WEBVTT - How Optical Illusions Work 0:00:00.720 --> 0:00:03.640 Hey, March is tripod month, my friend, and you know 0:00:03.640 --> 0:00:06.680 what that means. Yes, that means it's time to let 0:00:06.920 --> 0:00:11.360 people know about your favorite podcasts, just to share the 0:00:11.480 --> 0:00:14.400 sheer joy of podcast listening. That's right, it's t r 0:00:14.640 --> 0:00:17.479 y pod still in nascent industry. A lot of people 0:00:17.520 --> 0:00:20.880 don't know what podcasts are and helps everybody out if 0:00:20.920 --> 0:00:24.240 you would go out and just say, hey, family member, 0:00:24.640 --> 0:00:26.920 who I see it? Thanksgiving once a year? Right, you 0:00:26.960 --> 0:00:29.000 should try out this thing called a podcast. Here's what 0:00:29.040 --> 0:00:30.920 they are. Here's a cool show you should try, and 0:00:30.960 --> 0:00:32.479 here's how to get it. Yeah, and it doesn't have 0:00:32.520 --> 0:00:34.800 to be our show, just any podcast you like in 0:00:34.880 --> 0:00:38.320 general that you think someone else would like, just share it. Yeah, 0:00:38.600 --> 0:00:44.120 So get on board the dry pod train. Welcome to 0:00:44.520 --> 0:00:53.840 stuff you should know from house stuff Works dot com. Hey, 0:00:53.880 --> 0:00:57.000 and welcome to the podcast. I'm Josh Clark, This Charles W. 0:00:57.160 --> 0:01:00.760 Chuck Bryant, and there is well Jerry just issappure Chuck 0:01:01.440 --> 0:01:05.400 did she she did? Oh? There she's back. David copper 0:01:05.440 --> 0:01:08.480 Fields in here with us as well. Today he made 0:01:08.480 --> 0:01:12.520 the Statue of Liberty disappear. And now Jerry Jerry as 0:01:12.600 --> 0:01:17.319 drawn by mc escher. Oh that's nice. How do you 0:01:17.319 --> 0:01:27.080 feel about optical illusions? I feel I feel happy about 0:01:27.160 --> 0:01:31.440 optical illusions. I'm not asking Josh from the third grade, 0:01:31.680 --> 0:01:38.880 but I feel sad about articles on optical illusions in general. 0:01:39.160 --> 0:01:41.959 It's a it's a really difficult thing to write about, 0:01:42.240 --> 0:01:45.160 as we're about to demonstrate, it's an even more difficult 0:01:45.160 --> 0:01:50.360 thing to talk about. Um. But it's just I think 0:01:50.520 --> 0:01:55.360 the idea that every article has to inherently describe an 0:01:55.360 --> 0:02:00.240 optical illusion and then basically follows that discrip o shin 0:02:00.400 --> 0:02:03.640 up with and scientists don't really know what's going on. 0:02:03.920 --> 0:02:06.640 Here's a couple of guesses that will be fully discredited 0:02:06.640 --> 0:02:10.400 in twenty years. It's just dissatisfying. Yeah, I mean because 0:02:10.400 --> 0:02:12.280 we were kind of we're the kind of dudes who 0:02:12.320 --> 0:02:17.840 like concrete answers or at least like really solid hypotheses. 0:02:17.960 --> 0:02:21.400 Some of these are flimsy to me. Yeah, So we 0:02:21.440 --> 0:02:26.480 would encourage folks if you are listening at home or work, 0:02:26.880 --> 0:02:30.360 because you can blow off work. Let's be honest, um, like, 0:02:30.440 --> 0:02:32.200 look look up. Some of these will describe them as 0:02:32.240 --> 0:02:34.760 best we can, and most of them you've probably seen 0:02:34.800 --> 0:02:40.440 before because as you will learn, uh many many illusions 0:02:40.520 --> 0:02:45.720 optical illusions were were drawn and conceived many years ago, 0:02:46.440 --> 0:02:49.680 and I have just been sort of played upon over 0:02:49.720 --> 0:02:52.880 the years in different ways. Right. Yeah, the nineteenth century was, 0:02:52.919 --> 0:02:57.960 like the classics, the foundation of optical illusions, which not 0:02:58.120 --> 0:03:04.120 coincidentally coincided with the foundation of psychology and brain research. Um, 0:03:04.160 --> 0:03:06.880 and optical illusions were created to kind of test the 0:03:06.919 --> 0:03:09.920 stuff or explore this stuff, right. But yeah, most of 0:03:09.919 --> 0:03:13.080 the stuff today are just variations on these themes. Yeah. So, 0:03:13.120 --> 0:03:15.040 like I was saying, if you're if you're able to 0:03:15.320 --> 0:03:18.520 just you know, kind of just google this junk as 0:03:18.560 --> 0:03:21.840 we say them, and you'll go, oh that thing and chuck. Actually, 0:03:21.880 --> 0:03:26.880 there's a website called Michael Bach dot d E okay 0:03:27.480 --> 0:03:32.680 might yeah, which is Deutscheland Germany in the English, but 0:03:32.800 --> 0:03:35.000 it's h M I C H A E l B 0:03:35.240 --> 0:03:37.720 A c H dot d E. And this guy just 0:03:37.880 --> 0:03:41.360 listed he's got links to every optical illusion you could 0:03:41.400 --> 0:03:43.640 possibly imagine. So that'd be a good place to go. 0:03:43.960 --> 0:03:46.040 Just sit there and click on his site while we're 0:03:46.040 --> 0:03:50.040 talking about these things. Yeah, and UM, what I found 0:03:50.080 --> 0:03:53.720 is that I get um a bit of optical illusion 0:03:53.800 --> 0:03:56.400 fatigue when I look at too many of these things 0:03:56.400 --> 0:03:59.560 in a row. Oh, well that should be studied. Well, 0:04:00.360 --> 0:04:03.040 I think that. I mean, we know so little about 0:04:03.080 --> 0:04:07.720 optical illusions that that is, I mean, that's kind of groundbreaking. Well, 0:04:08.800 --> 0:04:11.840 I don't mean fatigue is in like scientifically, I just 0:04:11.920 --> 0:04:13.960 mean like I'm tired of looking at this junk. Oh, 0:04:14.000 --> 0:04:16.240 I see what you mean. Yeah, it just bores me 0:04:16.279 --> 0:04:20.120 after a bit. Plus a lot of require ugly color 0:04:20.240 --> 0:04:24.039 combinations or un unpleasant color combinations. So I think that 0:04:24.120 --> 0:04:27.719 probably contributes to it too. And we should do a 0:04:29.200 --> 0:04:30.760 We don't talk a lot about Er in this one, 0:04:30.800 --> 0:04:33.400 but we should. He deserves his own show. Sure, you 0:04:33.440 --> 0:04:36.760 know Escher and Geiger. Maybe we'll do a combo show 0:04:36.800 --> 0:04:40.760 with those two. Oh yeah, oh yeah, man, that guy's 0:04:40.760 --> 0:04:44.920 brain is beautiful. Yeah. There's a lot of cultural icon 0:04:45.000 --> 0:04:48.279 biographies that are floating out there. Mr Rogers and Dr SEUs. 0:04:48.360 --> 0:04:50.560 I know we've talked about those. So maybe we'll go 0:04:50.560 --> 0:04:55.160 on a kick. Okay, I'm ready for some kicking. Alright, 0:04:55.200 --> 0:04:57.599 so we were Let's go back a little bit to 0:04:57.720 --> 0:05:01.400 the history of thinking about or study optical illusions. Right, 0:05:02.400 --> 0:05:06.039 As with most things in the West, the basis of 0:05:06.080 --> 0:05:09.120 optical illusions of the first mention of optical illusions in 0:05:09.120 --> 0:05:13.520 the literature comes from the Greeks and Aristotle in particular. Yeah. 0:05:13.560 --> 0:05:18.680 He uh, he probably munched on some some some weird 0:05:18.760 --> 0:05:21.960 route and stared at a waterfall for a little while 0:05:23.160 --> 0:05:26.080 and he said, hey, dudes, if you stare at that 0:05:26.120 --> 0:05:29.359 waterfall long enough, man, and then you quickly look at 0:05:29.440 --> 0:05:32.560 that rock, it looks like the rock is moving, right, 0:05:34.080 --> 0:05:40.400 and then the rocks like, AREM not moving? Aristotle? But 0:05:40.520 --> 0:05:44.719 that actually has a name, correct, Yeah, it's called the 0:05:44.720 --> 0:05:50.400 waterfall illusion appropriately or um, what's the other word for it, 0:05:50.560 --> 0:05:53.159 the motion after effect. Yeah, that's what I was looking for. 0:05:53.560 --> 0:05:57.400 This is this is like, if this is true the 0:05:57.520 --> 0:06:00.760 explanation for it, then I'm just disappointed with our our 0:06:00.800 --> 0:06:04.800 brains hit. The explanation is that when we're staring at 0:06:04.880 --> 0:06:08.239 the waterfall, are neurons tracking the movement of the water 0:06:08.760 --> 0:06:14.160 become tired out, exhausted, yeah, overwhelmed. So when we stopped 0:06:14.200 --> 0:06:16.479 looking at it and they take a break, all the 0:06:16.560 --> 0:06:19.360 other ones that weren't at work are suddenly working over 0:06:19.440 --> 0:06:23.160 time and making things move that aren't actually moving right. 0:06:23.640 --> 0:06:28.000 That's a stupid explanation. Uh, I don't know how buy that. 0:06:29.080 --> 0:06:31.160 I mean, it makes sense but I think it's stupid, 0:06:31.160 --> 0:06:34.520 it's boring, you know, just worn out neurons. Yeah, I'm 0:06:34.600 --> 0:06:38.720 tired to sit down over here. Uh yeah. And then 0:06:38.760 --> 0:06:40.720 there was, um, if we go forward a bit in 0:06:40.760 --> 0:06:43.599 the nineteenth century, like you were talking about, there was 0:06:44.600 --> 0:06:47.120 that that was when people got really sort of interested 0:06:47.279 --> 0:06:51.640 in studying these things and what was going on in 0:06:51.680 --> 0:06:55.120 the brain, because it's sort of coincided with um, studying 0:06:55.160 --> 0:07:00.479 perception and how our eyes worked, and how our eyes 0:07:00.520 --> 0:07:04.680 worked in relation to our brain. Right. And then I 0:07:04.720 --> 0:07:08.120 guess what some of the earliest optical illusions kind of 0:07:08.240 --> 0:07:14.320 proved though, was this longstanding idea that it are perception 0:07:14.360 --> 0:07:18.800 of vision. Our visual experience was based in how the 0:07:18.920 --> 0:07:24.120 eyes interpreted objects. And what these early optical illusions started 0:07:24.160 --> 0:07:27.960 to prove was, no, it's actually the brain that's getting 0:07:28.000 --> 0:07:32.200 messed up here. And some now we're starting to get 0:07:32.240 --> 0:07:35.560 into here at this point, like some some theories that 0:07:35.560 --> 0:07:37.520 that makes sense to me, that I think are cool. 0:07:37.800 --> 0:07:41.400 But what these this early study started to reveal was 0:07:41.440 --> 0:07:45.240 that the brain is extremely lazy and it likes to 0:07:45.280 --> 0:07:49.000 take shortcuts. Right, Yeah, I thought, I thought this is 0:07:49.040 --> 0:07:51.200 actually pretty interesting. Are you talking about the lag time? 0:07:51.880 --> 0:07:54.520 The lag time, but also, yeah, there's there's plenty of 0:07:54.520 --> 0:07:56.600 other stuff, but the lag time seems to me to 0:07:56.680 --> 0:08:01.360 be like one specific slice of this the general tricks 0:08:01.360 --> 0:08:04.400 of the trade that the brain uses to cut corners. Yeah, 0:08:04.520 --> 0:08:07.600 and the lag time is basically, when you know, everything 0:08:07.600 --> 0:08:10.400 seems to happen instantaneous when you when you look at something, 0:08:10.800 --> 0:08:13.600 your eyeballs pick it up, the neurons start firing, and 0:08:13.640 --> 0:08:15.640 the brain tells you, you know, that's a coffee cup. 0:08:16.200 --> 0:08:19.280 But there's just the slightest little lag and the time 0:08:19.320 --> 0:08:22.000 it takes for that to happen. And one of the 0:08:22.000 --> 0:08:25.760 theories with optical illusions is the brain is trying to 0:08:25.840 --> 0:08:30.720 predict and that slight, slight, slight. You know, I'm not 0:08:30.760 --> 0:08:37.040 good with small uh. Units of time is nanosecond, Jordana, Yeah, Nana, 0:08:37.080 --> 0:08:39.280 second is definitely sure, but I think we're talking tenth 0:08:39.320 --> 0:08:42.600 of a second, Okay, So the brain basically tries to 0:08:42.640 --> 0:08:47.319 predict what what is should come next based on what 0:08:47.360 --> 0:08:49.760 we're used to seeing in real life. Is that a 0:08:49.800 --> 0:08:51.960 good way to say it? Yeah? And the reason they 0:08:52.000 --> 0:08:54.280 would do this is because a tenth of a second, 0:08:54.320 --> 0:08:58.280 something can change, like a tiger can suddenly appear. Um, 0:08:58.320 --> 0:09:01.200 so the brain is constantly looking clues in the environment 0:09:01.240 --> 0:09:05.120 to to predict what what is that what a tenth 0:09:05.120 --> 0:09:07.199 of a second in the future is going to be? Like, right, 0:09:08.080 --> 0:09:12.240 I think things move slow enough for us humans that 0:09:12.760 --> 0:09:16.960 it usually works pretty well. But what this researcher Mark 0:09:17.480 --> 0:09:22.199 Changizi says is an optical illusion. Some of the optical 0:09:22.280 --> 0:09:28.520 illusions are actually reliable ways to trick the brain into 0:09:28.520 --> 0:09:31.920 making the wrong decision about what the future is gonna hold. 0:09:32.120 --> 0:09:35.240 One of the ones that that classically falls into this 0:09:35.280 --> 0:09:40.920 example is um what's the one that that he talks 0:09:40.920 --> 0:09:44.560 about where it's the It's the one with the so 0:09:44.640 --> 0:09:50.520 that you've got two parallel lines running horizontally, just you know, 0:09:50.600 --> 0:09:53.840 separated by a little amount of space, and then in 0:09:53.920 --> 0:09:59.359 the background there's radial lines all going toward a um 0:09:59.520 --> 0:10:02.920 the point, the vanishing point on the horizon. Right. Yes, 0:10:03.880 --> 0:10:06.440 I can't remember the name of this one, but the 0:10:06.440 --> 0:10:11.360 the point that Changizi makes is that the radial lines, 0:10:11.440 --> 0:10:14.720 lines that radiate from a center point our brains use 0:10:14.920 --> 0:10:20.800 as a shortcut indicator of motion, the Herring illusion. Thank you. 0:10:22.440 --> 0:10:26.559 So these radial lines that we see tell our brain, oh, 0:10:26.600 --> 0:10:29.440 we're moving and we're moving towards this vanishing point in 0:10:29.480 --> 0:10:33.720 the distance. So these these horizontal lines that are in 0:10:33.720 --> 0:10:37.760 the foreground are actually appear to be bent in the center, 0:10:37.840 --> 0:10:41.240 bent outward from one another very much. So, So what 0:10:41.360 --> 0:10:44.199 Changizi saying is that the brain is predicting since it 0:10:44.280 --> 0:10:46.960 thinks we're moving forward towards this point and then toward 0:10:47.040 --> 0:10:49.440 these lines that as we get closer, they have to 0:10:49.520 --> 0:10:54.160 bend to basically allow us to enter in another way. 0:10:54.400 --> 0:10:56.480 But the thing is that they're they're not moving because 0:10:56.480 --> 0:10:58.600 it's a static image, but it's the brain being tricked 0:10:58.600 --> 0:11:03.280 into thinking we're moving forward, changing our perspective unnecessarily. Yeah, 0:11:03.320 --> 0:11:05.439 because the brain is used to the way we move 0:11:05.480 --> 0:11:09.120 forward in real life. I r L right for you 0:11:09.200 --> 0:11:12.400 kids out there, and so you know, it's a lot 0:11:12.440 --> 0:11:14.600 of this seemed like the brain almost kind of negotiating 0:11:14.640 --> 0:11:18.560 with itself. Yeah, you know, yes, but I think part 0:11:18.600 --> 0:11:21.640 of it so that lag time one makes sense, right. 0:11:22.480 --> 0:11:24.480 Another one that makes sense to me as far as 0:11:24.480 --> 0:11:28.719 why the brain makes shortcuts is that when when like 0:11:28.760 --> 0:11:31.760 the physical world is in at least three dimensions that 0:11:31.840 --> 0:11:35.240 we interact with it in, right, but our eyes are 0:11:35.280 --> 0:11:38.880 giving us two dimensional representations that the brain then has 0:11:38.920 --> 0:11:43.640 to reconstruct into three dimensions, and it's learned to take 0:11:43.760 --> 0:11:48.480 all sorts of neat little um, it's neat little clues 0:11:48.600 --> 0:11:51.640 to put together a pretty good prediction of what it's 0:11:51.679 --> 0:11:55.240 looking at. Yeah, and and it can also flip flop 0:11:55.480 --> 0:11:58.560 between different two different views like the is it the 0:11:58.640 --> 0:12:03.000 Necker cube? I love it any c K E R. 0:12:03.200 --> 0:12:06.280 And it's it's sort of that classic cube that you 0:12:06.360 --> 0:12:10.120 learned to draw, the one that's slightly more advanced and 0:12:10.200 --> 0:12:12.880 than the basic cube that you first learned to draw. 0:12:13.640 --> 0:12:16.079 It's the second cube that you learned to draw right 0:12:16.160 --> 0:12:19.160 on your your What was those things that you put 0:12:19.160 --> 0:12:22.000 on your books and people? Oh, just like yeah, homemade 0:12:22.000 --> 0:12:25.960 book covers, right exactly. Yeah, basically a brown grocery sack 0:12:26.040 --> 0:12:29.240 is what I used. Yeah, same here. Uh that's because 0:12:29.280 --> 0:12:33.800 we were poor. Well plus those those things held up 0:12:34.240 --> 0:12:37.560 oh sure yeah. Um. So you look at the Necker 0:12:37.600 --> 0:12:40.640 cube and um. The fun thing about the Necker cube 0:12:40.720 --> 0:12:42.679 is you you look at it and your brain is 0:12:42.720 --> 0:12:45.120 able to flip back and forth between the cube basically 0:12:45.200 --> 0:12:49.679 having two different um uh positions? Is that the best 0:12:49.720 --> 0:12:51.800 way to say it? I keep saying that, But you 0:12:51.840 --> 0:12:54.440 know again, these things are kind of hard to describe. Well, yeah, 0:12:54.440 --> 0:12:57.240 it's kind of like the cube is transparent and you 0:12:57.280 --> 0:13:00.199 can see all corners of it. Yeah, so you're rain 0:13:00.280 --> 0:13:03.560 is saying, Okay, is that corner close to me or 0:13:03.679 --> 0:13:08.160 furthest away from me? It changes perspective. Yeah, and so 0:13:08.520 --> 0:13:12.200 thanks to UM, to the wonder machine, we can put 0:13:12.240 --> 0:13:17.559 people in these things and UM see the neurons responsible 0:13:17.640 --> 0:13:21.840 for the different perspectives, uh, flipping back and forth depending 0:13:21.880 --> 0:13:26.679 on how we're looking at it. Yeah, exactly. Pretty helpful 0:13:26.720 --> 0:13:29.040 at this point because you had the nineteenth century where 0:13:29.040 --> 0:13:32.600 they started to to suss out that the ideas that 0:13:32.920 --> 0:13:35.319 the brain was responsible for this, it was the brain 0:13:35.440 --> 0:13:39.080 messing up. And then not a lot happened in between 0:13:39.160 --> 0:13:42.240 then and the two thousands when f M R I 0:13:42.400 --> 0:13:45.920 came into UM widespread use. And then now we're starting 0:13:45.920 --> 0:13:48.959 to see, yeah, this the a lot of these early 0:13:49.040 --> 0:13:51.880 theories are actually correct because we can see the neurons 0:13:51.920 --> 0:13:54.640 responsible for them. All Right, Well, let's take a little 0:13:54.640 --> 0:13:57.480 break here and then we're gonna come back and talk 0:13:57.520 --> 0:14:00.320 about the Herman illusion and what the Mr I said 0:14:00.320 --> 0:14:27.280 about that one. Okay, so the Herman Herman I'm not 0:14:27.280 --> 0:14:30.160 sure how to pronounce that H E R M A 0:14:30.400 --> 0:14:34.600 N N. The Herman Grid conceived by Ludamore Herman in 0:14:35.840 --> 0:14:38.480 you nailed this first first name? Oh yeah, Well, it's 0:14:38.520 --> 0:14:41.520 it's one of those classic illusions that we've all seen 0:14:41.640 --> 0:14:44.400 and it's really simple. It's just a black and white 0:14:44.440 --> 0:14:48.040 grid of squares, and that's the one where if you're 0:14:48.040 --> 0:14:50.080 just looking at it, it looks like there's these little 0:14:50.600 --> 0:14:55.440 gray circles, little gray dots in between where these things intersect, 0:14:56.000 --> 0:14:58.280 and there's really nothing there though, of course when you 0:14:58.280 --> 0:15:00.880 focus on that, it goes away. Uh. And the m 0:15:01.000 --> 0:15:03.400 R I showed that when you're looking at an illusion 0:15:03.440 --> 0:15:08.080 like this and others like this, um the neurons are 0:15:08.080 --> 0:15:10.920 competing with one another to see the light and the dark, 0:15:11.440 --> 0:15:15.640 and basically one set of neurons wins out over the 0:15:15.680 --> 0:15:18.600 other and then influences the message to the other. For 0:15:18.640 --> 0:15:21.480 what you end up perceiving, right, fairly interesting and think 0:15:21.720 --> 0:15:23.760 it is it is And this one kind of stands 0:15:23.800 --> 0:15:26.240 on its owner in its own class, and that it's 0:15:26.280 --> 0:15:29.040 not really the brain that's being duped. It's because of 0:15:29.040 --> 0:15:31.640 the physiology of the eyes and the light receptors in 0:15:31.720 --> 0:15:35.160 the eyes. Right, So there are arranged so that they 0:15:35.200 --> 0:15:40.280 are they they sense distinction, like contrast between light and dark, right, 0:15:40.920 --> 0:15:44.240 and if they're sensing both, they create this blob. There's 0:15:44.240 --> 0:15:49.280 spill over where um, some receptors in a single cell 0:15:49.880 --> 0:15:52.720 um are getting dark and some are getting light. When 0:15:52.760 --> 0:15:55.000 you can create these blobs in the intersection, but then 0:15:55.040 --> 0:15:57.560 when you focus your attention on the white part the 0:15:57.600 --> 0:16:02.239 intersection between the black squares, you're using your phobio receptors, 0:16:02.240 --> 0:16:06.880 which have far less inhibition or spill over um, so 0:16:06.920 --> 0:16:09.360 that the gray blob disappears. In what you see is 0:16:09.360 --> 0:16:13.880 is white. It's actually really I read probably like four 0:16:14.040 --> 0:16:17.800 different explanations of it before it started to sink in. Yeah, 0:16:18.200 --> 0:16:22.040 it's straightforward, but it's tough to explain. I think another word. Yeah, 0:16:22.120 --> 0:16:24.800 and uh, I totally agree. Um. And one of the 0:16:24.800 --> 0:16:29.040 reasons we know that these neurons are sort of individually 0:16:29.080 --> 0:16:33.520 picking things up is because in these two dudes, David 0:16:33.600 --> 0:16:39.160 Hubil and torched In Festal, great name, you're going to 0:16:39.240 --> 0:16:42.200 say that, uh, in one they won the Nobel Prize 0:16:42.200 --> 0:16:46.240 in Physiology or Medicine because they found out that there's 0:16:46.240 --> 0:16:50.000 actually a process and how the brain uh picks of stuff. 0:16:50.080 --> 0:16:51.680 Up and and what the I C s. And they 0:16:51.720 --> 0:16:55.800 found that each neuron is actually responsible for one little part, 0:16:55.920 --> 0:16:59.760 one little detail of that pattern uh in the retinal image. 0:16:59.760 --> 0:17:03.080 And so that explains why these neurons can do get 0:17:03.080 --> 0:17:07.320 out basically on what it's seen. Yeah. So, and it's 0:17:07.320 --> 0:17:11.120 not just like uh, like neurons competing seeing light and dark. 0:17:11.240 --> 0:17:16.280 It's it's from what I understand the the understanding of 0:17:16.280 --> 0:17:20.879 our brain and vision is that an individual neuron is 0:17:20.920 --> 0:17:26.399 responsible for, um, say a circle, It sees circles, and 0:17:26.440 --> 0:17:30.359 it's transmitting any circular information to the brain. Another neuron 0:17:30.440 --> 0:17:33.439 is responsible for seeing dark, another is responsible for seeing light, 0:17:33.440 --> 0:17:37.360 another's responsible for seeing red, another is responsible for seeing texture, 0:17:37.760 --> 0:17:41.199 and all of this sensory information, this visual information is 0:17:41.240 --> 0:17:44.320 coming to the brain all at once, and these various 0:17:44.320 --> 0:17:48.480 brain regions responsible for vision putting it together the best 0:17:48.520 --> 0:17:52.560 way it can. You see a red ball. And there's 0:17:52.600 --> 0:17:55.159 a lot of cues that the brain uses that just 0:17:55.280 --> 0:18:01.199 fascinate me. For basically what's called monocular vision. Right, so 0:18:01.240 --> 0:18:03.920 when you are using both of your eyes, especially when 0:18:03.960 --> 0:18:07.760 something's up close, you're getting two separate pictures of the 0:18:07.800 --> 0:18:11.520 same thing, and the differences between these pictures the brain 0:18:11.600 --> 0:18:14.560 can use to easily translate it into three dimensions, right 0:18:14.600 --> 0:18:17.680 to to to handle things like perspective and stuff like that. 0:18:18.000 --> 0:18:21.840 But when something's further away, um, the brain has to 0:18:21.960 --> 0:18:25.280 use other little tricks of the trade. Right. So you've 0:18:25.280 --> 0:18:27.719 got things like inner position. That's a pretty straight up 0:18:27.760 --> 0:18:32.120 one where if one objects in front of another object, 0:18:32.119 --> 0:18:36.199 your brain says, well, the object that's behind is further away. Yeah. 0:18:36.280 --> 0:18:39.359 Is that is that what explains like force perspective? Yes? 0:18:39.880 --> 0:18:44.480 In art, Yes, right, I do like force perspective stuff 0:18:44.560 --> 0:18:46.679 I do. It's kind of cool, it's neat stuff. I 0:18:46.680 --> 0:18:50.800 guess that's that's probably part of the op art movement, right, Uh, yeah, 0:18:50.840 --> 0:18:52.800 when it was at like sixties and seventies. Yeah, it 0:18:52.840 --> 0:18:55.280 seems like yeah. And then you know, kind of coincided 0:18:55.320 --> 0:18:59.800 with drugs, right, not surprisingly. And then there's another one 0:18:59.800 --> 0:19:03.119 that I hadn't heard of, called atmospheric perspective. Had you 0:19:03.160 --> 0:19:07.800 heard of that one? I had not. So. Atmospheric perspective is, um, 0:19:07.840 --> 0:19:10.840 it's basically the dust, particles in the water, vapor in 0:19:10.840 --> 0:19:13.480 the air. The further something is a way, the more 0:19:13.520 --> 0:19:15.920 of an effect those things have on the detail you see. 0:19:15.920 --> 0:19:19.200 If it so your brain says, well, that's a little blurry. Uh, 0:19:19.240 --> 0:19:22.880 that's that's a far away object. And then there's there's 0:19:22.920 --> 0:19:26.560 plenty of other ones, but the gold standard is um 0:19:27.080 --> 0:19:31.480 is object size. Right, that's where you um, you know 0:19:32.080 --> 0:19:34.680 that roughly the size of an object, and you can 0:19:34.760 --> 0:19:37.400 use it to compare to see whether it's it's far 0:19:37.480 --> 0:19:40.440 away or close, depending on whether it's small or large, 0:19:40.600 --> 0:19:42.679 or if you don't know the size of an object, 0:19:42.720 --> 0:19:45.240 but you know two objects are identical and one is 0:19:45.280 --> 0:19:47.479 smaller than the other, well, then you know the smaller 0:19:47.520 --> 0:19:49.720 one is further away. So the brain is like constantly 0:19:49.840 --> 0:19:52.960 using all of these little cues and tricks to put 0:19:53.000 --> 0:19:56.359 together a conception of what it's seeing at any given 0:19:56.400 --> 0:20:00.400 point in time. And then what what um optical allusions 0:20:00.440 --> 0:20:03.919 are are Again these things you can produce to to 0:20:04.040 --> 0:20:07.479 reliably trick the brain into making these wrong decisions. That 0:20:07.480 --> 0:20:12.119 that shows its hand. It reveals how the brain functions 0:20:12.200 --> 0:20:14.840 to take these shortcuts and the tricks that uses. Right, 0:20:14.920 --> 0:20:17.320 Like a brain you think you're so smart, you're really dumb. 0:20:18.240 --> 0:20:22.120 Look at this, and the brain says, oh, stop looking, 0:20:22.280 --> 0:20:26.959 stop looking at those things, look at normal things. Um 0:20:27.040 --> 0:20:30.480 kind of like sorry, I kind of like the apparent 0:20:30.560 --> 0:20:34.119 motion ones, although I can't look at a lot of them. Um, 0:20:34.160 --> 0:20:38.200 those are the ones where something is drawn in such 0:20:38.200 --> 0:20:40.000 a way that it looks like it's moving when it's 0:20:40.040 --> 0:20:43.720 not right. The very famous snake illusion is a great example. 0:20:44.440 --> 0:20:47.160 And you know, this is another one of those theories 0:20:47.200 --> 0:20:49.679 that to me is a little weak. But one of 0:20:49.720 --> 0:20:54.359 the theories is that, um, they're these almost like unnoticeable 0:20:54.640 --> 0:20:57.240 rapid eye movements that we make. Uh how do you 0:20:57.280 --> 0:21:02.800 pronounce that? Yeah, no, s A C C A D 0:21:02.960 --> 0:21:05.760 E s YEA CICADs the cads. I think you could 0:21:05.760 --> 0:21:07.679 probably get away with either one. All right, Well that's 0:21:07.720 --> 0:21:10.399 what they're called. And uh, it's it's like Pruett Taylor 0:21:10.480 --> 0:21:15.240 Vince syndrome. You remember him. Yeah, he's a great actor, 0:21:15.400 --> 0:21:19.000 Yeah he is. Um, so those little movements he usually 0:21:19.000 --> 0:21:21.800 get smoothed out by the brain, so we you know, 0:21:21.920 --> 0:21:25.200 get like a static picture. But um, what it's causing 0:21:25.240 --> 0:21:27.840 in this case is perceiving motion where there was no motion. 0:21:28.680 --> 0:21:30.760 And then the other theory on this one for apparent 0:21:30.840 --> 0:21:34.520 motion illusions is there's just so much information going on 0:21:35.320 --> 0:21:40.160 that uh, you know, there's just confusion. Right. I saw 0:21:40.240 --> 0:21:44.159 one that actually combined the two that that's basically said, Um, 0:21:44.280 --> 0:21:49.439 the the CICADs are creating the illusion of motion, but 0:21:49.640 --> 0:21:52.560 what they're really doing is because the brain is being 0:21:52.640 --> 0:21:55.719 hit with all this visual information that is just totally 0:21:55.760 --> 0:21:59.520 doesn't make sense that we never never happen in nature 0:21:59.560 --> 0:22:03.720 except maybe in motion. That these CICADs actually each time 0:22:03.800 --> 0:22:07.960 your eye makes this tiny movement, it refreshes this overwhelming 0:22:08.640 --> 0:22:13.600 um overload of information onto the brain, which creates the 0:22:13.720 --> 0:22:17.960 sensation of movement. Oh yeah, pretty cool. Well, one of 0:22:18.000 --> 0:22:20.800 the cool aspects of all of this to me is 0:22:21.160 --> 0:22:25.080 um is the fact that once you've once you've seen 0:22:25.760 --> 0:22:30.280 the illusion and the trick to it, you can't undo that, right, 0:22:30.400 --> 0:22:32.720 So the brain is like a, ha, you know, I 0:22:32.840 --> 0:22:35.960 got this one, like you know, the famous one, the 0:22:35.960 --> 0:22:39.320 old lady or the or the young woman, the black 0:22:39.359 --> 0:22:42.560 and white. It's a you know, classic illusion. And once 0:22:42.640 --> 0:22:44.560 you you know, you can stare at and be like, 0:22:44.640 --> 0:22:46.400 I just see the young lady or I just see 0:22:46.440 --> 0:22:49.879 the old lady. Once you've seen both, then your brain 0:22:50.000 --> 0:22:52.200 has like I said, it says ah, and it files 0:22:52.240 --> 0:22:55.320 that away as prior knowledge and a little folder in 0:22:55.359 --> 0:22:58.239 the brain and you can't undo that. So once you've 0:22:58.280 --> 0:23:00.199 seen it, and you've seen the trick. You can aways 0:23:00.240 --> 0:23:02.199 look at it and kind of make that flip in 0:23:02.240 --> 0:23:05.160 your mind, right exactly. And it's the same thing too 0:23:05.200 --> 0:23:08.960 with them contour less figures. Where is it a wine 0:23:09.000 --> 0:23:12.479 goblet or is it two people's faces facing one another? 0:23:12.560 --> 0:23:15.720 Kind of thing? Right? Oh yeah, yeah, yeah, you know 0:23:15.880 --> 0:23:18.560 the negative space. Yeah, And apparently the trick to those 0:23:18.760 --> 0:23:22.199 is you focus on the black or the white and 0:23:22.240 --> 0:23:24.960 you see whichever one appears to be in the foreground, 0:23:25.040 --> 0:23:28.679 because what your brain is doing is saying, um, I 0:23:28.760 --> 0:23:30.600 need a foreground and I need a background, and then 0:23:30.640 --> 0:23:33.480 I've got something to work with, and depending on what 0:23:33.520 --> 0:23:36.399 it's which one it's looking at, it decides this is 0:23:36.440 --> 0:23:38.480 the foreground or this is the background. So it's either 0:23:38.520 --> 0:23:40.960 a wine goblet in the foreground or it's two people's 0:23:41.000 --> 0:23:43.560 faces in the foreground. You know, I wonder if this 0:23:43.680 --> 0:23:46.120 stuff if they know anything about because they didn't see 0:23:46.119 --> 0:23:49.160 anything in the research, but if they know anything that 0:23:49.160 --> 0:23:54.280 that this is like a brain exercise and helps you out, 0:23:55.080 --> 0:23:58.600 like you know, playing suduco or doing word puzzles, or 0:23:58.640 --> 0:24:02.720 if the brain is like stop looking at these, you know, 0:24:03.280 --> 0:24:06.399 I don't like this I can't take anymore, you know, 0:24:06.600 --> 0:24:08.719 or you know, like literally maybe, or if it causes 0:24:08.760 --> 0:24:12.199 stress on the brain by by taxing it in a 0:24:12.200 --> 0:24:15.280 way that it is not accustomed to or doesn't say 0:24:15.240 --> 0:24:17.520 it doesn't like. Obviously the brain doesn't have a you know, 0:24:17.960 --> 0:24:21.600 it's not a little person, but you know what I'm saying. Yeah, no, 0:24:21.680 --> 0:24:24.400 I know what you mean. But the brain, even if 0:24:24.400 --> 0:24:28.240 it's not a little person, it could still not like things. Right, 0:24:28.760 --> 0:24:31.120