WEBVTT - Ep1 rebroadcast "Does time really slow down when you're in fear for your life?" 0:00:04.680 --> 0:00:07.680 So you always hear people say things like I got 0:00:07.680 --> 0:00:10.360 in a car accident and the whole thing seemed to 0:00:10.360 --> 0:00:14.760 happen in slow motion. I saw the hood crumple and 0:00:14.800 --> 0:00:17.520 the rear view mirror fall off, and I was watching 0:00:17.600 --> 0:00:20.759 the other driver's expression. And it's the same thing with 0:00:20.840 --> 0:00:26.119 gunfights or skiing accidents or motorcycle crashes. But from a 0:00:26.200 --> 0:00:31.120 neuroscience perspective, is it true that time slows down? And 0:00:31.160 --> 0:00:34.200 how could you test that? And why does your drive 0:00:34.320 --> 0:00:36.239 to work on the first day seem to take a 0:00:36.240 --> 0:00:39.240 long time, but after a while it takes no time 0:00:39.280 --> 0:00:41.640 at all. And why do the years seem to go 0:00:41.680 --> 0:00:47.680 by faster as we get older? Welcome to inner Cosmos 0:00:47.760 --> 0:00:52.320 with me, David Eagleman. I'm a neuroscientist and an author 0:00:52.360 --> 0:00:57.480 at Stanford University, and I've spent my whole career studying 0:00:57.520 --> 0:01:03.920 the intersection between how the works and how we experienced life. 0:01:08.800 --> 0:01:11.840 The first time I experienced time slowing down, I was 0:01:12.000 --> 0:01:15.440 eight years old. It was a Saturday, and my brother 0:01:15.520 --> 0:01:18.280 and I left the house to find something to do, 0:01:19.000 --> 0:01:21.720 and on the way out the door, our father warned 0:01:21.800 --> 0:01:25.039 us not to go near the house under construction, and 0:01:25.080 --> 0:01:27.880 so we told him we wouldn't, and being children, we 0:01:27.920 --> 0:01:30.600 of course went straight to the house under construction. So 0:01:30.880 --> 0:01:34.440 we poked around like kids do, and eventually we found 0:01:34.440 --> 0:01:37.400 a ladder and we went up onto the roof, and 0:01:37.480 --> 0:01:40.720 from there one could enjoy a wonderful view of the 0:01:40.760 --> 0:01:45.200 mountains of Albuquerque, New Mexico. And my brother wandered off 0:01:45.240 --> 0:01:47.520 to explore some other part of the roof, and I 0:01:47.720 --> 0:01:51.919 stepped forward to stand at the edge. Now I didn't 0:01:52.000 --> 0:01:55.200 know what tar paper was. I didn't know that it 0:01:55.280 --> 0:01:59.000 was stiff and that it extended past the edge of 0:01:59.040 --> 0:02:02.440 the roof on a center construction. So when I thought 0:02:02.440 --> 0:02:04.920 I was stepping to the roof's edge, I was actually 0:02:04.960 --> 0:02:08.760 stepping on the tar paper, and I began to fall. 0:02:13.880 --> 0:02:18.600 As I fell, I thought about grabbing for the roof's edge, 0:02:18.639 --> 0:02:21.240 but some part of my brain recognized I was too 0:02:21.360 --> 0:02:25.720 late for that. So I found myself in a spread 0:02:25.760 --> 0:02:30.760 eagle position, looking way down to the red brick floor below, 0:02:32.040 --> 0:02:34.360 And as I fell towards what was likely to be 0:02:34.560 --> 0:02:39.360 my death, I was thinking calmly about how similar my 0:02:39.560 --> 0:02:43.320 fall was to that scene in Alice in Wonderland when 0:02:43.320 --> 0:02:47.440 she falls down the rabbit hole. It was totally calm 0:02:47.520 --> 0:02:51.360 and peaceful. I didn't have any fear or panic. I 0:02:51.400 --> 0:02:54.520 was just thinking about a moment from a children's story. 0:02:58.840 --> 0:03:01.200 So it won't surprise you that I lived. But it 0:03:01.240 --> 0:03:05.560 did surprise my parents and the emergency room physicians because 0:03:05.560 --> 0:03:08.840 I'd fallen twelve feet and landed on my face, on 0:03:08.960 --> 0:03:12.600 my nose, and I'd lost consciousness and a lot of blood, 0:03:12.600 --> 0:03:15.600 and I'd shattered all the cartilage in my nose. But 0:03:15.720 --> 0:03:19.440 what stayed with me wasn't anything about that or the pain. 0:03:19.560 --> 0:03:24.560 It was a fascination with what had happened. So fast 0:03:24.600 --> 0:03:27.680 forward seven years later, I'm in high school physics, and 0:03:27.760 --> 0:03:31.400 I learned the formula de equals one half at squared, 0:03:31.440 --> 0:03:34.640 and that allows me to calculate how long the fall took. 0:03:35.560 --> 0:03:39.200 And I realize the fall had only taken point six 0:03:39.240 --> 0:03:42.920 of a second. What that couldn't be right. It seemed 0:03:42.920 --> 0:03:46.480 to have taken so much longer. So fast forward some 0:03:46.480 --> 0:03:49.880 more years and I'd become a neuroscientist, and my graduate 0:03:49.920 --> 0:03:53.160 thesis was a large computational model of a chunk of 0:03:53.240 --> 0:03:56.200 brain tissue and the signaling that happens in there. But 0:03:56.320 --> 0:04:01.760 the experience of my falls mysteriously long, long duration never 0:04:01.920 --> 0:04:05.560 left me. So once I became faculty, I started looking 0:04:05.600 --> 0:04:09.840 into this and I started collecting stories from people. So 0:04:09.880 --> 0:04:12.600 I'm going to start with one from a police officer. 0:04:13.600 --> 0:04:17.800 So one morning, he got radioed that two suspects were 0:04:17.839 --> 0:04:21.520 heading his way in a police car chase and that 0:04:21.760 --> 0:04:24.599 he should position his car in the middle of the 0:04:24.680 --> 0:04:28.240 road to stop them. So he does that, and he 0:04:28.320 --> 0:04:30.919 sees the car coming in from the distance, and he 0:04:30.960 --> 0:04:33.640 stands in the middle of the street and raises his 0:04:33.720 --> 0:04:36.640 hand for them to stop, but they just keep coming, 0:04:36.960 --> 0:04:40.400 and they're coming right at him. So he draws his 0:04:40.440 --> 0:04:43.600 revolver and he points it at the driver with the 0:04:43.640 --> 0:04:46.799 intention of shooting him through the windshield. And the car 0:04:46.920 --> 0:04:50.360 is so close, and for him, it seemed like time 0:04:50.520 --> 0:04:56.080 went into slow motion. And here's how he reports his thoughts. Now, 0:04:56.080 --> 0:05:00.000 wait a second, these are three point fifty seven HaLow points, 0:05:00.520 --> 0:05:03.440 and they should go right through the glass. But since 0:05:03.480 --> 0:05:06.359 the glass is angled, what if it ricochets off the 0:05:06.400 --> 0:05:09.600 glass and kills someone on the second story of that 0:05:09.760 --> 0:05:13.200 house over there. Anyway, he suddenly realizes that the car 0:05:13.360 --> 0:05:16.400 is almost on top of him, so he jumps out 0:05:16.400 --> 0:05:19.480 of the way, and at the same motion he squeezes 0:05:19.520 --> 0:05:22.960 off around at the driver's door, bang, and as the 0:05:22.960 --> 0:05:26.760 car goes by, he then pulls off a second round bang, 0:05:27.240 --> 0:05:29.400 And then as the car is almost all the way 0:05:29.480 --> 0:05:32.440 past him, he feels his finger pull off the third 0:05:32.520 --> 0:05:36.719 shot bang, and he assumes that he'd fired at the 0:05:36.760 --> 0:05:40.760 rear window, but he noticed that the glass hadn't broken, 0:05:41.360 --> 0:05:44.440 and so he starts to worry that maybe he'd missed, 0:05:44.480 --> 0:05:48.800 and maybe he'd shot a bystander down the road, and 0:05:48.839 --> 0:05:52.159 so he immediately is thinking about how his career might 0:05:52.200 --> 0:05:56.120 be over. And so his partner comes running up to him, 0:05:56.360 --> 0:06:00.120 and in the conversation afterwards, he realizes that his partner 0:06:00.640 --> 0:06:05.440 had witnessed a very different event. His partner said that 0:06:05.480 --> 0:06:09.919 the entire incident from the car approaching to when it 0:06:10.000 --> 0:06:14.200 went by, took maybe all of three seconds. And his 0:06:14.320 --> 0:06:17.280 partner said that the three shots sound like bang by bang, 0:06:18.000 --> 0:06:21.640 but it didn't feel that way to the officer firing 0:06:21.680 --> 0:06:24.320 the shots. It seemed like he had taken a lot 0:06:24.360 --> 0:06:28.480 of time to think about ricocheting, about people sitting in 0:06:28.520 --> 0:06:31.400 their living rooms, about whether the shot had hit the 0:06:31.440 --> 0:06:35.200 back window, about whether the shot would possibly hit a 0:06:35.200 --> 0:06:38.160 guy in a bar or some distance away. And in 0:06:38.240 --> 0:06:44.000 his mind, the shots went bang bang bang, as though 0:06:44.080 --> 0:06:48.880 everything were happening at a much slower pace. So how 0:06:48.960 --> 0:06:52.160 is it that a bang bang bang from one guy 0:06:52.360 --> 0:06:55.040 is perceived by someone else's bang bang bang? How does 0:06:55.080 --> 0:06:58.520 that happen? Now, here's another story from a doctor who 0:06:58.560 --> 0:07:02.000 got in a motorcycle accident. So he's going forty five 0:07:02.040 --> 0:07:04.880 miles an hour down the road. A car pulls out 0:07:04.920 --> 0:07:09.080 of the driveway and he comes off his bike and 0:07:09.120 --> 0:07:13.240 he hits the road and he rolls four or five times, 0:07:13.880 --> 0:07:17.160 and time appears to slow down, and he feels like 0:07:18.040 --> 0:07:22.840 he's rolling forever. So after he rolls twice, he thinks, God, 0:07:22.880 --> 0:07:25.600 when am I ever going to stop rolling? So it 0:07:25.640 --> 0:07:28.280 seemed like time had slowed down for him. And when 0:07:28.280 --> 0:07:31.440 he was thinking about this later, he estimated it would 0:07:31.480 --> 0:07:34.000 take him about two and a half or three seconds 0:07:34.040 --> 0:07:37.840 to think that particular thought, And so that provided him 0:07:37.840 --> 0:07:41.720 with a timescale of the amount of time that a 0:07:41.840 --> 0:07:46.280 single roll seemed to take. So when he calculated this 0:07:46.360 --> 0:07:50.480 later in retrospect, he determined that the whole event seemed 0:07:50.480 --> 0:07:53.480 to have taken about fifteen seconds, but it couldn't have 0:07:53.480 --> 0:07:57.760 taken any longer than five or another report I collected 0:07:57.920 --> 0:08:00.720 was from a mother who saw her three year old 0:08:00.800 --> 0:08:04.800 child fall into the shallow part of a lake at 0:08:04.800 --> 0:08:07.800 a little distance away at a park. So, like any 0:08:07.880 --> 0:08:12.040 parent would, she started immediately sprinting towards the lake, but 0:08:12.200 --> 0:08:15.360 it seemed to take forever to reach there. Now, her 0:08:15.480 --> 0:08:17.720 child was fine, and in fact it didn't take her 0:08:17.720 --> 0:08:21.960 that long, but she was haunted by remembering her thoughts 0:08:22.400 --> 0:08:26.400 during what seemed like a painfully slow process of reaching 0:08:26.440 --> 0:08:31.080 her child. And this impression that time runs slowly is 0:08:31.120 --> 0:08:35.600 not an uncommon occurrence. Other people I interviewed describe things 0:08:35.720 --> 0:08:39.800 like car accidents where they watched the whole event unfold 0:08:39.960 --> 0:08:45.440 slowly with a kind of inevitability, the car sliding towards 0:08:45.480 --> 0:08:49.920 them impacts and the door crushes and so on, Or 0:08:49.960 --> 0:08:52.839 the victim of a mugging describing the way that the 0:08:52.920 --> 0:08:57.079 mugger reaches into his jacket to draw a weapon, or 0:08:57.559 --> 0:09:00.679 a person who's been in an accident with his skateboard 0:09:01.000 --> 0:09:04.680 going towards the parked car. All of these things involve 0:09:04.760 --> 0:09:08.880 very short time windows that for some reason seem very lengthy, 0:09:09.480 --> 0:09:13.080 and these people, like me, reported that the sensation of 0:09:13.120 --> 0:09:17.200 time had seemed to proceed more slowly than normal, And 0:09:17.240 --> 0:09:20.760 so these reports made it seem possible to me that 0:09:20.840 --> 0:09:24.720 the brain has a capacity to operate at a higher 0:09:25.360 --> 0:09:28.320 frame rate, which is how filming slow motion in the 0:09:28.360 --> 0:09:32.600 movies works. You capture information at a higher frame rate 0:09:33.000 --> 0:09:36.480 and then you play it back at normal speed. But 0:09:36.480 --> 0:09:39.800 what if there was another possibility here? What if, for example, 0:09:39.920 --> 0:09:43.679 it's a trick of memory, such that you're laying down 0:09:43.840 --> 0:09:47.240 denser memories and when you read it back out, your 0:09:47.280 --> 0:09:51.440 brain's only conclusion is, well, if I have that much memory, 0:09:51.840 --> 0:09:55.720 that must correspond to five seconds, when in fact it 0:09:55.760 --> 0:09:59.040 only lasted one second. So I wanted to understand what 0:09:59.080 --> 0:10:03.600 was happening here the brain, So I scoured the neuroscience literature, 0:10:04.120 --> 0:10:06.520 but it turned out no one had ever put the 0:10:06.600 --> 0:10:11.520 question of slow motion perception to the test. Why not, Well, 0:10:11.559 --> 0:10:16.319 it's because it would require placing volunteer subjects in life 0:10:16.320 --> 0:10:20.439 threatening situations, which is not a clear path to tenure 0:10:20.480 --> 0:10:25.880 for an academic. But without a rigorous scientific experiment, I 0:10:25.960 --> 0:10:30.120 realized it was difficult to know how to interpret these experiences, 0:10:30.200 --> 0:10:34.080 including my own, from a neuroscience point of view, and 0:10:34.120 --> 0:10:43.640 I was obsessed with figuring out how to test this first, 0:10:43.720 --> 0:10:48.480 I needed something scary, so I packed up stopwatches and 0:10:48.559 --> 0:10:51.160 pads of paper, and I took all the members of 0:10:51.200 --> 0:10:55.319 my laboratory to Astraworld, which was the local amusement park, 0:10:56.480 --> 0:10:59.840 and we set out to find the most terrifying roller coaster. 0:11:04.720 --> 0:11:07.360 We had a fantastic time as a group, and we 0:11:07.440 --> 0:11:09.800 did a lot of laughing, but at the end of 0:11:09.840 --> 0:11:13.880 the day we couldn't find anything frightening enough to give 0:11:13.960 --> 0:11:17.280 us the impression that time had moved in slow motion. 0:11:18.040 --> 0:11:23.240 We needed something more terrifying, so we kept looking, and 0:11:23.559 --> 0:11:27.400 three weeks later, and three hundred miles away, we found it. 0:11:28.120 --> 0:11:37.600 SCAD diving Now SCAD stands for suspended catch air device. 0:11:38.480 --> 0:11:42.640 Imagine a huge metal tower. It's one hundred and fifty 0:11:42.679 --> 0:11:46.600 feet tall. It's kind of like a poor man's Eiffel Tower, 0:11:47.320 --> 0:11:50.520 and you step on a small platform that pulls you 0:11:50.720 --> 0:11:54.360 up like a small elevator, and you find yourself standing 0:11:54.440 --> 0:11:57.600 at the very top of the tower, looking down on 0:11:57.640 --> 0:12:01.760 the city. Now, you put what a big leather harness 0:12:01.840 --> 0:12:04.960 on your back, and then you click the front of 0:12:05.000 --> 0:12:09.120 your harness into a bolet hook. You position yourself so 0:12:09.160 --> 0:12:12.480 that you're hanging from the hook. Cradled in that piece 0:12:12.520 --> 0:12:17.920 of leather, dangling in the air with a net one 0:12:18.040 --> 0:12:22.439 hundred and fifty feet below you, and then the hook 0:12:22.640 --> 0:12:29.560 releases and you are in free fall backwards, looking at 0:12:29.640 --> 0:12:33.839 the sky, falling backwards, not even able to see where 0:12:33.880 --> 0:12:37.680 the net is or how much time you have left. 0:12:38.240 --> 0:12:41.760 When you finally hit the net below, you're going seventy 0:12:41.840 --> 0:12:46.960 miles an hour, and the net catches you softly and 0:12:47.000 --> 0:12:53.240 you finally breathe again. This was sufficiently scary. Now I'm 0:12:53.240 --> 0:12:55.559 going to get back to the experiment in just a moment, 0:12:55.679 --> 0:12:59.160 but first I want to specify that this isn't your 0:12:59.240 --> 0:13:02.000 typical in lab science experiment. So I had to do 0:13:02.080 --> 0:13:05.040 a lot of convincing to get the university to sign off. 0:13:05.120 --> 0:13:09.240 It took me seven months, but we were finally ready. 0:13:10.400 --> 0:13:14.400 So before we tested anyone, I took the plunge myself 0:13:14.520 --> 0:13:17.000 three times in a row, and I can tell you 0:13:17.360 --> 0:13:22.080 that each time was equally terrifying as the previous. There's 0:13:22.520 --> 0:13:26.080 no getting used to falling backwards from a height like that. 0:13:26.280 --> 0:13:29.720 It goes against every Darwinian instinct that you have in 0:13:29.840 --> 0:13:33.800 terms of staying alive. But back to the question, we've 0:13:33.800 --> 0:13:37.679 now found something sufficiently scary, how do we do the 0:13:37.760 --> 0:13:42.080 experiment to see if people are overclocking or having a 0:13:42.080 --> 0:13:48.120 faster frame rate in the moment. So in my lab 0:13:48.200 --> 0:13:51.880 we engineered a wristband that we called the eagle eye, 0:13:52.360 --> 0:13:56.400 or more technically the perceptual chronometer, which is just a 0:13:56.400 --> 0:13:59.800 fancy way of saying something that can measure the speed 0:13:59.840 --> 0:14:03.280 of your perception, in other words, how fast you're taking 0:14:03.320 --> 0:14:07.120 in information from the world. So picture this. It's like 0:14:07.160 --> 0:14:10.560 a watch with a big face, and it has a 0:14:10.600 --> 0:14:16.640 rectangular screen of small LED lights. So we can display 0:14:16.640 --> 0:14:19.000 a number on it, let's say the number twenty seven, 0:14:19.640 --> 0:14:23.320 by turning on the LEDs that make that number. But 0:14:23.440 --> 0:14:26.880 here's the trick. We now switch the lights so that 0:14:27.040 --> 0:14:30.200 in the next moment, all the LEDs that are on 0:14:30.480 --> 0:14:33.960 turn off, and all the ones off turn on, So 0:14:34.040 --> 0:14:37.000 that still shows you a twenty seven, But now it's 0:14:37.040 --> 0:14:39.880 like a negative photograph where the background is lit but 0:14:39.920 --> 0:14:42.160 the number is so you can still easily read that 0:14:42.240 --> 0:14:46.000 as twenty seven. Now what we do is we alternate 0:14:46.120 --> 0:14:49.440 the positive and negative images rapidly, so all the lights 0:14:49.480 --> 0:14:52.840 are blinking on and off and at a fast pace. 0:14:52.920 --> 0:14:55.720 You can still easily see that the number being displayed 0:14:55.840 --> 0:14:58.440 is twenty seven, But if we make it just a 0:14:58.520 --> 0:15:01.560 little bit faster than that, you can't see any number 0:15:01.600 --> 0:15:05.160 at all, because the speed is such that the positive 0:15:05.160 --> 0:15:08.640 and negative images fuse together, and it looks like just 0:15:08.720 --> 0:15:11.240 a bunch of LEDs that are on, and you can't 0:15:11.240 --> 0:15:14.920 distinguish that number twenty seven from any other number that 0:15:15.000 --> 0:15:18.280 might be displayed. So this speed is known as the 0:15:18.320 --> 0:15:23.080 flicker fusion frequency. Things are flickering so fast that they 0:15:23.160 --> 0:15:27.920 all fuse together. Perceptually, now we know that even though 0:15:27.960 --> 0:15:31.200 you can't see the number anymore, there are cells in 0:15:31.240 --> 0:15:35.200 your visual cortex that can follow flicker at much higher 0:15:35.320 --> 0:15:38.920 rates than your consciousness can. So the question was this, 0:15:39.640 --> 0:15:43.400 if you're in a terrifying event, can you actually see 0:15:43.400 --> 0:15:46.840 in slow motion like Neo in the matrix who season 0:15:46.880 --> 0:15:51.680 bullet time? And can you therefore distinguish the flashing numbers 0:15:51.760 --> 0:15:54.600 at a faster rate than you would be able to normally. 0:15:55.360 --> 0:15:58.520 In other words, we set the pace of alternating lights 0:15:59.240 --> 0:16:02.360 just faster than then you can normally see, just beyond 0:16:02.440 --> 0:16:06.840 the flicker fusion frequency. So if your vision speeds up 0:16:06.920 --> 0:16:10.400 like a slow motion camera taking in more frames per second, 0:16:11.160 --> 0:16:14.040 then you should be able to report the number that 0:16:14.160 --> 0:16:17.760 was being flashed. If, on the other hand, you're not 0:16:18.120 --> 0:16:21.040 actually seeing in slow motion but instead just laying down 0:16:21.040 --> 0:16:25.160 more memory, you'd be no faster at reading the display 0:16:25.320 --> 0:16:28.120 and it wouldn't look like anything to you. So we 0:16:28.160 --> 0:16:32.440 got twenty three volunteer participants to do the fall, and 0:16:32.520 --> 0:16:36.160 here's how it works. Imagine you're the volunteer. First, we 0:16:36.280 --> 0:16:41.920 measure your flicker fusion threshold under normal relaxed circumstances, in 0:16:41.960 --> 0:16:45.960 other words, how fast I can alternate these numbers before 0:16:46.040 --> 0:16:49.840 you can't see them anymore. Then we put you on 0:16:49.920 --> 0:16:54.760 the platform that's winched fifteen stories up above the ground. 0:16:55.440 --> 0:16:59.320 You strap the perceptual chronometer to your wrist, and then 0:16:59.360 --> 0:17:02.840 you're attacked to this bolet hook that's dangling way above 0:17:02.880 --> 0:17:06.399 the net, and we set the speed of alternation of 0:17:06.440 --> 0:17:09.320 the lights to just slightly faster than you can see 0:17:09.400 --> 0:17:12.840 any number on there, and you're instructed to keep your 0:17:12.840 --> 0:17:15.920 eyes on your wrist in front of you. And then 0:17:16.200 --> 0:17:22.639 at a moment you're not expecting the hook releases during 0:17:22.680 --> 0:17:26.199 the fall, your only job is to identify the random 0:17:26.280 --> 0:17:29.800 number flashing on the watch. That's it. If you're having 0:17:29.960 --> 0:17:34.240 higher temporal resolution. During the free fall, the rate of 0:17:34.240 --> 0:17:38.120 alternation should appear slowed, which would allow you to read 0:17:38.160 --> 0:17:42.520 the numbers that would otherwise be unreadable. But that was 0:17:42.560 --> 0:17:45.800 only one part of the experiment. After the fall, we 0:17:45.880 --> 0:17:51.960 had participants retrospectively reproduce how long their fall took using 0:17:51.960 --> 0:17:55.840 a stopwatch. So you think back on your fall and 0:17:55.920 --> 0:17:59.400 you start the stopwatch when you picture the hook being released, 0:18:00.040 --> 0:18:02.400 and you stop when you think you hit the net, 0:18:02.960 --> 0:18:06.720 so you're reproducing it in your mind. And then what 0:18:06.760 --> 0:18:09.040 you also do is you watch other people take the 0:18:09.119 --> 0:18:13.440 fall and you reproduce that memory on your stopwatch as well, 0:18:13.520 --> 0:18:16.320 so the moment they were released to the moment they 0:18:16.400 --> 0:18:19.840 hit the net in your memory. And what we found here, 0:18:20.359 --> 0:18:24.359 consistent with the verbal reports, is that everyone estimates to 0:18:24.359 --> 0:18:28.400 the duration of their own fall to be longer than 0:18:28.440 --> 0:18:32.480 when they're remembering someone else's fall the same fall. On average, 0:18:32.560 --> 0:18:35.240 people felt that their own falls took at least thirty 0:18:35.280 --> 0:18:39.760 percent longer. But the surprise came with the results from 0:18:39.760 --> 0:18:43.879 the perceptual chronometer. No one was able to read the 0:18:43.960 --> 0:18:47.200 numbers in free fall at a faster rate than they 0:18:47.240 --> 0:18:50.479 could when they were standing calmly on the ground and 0:18:50.520 --> 0:18:53.000 It's not because they closed their eyes or didn't pay attention. 0:18:53.160 --> 0:18:57.800 We monitored for that carefully, but because they couldn't, after all, 0:18:58.480 --> 0:19:04.159 see time and slow So despite my subjective experience of 0:19:04.200 --> 0:19:07.800 falling from the roof, I hadn't, after all seen my 0:19:07.960 --> 0:19:12.359 surroundings in bullet time like NEO. Now, this wasn't necessarily 0:19:12.400 --> 0:19:15.760 the result I was expecting, So we analyzed this data 0:19:15.880 --> 0:19:18.080 every which way to make sure there wasn't a mistake, 0:19:18.160 --> 0:19:22.359 and there wasn't. People weren't actually seeing in slow motion, 0:19:22.760 --> 0:19:25.879 and this was the first step to realizing the link 0:19:26.000 --> 0:19:32.479 between time and memory. The reason participants reported a longer 0:19:32.560 --> 0:19:36.360 duration for their own fall, even though they were seeing 0:19:36.720 --> 0:19:41.280 no faster than normal, comes down to a walnut size 0:19:41.320 --> 0:20:06.479 area of the brain called the amygdala. When there's an 0:20:06.520 --> 0:20:11.800 emergency situation, the amygdala kicks into high gear and it 0:20:11.920 --> 0:20:15.080 commandeers the resources of the rest of the brain and 0:20:15.119 --> 0:20:19.880 it forces everything to attend to the situation at hand. Now, 0:20:19.960 --> 0:20:22.879 what's emerged in neuroscience in the last few decades is 0:20:22.920 --> 0:20:27.000 that when the amygdala gets involved, memories are laid down 0:20:27.200 --> 0:20:30.960 on a secondary memory system. This is not your normal 0:20:31.000 --> 0:20:33.880 memory system for every day stuff, which is taken care 0:20:33.920 --> 0:20:40.120 of by the hippocampus, but a secondary track, because that's 0:20:40.119 --> 0:20:45.080 what memories are for. In an emergency situation, when everything 0:20:45.119 --> 0:20:47.160 is hitting the fan, that's when you want to make 0:20:47.200 --> 0:20:50.720 sure that you write down all the details for future reference. 0:20:51.440 --> 0:20:56.080 Now here's the key. When you play these memories back out, 0:20:56.840 --> 0:21:01.000 your brain interprets the higher density of data as a 0:21:01.160 --> 0:21:08.280 longer duration. So under normal everyday circumstances, most of what 0:21:08.480 --> 0:21:12.080 happens to you passes right through your system and very 0:21:12.119 --> 0:21:15.840 little gets retained. You don't remember much of anything about 0:21:15.840 --> 0:21:18.320 the details of who you passed on the street today, 0:21:18.720 --> 0:21:21.600 or all the billboards you saw on your drive, or 0:21:21.600 --> 0:21:23.920 the color of the car in front of you, or 0:21:24.119 --> 0:21:25.600 who was in front of you in line at the 0:21:25.600 --> 0:21:30.240 coffee shop, or much else. When you're judging how long 0:21:30.320 --> 0:21:33.040 something lasted, the only way you can do it is 0:21:33.080 --> 0:21:37.920 by looking back and essentially counting up memories. Your brain 0:21:37.960 --> 0:21:40.919 doesn't get time information for free. It's not like it 0:21:40.920 --> 0:21:44.080 has a built in clock. It's made up of billions 0:21:44.080 --> 0:21:46.320 of cells and that's all it has to work with. 0:21:50.359 --> 0:21:54.840 So through experience it figures out how to make correlations. 0:21:55.359 --> 0:21:57.560 If I have this much memory I can draw on, 0:21:58.040 --> 0:22:02.200 then that event must have lasted ten seconds, or ten months, 0:22:02.280 --> 0:22:05.840 or ten years. And in this way, duration is always 0:22:05.920 --> 0:22:10.440 a retrospective estimate and is totally dependent on how much 0:22:10.640 --> 0:22:15.720 memory you have, what landmarks you can identify in your 0:22:15.760 --> 0:22:20.840 memory landscape. And this is why time and memory are linked. 0:22:21.400 --> 0:22:25.520 But here's what's really important to know about this consciousness. 0:22:25.920 --> 0:22:29.000 Your experience of the world right now, it's always a 0:22:29.080 --> 0:22:34.920 story that's told retrospectively. You're not conscious of anything in 0:22:34.960 --> 0:22:38.760 the moment in real time. But consciousness is always about 0:22:38.840 --> 0:22:42.320 your brain asking itself what just happened? What just happened, 0:22:42.840 --> 0:22:46.399 and it pulls the appropriate signals from whatever is available 0:22:46.480 --> 0:22:50.480 to answer that question. So the reason that police officer 0:22:50.600 --> 0:22:55.080 remembered his gunshots as being far apart in time is 0:22:55.119 --> 0:22:58.880 because he was laying down so many details of the footage, 0:22:58.920 --> 0:23:03.480 so many memories. The car is approaching him, he jumps 0:23:03.520 --> 0:23:05.960 out of the way, he hits the ground, he's shooting 0:23:05.960 --> 0:23:09.080 at the side, he shoots at the back window, the 0:23:09.320 --> 0:23:14.000 closeness of the squealing tires, one hundred other details. All 0:23:14.080 --> 0:23:19.080 that gets stored by this emergency memory storage system. And 0:23:19.160 --> 0:23:22.480 so when his brain says, what just happened, what just happened, 0:23:22.640 --> 0:23:26.240 he has such a density of memory that his brain 0:23:26.359 --> 0:23:30.240 concludes naturally that the event must have been spread out 0:23:30.280 --> 0:23:33.480 over a long time. And the same goes for that 0:23:33.800 --> 0:23:38.440 doctor in the motorcycle accident. In a normal five seconds 0:23:38.480 --> 0:23:41.399 of riding along on the road, not much as getting 0:23:41.440 --> 0:23:44.600 written down in your memory, But when you're on the road, 0:23:44.840 --> 0:23:48.880 rolling on the asphalt, and possibly about to die, your 0:23:48.920 --> 0:23:52.680 brain is keeping track of everything it can. So when 0:23:52.680 --> 0:23:56.000 your brain says what just happened, it has such a 0:23:56.200 --> 0:24:00.200 density of memories that it assumes the event lasted longer. 0:24:01.200 --> 0:24:04.879 Now getting back to the test that I conducted. After 0:24:04.920 --> 0:24:09.920 I published these results, several people independently said to me, Hey, 0:24:09.960 --> 0:24:12.560 I read your paper, but I think you're wrong because 0:24:12.680 --> 0:24:16.880 I know that I experienced the car accident in slow motion. 0:24:17.640 --> 0:24:20.600 So I just asked them, look, the person who was 0:24:20.640 --> 0:24:23.639 sitting next to you on the passenger seat, did it 0:24:23.760 --> 0:24:30.040 really sound like they were saying, Because if not, then 0:24:30.080 --> 0:24:34.399 you weren't actually experiencing the world in slow motion. And 0:24:34.600 --> 0:24:37.560 they have to allow that if time were really stretched out, 0:24:38.000 --> 0:24:41.119 everything would have to be in slow motion like a movie. 0:24:41.880 --> 0:24:44.879 So I want to add there are some interesting exceptions 0:24:44.920 --> 0:24:49.000 to this slow motion effect. It only happens in certain circumstances, 0:24:49.600 --> 0:24:52.960 and the reason is because it depends on whether or 0:24:53.040 --> 0:24:58.160 not you're expecting or foreseeing the disaster that's heading your way. 0:24:58.800 --> 0:25:01.840 This is what I call the sliding on ice towards 0:25:01.840 --> 0:25:06.040 a brick wall phenomenon. If you're in that situation and 0:25:06.080 --> 0:25:09.399 you see what's coming, then all of your attention is 0:25:09.600 --> 0:25:13.600 riveted on the details, and so as we just saw, 0:25:13.680 --> 0:25:17.800 you're capturing them for later analysis in your memory. So 0:25:17.960 --> 0:25:21.840 you have the retrospective impression that it all must have 0:25:21.880 --> 0:25:27.120 taken a long time. But interestingly, when something unexpected happens, 0:25:27.119 --> 0:25:30.160 when you don't see it coming at all, you don't 0:25:30.200 --> 0:25:33.560 have time to put your attentional systems on it and 0:25:33.600 --> 0:25:37.000 write down the memories, and in retrospect, it seems like 0:25:37.040 --> 0:25:40.280 it happened with no time at all. Once, when I 0:25:40.400 --> 0:25:44.000 was biking, my front tire went into a pothole and 0:25:44.040 --> 0:25:46.959 I went flying over the handlebars. But I don't remember 0:25:47.000 --> 0:25:49.120 anything from the event because the whole thing came as 0:25:49.119 --> 0:25:51.960 a surprise. I didn't see it coming. And this is 0:25:52.000 --> 0:25:55.600 what happens when people are t boned in their car 0:25:55.720 --> 0:25:59.400 by a vehicle that they didn't see. The event doesn't 0:25:59.400 --> 0:26:02.880 seem to run slow motion, but instead it's as though 0:26:02.960 --> 0:26:06.359 time is gone. They were driving along through the intersection, 0:26:06.760 --> 0:26:09.320 and in the next moment their car was pinned up 0:26:09.359 --> 0:26:13.520 against the lamp post without any notion of what the 0:26:13.560 --> 0:26:17.679 heck just happened. So I noticed when I interviewed people 0:26:17.720 --> 0:26:21.159 that they described all the predictable things as though they 0:26:21.240 --> 0:26:24.639 happened in slow motion because they had so many detailed 0:26:24.680 --> 0:26:29.159 memories about them. But they don't describe the airbag is 0:26:29.200 --> 0:26:33.840 coming out in slow motion because that happens totally unexpectedly. Now, 0:26:33.880 --> 0:26:36.320 let me get back to the big question. What is 0:26:36.359 --> 0:26:39.959 this link between time and memory have to do with 0:26:40.000 --> 0:26:46.760 our normal lives. Well, this is why time seems to 0:26:46.840 --> 0:26:49.520