The monkey's
Speaker 1: rake becomes part of what it can use and command
Speaker 1: in the world, so it becomes in a sense, part
Speaker 1: of its body. Now. Fundamentally, remember the brain is locked
Speaker 1: in silence and darkness, and so what does command mean
Speaker 1: to it? Fundamentally, it's all about prediction. Now. In an
Speaker 1: earlier episode forty four, we dove into the issue about
Speaker 1: the brain being a prediction machine. That's all it's trying
Speaker 1: to do. Locked in silence and darkness, It's trying to
Speaker 1: figure out what's happening in the world out there, And
Speaker 1: for really sophisticated brains like ours, it's not just about
Speaker 1: reacting to what happened, but instead having a model of
Speaker 1: the world that makes predictions about what will happen. So
Speaker 1: given this, what else can become a part of the cell.
Speaker 1: We are used to our brains controlling just our limbs,
Speaker 1: and this is because evolution has built us with muscle
Speaker 1: and tendons and nerves. But evolution never came up with
Speaker 1: controlling distant limbs via bluetooth. So in theory, if you
Speaker 1: could control a robotic arm with your brain, or a
Speaker 1: metal avatar that's all the way across town. This would
Speaker 1: become part of your self. And one question is what
Speaker 1: consequence would this have for your conscious experience. The answer
Speaker 1: is that the robot or the avatar would be perceived
Speaker 1: as a part of you. It would be another limb.
Speaker 1: It would be an unusual limb because of the physical
Speaker 1: gap between you and it, but it would nonetheless qualify
Speaker 1: as an extension of you. Think of the Avatar movies.
Speaker 1: The protagonist Jake Sully thinks of something he wants to
Speaker 1: do with his limited body, and the eight foot all
Speaker 1: avatar moves accordingly, and therefore the avatar becomes an extension
Speaker 1: of his self. By the way, you see this all
Speaker 1: the time. In the military. A soldier is in charge
Speaker 1: of driving a bomb sniffing robot, and everything the soldier
Speaker 1: commands with his joystick, the robot does. And at some point,
Speaker 1: if the robot gets blown up, it's not unusual to
Speaker 1: see one of these soldiers crying and heartbroken. It's like
Speaker 1: a part of them physically has been lost. Now, if
Speaker 1: this kind of extension of the self seems strange, just
Speaker 1: remember that you have everyday experience with this. Whenever you
Speaker 1: look in a mirror and move your body around, you
Speaker 1: see a distant object move in perfect synchrony with your
Speaker 1: motor commands. Your brain says, lift your arm, and you
Speaker 1: see this thing across the room, lift its arm. It's
Speaker 1: a perfect prediction. And so when you do that, you
Speaker 1: understand the reflection as your self. You don't feel any
Speaker 1: direct sensation from the distant limbs, but your brain registers
Speaker 1: the prediction. Every time I send out a command for X,
Speaker 1: that body over there does X, and that's enough for
Speaker 1: your reflection to become a member of the selfhood tribe.
Speaker 1: And one of the things I've written about recently is
Speaker 1: expanding oneself using virtual reality. You're in a virtual world
Speaker 1: and you raise your arm and you see your virtual
Speaker 1: avatar and the virtual mirror raise its arm. You tilt
Speaker 1: your head and it tilts its head. Now, interestingly, people
Speaker 1: are studying this in the context of empathy, because you
Speaker 1: can put someone else's face on the virtual avatar. Let's
Speaker 1: say someone of a different gender and a different race,
Speaker 1: and the question is how do you feel after having
Speaker 1: them be a part of you for a while. And
Speaker 1: you can experiment with very different kinds of bodies in VR.
Speaker 1: What if in a VR world you're one hundred feet tall,
Speaker 1: or you have eight legs or three arms. In all
Speaker 1: of these cases, you can learn to control that body,
Speaker 1: to predict what's happening, and then that body becomes you.
Speaker 1: The identity of the self is surprisingly flexible. So what
Speaker 1: I've proposed is that what the body can control becomes
Speaker 1: the self. And this all pivots on predictability, and so
Speaker 1: one tragic lesson we can glean from this is what
Speaker 1: happens when a person gets damage to their peripheral nerves
Speaker 1: so they can no longer control their limb. And what
Speaker 1: happens is they can get a disorder called asomatic nosea,
Speaker 1: which means they now deny ownership of the limb that
Speaker 1: they can't control. So as somatic nosia means not knowing
Speaker 1: one's body. And in the clinics you'll find the strangest
Speaker 1: things where somebody will say this leg does not belong
Speaker 1: to me, and sometimes they'll insist that the limb belongs
Speaker 1: to somebody else. They'll attribute the leg to, say a
Speaker 1: dead friend or a relative, or a phantasm or a devil,
Speaker 1: or one of the doctors taking care of them. They'll
Speaker 1: say the leg was sewn onto her, but it's not hers.
Speaker 1: She'll explain that her own real limb was stolen or
Speaker 1: is simply missing. And in variance of this disorder, people
Speaker 1: will sometimes construe the limb as an animal, perhaps like
Speaker 1: a snake, with its own independent life force and intentions.
Speaker 1: But the point is it's no longer a part of
Speaker 1: their self. So I was surprised when I found there
Speaker 1: was no gold standard explanation for this in the literature.
Speaker 1: But you'll have no trouble guessing my proposal, which is
Speaker 1: that the brain can no longer control the limb, and
Speaker 1: so the limb falls from the brotherhood of the self.
Speaker 1: By the way, sometimes these patients have a small window
Speaker 1: of lucidity in which they re recognize their limb as
Speaker 1: their own, but it doesn't last long. I hypothesize that
Speaker 1: this might result when the leg happens to move the
Speaker 1: way that they had intended accidental predictability. That might be
Speaker 1: a feeling of wanting to move the foot to the left,
Speaker 1: and then the foot happens to move that way, which
Speaker 1: leads the owner to take credit for the action. And
Speaker 1: given a person's lifelong experience of controlling her leg It
Speaker 1: should come as no surprise that even a temporary impression
Speaker 1: of control can snap it back into alignment with the self,
Speaker 1: even if just for a moment. So what you can
Speaker 1: predict becomes part of the self. Now. One of the
Speaker 1: places this becomes really interesting is with relationships, because when
Speaker 1: you come to know someone well, you in a sense
Speaker 1: expand yourself. They become a part of you. Again. This
Speaker 1: is because the brain is a prediction machine. You've spent
Speaker 1: a lot of time with the people in your life,
Speaker 1: and so you have rich predictions about them. You have
Speaker 1: increasingly sophisticated guesses about what they're going to do in
Speaker 1: some situation, and in this sense they become a part
Speaker 1: of you. Now, your predictions about other people are never
Speaker 1: going to be perfect, and those people will often surprise you.
Speaker 1: And so the degree to which your spouse or friend,
Speaker 1: your family member remains unpredictable is the degree to which
Speaker 1: she or he remains different from the self, remains independent
Speaker 1: from you. Nonetheless, they are, to a greater or lesser degree,
Speaker 1: a part of your brain's notion of the self, because
Speaker 1: you have some degree of prediction about them, and as
Speaker 1: a result, you can be proud of their accomplishments and
Speaker 1: feel happy when they're happy, and sad when they're sad.
Speaker 1: And part of what's hard about a breakup or the
Speaker 1: death of a loved one is it something like a
Speaker 1: self contraction. Okay, so now we're set up to return
Speaker 1: to the question that I posed at the beginning of
Speaker 1: the episode. Why do soldiers march in lockstep? And I
Speaker 1: think you can now guess my hypothesis. It's not just
Speaker 1: about intimidation, it's not just about discipline. It's about giving
Speaker 1: each soldier the usion of a larger self. If you
Speaker 1: are an individual soldier, you experience this expansion of the self,
Speaker 1: this enlargement because there are all these other bodies moving
Speaker 1: in a way that is precisely predictable by your brain.
Speaker 1: Your brain sends out motor commands that say, okay, stomp
Speaker 1: my right leg exactly now. And after that command goes
Speaker 1: out from the brain and down the spinal cord, it
Speaker 1: witnesses the power of a thousand legs, all stomping at
Speaker 1: the same moment. Your brain has sent out a command,
Speaker 1: and you feel the earthshake as a result. It's empowering
Speaker 1: to be part of a group because your self now
Speaker 1: consists of thousands of bodies. There are a dozen ways
Speaker 1: to look at this issue of marching in lockstep socially,
Speaker 1: but from the neuroscience point of view, when you do
Speaker 1: stuff in synchrony with others, there's an expansion of the
Speaker 1: brain's construction of this self. So this is my hypothesis
Speaker 1: for why we see so much synchronization around us. You
Speaker 1: see this in Japanese festivals where everyone is doing the
Speaker 1: same thing at the same time. Or take the Hodge,
Speaker 1: which is this annual Islamic pilgrimage to Mecca. You've got
Speaker 1: pilgrims from all over the world travel to Mecca to
Speaker 1: flow around this big cube at the center of the
Speaker 1: Grand Mosque. Is very stunning to see hundreds of thousands
Speaker 1: of bodies swirling like a larger mega organism. And this
Speaker 1: is typical of religious ritual. If you only knew neuroscience
Speaker 1: and knew nothing about societal behavior, you might predict the
Speaker 1: existence of this sort of thing because the commands from
Speaker 1: each pilgrim's brain is multiplied by the feedback from hundreds
Speaker 1: of thousands of other pilgrims, and that kind of feedback
Speaker 1: is intoxicating to human brains. And as I said, you
Speaker 1: find this sort of synchronization in all religious rituals. Everyone
Speaker 1: is doing the same thing at the same time, ideally
Speaker 1: in the same costume. And I propose that it's not
Speaker 1: accidental everyone stands and sits at the same time, or
Speaker 1: genuflex or chants. When you look across religions, I suspect
Speaker 1: that the details of the rituals don't matter much at all. Instead,
Speaker 1: it's the allure of learning how to fuse your identity
Speaker 1: with a larger group. You think, wow, I can learn
Speaker 1: the steps, the moves, the words here and be part
Speaker 1: of a larger self. That is the promise that is
Speaker 1: being offered to you. You never find religious rituals where
Speaker 1: everything is desynchronized, where the promise is come into my religion,
Speaker 1: where we each do our own thing. You walk in
Speaker 1: whenever you want, you face wherever you want, Everyone sing
Speaker 1: and chant out of tune. You just don't see religions
Speaker 1: where there's no bigger voice, no bigger self acting in unison.
Speaker 1: And of course you find exactly the same synchronization in
Speaker 1: non religious ceremonies. One hypothesis about the origin of music
Speaker 1: and dancing is that this came from early primates who
Speaker 1: would synchronize with one another, and when we dance, we
Speaker 1: see this. If you're an observer of human behavior, it's
Speaker 1: hard to ignore that humans love to be synchronized on
Speaker 1: the dance floor. And you can imagine a bunch of
Speaker 1: early primates sitting around and all banging rocks together, making
Speaker 1: shouts or chants that aren't random but synchronized. You can
Speaker 1: see how the drive for a larger self could be
Speaker 1: at the root of this. And when you start looking
Speaker 1: for humans synchronizing, you see it everywhere. You see it
Speaker 1: in group exercise classes like yoga or dance or aerobics.
Speaker 1: Everyone's doing the same thing at the same time, and
Speaker 1: that synchronization fosters this sense of unity. You get the
Speaker 1: same thing in choirs where everyone sings together, or at
Speaker 1: music concerts, where the crowds synchronize their movements to the
Speaker 1: rhythm of the music. They sway, they clap, they sing
Speaker 1: along together. At sports events, you have fans synchronize their
Speaker 1: chance just like a protest marches. What's happening if you're
Speaker 1: at the event is that your brain sends commands to
Speaker 1: your larynx with the prediction that it will hear your
Speaker 1: voice in return. But now you hear your voice times
Speaker 1: a thousand, and you feel like your self is larger
Speaker 1: and more powerful. So let's wrap this up. My interest
Speaker 1: is in this question of where does your self end
Speaker 1: and others begin? And although you think you end at
Speaker 1: the borders of your skin, you're actually a flexible creature,
Speaker 1: extending past what you can see and feel, incorporating it
Speaker 1: tooferent times, your family, your partners, your teams, the culture
Speaker 1: in which you're embedded. And I think looking at this
Speaker 1: from the neuroscience point of view is a very powerful
Speaker 1: way to understand rituals and dancing inquires and religious ceremonies.
Speaker 1: Even on the political scale. It might shed light on
Speaker 1: our study of in groups and outgroups, and our understanding
Speaker 1: of things like patriotism. And this all fundamentally comes down
Speaker 1: to an extension of this self, which always reminds me
Speaker 1: to question, what would happen if you were born in
Speaker 1: a different culture, a different neighborhood, a different era in time.
Speaker 1: Would you be you? Presumably not in a way that
Speaker 1: we would recognize. You are wired up by the world
Speaker 1: that you happen to be in. All of it, to
Speaker 1: a lesser or greater degree, becomes part of what your
Speaker 1: brain considers your self. So I'm fascinated with this question
Speaker 1: of how we draw the limits of our selves. For example,
Speaker 1: I'm thinking some thoughts, and I jot notes throughout the week,
Speaker 1: and I go into my studio and record this podcast,
Speaker 1: and you listen to it. But it might be a
Speaker 1: week later after I've recorded it, or maybe you are
Speaker 1: listening to this long after I'm dead, and yet we're
Speaker 1: still communicating. I'm taking ideas from my head and capturing
Speaker 1: them in zeros and ones stored on a server somewhere,
Speaker 1: and eventually that gets transmitted over the Internet or maybe
Speaker 1: in a century, over Internet twelve to your device, and
Speaker 1: then my words reach you, and you're suddenly connected with me.
Speaker 1: I'm right next to you, I'm in your ear, I'm
Speaker 1: in your brain. My words make physical changes to the
Speaker 1: networks inside your head. And if we're alive at the
Speaker 1: same time, you can send me an email and I
Speaker 1: read the words on the screen that you wrote, and
Speaker 1: we are connected. And with our current communication technologies, this
Speaker 1: is more true than ever that our brains have the
Speaker 1: opportunity to expand the self, from literature to television, to
Speaker 1: podcasts to the Internet. We increasingly have the opportunity to
Speaker 1: become larger than we would otherwise be. Please visit eagleman
Speaker 1: dot com slash podcast for more information and to find
Speaker 1: further reading. Send me an email at podcast 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
Speaker 1: Eagleman and this is Inner Cosmos