May 21, 2012


Our world is saturated in color, from soft hues to violent stains. How does something so intangible pack such a visceral punch? This hour, in the name of science and poetry, Jad and Robert tear the rainbow to pieces.


To what extent is color a physical thing in the physical world, and to what extent is it created in our minds? We start with Sir Isaac Newton, who was so eager to solve this very mystery, he stuck a knife in his eye to pinpoint the answer. Then, we meet a sea creature that sees a rainbow way beyond anything humans can experience, and we track down a woman who we're pretty sure can see thousands (maybe even millions) more colors than the rest of us. And we end with an age-old question, that, it turns out, never even occurred to most humans until very recently: why is the sky blue?

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[sonic ID]


JG: And I assume we’re live on the air now.




JA: We don’t do live.




RK: Have you guys ever talked to each other?


JA: I don’t think so no.




RK: Oh so this so this is Jad Abumrad.


JG: Well hi.


RK: This is Jim Gleick.


JA: Hi how are you?


JG: Fine how are you?




JA: Pretty good pretty good.




JA: Rainbows rainbows. Okay so we’re gonna start today with author


JG: [clears throat]




JA: James Gleick.


JG: As I recall, you wanted to talk about Isaac Newton.

RK: That’s right.


JA: We did call him to talk about Isaac Newton but more specifically, colors.


JG: All right Isaac Newton - he’s 23 years old.


JA: 1665.


JG: And he’s - he’s home for the holidays - no, there’s no holiday. He’s home for the plague.


JA: There was actually a plague. They sent everybody home from school. In any case, he’s in his room - famously




solving all these mysteries of the world. And one of the questions that he thinks about during this break is -


JG: What are colors?




JG: Where do they come from?

RK: Like when I see the color red, is that red - is it inside my head or is it something that exists sort of out there in the world?

JG: Yes the light without or it’s the light within.

JA: Hm.

JG: So he pokes a knife into his eye.

JA: He what??

RK: He -

JA: What do you mean?


JG: Here’s what Newton wrote in




JG: his notebook:


Masc voice: I took a bodekin -




put it betwixt my eye and the bone as near to the backside of my eye as I could.


JA: Ugh.


Masc voice: And pressing my eye with the end of it, there appeared several white and colored circles.


RK: Huh.

JA: Did that lead to him some conclusion about where the spots live?




JA: Whether they’re outside or inside?

JG: No. This didn’t get him very far.


JA: Cause seeing spots when you poke your eye doesn’t tell you much about what color is.


JG: But um -


JA: But what he did next did.




And this one he’s a little more famous for.


RK: He got himself a prism which is just a - a bit of glass shaped like a pyramid.


JG: Wasn’t so easy for him to get his hands on a prism, but he did.


RK: Then he shut his blinds so the room was totally dark. But he poked a little hole




RK: in one of the blinds and then he waited -


JG: And the sun had to be at just the right angle.


RK: And he waited. And when the sun got to just the right spot. A ray of light shot through the room, Newton immediately stuck his prism into




the light and the light - shattered and became -  


JG: A rainbow on the wall.


JA: Or in Newton’s own words.


VF: A colored image of the sun. Now that’s gorgeous isn’t it.

RK: Mm.

VF: A colored image of the sun.


JA: That’s Victoria Finley, she wrote a book about color and she says - the thing to understand about this experiment is at the time, people believed that white light -


VF: Was given by god or given given by - this amazing thing called






JG: The light from the sun was sort of holy.

VF: Yeah!

JG: If there was anything that was pure it was white.




JA: So when the prism did the rainbow thing which people knew prisms did - they just figured -


JG: The colors are in there, in the glass.


JA: In other words that rainbow had nothing to do with the light itself. That was just the prism.


JG: Adding some kind of impurities to the light.

RK: Oh wow I hadn’t thought of the possibility that the prism is muddying the light. It’s polluting -

JG: Yeah that’s -

RK: the light.

JG: Well how do you know that the prism isn’t generating these colors?

RK: Yeah.

JG: So he got a second




prism. And this was the trick.


JA: While the first prism was still making that rainbow




on the wall -


JG: He moved a few feet away and he held up a second prism in the blue area to see what would happen to the blue light.


JA: Would the prism add more colors to the blue light?


JG: Or would it be transformed in some other way? And what he found was - nothing happened, it remains blue.




JA: So he thought hm - if the blue light isn’t getting muddied by the prism, then maybe the




prism wasn’t muddying the white light to begin with. Maybe that rainbow of colors was actually coming from inside the white light!


JG: He inferred that the first prism is dividing light into its constituent parts.


VF: Which means that that white light we see around us is actually constituted of all of these colors.




JA: The colors were in the light, they are the light! He had his answer. Light is a physical thing in the physical world. You can tweak it. Test it. Study it. This was the beginning of everything we know about light today.


JG: Which Newton put us on the road




toward finding.


JA: That ultraviolet rays, x-rays, radio waves, they’re all different energies of light and colors are just energies within that little sliver that we can see. And that has led to our understanding of the greenhouse effect. Knowing what stars are made of. Even the age of our own universe.


RK: But - not everybody was pleased




by this.


VF: Well a little bit later, John Keats, a romantic




poet, was really cross with him in a in a poem because they said he reduced - removed all the poetry of the rainbow.


RK: And the real challenge to Newton’s view of. Color - one that would really stick - oddly enough it did come from a poet - not Keats but a - the poet named [Gerta?].


JL: Yeah he was this German romantic poet.


JA: That is author Jonah Lehrer.


RK: A regular with us who writes about this kind of thing, always wonderfully.


JL: One day he is walking in the park and he spots these yellow crocuses.




JL: And he looks at the yellow




crocuses and admires their petals, it’s - you know it’s early spring and they’re blooming. And then he quickly turns away.


JA: And in an instant - he suddenly sees-  




JL: This dash of violet across his eyes.


RK: He still sees the shape of the flower but now it’s violet. It’s the opposite of yellow. He hadn’t rubbed his eye, he hadn’t




RK: stuck a needle in it and yet there it was.


JL: - seemed just as real.


RK: As real as the yellow crocus.


JL: And yet he knew it wasn’t real, it came from inside his mind. And and it was - you know it’s something you know -




we’ve all hallucinated colors, you can press on your eyeball or close your eyes and you see this riot of fireworks but - for [Gerta?] that simple observation leads him to think that maybe color isn’t simply about the external universe. That maybe our perception of colors began in the world. But maybe it was finished inside the mind.


RK: And today hundreds of years later this is still an open question.


JG: A scientist can say color has an objective reality. But - the colors we see- are tricks of the imagination.




And there is no perfectly objective view of color. I - personally I like to - keep both of those opinions in mind at the same time.


RK: Me too.


JA: Me three. Well lucky for us-




We’re gonna do a whole show on this!


RK: You don’t say!


JA: I’m Jad Abumrad.


RK: I’m Robert Krulwich.


JA: This is Radiolab and today -


RK: It’s all about color.


JA: Yes.


RK: Where is color?




JA: Is it in, is it out?


RK: That’s the question.


JA: Yeah! We’re gonna explore that question through the eyes of the butterfly.


RK: In the killing fields of Cambodia.


JA: With a woman who may see colors the rest of us can only dream of.


RK: And we’ll go back to a time where the sea apparently looked like dark red wine.


JA: Stick us in your ear holes cause we’re about to get colorful.




JA: And by the way - just before we get rolling, just wanna say - we did something kind of




different for us uh while making this hour. We put out this call to a bunch of musicians - solo artists, bands, to send us their favorite color songs. Their own interpretations of their favorite color song.




JA: We got an amazing response. So throughout this hour, you’re gonna hear color songs of various kinds uh - woven into some of the pieces between the pieces -


RK: Those songs by the way we have plans for.


JA: Yeah.




Big plans. You can go to our website to get a full list of the songs.


RK: And thank you by the way, everybody who sent us those songs.




JA: Absolutely. Okay so uh should we go?


RK: Yes. Let’s uh - so to to get things going um -


JA: Hi. Here - here he is.


RK: Not long after we talked to Jim Glick about Sir Isaac Newton - we talked to a neuroscientist by the name of Mark Changizi.


JA: I’m gonna chew grapes if that’s all right with you.

MC: No -


RK: Who had written a book about color.


JA: Would you like some grapes?

MC: Uh no thank you.


RK: And we threw the question at him.


JA: So one of the sort of




debates that became interesting to us is this - where is the color? Is it - out there? I mean is this grape that I’m holding right now? Is it red for everything? A bee a whale a - I mean or - is this - does it exist in a in a way that you can pin down and say it’s outside me or does it only get to be red when it gets in my head?

JC: Uh well you can - another - a more severe way to to ask this and I ask this uh whenever I’m giving talks is just - would aliens see it as red or -

JA: Yeah would would aliens see it as red?

JC: Right and and the answer is uh - almost




surely no.

JA: Truth is says Mark - even your dog wouldn’t see it as red.

JC: Uh your dog as color vision has blue yellow and black white.

JA: Really?

JC: Yes.

JA: So what would a world look like to a dog?

JC: I mean if you’ve ever known a guy who’s color blind and 10 percent of men are color blind that’s roughly what it’s lke.

JA: Huh.

RK: Well here’s a question - if a dog and a human and a crow were to be staring at a rainbow would they be seeing very different things?

JC: Yes.


[ambi in]




JA: Now this question that Robert just kind of tossed out during an interview like about how different creatures would see the rainbow. This ended up taking us down a little wormhole. And we ended up actually getting a choir to help us illustrate uh what we learned. But just to set a baseline your normal rainbow goes like this. Starting bottom up.


JA: 3-2-1.




Choir: Red…Orange…Yellow…Green…Blue…Violetttt.


JA: Red, Orange Yellow Green Blue Violet - ROYGBIV. ROYGBIV.




Yeah that -I don’t know why people put the I in there but that’s it.


RK: If you didn’t have the indigo you couldn’t say it though it’d be ROYGBVVV -


TC: That’s why you need the “I” I think just to say the ROYGBIV yeah.


JA: That by the way is Tom Cronin.


Choir: Hi Tom.


TC: Uh I’m what’s called a visual ecologist.


JA: Mark suggested we give him a call. He told us that humans see 7 colors in the rainbow.


MC: In the in the case of the dog -


JA: Very different rainbow.


MC: Uh it’s gonna start off -




Choir: Blue…


MC: Blue - he’ll be able to see blue just fine.


TC: So it would see a rainbow starting with blue.


JA: Same blue we see.


TC: And then grading off into green.


Choir: Green.




JA: Same green as us.


TC: And then disappearing.




TC: The rainbow would end there.


JA: With a tiny bit of yellow throw in.


RK: That’s it?


TC: Yeah so the rainbow would be - only be about half as thick as ours.

JA: Wow.

MC: Um so -

JA: That’s a sucky rainbow, do.g

MC: Yeah.

RK: That’s why when god promised that he would never deliver another deluge and he gave - he made the promise in a rainbow - that dogs just were totally unimpressed.

JA: [laughs] And what is it about the dog eye that makes it see this way?

TC: It doesn’t have red sensitive




photoreceptors, no red sensitive cones.


JA: The weird thing is that the difference between dogs and us cone wise is just one. They have cones tuned to blue and green - so do we. But we have this one extra. Red.




Choir: Red.


JA: Which doesn’t really seem like a big difference, I mean it’s just one cone. But -


JN: To have 3 is so much better than 2.


JA: That’s Jay Neitz, vision scientist.


Choir: Hi Jay.


JN: Because of this kind of multiplicative thing. Red can get mixed with blue.


Choir: Blue


JA: Which makes purple.


Choir: Purple.




JN: Or red can get mixed with yellow.


Choir: Yellow.


JA: To make orange.


Choir: Orange.


JN: And green can mix with blue.


JA: To get teal or turquoise.


Choir: Turquoise.


JN: And that’s how we get about 100 different shades of color that we can see.




JN: So adding photopigment instead of adding just one more color you actually add about 98 colors or so.


RK: All right let’s move on so now we have a crow. Unless you’d like to change the bird.

TC: Right. The crow is not so interesting, cause it’s pretty much like us.

RK: Oh.

TC: So let’s take a uh - let’s take uh - something like a um - a sparrow.




RK: All right.

TC: Now sparrows have ultraviolet vision.

RK: What do they see?

TC: So they see - uh the rainbow starts before our rainbow starts  where we just see sky, it would see an ultraviolet color.




Choir: Ultraviolet.


TC: And then it would see the violet.


Choir: Violet.


TC: And it would see the blue.


Choir: Blue.


TC: And the uh greens.


Choir: Green.


TC: And the oranges.


Choir: Orange.


TC: And the yellow first and the orange and -  


Choir: Yellow -


TC: And then the red and probably would see -


Choir: Red.


TC: Further into the red than us because they have -


Choir: Very very red.


TC: A more red sensitive red receptor than we have.




Choir: Extremely red.


TC: So they see a much broader rainbow. It would start earlier and it would end later.




JA: Woo!


RK: So should we assume that the sparrow is the champion? That that’s the - that’s that’s as high as it gets?


TC: If you’re talking about vertebrates. If you’re talking about ver-

RK: No I’m talking about anything that has a heart and a mind and a - and a body.

TC: Once you leave the vertebrates then oh that’s rough. You’ve got - many animals have much better color vision than the vertebrates do.

RK: Oh really?

JA: Like what?

TC: Butterflies are a great example,




butterflies have 5 or 6 kinds of re- of color receptors. We only have 3 remember.

RK: Butterflies see more colors

JA: [Oh?]

RK: than we do?

TC: Yeah.

RK: so if a butterfly were looking at a rainbow. [laughs] I never thought we’d get

TC: Well you know -

RK: here!

TC: Well they do, I’m sure I mean butterflies are out there when when uh - the rainbows are out - but - see colors we have no names for between the blues and the greens and the greens and the yellows.

JA: Ohh.

RK: So it would go from - ultraviolet it would see that -




Choir: Ultraviolet.


TC: Yup.

RK: Then it would see violet.


Choir: Violet.




TC: And then blue.


Choir: Blue.

JA: And then blue blue green?


Choir: Blue blue green.


TC: Yup.

JA: And green green bluey bluey or whatever?


Choir: Green green bluey bluey.


TC: Right.

RK: And then orange and red and all that?


Choir: [unclear?]


TC: Yup.


Choir: [fades down]


TC: They have very complicated eyes.

RK: Huh.


JA: Okay just to recap.

RK: All right.

JA: Here’s the dog.


[Choir sings with fewer voices]


A: Here’s us, humans.


[Choir sings with more voices / harmonies]


JA: Now the sparrow:


[Choir sings with more voices/ harmonies]


JA: Little bit more bass, little bit more high end so to speak. And finally, the butterfly.


[Choir sings with more voices/ harmonies]




JA: Which is you know - not so far above the sparrow but it’s got more mids in there.


RK: So I’m now thinking butter plo- butterflies get the crown.

TC: Yeah but - then you - if you go onto coral reefs you come across these animals called mantis shrimps.

JA: What are they called? Meta? Like -

TC: Mantis like a praying mantis.

JA: Oh.

RK: Oh mantis shrimp.

TC: The shrimp catches prey using an arm like a praying mantis has.

RK: Oh.

TC: Uh - mantis shrimps are are mostly pretty small about the size of a finger. Some get to be as big as your forearm.

RK: Uh huh.

TC: They’re pretty big animals.

RK: Oh.

JA: I’m actually looking this up right here.




[gasps] Oh my god they’re so colorful!

TC: No they are colorful though.

JA: Here look at this. Oh my god -

TC: No they’re -

JA: they’re just like a - it’s like they’re electric colored.

RK: Yeah they’re like

TC: Yeah -

RK: turquoise or something.

JA: Iridescent. And their eyes are like little cartoon eyes. They’re gigantic!

TC: Yeah. They have 2 really big eyes right on the front.

JA: And you said that dogs have 2 cones, we have 3 - how - how much does the butterfly have again?

TC: Butterfly has 5.

RK: Yeah.

TC: Depends on the butterfly. Uh mantis shrimps have 16.

RK: [laughs]

JA: 16?!!

RK: [laughs]

JA: Oh my god!




RK: Well if you have 16 - uh -

TC: 16 kinds of receptors.

JA: What would the rainbow look like to them? I mean could they even see it?

TC: Mantis shrimp would see a rainbow fine cause they live in very shallow water and so the water is pretty clear, almost like air.

JA: Huh.

TC: They would start the rainbow way way way inside where we see violet - they would see -




Choir: Super duper ultraviolet!


TC: Extraordinarily deep ultraviolet. And then they would go on through several kinds of ultraviolet that probably 5 or 6 kinds of ultraviolet - and then they would get to violet which which is - now they’re reaching our colors




and go through violet and violet blue and blue and blue green -


Choir: Blue green…


RK: Where they have those green green blue blue blues as well?

TC: Yep.


Choir: Green green blue blue - yellow orange-


TC: And then they would go out into the reds. So they would be about about as red as us when they get to the red end.

RK: But only in the reds.

TC: Yeah.






JA: What a rainbow that must be!

RK: Yeah.

TC: They have the most complicated visual system of any animals by a factor




of 2 of more, so -


JA: Wait wait - he said any - do you mean - did you mean - unequivocally any?

TC: Yeah! No other animal that we know of has a visual system within 50 percent as complicated.

JA: All right mantis!




Choir: Mantis shrimp! Hallelujah! Hallelujah! Hallelujah!

TC: But you know on the other hand their brains are tiny, so who knows what

RK: [laughs]

TC: it turns into.

JA: They not have the ability to perceive the beauty of the rainbow in the way that -

TC: No I don’t I don’t -




no they’re they’re - mantis shrimps are into violence, they’re not really into beauty. They go around and and kill things. That’s - I mean really, that’s what they do. That’s one reason they’re so fascinating is -

JA: How how do they know -

TC: They have to go around and kill things.

RK: But what do they kill?

TC: Uh crabs-  other mantis shrimps, shrimps - octopuses.

JA: They’ll kill octopuses?

TC: Yeah small ones. A good size mantis shrimp will - can break the wall of an aquarium.

JA: Really?

TC: Yeah there’s uh there’s ones in California that can break aquarium walls if they hit it hard.

JA: Oh my god.

RK: So you have a pugnacious Muhammed Ali




seagoing animal with incredibly great visual sense!


Choir: [unclear] Hallelujah! Hallelujah! Hallelujah! Hallelujah! Mantis shrimp! Mantis shrimp! The mantis shrimp!


JA: Special thanks to Jim Briggs our engineer for the uh choir session which was a blast.


RK: To Mark Changizi for setting us off in this direction.


JA: To Michael Kershner and the Young New Yorkers Chorus.




RK: And John McClay and the [Greece?] Church Coral Society and those folks from the Collegiate Choral and the [XX?] choirs who joined us.

JA: And to Alex Ambrose of WQXR for getting everybody together.


RK: Thank you thank you thank you.


Choir: Hallelujahhhh.






RK: Okay a very quick update. Since we aired this broadcast - the mystery




of the mantis shrimp eye has just gotten deeper. And we mentioned they don’t seem to gaze at sunsets or rainbows. We now think that maybe they use colors as kind of triggers for particular actions. One color says fight, another color they - eat! Other color says sex. They still have the best eyes in the world but what they’re doing with those eyes is a bigger mystery now than ever.




VF: Start of message.

TC: Hi this is Tom Cronin.

JN: Hello this is Jay Neitz.

Choir: Radiolab




is supported in part by the National Science Foundation -

JN: And -

TC: And the Alfred P Sloan Foundation.

JN: Alfred P Sloan Foundation.

TC: Enhancing public understanding of science -


VF: Science and technology.

Choir: in the modern world.

VF: More information about Sloan.

JN: At www.sloan -

VF: s-l-o-a-n.

JN: dot org.

JG: This is James Gleick. Radiolab is produced by WNYC.

Choir: And distributed by NPR. [someone sings high note]




VF: Okay hope that’s good enough for you.

JN: Bye.


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JA: Hey I’m Jad Abumrad.


RK: I’m Robert Krulwich.


JA: This is Radiolab and today we’re talking about color.


JN: Okay.


JA: And that actually brings us back to Jay Neitz.


JN: I’m a professor of ophthalmology - University of Washington, Seattle.


JA: Jay has actually spent his entire career trying to get creatures to see colors that they normally can’t see.


JN: I - well yeah.


JA: And he started - this is kind of an interesting story uh by taking some color blind monkeys who couldn’t see red-


JN: They have blue cones, green cones, but no red cones.


JA: Which is not unlike a lot of human males.




In any case, he had these monkeys and was able to take the human gene for the red cone - wrap it in a virus-


JN: And - we -


JA: Inject it into the monkey’s eyes and bam!




JA: The monkeys suddenly had red cones.


JN: Yeah.

RK: Oh my god!



JN: So it had blue, green, and red.

JA: Was this like Lasik, so it was just like a a 10 minute outpatient situation for the monkeys?

JN: I would say close. Close to Lasik.

RK: Could they then now see red?

JN: Well every single morning before they get their breakfast they have to do their color vision test.




So -




RK: So he’d sit each monkey at a computer -

JN: We had a touch screen.


RK: And the screen looks totally grey. But - in that field of grey he adds a little red blob.


JN: Right.


JA: Now here’s the key.


JN: We use grape juice as the reinforcement -


JA: For the monkeys -


JN: But -


JA: The game is -


JN: You have the touch the blob before you get your juice.




JA: So before the surgery they weren’t seeing any blobs and they weren’t getting any juice.




JA: Because all they could see was grey so a little red blob could be right there




in front of em and they’d never see it. And the morning after their uh Lasiks’ color booster shot -




RK?: Okay - [XX?] you see it -


JA: They -




JA: Still couldn’t see it.




JA: Day after day they would do their test -


JN: mmhm


JA: And every day they would fail -


JN: Every day they would fail.






JA: No blob, no juice.


JN: But it’s -




JN: fun for them - they get out of their cage, and they talk to their friends and -

RK: Did you fail? Yeah I failed? Did you fail?




JA: I failed. [laughs] Another day another fail.


RK: Until 1 morning




after about 20 weeks. They woke up the monkeys gave them the test -


JN: and they began to not fail.

JA: Really!

RK: Really!




JA: If you watch the video of this it actually looks like the monkey is like -


JN: Wow! You know I’m not having any failures.


JA: And check out this dot! Look at this thing!


RK: Check it out!

JN: So I did get some sense, that they




felt like that their life had improved.


JA: Now if this worked so well with the monkeys couldn’t you take a color blind human and and give them back the thing they’re missing?




JN: Absolutely. We could cure colorblindness in a human with exactly this technique.


RK: Really.


JN: The only thing that we have to do is convince the FDA that the risks - uh - are low enough and the benefit is high enough that it’d be something we could do




in people.


JA: Ha -

RK: Have you tried it?

JA: you’ve never tried it or?

JN: No we’ve never tried it. Although I get a lot of emails that say I don’t care what the risks are. I’ve even had offers - how about if I come to your laboratory and you don’t tell anybody late at night and you give me the shot in the eye and we won’t tell anyone.

JA: Which brings us back to our original question. If you can take a color blind human and give them normal color vision could you take a color see-er and boost em to make em a little more shrimpy?




JN: Well - yes,






JA: He said sure, why not? But then there’s the whole FDA thing but - here’s the real surprise.


RK: Jay says there are some people who are already a little bit mantis shrimp like. There are color mutants if I may call them that in the nicest possible way among us.


JA: Or - they’re out there in theory. Okay so there’s the deal. The genes for the cones in our eyes that see color - you know the red green blue cones.


RK: Yeah




JA: They’re on the X chromosome. Now men as we know only have 1 of those.


RK: Women have 2 X chromosomes.


JA: Which means that women have 2 sets of these cone making genes. Normally one set is just a spare. It’s not used but still they’ve got 2 sets.


JN: And so someone said - aha -

JA: it is theoretically possible that in some women this spare set of genes might mix up - turn on - morph into a whole new cone. A 4th cone!




JN: We’re gonna call it the yellow cone.


JA: So if -




people with normal color vision are tri-chromats cause we’ve got 3 cones.


JN: A woman like that would be tetra-chromat. So all together she’d have a  blue cone a green cone a yellow cone and a red cone.


JA: But she wouldn’t just see more yellow. This new yellow would mix




with the red and the blue and the green to create thousands maybe millions of - more shades of color.


JN: This amazing - technicolor is not the right word. It’s whatever would be the next kind of color that would be even more




super duper.


JA: This was just a though experiment?




JN: Yeah but um -


RK: Jay actually figured out a way to test for this.


JN: We can look in people’s blood and I can say this woman has the gene for blue cones, green cones, yellow cones - red cones.

RK: Oh so you can do a DNA test really.

JN: Yeah.


JA: So he started doing blood tests and he found this one woman -


JN: She worked at the same place we did.


JA: Crazily enough.


JN: At the university.


JA: He looked at her DNA.




JA: And he saw the gene for the 4th cone.




JN: Yeah.

RK: Wow.

JA: So did she see in




JA: super technicolor or - how would you even know?

JN: That was - that was a problem. And so we thought of an experiment in order to be able to see whether or not she had this extra dimension of color vision.


JA: He was able to produce these 2 yellow lights that to us you know - trichromats - normal trichromats - look totally identical.


JN: We’re color blind to that difference.


JA: But to a tetrachromat, a woman with this 4th cone. The would look totally different.


JN: Yeah.




So - I brought her in - I said okay - here it is. Do you see these as different? And she said — no.

JA: No!

JN: I don’t see them as -

JA: No!

JN: any different! But the story doesn’t end there.

RK: Good!


JA: Jay told us about a colleague of his in England.


JN: She’s at Newcastle.


JA: Named Gabrielle Jordan and she apparently found 8 of these women with the extra cone. And out of those 8-


JN: 7 of those women behaved exactly like the




person that I had tested.


JA: Couldn’t see the difference.


JN: But one of them -


JA: Took 1 look at those 2 yellows and said -


JN: No they look totally different to me.




JA: Oh ho! One of these women was - saw the saw saw it as different so one of them had the cone but could use it and the others had the cone but couldn’t use it?

JN: Yup so why is that?

JA: Yeah why?

JN: Well this is the part if you’d like I




could tell you what my theory is of what’s going on.

JA: Yeah.

JN: So I think that -


RK: Jay says let’s just imagine you grow up in a world




without color.




JN: Completely and totally a black and white world. Houses would be painted black and white. Printers would only print in black and white.


RK: Even the TVs -


JN: They would just have black and white TV. Women’s makeup would be just you know - they’re dark or light.


RK: So it wouldn’t make any difference if you had color vision because you would never use that color vision, there’d be no words for color. Now just to make it interesting let’s imagine one day a bright red apple plops




into your world.




JN: How would you react to it?

JA: Would you see it

JN: So -

JA: you think?

JN: Well so that’s a very good question.


JA: Maybe says Jay even though you have the ability to see that red apple - if you’ve never had a chance to use that ability? To practice? It may just lay dormant. And that he thinks might be what happens to women living with the extra cone in our world.


JN: They’re very rarely subjected to colors that would stimulate their extra kind of cone differently.




JA: So you’re saying those other colors just aren’t around enough for them?


JN: Yeah. Everything that we make is based on the fact that humans are trichromatic. The television only has 3 colors. Our color printers have 3 different colors. There’s nothing out there that we make artificially that a tetrachromat could see.


JA: But Jay says maybe -


JN: Some women because they’re just more aware or - because of the job that they do -


JA: Maybe someone who works with color all the time like a florist or a painter.


JN: Little by little -






JA: Because they’re paying such close attention.


JN: Their brain would learn to see that difference.

RK: Huh.


JA: So naturally we wanted to find one of these mythic ladies -


RK: We’re hoping not mythic maybe we -


JA: The reason I say that is because we tried to find that one woman that he mentioned you know the one out of 8 -


RK: Yeah.


JA: And we had a - a really hard time and we began to doubt that she




even existed. And then we began to look online and you see all these websites saying are you a tetrachromat, contact us contact us. Everyone is searching for these women and we we began to feel like we were chasing unicorns a little bit. But then our producer Tim Howard claimed - claimed that he had found one.


GPS: Recalculating.

TH: Yeah you are.

GPS: Turn right on Sarah Street.


JA: He’d been in touch with Jay. Jay told him that he tested a woman, determined that she had the 4th cone and this woman was an interior designer.


RK: Oh.


JA: But Jay had not yet determined whether she could use her 4th cone so we sent Tim to Pittsburgh where she lives.


[door slams]

Fem voice: Hi there.


JA: To see what he could find out.




TH: Hey how are you?

SH: Hi I’m Susan Hogan, I’m a mother of 3 and an interior designer.


JA: What was she like?


TH: She’s great.


TH: Oh you have a juke box.

SH: Uh huh. [laughs] Really - you want me to play something?

TH: How bout number 307? It just seems appropriate cause it’s about color.

SH: Whiter shade of pale. [laughs]




TH: Um she told me




a lot about how she uses color in her work.


SH: - you see the different colors of paint.

TH: Yeah.


TH: Because she thinks a lot about it in terms of painting walls.


SH: I know the way

TH: Yeah

SH: the sun is oriented in a room each wall will look a different color even though you paint -


TH: In any case here was my plan. I’d uh ordered this test before I went to Pittsburgh that Jay had suggested I get -


TH: All right open it open it open it -


TH: It involved these little pieces of brown fabric.


JA: Okay.


TH: They all look identical.


Lynn: They look strikingly the same to me.


TH: Yeah, Lynn, Brenna, me, Soren -




Soren: Those are completely indistinguishable.


TH: Couldn’t see a difference.


Lynn: Do they all look the same to you guys?

Soren: Yes.

Lynn: Okay.


JA: But I’m assuming they’re actually not all the same.


TH: That’s the trick. Jay said if you show them to a real tetrachromat they’re gonna be able to see these subtle differences that you know - you and I can’t see.




TH: And um -


TH: Back to Pittsburgh.




TH: How bout we head over to that tree - is that - that look good?

SH: I need to take my shoes off.

TH: Oh yeah.

SH: Cause it’ll be much more fun [laughs] -

TH: Yeah

SH: for me.


TH: We ended up doing the test in a nearby park.




TH: We’re gonna do a bunch of these if you don’t mind.


TH: In the first trial -


TH: All right


TH: I took out 3 of the swatches. 2 that were exactly the same and one that was supposedly different.


JA: And when you took it out could you see the difference?


TH: No, no.


JA: Huh.


TH: So I go behind the tree and whisper into the mic.


TH: Number 3 is different. Number 3. I hope you couldn’t hear me.




SH: No I couldn’t.

TH: I’ll let you take a look. She steps back from the swatches - gives it a look for a moment -




and then she says -


SH: Number 3.




TH: Third one is different.

SH: Looks more neutral, less red than 1 and 2 on the left.


TH: 1 for 1.


JA: Luck.


TH: So I went behind the tree. I - changed up the swatches. So that now - the middle swatch was the odd one out.


TH: And same same deal ready set go -

SH: Easy. [laughs]




TH: Which number looks different?

SH: The middle one.




TH: Number 2.

SH: mmhm

TH: You’re right.




JA: Really.


SH: [laughs] Yeah.

TH: Wow. Okay.


TH: Then I figured I gotta make it harder. I switched it up and I made it so all 3 are different and I didn’t tell her.




TH: All 3 are different.




SH: All 3 different.

TH: Wow

SH: Green red, less red.

TH: Knocking this out of the park.

SH: Why didn’t I do this well on my SATs Tim?


JA: Wow you found her! I had - I was sure that - that she was not gonna be - there’s no way this test can work.




TH: Well it actually might not have totally worked.


JA: Wait what - did she start to fail?


TH: There - there’s one little thing I didn’t mention.


JA: What?


TH: I brought along a friend.


JL: I’m Jason [Lecroy?].


TH: Painter.


JL: Landscape, still life.


TH: Thought I’d try him out as a control.


JA: Oh cause you were thinking uh - let’s - get someone who likes color but is a boy and can’t be a tetrachromat.


TH: Right.


TH: Okay so.


TH: And uh - when we tried the exact same test with him -


TH: I mean these 3 they look the same, don’t they to you?





JL: I see different.

TH: He was amazing.


JA: Uh oh.


JL: The first one on the left. 2 jumped out immediately.

SH: mmhm mmhm

JL: Number 1. They all 3 look different to me.

TH: Wow.


JA: Was he just as good as Susan?


TH: Yeah. I was a little bit disappointed I gotta say.


JA: And there was nowhere where he couldn’t do it and she could?


TH: No, but I mean I only had pieces of brown cloth! You know?


JA: So it doesn’t prove anything I guess. She still


TH: No!


JA: might be a tetrachromat right?


TH: For all I know! And - there was this one




moment - I know it doesn’t prove anything but I asked her um - I asked her about the sky. And the sky was just that quintessential sky blue.


JA: mmhm


TH: And she was - I was like what do you see? And she’s like -


SH: I see um -




do you see some of the pink in the blue? See I see a lot of pink like among the blue. There’s red in that blue.


JA: She was looking up at a blue sky and seeing red?


TH: Yeah yeah.


SH: Do you see that?

TH: No…

SH: Oh I see so much red like up - and it’s -




TH: Uh it’s kind of a cop out but it’s just kind of that perfect sky blue.

SH: No? Okay that’s - that’s -

TH: Where do you where do you see the reds?

SH: It’s just mixed in there.

TH: That’s cool.

SH: One thing I don’t see is any green in that blue. I just see reds right - especially around like a white cloud [XX?] -


TH: And at that moment I felt like - my sky is boring.


JA: I’m so sorry for you. For us.


TH: I’m sorry for us.


SH: [XX?] I mean how do we know that - any of this makes sense? [laughs] You know that’s




the fun of it I guess.

TH: Yeah.






RK: You know




what we haven’t talked about yet.


JA: What’s that?


RK: Um where do the colors come from?


JA: You mean like -


RK: Like um -


JA: Sky colors?


RK: no no like painterly colors like um like marine blue and and -




JA: Oh like artificial colors.


RK: Well no they’re not ar- that’s the thing. You’d think they’d come from a factory or something but originally they came from the earth.


JA: Yeah.


RK: And and and there’s one story about color that has haunted me hm - for about a - a year and a half. It’s so strange.


VF: Mm.


RK: I don’t know know if




it’s true or not but I mean I I don’t know if even you know -


VF: It was in my book of course! [laughs]


RK: That’s Victoria Finley again. Her book is called Color. And this story starts with - well a particular kind of goop.


VF: It’s a color called gamboge. It’s um - it’s named after Cambodia the French word for Cambodia. And it comes from the sap of a tree that grows in the Cambodia Vietnam Thailand border area.

JA: And this is a yellow color?

VF: Well it’s a yellow color but -




RK: How you get it is




really the stick part.


VF: I mean the way they get it is that they cut a slash [wood cutting noise] in the bark - and then hitch up a tube made of bamboo.

RK: About the circumference of a quarter?

VF: Yes.

RK: And then little droplets of goop come out?

VF: Little tiny droplets of goo.


RK: And they fill up the tube. The same way you know you get maple syrup or rubber.


VF: But they leave it for a couple of years.

RK: Years.

VF: Years. All right so it’s a




really slowwww process.


RK: So slow -


VF: Drop.


RK: That some pretty strange things -


VF: Drop.


RK: can happen in that time.


JA: What do you mean?


RK: Sap has secrets.


JA: Secrets. What secrets.


RK: Well you know - wait a minute. So - after 2 long years. The harvesters come back and each of those tubes.


VF: Is now full of this - um quite um quite like plastic,




it’s sort of it’s got that sort of plastic resin-y kind of feel.


RK: But that’s just the beginning. The resin makes this incredible transformation. Which we actually saw Sean and I.


SC: Hello.

RK: Hi.


RK: Thanks to this guy.


GK: My name is George Kramer, I’m a color man.


RK: He owns Kremer Pigments in Manhattan and he sells this gamboge.


GK: It is an important yellow.




VF: Oh it’s amazing when you use it.


Masc voice: We have it powdered and in the resin form.


VF: Because when you have a look at it -


GK: Okay this here.


VF: It’s just like this




dull - uh [X?] brown color.


RK: Imagine like a - a ball of earwax.


VF: And you think oh that’s not a very interesting color.


RK: Dusky sort of -


VF: That’s like a really boring color. But then you put a drop of water on it.


[clicking noise]


RK: Or you grind it up in a bowl.


RK: A little water.

GK: - [X?] it looks like this.

RK: Oh.

GK: [XX?]


RK: And there it is.


RK: Wow!

GK: There’s a little bit of white-


VF: It’s bright.


RK: Very bright yellow.


VF: It’s bright fluorescent yellow.




RK: Suddenly it’s like pow!


VF: I mean it is - quite an exciting color.


RK: Very very [X?]. Wow.


VF: I I carried one around for ages. Have a look at this color, look how boring it is. Now put a drop of water on it, showing kids, and I was really happy. I even gave it to one kid um who was who was just so delighted. And was only afterwards that I found out that it’s dangerous I mean I I -

JA: Wait it’s dangerous why?


GK: You get bad diarrhea.




IG: When the guys used to chip it in small pieces- there was actually a time built in




from the visit the toilet at least once an hour.


RK: Ian Garrett knows that because he was technical director at this art supply company called Windsor and Newton in England. And here’s what really got us interested in all this. Back in the 1980s, Windsor and Newton would get these shipments of gamboge from Cambodia and they would take it to um - to this production room.


IG: Quite a a dusty area, just had a a table in there -

RK: Big ole table where the workers would sit.


IG: And then they would have this hammer- put the gamboge pieces on this - lump of iron and then -




hit it [hitting metal sound] and




shatter it into into small pieces.


VF: Cause that’s how they make it into a kind of usable sellable paint.

RK: And one day as one of the workers was chipping it and scraping at the resin -


VF: There they were.




RK: They found something in the resin that they didn’t expect.


VF: Uh they found bullets.

JA: Bullets? Like in the hunks of resin?

VF: Lodged in them yeah.


RK: Sometime in that 2 year drip drip process - toward the end probably as the resin was getting thick,






a bullet went whizzing through the air, went thwack! Into the goop -




And stayed there. Actually it wasn’t just one bullet.


IG: There was a total of about a dozen.


RK: And those are just the ones he found lying around the factory. There were probably many more.


IG: They fall into 2 thoughts. There’s a very sharp pointed one about just over an inch long - and then the other type of - a small sort of barrel shapes. Which are about 3 quarters of an inch long. About half a dozen of each. And how they g to there and what they




pass through on the way into the gamboge I’m not sure.




RK: What we do know of course is that those years in Cambodia were years of war and murder - a million and a half people died there, most of them in the killing fields. And that’s the same place where you find the gamboge trees.


VF: I mean it’s shocking really, and it cause it - those were just the random little bamboo tubes on - hanging on the trees. What happened in that grove? What terrible things happened?




RK: The proposition here would be that at some point maybe - cause of the famous killing fields -


VF: mmhm


RK: That some 14 year olds with Kalashnikov rifles after finishing a series of murders or just - shot lots of -bullets?


VF: They would have just sprayed that grove. In order to get into the little tiny bamboo canisters collecting this gamboge.

RK: Yeah wow.

VF: They would have to have sprayed that entire grove with machine - machine gun bullets. And in that year or two years - um - somebody um




- murdered people I should think.




IG: Well I mean they they - it’s not necessarily a battle scenario. It could have been target practice. You see these things hanging on the side of a tree you you you wanna practice your uh - marksmanship.

JA: But there - I mean there is a way in which - there there’s violence in this color. I guess there’s vi - it makes me

IG: Yeah.

JA: wonder about the - does it ever give you pause?

IG: Did it ever give me what sorry?

JA: Pause?

IG: Pause, oh.

JA: Yeah.




IG: Uh…not really. We were too remote - bought it from a guy in Holland who bought it from an exporter who got it from - lord knows where in uh Cambodia.

JA: But the idea that it could have been attached to - to that - bloodshed. Does that bother you at all?

IG: Are you saying - do I think it’s it’s morally acceptable? Is that what you’re asking me?

JA: Yeah.

IG: Um…no it




wasn’t Windsor Newton who discovered these things. These things were damaged by customers.

RK: You’re a hard hearted man I feel!

IG: I had never thought about it until you until you pitched it like that.




JA: As we kept on talking, Ian made it clear, it wasn’t that he hadn’t thought about the violence per se it’s just that - it wasn’t like breaking news to him. They sell some pigments that come straight out of hills that are right in the middle of war zones. Okay. Colors are sometimes soaked in blood.




That’s just how it is.


IG: On the other side of the coin I’ve made it my career in 40 years to make artists paints on the basis that people who paint tend not to make war. It’s a - a peaceful occupation.


GK: That is more or less what they used in the -


RK: And George Kremer who runs the paint shop - he was pretty much of the same mind.


GK: Where is their heart -


RK: You could think of it this way. Imagine the first person to ever find this brilliant yellow. Maybe 10,000 years ago. He’s walking through the




forest after it’s rained and he sees it there on a tree and he’s amazed so he puts his finger into the yellow and then dabs some on his face and he feels instantly beautiful. Like larger than himself.


GK: It is about being related to something transcendent.




RK: And that says George is the other side of the coin.


GK: [XXX?] high or whatever. Therefore you - the [XX?] be used for all sort of






RK: Marriages, feasts, maybe war paint, to feel invincible. Any moment he suspects that needed to be pulled out of the ordinary - and lifted up.


GK: Whether you need something that is bright, something that is beautiful. And - special. And this yellow - gives you something special. It is a perfect yellow.








JA: Thank you to Victoria Finley - her book is called Color, short and simple, to the point.


RK: And to Ian Garrett um - of Windsor and Newton who did not wither




under our withering moral attack.


JA: On the contrary.




Fem voice: This is Amy Lantica from Boston Massachusetts. Radiolab is supported in part by the Alfred P Sloan Foundation.




Enhancing public understanding of science and technology in the modern world. More information about Sloan at






JA: Hey I’m Jad Abumrad.


RK: I’m Robert Krulwich.


JA: This is Radiolab. We’re gonna keep going with our show on colors now with




a story about well -


RK: The color of the sky.


JA: The most beautiful color.


RK: Well. [clears throat]


JA: Well I think.


RK: Except red.


JA: Nah.


RK: Yeah. You gotta -


JA: It’s a story that we find really surprising frankly. And it comes from our producer Tim Howard.


TH: Yes. Hello um -


JA: Who uh heard it from - do you wanna -


TH: Yeah.


JA: set set up who this guy is?


TH: Uh so Guy Deutscher is a linguist and a writer -


GD: - and uh -


TH: I came across his book -


GD: - called Through the Language Glass.


TH: And he tells this one particular story in it that uh - starts in I think 1858.




With this guy William Gladstone who was incredibly famous politician in England.


GD: He was 4 times prime minister in the second half of the 19th century.


TH: Every school kid knows who he is even now.


JA: Mm.


TH: But there’s one thing that not many people know about Gladstone.


GD: Well he was a Homer fanatic.




Masc voice: As the soldiers marched the glean went dazzling from the magnificent bronze, all about through the upper air to the heavens.  


GD: He was a deeply religious man and for him the Iliad




and all this - they were almost like second Bible.


Masc voice: Sipping the black blood, the tall shade perceived me. And cried out sharply -


GD: He read them over and over again throughout his life.


JA: So he was into Homer.


TH: Yes.




And so early on in his career. Gladstone decided to write the definitive history of Homer.


GD: This huge book actually 3 books.


TH: Thousands of pages.


GD: Where he discussed a whole range of of issues relating to Homer and his world.


TH: And here’s the thing - as he was reading - doing his research and everything -


GD: He made this very strange discovery.




GD: That the way Homer talks about color in the Iliad and the Odyssey is extremely odd.

TH: It’s odd?

GD: Very very odd.

TH: How so?

GD: To start with - he uses extremely strange [XX?] colors of simple objects - the most famous one perhaps is -

Masc voice: The wine dark sea.

TH: The wine - wine dark -

GD: The wine dark sea it’s it’s -




TH: It looks like wine.

GD: Looks like wine.




TH: Is it possibly like a - a a poetic kind of thing?

GD: That’s what you would naturally think but the other thing he calls um - wine colored um - oxen.


[oxen noise]



TH: But but it’s more than just wine. Take the color violet which to me and probably to you is like -


JA: Purple - purple?


TH: Yeah


JA: Light purple.


TH: When Homer uses it -


GD: He talks about the sheep.


Masc voice: The cyclops rams were -

GD: And the cyclops caves as having -


Masc voice: A dark violet wool.  


JA: But that’s just fantasy I mean -




TH: But the other thing that he also says is violet is iron.


JA: Iron.


TH: So.


JA: Okay.


TH: Chew on that.


JA: [laughs]


TH: Or how bout this one. What is both the color of honey and the color of uh - faces pale with fear.


JA: Uh no idea.


TH: If you ask Homer those are -


GD: Green.


Masc voice: Green honey?


GD: He didn’t call his forest green, he didn’t call his leaves green - it all seems to be wrong.


TH: And um this was totally puzzling to Gladstone.


GD: Homer was Gladstone’s




absolute hero so he found it difficult to understand or accept why someone who was so perceptive would use such defective terms as Gladstone called it.




TH: So he starts going through the Iliad and the Odyssey again page by page. And he counts how many time each color appears.


JA: You mean like how many times he uses the word black or blue or whatever?


TH: Yeah. And um it only takes a couple pages for him to notice -


GD: The predominance of black of white.




TH: That the term black -


Masc voice: Black days. Black carrion flies. Black blood. Under his black brows. Black black black black black black black -


TH: Occurred about 170 times in both books.


JA: Huh.


Masc voice: White arms. White clad. The white sail. White raft.


TH: Occurred about 100 times.


Masc voice: White white white -


TH: But - red?




Masc voice: A blood red serpent.


TH: Only clocks in at about 13 times.


Masc voice: The red wine to the gods.


JA: That’s a big drop.


TH: Yellow?


Masc voice: Dawn in her yellow robe.


TH: Under 10 times. Green?




Masc voice: His teeth chatter in green fear.


TH: Also under 10.


JA: Hm


TH: And then - Gladstone realizes something crazy. The color blue?


Masc voice: Um…[pages flipping]




TH: Zero times.




JA: What?


GD: There’s just nowhere that describes the color blue in any of Homer’s poems.


JA: He does not use the word blue at all?


GD: No blue.


TH: No blue.


JA: Not even once.


TH: Nope. So Gladstone thought










    JA: Yeah.


    TH: And he started looking in other classic Greek texts too. And there he kept finding all of these strange uses of color.


    GD: Violet hair and things like that.




    TH: And after thinking about this for a long time -


    GD: Gladstone concluded that Homer was colorblind.




    But also that all the Greeks were colorblind.




    TH: Wait he thought all of them were color blind?

    GD: Yes. That they saw the world




    in black and white - maybe with a touch of red.


    TH: His thought was that they were straining to see these other colors that were kind of just outside of their reach. And then - their kid - would inherit that effort. Or their kid would just be a little bit better.


    JA: Oh so that’s how we got color.


    TH: So Homer Jr would be able to see a little bit of yellow cause Homer tried really hard to see yellow and -


    JA: And then Homer the third would be better than Homer the second and so -


    TH: Yeah and then this would happen again and again every generation down




    3000 years to the present day.


    GD: It does seem the only you know the only the only possible explanation.


    JA: That’s ridiculous. That’s ridiculous!


    GD: We know today of course that that there - our color vision goes back probably about 30 million years.


    TH: You know, so like when we were climbing trees.


    GD: Exactly. So um generally -


    TH: People mocked him.




    GD: No one took him seriously.


    JA: So then how




    JA: did people explain the no blue in Homer thing.




    TH: Well so here the plot thickens.




    10 years after Gladstone’s Homer debacle, this other guy -


    GD: A German Jewish, philologist called um - Lazarus Geiger.


    TH: Lazarus Geiger.


    JA: A German Jewish what did he say?


    TH: A philologist which I thought was a linguist. It basically means he studies ancient texts. He finds pretty much the same kind of weird stuff that Gladstone did. But he finds it not just in Ancient Greek texts but all over the place.




    Fem voice: Sorry this one?


    GD: He looked at uh the old Icelandic sagas.




    Fem voice: [Icelandic]


    GD: Ancient Chinese.


    Fem voice: [Chinese]


    GD: Ancient Vedic hymns.


    Masc voice: [Vedic]


    GD: the Bible.


    Fem voice: [Hebrew?]


    GD: And surprise surprise what did he find there?


    TH: No blue.


    JA: Even the Bible had no blue?




    TH: In the original Hebrew.


    BW: [Hebrew]


    TH: It has no blue.


    JA: Huh.


    TH: So what where - what’s this room?

    BW: Right now we’re in the public catalogue room.




    TH: I actually went to the NY public library and talked to this librarian.


    BW: [German]


    TH: Who can speak German.


    TH: [German]


    TH: And we got out Geiger’s book.


    BW: Development history of mankind.


    JA: Wait a second I know this voice. Really?


    TH: Yeah that’s that’s my girlfriend.


    BW: Um my name is Brooke Watkins and I’m a librarian at the New York Public Library.


    TH: She helped me find some very cool passages in Geiger’s book.


    TH: Let’s see it first - let’s do it in German.


    GD: Geiger has this amazing quotation.


    BW: Okay, [German]




    GD: But in the Vedic poems.


    BW: [German?]

    TH: And what does this say?

    BW: These hymns of more than 10,000 lines are brimming with descriptions of the heavens. Scarcely is there any subject about more frequently the sun and reddening dawns play of color day and night cloud and lightening - the air and the ether are unfolded before us. And over and over in splendor and vivid fullness. But there’s only one thing




    that no one would ever learn from those ancient songs who do not already know it. And that is that the sky is blue.




    TH: It gets weirded.


    JA: Mm


    TH: You ready?


    JA: I’m - yeah.


    TH: You all ready for this?


    JA: I’m totally ready.


    TH: All right. Cause Geiger then wondered all right if there’s no blue in any of these old texts then when did blue come into these languages?


    JA: Yeah


    TH: So he did this massive analysis to trace when each color term was first introduced to each language.




    And what he found was -


    GD: The order at which languages seem to acquire these color terms is not entirely random.


    TH: First black and white - every language has black and white. Then when they get their first color term.


    GD: Red always comes first.


    TH: Always red.


    GD: After red it’s always yellow.


    JA: Really?


    TH: Yeah


    GD: And then green and blue only at the very end.


    JA: So black white red green yellow and then blue?


    TH: Yeah.




    JA: And that’s universal?


    TH: Well as people




    discovered more and more languages they found some exceptions. But a couple things held, even from Geiger. Out of these colors red is always first and blue is always last.


    JA: Why?


    TH: Well.


    JA: I mean why would there be an order at all and why would blue always be last?

    TH: Well here’s where you get to the guessing part.


    JA: Okay.


    TH: Guy thinks it might have to do with a couple of things. First - in Homer’s world, you wouldn’t have actually been exposed to a lot of blue things.


    GD: Actually if you think about it blue is extremely rare in nature.


    TH: Blue foods?


    JA: No


    TH: Blue animals?


    JA: Blue animals -


    TH: How bout plants?


    JA: There’s a few blu - blue plants.


    TH: Like what?


    JA: Uh…


    GD: Flowers that are really blue are extremely rare.


    TH: Lot of flowers that we think of as blue - they’re actually -


    GD: Artificial flowers.


    TH: We made them blue. Uh -


    JA: Genetically made them blue.


    TH: Yeah.


    JA: What about blue eyes?


    GD: Blue eyes at the time were in short supply - among the Greeks.


    TH: But here’s where we get to Guy’s main point.




    TH: He says you don’t really need a word for a color until you can make that color.




    Reliably. And the reason that red might have been first is because red -


    TH: Is apparently one of the easiest to produce.


    TH: You can just take a dried piece of red clay and you can use it as a crayon which is why paints made out of ochre go back something like 60,000 years. And blue?




    Blue is the hardest of all. For thousands of years no one had it.


    GD: One exception, the Egyptians.

    TH: Ohh.


    TH: The Egyptians. And they and only they had their own word for blue.


    JA: So that’s it? That’s your answer?


    TH: Yeah.




    JA: Like - tell - no blue dyes, no blue words?


    TH: That’s not interesting?


    JA: I - I want more than that.


    TH: Wait what do you mean more?


    JA: I don’t know - something more to say than just about dyes.


    TH: All right well -


    [music playing]


    TH: Here you go. As I was calling around I ran into something that made me think -


    Masc voice: [X?] is that 2?


    TH: A little differently about Gladstone’s whole theory of color blindness.


    JA: Hm.


    TH: Called this guy named Jules Davidoff.


    JD: Professor of Neuropsychology, London University.


    TH: And a few years back,




    he got interested in this particular tribe in Namibia. Called the Himba.


    JD: The Himba. Like many languages in the world they don’t have a different word for blue.


    TH: You might think of them as like a very poor stand in for Homer.


    JA: All right


    TH: And to make a long story short. Jules went to Namibia. He sat down with a bunch of members of the Himba tribe, whipped out of a laptop and showed them 12 colored squares.


    JD: All identical except for one.


    TH: And there’s actually some really cool video footage of his research assistant doing this. And they asked them very simply -


    JD: Which one is different?






    TH: Now you look at this and you see that 11 of these squares are green.


    JD: A color we would call green -


    TH: Very green. And the other one is blue. This blue one it’s it’s shouting - it’s like hey!! I’m blue! Over here I’m blue!


    JD: It’s easy enough for us to do.


    TH: It’s a no brainer. But the Himba who don’t have a separate word for blue in their language -


    JD: They find this distinction a little difficult.


    TH: When they stare at this screen - they just stare




    and stare -


    JA: They don’t see the difference between the blue and the green?


    TH: No.


    JA: Well is there something wrong with their eyes?


    JD: No definitely not. We completely rule that out. They don’t see color - the individual colors differently.


    JA: But then wait -


    JD: It’s so easy to say they’re seeing different colors to us, and they’re not.


    JA: Well then how does he explain it?


    JD: Okay. When we when we decide to put colors together in a group.


    TH: And then give those colors a word like blue.




    Choir: Blue




    JD: Something happens


    TH: He says what happens is that now that there’s a category for that thing - the thing in the category jumps out. It gets louder and louder to your eyes. The category actually feeds back on your perception - so that you notice it more.


    JA: You’re saying that having the word for blue unlocks your ability to see blue?




    TH: Uh I mean it - that’s how it feels to me and Jules says -


    JD: No it’s not quite that.


    TH: He says without the word you’re still seeing the blue no matter what.




    You’re just not um noticing it. Your your eyes are just kind of glossing right over it.


    JA: So you don’t see it.


    TH: [laughs] It’s hard it’s it’s - it’s harder to spot sees Jules.


    JA: But whatever I don’t quite understand that difference but -


    TH: The blue would not jump out and and say hi five! The way it does with us.


    JA: But if it doesn’t


    TH: Um


    JA: jump out to that extent - then - this is starting to sound very Gladstone-y to me.


    TH: [laughs] Yeah


    JA: I mean maybe he was a little right! Like cause if Homer had no word for blue and the word




    somehow enables the blueness of the blue - then maybe his world was less blue than it would be for us. I mean maybe the blue went through his eyes in the same way but it - perhaps didn’t get into his mind in the same way.


    TH: Yeah blue didn’t matter.


    JA: Wait a second. Do you know where this breaks down?


    TH: Where?


    JA: The [bleeped out] sky! I mean you look up and there’s the bluest blue in the world and then it’s right there above our heads it’s been there since the dawn of time.




    So why wouldn’t blue matter more. I mean why wouldn’t it be the first color instead of the last?


    TH: Well that’s what I thought too and I asked Guy about that.


    TH: Yeah why is the sky blue is is the the the first question that you always think of.

    GD: Exact - allegedly the first question that all children ask.

    TH: Yeah.

    GD: But I wanted to see how obvious or striking this blueness of the sky is. So I decided to make an experiment.




    TH: Guy has a very young daughter.


    GD: About 18 months. She was learning to speak.

    TH: What’s her name?

    GD: Alma.




    I talked a lot about colors with Alma and taught her all the colors including blue. And we would play all these games that that dads play with their children.


    TH: You know pointing at objects.


    GD: I would point at a blue question and ask her what’s the color of this - she would say boo. Boo for blue.

    TH: Oh okay. [laughs]


    TH: Soon enough Alma was a total pro she could identify any color.


    GD: Show me the red object show me the this - and -

    TH: Right

    GD: The only thing I didn’t do and I asked my wife not to do was ever mention that the sky was blue.

    TH: [laughs]




    GD: That was the setup.




    TH: So one day Guy and Alma were taking a stroll and they’re practicing the colors.


    GD: What’s this tree what’s this what’s this - and then I pointed at the sky and said - what color is that? And…she wouldn’t give me any answer.

    TH: Huh.

    GD: Although she had just a second before would - was happily telling me that something was blue and red or green. She just looked up and looked at me incomprehendingly. Sort of - what are you talking about?

    TH: She thought you were kidding?

    GD: Um -

    TH: I think she didn’t understand




    what I was on about.

    TH: Huh.

    GD: In retrospect there was no object there. There was nothing with color for her.

    TH: You’re just pointing into the void basically.

    GD: Pointing into nothingness. So she wouldn’t say anything.


    TH: But Guy kept asking every single time they went out.


    GD: Of course I would do it only when the sky was blue.


    TH: And she would never answer him. And this went on for 2 months.


    GD: And then finally she did consent to give me a color name but it wasn’t blue, it was white.

    TH: [laughs]

    GD: For for a few times she said white and then finally after month and a half or two more




    months she she said blue for the first time.

    TH: Wow.

    GD: But even then it wasn’t consistently blue. So she - then she said once blue - mm no white mm no blue.

    TH: Did she eventually decide though - you know what dad it is blue.

    GD: Well no she never said it this way but eventually when I asked it became consistently blue. So she just would say blue.

    TH: Okay.

    GD: This was for me - really the point where I I could you know convince myself - convince at least my heart that this sort of




    allegedly perfect example of blue um is not -


    TH: not so perfect.


    GD: So you know for Homer who never ever




    probably saw a blue object except the sky and the sea - never had a dad who sort of went on about blue objects and asking what the color of the sky was - the fact that he didn’t lose sleep over it - doesn’t seem so strange. Anymore.


    JA: you know it’s kind of - now that I’ve heard this I’m a little - I’m a little -




    Uh - [rueing?] the moment when when Alma decided the sky was blue. Let her have whatever color she wants it to be. Doesn’t have to be blue.


    RK: Weirdly then color is a loss of innocence.


    JA: Yeah.


    RK: It’s like


    JA: Kinda.


    RK: having something fixed that for a while is just between you and your frenzied heart you know just -


    JA: And the sky is many colors truthfully. On the other hand though - I’m disagreeing with myself now. If we all agree the sky is blue then that’s something we can share - that she can share.


    RK: And then she’s in






    JA: And then eventually she’ll understand you know - this kind of blue.




    RK: Yeah there aren’t blue moons but but there - but you know what one would - you know what one would - you know what it feels like.


    JA: Oh yeah.


    RK: It’s not a happy night.


    JA: Mm mm












    Masc Singer: - call me Mr. Blue


    JA: Still think it’s the most beautiful color.




    RK: I just took red just to be contrary - I’m trying to think what my favorite color is, I don’t -






    JA: I wanna thank all the musicians who uh were so generous to let us use their music this hour and joined in in our covers of the rainbow project.




    JA: You heard Reggie Watts with Rainbow Connection. Barbara Bennery with Over the Rainbow, Lonesome Organist with Green Onions, Nymph with Brown Rice, Yellow Ostrich with Sound and Vision, Rya Brass Band with Painted Black, Nico Mulley with Big Yellow Taxi, Sherwater with Black with the Color,




    Eric Freelander with Blue in Green, Marcie Playground with Whiter Shade of Pale, The Heat with Mellow Yellow, Tao Win with Blue, Snow Blink you just heard with Blue Moon. Dan Deacon right here with Colors. Busmans Holiday, Mr. Blue and our very own Tim Howard, aka Soultero - performing Green River.


    We’ll be doing some cool things with these songs for the moment. Visit




    GD: Hello Radiolab, this is Guy Deutscher.

    BW: This is Brooke Watkins.

    JL: This is Jason [Lecroy?]

    GD: Here’s the notice. Radiolab is produced by - I don’t know how to pronounce this - Jad Abumrad -

    BW: Our staff includes Ellen Horne, Soren Wheeler,

    GD: Pat Walters, Tim Howard,

    JL: Brenna Farrell,




    BW: Lynn Levy,

    GD: Dylan Keefe,

    JL: Melissa O Donnell and Sean Cole.

    VF: With help from Douglas T Smith, Brendan McMullon, and Rafael Bennin.

    GD: Okay.

    VF: Special thanks to Sarah Montague,

    JL: Paul Heck, Nick Capudiche,

    VF: Ryan Levitt,

    JL: Ivan Zimmerman,

    VF: [XX?]

    GD: [XX?]

    BW: Winter Woodie,

    JL: [XXX?] Walter,

    VF: And Carver Throdson.

    GD: Thanks, bye.


    Fem robot voice: [End of message.]






    [THE END]