Speaker 1: How far in the past do you live? Why are
Speaker 1: live television shows not actually live? And what does any
Speaker 1: of this have to do with nuclear bombs or car
Speaker 1: accidents where the Boeing airlines crash in Ethiopia or volcanoes
Speaker 1: or the last episode of The Sopranos. Welcome to Inner
Speaker 1: Cosmos with me David Eagleman. I'm a neuroscientist and an
Speaker 1: author at Stanford University, and I've always been obsessed with
Speaker 1: how we perceive time. In this episode, I'm going to
Speaker 1: dive into an issue about time perception that's always intrigued me,
Speaker 1: which is how long do we have to wait before
Speaker 1: we have a conscious perception of something that just happened
Speaker 1: in the world. And that leads to a very wild question,
Speaker 1: will you perceive the event that kills you? So imagine
Speaker 1: that you're walking down the sidewalk and you're enjoying the sunshine,
Speaker 1: and you're sipping your coffee from a paper cup and
Speaker 1: watching two dogs wrestling around and having fun in the distance,
Speaker 1: and suddenly, from a crane perched ten stories in the air,
Speaker 1: a piano falls and lands right on top of you.
Speaker 1: The question we want to dive into today is will
Speaker 1: you be aware of that final moment, or while you
Speaker 1: feel you're happily watching the dogs and sipping the coffee,
Speaker 1: will the footage just end? Now this is not an
Speaker 1: idle question. It's one that allows us to dig deep
Speaker 1: into what happens in the brain, and it's one that
Speaker 1: sometimes gets wrestled with in courts of law. So let's
Speaker 1: start this story in twenty seventeen when the United States
Speaker 1: it proved a new generation of the Boeing seven thirty
Speaker 1: seven airplane. This was called the Boeing seven thirty seven Max,
Speaker 1: and it was a great evolution for this leading airliner company,
Speaker 1: and it immediately produced hundreds of orders that came pouring
Speaker 1: in from around the world. So everything looked great. But
Speaker 1: then in October of twenty eighteen, a seven thirty seven
Speaker 1: Max took off from Jakarta on its way to Indonesia,
Speaker 1: and thirteen minutes after takeoff, it crashed into the Java
Speaker 1: Sea and it killed all one hundred and eighty nine
Speaker 1: people on board. So that immediately triggered investigations into whether
Speaker 1: something about this new airplane design had anything to do
Speaker 1: with the crash, and those investigations uncovered a serious issue.
Speaker 1: It turns out that some previous seven thirty seven Max
Speaker 1: flights had had serious problems. There hadn't been a crash,
Speaker 1: but nonetheless the passengers had been traumatized. And the problems
Speaker 1: had to do with the failure of a sensor that
Speaker 1: detects the angle of attack, which is just the angle
Speaker 1: between the wing and the wind, and that mattered because
Speaker 1: it affects the amount of lift that the airplane gets. So,
Speaker 1: without going into details, it surfaced that there was this
Speaker 1: inherent design flaw in the seven thirty seven Maxes that
Speaker 1: made these planes really hard to control in some circumstances
Speaker 1: and really dangerous. So the Federal Aviation Administration and Boeing
Speaker 1: moved quickly to give out warnings and training advisories to
Speaker 1: all the operators of the seven thirty seven Max series
Speaker 1: to avoid this kind of problem. But before these got implemented,
Speaker 1: something awful happened. In March of twenty nineteen, Ethiopian Airlines
Speaker 1: Flight three h two crashed because of this exact same problem,
Speaker 1: and that crash instantly killed all one hundred and fifty
Speaker 1: seven people on board, and that led to an immediate
Speaker 1: grounding of all seven thirty seven Max airplanes around the planet.
Speaker 1: Now there are hundreds of angles to the enormous legal
Speaker 1: case around the crash of the Ethiopian Airlines flight, including
Speaker 1: negligence and collusion. But I'm going to zoom in on
Speaker 1: a part of the lawsuit that's currently in the courts,
Speaker 1: and that part of the legal argument comes down to
Speaker 1: millions of dollars and the final half second, and that's
Speaker 1: where neuroscience unexpectedly intersects with aviation. In the aftermath of
Speaker 1: the crash, Boeing executives met with the victims' families and
Speaker 1: they pledged a one hundred million dollar fund for the families,
Speaker 1: separate from any lawsuit. And then Boeing settled for two
Speaker 1: and a half billion with the Justice Department, and they
Speaker 1: agreed to pay five hundred million more to the victim's beneficiaries.
Speaker 1: Then they also paid other fines for alleged misleading statements
Speaker 1: and so on. But Boeing's attorneys argued that they shouldn't
Speaker 1: have to pay out any money for pain and suffering. Now,
Speaker 1: let's be clear on what the legal argument is here.
Speaker 1: In legal terms, while the plane was tilting and heading
Speaker 1: towards the ground, the nausea and terrible fear falls into
Speaker 1: a legal category of mental anguish. But that's a different
Speaker 1: category of damages than pain and suffering, which is what
Speaker 1: happens between a physical injury and the time of death.
Speaker 1: Now this is grim stuff, but it's the kind of
Speaker 1: analysis that comes up in courtrooms all the time. Imagine
Speaker 1: that there's a factory and there's a poorly braced machine
Speaker 1: and it falls on a worker, and that person ends
Speaker 1: up pinned for hours and bleeding out, and they're conscious
Speaker 1: the whole time of what is happening to them, and
Speaker 1: they pass away. Now, that would fall under the legal
Speaker 1: category of pain and suffering. That category of damages starts
Speaker 1: at the moment of physical injury and runs until the
Speaker 1: time of death. But Boeing's attorneys argued that while there
Speaker 1: certainly was mental anguish during the six minute roller coaster ride,
Speaker 1: there was no pain in suffering that could be argued
Speaker 1: in this case. Why because the planes impact with the
Speaker 1: ground caused instantaneous death. What Boeing said is that the
Speaker 1: victims died painlessly because the airplane crashed into the ground
Speaker 1: so fast that their brains didn't have time to process
Speaker 1: pain signals. In other words, there was no time between
Speaker 1: injury and death. Just to be clear, Boeing's attorneys aren't
Speaker 1: arguing that the families can't recover massive damages in the lawsuit.
Speaker 1: They're just talking about this specific category of pain and suffering,
Speaker 1: and this isn't an unusual argument in wrongful death cases
Speaker 1: like plane crashes and car accidents, to argue in a
Speaker 1: courtroom about what someone's experience would have been like in
Speaker 1: their final moments, and therefore whether they experienced any pain
Speaker 1: and suffering. It comes down to the issue of whether
Speaker 1: the passengers were aware that the plane hit the ground,
Speaker 1: and this boils down to a question that can only
Speaker 1: be addressed by neuroscience. Time is one of the most
Speaker 1: important elements in our lives, but how we perceive time
Speaker 1: is one of the least understood. So I've devoted a
Speaker 1: large part of my career to try to figure out
Speaker 1: our experience of time, and the lesson that surfaces is
Speaker 1: that our perceptual experience is the result of lots of
Speaker 1: computation in the brain and it doesn't necessarily map on
Speaker 1: to what reality actually is. Now. In a different episode,
Speaker 1: I talked about time seeming to run in slow motion.
Speaker 1: Many people have had this impression when they're in a
Speaker 1: life threatening situation that an event seemed to last longer
Speaker 1: than normal. And in that episode, I told the story
Speaker 1: about when I was eight years old and fell off
Speaker 1: of the roof of a house inner construction and time
Speaker 1: seemed to run in slow motion, and how that eventually
Speaker 1: led to me becoming a neuroscientist because I grew so
Speaker 1: fascinated with this almost totally unexplored area. In this episode,
Speaker 1: I'm going to take you on a totally different path
Speaker 1: through time perception, and we're going to see some mind
Speaker 1: bending surprises along the way. Now, to tackle something as
Speaker 1: big and mysterious as time, it helps begin with something
Speaker 1: very simple, and many years ago I stumbled on a
Speaker 1: simple visual illusion that ended up opening big doors for
Speaker 1: my understanding of time. And that illusion was first noticed
Speaker 1: in the nineteen twenties. It's called the flash lag illusion.
Speaker 1: And here's how it goes. Imagine you're looking out your
Speaker 1: window and you see a bicyclist zipping along the road
Speaker 1: in front of your house, going from the left side
Speaker 1: to the right side, and as they're going by, a
Speaker 1: bright light flashes very briefly on their helmet. Flash. That's
Speaker 1: all I need you to picture. Bike moves along light
Speaker 1: flashes on their helmet. So what hits your eye is
Speaker 1: the bike and the flash in the same location, but
Speaker 1: what you consciously perceive is something different. The way it
Speaker 1: looks to you is that the bike was some distance
Speaker 1: ahead of the flash. It doesn't look like they're in
Speaker 1: the same spot. Now, this flash lag illusion is very
Speaker 1: easy to demonstrate and to quantify, and you can see
Speaker 1: demos of this at Eagleman dot com Slash podcast. But
Speaker 1: the question is why does this happen? So what had
Speaker 1: been proposed in the literature is that maybe what's happening
Speaker 1: is your visual system watches the bicyclist, but it doesn't
Speaker 1: see the bike where it is right now, but instead
Speaker 1: your brain is guessing where the bike will be in
Speaker 1: the next moment. Your brain is making a prediction, and
Speaker 1: that's what you see is this predicted position a little
Speaker 1: bit ahead. But your brain doesn't have that luxury with
Speaker 1: the flash because it didn't know that was about to happen,
Speaker 1: and so it can't make any predictions there. And so
Speaker 1: the bike looks farther ahead to the right in this case,
Speaker 1: and the flash appears exactly where it happened. Now, I
Speaker 1: had some reasons to doubt that framework. So I set
Speaker 1: up a very simple experiment which I presented to test participants.
Speaker 1: Imagine on the screen you're watching the bike moving to
Speaker 1: the right, and I have a flash appear for just
Speaker 1: one frame, and it's perfectly lined up with the bike. Now,
Speaker 1: that's what gives you the flashlight illusion. But now I'm
Speaker 1: going to do one of three things at random after
Speaker 1: the flash is over. Either the bike keeps going, or
Speaker 1: the bike instantly stops, or the bike reverses direction. The
Speaker 1: key thing to note here is that everything up to
Speaker 1: and including the flash is identical, and all I'm doing
Speaker 1: is changing what happens in the future of the flash.
Speaker 1: So if prediction is happening, if your brain is just
Speaker 1: guessing ahead where the moving bike is, then of course
Speaker 1: we'll expect to see the same thing every time, which
Speaker 1: is that the bike should be ahead of the flash
Speaker 1: to the right, because it shouldn't matter what happens after
Speaker 1: the flash is already gone. But here's what actually happens.
Speaker 1: If the bike keeps going, it looks like it's ahead
Speaker 1: of the flash on the right, as expected. But if
Speaker 1: the bike stops instantly in the frame after the flash,
Speaker 1: it looks like the flash was on the helmet, there's
Speaker 1: no more illusion. And if the bike reverses its direction
Speaker 1: immediately after the flash, then it looks like the flash
Speaker 1: is off the helmet. In the other direction, the bike
Speaker 1: is off to the left now instead of to the right. Now.
Speaker 1: Why is that's such a weird result. It's so weird
Speaker 1: because I'm asking you what you see at the moment
Speaker 1: of the flash, and your answer depends on what happens
Speaker 1: in the future of the flash. And remember, these conditions
Speaker 1: are randomly interleaved, so you can't know what's actually going
Speaker 1: to happen on any given trial. So there's only two
Speaker 1: possibilities here. Either my test subjects were clairvoyantly seeing into
Speaker 1: the future, which I don't think is happening, or the
Speaker 1: perception that we attribute to some moment in time actually
Speaker 1: depends on what happens next. In other words, what we
Speaker 1: think happen in some moment depends on what happens after
Speaker 1: that moment. Now, this is a wild finding because it
Speaker 1: shows right away that the brain is not using prediction
Speaker 1: guessing ahead. Instead, it's something more like filling in behind.
Speaker 1: The key is that after the flash, your brain continues
Speaker 1: to collect up in information and it retrospectively says what
Speaker 1: it thinks it saw. Nothing is moving backwards in time.
Speaker 1: The correct way to think about this is to think
Speaker 1: about two timelines. There's time in the real world and
Speaker 1: there's time in your head. This is physical time and
Speaker 1: subjective time. And the timeline in your head is simply
Speaker 1: shifted later. It's a delayed version of what is happening
Speaker 1: in the real world. And this is because it takes
Speaker 1: time for signals to move around in the brain and
Speaker 1: get processed. So by the time the information from the
Speaker 1: flash gets fully through the machinery, new information about the
Speaker 1: movement of the bike has been streaming in. So by
Speaker 1: the time you become consciously aware of the flash, your
Speaker 1: brain has incorporated some information that happened after the flash.
Speaker 1: So I published this in the journal Science, and I
Speaker 1: called this phenomenon postdiction as opposed to prediction, and it
Speaker 1: actually became the most highly cited paper of my career
Speaker 1: so far because what it surfaces, in a very simple way,
Speaker 1: is a fundamental feature of our perception, which is that
Speaker 1: we live in the past. The brain collects information and
Speaker 1: that flows around and eventually comes to a conclusion and
Speaker 1: gives you a story of what happened in the world
Speaker 1: out there, and then we think, oh, that's what's happening
Speaker 1: right now. So when I say we're living in the past,
Speaker 1: I mean that by the time we think the moment
Speaker 1: now has occurred, it's already happened. Remember that signals in
Speaker 1: the brain move very slowly. In the cerebral cortex, which
Speaker 1: is the wrinkly outer covering of the brain, most signals
Speaker 1: are traveling around at one meter per second, which is
Speaker 1: three hundred million times slower than signals in fiber optic cables.
Speaker 1: So your brain has a challenge, which is that it's
Speaker 1: true trying to understand what's going on in the outside world.
Speaker 1: But it's big and it's made of billions of cells,
Speaker 1: and so its only good solution is to wait until
Speaker 1: all the signals have been collected up and compiled. It
Speaker 1: gathers the signals from the various senses, and once all
Speaker 1: that information has arrived, your brain develops a conscious narrative
Speaker 1: about what just happened. And the consequence is that your
Speaker 1: conscious mind lives behind reality. When I clap my hands
Speaker 1: together and we think the moment now is occurring, we're wrong.
Speaker 1: It already happens. Some time ago. Our brains had to
Speaker 1: collect the information from the visual system, the auditory system
Speaker 1: process that, stitch it all together and serve up a story,
Speaker 1: and then you say, oh, I just heard a clap.
Speaker 1: The consequence is that your perception of the world is
Speaker 1: something like the airing of a live television show like
Speaker 1: Saturday Night Live, which is not actually live, but it's
Speaker 1: aired with a delay in case someone cusses or falls down,
Speaker 1: or there's a wardrobe mishap, and so it goes with
Speaker 1: your consciousness. It is delayed by a small window while
Speaker 1: your brain puts together its story. What you perceive is
Speaker 1: a delayed version of reality. For all you know, this
Speaker 1: podcast is already over. Okay, not that far in the past,
Speaker 1: but how far in the past are we well in
Speaker 1: the flash lag effect, I was able to show that
Speaker 1: we were about a tenth of a second behind what
Speaker 1: was happening out there, one hundred milliseconds. But that was
Speaker 1: measured from experiments I did in the visual system. And
Speaker 1: for a unified perception of the world with all its
Speaker 1: sights and sounds and textures, you need to wait for
Speaker 1: all the information to stream in from all of the senses.
Speaker 1: And that means that if your brain wants to wait
Speaker 1: to collect up all the information before putting together a
Speaker 1: story of what happened, it needs to wait for the
Speaker 1: slowest information, which is from your toes. That information has
Speaker 1: to climb all the way up the nerves and your
Speaker 1: legs and then up the entire spinal cord all the
Speaker 1: way to your brain. And although the nerves that carry
Speaker 1: touch information are fast compared to some other kinds of nerves,
Speaker 1: they're super slow compared to say, the speed of signals
Speaker 1: in your computer, and so the whole thing takes more
Speaker 1: than one hundred milliseconds. And what I realized was that
Speaker 1: if your brain wants a unified perception of what just
Speaker 1: happened in the world, rather than different pieces streaming at
Speaker 1: different times, it has no choice but to wait for
Speaker 1: all that information to arrive. And one way to demonstrate
Speaker 1: this is if I touch your nose and your toe
Speaker 1: at the same time, you will feel that as simultaneous.
Speaker 1: It's not like you feel the signal from your nose
Speaker 1: and then you feel it later from your toe, even
Speaker 1: though the signal from your nose gets to your brain
Speaker 1: much more quickly. So the question is does your brain
Speaker 1: capture the information from the nose and then say, Okay, cool,
Speaker 1: I've got that, but I'm not going to perceive anything
Speaker 1: yet because something else might be coming up the pipeline. Yes,
Speaker 1: I think that's actually what happens. And because the brain
Speaker 1: has to wait for this slow information to arrive, this
Speaker 1: leads to the bizarre but testable prediction that tall people
Speaker 1: live further in the past than short people. So I
Speaker 1: mentioned my prediction once on a live interview on NPR,
Speaker 1: and then I drove back to my lab and I
Speaker 1: opened my email, and I saw that I had received
Speaker 1: dozens of emails from people who said, I'm short, and
Speaker 1: I really appreciate what you said. But let's get back
Speaker 1: to this question of how far behind reality does your
Speaker 1: consciousness lag. In the nineteen seventies, a neuroscientist named Benjamin
Speaker 1: Libbitt did some studies with people who were undergoing neuros,
Speaker 1: and those studies suggested that we lag as much as
Speaker 1: five hundred milliseconds half a second. I'm not going to
Speaker 1: go into the details of his experiment here, but I've
Speaker 1: linked the research on the podcast website. So Libbett's claim
Speaker 1: was that we are half a second in the past,
Speaker 1: and it's worth noting that it might be impossible for
Speaker 1: us to measure the moment of onset of conscious experience,
Speaker 1: so the exact time delay is very hard to know
Speaker 1: for sure, but for now, let's call it about half
Speaker 1: a second in the past. And this happens because the
Speaker 1: brain needs to collect all the signals from the eyes
Speaker 1: and the ears and the skin, and those need to
Speaker 1: travel along their respective nerves and enter the brain in
Speaker 1: the place that they come in in the primary sensory
Speaker 1: cortex for each sense, and then move to the secondary
Speaker 1: sensory cortex and tertiary, and the signals splash out into
Speaker 1: multimodal areas, and everything needs to get stitched together into
Speaker 1: a story of what just happened. And by the time
Speaker 1: this whole process completes itself, the event itself in the
Speaker 1: world is already long gone. Now the more I study this,
Speaker 1: the more I realized that this strange fact has an
Speaker 1: interesting and unappreciated consequence. You probably won't perceive the event
Speaker 1: that kills you, at least if that event happens suddenly.
Speaker 1: So let's return to this scenario of you walking down
Speaker 1: the street and joining your coffee and suddenly the piano
Speaker 1: falls on you. That would be so terrible, right, But
Speaker 1: what we've just seen is that it takes time for
Speaker 1: signals to come together to form a conscious story. So
Speaker 1: that means that if your brain gets damaged before the
Speaker 1: signals come together, then it says though the footage suddenly ends.
Speaker 1: And this would be true not only for our pianos,
Speaker 1: but for any unexpected event like a bullet or a
Speaker 1: bomb explosion. The damage to the brain would happen much
Speaker 1: faster than the time it takes to process the signals
Speaker 1: and come to a conscious conclusion. Now, I've been studying
Speaker 1: this in my lab for many years, and so I
Speaker 1: was really amazed when I saw the great author Cormick
Speaker 1: McCarthy point to this in his post apocalyptic novel The Road.
Speaker 1: So at one point in the novel, the main character
Speaker 1: levels his pistol on a bad guy who was trying
Speaker 1: to attack him, and the bad guy says, quote, you
Speaker 1: won't shoot My companions will hear the shot, And our
Speaker 1: hero says, yes, they will, but you won't. And the
Speaker 1: bad guy says, how do you figure that? And our
Speaker 1: hero says, because the bullet travels faster than the sound,
Speaker 1: it'll be in your brain before you can hear it.
Speaker 1: To hear it, you'll need a frontal lobe and things
Speaker 1: with names like colliculus and temporal gyrus, and you won't
Speaker 1: have them anymore. They'll just be soup. In other words,
Speaker 1: what McCarthy was pointing out is the same issue, which
Speaker 1: is that you need your brain to perceive. No brain,
Speaker 1: no perception. Now, one of the most popular shows in
Speaker 1: television history was The Sopranos, and if you didn't see it,
Speaker 1: it was an intimate story of a mafia family in
Speaker 1: New Jersey, and it was told over eight years. It
Speaker 1: had tens of millions of dedicated fans, and so when
Speaker 1: the finale to the whole show finally arrived, everyone was
Speaker 1: tuned in to see how the show would end. The
Speaker 1: series centers on Tony Soprano, this mafia head in New Jersey,
Speaker 1: and the thing about Tony Soprano is that he's always
Speaker 1: struggling to balance his fan family life and his role
Speaker 1: as a mob boss. So he has panic attacks and
Speaker 1: we get to see him in therapy sessions with his
Speaker 1: psychiatrist throughout the series, and if you've never seen it,
Speaker 1: you can imagine there are life threatening complications all the
Speaker 1: time with other mobsters inside his family and outside, and
Speaker 1: specifically with the New York City based Lupertazzi family, which
Speaker 1: had been working to take down the Soprano family by
Speaker 1: decapitating them, in other words, by taking out their leadership
Speaker 1: some of Tony's family and collaborators. They were gunned down,
Speaker 1: one was put in a coma, and shots were taken
Speaker 1: to Tony. But now in the final episode, things seem
Speaker 1: to have calmed down. Tony seems to be in control
Speaker 1: of his New Jersey empire, and yet as the episode
Speaker 1: is coming to an end, something seems just slightly off.
Speaker 1: Tony is sitting in a diner eating onion rings and
Speaker 1: listening to Don't Stop Believing by Journey on the jukebox.
Speaker 1: The camera passes by people here and there. It's hard
Speaker 1: to tell if anyone seems out of place, like when
Speaker 1: the camera follows one seemingly random man who goes into
Speaker 1: the bathroom behind where Tony is sitting, and we see
Speaker 1: Tony's daughter park across the street, and she runs across
Speaker 1: the street to join him, and we hear the bell
Speaker 1: on the door, which is presumably her entrance, and he
Speaker 1: looks up from his food, and then the video and
Speaker 1: audio cut to blackness and silence, So fans went into
Speaker 1: an uproar. What just happened to the show? Was there
Speaker 1: a broadcasting hiccup? Was this a technical problem with their television?
Speaker 1: But it wasn't. The show ends that way because we
Speaker 1: are in Tony's point of view, and suddenly there simply
Speaker 1: is no more point of view. The fragile circuits necessary
Speaker 1: for Tony's brain to construct a story have been wrecked
Speaker 1: by a bullet, and the damage happens before they've been
Speaker 1: able to stitch together a story about that last half
Speaker 1: second of his life. Now, this scene of Tony's death
Speaker 1: connected back to an earlier snippet of dialogue from two
Speaker 1: seasons earlier, in which Bobby Bachlieri says to Tony, quote,
Speaker 1: you probably don't even hear it when it happens. Right,
Speaker 1: because of the slow propagation of signals in the nervous
Speaker 1: system and the slow stitching together of consciousness, you might
Speaker 1: never even be aware that a gun fired, or that
Speaker 1: a bomb exploded, or that a truck just crashed through
Speaker 1: the wall, or a jet engine fell on your head.
Speaker 1: One moment you're present and thinking, and the next moment,
Speaker 1: your machinery for thought is gone. The broadcast of consciousness
Speaker 1: just cuts way to appreciate the sluggishness of your perception
Speaker 1: is to compare it to the speed of the machinery
Speaker 1: that we're surrounded with. I recently read this great article
Speaker 1: on the anatomy of a car crash, which was in
Speaker 1: the Australian magazine Drive, and the article describes what happens
Speaker 1: when a car is hit in the driver's door by
Speaker 1: another car traveling at fifty kilometers per hour. At zero
Speaker 1: milliseconds is when the other car first touches the driver's door.
Speaker 1: At one millisecond, the car's door pressure sensor detects a
Speaker 1: pressure wave. From here, over the next few milliseconds, different
Speaker 1: sensors pick up on the crash vibrations. So I'll skip
Speaker 1: ahead to five milliseconds, when the car's crash computer starts
Speaker 1: searching for what's going on, trying to work out the
Speaker 1: severity of the crash. By six point five milliseconds, the
Speaker 1: door pressure sensor is registering peak pressures, which causes by
Speaker 1: seven milliseconds the crash computer to con firm that the
Speaker 1: crash is serious and send the next steps into action.
Speaker 1: At eight milliseconds, the computer sends a signal to the
Speaker 1: side airbag, and by eight point five milliseconds the airbag
Speaker 1: fires off. By fifteen milliseconds, it bursts through the foam
Speaker 1: and begins to fill. By seventeen milliseconds, it covers the
Speaker 1: driver's chest and pushes the shoulder away from the impact zone,
Speaker 1: and then by a few milliseconds later, it's pushing the
Speaker 1: chest away. All the while the physical structure of the
Speaker 1: car is crumpling in such a way as to transfer
Speaker 1: the energy away from the driver. By twenty seven milliseconds,
Speaker 1: a mechanism in the seat moves the driver's pelvis away
Speaker 1: from the impact zone, and the air bag starts its
Speaker 1: controlled deflation. Over the next tens of milliseconds, the driver
Speaker 1: and airbag move together as the structure of the car deforms,
Speaker 1: and by fifty milliseconds, the crash computer unlocks the car's doors.
Speaker 1: By seventy milliseconds, the driver moves back towards the middle
Speaker 1: of the car, and the air bag continues to deflate.
Speaker 1: At this point, seventy milliseconds in, the engineers classify the
Speaker 1: crash as complete. Now here's the zinger. After about another
Speaker 1: four hundred milliseconds, the driver becomes aware that there was
Speaker 1: a collision. From the machinery's point of view, the entire
Speaker 1: show is over before consciousness even flickers onto the screen.
Speaker 1: If you ever talk to someone who's been in a
Speaker 1: car accident, you'll already know that no one ever sees
Speaker 1: the airbag deploy They have the experience of driving, and
Speaker 1: suddenly there's a deflating air bag and a strange smell
Speaker 1: of nitrates, But the actual deployment of the bag happens
Speaker 1: way too fast for a person to be conscious of it.
Speaker 1: It strikes me that this sudden disappearance of consciousness with
Speaker 1: no bad feelings or fear probably happens with victims of
Speaker 1: pyroclastic flow from volcanoes. This is a one thousand degree
Speaker 1: wall of hot rock and gas that travels faster than
Speaker 1: one hundred miles per hour, meaning that if you're in
Speaker 1: your house and you don't know that this pyroclastic flow
Speaker 1: is coming, you're going to be consumed before your neural
Speaker 1: signals ever come together to form the conclusion that something
Speaker 1: is amiss and just came crashing through your wall. In
Speaker 1: this case, the speed of the danger outstrips the speed
Speaker 1: of the neural signals, and it's the same with a
Speaker 1: nuclear blast if that comes without warning. Nuclear blasts have
Speaker 1: a series of events. There's a flash of light and
Speaker 1: a pulsive thermal energy heat, and a pulse of nuclear radiation,
Speaker 1: and these all happen at the speed of light. So
Speaker 1: if you see a bomb descending and you realize you're
Speaker 1: going to be quite close to the point blank detonation,
Speaker 1: there's actually no reason to panic, because, just like the
Speaker 1: drivers who never witnessed the airbag's deploy you won't witness
Speaker 1: the bomb burst. Our evolution took place over millions of
Speaker 1: years in which this delay of a few hundred milliseconds
Speaker 1: was plenty fast to react to humans or horses or
Speaker 1: hippopotamia coming to attack you. This window might not have
Speaker 1: been fast enough for a pouncing lion, but our existence
Speaker 1: here allows us to conclude that the signals were fast
Speaker 1: enough that our species was not selected out. But we
Speaker 1: didn't evolve in a world with racing metal cars and
Speaker 1: bullets and nuclear bombs. Under these conditions, the speed of
Speaker 1: the events outstrips the leisurely neural signals. So if you've
Speaker 1: been having a tough day, take this all as a
Speaker 1: piece of good news, which is that your consciousness is
Speaker 1: so slow that you might completely miss out on the
Speaker 1: final thing that brings your story to a close. Like
Speaker 1: Tony Soprano, the song will be playing on the jukebox,
Speaker 1: and then it's not, and the horror that everyone else
Speaker 1: sees is simply not experienced by you. This tardiness of
Speaker 1: consciousness is why I have no fear of dying by
Speaker 1: something sudden, a piano falling on me, or an explosion
Speaker 1: or an unseen hit man. And this is why Boeing's
Speaker 1: council argued the unpopular but presumably correct position that the
Speaker 1: moment of impact at hundreds of miles per hour was
Speaker 1: too fast for any conscious awareness that an impact had
Speaker 1: ever occurred, and therefore, while Boeing's attorneys paid damages for
Speaker 1: all other aspects of the tragedy, they argued against that one.
Speaker 1: Perhaps there's no reason to fear dying from a piano
Speaker 1: falling on your head, because, as your consciousness won't yet
Speaker 1: have caught up, you'll simply be there enjoying a nice
Speaker 1: cup of coffee on a beautiful day, noticing the nice
Speaker 1: clouds in the sky, birds chirping, thinking about something you
Speaker 1: need to remember to put on your to do list,
Speaker 1: and then the footage will suddenly end. To find out
Speaker 1: more and to share your thoughts, head to eagleman dot com,
Speaker 1: slash podcasts, and you can also watch full episodes of
Speaker 1: Inner Cosmos on YouTube at inner Cosmospod. Subscribe to see
Speaker 1: new episodes every week until next time. I'm David Eagleman,
Speaker 1: signing out from the Inner