1 00:00:05,000 --> 00:00:08,880 Speaker 1: Today's episode is part two about color and the brain. 2 00:00:09,880 --> 00:00:14,400 Speaker 1: Why did royals wear purple? It's not accidental And if 3 00:00:14,440 --> 00:00:17,800 Speaker 1: you rewound history ten thousand years and ran it again, 4 00:00:17,880 --> 00:00:21,080 Speaker 1: you'd find exactly the same outcome. So what's going on? 5 00:00:21,680 --> 00:00:26,080 Speaker 1: And how do we see colors that our recent ancestors 6 00:00:26,480 --> 00:00:31,080 Speaker 1: never saw in their lives? Why can't you imagine a 7 00:00:31,160 --> 00:00:33,960 Speaker 1: new color? Are there, in fact new colors that you 8 00:00:34,200 --> 00:00:36,520 Speaker 1: could see? Yes, and I'm going to show you how 9 00:00:36,520 --> 00:00:40,040 Speaker 1: to do that. Can you lose your color vision? And 10 00:00:40,080 --> 00:00:42,480 Speaker 1: what does any of this have to do with language 11 00:00:42,560 --> 00:00:46,600 Speaker 1: or culture? Or why the military likes color blind people 12 00:00:46,680 --> 00:00:50,680 Speaker 1: for a particular task, and why I suggest that the 13 00:00:50,680 --> 00:00:57,280 Speaker 1: cultural history of Thailand was influenced by one single, unknown neurodivergent. 14 00:01:00,760 --> 00:01:03,480 Speaker 1: Welcome to Dinner Cosmos with me David Eagleman. I'm a 15 00:01:03,560 --> 00:01:07,120 Speaker 1: neuroscientist and author at Stanford and in these episodes we 16 00:01:07,200 --> 00:01:10,039 Speaker 1: look at the world inside us and around us to 17 00:01:10,240 --> 00:01:14,360 Speaker 1: understand why and how our lives look the way they do. 18 00:01:30,120 --> 00:01:33,880 Speaker 1: Today's episode is part two about the absolutely amazing and 19 00:01:34,040 --> 00:01:38,120 Speaker 1: often underappreciated topic of color. And if I do my 20 00:01:38,280 --> 00:01:40,679 Speaker 1: job right, this is going to allow you to see 21 00:01:40,720 --> 00:01:44,240 Speaker 1: the world with totally fresh eyes. So we're going to 22 00:01:44,319 --> 00:01:46,680 Speaker 1: start with a quick catch up from last week so 23 00:01:46,720 --> 00:01:50,559 Speaker 1: we can continue this incredible story about color and the brain. 24 00:01:50,920 --> 00:01:54,360 Speaker 1: Last week, we talked about the fact that color is 25 00:01:54,520 --> 00:01:57,960 Speaker 1: not a property of the physical world, but it's a 26 00:01:58,080 --> 00:02:02,920 Speaker 1: creation of the brain. Color doesn't exist in light itself. 27 00:02:03,120 --> 00:02:08,640 Speaker 1: Light is just electromagnetic radiation of various wavelengths, and our 28 00:02:08,680 --> 00:02:14,960 Speaker 1: brains interpret those wavelengths by constructing the experience of color. 29 00:02:15,520 --> 00:02:19,960 Speaker 1: This private interpretation of color begins in the retina with 30 00:02:20,040 --> 00:02:24,760 Speaker 1: a special type of photoreceptor cones, which detect wavelengths and 31 00:02:24,919 --> 00:02:28,919 Speaker 1: come in three flavors sensitive to short, medium, and long wavelengths, 32 00:02:29,160 --> 00:02:33,239 Speaker 1: which corresponds approximately to red, green, and blue. The brain 33 00:02:33,360 --> 00:02:38,800 Speaker 1: then processes patterns of activation across these cells to produce 34 00:02:38,880 --> 00:02:42,480 Speaker 1: the experience of color, and last week we talked about 35 00:02:42,520 --> 00:02:47,560 Speaker 1: color constancy, which allows us to perceive colors as stable 36 00:02:47,680 --> 00:02:51,720 Speaker 1: despite the changing lighting conditions, something that we see all 37 00:02:51,760 --> 00:02:56,000 Speaker 1: the time in visual illusions. We also talked about evolution. 38 00:02:56,360 --> 00:03:00,960 Speaker 1: For example, we humans have three types of giving us 39 00:03:01,320 --> 00:03:05,839 Speaker 1: trichromatic vision, but this is a rare trait among mammals, 40 00:03:06,160 --> 00:03:09,840 Speaker 1: most of whom are dichromatic, meaning they have two types 41 00:03:09,840 --> 00:03:13,760 Speaker 1: of cones, and this is likely because of a nocturnal 42 00:03:14,120 --> 00:03:19,000 Speaker 1: bottleneck where during the age of dinosaurs, the ancestors of 43 00:03:19,040 --> 00:03:22,639 Speaker 1: mammals how to avoid getting stomped on and eaten, and 44 00:03:22,720 --> 00:03:26,600 Speaker 1: so they scampered around at night and got better night vision, 45 00:03:27,040 --> 00:03:31,560 Speaker 1: but lost some of their color vision. Now humans and 46 00:03:31,600 --> 00:03:37,520 Speaker 1: some other primates reevolved trichromatic vision, possibly not just for 47 00:03:37,840 --> 00:03:42,760 Speaker 1: spotting ripe fruit, but for social reasons, detecting subtle changes 48 00:03:43,040 --> 00:03:46,880 Speaker 1: in skin coloration due to emotions. But in any case, 49 00:03:47,280 --> 00:03:51,360 Speaker 1: lots of our neighbors in the mammalian kingdom can't see 50 00:03:51,800 --> 00:03:56,680 Speaker 1: red and orange, which is why deer hunters wear orange vests, 51 00:03:56,800 --> 00:03:59,960 Speaker 1: because that allows the hunters to see each other clearly, 52 00:04:00,520 --> 00:04:03,400 Speaker 1: but the deer just can't see them. And finally we 53 00:04:03,440 --> 00:04:06,800 Speaker 1: saw how other species like bees and snakes and manta 54 00:04:06,840 --> 00:04:11,600 Speaker 1: shrimp they presumably perceive the world very differently because their 55 00:04:11,640 --> 00:04:15,480 Speaker 1: eyes pick up on ultraviolet light or infrared light or 56 00:04:15,520 --> 00:04:18,560 Speaker 1: polarized light. And if you tune into last week's episode, 57 00:04:18,560 --> 00:04:21,360 Speaker 1: you'll hear lots of other stories about how color serves 58 00:04:21,720 --> 00:04:26,279 Speaker 1: many functions like camouflage or warning or mating signals or 59 00:04:26,360 --> 00:04:31,000 Speaker 1: deception or emotional communication. Now we're ready to continue our 60 00:04:31,040 --> 00:04:34,560 Speaker 1: story this week. So let's start with something that I 61 00:04:34,560 --> 00:04:38,600 Speaker 1: think is amazing, which is that we see so many 62 00:04:38,640 --> 00:04:43,599 Speaker 1: more colors than even our recent ancestors did. This is 63 00:04:43,640 --> 00:04:46,640 Speaker 1: not because of a change in our biology. It's because 64 00:04:46,680 --> 00:04:51,479 Speaker 1: our current collection of technologies can generate so much more. 65 00:04:52,040 --> 00:04:56,159 Speaker 1: For example, your great great grandparents never saw a lot 66 00:04:56,200 --> 00:05:00,360 Speaker 1: of neon, or the bright ultra red of attack esla, 67 00:05:00,600 --> 00:05:04,160 Speaker 1: or the blaze orange of a caution sign on the road. 68 00:05:04,400 --> 00:05:07,839 Speaker 1: But we see these colors all the time. Now I 69 00:05:07,880 --> 00:05:13,599 Speaker 1: want you to try this. Imagine a new color. Go ahead, Okay, 70 00:05:13,640 --> 00:05:16,039 Speaker 1: you can't do it. The fact that you can't do 71 00:05:16,120 --> 00:05:18,880 Speaker 1: it is very revealing, and it's very important because it 72 00:05:18,960 --> 00:05:23,679 Speaker 1: illustrates for us the fence lines of our perceptions, beyond 73 00:05:23,720 --> 00:05:26,760 Speaker 1: which we just can't walk. And by the way, if 74 00:05:26,760 --> 00:05:29,240 Speaker 1: you could envision a new color, you wouldn't be able 75 00:05:29,320 --> 00:05:33,120 Speaker 1: to explain the sensation of it to another person. For example, 76 00:05:33,279 --> 00:05:37,600 Speaker 1: you have to experience purple to know what purple is. 77 00:05:38,000 --> 00:05:41,520 Speaker 1: There's no amount of description on a podcast or in 78 00:05:41,560 --> 00:05:45,040 Speaker 1: a textbook that's ever going to allow a totally color 79 00:05:45,080 --> 00:05:49,919 Speaker 1: blind person to understand purpleness. Here's an analogy, just to 80 00:05:49,920 --> 00:05:53,919 Speaker 1: make this clear, try explaining vision to a friend of 81 00:05:53,960 --> 00:05:57,320 Speaker 1: yours who is born blind. You can try all you want, 82 00:05:57,720 --> 00:06:00,359 Speaker 1: and your blind friend might even pretend to understan what 83 00:06:00,400 --> 00:06:03,679 Speaker 1: you're talking about, but it is a fruitless attempt because 84 00:06:03,720 --> 00:06:09,600 Speaker 1: to understand vision requires experiencing vision. And that's the same 85 00:06:09,720 --> 00:06:16,039 Speaker 1: with experiencing purple or canary yellow or cobalt blue. You 86 00:06:16,200 --> 00:06:19,040 Speaker 1: have to experience it to know it. There's no way 87 00:06:19,240 --> 00:06:23,200 Speaker 1: to describe it. Language is just a way of tagging 88 00:06:23,600 --> 00:06:27,040 Speaker 1: shared experiences, and if it's not shared in some way, 89 00:06:27,520 --> 00:06:31,960 Speaker 1: no amount of language will do the trick. Okay, so 90 00:06:32,040 --> 00:06:34,000 Speaker 1: let's come back to the idea of whether you will 91 00:06:34,000 --> 00:06:38,599 Speaker 1: ever have the chance to see a new color. Well, 92 00:06:38,600 --> 00:06:41,040 Speaker 1: it seems pretty clear that the answer is no, because 93 00:06:41,080 --> 00:06:45,120 Speaker 1: the space of possible colors that humans can see are 94 00:06:45,120 --> 00:06:49,359 Speaker 1: pretty well represented in our world, but under special circumstances 95 00:06:49,800 --> 00:06:53,400 Speaker 1: you can see new ones. So first, let's start with 96 00:06:53,440 --> 00:06:56,920 Speaker 1: what are known as impossible colors. These are colors that 97 00:06:56,960 --> 00:07:01,400 Speaker 1: are outside what our cones can put together. For example, 98 00:07:01,680 --> 00:07:06,000 Speaker 1: you can't have a reddish green or a yellowish blue. 99 00:07:06,040 --> 00:07:10,040 Speaker 1: These are combinations that the visual system just isn't wired 100 00:07:10,080 --> 00:07:14,520 Speaker 1: to perceive simultaneously. But under certain conditions. Using tricks in 101 00:07:14,560 --> 00:07:18,760 Speaker 1: the laboratory, some people do report glimpsing these colors. These 102 00:07:18,800 --> 00:07:23,760 Speaker 1: perceptions are fleeting, but they hint at the boundaries and 103 00:07:23,840 --> 00:07:27,920 Speaker 1: the flexibility of color perception. So here's something that you 104 00:07:27,920 --> 00:07:31,280 Speaker 1: can try easily. Let's say that you stare at a 105 00:07:31,400 --> 00:07:35,360 Speaker 1: square that is cyan in color, and you just stare 106 00:07:35,400 --> 00:07:37,680 Speaker 1: at that for twenty or thirty seconds. Then if you 107 00:07:37,720 --> 00:07:40,760 Speaker 1: look over to a white piece of paper, you'll see 108 00:07:40,800 --> 00:07:44,920 Speaker 1: an orange after image. Okay, fine, but now after staring 109 00:07:44,960 --> 00:07:48,400 Speaker 1: at the cyan, try looking over at an orange piece 110 00:07:48,440 --> 00:07:52,400 Speaker 1: of paper, and you will see what we call hyperbolic orange, 111 00:07:52,720 --> 00:07:56,120 Speaker 1: which is an orange so orange that you never can 112 00:07:56,200 --> 00:07:59,360 Speaker 1: normally see that. Now, there are a bunch of ways 113 00:07:59,400 --> 00:08:04,000 Speaker 1: to see impossible colors. Here's one. Stare at a yellow 114 00:08:04,080 --> 00:08:06,960 Speaker 1: square for a while, and then look at a piece 115 00:08:06,960 --> 00:08:11,360 Speaker 1: of paper that's black. You'll see what is called stygian blue, 116 00:08:11,760 --> 00:08:16,120 Speaker 1: which is a blue that is darker than black. Or 117 00:08:16,560 --> 00:08:19,960 Speaker 1: stare at a green square for a while and then 118 00:08:20,000 --> 00:08:23,280 Speaker 1: look at a white background and you'll see what's called 119 00:08:23,680 --> 00:08:27,640 Speaker 1: self luminous red, a red that is brighter than white. 120 00:08:28,320 --> 00:08:32,000 Speaker 1: These are some ways to see outside the normal fence 121 00:08:32,040 --> 00:08:34,280 Speaker 1: lines of color, and I'll put demos of these on 122 00:08:34,320 --> 00:08:36,880 Speaker 1: the show notes at Eagleman dot com. Now, there are 123 00:08:37,080 --> 00:08:40,840 Speaker 1: other ways to see new colors that require doing so 124 00:08:40,960 --> 00:08:42,640 Speaker 1: in the laboratory, and I'm going to come back to 125 00:08:42,679 --> 00:08:44,800 Speaker 1: that near the end of the episode when I'm going 126 00:08:44,840 --> 00:08:48,120 Speaker 1: to talk about the future of seeing color. But for now, 127 00:08:48,160 --> 00:08:50,600 Speaker 1: I want to mention something else, which is the issue 128 00:08:50,640 --> 00:08:55,400 Speaker 1: of seeing data outside the normal visual spectrum that we 129 00:08:55,480 --> 00:08:59,079 Speaker 1: can see. For example, it might sound impossible to see 130 00:08:59,120 --> 00:09:02,080 Speaker 1: in the altar for violet range, but it turns out 131 00:09:02,400 --> 00:09:06,360 Speaker 1: your photoreceptors can do that. It's just that the lens 132 00:09:06,440 --> 00:09:10,440 Speaker 1: of your eye blocks out UV light. But then something 133 00:09:10,559 --> 00:09:13,920 Speaker 1: was accidentally discovered in the last couple of decades. A 134 00:09:13,920 --> 00:09:17,199 Speaker 1: lot of people go in for cataract surgery and they 135 00:09:17,200 --> 00:09:22,240 Speaker 1: get their lens exchanged for a synthetic replacement. Your natural 136 00:09:22,320 --> 00:09:26,520 Speaker 1: lens blocks UV, but the replacement lens does not, So 137 00:09:26,600 --> 00:09:31,559 Speaker 1: patients found themselves tapping into ranges of the electromagnetic spectrum 138 00:09:31,760 --> 00:09:34,520 Speaker 1: that they couldn't see before. I wrote about one guy 139 00:09:34,520 --> 00:09:37,080 Speaker 1: in my book Live Wire. His name is Alec, and 140 00:09:37,160 --> 00:09:40,080 Speaker 1: he got a lens replacement for his cataracts, and he 141 00:09:40,160 --> 00:09:42,720 Speaker 1: now describes a lot of things that he looks at 142 00:09:42,760 --> 00:09:46,800 Speaker 1: as having a blue violet glow that other people just 143 00:09:46,840 --> 00:09:49,480 Speaker 1: don't see. He noticed this the day after his cataract 144 00:09:49,520 --> 00:09:53,320 Speaker 1: surgery when he was looking at his son's Colorado Rockies shorts. 145 00:09:53,679 --> 00:09:56,840 Speaker 1: Everyone else saw the shorts as black, but he saw 146 00:09:56,880 --> 00:10:01,080 Speaker 1: them with a blue violet sheen. When he put a 147 00:10:01,240 --> 00:10:03,760 Speaker 1: UV filter over his eye to block out the UV, 148 00:10:04,080 --> 00:10:07,360 Speaker 1: he saw them like everyone else. Here's another example. When 149 00:10:07,360 --> 00:10:09,560 Speaker 1: you look at what's called a black light that's turned on, 150 00:10:09,679 --> 00:10:13,640 Speaker 1: you don't see anything, but Alec sees a bright purple glow. 151 00:10:14,000 --> 00:10:17,720 Speaker 1: So this gives him a new superpower, seeing past the 152 00:10:17,880 --> 00:10:22,560 Speaker 1: normal spectrum of colors. Alec has different kinds of experiences 153 00:10:22,600 --> 00:10:25,920 Speaker 1: than we do when he looks at sunsets, or gas 154 00:10:25,960 --> 00:10:29,559 Speaker 1: stoves or flowers. Now I want to flip the question 155 00:10:29,640 --> 00:10:34,920 Speaker 1: to examine the other side. Could you lose your color vision. Yes, 156 00:10:35,080 --> 00:10:38,360 Speaker 1: it's rare, but it happens, and it's called a chromatopsia. 157 00:10:38,559 --> 00:10:42,679 Speaker 1: People with this condition see the world entirely in shades 158 00:10:42,720 --> 00:10:45,800 Speaker 1: of gray, as if life were filmed through the lens 159 00:10:45,840 --> 00:10:48,240 Speaker 1: of an old black and white movie. It's not just 160 00:10:48,679 --> 00:10:52,800 Speaker 1: muted color or red green confusion. It's the complete absence 161 00:10:52,880 --> 00:10:56,480 Speaker 1: of color perception. Just imagine this, The vibrant world that 162 00:10:56,520 --> 00:10:59,319 Speaker 1: we all take for granted gets rendered by your brain 163 00:10:59,640 --> 00:11:04,000 Speaker 1: in a perpetual gray scale, where even a rainbow is 164 00:11:04,080 --> 00:11:06,880 Speaker 1: just a smooth gradient of light and dark. Now, the 165 00:11:06,920 --> 00:11:09,600 Speaker 1: thing I want to note is that achromatopsia results from 166 00:11:09,679 --> 00:11:13,720 Speaker 1: brain damage, specifically to a region called area V four 167 00:11:13,840 --> 00:11:17,679 Speaker 1: in the visual cortex. Because color vision doesn't happen in 168 00:11:17,720 --> 00:11:21,240 Speaker 1: your eyes alone. While the cone cells in your retina 169 00:11:21,320 --> 00:11:25,640 Speaker 1: detects different wavelengths of light, the experience of color is 170 00:11:25,679 --> 00:11:29,040 Speaker 1: assembled in the brain, and one of the key regions 171 00:11:29,080 --> 00:11:33,920 Speaker 1: responsible for putting those wavelengths together into color perception is 172 00:11:33,960 --> 00:11:36,640 Speaker 1: this area of V four, located in what's known as 173 00:11:36,640 --> 00:11:39,680 Speaker 1: the ventral visual pathway in the brain. The point is, 174 00:11:39,920 --> 00:11:44,480 Speaker 1: if this area is damaged from a stroke, from head trauma, 175 00:11:44,559 --> 00:11:49,240 Speaker 1: from a brain tumor, the person gets this cortical color blindness. 176 00:11:49,320 --> 00:11:52,600 Speaker 1: The eyes are perfectly healthy, but the brain can't interpret 177 00:11:52,960 --> 00:11:57,959 Speaker 1: color signals anymore, so the person experiences the world in grayscale. 178 00:11:58,240 --> 00:12:01,520 Speaker 1: So this once again illustrates the simple but critical point 179 00:12:01,720 --> 00:12:05,120 Speaker 1: that color is a construction of the brain, and you 180 00:12:05,240 --> 00:12:08,160 Speaker 1: have to have all the right pieces and parts running 181 00:12:08,360 --> 00:12:11,440 Speaker 1: or else. You can see just fine, but you can't 182 00:12:11,480 --> 00:12:32,000 Speaker 1: see color. Now. Some people, of course, are born color blind, 183 00:12:32,080 --> 00:12:34,760 Speaker 1: but not because of brain damage, but instead because they 184 00:12:34,760 --> 00:12:38,480 Speaker 1: don't have some of the types of cones in their eye. 185 00:12:38,760 --> 00:12:41,520 Speaker 1: As a reminder, most people are born with three different 186 00:12:41,559 --> 00:12:44,760 Speaker 1: types of cones color photo receptors, but some people are 187 00:12:44,760 --> 00:12:48,320 Speaker 1: born with only two types, or one type or none, 188 00:12:48,600 --> 00:12:54,560 Speaker 1: giving them a diminished or no ability to distinguish between colors. Now, 189 00:12:54,679 --> 00:12:59,839 Speaker 1: the military excludes colorblind soldiers from certain jobs, but they 190 00:12:59,840 --> 00:13:03,160 Speaker 1: have come to realize that colorblind people do have a 191 00:13:03,280 --> 00:13:09,040 Speaker 1: secret superpower. They can spot enemy camouflage better than people 192 00:13:09,080 --> 00:13:14,120 Speaker 1: with normal color vision. Why because they're better at distinguishing 193 00:13:14,200 --> 00:13:17,760 Speaker 1: between shades of gray. This is because they have the 194 00:13:17,800 --> 00:13:20,439 Speaker 1: same amount of visual cortex at the back of their brain, 195 00:13:20,840 --> 00:13:24,360 Speaker 1: but fewer color dimensions to worry about. So they're using 196 00:13:24,400 --> 00:13:28,280 Speaker 1: the same cortical territory, but for a simpler task, just 197 00:13:28,400 --> 00:13:31,720 Speaker 1: gray scale instead of color, and this gives them improved 198 00:13:31,800 --> 00:13:37,520 Speaker 1: performance in distinguishing very subtle differences in brightness. So although 199 00:13:37,600 --> 00:13:39,760 Speaker 1: it would be a real bummer to be colorblind, there 200 00:13:39,800 --> 00:13:43,680 Speaker 1: are some advantages as well. So now let's return to color. 201 00:13:43,800 --> 00:13:46,280 Speaker 1: Everything we've talked about so far as a reminder that 202 00:13:46,400 --> 00:13:50,720 Speaker 1: color is not just about the electromagnetic radiation hitting the eye, 203 00:13:51,080 --> 00:13:54,520 Speaker 1: but about what happens in the brain. And one very 204 00:13:54,520 --> 00:13:58,640 Speaker 1: good example of that is something I've talked about before, synesthesia. 205 00:13:59,120 --> 00:14:03,240 Speaker 1: This is a brain phenomenon in which color blurs with 206 00:14:03,400 --> 00:14:08,160 Speaker 1: different concept a typical citisteit will perceive letters or numbers 207 00:14:08,080 --> 00:14:12,400 Speaker 1: as having fixed colors, like a is always red, or 208 00:14:12,800 --> 00:14:16,319 Speaker 1: the number seven is ce foam green, and it can 209 00:14:16,360 --> 00:14:20,840 Speaker 1: commonly be with weekdays or months like Wednesday is indigo 210 00:14:20,880 --> 00:14:24,720 Speaker 1: blue or August is yellow. Now it's not a hallucination, 211 00:14:25,520 --> 00:14:28,120 Speaker 1: but to the person, it's just self evidently true that 212 00:14:28,120 --> 00:14:31,960 Speaker 1: that's what that letter or number or weekday or month is. 213 00:14:32,400 --> 00:14:35,240 Speaker 1: Of course it's purple or yellow or green. So I've 214 00:14:35,280 --> 00:14:37,920 Speaker 1: studied synesthesia in my lab for many years because it's 215 00:14:37,960 --> 00:14:42,560 Speaker 1: such a good inroad into conscious experience and also the 216 00:14:42,600 --> 00:14:46,800 Speaker 1: differences between one person's experience and another's, and the difference 217 00:14:46,880 --> 00:14:51,440 Speaker 1: is between people's experiences on the inside when they're perceiving 218 00:14:51,480 --> 00:14:54,560 Speaker 1: the world. If you're interested in synesthesia, please listen to 219 00:14:54,720 --> 00:14:57,480 Speaker 1: episode four. But for now, I want to zoom in 220 00:14:57,520 --> 00:15:01,960 Speaker 1: on the issue of colored weekdays, which is a common form. 221 00:15:02,280 --> 00:15:04,640 Speaker 1: The thing I want to emphasize is that the color 222 00:15:04,680 --> 00:15:08,680 Speaker 1: palette ends up being different for each cynisthees. So one 223 00:15:08,760 --> 00:15:13,000 Speaker 1: person might say, oh, Monday is clearly green and Tuesday 224 00:15:13,200 --> 00:15:17,160 Speaker 1: is purple, and Wednesday is yellow, and a different cinisthee 225 00:15:17,440 --> 00:15:21,440 Speaker 1: has a different color palette. Now, I've studied literally thousands 226 00:15:21,480 --> 00:15:24,800 Speaker 1: of such cynthtes, but here's something I just learned that 227 00:15:25,000 --> 00:15:28,920 Speaker 1: really surprised me. I learned that in Thailand there's an 228 00:15:29,000 --> 00:15:32,440 Speaker 1: ancient tradition in which each day of the week has 229 00:15:32,480 --> 00:15:38,280 Speaker 1: a corresponding color, rooted in Hindu based astrology. So Monday 230 00:15:38,480 --> 00:15:43,080 Speaker 1: is yellow, Tuesday is pink, Wednesday is green, and so on. 231 00:15:43,520 --> 00:15:48,120 Speaker 1: Apparently these colors are tied to planetary deities like Mars, 232 00:15:48,120 --> 00:15:53,360 Speaker 1: for Tuesday is associated with pink, Mercury, for Wednesday is green, 233 00:15:53,800 --> 00:15:57,320 Speaker 1: and so on, and traditionally it was believed to bring 234 00:15:57,520 --> 00:16:00,640 Speaker 1: luck if you wore that color or use color on 235 00:16:00,760 --> 00:16:03,680 Speaker 1: the corresponding day. This apparently used to be very common 236 00:16:03,680 --> 00:16:06,880 Speaker 1: in Thailand to wear the right color every single day. 237 00:16:06,920 --> 00:16:09,280 Speaker 1: Today it's a little less common. Now. You can probably 238 00:16:09,280 --> 00:16:11,440 Speaker 1: guess what I'm wondering about, which is where did this 239 00:16:11,600 --> 00:16:15,440 Speaker 1: colored weekday idea come from Well, if you consult any 240 00:16:15,560 --> 00:16:17,720 Speaker 1: Taie book on this, they'll say it comes from the 241 00:16:18,080 --> 00:16:22,600 Speaker 1: colors of their deities. But of course gods don't really exist, 242 00:16:22,680 --> 00:16:26,239 Speaker 1: and if they did, it's not obvious they would have colors, 243 00:16:26,360 --> 00:16:29,280 Speaker 1: or that anyone would have seen those colors. So my 244 00:16:29,360 --> 00:16:32,240 Speaker 1: suspicion is that if we really did get to the 245 00:16:32,280 --> 00:16:36,360 Speaker 1: bottom of this very ancient history, we'd find a very 246 00:16:36,440 --> 00:16:41,400 Speaker 1: influential Cinistheite at bottom, someone who said, well, of course 247 00:16:41,400 --> 00:16:44,440 Speaker 1: Tuesday is pink and Wednesday is green and so on, 248 00:16:44,680 --> 00:16:49,200 Speaker 1: and because of some cult of personality, it stuck, and 249 00:16:49,280 --> 00:16:53,040 Speaker 1: millennia later, kids are still told that this deity is 250 00:16:53,080 --> 00:16:55,040 Speaker 1: this color, so that day is the color and you 251 00:16:55,040 --> 00:16:58,560 Speaker 1: should wear that shirt. And so, like all stories with 252 00:16:58,640 --> 00:17:03,320 Speaker 1: cultural momentum, people accept it. Why because everyone else accepts 253 00:17:03,360 --> 00:17:05,879 Speaker 1: it and for thousands of years, So there must be 254 00:17:05,920 --> 00:17:09,400 Speaker 1: something to it. But that's something I suggest is a 255 00:17:09,560 --> 00:17:16,639 Speaker 1: single influential Cynistheide whose quirky neural network determined what everyone 256 00:17:16,760 --> 00:17:20,359 Speaker 1: wore for hundreds of generations. So if you ever think 257 00:17:20,480 --> 00:17:24,880 Speaker 1: neuroscience doesn't affect culture, take that. And on that topic 258 00:17:24,960 --> 00:17:27,440 Speaker 1: of the intersection between neuroscience and culture, I want to 259 00:17:27,520 --> 00:17:30,919 Speaker 1: zoom the camera out to see what happens when lots 260 00:17:30,920 --> 00:17:34,800 Speaker 1: of humans start talking together about color. So we're going 261 00:17:34,880 --> 00:17:39,240 Speaker 1: to turn now to language. For most listeners of this podcast, 262 00:17:39,320 --> 00:17:44,200 Speaker 1: we look at a rainbow and divide it into red, orange, yellow, green, blue, indigo, violet. 263 00:17:44,480 --> 00:17:47,680 Speaker 1: But not every culture divides the spectrum the same way 264 00:17:47,880 --> 00:17:51,720 Speaker 1: or sees the same number of colors. In some languages, 265 00:17:51,800 --> 00:17:56,080 Speaker 1: there is no distinct word for blue. In other languages, 266 00:17:56,200 --> 00:17:59,359 Speaker 1: green and blue are considered shades of the same color. 267 00:17:59,560 --> 00:18:02,760 Speaker 1: As an example of the kinds of differences here, the 268 00:18:02,960 --> 00:18:07,680 Speaker 1: Himba people of Namibia group colors differently from English speakers. 269 00:18:07,720 --> 00:18:11,000 Speaker 1: They have multiple words for what we call green and 270 00:18:11,240 --> 00:18:15,080 Speaker 1: none for what we call blue. Even ancient texts reveal 271 00:18:15,240 --> 00:18:20,439 Speaker 1: this difference in color vocabularies, So in Homer's Odyssey, the 272 00:18:20,520 --> 00:18:23,480 Speaker 1: sea is never described as blue, but it's described as 273 00:18:23,680 --> 00:18:28,080 Speaker 1: wine dark. Scholars have long puzzled over this poetic phrase. 274 00:18:28,480 --> 00:18:30,720 Speaker 1: Was it a metaphor or was it that the ancient 275 00:18:30,800 --> 00:18:35,119 Speaker 1: Greeks didn't categorize blue the way that we do. Blue 276 00:18:35,160 --> 00:18:38,879 Speaker 1: appears almost nowhere in ancient Greek language, and where it 277 00:18:38,960 --> 00:18:43,280 Speaker 1: does is often ambiguous. Why while in ancient Greece there 278 00:18:43,280 --> 00:18:46,840 Speaker 1: were few blue dyes or paints, and by the way, 279 00:18:46,880 --> 00:18:50,679 Speaker 1: blue animals are extraordinarily rare in nature. So while the 280 00:18:50,880 --> 00:18:55,119 Speaker 1: Egyptians used a synthetic pigment, which we call Egyptian blue, 281 00:18:55,480 --> 00:18:59,000 Speaker 1: the Greeks didn't use or produce blue. So it meant 282 00:18:59,040 --> 00:19:02,280 Speaker 1: that blue was less present in their daily life, or 283 00:19:02,320 --> 00:19:04,840 Speaker 1: in their clothing or in their art, and the thought 284 00:19:04,920 --> 00:19:08,520 Speaker 1: goes that it was therefore less common in the language, 285 00:19:08,600 --> 00:19:10,919 Speaker 1: in the same way that cultures on the equator have 286 00:19:11,119 --> 00:19:16,000 Speaker 1: fewer words for distinguishing types of snow than do northern cultures. 287 00:19:16,359 --> 00:19:19,480 Speaker 1: Now zooming out a moment, there were two researchers, Berlin 288 00:19:19,640 --> 00:19:23,560 Speaker 1: and k who proposed that even though language might have 289 00:19:23,720 --> 00:19:27,560 Speaker 1: different color terms, they all follow a predictable order in 290 00:19:27,600 --> 00:19:30,680 Speaker 1: the development of these terms. In other words, the first 291 00:19:30,680 --> 00:19:34,160 Speaker 1: two terms to appear historically in any language are always 292 00:19:34,359 --> 00:19:38,560 Speaker 1: black and white or dark and light. Then comes red. 293 00:19:39,359 --> 00:19:42,399 Speaker 1: Then when cultures get more culture as they introduce green 294 00:19:42,600 --> 00:19:45,800 Speaker 1: or yellow. Only later do you get things like blue 295 00:19:46,160 --> 00:19:50,080 Speaker 1: and brown and more nuanced shades like pink or orange. 296 00:19:50,640 --> 00:19:55,199 Speaker 1: The hypothesis is that this progression matches the salience of 297 00:19:55,280 --> 00:19:58,840 Speaker 1: colors in the environment. The contrast of light and dark 298 00:19:59,160 --> 00:20:02,919 Speaker 1: is really important, the presence of blood, the ripeness of fruit, 299 00:20:03,320 --> 00:20:06,600 Speaker 1: the necessity of distinguishing between plants. So it's only when 300 00:20:06,640 --> 00:20:10,679 Speaker 1: society has become more complex and encounter more dyes and 301 00:20:10,840 --> 00:20:16,000 Speaker 1: materials and artistic traditions then you get new color terms emerging. 302 00:20:16,280 --> 00:20:19,680 Speaker 1: So different languages have different color terms, and one idea 303 00:20:19,760 --> 00:20:23,560 Speaker 1: that has emerged is called linguistic relativity, which is this 304 00:20:23,680 --> 00:20:27,560 Speaker 1: notion that the language that you speak shapes how you 305 00:20:27,680 --> 00:20:31,119 Speaker 1: perceive the world. The idea is that although all people 306 00:20:31,160 --> 00:20:35,679 Speaker 1: can see blue, if your language doesn't label it distinctly, 307 00:20:36,080 --> 00:20:38,399 Speaker 1: you might not really pay attention to it as a 308 00:20:38,440 --> 00:20:42,480 Speaker 1: separate category. And this is indeed what a lot of 309 00:20:42,720 --> 00:20:46,680 Speaker 1: cognitive science studies have found. Your language shapes at least 310 00:20:46,720 --> 00:20:50,920 Speaker 1: a little bit your color distinctions. For example, the Russian 311 00:20:51,000 --> 00:20:54,879 Speaker 1: language has distinct words for light blue and dark blue, 312 00:20:55,160 --> 00:20:59,159 Speaker 1: and when Russians are tested on their ability to distinguish 313 00:20:59,400 --> 00:21:03,320 Speaker 1: shades of blue, they're faster at spotting the difference between 314 00:21:03,440 --> 00:21:06,880 Speaker 1: light and dark blues than English speakers, who use one 315 00:21:06,880 --> 00:21:11,159 Speaker 1: word for both blue. In other words, Russian speaking brains 316 00:21:11,640 --> 00:21:16,080 Speaker 1: process the difference more quickly, suggesting that having a word 317 00:21:16,200 --> 00:21:19,640 Speaker 1: for something helps you see it. If your language has 318 00:21:19,640 --> 00:21:23,440 Speaker 1: more precise blue terms, like Russian, you can distinguish shades 319 00:21:23,480 --> 00:21:27,080 Speaker 1: faster than languages that don't, like English, and you can 320 00:21:27,119 --> 00:21:30,240 Speaker 1: see the same story in babies. Infants can see color 321 00:21:30,320 --> 00:21:33,560 Speaker 1: long before they learn to speak, but once they acquire 322 00:21:33,640 --> 00:21:39,600 Speaker 1: the words for specific colors, their ability to distinguish them improves. 323 00:21:40,440 --> 00:21:46,160 Speaker 1: Language tunes the brain to attend to specific aspects of 324 00:21:46,200 --> 00:21:49,399 Speaker 1: the scene. So if the Greeks didn't have a strong 325 00:21:49,440 --> 00:21:52,520 Speaker 1: word for blue, they might have grouped it with other 326 00:21:52,600 --> 00:21:56,200 Speaker 1: colors like green or gray and not really noticed it 327 00:21:56,240 --> 00:21:59,919 Speaker 1: as blue. The Greeks didn't lack the ability to see blue, 328 00:22:00,480 --> 00:22:03,280 Speaker 1: but in their culture they didn't isolate it with language, 329 00:22:03,760 --> 00:22:07,480 Speaker 1: likely because blue was rare in their environment and their 330 00:22:07,560 --> 00:22:11,719 Speaker 1: language hadn't evolved to distinguish it clearly. So when Homer 331 00:22:11,840 --> 00:22:15,560 Speaker 1: describes the sea as wine dark, it's not because he 332 00:22:15,640 --> 00:22:19,199 Speaker 1: was colorblind. It's because the way his culture saw and 333 00:22:19,320 --> 00:22:22,480 Speaker 1: named colors was a little different from ours. And by 334 00:22:22,520 --> 00:22:24,560 Speaker 1: the way this issue about the Greeks and blue, the 335 00:22:24,560 --> 00:22:28,359 Speaker 1: same is true of many ancient languages, including Hebrew and 336 00:22:28,480 --> 00:22:31,800 Speaker 1: Chinese and Japanese, and in modern studies we can look 337 00:22:31,840 --> 00:22:34,680 Speaker 1: at the Himba people who as I mentioned have multiple 338 00:22:34,680 --> 00:22:39,000 Speaker 1: words for green and none for blue. In experiments, they 339 00:22:39,000 --> 00:22:43,639 Speaker 1: can easily distinguish green shades that we Westerners struggle to 340 00:22:43,680 --> 00:22:46,640 Speaker 1: tell apart, but they find it difficult to pick out 341 00:22:46,680 --> 00:22:50,480 Speaker 1: a blue square from a field of green. Now we've 342 00:22:50,520 --> 00:22:54,639 Speaker 1: been talking about biology and language, but what's fascinating is 343 00:22:54,680 --> 00:22:59,439 Speaker 1: how this private phenomenon of color takes on cultural meaning. 344 00:22:59,800 --> 00:23:03,520 Speaker 1: A million examples of this. I'll just do a quick whistlestop, TORP. 345 00:23:03,600 --> 00:23:06,000 Speaker 1: So just look at the way we organize our world 346 00:23:06,119 --> 00:23:08,600 Speaker 1: through color. We have red states and blue states. We 347 00:23:08,680 --> 00:23:12,159 Speaker 1: have green energy, we have black markets, we have white lies. 348 00:23:12,680 --> 00:23:18,320 Speaker 1: Color becomes shorthand for complex social and political ideas. Even 349 00:23:18,359 --> 00:23:22,480 Speaker 1: our moral frameworks become color coded. You've got the white 350 00:23:22,480 --> 00:23:24,760 Speaker 1: hat and the black hat, and the old Westerns. You've 351 00:23:24,760 --> 00:23:27,160 Speaker 1: got the white dove of peace, you have the red 352 00:23:27,280 --> 00:23:30,880 Speaker 1: devil of temptation. And colors very commonly come to signal 353 00:23:31,000 --> 00:23:35,560 Speaker 1: identity and allegiance. You have teams and uniforms that define 354 00:23:35,720 --> 00:23:40,520 Speaker 1: us versus them by color. Movements adopt symbolic palettes. So 355 00:23:40,560 --> 00:23:44,600 Speaker 1: the Suffragettes wore white and green and violet. AIDS awareness 356 00:23:44,680 --> 00:23:49,560 Speaker 1: uses red, environmental causes green. You see rainbow flags and 357 00:23:49,680 --> 00:23:54,159 Speaker 1: pride parades. You see orange worn by anti gun violence advocates. 358 00:23:54,440 --> 00:23:57,119 Speaker 1: So in this way, when we look around, we see 359 00:23:57,160 --> 00:24:01,640 Speaker 1: that color comes to serve as a quick symbol flag. Now, 360 00:24:01,680 --> 00:24:06,240 Speaker 1: not surprisingly, there's nothing fundamental about these associations and therefore 361 00:24:06,600 --> 00:24:10,960 Speaker 1: they aren't static. So in the eighteen hundreds, pink was 362 00:24:11,000 --> 00:24:16,080 Speaker 1: considered a strong masculine color related to red. Blue was 363 00:24:16,119 --> 00:24:20,199 Speaker 1: seen as delicate and feminine. These meanings flipped in the 364 00:24:20,240 --> 00:24:22,879 Speaker 1: twentieth century, and it had to do with shifts in 365 00:24:22,960 --> 00:24:28,360 Speaker 1: fashion and marketing and cultural signaling. Color, like language, evolves 366 00:24:28,560 --> 00:24:32,040 Speaker 1: and political colors vary. So you've got red for the 367 00:24:32,200 --> 00:24:35,679 Speaker 1: left in Europe, blue for conservatives in the UK, and 368 00:24:35,760 --> 00:24:38,440 Speaker 1: it's reversed in the United States. What I recently read 369 00:24:38,480 --> 00:24:40,919 Speaker 1: is that the colors in the United States blue for 370 00:24:41,040 --> 00:24:45,000 Speaker 1: liberals and red for conservatives. This got nailed down just 371 00:24:45,119 --> 00:24:48,520 Speaker 1: around the year two thousand, when the major television networks 372 00:24:48,560 --> 00:24:52,600 Speaker 1: started using this as a visual shorthand for liberal and conservative, 373 00:24:52,880 --> 00:24:56,800 Speaker 1: and that's how it got crystallized into public consciousness. I 374 00:24:56,800 --> 00:24:59,000 Speaker 1: don't really know the history of this, but I suspect 375 00:24:59,359 --> 00:25:02,359 Speaker 1: then in the day decades of black and white newspapers, 376 00:25:02,720 --> 00:25:05,560 Speaker 1: it was easier to use a donkey and an elephant 377 00:25:05,640 --> 00:25:09,320 Speaker 1: to distinguish the parties. And only when color television became 378 00:25:09,440 --> 00:25:14,520 Speaker 1: ubiquitous did it make sense to introduce a quick color flag. Okay, So, 379 00:25:14,560 --> 00:25:18,320 Speaker 1: now coming back to cultural messages, what is conveyed by 380 00:25:18,359 --> 00:25:23,400 Speaker 1: a color depends on your local context. In Western traditions, 381 00:25:23,760 --> 00:25:27,679 Speaker 1: white is associated with purity and innocence and weddings, but 382 00:25:27,760 --> 00:25:31,880 Speaker 1: in many Eastern cultures, white symbolizes death and is worn 383 00:25:31,960 --> 00:25:36,119 Speaker 1: by mourners. In South Africa, red can be a color 384 00:25:36,160 --> 00:25:40,760 Speaker 1: of mourning. In Brazil, purple is reserved for funerals. I'll 385 00:25:40,760 --> 00:25:44,040 Speaker 1: give you another example. Red, which in the West can 386 00:25:44,080 --> 00:25:48,840 Speaker 1: symbolize danger or passion, is associated in China with celebration 387 00:25:49,000 --> 00:25:52,400 Speaker 1: and joy and luck. A bride in India might wear 388 00:25:52,480 --> 00:25:56,080 Speaker 1: a bright red sorry, while a Western bride walks down 389 00:25:56,080 --> 00:25:58,600 Speaker 1: the aisle in white. So the point here is that 390 00:25:58,840 --> 00:26:03,240 Speaker 1: cultural colors symbols are learned. They're not innate. They are 391 00:26:03,280 --> 00:26:24,680 Speaker 1: built from shared stories and traditions and rituals. Now, despite 392 00:26:24,720 --> 00:26:28,520 Speaker 1: this variation, as far as what color means what sometimes, 393 00:26:28,840 --> 00:26:31,280 Speaker 1: there is a logic to it. Now, one thing I've 394 00:26:31,280 --> 00:26:36,240 Speaker 1: always found fascinating is that purple is always associated with royalty. 395 00:26:36,640 --> 00:26:40,400 Speaker 1: Why purple, why not orange or yellow or something else. Well, 396 00:26:40,400 --> 00:26:43,600 Speaker 1: it turns out that started in ancient Rome with a 397 00:26:43,800 --> 00:26:47,240 Speaker 1: die called Tyrian purple. This was a deep hue and 398 00:26:47,280 --> 00:26:50,000 Speaker 1: it was unlike any other dye that was available at 399 00:26:50,040 --> 00:26:54,120 Speaker 1: the time, and the color became irreversibly associated in their 400 00:26:54,160 --> 00:26:59,200 Speaker 1: society with nobility and wealth and the divine aura of emperors. 401 00:26:59,400 --> 00:27:03,040 Speaker 1: But what was so special about it? While Tyrian purple 402 00:27:03,640 --> 00:27:07,360 Speaker 1: was made from the mucus of a specific sea snail, 403 00:27:07,720 --> 00:27:11,879 Speaker 1: so producing just one gram of dye required thousands of 404 00:27:11,920 --> 00:27:15,879 Speaker 1: snails and days of labor. In other words, the die 405 00:27:16,320 --> 00:27:21,800 Speaker 1: was extremely labor intensive and therefore very expensive. Only the 406 00:27:21,840 --> 00:27:25,719 Speaker 1: wealthiest could afford it, and so that's how a particular 407 00:27:25,800 --> 00:27:30,159 Speaker 1: color came to represent something. What's interesting is that it 408 00:27:30,280 --> 00:27:33,520 Speaker 1: started off as an economic issue, but by the Roman 409 00:27:33,560 --> 00:27:39,320 Speaker 1: imperial era, the association between purple and power was codified 410 00:27:39,440 --> 00:27:42,800 Speaker 1: in the law. So you weren't allowed to wear garments 411 00:27:42,960 --> 00:27:46,760 Speaker 1: dyed in Tyrian purple unless you were an emperor or 412 00:27:46,800 --> 00:27:49,960 Speaker 1: a high ranking official. Apparently you could be sighted with 413 00:27:50,160 --> 00:27:54,240 Speaker 1: treason if you did this. So purple started out as expensive, 414 00:27:54,520 --> 00:27:58,680 Speaker 1: but it eventually became politically exclusive and By the way, 415 00:27:58,680 --> 00:28:02,080 Speaker 1: this wasn't just Rome. In various societies you find these 416 00:28:02,240 --> 00:28:06,359 Speaker 1: laws called sumptuary laws, which are like dress codes backed 417 00:28:06,359 --> 00:28:10,200 Speaker 1: by law, and these are there to restrict which people 418 00:28:10,320 --> 00:28:13,240 Speaker 1: can wear which colors. For example, you find the same 419 00:28:13,320 --> 00:28:17,960 Speaker 1: kind of sumptuary law in Elizabethan, England, where only royalty 420 00:28:18,080 --> 00:28:22,400 Speaker 1: and nobility were allowed to wear certain dies. The idea 421 00:28:22,440 --> 00:28:25,720 Speaker 1: with these laws is that they're designed to visibly maintain 422 00:28:26,000 --> 00:28:30,760 Speaker 1: the social order. So again, colors become a shorthand label 423 00:28:31,200 --> 00:28:34,760 Speaker 1: for larger concepts. Okay, so we've talked about this terrific 424 00:28:34,880 --> 00:28:39,320 Speaker 1: history of colors where certain colors came to have particular meaning. 425 00:28:39,840 --> 00:28:44,360 Speaker 1: But then what happened was the invention of synthetic dyes 426 00:28:44,440 --> 00:28:48,000 Speaker 1: in the nineteenth century, and suddenly you had this explosion 427 00:28:48,080 --> 00:28:52,480 Speaker 1: of vibrant hues that became accessible to the masses. The 428 00:28:52,560 --> 00:28:56,480 Speaker 1: first synthetic dye was mauve, and that was discovered accidentally 429 00:28:56,480 --> 00:29:00,760 Speaker 1: in eighteen fifty six, and that sparked a fashion because 430 00:29:00,800 --> 00:29:05,920 Speaker 1: what followed was an explosion of new hues, artificial magentas 431 00:29:05,960 --> 00:29:10,080 Speaker 1: and bright greens and vivid blues and optimistic yellow and 432 00:29:10,120 --> 00:29:15,800 Speaker 1: eventually drunk tank pink and ultramarine and atomic tangerine and 433 00:29:16,040 --> 00:29:19,880 Speaker 1: Nato green and millennial pink and safety orange and on 434 00:29:19,960 --> 00:29:23,240 Speaker 1: and on. So the world in a very short period 435 00:29:23,280 --> 00:29:27,800 Speaker 1: of time became much more colorful. So that's the recent 436 00:29:28,000 --> 00:29:31,000 Speaker 1: history of color. But I'm also interested in the flip 437 00:29:31,040 --> 00:29:34,640 Speaker 1: side question, which is what is the future of color, 438 00:29:35,080 --> 00:29:38,560 Speaker 1: because we're beginning to enter an era where color doesn't 439 00:29:38,600 --> 00:29:41,200 Speaker 1: have to be limited to what the ie evolved to 440 00:29:41,280 --> 00:29:43,880 Speaker 1: see or the dyes that we're able to make. First 441 00:29:43,880 --> 00:29:46,959 Speaker 1: of all, we're well beyond dies now because our modern 442 00:29:46,960 --> 00:29:50,880 Speaker 1: technology has changed how we see color. We have digital 443 00:29:50,920 --> 00:29:54,960 Speaker 1: screens that use RGB red, green, blue, and they mix 444 00:29:55,160 --> 00:29:59,720 Speaker 1: light instead of pigment, and any typical screen now displays 445 00:29:59,720 --> 00:30:04,080 Speaker 1: over sixteen million different colors. But the future of color 446 00:30:04,320 --> 00:30:06,320 Speaker 1: is going to go way further than that. As a 447 00:30:06,320 --> 00:30:08,960 Speaker 1: simple example, we've talked about how color can be used 448 00:30:09,120 --> 00:30:13,280 Speaker 1: to label information, so we can use augmented reality glasses 449 00:30:13,360 --> 00:30:16,640 Speaker 1: to map colors on the fly. Imagine that you are 450 00:30:16,960 --> 00:30:19,720 Speaker 1: in a factory where some machines are hot and some 451 00:30:19,840 --> 00:30:23,000 Speaker 1: are cold, and you just map the temperature data onto 452 00:30:23,400 --> 00:30:26,160 Speaker 1: red or blue so that you can see the temperature 453 00:30:26,200 --> 00:30:28,240 Speaker 1: at a distance. And of course it doesn't have to 454 00:30:28,280 --> 00:30:31,320 Speaker 1: be temperature. It could be anything like how full the 455 00:30:31,400 --> 00:30:34,360 Speaker 1: tanks are, or how many cycles per second are running 456 00:30:34,360 --> 00:30:38,280 Speaker 1: on the chips, or whatever information you need to carry. 457 00:30:38,440 --> 00:30:41,440 Speaker 1: You can encode that in color. But it gets better 458 00:30:41,480 --> 00:30:46,320 Speaker 1: than that, because new technologies are actually expanding the colors 459 00:30:46,360 --> 00:30:50,840 Speaker 1: that you can see. You can zap particular photoreceptors and 460 00:30:50,920 --> 00:30:55,640 Speaker 1: not others to see more saturated colors than you've ever 461 00:30:55,680 --> 00:30:59,120 Speaker 1: seen before. So at Berkeley, my colleagues have pulled off 462 00:30:59,120 --> 00:31:02,720 Speaker 1: a new project where a bypass your eyes normal machinery 463 00:31:03,080 --> 00:31:07,040 Speaker 1: and paint directly on your retina with light. And what 464 00:31:07,080 --> 00:31:10,160 Speaker 1: they can create is a brand new color, a literally 465 00:31:10,200 --> 00:31:15,560 Speaker 1: never before seen Hugh, a supersaturated blue green that the 466 00:31:15,600 --> 00:31:21,280 Speaker 1: research team calls ololo. What does olo look like? So 467 00:31:21,400 --> 00:31:25,080 Speaker 1: picture the most saturated peel that you can imagine, then 468 00:31:25,440 --> 00:31:29,240 Speaker 1: crank it up past anything nature offers. The green of 469 00:31:29,320 --> 00:31:33,000 Speaker 1: a laser pointer feels dull in comparison. Here's how it works. 470 00:31:33,280 --> 00:31:38,080 Speaker 1: Using very tiny doses of laser light, they individually target 471 00:31:38,160 --> 00:31:42,040 Speaker 1: photoreceptors in your eye. They don't just hit one photoreceptor, 472 00:31:42,040 --> 00:31:46,160 Speaker 1: but an entire constellation of about one thousand cones. It's 473 00:31:46,200 --> 00:31:48,840 Speaker 1: like they're painting on a tiny movie screen the size 474 00:31:48,840 --> 00:31:52,600 Speaker 1: of your fingernail. They're painting with light directly on your retina. 475 00:31:52,840 --> 00:31:56,160 Speaker 1: The key is that normally, each one of your cone 476 00:31:56,160 --> 00:31:59,719 Speaker 1: cells responds to different wavelengths short, medium, or long. But 477 00:31:59,760 --> 00:32:02,520 Speaker 1: there's so much overlap in the green and the red 478 00:32:02,560 --> 00:32:06,880 Speaker 1: cones that has been impossible to isolate just the green 479 00:32:06,960 --> 00:32:10,720 Speaker 1: cones the medium wavelength cones. But using this technique, that's 480 00:32:10,720 --> 00:32:13,840 Speaker 1: what they can do. So when only the medium cones 481 00:32:13,920 --> 00:32:17,600 Speaker 1: are stimulated, the result is Olo, a color that doesn't 482 00:32:17,680 --> 00:32:21,200 Speaker 1: exist anywhere in the natural world. Now, if the laser 483 00:32:21,360 --> 00:32:25,680 Speaker 1: jitters accidentally so that it activates nearby cones, the illusion 484 00:32:25,720 --> 00:32:28,600 Speaker 1: collapses in your back to just plain green, and that 485 00:32:28,760 --> 00:32:32,640 Speaker 1: shows how fragile this new color really is. So this 486 00:32:32,680 --> 00:32:37,160 Speaker 1: is how we can unlock entirely new sensory experiences. Your 487 00:32:37,240 --> 00:32:41,000 Speaker 1: brain is seeing something it never evolved to see, and 488 00:32:41,040 --> 00:32:43,840 Speaker 1: that brings us back to a deep question in neuroscience. 489 00:32:43,920 --> 00:32:47,400 Speaker 1: What happens when you feed the brain new information it's 490 00:32:47,440 --> 00:32:50,360 Speaker 1: never had before, And we see that the brain just 491 00:32:50,480 --> 00:32:53,360 Speaker 1: makes up a new color Olo, which is not born 492 00:32:53,440 --> 00:32:56,640 Speaker 1: of the saun or of nature, but of precise cellular 493 00:32:56,760 --> 00:33:00,160 Speaker 1: targeting in the lab. And so the possibility is there 494 00:33:00,600 --> 00:33:03,800 Speaker 1: that maybe we're just at the beginning of what human 495 00:33:03,920 --> 00:33:08,520 Speaker 1: perception is capable of. What amazes me is that we 496 00:33:08,560 --> 00:33:11,960 Speaker 1: can't imagine new colors, but once we've seen them, then 497 00:33:12,000 --> 00:33:14,720 Speaker 1: it's part of what we can imagine. And this tells 498 00:33:14,760 --> 00:33:18,800 Speaker 1: us that there's always more beyond the fence lines of 499 00:33:18,840 --> 00:33:22,239 Speaker 1: our internal models, which is what my next book is on, 500 00:33:22,280 --> 00:33:24,920 Speaker 1: which will hopefully come out next year. Okay, now I 501 00:33:24,960 --> 00:33:28,120 Speaker 1: want to get back to how science is going to 502 00:33:28,160 --> 00:33:32,840 Speaker 1: expand our perception. I think it's inevitable that genetic tools 503 00:33:32,880 --> 00:33:36,240 Speaker 1: are going to make it possible someday to modify our 504 00:33:36,440 --> 00:33:40,040 Speaker 1: eyes to detect new parts of the spectrum. So, for example, 505 00:33:40,440 --> 00:33:45,520 Speaker 1: will someday genetically give humans new flavors of photoreceptor cells? 506 00:33:46,000 --> 00:33:48,800 Speaker 1: Could you add a fourth type of cone to the retina? 507 00:33:49,160 --> 00:33:52,400 Speaker 1: I told you last week about tetrachromacy, in which a 508 00:33:52,480 --> 00:33:56,400 Speaker 1: tiny fraction of women see hundreds of millions of colors 509 00:33:56,480 --> 00:33:58,800 Speaker 1: rather than let's say a million, which is what most 510 00:33:58,800 --> 00:34:01,120 Speaker 1: of us can see. And this is because they have 511 00:34:01,160 --> 00:34:05,240 Speaker 1: a genetic mutation that gives them a fourth cone type. 512 00:34:05,760 --> 00:34:10,880 Speaker 1: So you could genetically engineer tetrachromacy like this. But you 513 00:34:10,920 --> 00:34:14,719 Speaker 1: could also engineer a fourth cone type to see beyond 514 00:34:14,880 --> 00:34:20,279 Speaker 1: the current limits of visible light. Imagine your great grandkids 515 00:34:20,320 --> 00:34:24,520 Speaker 1: being able to see magnetic fields like soft glows of color, 516 00:34:24,840 --> 00:34:27,279 Speaker 1: or to see other things that are totally invisible to you, 517 00:34:27,400 --> 00:34:31,520 Speaker 1: like infrared or ultraviolet, like snakes or bees do This 518 00:34:31,560 --> 00:34:34,640 Speaker 1: would just be an extension of the way that our 519 00:34:34,680 --> 00:34:38,719 Speaker 1: brains use colors as a way of tagging information in 520 00:34:38,760 --> 00:34:43,800 Speaker 1: the world. But now we'll be extending our perception beyond 521 00:34:44,080 --> 00:34:50,080 Speaker 1: its biological history. So let's wrap up. Color feels like 522 00:34:50,120 --> 00:34:53,759 Speaker 1: one of the most real and immediate and obvious aspects 523 00:34:53,920 --> 00:34:57,280 Speaker 1: of our experience. We fall in love with somebody's eyes, 524 00:34:57,680 --> 00:35:00,759 Speaker 1: we remember the yellow walls of a child bedroom. We 525 00:35:01,320 --> 00:35:05,240 Speaker 1: mourn in black, we celebrate in white or red or gold. 526 00:35:05,360 --> 00:35:07,720 Speaker 1: But what we've seen in this episode, in the last 527 00:35:07,840 --> 00:35:12,440 Speaker 1: is that color isn't fundamentally a property of the outside world. 528 00:35:12,640 --> 00:35:16,160 Speaker 1: It's a creation of the brain. There's no color in 529 00:35:16,200 --> 00:35:20,760 Speaker 1: a photon, there's just energy, just wavelength, and your retina 530 00:35:21,280 --> 00:35:25,000 Speaker 1: receives that input, and your brain compares and contrasts it 531 00:35:25,000 --> 00:35:29,200 Speaker 1: with other inputs, and out of this massive internal computation, 532 00:35:29,719 --> 00:35:33,960 Speaker 1: you experience something radiant and vivid, and by the way. 533 00:35:34,000 --> 00:35:36,799 Speaker 1: It's quite personal, which is why a blue and black 534 00:35:36,880 --> 00:35:41,040 Speaker 1: dress can divide the Internet. So the next time you 535 00:35:41,120 --> 00:35:45,560 Speaker 1: admire a sunset, or choose a shirt, or linger over 536 00:35:45,600 --> 00:35:52,200 Speaker 1: a painting, remember that you're translating physics into a subjective interpretation. 537 00:35:52,760 --> 00:35:57,200 Speaker 1: Color is a collaboration between the external world and your 538 00:35:57,320 --> 00:36:02,560 Speaker 1: internal model of it. It's where physics color lies with perception. Finally, 539 00:36:02,600 --> 00:36:05,000 Speaker 1: I just want to revisit how crazy I think it 540 00:36:05,080 --> 00:36:09,320 Speaker 1: is that we see colors every day that Julius Caesar 541 00:36:09,880 --> 00:36:14,120 Speaker 1: never did, and not just Caesar, but Shakespeare and Pocahontas 542 00:36:14,120 --> 00:36:19,640 Speaker 1: and Abraham Lincoln everyone. Until the proliferation of synthetic dies 543 00:36:19,719 --> 00:36:23,640 Speaker 1: and eventually digital screens, the world before us just didn't 544 00:36:23,640 --> 00:36:26,760 Speaker 1: see that many colors, colors that we get to see 545 00:36:27,080 --> 00:36:31,200 Speaker 1: every day, and typically don't even consider the size of 546 00:36:31,280 --> 00:36:34,279 Speaker 1: the palette that we get to appreciate. So spend a 547 00:36:34,280 --> 00:36:38,120 Speaker 1: few minutes today just looking around and thinking about the 548 00:36:38,239 --> 00:36:41,040 Speaker 1: millions of hues that you're looking at. Look at the 549 00:36:41,640 --> 00:36:45,680 Speaker 1: fashion around you, the clothing, the car colors, the paints, 550 00:36:46,080 --> 00:36:49,000 Speaker 1: even the annoying stuff like the advertising posters and the 551 00:36:49,080 --> 00:36:53,680 Speaker 1: road signs, even these are quite extraordinary when you look 552 00:36:53,719 --> 00:36:57,120 Speaker 1: at them. Through a new lens of appreciation, and I'm 553 00:36:57,160 --> 00:37:01,640 Speaker 1: really fascinated in thinking about how iotech will reach into 554 00:37:01,840 --> 00:37:06,399 Speaker 1: new color territories that we can't currently imagine. I told 555 00:37:06,400 --> 00:37:09,800 Speaker 1: you about the new color olo made by zapping specific 556 00:37:09,880 --> 00:37:13,640 Speaker 1: photoreceptors and not others in the lab. Just imagine what 557 00:37:13,680 --> 00:37:16,560 Speaker 1: things are going to look like in a century. Our 558 00:37:16,640 --> 00:37:20,520 Speaker 1: descendants might feel as sorry for us and our pitiful 559 00:37:20,560 --> 00:37:30,680 Speaker 1: little spectrum as we feel for our distant ancestors. Go 560 00:37:30,800 --> 00:37:33,759 Speaker 1: to eagleman dot com slash podcast for more information and 561 00:37:33,800 --> 00:37:37,600 Speaker 1: to find further reading. Join the weekly discussions on my substack, 562 00:37:37,680 --> 00:37:40,480 Speaker 1: and check out and subscribe to Inner Cosmos on YouTube 563 00:37:40,640 --> 00:37:45,600 Speaker 1: for videos of each episode and to leave comments Until 564 00:37:45,640 --> 00:37:52,280 Speaker 1: next time. I'm David Eagleman, and this is Inner Cosmos.