WEBVTT - Ep13 "Will you perceive the event that kills you?" 0:00:05.200 --> 0:00:08.280 How far in the past do you live? Why are 0:00:08.400 --> 0:00:12.039 live television shows not actually live? And what does any 0:00:12.119 --> 0:00:14.680 of this have to do with nuclear bombs or car 0:00:14.760 --> 0:00:19.000 accidents where the Boeing airlines crash in Ethiopia or volcanoes 0:00:19.560 --> 0:00:26.360 or the last episode of The Sopranos. Welcome to Inner 0:00:26.440 --> 0:00:30.200 Cosmos with me David Eagleman. I'm a neuroscientist and an 0:00:30.280 --> 0:00:33.800 author at Stanford University, and I've always been obsessed with 0:00:33.920 --> 0:00:37.320 how we perceive time. In this episode, I'm going to 0:00:37.360 --> 0:00:41.040 dive into an issue about time perception that's always intrigued me, 0:00:41.479 --> 0:00:44.760 which is how long do we have to wait before 0:00:44.800 --> 0:00:48.960 we have a conscious perception of something that just happened 0:00:49.000 --> 0:00:52.400 in the world. And that leads to a very wild question, 0:00:53.240 --> 0:01:05.880 will you perceive the event that kills you? So imagine 0:01:05.880 --> 0:01:09.920 that you're walking down the sidewalk and you're enjoying the sunshine, 0:01:09.959 --> 0:01:13.319 and you're sipping your coffee from a paper cup and 0:01:13.400 --> 0:01:17.080 watching two dogs wrestling around and having fun in the distance, 0:01:17.800 --> 0:01:22.240 and suddenly, from a crane perched ten stories in the air, 0:01:23.000 --> 0:01:26.440 a piano falls and lands right on top of you. 0:01:27.319 --> 0:01:30.279 The question we want to dive into today is will 0:01:30.319 --> 0:01:35.840 you be aware of that final moment, or while you 0:01:36.160 --> 0:01:39.280 feel you're happily watching the dogs and sipping the coffee, 0:01:39.840 --> 0:01:44.520 will the footage just end? Now this is not an 0:01:44.560 --> 0:01:48.080 idle question. It's one that allows us to dig deep 0:01:48.120 --> 0:01:51.120 into what happens in the brain, and it's one that 0:01:51.280 --> 0:01:55.760 sometimes gets wrestled with in courts of law. So let's 0:01:55.800 --> 0:01:59.680 start this story in twenty seventeen when the United States 0:02:00.000 --> 0:02:03.520 it proved a new generation of the Boeing seven thirty 0:02:03.520 --> 0:02:08.080 seven airplane. This was called the Boeing seven thirty seven Max, 0:02:08.639 --> 0:02:12.800 and it was a great evolution for this leading airliner company, 0:02:13.160 --> 0:02:16.640 and it immediately produced hundreds of orders that came pouring 0:02:16.680 --> 0:02:19.760 in from around the world. So everything looked great. But 0:02:19.880 --> 0:02:24.240 then in October of twenty eighteen, a seven thirty seven 0:02:24.360 --> 0:02:28.480 Max took off from Jakarta on its way to Indonesia, 0:02:28.560 --> 0:02:32.560 and thirteen minutes after takeoff, it crashed into the Java 0:02:32.680 --> 0:02:35.560 Sea and it killed all one hundred and eighty nine 0:02:35.600 --> 0:02:40.160 people on board. So that immediately triggered investigations into whether 0:02:40.240 --> 0:02:44.000 something about this new airplane design had anything to do 0:02:44.080 --> 0:02:49.040 with the crash, and those investigations uncovered a serious issue. 0:02:49.400 --> 0:02:52.880 It turns out that some previous seven thirty seven Max 0:02:52.919 --> 0:02:56.520 flights had had serious problems. There hadn't been a crash, 0:02:56.560 --> 0:03:00.840 but nonetheless the passengers had been traumatized. And the problems 0:03:00.880 --> 0:03:03.359 had to do with the failure of a sensor that 0:03:03.400 --> 0:03:06.440 detects the angle of attack, which is just the angle 0:03:06.480 --> 0:03:09.680 between the wing and the wind, and that mattered because 0:03:09.720 --> 0:03:13.080 it affects the amount of lift that the airplane gets. So, 0:03:13.280 --> 0:03:16.480 without going into details, it surfaced that there was this 0:03:16.680 --> 0:03:20.480 inherent design flaw in the seven thirty seven Maxes that 0:03:20.560 --> 0:03:24.880 made these planes really hard to control in some circumstances 0:03:24.919 --> 0:03:29.760 and really dangerous. So the Federal Aviation Administration and Boeing 0:03:30.120 --> 0:03:33.920 moved quickly to give out warnings and training advisories to 0:03:34.000 --> 0:03:37.120 all the operators of the seven thirty seven Max series 0:03:37.560 --> 0:03:42.000 to avoid this kind of problem. But before these got implemented, 0:03:42.520 --> 0:03:47.760 something awful happened. In March of twenty nineteen, Ethiopian Airlines 0:03:47.800 --> 0:03:52.040 Flight three h two crashed because of this exact same problem, 0:03:52.400 --> 0:03:56.040 and that crash instantly killed all one hundred and fifty 0:03:56.040 --> 0:03:59.040 seven people on board, and that led to an immediate 0:03:59.080 --> 0:04:03.600 grounding of all seven thirty seven Max airplanes around the planet. 0:04:04.000 --> 0:04:07.360 Now there are hundreds of angles to the enormous legal 0:04:07.480 --> 0:04:11.760 case around the crash of the Ethiopian Airlines flight, including 0:04:11.880 --> 0:04:15.080 negligence and collusion. But I'm going to zoom in on 0:04:15.120 --> 0:04:17.560 a part of the lawsuit that's currently in the courts, 0:04:18.160 --> 0:04:20.880 and that part of the legal argument comes down to 0:04:20.960 --> 0:04:25.839 millions of dollars and the final half second, and that's 0:04:26.000 --> 0:04:32.080 where neuroscience unexpectedly intersects with aviation. In the aftermath of 0:04:32.120 --> 0:04:35.719 the crash, Boeing executives met with the victims' families and 0:04:35.760 --> 0:04:39.240 they pledged a one hundred million dollar fund for the families, 0:04:39.640 --> 0:04:42.960 separate from any lawsuit. And then Boeing settled for two 0:04:43.000 --> 0:04:45.840 and a half billion with the Justice Department, and they 0:04:45.839 --> 0:04:49.760 agreed to pay five hundred million more to the victim's beneficiaries. 0:04:50.160 --> 0:04:53.960 Then they also paid other fines for alleged misleading statements 0:04:54.000 --> 0:04:59.120 and so on. But Boeing's attorneys argued that they shouldn't 0:04:59.120 --> 0:05:03.400 have to pay out any money for pain and suffering. Now, 0:05:03.480 --> 0:05:05.760 let's be clear on what the legal argument is here. 0:05:06.160 --> 0:05:09.760 In legal terms, while the plane was tilting and heading 0:05:09.800 --> 0:05:15.280 towards the ground, the nausea and terrible fear falls into 0:05:15.320 --> 0:05:19.400 a legal category of mental anguish. But that's a different 0:05:19.520 --> 0:05:23.400 category of damages than pain and suffering, which is what 0:05:23.520 --> 0:05:27.240 happens between a physical injury and the time of death. 0:05:28.160 --> 0:05:30.160 Now this is grim stuff, but it's the kind of 0:05:30.200 --> 0:05:33.760 analysis that comes up in courtrooms all the time. Imagine 0:05:33.800 --> 0:05:38.160 that there's a factory and there's a poorly braced machine 0:05:38.240 --> 0:05:41.320 and it falls on a worker, and that person ends 0:05:41.400 --> 0:05:45.120 up pinned for hours and bleeding out, and they're conscious 0:05:45.160 --> 0:05:48.120 the whole time of what is happening to them, and 0:05:48.160 --> 0:05:51.159 they pass away. Now, that would fall under the legal 0:05:51.200 --> 0:05:56.440 category of pain and suffering. That category of damages starts 0:05:56.440 --> 0:05:59.680 at the moment of physical injury and runs until the 0:05:59.720 --> 0:06:04.120 time of death. But Boeing's attorneys argued that while there 0:06:04.200 --> 0:06:09.120 certainly was mental anguish during the six minute roller coaster ride, 0:06:09.160 --> 0:06:11.679 there was no pain in suffering that could be argued 0:06:11.720 --> 0:06:15.359 in this case. Why because the planes impact with the 0:06:15.400 --> 0:06:20.479 ground caused instantaneous death. What Boeing said is that the 0:06:20.600 --> 0:06:25.200 victims died painlessly because the airplane crashed into the ground 0:06:25.279 --> 0:06:30.000 so fast that their brains didn't have time to process 0:06:30.400 --> 0:06:35.039 pain signals. In other words, there was no time between 0:06:35.200 --> 0:06:39.640 injury and death. Just to be clear, Boeing's attorneys aren't 0:06:39.800 --> 0:06:43.760 arguing that the families can't recover massive damages in the lawsuit. 0:06:43.920 --> 0:06:47.840 They're just talking about this specific category of pain and suffering, 0:06:48.279 --> 0:06:52.160 and this isn't an unusual argument in wrongful death cases 0:06:52.279 --> 0:06:55.960 like plane crashes and car accidents, to argue in a 0:06:56.000 --> 0:06:59.080 courtroom about what someone's experience would have been like in 0:06:59.080 --> 0:07:03.120 their final moments, and therefore whether they experienced any pain 0:07:03.160 --> 0:07:05.880 and suffering. It comes down to the issue of whether 0:07:05.960 --> 0:07:10.040 the passengers were aware that the plane hit the ground, 0:07:10.440 --> 0:07:13.239 and this boils down to a question that can only 0:07:13.280 --> 0:07:16.920 be addressed by neuroscience. Time is one of the most 0:07:16.920 --> 0:07:20.600 important elements in our lives, but how we perceive time 0:07:21.200 --> 0:07:24.400 is one of the least understood. So I've devoted a 0:07:24.560 --> 0:07:27.000 large part of my career to try to figure out 0:07:27.120 --> 0:07:31.520 our experience of time, and the lesson that surfaces is 0:07:31.560 --> 0:07:35.040 that our perceptual experience is the result of lots of 0:07:35.120 --> 0:07:38.640 computation in the brain and it doesn't necessarily map on 0:07:39.200 --> 0:07:43.160 to what reality actually is. Now. In a different episode, 0:07:43.200 --> 0:07:46.000 I talked about time seeming to run in slow motion. 0:07:46.560 --> 0:07:49.360 Many people have had this impression when they're in a 0:07:49.440 --> 0:07:54.000 life threatening situation that an event seemed to last longer 0:07:54.040 --> 0:07:56.880 than normal. And in that episode, I told the story 0:07:56.920 --> 0:07:59.440 about when I was eight years old and fell off 0:07:59.440 --> 0:08:02.360 of the roof of a house inner construction and time 0:08:02.480 --> 0:08:05.720 seemed to run in slow motion, and how that eventually 0:08:05.800 --> 0:08:08.960 led to me becoming a neuroscientist because I grew so 0:08:09.240 --> 0:08:14.280 fascinated with this almost totally unexplored area. In this episode, 0:08:14.320 --> 0:08:16.560 I'm going to take you on a totally different path 0:08:16.840 --> 0:08:20.400 through time perception, and we're going to see some mind 0:08:20.520 --> 0:08:39.920 bending surprises along the way. Now, to tackle something as 0:08:40.000 --> 0:08:43.920 big and mysterious as time, it helps begin with something 0:08:44.120 --> 0:08:47.440 very simple, and many years ago I stumbled on a 0:08:47.800 --> 0:08:51.520 simple visual illusion that ended up opening big doors for 0:08:51.640 --> 0:08:55.360 my understanding of time. And that illusion was first noticed 0:08:55.360 --> 0:08:59.280 in the nineteen twenties. It's called the flash lag illusion. 0:08:59.640 --> 0:09:03.040 And here's how it goes. Imagine you're looking out your 0:09:03.040 --> 0:09:06.400 window and you see a bicyclist zipping along the road 0:09:06.440 --> 0:09:09.080 in front of your house, going from the left side 0:09:09.120 --> 0:09:11.840 to the right side, and as they're going by, a 0:09:11.960 --> 0:09:16.559 bright light flashes very briefly on their helmet. Flash. That's 0:09:16.600 --> 0:09:19.200 all I need you to picture. Bike moves along light 0:09:19.240 --> 0:09:22.280 flashes on their helmet. So what hits your eye is 0:09:22.320 --> 0:09:25.480 the bike and the flash in the same location, but 0:09:25.520 --> 0:09:30.280 what you consciously perceive is something different. The way it 0:09:30.320 --> 0:09:33.559 looks to you is that the bike was some distance 0:09:33.840 --> 0:09:36.760 ahead of the flash. It doesn't look like they're in 0:09:36.800 --> 0:09:40.400 the same spot. Now, this flash lag illusion is very 0:09:40.440 --> 0:09:43.280 easy to demonstrate and to quantify, and you can see 0:09:43.280 --> 0:09:47.440 demos of this at Eagleman dot com Slash podcast. But 0:09:47.480 --> 0:09:51.280 the question is why does this happen? So what had 0:09:51.280 --> 0:09:54.360 been proposed in the literature is that maybe what's happening 0:09:54.520 --> 0:09:58.960 is your visual system watches the bicyclist, but it doesn't 0:09:59.200 --> 0:10:01.640 see the bike where it is right now, but instead 0:10:01.720 --> 0:10:04.400 your brain is guessing where the bike will be in 0:10:04.440 --> 0:10:08.400 the next moment. Your brain is making a prediction, and 0:10:08.440 --> 0:10:11.280 that's what you see is this predicted position a little 0:10:11.320 --> 0:10:14.280 bit ahead. But your brain doesn't have that luxury with 0:10:14.360 --> 0:10:17.000 the flash because it didn't know that was about to happen, 0:10:17.320 --> 0:10:20.040 and so it can't make any predictions there. And so 0:10:20.200 --> 0:10:23.839 the bike looks farther ahead to the right in this case, 0:10:23.880 --> 0:10:27.840 and the flash appears exactly where it happened. Now, I 0:10:27.880 --> 0:10:30.679 had some reasons to doubt that framework. So I set 0:10:30.760 --> 0:10:35.359 up a very simple experiment which I presented to test participants. 0:10:35.920 --> 0:10:38.720 Imagine on the screen you're watching the bike moving to 0:10:38.760 --> 0:10:41.640 the right, and I have a flash appear for just 0:10:41.720 --> 0:10:44.880 one frame, and it's perfectly lined up with the bike. Now, 0:10:44.880 --> 0:10:47.760 that's what gives you the flashlight illusion. But now I'm 0:10:47.800 --> 0:10:51.800 going to do one of three things at random after 0:10:51.840 --> 0:10:55.640 the flash is over. Either the bike keeps going, or 0:10:55.720 --> 0:11:00.720 the bike instantly stops, or the bike reverses direction. The 0:11:00.800 --> 0:11:03.560 key thing to note here is that everything up to 0:11:03.679 --> 0:11:07.559 and including the flash is identical, and all I'm doing 0:11:07.640 --> 0:11:11.679 is changing what happens in the future of the flash. 0:11:11.720 --> 0:11:14.720 So if prediction is happening, if your brain is just 0:11:14.920 --> 0:11:18.360 guessing ahead where the moving bike is, then of course 0:11:18.360 --> 0:11:21.120 we'll expect to see the same thing every time, which 0:11:21.160 --> 0:11:23.880 is that the bike should be ahead of the flash 0:11:23.920 --> 0:11:27.280 to the right, because it shouldn't matter what happens after 0:11:27.320 --> 0:11:31.160 the flash is already gone. But here's what actually happens. 0:11:31.760 --> 0:11:34.200 If the bike keeps going, it looks like it's ahead 0:11:34.200 --> 0:11:37.840 of the flash on the right, as expected. But if 0:11:37.880 --> 0:11:41.480 the bike stops instantly in the frame after the flash, 0:11:41.600 --> 0:11:44.160 it looks like the flash was on the helmet, there's 0:11:44.200 --> 0:11:48.760 no more illusion. And if the bike reverses its direction 0:11:49.040 --> 0:11:52.559 immediately after the flash, then it looks like the flash 0:11:52.679 --> 0:11:55.640 is off the helmet. In the other direction, the bike 0:11:55.720 --> 0:11:59.440 is off to the left now instead of to the right. Now. 0:11:59.480 --> 0:12:03.120 Why is that's such a weird result. It's so weird 0:12:03.280 --> 0:12:06.840 because I'm asking you what you see at the moment 0:12:06.880 --> 0:12:11.640 of the flash, and your answer depends on what happens 0:12:11.760 --> 0:12:15.520 in the future of the flash. And remember, these conditions 0:12:15.559 --> 0:12:18.600 are randomly interleaved, so you can't know what's actually going 0:12:18.679 --> 0:12:21.560 to happen on any given trial. So there's only two 0:12:21.600 --> 0:12:27.000 possibilities here. Either my test subjects were clairvoyantly seeing into 0:12:27.000 --> 0:12:29.960 the future, which I don't think is happening, or the 0:12:30.080 --> 0:12:34.640 perception that we attribute to some moment in time actually 0:12:34.720 --> 0:12:39.040 depends on what happens next. In other words, what we 0:12:39.080 --> 0:12:42.040 think happen in some moment depends on what happens after 0:12:42.080 --> 0:12:45.080 that moment. Now, this is a wild finding because it 0:12:45.200 --> 0:12:49.000 shows right away that the brain is not using prediction 0:12:49.320 --> 0:12:53.800 guessing ahead. Instead, it's something more like filling in behind. 0:12:54.480 --> 0:12:59.000 The key is that after the flash, your brain continues 0:12:59.040 --> 0:13:03.480 to collect up in information and it retrospectively says what 0:13:03.679 --> 0:13:07.240 it thinks it saw. Nothing is moving backwards in time. 0:13:07.520 --> 0:13:09.760 The correct way to think about this is to think 0:13:09.800 --> 0:13:13.720 about two timelines. There's time in the real world and 0:13:13.760 --> 0:13:17.080 there's time in your head. This is physical time and 0:13:17.200 --> 0:13:20.959 subjective time. And the timeline in your head is simply 0:13:21.320 --> 0:13:25.800 shifted later. It's a delayed version of what is happening 0:13:25.880 --> 0:13:28.640 in the real world. And this is because it takes 0:13:28.840 --> 0:13:32.360 time for signals to move around in the brain and 0:13:32.520 --> 0:13:36.400 get processed. So by the time the information from the 0:13:36.520 --> 0:13:41.720 flash gets fully through the machinery, new information about the 0:13:41.760 --> 0:13:45.079 movement of the bike has been streaming in. So by 0:13:45.120 --> 0:13:48.959 the time you become consciously aware of the flash, your 0:13:49.000 --> 0:13:53.800 brain has incorporated some information that happened after the flash. 0:13:54.080 --> 0:13:56.640 So I published this in the journal Science, and I 0:13:56.720 --> 0:14:01.040 called this phenomenon postdiction as opposed to prediction, and it 0:14:01.080 --> 0:14:03.800 actually became the most highly cited paper of my career 0:14:03.880 --> 0:14:07.560 so far because what it surfaces, in a very simple way, 0:14:08.080 --> 0:14:11.640 is a fundamental feature of our perception, which is that 0:14:11.679 --> 0:14:16.320 we live in the past. The brain collects information and 0:14:16.360 --> 0:14:20.240 that flows around and eventually comes to a conclusion and 0:14:20.280 --> 0:14:23.400 gives you a story of what happened in the world 0:14:23.400 --> 0:14:27.120 out there, and then we think, oh, that's what's happening 0:14:27.200 --> 0:14:30.320 right now. So when I say we're living in the past, 0:14:30.480 --> 0:14:33.280 I mean that by the time we think the moment 0:14:33.680 --> 0:14:38.920 now has occurred, it's already happened. Remember that signals in 0:14:38.960 --> 0:14:43.880 the brain move very slowly. In the cerebral cortex, which 0:14:43.920 --> 0:14:47.240 is the wrinkly outer covering of the brain, most signals 0:14:47.280 --> 0:14:51.320 are traveling around at one meter per second, which is 0:14:51.480 --> 0:14:56.320 three hundred million times slower than signals in fiber optic cables. 0:14:56.760 --> 0:14:59.760 So your brain has a challenge, which is that it's 0:14:59.760 --> 0:15:03.080 true trying to understand what's going on in the outside world. 0:15:03.600 --> 0:15:06.640 But it's big and it's made of billions of cells, 0:15:07.080 --> 0:15:10.640 and so its only good solution is to wait until 0:15:10.720 --> 0:15:14.160 all the signals have been collected up and compiled. It 0:15:14.240 --> 0:15:17.840 gathers the signals from the various senses, and once all 0:15:17.880 --> 0:15:23.120 that information has arrived, your brain develops a conscious narrative 0:15:23.360 --> 0:15:27.560 about what just happened. And the consequence is that your 0:15:27.680 --> 0:15:32.960 conscious mind lives behind reality. When I clap my hands 0:15:33.000 --> 0:15:36.640 together and we think the moment now is occurring, we're wrong. 0:15:36.760 --> 0:15:39.160 It already happens. Some time ago. Our brains had to 0:15:39.200 --> 0:15:43.200 collect the information from the visual system, the auditory system 0:15:43.680 --> 0:15:47.320 process that, stitch it all together and serve up a story, 0:15:47.360 --> 0:15:49.680 and then you say, oh, I just heard a clap. 0:15:50.400 --> 0:15:54.440 The consequence is that your perception of the world is 0:15:54.480 --> 0:15:57.960 something like the airing of a live television show like 0:15:58.040 --> 0:16:02.240 Saturday Night Live, which is not actually live, but it's 0:16:02.360 --> 0:16:06.800 aired with a delay in case someone cusses or falls down, 0:16:06.920 --> 0:16:10.280 or there's a wardrobe mishap, and so it goes with 0:16:10.400 --> 0:16:14.760 your consciousness. It is delayed by a small window while 0:16:14.800 --> 0:16:19.200 your brain puts together its story. What you perceive is 0:16:19.240 --> 0:16:23.600 a delayed version of reality. For all you know, this 0:16:23.720 --> 0:16:26.760 podcast is already over. Okay, not that far in the past, 0:16:27.040 --> 0:16:30.920 but how far in the past are we well in 0:16:30.960 --> 0:16:33.160 the flash lag effect, I was able to show that 0:16:33.200 --> 0:16:36.240 we were about a tenth of a second behind what 0:16:36.360 --> 0:16:39.280 was happening out there, one hundred milliseconds. But that was 0:16:39.320 --> 0:16:42.800 measured from experiments I did in the visual system. And 0:16:42.880 --> 0:16:45.720 for a unified perception of the world with all its 0:16:45.720 --> 0:16:48.720 sights and sounds and textures, you need to wait for 0:16:48.880 --> 0:16:52.080 all the information to stream in from all of the senses. 0:16:52.600 --> 0:16:55.240 And that means that if your brain wants to wait 0:16:55.760 --> 0:16:59.200 to collect up all the information before putting together a 0:16:59.240 --> 0:17:02.560 story of what happened, it needs to wait for the 0:17:02.680 --> 0:17:07.320 slowest information, which is from your toes. That information has 0:17:07.400 --> 0:17:09.119 to climb all the way up the nerves and your 0:17:09.200 --> 0:17:11.480 legs and then up the entire spinal cord all the 0:17:11.480 --> 0:17:15.080 way to your brain. And although the nerves that carry 0:17:15.119 --> 0:17:18.679 touch information are fast compared to some other kinds of nerves, 0:17:18.960 --> 0:17:23.280 they're super slow compared to say, the speed of signals 0:17:23.320 --> 0:17:25.919 in your computer, and so the whole thing takes more 0:17:26.000 --> 0:17:29.200 than one hundred milliseconds. And what I realized was that 0:17:29.280 --> 0:17:32.720 if your brain wants a unified perception of what just 0:17:32.840 --> 0:17:36.120 happened in the world, rather than different pieces streaming at 0:17:36.160 --> 0:17:39.560 different times, it has no choice but to wait for 0:17:39.760 --> 0:17:43.480 all that information to arrive. And one way to demonstrate 0:17:43.520 --> 0:17:46.840 this is if I touch your nose and your toe 0:17:46.880 --> 0:17:50.200 at the same time, you will feel that as simultaneous. 0:17:50.520 --> 0:17:53.000 It's not like you feel the signal from your nose 0:17:53.480 --> 0:17:56.240 and then you feel it later from your toe, even 0:17:56.280 --> 0:17:58.480 though the signal from your nose gets to your brain 0:17:58.680 --> 0:18:01.639 much more quickly. So the question is does your brain 0:18:02.320 --> 0:18:05.680 capture the information from the nose and then say, Okay, cool, 0:18:05.720 --> 0:18:08.600 I've got that, but I'm not going to perceive anything 0:18:08.680 --> 0:18:12.879 yet because something else might be coming up the pipeline. Yes, 0:18:13.080 --> 0:18:16.439 I think that's actually what happens. And because the brain 0:18:16.480 --> 0:18:20.120 has to wait for this slow information to arrive, this 0:18:20.240 --> 0:18:25.040 leads to the bizarre but testable prediction that tall people 0:18:25.720 --> 0:18:29.840 live further in the past than short people. So I 0:18:29.960 --> 0:18:33.560 mentioned my prediction once on a live interview on NPR, 0:18:33.600 --> 0:18:35.639 and then I drove back to my lab and I 0:18:35.680 --> 0:18:38.640 opened my email, and I saw that I had received 0:18:39.000 --> 0:18:43.280 dozens of emails from people who said, I'm short, and 0:18:43.359 --> 0:18:46.159 I really appreciate what you said. But let's get back 0:18:46.200 --> 0:18:50.360 to this question of how far behind reality does your 0:18:50.440 --> 0:18:56.000 consciousness lag. In the nineteen seventies, a neuroscientist named Benjamin 0:18:56.000 --> 0:18:59.800 Libbitt did some studies with people who were undergoing neuros, 0:19:00.800 --> 0:19:04.680 and those studies suggested that we lag as much as 0:19:04.920 --> 0:19:08.359 five hundred milliseconds half a second. I'm not going to 0:19:08.440 --> 0:19:10.840 go into the details of his experiment here, but I've 0:19:10.880 --> 0:19:14.600 linked the research on the podcast website. So Libbett's claim 0:19:14.680 --> 0:19:17.000 was that we are half a second in the past, 0:19:17.680 --> 0:19:21.199 and it's worth noting that it might be impossible for 0:19:21.320 --> 0:19:25.000 us to measure the moment of onset of conscious experience, 0:19:25.440 --> 0:19:27.800 so the exact time delay is very hard to know 0:19:27.920 --> 0:19:30.920 for sure, but for now, let's call it about half 0:19:30.960 --> 0:19:34.200 a second in the past. And this happens because the 0:19:34.200 --> 0:19:37.399 brain needs to collect all the signals from the eyes 0:19:37.440 --> 0:19:39.760 and the ears and the skin, and those need to 0:19:39.840 --> 0:19:43.760 travel along their respective nerves and enter the brain in 0:19:43.800 --> 0:19:46.200 the place that they come in in the primary sensory 0:19:46.200 --> 0:19:49.359 cortex for each sense, and then move to the secondary 0:19:49.400 --> 0:19:53.000 sensory cortex and tertiary, and the signals splash out into 0:19:53.080 --> 0:19:57.280 multimodal areas, and everything needs to get stitched together into 0:19:57.320 --> 0:20:01.240 a story of what just happened. And by the time 0:20:01.320 --> 0:20:05.560 this whole process completes itself, the event itself in the 0:20:05.600 --> 0:20:24.000 world is already long gone. Now the more I study this, 0:20:24.160 --> 0:20:27.880 the more I realized that this strange fact has an 0:20:27.960 --> 0:20:33.760 interesting and unappreciated consequence. You probably won't perceive the event 0:20:34.000 --> 0:20:38.040 that kills you, at least if that event happens suddenly. 0:20:38.600 --> 0:20:41.240 So let's return to this scenario of you walking down 0:20:41.280 --> 0:20:44.280 the street and joining your coffee and suddenly the piano 0:20:44.359 --> 0:20:47.800 falls on you. That would be so terrible, right, But 0:20:47.880 --> 0:20:51.000 what we've just seen is that it takes time for 0:20:51.080 --> 0:20:55.800 signals to come together to form a conscious story. So 0:20:55.880 --> 0:21:00.080 that means that if your brain gets damaged before the 0:21:00.119 --> 0:21:05.040 signals come together, then it says though the footage suddenly ends. 0:21:05.760 --> 0:21:07.840 And this would be true not only for our pianos, 0:21:07.880 --> 0:21:11.560 but for any unexpected event like a bullet or a 0:21:11.600 --> 0:21:15.720 bomb explosion. The damage to the brain would happen much 0:21:15.800 --> 0:21:20.240 faster than the time it takes to process the signals 0:21:20.520 --> 0:21:24.359 and come to a conscious conclusion. Now, I've been studying 0:21:24.359 --> 0:21:26.560 this in my lab for many years, and so I 0:21:26.640 --> 0:21:30.040 was really amazed when I saw the great author Cormick 0:21:30.119 --> 0:21:35.440 McCarthy point to this in his post apocalyptic novel The Road. 0:21:36.560 --> 0:21:39.640 So at one point in the novel, the main character 0:21:40.240 --> 0:21:42.640 levels his pistol on a bad guy who was trying 0:21:42.680 --> 0:21:46.520 to attack him, and the bad guy says, quote, you 0:21:46.600 --> 0:21:50.840 won't shoot My companions will hear the shot, And our 0:21:50.920 --> 0:21:55.760 hero says, yes, they will, but you won't. And the 0:21:55.800 --> 0:21:58.920 bad guy says, how do you figure that? And our 0:21:58.960 --> 0:22:03.280 hero says, because the bullet travels faster than the sound, 0:22:03.760 --> 0:22:06.920 it'll be in your brain before you can hear it. 0:22:07.480 --> 0:22:10.399 To hear it, you'll need a frontal lobe and things 0:22:10.400 --> 0:22:14.120 with names like colliculus and temporal gyrus, and you won't 0:22:14.160 --> 0:22:18.439 have them anymore. They'll just be soup. In other words, 0:22:18.440 --> 0:22:21.040 what McCarthy was pointing out is the same issue, which 0:22:21.080 --> 0:22:25.240 is that you need your brain to perceive. No brain, 0:22:25.960 --> 0:22:30.080 no perception. Now, one of the most popular shows in 0:22:30.119 --> 0:22:34.760 television history was The Sopranos, and if you didn't see it, 0:22:34.760 --> 0:22:37.439 it was an intimate story of a mafia family in 0:22:37.480 --> 0:22:39.679 New Jersey, and it was told over eight years. It 0:22:39.760 --> 0:22:43.720 had tens of millions of dedicated fans, and so when 0:22:43.760 --> 0:22:47.399 the finale to the whole show finally arrived, everyone was 0:22:47.440 --> 0:22:50.240 tuned in to see how the show would end. The 0:22:50.600 --> 0:22:55.000 series centers on Tony Soprano, this mafia head in New Jersey, 0:22:55.440 --> 0:22:57.800 and the thing about Tony Soprano is that he's always 0:22:58.320 --> 0:23:01.720 struggling to balance his fan family life and his role 0:23:01.840 --> 0:23:04.879 as a mob boss. So he has panic attacks and 0:23:04.920 --> 0:23:07.600 we get to see him in therapy sessions with his 0:23:07.640 --> 0:23:10.840 psychiatrist throughout the series, and if you've never seen it, 0:23:11.240 --> 0:23:14.560 you can imagine there are life threatening complications all the 0:23:14.560 --> 0:23:18.520 time with other mobsters inside his family and outside, and 0:23:18.720 --> 0:23:23.720 specifically with the New York City based Lupertazzi family, which 0:23:23.760 --> 0:23:26.800 had been working to take down the Soprano family by 0:23:27.080 --> 0:23:30.520 decapitating them, in other words, by taking out their leadership 0:23:31.240 --> 0:23:34.960 some of Tony's family and collaborators. They were gunned down, 0:23:35.080 --> 0:23:37.879 one was put in a coma, and shots were taken 0:23:37.920 --> 0:23:43.359 to Tony. But now in the final episode, things seem 0:23:43.440 --> 0:23:47.400 to have calmed down. Tony seems to be in control 0:23:47.600 --> 0:23:51.400 of his New Jersey empire, and yet as the episode 0:23:51.440 --> 0:23:54.960 is coming to an end, something seems just slightly off. 0:23:55.320 --> 0:23:58.560 Tony is sitting in a diner eating onion rings and 0:23:58.600 --> 0:24:02.639 listening to Don't Stop Believing by Journey on the jukebox. 0:24:03.480 --> 0:24:06.520 The camera passes by people here and there. It's hard 0:24:06.560 --> 0:24:08.880 to tell if anyone seems out of place, like when 0:24:08.880 --> 0:24:12.760 the camera follows one seemingly random man who goes into 0:24:12.800 --> 0:24:15.800 the bathroom behind where Tony is sitting, and we see 0:24:15.840 --> 0:24:20.040 Tony's daughter park across the street, and she runs across 0:24:20.080 --> 0:24:22.600 the street to join him, and we hear the bell 0:24:22.760 --> 0:24:25.880 on the door, which is presumably her entrance, and he 0:24:26.000 --> 0:24:30.480 looks up from his food, and then the video and 0:24:30.720 --> 0:24:35.320 audio cut to blackness and silence, So fans went into 0:24:35.320 --> 0:24:38.520 an uproar. What just happened to the show? Was there 0:24:38.520 --> 0:24:42.440 a broadcasting hiccup? Was this a technical problem with their television? 0:24:43.080 --> 0:24:47.520 But it wasn't. The show ends that way because we 0:24:47.680 --> 0:24:52.200 are in Tony's point of view, and suddenly there simply 0:24:52.560 --> 0:24:57.560 is no more point of view. The fragile circuits necessary 0:24:57.640 --> 0:25:01.600 for Tony's brain to construct a story have been wrecked 0:25:01.640 --> 0:25:06.000 by a bullet, and the damage happens before they've been 0:25:06.080 --> 0:25:09.960 able to stitch together a story about that last half 0:25:10.000 --> 0:25:13.560 second of his life. Now, this scene of Tony's death 0:25:13.600 --> 0:25:16.960 connected back to an earlier snippet of dialogue from two 0:25:17.000 --> 0:25:22.240 seasons earlier, in which Bobby Bachlieri says to Tony, quote, 0:25:22.920 --> 0:25:26.080 you probably don't even hear it when it happens. Right, 0:25:27.280 --> 0:25:30.439 because of the slow propagation of signals in the nervous 0:25:30.480 --> 0:25:34.520 system and the slow stitching together of consciousness, you might 0:25:34.720 --> 0:25:38.080 never even be aware that a gun fired, or that 0:25:38.119 --> 0:25:41.480 a bomb exploded, or that a truck just crashed through 0:25:41.480 --> 0:25:44.720 the wall, or a jet engine fell on your head. 0:25:45.200 --> 0:25:49.439 One moment you're present and thinking, and the next moment, 0:25:49.920 --> 0:25:55.480 your machinery for thought is gone. The broadcast of consciousness 0:25:55.800 --> 0:26:02.920 just cuts way to appreciate the sluggishness of your perception 0:26:03.480 --> 0:26:06.359