WEBVTT - Ep116 " What is Color? Part 2: Why royals wear purple" 0:00:05.000 --> 0:00:08.880 Today's episode is part two about color and the brain. 0:00:09.880 --> 0:00:14.400 Why did royals wear purple? It's not accidental And if 0:00:14.440 --> 0:00:17.800 you rewound history ten thousand years and ran it again, 0:00:17.880 --> 0:00:21.080 you'd find exactly the same outcome. So what's going on? 0:00:21.680 --> 0:00:26.080 And how do we see colors that our recent ancestors 0:00:26.480 --> 0:00:31.080 never saw in their lives? Why can't you imagine a 0:00:31.160 --> 0:00:33.960 new color? Are there, in fact new colors that you 0:00:34.200 --> 0:00:36.520 could see? Yes, and I'm going to show you how 0:00:36.520 --> 0:00:40.040 to do that. Can you lose your color vision? And 0:00:40.080 --> 0:00:42.480 what does any of this have to do with language 0:00:42.560 --> 0:00:46.600 or culture? Or why the military likes color blind people 0:00:46.680 --> 0:00:50.680 for a particular task, and why I suggest that the 0:00:50.680 --> 0:00:57.280 cultural history of Thailand was influenced by one single, unknown neurodivergent. 0:01:00.760 --> 0:01:03.480 Welcome to Dinner Cosmos with me David Eagleman. I'm a 0:01:03.560 --> 0:01:07.120 neuroscientist and author at Stanford and in these episodes we 0:01:07.200 --> 0:01:10.039 look at the world inside us and around us to 0:01:10.240 --> 0:01:14.360 understand why and how our lives look the way they do. 0:01:30.120 --> 0:01:33.880 Today's episode is part two about the absolutely amazing and 0:01:34.040 --> 0:01:38.120 often underappreciated topic of color. And if I do my 0:01:38.280 --> 0:01:40.679 job right, this is going to allow you to see 0:01:40.720 --> 0:01:44.240 the world with totally fresh eyes. So we're going to 0:01:44.319 --> 0:01:46.680 start with a quick catch up from last week so 0:01:46.720 --> 0:01:50.559 we can continue this incredible story about color and the brain. 0:01:50.920 --> 0:01:54.360 Last week, we talked about the fact that color is 0:01:54.520 --> 0:01:57.960 not a property of the physical world, but it's a 0:01:58.080 --> 0:02:02.920 creation of the brain. Color doesn't exist in light itself. 0:02:03.120 --> 0:02:08.640 Light is just electromagnetic radiation of various wavelengths, and our 0:02:08.680 --> 0:02:14.960 brains interpret those wavelengths by constructing the experience of color. 0:02:15.520 --> 0:02:19.960 This private interpretation of color begins in the retina with 0:02:20.040 --> 0:02:24.760 a special type of photoreceptor cones, which detect wavelengths and 0:02:24.919 --> 0:02:28.919 come in three flavors sensitive to short, medium, and long wavelengths, 0:02:29.160 --> 0:02:33.239 which corresponds approximately to red, green, and blue. The brain 0:02:33.360 --> 0:02:38.800 then processes patterns of activation across these cells to produce 0:02:38.880 --> 0:02:42.480 the experience of color, and last week we talked about 0:02:42.520 --> 0:02:47.560 color constancy, which allows us to perceive colors as stable 0:02:47.680 --> 0:02:51.720 despite the changing lighting conditions, something that we see all 0:02:51.760 --> 0:02:56.000 the time in visual illusions. We also talked about evolution. 0:02:56.360 --> 0:03:00.960 For example, we humans have three types of giving us 0:03:01.320 --> 0:03:05.839 trichromatic vision, but this is a rare trait among mammals, 0:03:06.160 --> 0:03:09.840 most of whom are dichromatic, meaning they have two types 0:03:09.840 --> 0:03:13.760 of cones, and this is likely because of a nocturnal 0:03:14.120 --> 0:03:19.000 bottleneck where during the age of dinosaurs, the ancestors of 0:03:19.040 --> 0:03:22.639 mammals how to avoid getting stomped on and eaten, and 0:03:22.720 --> 0:03:26.600 so they scampered around at night and got better night vision, 0:03:27.040 --> 0:03:31.560 but lost some of their color vision. Now humans and 0:03:31.600 --> 0:03:37.520 some other primates reevolved trichromatic vision, possibly not just for 0:03:37.840 --> 0:03:42.760 spotting ripe fruit, but for social reasons, detecting subtle changes 0:03:43.040 --> 0:03:46.880 in skin coloration due to emotions. But in any case, 0:03:47.280 --> 0:03:51.360 lots of our neighbors in the mammalian kingdom can't see 0:03:51.800 --> 0:03:56.680 red and orange, which is why deer hunters wear orange vests, 0:03:56.800 --> 0:03:59.960 because that allows the hunters to see each other clearly, 0:04:00.520 --> 0:04:03.400 but the deer just can't see them. And finally we 0:04:03.440 --> 0:04:06.800 saw how other species like bees and snakes and manta 0:04:06.840 --> 0:04:11.600 shrimp they presumably perceive the world very differently because their 0:04:11.640 --> 0:04:15.480 eyes pick up on ultraviolet light or infrared light or 0:04:15.520 --> 0:04:18.560 polarized light. And if you tune into last week's episode, 0:04:18.560 --> 0:04:21.360 you'll hear lots of other stories about how color serves 0:04:21.720 --> 0:04:26.279 many functions like camouflage or warning or mating signals or 0:04:26.360 --> 0:04:31.000 deception or emotional communication. Now we're ready to continue our 0:04:31.040 --> 0:04:34.560 story this week. So let's start with something that I 0:04:34.560 --> 0:04:38.600 think is amazing, which is that we see so many 0:04:38.640 --> 0:04:43.599 more colors than even our recent ancestors did. This is 0:04:43.640 --> 0:04:46.640 not because of a change in our biology. It's because 0:04:46.680 --> 0:04:51.479 our current collection of technologies can generate so much more. 0:04:52.040 --> 0:04:56.159 For example, your great great grandparents never saw a lot 0:04:56.200 --> 0:05:00.360 of neon, or the bright ultra red of attack esla, 0:05:00.600 --> 0:05:04.160 or the blaze orange of a caution sign on the road. 0:05:04.400 --> 0:05:07.839 But we see these colors all the time. Now I 0:05:07.880 --> 0:05:13.599 want you to try this. Imagine a new color. Go ahead, Okay, 0:05:13.640 --> 0:05:16.039 you can't do it. The fact that you can't do 0:05:16.120 --> 0:05:18.880 it is very revealing, and it's very important because it 0:05:18.960 --> 0:05:23.679 illustrates for us the fence lines of our perceptions, beyond 0:05:23.720 --> 0:05:26.760 which we just can't walk. And by the way, if 0:05:26.760 --> 0:05:29.240 you could envision a new color, you wouldn't be able 0:05:29.320 --> 0:05:33.120 to explain the sensation of it to another person. For example, 0:05:33.279 --> 0:05:37.600 you have to experience purple to know what purple is. 0:05:38.000 --> 0:05:41.520 There's no amount of description on a podcast or in 0:05:41.560 --> 0:05:45.040 a textbook that's ever going to allow a totally color 0:05:45.080 --> 0:05:49.919 blind person to understand purpleness. Here's an analogy, just to 0:05:49.920 --> 0:05:53.919 make this clear, try explaining vision to a friend of 0:05:53.960 --> 0:05:57.320 yours who is born blind. You can try all you want, 0:05:57.720 --> 0:06:00.359 and your blind friend might even pretend to understan what 0:06:00.400 --> 0:06:03.679 you're talking about, but it is a fruitless attempt because 0:06:03.720 --> 0:06:09.600 to understand vision requires experiencing vision. And that's the same 0:06:09.720 --> 0:06:16.039 with experiencing purple or canary yellow or cobalt blue. You 0:06:16.200 --> 0:06:19.040 have to experience it to know it. There's no way 0:06:19.240 --> 0:06:23.200 to describe it. Language is just a way of tagging 0:06:23.600 --> 0:06:27.040 shared experiences, and if it's not shared in some way, 0:06:27.520 --> 0:06:31.960 no amount of language will do the trick. Okay, so 0:06:32.040 --> 0:06:34.000 let's come back to the idea of whether you will 0:06:34.000 --> 0:06:38.599 ever have the chance to see a new color. Well, 0:06:38.600 --> 0:06:41.040 it seems pretty clear that the answer is no, because 0:06:41.080 --> 0:06:45.120 the space of possible colors that humans can see are 0:06:45.120 --> 0:06:49.359 pretty well represented in our world, but under special circumstances 0:06:49.800 --> 0:06:53.400 you can see new ones. So first, let's start with 0:06:53.440 --> 0:06:56.920 what are known as impossible colors. These are colors that 0:06:56.960 --> 0:07:01.400 are outside what our cones can put together. For example, 0:07:01.680 --> 0:07:06.000 you can't have a reddish green or a yellowish blue. 0:07:06.040 --> 0:07:10.040 These are combinations that the visual system just isn't wired 0:07:10.080 --> 0:07:14.520 to perceive simultaneously. But under certain conditions. Using tricks in 0:07:14.560 --> 0:07:18.760 the laboratory, some people do report glimpsing these colors. These 0:07:18.800 --> 0:07:23.760 perceptions are fleeting, but they hint at the boundaries and 0:07:23.840 --> 0:07:27.920 the flexibility of color perception. So here's something that you 0:07:27.920 --> 0:07:31.280 can try easily. Let's say that you stare at a 0:07:31.400 --> 0:07:35.360 square that is cyan in color, and you just stare 0:07:35.400 --> 0:07:37.680 at that for twenty or thirty seconds. Then if you 0:07:37.720 --> 0:07:40.760 look over to a white piece of paper, you'll see 0:07:40.800 --> 0:07:44.920 an orange after image. Okay, fine, but now after staring 0:07:44.960 --> 0:07:48.400 at the cyan, try looking over at an orange piece 0:07:48.440 --> 0:07:52.400 of paper, and you will see what we call hyperbolic orange, 0:07:52.720 --> 0:07:56.120 which is an orange so orange that you never can 0:07:56.200 --> 0:07:59.360 normally see that. Now, there are a bunch of ways 0:07:59.400 --> 0:08:04.000 to see impossible colors. Here's one. Stare at a yellow 0:08:04.080 --> 0:08:06.960 square for a while, and then look at a piece 0:08:06.960 --> 0:08:11.360 of paper that's black. You'll see what is called stygian blue, 0:08:11.760 --> 0:08:16.120 which is a blue that is darker than black. Or 0:08:16.560 --> 0:08:19.960 stare at a green square for a while and then 0:08:20.000 --> 0:08:23.280 look at a white background and you'll see what's called 0:08:23.680 --> 0:08:27.640 self luminous red, a red that is brighter than white. 0:08:28.320 --> 0:08:32.000 These are some ways to see outside the normal fence 0:08:32.040 --> 0:08:34.280 lines of color, and I'll put demos of these on 0:08:34.320 --> 0:08:36.880 the show notes at Eagleman dot com. Now, there are 0:08:37.080 --> 0:08:40.840 other ways to see new colors that require doing so 0:08:40.960 --> 0:08:42.640 in the laboratory, and I'm going to come back to 0:08:42.679 --> 0:08:44.800 that near the end of the episode when I'm going 0:08:44.840 --> 0:08:48.120 to talk about the future of seeing color. But for now, 0:08:48.160 --> 0:08:50.600 I want to mention something else, which is the issue 0:08:50.640 --> 0:08:55.400 of seeing data outside the normal visual spectrum that we 0:08:55.480 --> 0:08:59.079 can see. For example, it might sound impossible to see 0:08:59.120 --> 0:09:02.080 in the altar for violet range, but it turns out 0:09:02.400 --> 0:09:06.360 your photoreceptors can do that. It's just that the lens 0:09:06.440 --> 0:09:10.440 of your eye blocks out UV light. But then something 0:09:10.559 --> 0:09:13.920 was accidentally discovered in the last couple of decades. A 0:09:13.920 --> 0:09:17.199 lot of people go in for cataract surgery and they 0:09:17.200 --> 0:09:22.240 get their lens exchanged for a synthetic replacement. Your natural 0:09:22.320 --> 0:09:26.520 lens blocks UV, but the replacement lens does not, So 0:09:26.600 --> 0:09:31.559 patients found themselves tapping into ranges of the electromagnetic spectrum 0:09:31.760 --> 0:09:34.520 that they couldn't see before. I wrote about one guy 0:09:34.520 --> 0:09:37.080 in my book Live Wire. His name is Alec, and 0:09:37.160 --> 0:09:40.080 he got a lens replacement for his cataracts, and he 0:09:40.160 --> 0:09:42.720 now describes a lot of things that he looks at 0:09:42.760 --> 0:09:46.800 as having a blue violet glow that other people just 0:09:46.840 --> 0:09:49.480 don't see. He noticed this the day after his cataract 0:09:49.520 --> 0:09:53.320 surgery when he was looking at his son's Colorado Rockies shorts. 0:09:53.679 --> 0:09:56.840 Everyone else saw the shorts as black, but he saw 0:09:56.880 --> 0:10:01.080 them with a blue violet sheen. When he put a 0:10:01.240 --> 0:10:03.760 UV filter over his eye to block out the UV, 0:10:04.080 --> 0:10:07.360 he saw them like everyone else. Here's another example. When 0:10:07.360 --> 0:10:09.560 you look at what's called a black light that's turned on, 0:10:09.679 --> 0:10:13.640 you don't see anything, but Alec sees a bright purple glow. 0:10:14.000 --> 0:10:17.720 So this gives him a new superpower, seeing past the 0:10:17.880 --> 0:10:22.560 normal spectrum of colors. Alec has different kinds of experiences 0:10:22.600 --> 0:10:25.920 than we do when he looks at sunsets, or gas 0:10:25.960 --> 0:10:29.559 stoves or flowers. Now I want to flip the question 0:10:29.640 --> 0:10:34.920 to examine the other side. Could you lose your color vision. Yes, 0:10:35.080 --> 0:10:38.360 it's rare, but it happens, and it's called a chromatopsia. 0:10:38.559 --> 0:10:42.679 People with this condition see the world entirely in shades 0:10:42.720 --> 0:10:45.800 of gray, as if life were filmed through the lens 0:10:45.840 --> 0:10:48.240 of an old black and white movie. It's not just 0:10:48.679 --> 0:10:52.800 muted color or red green confusion. It's the complete absence 0:10:52.880 --> 0:10:56.480 of color perception. Just imagine this, The vibrant world that 0:10:56.520 --> 0:10:59.319 we all take for granted gets rendered by your brain 0:10:59.640 --> 0:11:04.000 in a perpetual gray scale, where even a rainbow is 0:11:04.080 --> 0:11:06.880 just a smooth gradient of light and dark. Now, the 0:11:06.920 --> 0:11:09.600 thing I want to note is that achromatopsia results from 0:11:09.679 --> 0:11:13.720 brain damage, specifically to a region called area V four 0:11:13.840 --> 0:11:17.679 in the visual cortex. Because color vision doesn't happen in 0:11:17.720 --> 0:11:21.240 your eyes alone. While the cone cells in your retina 0:11:21.320 --> 0:11:25.640 detects different wavelengths of light, the experience of color is 0:11:25.679 --> 0:11:29.040 assembled in the brain, and one of the key regions 0:11:29.080 --> 0:11:33.920 responsible for putting those wavelengths together into color perception is 0:11:33.960 --> 0:11:36.640 this area of V four, located in what's known as 0:11:36.640 --> 0:11:39.680 the ventral visual pathway in the brain. The point is, 0:11:39.920 --> 0:11:44.480 if this area is damaged from a stroke, from head trauma, 0:11:44.559 --> 0:11:49.240 from a brain tumor, the person gets this cortical color blindness. 0:11:49.320 --> 0:11:52.600 The eyes are perfectly healthy, but the brain can't interpret 0:11:52.960 --> 0:11:57.959 color signals anymore, so the person experiences the world in grayscale. 0:11:58.240 --> 0:12:01.520 So this once again illustrates the simple but critical point 0:12:01.720 --> 0:12:05.120 that color is a construction of the brain, and you 0:12:05.240 --> 0:12:08.160 have to have all the right pieces and parts running 0:12:08.360 --> 0:12:11.440 or else. You can see just fine, but you can't 0:12:11.480 --> 0:12:32.000 see color. Now. Some people, of course, are born color blind, 0:12:32.080 --> 0:12:34.760 but not because of brain damage, but instead because they 0:12:34.760 --> 0:12:38.480 don't have some of the types of cones in their eye. 0:12:38.760 --> 0:12:41.520 As a reminder, most people are born with three different 0:12:41.559 --> 0:12:44.760 types of cones color photo receptors, but some people are 0:12:44.760 --> 0:12:48.320 born with only two types, or one type or none, 0:12:48.600 --> 0:12:54.560 giving them a diminished or no ability to distinguish between colors. Now, 0:12:54.679 --> 0:12:59.839 the military excludes colorblind soldiers from certain jobs, but they 0:12:59.840 --> 0:13:03.160 have come to realize that colorblind people do have a 0:13:03.280 --> 0:13:09.040 secret superpower. They can spot enemy camouflage better than people 0:13:09.080 --> 0:13:14.120 with normal color vision. Why because they're better at distinguishing 0:13:14.200 --> 0:13:17.760 between shades of gray. This is because they have the 0:13:17.800 --> 0:13:20.439 same amount of visual cortex at the back of their brain, 0:13:20.840 --> 0:13:24.360 but fewer color dimensions to worry about. So they're using 0:13:24.400 --> 0:13:28.280 the same cortical territory, but for a simpler task, just 0:13:28.400 --> 0:13:31.720 gray scale instead of color, and this gives them improved 0:13:31.800 --> 0:13:37.520 performance in distinguishing very subtle differences in brightness. So although 0:13:37.600 --> 0:13:39.760 it would be a real bummer to be colorblind, there 0:13:39.800 --> 0:13:43.680 are some advantages as well. So now let's return to color. 0:13:43.800 --> 0:13:46.280 Everything we've talked about so far as a reminder that 0:13:46.400 --> 0:13:50.720 color is not just about the electromagnetic radiation hitting the eye, 0:13:51.080 --> 0:13:54.520 but about what happens in the brain. And one very 0:13:54.520 --> 0:13:58.640 good example of that is something I've talked about before, synesthesia. 0:13:59.120 --> 0:14:03.240 This is a brain phenomenon in which color blurs with 0:14:03.400 --> 0:14:08.160 different concept a typical citisteit will perceive letters or numbers 0:14:08.080 --> 0:14:12.400 as having fixed colors, like a is always red, or 0:14:12.800 --> 0:14:16.319 the number seven is ce foam green, and it can 0:14:16.360 --> 0:14:20.840 commonly be with weekdays or months like Wednesday is indigo 0:14:20.880 --> 0:14:24.720 blue or August is yellow. Now it's not a hallucination, 0:14:25.520 --> 0:14:28.120 but to the person, it's just self evidently true that 0:14:28.120 --> 0:14:31.960 that's what that letter or number or weekday or month is. 0:14:32.400 --> 0:14:35.240 Of course it's purple or yellow or green. So I've 0:14:35.280 --> 0:14:37.920 studied synesthesia in my lab for many years because it's 0:14:37.960 --> 0:14:42.560 such a good inroad into conscious experience and also the 0:14:42.600 --> 0:14:46.800 differences between one person's experience and another's, and the difference 0:14:46.880 --> 0:14:51.440 is between people's experiences on the inside when they're perceiving 0:14:51.480 --> 0:14:54.560 the world. If you're interested in synesthesia, please listen to 0:14:54.720 --> 0:14:57.480 episode four. But for now, I want to zoom in 0:14:57.520 --> 0:15:01.960 on the issue of colored weekdays, which is a common form. 0:15:02.280 --> 0:15:04.640 The thing I want to emphasize is that the color 0:15:04.680 --> 0:15:08.680 palette ends up being different for each cynisthees. So one 0:15:08.760 --> 0:15:13.000 person might say, oh, Monday is clearly green and Tuesday 0:15:13.200 --> 0:15:17.160 is purple, and Wednesday is yellow, and a different cinisthee 0:15:17.440 --> 0:15:21.440 has a different color palette. Now, I've studied literally thousands 0:15:21.480 --> 0:15:24.800 of such cynthtes, but here's something I just learned that 0:15:25.000 --> 0:15:28.920 really surprised me. I learned that in Thailand there's an 0:15:29.000 --> 0:15:32.440 ancient tradition in which each day of the week has 0:15:32.480 --> 0:15:38.280 a corresponding color, rooted in Hindu based astrology. So Monday 0:15:38.480 --> 0:15:43.080 is yellow, Tuesday is pink, Wednesday is green, and so on. 0:15:43.520 --> 0:15:48.120 Apparently these colors are tied to planetary deities like Mars, 0:15:48.120 --> 0:15:53.360 for Tuesday is associated with pink, Mercury, for Wednesday is green, 0:15:53.800 --> 0:15:57.320 and so on, and traditionally it was believed to bring 0:15:57.520 --> 0:16:00.640 luck if you wore that color or use color on 0:16:00.760 --> 0:16:03.680 the corresponding day. This apparently used to be very common 0:16:03.680 --> 0:16:06.880 in Thailand to wear the right color every single day. 0:16:06.920 --> 0:16:09.280 Today it's a little less common. Now. You can probably 0:16:09.280 --> 0:16:11.440 guess what I'm wondering about, which is where did this 0:16:11.600 --> 0:16:15.440 colored weekday idea come from Well, if you consult any 0:16:15.560 --> 0:16:17.720 Taie book on this, they'll say it comes from the 0:16:18.080 --> 0:16:22.600 colors of their deities. But of course gods don't really exist, 0:16:22.680 --> 0:16:26.239 and if they did, it's not obvious they would have colors, 0:16:26.360 --> 0:16:29.280 or that anyone would have seen those colors. So my 0:16:29.360 --> 0:16:32.240 suspicion is that if we really did get to the 0:16:32.280 --> 0:16:36.360 bottom of this very ancient history, we'd find a very 0:16:36.440 --> 0:16:41.400 influential Cinistheite at bottom, someone who said, well, of course 0:16:41.400 --> 0:16:44.440 Tuesday is pink and Wednesday is green and so on, 0:16:44.680 --> 0:16:49.200 and because of some cult of personality, it stuck, and 0:16:49.280 --> 0:16:53.040 millennia later, kids are still told that this deity is 0:16:53.080 --> 0:16:55.040 this color, so that day is the color and you 0:16:55.040 --> 0:16:58.560 should wear that shirt. And so, like all stories with 0:16:58.640 --> 0:17:03.320 cultural momentum, people accept it. Why because everyone else accepts 0:17:03.360 --> 0:17:05.879 it and for thousands of years, So there must be 0:17:05.920 --> 0:17:09.400 something to it. But that's something I suggest is a 0:17:09.560 --> 0:17:16.639 single influential Cynistheide whose quirky neural network determined what everyone 0:17:16.760 --> 0:17:20.359 wore for hundreds of generations. So if you ever think 0:17:20.480 --> 0:17:24.880 neuroscience doesn't affect culture, take that. And on that topic 0:17:24.960 --> 0:17:27.440 of the intersection between neuroscience and culture, I want to 0:17:27.520 --> 0:17:30.919 zoom the camera out to see what happens when lots 0:17:30.920 --> 0:17:34.800 of humans start talking together about color. So we're going 0:17:34.880 --> 0:17:39.240 to turn now to language. For most listeners of this podcast, 0:17:39.320 --> 0:17:44.200 we look at a rainbow and divide it into red, orange, yellow, green, blue, indigo, violet. 0:17:44.480 --> 0:17:47.680 But not every culture divides the spectrum the same way 0:17:47.880 --> 0:17:51.720 or sees the same number of colors. In some languages, 0:17:51.800 --> 0:17:56.080 there is no distinct word for blue. In other languages, 0:17:56.200 --> 0:17:59.359 green and blue are considered shades of the same color. 0:17:59.560 --> 0:18:02.760 As an example of the kinds of differences here, the 0:18:02.960 --> 0:18:07.680 Himba people of Namibia group colors differently from English speakers. 0:18:07.720 --> 0:18:11.000 They have multiple words for what we call green and 0:18:11.240 --> 0:18:15.080 none for what we call blue. Even ancient texts reveal 0:18:15.240 --> 0:18:20.439 this difference in color vocabularies, So in Homer's Odyssey, the 0:18:20.520 --> 0:18:23.480 sea is never described as blue, but it's described as 0:18:23.680 --> 0:18:28.080 wine dark. Scholars have long puzzled over this poetic phrase. 0:18:28.480 --> 0:18:30.720 Was it a metaphor or was it that the ancient 0:18:30.800 --> 0:18:35.119 Greeks didn't categorize blue the way that we do. Blue 0:18:35.160 --> 0:18:38.879 appears almost nowhere in ancient Greek language, and where it 0:18:38.960 --> 0:18:43.280 does is often ambiguous. Why while in ancient Greece there 0:18:43.280 --> 0:18:46.840 were few blue dyes or paints, and by the way, 0:18:46.880 --> 0:18:50.679 blue animals are extraordinarily rare in nature. So while the 0:18:50.880 --> 0:18:55.119 Egyptians used a synthetic pigment, which we call Egyptian blue, 0:18:55.480 --> 0:18:59.000 the Greeks didn't use or produce blue. So it meant 0:18:59.040 --> 0:19:02.280 that blue was less present in their daily life, or 0:19:02.320 --> 0:19:04.840 in their clothing or in their art, and the thought 0:19:04.920 --> 0:19:08.520 goes that it was therefore less common in the language, 0:19:08.600 --> 0:19:10.919 in the same way that cultures on the equator have 0:19:11.119 --> 0:19:16.000 fewer words for distinguishing types of snow than do northern cultures. 0:19:16.359 --> 0:19:19.480 Now zooming out a moment, there were two researchers, Berlin 0:19:19.640 --> 0:19:23.560 and k who proposed that even though language might have 0:19:23.720 --> 0:19:27.560 different color terms, they all follow a predictable order in 0:19:27.600 --> 0:19:30.680 the development of these terms. In other words, the first 0:19:30.680 --> 0:19:34.160 two terms to appear historically in any language are always 0:19:34.359 --> 0:19:38.560 black and white or dark and light. Then comes red. 0:19:39.359 --> 0:19:42.399 Then when cultures get more culture as they introduce green 0:19:42.600 --> 0:19:45.800 or yellow. Only later do you get things like blue 0:19:46.160 --> 0:19:50.080 and brown and more nuanced shades like pink or orange. 0:19:50.640 --> 0:19:55.199 The hypothesis is that this progression matches the salience of 0:19:55.280 --> 0:19:58.840 colors in the environment. The contrast of light and dark 0:19:59.160 --> 0:20:02.919 is really important, the presence of blood, the ripeness of fruit, 0:20:03.320 --> 0:20:06.600 the necessity of distinguishing between plants. So it's only when 0:20:06.640 --> 0:20:10.679 society has become more complex and encounter more dyes and 0:20:10.840 --> 0:20:16.000 materials and artistic traditions then you get new color terms emerging. 0:20:16.280 --> 0:20:19.680 So different languages have different color terms, and one idea 0:20:19.760 --> 0:20:23.560 that has emerged is called linguistic relativity, which is this 0:20:23.680 --> 0:20:27.560 notion that the language that you speak shapes how you 0:20:27.680 --> 0:20:31.119 perceive the world. The idea is that although all people 0:20:31.160 --> 0:20:35.679 can see blue, if your language doesn't label it distinctly, 0:20:36.080 --> 0:20:38.399 you might not really pay attention to it as a 0:20:38.440 --> 0:20:42.480 separate category. And this is indeed what a lot of 0:20:42.720 --> 0:20:46.680 cognitive science studies have found. Your language shapes at least 0:20:46.720 --> 0:20:50.920 a little bit your color distinctions. For example, the Russian 0:20:51.000 --> 0:20:54.879 language has distinct words for light blue and dark blue, 0:20:55.160 --> 0:20:59.159 and when Russians are tested on their ability to distinguish 0:20:59.400 --> 0:21:03.320 shades of blue, they're faster at spotting the difference between 0:21:03.440 --> 0:21:06.880 light and dark blues than English speakers, who use one 0:21:06.880 --> 0:21:11.159 word for both blue. In other words, Russian speaking brains 0:21:11.640 --> 0:21:16.080 process the difference more quickly, suggesting that having a word 0:21:16.200 --> 0:21:19.640 for something helps you see it. If your language has 0:21:19.640 --> 0:21:23.440 more precise blue terms, like Russian, you can distinguish shades 0:21:23.480 --> 0:21:27.080 faster than languages that don't, like English, and you can 0:21:27.119 --> 0:21:30.240 see the same story in babies. Infants can see color 0:21:30.320 --> 0:21:33.560 long before they learn to speak, but once they acquire 0:21:33.640 --> 0:21:39.600 the words for specific colors, their ability to distinguish them improves. 0:21:40.440 --> 0:21:46.160 Language tunes the brain to attend to specific aspects of 0:21:46.200 --> 0:21:49.399 the scene. So if the Greeks didn't have a strong 0:21:49.440 --> 0:21:52.520 word for blue, they might have grouped it with other 0:21:52.600 --> 0:21:56.200 colors like green or gray and not really noticed it 0:21:56.240 --> 0:21:59.919 as blue. The Greeks didn't lack the ability to see blue, 0:22:00.480 --> 0:22:03.280 but in their culture they didn't isolate it with language, 0:22:03.760 --> 0:22:07.480 likely because blue was rare in their environment and their 0:22:07.560 --> 0:22:11.719 language hadn't evolved to distinguish it clearly. So when Homer 0:22:11.840 --> 0:22:15.560 describes the sea as wine dark, it's not because he 0:22:15.640 --> 0:22:19.199 was colorblind. It's because the way his culture saw and 0:22:19.320 --> 0:22:22.480 named colors was a little different from ours. And by 0:22:22.520 --> 0:22:24.560 the way this issue about the Greeks and blue, the 0:22:24.560 --> 0:22:28.359 same is true of many ancient languages, including Hebrew and 0:22:28.480 --> 0:22:31.800 Chinese and Japanese, and in modern studies we can look 0:22:31.840 --> 0:22:34.680 at the Himba people who as I mentioned have multiple 0:22:34.680 --> 0:22:39.000 words for green and none for blue. In experiments, they 0:22:39.000 --> 0:22:43.639 can easily distinguish green shades that we Westerners struggle to 0:22:43.680 --> 0:22:46.640 tell apart, but they find it difficult to pick out 0:22:46.680 --> 0:22:50.480 a blue square from a field of green. Now we've 0:22:50.520 --> 0:22:54.639 been talking about biology and language, but what's fascinating is 0:22:54.680 --> 0:22:59.439 how this private phenomenon of color takes on cultural meaning. 0:22:59.800 --> 0:23:03.520 A million examples of this. I'll just do a quick whistlestop, TORP. 0:23:03.600 --> 0:23:06.000 So just look at the way we organize our world 0:23:06.119 --> 0:23:08.600 through color. We have red states and blue states. We 0:23:08.680 --> 0:23:12.159 have green energy, we have black markets, we have white lies. 0:23:12.680 --> 0:23:18.320 Color becomes shorthand for complex social and political ideas. Even 0:23:18.359 --> 0:23:22.480 our moral frameworks become color coded. You've got the white 0:23:22.480 --> 0:23:24.760 hat and the black hat, and the old Westerns. You've 0:23:24.760 --> 0:23:27.160 got the white dove of peace, you have the red 0:23:27.280 --> 0:23:30.880 devil of temptation. And colors very commonly come to signal 0:23:31.000 --> 0:23:35.560 identity and allegiance. You have teams and uniforms that define 0:23:35.720 --> 0:23:40.520 us versus them by color. Movements adopt symbolic palettes. So 0:23:40.560 --> 0:23:44.600 the Suffragettes wore white and green and violet. AIDS awareness 0:23:44.680 --> 0:23:49.560 uses red, environmental causes green. You see rainbow flags and 0:23:49.680 --> 0:23:54.159 pride parades. You see orange worn by anti gun violence advocates. 0:23:54.440 --> 0:23:57.119 So in this way, when we look around, we see 0:23:57.160 --> 0:24:01.640 that color comes to serve as a quick symbol flag. Now, 0:24:01.680 --> 0:24:06.240 not surprisingly, there's nothing fundamental about these associations and therefore 0:24:06.600 --> 0:24:10.960 they aren't static. So in the eighteen hundreds, pink was 0:24:11.000 --> 0:24:16.080 considered a strong masculine color related to red. Blue was 0:24:16.119 --> 0:24:20.199 seen as delicate and feminine. These meanings flipped in the 0:24:20.240 --> 0:24:22.879 twentieth century, and it had to do with shifts in 0:24:22.960 --> 0:24:28.360 fashion and marketing and cultural signaling. Color, like language, evolves 0:24:28.560 --> 0:24:32.040 and political colors vary. So you've got red for the 0:24:32.200 --> 0:24:35.679 left in Europe, blue for conservatives in the UK, and 0:24:35.760 --> 0:24:38.440 it's reversed in the United States. What I recently read 0:24:38.480 --> 0:24:40.919 is that the colors in the United States blue for 0:24:41.040 --> 0:24:45.000 liberals and red for conservatives. This got nailed down just 0:24:45.119 --> 0:24:48.520 around the year two thousand, when the major television networks 0:24:48.560 --> 0:24:52.600 started using this as a visual shorthand for liberal and conservative, 0:24:52.880 --> 0:24:56.800 and that's how it got crystallized into public consciousness. I 0:24:56.800 --> 0:24:59.000 don't really know the history of this, but I suspect 0:24:59.359 --> 0:25:02.359 then in the day decades of black and white newspapers, 0:25:02.720 --> 0:25:05.560 it was easier to use a donkey and an elephant 0:25:05.640 --> 0:25:09.320 to distinguish the parties. And only when color television became 0:25:09.440 --> 0:25:14.520 ubiquitous did it make sense to introduce a quick color flag. Okay, So, 0:25:14.560 --> 0:25:18.320 now coming back to cultural messages, what is conveyed by 0:25:18.359 --> 0:25:23.400 a color depends on your local context. In Western traditions, 0:25:23.760 --> 0:25:27.679 white is associated with purity and innocence and weddings, but 0:25:27.760 --> 0:25:31.880 in many Eastern cultures, white symbolizes death and is worn 0:25:31.960 --> 0:25:36.119 by mourners. In South Africa, red can be a color 0:25:36.160 --> 0:25:40.760 of mourning. In Brazil, purple is reserved for funerals. I'll 0:25:40.760 --> 0:25:44.040 give you another example. Red, which in the West can 0:25:44.080 --> 0:25:48.840 symbolize danger or passion, is associated in China with celebration 0:25:49.000 --> 0:25:52.400 and joy and luck. A bride in India might wear 0:25:52.480 --> 0:25:56.080 a bright red sorry, while a Western bride walks down 0:25:56.080 --> 0:25:58.600 the aisle in white. So the point here is that 0:25:58.840 --> 0:26:03.240 cultural colors symbols are learned. They're not innate. They are 0:26:03.280 --> 0:26:24.680 built from shared stories and traditions and rituals. Now, despite 0:26:24.720 --> 0:26:28.520 this variation, as far as what color means what sometimes, 0:26:28.840 --> 0:26:31.280 there is a logic to it. Now, one thing I've 0:26:31.280 --> 0:26:36.240 always found fascinating is that purple is always associated with royalty. 0:26:36.640 --> 0:26:40.400 Why purple, why not orange or yellow or something else. Well, 0:26:40.400 --> 0:26:43.600 it turns out that started in ancient Rome with a 0:26:43.800 --> 0:26:47.240 die called Tyrian purple. This was a deep hue and 0:26:47.280 --> 0:26:50.000 it was unlike any other dye that was available at 0:26:50.040 --> 0:26:54.120 the time, and the color became irreversibly associated in their 0:26:54.160 --> 0:26:59.200 society with nobility and wealth and the divine aura of emperors. 0:26:59.400 --> 0:27:03.040