Speaker 1: When you're trying to choose which ice cream flavor to get,
Speaker 1: what's actually happening in your brain? How do you decide?
Speaker 1: It seems pretty easy, but that's only if you don't
Speaker 1: see the storms of activity lighting up the brain. And
Speaker 1: how do you make long term decisions like that You're
Speaker 1: not going to eat the ice cream at all, but
Speaker 1: instead you're going to eat some broccoli. And what does
Speaker 1: any of this have to do with the ancient Greeks,
Speaker 1: or what alien hand syndrome is, or what the rules
Speaker 1: should be around how the president can launch the nuclear bomb.
Speaker 1: Welcome to Inner Cosmos with me David Eagleman. I'm a
Speaker 1: neuroscientist and author at Stanford and in these episodes we
Speaker 1: dive deeply into our three pound universe to uncover some
Speaker 1: of the most surprising aspects of our lives. Today's episode
Speaker 1: and next week's is about decision making. Although you generally
Speaker 1: feel like you're just moving through a day, decision making
Speaker 1: lies at the heart of everything we do. The complexity
Speaker 1: of the world presents itself to us, and we are
Speaker 1: constantly weighing alternatives. If you couldn't do that, you couldn't
Speaker 1: navigate the now, and you couldn't plan out your future.
Speaker 1: So by having a richer understanding of how choices battle
Speaker 1: it out in the brain, we can learn how to
Speaker 1: make better decisions for ourselves. And, as we're going to
Speaker 1: see next week, because this is a two partern, we'll
Speaker 1: even see how we can use this to build a
Speaker 1: better criminal justice system. So let's start at the very beginning.
Speaker 1: Should you choose the taco or the brito? Should you
Speaker 1: go for that T shirt or a more formal shirt.
Speaker 1: Should you take care of this email first or that
Speaker 1: bill payment first? Do you feel like the mint, chocolate
Speaker 1: chip or cookies and cream? On any day, you're making
Speaker 1: one thousand little decisions, which phone calls to make, which
Speaker 1: shooes to wear, whether to take the shorter path or
Speaker 1: the faster path, how exactly you should answer a question,
Speaker 1: what you should agree to on your schedule tomorrow. This,
Speaker 1: it turns out, is one of the most central things
Speaker 1: the brain does, make decisions. Your brain is a decision
Speaker 1: making machine. It takes the complexity of the world and
Speaker 1: it squeezes things down to single decisions. So how do
Speaker 1: brains do this? Now? When economists and psychologists first started
Speaker 1: looking at this question, they assumed that we humans act rationally.
Speaker 1: The idea is we look at our options, we add
Speaker 1: up the pros and cons, and we make the optimal decision.
Speaker 1: That's not necessarily how it goes with our brains. And
Speaker 1: in this episode and the next one, we're going to
Speaker 1: get a really good understanding why. So let's get going
Speaker 1: with these drawing where there are two ways to interpret
Speaker 1: the same image. You've probably seen these things. If you
Speaker 1: look at the picture one way, it looks like a rabbit,
Speaker 1: and if you keep staring at it you can see
Speaker 1: that suddenly it looks like a duck. So you probably
Speaker 1: saw this when you were a kid, But just in
Speaker 1: case you didn't, I'm putting it on the show notes
Speaker 1: at eagleman dot com slash podcast. The point is the
Speaker 1: image is what we call perceptually by stable, which is
Speaker 1: just a way of saying that when you stare at
Speaker 1: the picture, your brain can make one interpretation of what
Speaker 1: you're seeing or the other interpretation, and it switches back
Speaker 1: and forth. You see the rabbit and then the duck,
Speaker 1: and then the rabbit and then the duck. The critical
Speaker 1: thing to appreciate is that nothing on the page changes,
Speaker 1: so the only thing that's changing is something inside your brain.
Speaker 1: So some years ago I collaborated with my neurosurgery colleagues
Speaker 1: to study this sort of thing. Now, neuroscience, what I
Speaker 1: do is pretty different from brain surgery what a neurosurgeon does,
Speaker 1: but happily we tend to be friends and we can
Speaker 1: often help each other. So I accompanied surgeries while my
Speaker 1: colleagues were operating on people's brains. And you may know,
Speaker 1: one of the incredible things about neurosurgery is that you
Speaker 1: can do this while a patient is awake and talking
Speaker 1: to you. And this is because you can put little
Speaker 1: electrodes these are small metal wires into the brain and
Speaker 1: the brain has no pain receptors, so it doesn't hurt.
Speaker 1: The patient can't feel that. Now, why does the brain
Speaker 1: have no pain receptors. It's generally because nothing ever touches
Speaker 1: your brain. Your brain, which is about the consistency of jello,
Speaker 1: is well protected in the thick plates of the skull,
Speaker 1: so evolutionarily, there was no point in developing pain receptors
Speaker 1: in the brain anyway. As a consequence, a neurosurgeon only
Speaker 1: needs to use local anesthesia when making a cut on
Speaker 1: the scalp, and then they drill a burhole into the skull,
Speaker 1: and once the brain is exposed, you can poke things
Speaker 1: into the tissue while you and the patient are having
Speaker 1: a conversation about what it's like and what you find
Speaker 1: there is that this empire of eighty six billion neurons
Speaker 1: is constantly storming with activity. Every neuron in your head
Speaker 1: is having these little spikes of electrical voltage known as
Speaker 1: action potentials, and every neuron is firing off some tens
Speaker 1: or hundreds of these spikes every second of your life.
Speaker 1: Every idea you've ever had, every memory you can ever recollect,
Speaker 1: every choice that you've ever contemplated, is written in the
Speaker 1: language of these tiny, mysterious spikes. And using a very
Speaker 1: very tiny electrode think of a super small wire that
Speaker 1: you just push into the brain, you can eavesdrop on
Speaker 1: these spikes. Now, let's call the patient on the table, Marcia.
Speaker 1: So Marcia is wide awake and talking to me, and
Speaker 1: I can show her this bistable picture of the rabbit
Speaker 1: duck and ask her to tell me what she sees. Now,
Speaker 1: the moment that Marcia switches to rabbit or duck, her
Speaker 1: brain has made a decision. A decision doesn't have to
Speaker 1: be conscious in this case, it's a perceptual decision by
Speaker 1: her visual system, and the mechanics of this switchover are
Speaker 1: totally hidden under the hood. Now, what's interesting is that
Speaker 1: in theory, a brain should be able to see both
Speaker 1: the rabbit and the duck at the same time, but
Speaker 1: in reality, brains don't do that. What brains do is
Speaker 1: they take ambiguous data and they make a choice. In
Speaker 1: this case, it eventually remakes the choice, and it might
Speaker 1: switch back and forth over and over. But the point
Speaker 1: is that our brains are always crushing ambiguity down to
Speaker 1: a choice. So when Marsha's brain lands on the interpretation
Speaker 1: that the drawing is of a duck or a rabbit,
Speaker 1: we can listen through the electrode to the responses from
Speaker 1: a small number of neurons these cells in her brain.
Speaker 1: Some neurons shift to a higher rate of activity while
Speaker 1: other neurons slow down their activity. And that happens right
Speaker 1: when Marcia says, oh, now I see it as a duck,
Speaker 1: and then when she says, oh, now it's a rabbit again,
Speaker 1: the neurons are changing their activity. Now, the neurons we
Speaker 1: happen to be eavesdropping on are not by themselves responsible
Speaker 1: for the perceptual change. Instead, they're operating in concert with
Speaker 1: billions of other neurons. So the changes we're listening to
Speaker 1: are just pieces of this massive changing pattern taking hold
Speaker 1: across large swaths of brain territory. But the idea is
Speaker 1: that when one pattern wins out over the other in
Speaker 1: Marcia's brain, a decision has been landed upon. Now it's
Speaker 1: a rabbit. Now it's a duck. Now. Just as a
Speaker 1: side note, it's not always about the neurons speeding up
Speaker 1: or slowing down their spikes. Sometimes neurons change their pattern
Speaker 1: of activity in more subtle ways. They become synchronized or
Speaker 1: desynchronized with other neurons even while they're maintaining their original pace.
Speaker 1: Now here's the thing. Although we can look at this
Speaker 1: in Marsha's brain and correlate the changes with seeing the
Speaker 1: rabbit or the duck, the thing to appreciate is that
Speaker 1: your brain makes thousands of decisions every day of your life,
Speaker 1: and that dictates your experience of the world. What are
Speaker 1: you gonna wear today, who are you going to text today,
Speaker 1: How are you going to interpret what was meant by
Speaker 1: that email? Are you going to exercise today? Or are
Speaker 1: you gonna eat that bag of chips or pass it up.
Speaker 1: We don't typically chew on it, but these small decisions
Speaker 1: underlie every action we take. Who you are emerges from
Speaker 1: the brain wide battles for dominance that rage in your
Speaker 1: skull every moment of your life. So listening to that
Speaker 1: neural activity in Marsha's head, it's impossible not to be
Speaker 1: in awe because this is what every decision in the
Speaker 1: history of our species sounded like. Every marriage proposal, every
Speaker 1: declaration of war, every leap of imagination, every mission launched
Speaker 1: into the unknown, every act of kindness, every lie, every breakthrough,
Speaker 1: every decisive moment. It all happened right here in the
Speaker 1: darkness of the skull, emerging from patterns of activity in
Speaker 1: networks of biological cells. So let's take a closer look
Speaker 1: at what's happening behind the scenes during a decision. So
Speaker 1: imagine you're making a simple choice. You're standing in the
Speaker 1: drinksisle at the store, and you're trying to decide between
Speaker 1: two flavors of sports strength that you like equally. So
Speaker 1: you're looking at lemon and blueberry. Now from on the outside,
Speaker 1: someone's looking at you standing in the aisle. It doesn't
Speaker 1: look like you're doing much. You're simply stuck there in
Speaker 1: the aisle, looking back and forth between these two options.
Speaker 1: But inside your brain, a simple choice like this has
Speaker 1: unleashed a hurricane of activity. Now keep in mind that
Speaker 1: by itself, no single neuron has much influence. But each
Speaker 1: neuron is connected to thousands of others, and they in
Speaker 1: turn connect to thousands of others and so on. In
Speaker 1: this massive, loopy, intertwining network, they're all releasing chemicals that
Speaker 1: excite or depress each other. Within this web, a particular
Speaker 1: constellation of neurons represents the Lemon drink, and this pattern
Speaker 1: is formed from neurons that mutually excite each other. Now
Speaker 1: they're not necessarily next to each other. They might span
Speaker 1: distant brain regions involved in smell and taste, and vision
Speaker 1: and your unique history of memories involving lemons sports strengths.
Speaker 1: Each of these neurons by itself has very little to
Speaker 1: do with lemon. In fact, each neuron plays many different
Speaker 1: roles at different times in ever shifting coalitions. But when
Speaker 1: these neurons all become active collectively at the same time
Speaker 1: in this particular arrangement, that's the Lemons sports drink. To
Speaker 1: your brain. So as you're standing in front of the drinks,
Speaker 1: this federation of neurons eagerly communicates with one another, like
Speaker 1: the way that dispersed individuals link online. Now, these neurons
Speaker 1: aren't acting alone in their electioneering. At the same time,
Speaker 1: the competing possibility the blueberry flavored drink is represented by
Speaker 1: its own neural coalition, and thousands or millions of neurons
Speaker 1: there are talking with each other and trying to get
Speaker 1: the vote out. Now, each coalition lemon and blueberry, tries
Speaker 1: to gain the upper hand by intensifying its own activity
Speaker 1: and suppressing the others. Neural populations compete against one another,
Speaker 1: just like police parties struggle for dominance. They fight it
Speaker 1: out until one of them triumphs in this winner take
Speaker 1: all competition, and whichever network wins defines what you do next. Now,
Speaker 1: this is what is so cool about brains as compared
Speaker 1: to let's say, are digital computers. The brain is a
Speaker 1: machine that runs on conflict between different possibilities, and all
Speaker 1: these possibilities are always trying to outcompete the others, and
Speaker 1: there are always multiple options. Even after you've selected the
Speaker 1: lemon or the blueberry drink, you find yourself in a
Speaker 1: new conflict. Should I drink the whole thing right now?
Speaker 1: Part of you feels like it's a good idea to
Speaker 1: make sure you have plenty of hydration, And at the
Speaker 1: same time, part of you he recognizes that it's very
Speaker 1: sugary and you don't want to do too much of that.
Speaker 1: And part of you also knows you're going to have
Speaker 1: to go to the bathroom soon if you drink the
Speaker 1: whole thing. So whether you polish off the whole drink
Speaker 1: now or save some for later is simply a matter
Speaker 1: of the way that the infighting goes as a result
Speaker 1: of the ongoing conflict in the brain. You can argue
Speaker 1: with yourself, you can curse it yourself, you can cajole yourself.
Speaker 1: But who exactly is talking with whom? It's all you,
Speaker 1: but it's different parts of you now. As I said,
Speaker 1: we're not usually aware of these internal conflicts, but sometimes
Speaker 1: we can use simple tasks to bring this to the surface.
Speaker 1: For example, there was a simple psychological task introduced in
Speaker 1: the nineteen thirties, which we call the Stroop task, and
Speaker 1: it's very easy. All you do is you look at
Speaker 1: a word printed on a page, and the word might
Speaker 1: be in red ink or blue, or green or yellow,
Speaker 1: and all you need to do is say the color
Speaker 1: of the ink. So if I show you the word
Speaker 1: garage and the ink is yellow, all you do is
Speaker 1: you say yellow. Now that sounds very easy to do,
Speaker 1: But the trick is that the words I show you
Speaker 1: might themselves be color words. Like I show you the
Speaker 1: letters R, E, D, but the ink is in green.
Speaker 1: So when you see this, you're supposed to shout out green,
Speaker 1: but it proves very difficult. Or I show you the
Speaker 1: word purple written in yellow ink, or the word blue
Speaker 1: written in red ink. Check out some examples on the
Speaker 1: show notes. Now, the instructions are very easy. All you're
Speaker 1: supposed to do is say the color of the ink.
Speaker 1: So why is the stroop task so hard? It's because
Speaker 1: one network in your brain has the task of identifying
Speaker 1: the color of the ink and putting a name to it.
Speaker 1: But at the same time, you have competing networks in
Speaker 1: your brain that are responsible for reading words. And these
Speaker 1: are so proficient that word reading has become a deeply
Speaker 1: ingrained automatic process. And so you can feel the strugg
Speaker 1: as these systems contend with each other and to get
Speaker 1: the right answer. You have to actively suppress the strong
Speaker 1: impulse to read the word in favor of really concentrating
Speaker 1: on the ink color. So with a simple task like this,
Speaker 1: you can directly experience the conflict. But most of the
Speaker 1: time things are running so smoothly under the hood that
Speaker 1: you don't even realize that you have all these competing networks.
Speaker 1: And it's only under very special circumstances that it can
Speaker 1: become easy for us to witness in another person the
Speaker 1: internal conflict between the different parts of the brain. So
Speaker 1: this can happen when a person has a particular kind
Speaker 1: of epilepsy, where the epileptic seizures spread from one hemisphere
Speaker 1: to the other. In these cases, some patients have undergone
Speaker 1: what is called a split brain surgery, which the brain's
Speaker 1: two hemispheres get surgically disconnected from each other. So normally
Speaker 1: your two hemispheres are connected by a super highway of
Speaker 1: nerves called the corpus colosum, and this allows the right
Speaker 1: and left halves to coordinate and to work in concert. So,
Speaker 1: for example, if you are feeling chilly, both of your
Speaker 1: hands cooperate. One holds your jacket hem while the other
Speaker 1: tugs up the zipper. But When the corpus closum gets cut,
Speaker 1: the two hemispheres aren't talking anymore, and you can get
Speaker 1: a very wild and haunting clinical condition that's called alien
Speaker 1: hand syndrome. So the two hands can act with totally
Speaker 1: different intentions. So a person with a severed corpus colosum
Speaker 1: begins to zip up a jacket with one hand and
Speaker 1: the other hand the alien hand suddenly grabs the zipper
Speaker 1: and pulls it back down. Or the person might reach
Speaker 1: for a piece of pizza with one hand and their
Speaker 1: other hand leaps into action to slap the first hand.
Speaker 1: The normal conflict running in the brain now comes to
Speaker 1: the surface because the two hemispheres are now acting independently
Speaker 1: of one another. They're not working things out under the
Speaker 1: hood anymore. Alien hand syndrome typically fades in the weeks
Speaker 1: after surgery, as the two halves of the brain take
Speaker 1: advantage of any remaining connections to start coordinating again. But
Speaker 1: what it reminds us is that even when we think
Speaker 1: we're being single minded, our actions result from these immense
Speaker 1: battles that continually rise and fall in the darkness of
Speaker 1: the cranium. Now to appreciate some of the major competing
Speaker 1: systems in your brain. Consider a philosophy experiment known as
Speaker 1: the trolley dilemma. I spoke about this once about sixty
Speaker 1: episodes ago, but if you haven't heard this one, it
Speaker 1: paints an important point. So here's how it goes. A
Speaker 1: trolley is barreling down a train track and you are
Speaker 1: a bystander, and you notice that there are four workers
Speaker 1: who are doing repairs down the track, and you realize
Speaker 1: that they are going to get it and killed by
Speaker 1: this trolley. Then you notice that there's a lever right
Speaker 1: near you, and if you pull this lever, that'll divert
Speaker 1: the trolley onto a parallel track. But wait a minute.
Speaker 1: You realize that there's one worker on that track, and
Speaker 1: if you pull the lever, that one worker will get killed.
Speaker 1: So here's the question. Do you let four people get
Speaker 1: killed or do you pull the lever so that only
Speaker 1: one person is killed. When people are asked what they
Speaker 1: would do in this scenario, almost everyone pulls the lever.
Speaker 1: After all, it's better than only one person gets killed
Speaker 1: rather than four, right, But now consider a slightly different scenario.
Speaker 1: In the second scenario begins with the same premise that
Speaker 1: trolley is barreling down the track and four workers are
Speaker 1: going to get killed. But this time you're standing on
Speaker 1: a bridge that goes over the tracks, and you notice
Speaker 1: that there's a large man standing on the bridge watching
Speaker 1: the birds. And you realize that if you push him off,
Speaker 1: he'll land right on the track and his body will
Speaker 1: be sufficient to stop the trolley and save the four workers.
Speaker 1: So do you push him off? In this second scenario?
Speaker 1: Almost no one I talk with is willing to push
Speaker 1: the man. Why not? Well, when I ask them, they
Speaker 1: give answers like that would be murder and that would
Speaker 1: just be wrong. But wait, isn't it the same equation?
Speaker 1: In both cases? The question is would you trade one
Speaker 1: life for four? So why do the results come out
Speaker 1: so differently in the second scenario. Ethicists have addressed this
Speaker 1: problem from many angles, but brain imaging has been able
Speaker 1: to provide a fairly straightforward answer to the brain. The
Speaker 1: first scenario about pulling the lever, that's just a math problem.
Speaker 1: The dilemma activates regions that are involved in solving logical problems.
Speaker 1: But in the second scenario, where you have to physically
Speaker 1: interact with the man and push him to his death,
Speaker 1: that recruits additional networks. Into the decision. Now you have
Speaker 1: the involvement of brain regions involved in emotion. In this
Speaker 1: second scenario, you're caught in a conflict between two systems
Speaker 1: that have very different opinions. Your rational networks tell you
Speaker 1: that one death is better than four, but your emotional
Speaker 1: networks trigger this gut feeling that murdering a bystander is wrong.
Speaker 1: You're now dealing with these competing drives, with the end
Speaker 1: result that your decision is likely to change entirely from
Speaker 1: the first scenario. Now, the trolley dilemma sheds light on
Speaker 1: real world situations. Just think of modern warfare, which has
Speaker 1: become more like pulling the lever rather than pushing the
Speaker 1: man off the bridge. When a person pushed which is
Speaker 1: the button to launch a long range missile, it involves
Speaker 1: only the networks involved in logical problems. Operating a drone
Speaker 1: can become like a video game. Cyber attacks reconsequences at
Speaker 1: a distance, So the rational networks are at work here,
Speaker 1: but not necessarily the emotional networks. The detached nature of
Speaker 1: distance warfare reduces internal conflict, and it makes this easier
Speaker 1: to wage. So in the nineteen sixties there was a
Speaker 1: military thinker who suggested that the button to launch nuclear
Speaker 1: missiles should be implanted in the chest of the president's
Speaker 1: best friend. That way, if the president chooses to launch nukes,
Speaker 1: he'd have to inflict physical violence on his friend first,
Speaker 1: he'd have to tear him open, and that consideration would
Speaker 1: recruit emotional networks into the decision. After all, the world
Speaker 1: would not be better if we all behaved like row
Speaker 1: robots when making life and death decisions. Unchecked reason can
Speaker 1: be dangerous. Our emotions are actually a powerful and often
Speaker 1: insightful constituency, and we'd be remiss to exclude them from
Speaker 1: the parliamentary voting. Although the neuroscience is new, this intuition
Speaker 1: about having different drives has a long history. The ancient
Speaker 1: Greeks suggested that we should think of our lives like
Speaker 1: we are charioteers trying to hold on to two horses.
Speaker 1: We've got the horse of reason and the horse of passion,
Speaker 1: and each horse pulls slightly off center in opposite directions,
Speaker 1: and your job is to keep control of both horses,
Speaker 1: keeping yourself moving down the middle of the road. So
Speaker 1: I've asserted that emotions are really important and we shouldn't
Speaker 1: try to be like mister Spock. But I want to
Speaker 1: double click on that claim, and the way we can
Speaker 1: do that is by seeing what happens when a person
Speaker 1: loses the capacity to include emotions in decision making. So
Speaker 1: let's take someone like Hammy Myers, who I filmed in
Speaker 1: my television show called The Brain. Cammy is a former
Speaker 1: engineer and some years ago she got into a motorcycle
Speaker 1: accident and the consequence was damaged to her orbitofrontal cortex,
Speaker 1: which is the region just above the orbits of the eyes. Now,
Speaker 1: this is a critical region to integrate signals streaming in
Speaker 1: from the body, Signals that tell the rest of the
Speaker 1: brain what state her body is in. Is she hungry,
Speaker 1: is she nervous? Is she excited? Is she embarrassed? Is
Speaker 1: she thirsty? Is she joyful? Now? The interesting thing is
Speaker 1: that Cammy doesn't look like someone who has suffered a
Speaker 1: traumatic brain injury. But if you were to spend even
Speaker 1: five minutes with her, you would detect there's a problem
Speaker 1: with her ability to deal with decision making. So let's
Speaker 1: say you say, hey, do you want the lemon drinker
Speaker 1: the blueberry? And she can describe all the pros and
Speaker 1: the cons while the lemon drinks a little more sour,
Speaker 1: but the blueberry has more sugar, and so on. But
Speaker 1: she can't actually decide. She can't finalize a choice. Even
Speaker 1: the simplest situations leave her mired and indecision why. It's
Speaker 1: because she can no longer read her body's emotional summaries,
Speaker 1: and as a result, decisions become incredibly difficult for her.
Speaker 1: In other words, because of her brain injury, no particular
Speaker 1: choice is now tangibly different from any other choice, and
Speaker 1: without decision making, very little gets done. Tammy reports she
Speaker 1: often spends all day on the sofa, So her brain
Speaker 1: injury tells us something crucial about decision making. It's easy
Speaker 1: to think about the brain commanding the body from on high,
Speaker 1: but in fact, the brain is in constant feedback with
Speaker 1: the body. The physical signals from the body give a
Speaker 1: quick summary of what's going on and what to do
Speaker 1: about it. To land on a choice, the body and
Speaker 1: the brain have to be in close communication, and for
Speaker 1: that you need the orbit or frontal cortex. Now you can,
Speaker 1: of course understand this in your own life. Consider a
Speaker 1: situation like this. You get a package misdelivered to your door,
Speaker 1: but it belongs to your next door neighbors. So you
Speaker 1: go over to deliver it to them, But as you
Speaker 1: approach their gate, their dog growls and bares its teeth.
Speaker 1: So do you open the gate and press on to
Speaker 1: their front door? Your knowledge of the statistics of dog attacks,
Speaker 1: that's not the deciding factor here. Instead, the dog's threatening
Speaker 1: posture triggers a set of physiologic responses in your body.
Speaker 1: You get an increased heart rate, you get a tightening
Speaker 1: of the gut, a tensing of the muscles, you get
Speaker 1: pupil dilation, changes in blood hormones, opening of sweat glands,
Speaker 1: and so on. And all these responses are automatic and unconscious.
Speaker 1: So in this moment, standing there with your hand on
Speaker 1: their fence latch, there are a lot of external details
Speaker 1: you could assess, like what's the color difference between the
Speaker 1: dog's ears and nose, But your brain doesn't care about that.
Speaker 1: Way your brain really needs to know right now is
Speaker 1: whether you should face the dog or deliver the package.
Speaker 1: Another way, the state of your body helps you in
Speaker 1: this task. It serves as a summary of the situation.
Speaker 1: Your physiological signature can be thought of as a low
Speaker 1: resolution headline like this is bad or this is no problem,
Speaker 1: and that helps your brain decide what to do next.
Speaker 1: Most situations involve too many details to compute a purely
Speaker 1: logical decision. To guide the process, we need these abridged summaries.
Speaker 1: I am safe here, I am in danger here. The
Speaker 1: physiological state of the body maintains this instant two way
Speaker 1: dialogue with the brain, and every day we read the
Speaker 1: states of our bodies like this. But in most situations,
Speaker 1: our physiologic signals are more subtle and so we aren't
Speaker 1: aware of them. But these signals are crucial to steering
Speaker 1: the decisions we have to make. So consider being in
Speaker 1: a restaurant. This is the kind of place which leaves
Speaker 1: TAMMI paralyzed within decision. Do I want an appetizer, which one?
Speaker 1: What kind of salad dressing? Which dessert should I order?
Speaker 1: Thousands of choices bear down on the restaurant goer, with
Speaker 1: the end result that we spend hours of our lives
Speaker 1: staring at menus, making our neural networks commit to one
Speaker 1: decision over another. And although we don't commonly realize it,
Speaker 1: our body helps us to navigate this boggling complexity. Take
Speaker 1: the choice of which Italian dish are going to order?
Speaker 1: There's too much data for you to grapple with. You
Speaker 1: can think about calories or price, or salt content, taste
Speaker 1: or whatever. There's lots of data to draw from here.
Speaker 1: But if you were a robot, you'd be stuck here
Speaker 1: all day trying to make your decision with no obvious
Speaker 1: way to trade off. Which details matter more. To land
Speaker 1: on a choice, you need a summary of some sort,
Speaker 1: and that's what the feedback from your body gives you.
Speaker 1: For example, thinking about your budget might make your palm sweat,
Speaker 1: or you might salivate thinking about the last time you
Speaker 1: consumed the angel hair pasta, or thinking about the excessive
Speaker 1: creaminess of the alfredo might put a cramp in your intestines.
Speaker 1: You simulate your experience with one pasta, and then you
Speaker 1: simulate the next and the next, and your bodily experience
Speaker 1: helps your brain to quickly place a value on the
Speaker 1: first pasta offering, and another on the second pasta, and
Speaker 1: on the third and so on, and this is what
Speaker 1: allows you to tip the balance in one direction or another.
Speaker 1: You don't just extract the data from the pasta descriptions,
Speaker 1: you so feel the data. These emotional signatures are more
Speaker 1: subtle than the ones related to facing down a barking dog.
Speaker 1: But the idea is the same. Every choice that you
Speaker 1: face is marked by a bodily signature, and that helps
Speaker 1: you decide. Earlier, when I was deciding between the lemon
Speaker 1: and the blueberry, exercise drink, I told you that there
Speaker 1: was a battle between networks. The physiological states from my
Speaker 1: body are the key things that help tip that battle,
Speaker 1: that allow one network to win over another. But for Tammy,
Speaker 1: because of her brain damage, she can't integrate her bodily
Speaker 1: signals into her decision making, so she has no way
Speaker 1: to rapidly compare the overall value between options. She has
Speaker 1: no way to prioritize the dozens of details that she
Speaker 1: can articulate. That's why Tammy stays on the soface so
Speaker 1: much of the time. None of the choices in front
Speaker 1: of her carry any particular emotional value. There's no way
Speaker 1: to tip one network's campaign over any other, so the
Speaker 1: debates in her neural parliament continue along in deadlock. Because
Speaker 1: the conscious mind has low bandwidth, you don't typically have
Speaker 1: full access to the bodily signals that tip your decisions.
Speaker 1: Most of the action lives far below awareness. Nonetheless, these
Speaker 1: signals can have far reaching consequences on the type of
Speaker 1: person you are and who you'll become. So what we've
Speaker 1: been introduced to today is this incredible thing that brains
Speaker 1: do called decision making, where neurons consider options and things
Speaker 1: are set up so that one coalition can smash everything
Speaker 1: else down so you get to one outcome. And even
Speaker 1: though we typically don't give it much consideration, decision making
Speaker 1: lies at the heart of everything we do during a day.
Speaker 1: Without the ability to consider alternatives and weigh them and
Speaker 1: select one over others, the complexity of the world would
Speaker 1: just paralyze us. And one of the lessons that surfaced
Speaker 1: is that although you feel like you have a single identity,
Speaker 1: you're not of a single mind. Instead, you're a collection
Speaker 1: of many competing neural networks. You are, in a sense,
Speaker 1: a machine built of conflict. So what we covered is
Speaker 1: that every decision you make involves your past experiences stored
Speaker 1: in the states of your body, as well as an
Speaker 1: analysis of your presence situation. Do I have enough money
Speaker 1: to buy X instead of Y? Is options Z available?
Speaker 1: But there's one more part to the story of decisions,
Speaker 1: perhaps the most important part of all, and that is
Speaker 1: predictions about the future. And that is where we're going
Speaker 1: to pick up next week. Until then, keep making good
Speaker 1: decisions and I'll see you next time. Go to eagleman
Speaker 1: dot com slash podcast for more information and to find
Speaker 1: further reading, and send me an email at podcast at
Speaker 1: eagleman dot com with questions or discussions, and check out
Speaker 1: and subscribe to Inner Cosmos on YouTube for videos of
Speaker 1: each episode and to leave comments. Until next time, I'm
Speaker 1: David Eagleman, and you made the very nice decision to
Speaker 1: join me here in the Inner Cosmos