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Dark side of the eye (Adam Cole/WNYC)

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?


Thomas Cronin, Jules Davidoff, Guy Deutscher, Victoria Finlay, James Gleick, Jonah Lehrer and Jay Neitz

Rippin' the Rainbow a New One

Radiolab rips the rainbow a new one.

Comments [46]

The Perfect Yellow

Jad and Robert wonder if maybe they could add to their color palette. Jay Neitz wondered the same thing, sort of. Take a monkey that can't see red, for example. Couldn't you just give them the red cones they were missing? So he took the human gene for red cones, ...

Comments [52]

Why Isn't the Sky Blue?

What is the color of honey, and "faces pale with fear"?

Comments [127]

Comments [267]

Mike Harrison from placerville, ca


Mar. 27 2018 01:36 PM
dimitri from Todmorden, England

I love your programs! I came to a different conclusion with the results of test on the Mantis Shrimp were the colour of the food button was slowly altered from the colour that meant "no food" to the colour that meant "food". If I understood the test right it took the Mantis Shrimp much longer(i.e through many shades) before the Mantis Shrimp decided that it was close to the "food" colour to go for it. Perhaps because it has so many cones and it sees the colour bands so different that only when it gets really close to the "food" button colour does it actually see that they are close in colour. For example..the Mantis blue blue blue green and the colour blue blue blue green might be as different to it as Red and Yellow(perhaps I exaggerate ;) ) but thats the idea.

Mar. 20 2018 07:41 AM
Glyn Griffiths from UK

Great show. Thanks. I have a completely different theory about the blue conundrum. I disagree with your contributor that says blue is rare in nature. I think the opposite is the case. We live on a blue planet. Anyone that takes photography seriously knows that blue is the predominant wavelength of our natural light. So much so that if we want to see colour clearly in photos we need to filter some of the blue out. Even more so when you go down 10-15ft over a coral reef. You kind of just about see the reds and greens of the corals but all through a blue filter. Pretty much everything is blue. So imagine you grew up on that coral reef under water. You would come up with terms for the subtle colours that made one coral different from another...but you probably wouldn't come up with a colour to name the default colour pervading everything. You wouldn't even realise that your colour perception was so dominated by blue. You may even call an object white, even though to our (above the sea) eyes it would clearly be look blue. To a lesser extent we are the same. Perhaps blue is so pervasive that we didn't notice it for centuries simply because it was the filter through which we saw everything else. Blue was light itself. We just didn't realise we lived in a blue world yet.

Feb. 08 2018 05:09 AM
Lauren from Arlington, VA

I am a long time listener of the show and have praised it to many friends and acquaintances. I always listened through iTunes. I note the previous comment regarding the inability to listen to episodes through the website. I am experiencing a similar inability to stream episodes and, sadly, discovered this after I had shared several archive episodes to a friend who is new to the show. Now I fear she will have a frustrating experience instead of the wonderful one I had hoped for her. I am very hopeful this situation can be remedied swiftly.

Dec. 28 2017 02:25 PM
Wayne from Oyster Bay , NY

For days , have been unable to listen or download shows, either new or old. No matter the device, iPhone or iPad,
what once was a simple process is now frustrating silence and a spinning download wheel.
You must have seen a drop-off on podcast use, it's not owed to the holidays. As a long time listener, ( site user) I can without doubt suggest that someone needs to sort out this glitch.
Again, it's not my equipment, have the newest software and can listen to others without problem, i.e.,this American life on NPR or the New Yorker radio hour.

Dec. 23 2017 04:05 AM

I just love how your podcast is told. The editing is spot on, and the way how you guys ask those questions is inspiring

Feb. 01 2017 07:05 PM

great podcast!

Jan. 09 2017 06:08 PM
Kieran Leopold from US

Late to the party, as usual, but the discussion of perception and catagorizing colors - particluarly blue - made me think of the cognitive bias of frequency illusion (commonly known as the Baader-Meinhof Phenomenon). Guy Deutscher has seemingly landed on the opposite of this phenomenon; the lack of a point of reference or term for a thing situates it in the periphery or outside our need to name or categorize it, or comfortable to lump it in with its nearest neighbor. So what do we call that bias/phenomenon?

Nov. 04 2016 11:51 AM
Neale Hare from Chesapeake Virginia

Radiolab is so interesting, I can't wait to hear it every week. This one and the parasites one are amazing!

Aug. 31 2016 10:41 PM
Francesca Anton from Oregon City, OR

This has been a terrific series on color! I hope many science teachers are using it with their very much inspires the learner to learn more :-)
However, when you have time, it would be fascinating to delve into the whole aura thing....there is a community of people who say they see auras, and I was told at a young age by a very famous person that I was "surrounded by yellow" and very fortunate. Shortly thereafter, completely without any encouragement that I knew of, people began calling me 'sunshine'. I had a friend who lost his wife, and a year later was told his feet were surrounded by purple by a person who didn't know him from Adam, and that it was time to stop grieving and go on with his life, which he did. Is there is substantiation to any of this?

Aug. 25 2016 07:35 PM
Ismael Khan from Chicago, Il

The discussion about the color blue in old languages was very interesting. I speak Pashto, but growing up in the US I would translate from English to Pashto in my head. The color blue was always a problem. I would talk to different native speakers and ask what they called "blue"; I almost always got a confused look. Eventually you would prod people and the majority used the word for "green". Eventually, I did find that some dialects used a word derived from "sky". But this Radiolab episode definitely shed some light on the subject.

Aug. 24 2016 02:55 PM
David Schaer from 30065

While listening to the rebroadcast of this show on color, a question occurred to me. Just as there are hearing aids that will amplify narrow, selected bands of the audio spectrum for hearing impaired people with narrow bands of hearing loss. Has anyone created a pair of glasses with a color-corrected image of the scene in front of the color blind wearer, superimposed on the scene, in the manner of Google glass, to augment the particular spectrum deficit of that individual. Clearly, this would not help people that where profoundly colorblind, but many people could derive some benefit.

Aug. 21 2016 08:50 PM
Pat Dooley

You mention how colors seem to show up in literature. Red is first and most common. And you seemed to say that the occurrences followed down the line of the spectrum with the blue never being mentioned. Doesn't that seem interesting to you that the shorter the wave the less it was seen?

Aug. 21 2016 05:19 PM
Aziz from Cleveland, OH

I was a little dismayed at the cunclusions drawn about the non usage of blue and that it couldn't be seen. In the example of the Namibians it could be possible that they grouped blue along with green. Maybe if it was contrasted with red or yellow, etc.they would have distinguished it.

Aug. 20 2016 06:49 PM
Susan Rogers from Anchorage

Several other commentors have mentioned animals with blue: mussels (indigo dye by the Phoenicians), birds with blue feathers (blue birds, Steller Jays, birds of paradise). I feel you were a bit selective in your examples to illustrate your theory. Blue "paint" from copper or other minerals used by NW Coast Indians also.
Continue the discussion regarding red: I suggest 'A Perfect Red', by Amy Butler Greenfield. When Spanish/Italian explorers brought cochineal back from Mexico, it was initially and unknown? Plant? Animal? Mineral? The book offers a good picture of scientific technologies and exploration coinciding with empires and economics.

Aug. 20 2016 06:22 PM
Mark Brodsky from KQED

Contrary to the report, there are 35 mentions of the color blue in Exodus.
Chapter 26 and 28 have many mentions each (verse 1,4,31,36 & verse 5,6,8,26 respectively) The color Blue is used in conjunction with the Blue Thread used in the Tabernacle. Around 40 years ago research in Israel re-discovered the ancient process of creating this in-organic indigo blue by exposing die from the trunculus snail to UV in sunlight. This is the blue thread ancient Jews were commanded to wear. The process was lost and "modern" Jews switched to white until just a few decades ago.

And the Egyptians used lots of blue, Just look at King Tut's mask

So I find the thesis of this story somewhat faulty, though interesting

Aug. 20 2016 06:00 PM
Amelia Trevelyan from Baltimore, MD

Most of the "scientific" conclusions about color as it relates to ancient and non-western cultures make the same essentially chauvinist mistakes we've been making for a couple centuries at least: the notion that color-based observations must be named by a specific word. Exhaustive anthropological studies conducted early in this century concluded that the native peoples of California had no notion of color because when queried re the color of the same objects, the words used varied from person to person to person. Turns out the reason is (and this is true in virtually all groups studied) only a very few colors, those associated with the sacredness of the four cardinal points, are thought of in the abstract. All others are identified by specific objects or animals in nature, so the words used to identify them change according to the specific experience of the speaker.

Homer wrote down what had been oral traditions. It's entirely possibl, even likely that the early Greeks' approach to color was at least similar to that of the tribal peoples of the Americas To generalize sufficiently to make his meaning clear to all, it would be necessary to limit color references to those that could be appreciated more universally. (The same is true of the Bible and most other ancient texts.) In addition, those texts were all sacred ones, so what better way to universalize their content than to limit references to color to those that were close to natural, but might at the same time reference the sacredness of the text

Beyond that, there are a number of realities that call into question the conclusions of others who spoke. For example, we know that virtually all Greek sculpture was brightly and intricately colored. Traces of the pigments remain. If they saw only in black and white, why might they have bothered, indeed, even been capable of those complex color schemes, carried out in reliefs stretching for hundreds of yards?

Finally, to suggest that there is no blue in nature is absurd. Even discounting the blueness of the sea, there are blue birds throughout Europe and the Americas, and it's pretty unlikely that the fields of bluebells in Texas are the result of human meddling. Took me about three minutes to come up with those exceptions to the suggestion that early people's had no blue in their experience. Careful study would undoubtably produce hundreds, for example, as well as birds and native flora.

Aug. 20 2016 02:41 PM
Joanna from Los Angeles

Jill Bolte Taylor recounts a fascinating color reference in her book, "My Stroke of Insight".

While recovering from a massive left hemisphere stroke, she was working with puzzles to exercise her brain, and to help her sort the task out in her muddled noggin, her mother said (something like), "Think about matching the colors". The moment her mother said the word "color", she started to see color, realizing just then that everything had been in black and white since her stroke.

I LOVE THIS! If you need for me to find the page number for you, I will.

Aug. 18 2016 08:59 AM
Asher from Austin, tx

One of my favorite episodes ever!

May. 03 2016 11:00 AM
Andrew Davies

Good heavens Radiolab! I R Disappoint. Not only are your historical references cherry picked and misleading, but the Jules Davidoff Himba study material is just audio copied from a 2011 BBC Documentary. A Documentary that has recently been exposed as an over-dramatized fabrication no less:

Do Better!

Apr. 06 2016 03:48 PM
Karin from Alsea, OR

This is one of my favorite RadioLab episodes! I've listened to it several times and it still bends my mind. It's really fun to think about color, something so basic to our everyday experience, in terms of wavelengths and neurons. Thank you RadioLab for another great conversation! I hope you make the Mail Chimp goal!!

Apr. 05 2016 11:23 PM
Linda Ann Mahony from ithaca new york

violent analogy (the title) with perhaps hints of homophobia, eh? definitely reflective of a conflation of sex and power.

Dec. 14 2015 05:10 PM
Jenna from Boston, MA

I am curious; if language and color are so intimately intertwined, how to animals with no concept of language perceive subtleties in color? If the Mantis Shrimp does, in fact, respond to various colors with different actions, then we can safely presume it differentiates between these colors (at least subconsciously). But if knowledge of color only develops after linguistic identification of that color, how is the Shrimp able to see and respond to the difference? Is the presumption that the shrimp is subconsciously responding to colors perceived by his or her eyes, but not acknowledged by his or her brain?

Jun. 09 2015 08:37 PM
Suzanna Magnolia from Atlanta

A very high percentage of men report that their favorite color is blue. Yet, nearly all men's heads will turn when a woman in a red dress walks into the room.

May. 23 2015 03:31 PM
Joseph from NYC

While the core argument of this piece is correct--that color and language are intimately entwined--it is inaccurate to suggest that the 'ancient world' did not perceive blue. Blue was a very well known color in the ancient Levant and Mediterranean basin. The dye extracted from the Murex mussel, known as tekhelet in Hebrew, produced a deep rich blue color and was highly prized throughout the Mediterranean world. It was an essential color in Judaism. It travelled with Jewish traders to the Maghreb, where it was used to color the walls of towns like Chefchouen. And it was used by the greeks in temple art and to color domes of small buildings.

May. 10 2015 10:02 AM
Mona Al-Mugotir from Omaha

I am surprised you stated that only Egyptians knew and had a word for blue. Ever heard of Ishtar gate of Babylon constructed with magnificent deep-blue color? The gate was excavated in Iraq in the 1930's and is now shown in the Pergamon Museum, Berlin.

Apr. 23 2015 12:45 AM

Never mind, I'm stupid.

Apr. 22 2015 10:20 AM

This episode never downloaded. It doesn't even show up in my feed. Weird.

Apr. 20 2015 04:18 PM
yuriy holowko from myrtle beach , sc

About the color blue, They said the color blue was virtually non-existent in the ancient world, with one exception the Egyptians. My girlfriend told me that the Babylonian's used a lot of blue tiles in their art ...

Apr. 19 2015 10:53 AM
Aaron Marcus from Berkeley, California

Although I found your entire program about color very interesting and enjoyable, I was surprised and disappointed that the work of Berlin and Kay was not mentioned. They wrote "Basic Color Terms" many decades ago, which reported on their examination of the words for colors used in about 100 languages of today and the past, including classical Greek, which was mentioned in the program. They researched color terms that could be used for any objects, as opposed for special terms that are used for only certain objects originally, like auburn or chestnut for horse-hair colors. Their book, also, discusses the somewhat uniform sequence of color names that occurs in almost all languages: black, white, red, etc. Elsewhere in their writings, they discuss their theory that the color terms are describing the coding of signals from the cones in the retina, through the optic nerve, to the visual cortex, and that the color terms are a way for the human brain to register the growing awareness of the coding combinations coming from the "tetra-cones" of the retina. I don't understand why this important work was not mentioned. It seems like a serious oversight (pardon the punny term).

Apr. 19 2015 10:21 AM
A Listener from Oakland CA

The possible range of human color vision may be greater than we imagine.

When I was back in college, one of the guys down the hall had a TV set in his room. I wandered in one day, and found he was watching a basketball game with the red gamut turned way way up on his TV set. It was unwatchable. So I asked him about it, and he said he simply didn't see it -- he was colorblind to that end of the spectrum. He tuned it down for me, and then proceeded to tell me the following story.

He had been looking for some spare change, so he looked around and happened to find an experimenter at the university medical center who was doing a study on colorblindness. You could join the experiment as a participant for some modest amount of money. So he went over and got tested. The experimenter ran him through the spectrum, and measured his responses. At the end of the session, the experimenter took off the last (violet) filters and turned away. My friend, following the protocol, said "violet", and the experimenter, surprised, turned back and said "you can't see that" -- the remaining light frequency being beyond the normal range of human vision. But he could. There followed a quick verification. The experimenter was obviously intrigued and excited, and wanted my friend to come back for lots more testing. But he didn't want to play a lab rat, so he declined -- and there was never any further scientific data on his case.

It just goes to show that there may be other types of uncommon mutations even in humans that might result in a wider frequency response than most of us can detect.

Apr. 19 2015 03:51 AM
Lach Litwer from Oakland, CA

Is there somewhere to see the artist and track information for musical pieces used in an episode?

Apr. 18 2015 04:42 PM
Brant from Quebec

I have only read Homer in translation, but I too wonder if the original Greek said "wine-dark" or "wine-red". I always assumed it was "wine-dark", and that the metaphor was suggesting the sea was as dark as wine, as inebriating, and as dangerous.

Many years ago one of my sisters returned from a trip to Greece with, among other souvenirs, a bottle of honey that was a distinct shade of green. I have no idea what the bees fed upon, but it was excellent. Maybe Homer's referring to green honey was not so far-fetched as Gladstone thought.

Apr. 18 2015 03:21 PM
Batyah Gottschalk from NYC

The old testament mentions the blue color "techelet" used in the high priest's clothing and derived from a marine creature. It is referenced a number of times in the old testament and also in Jewish prayers.

Apr. 18 2015 01:08 PM
Liz from online

"Ripping a new one" ?????
Watch your language, guys. That's a reference to a very violent act which I do not wish on anyone. You should know better.

Apr. 17 2015 07:23 PM
Stephen Weinstein from Camarillo, CA, USA

The statement that the Bible does not refer to anything as blue is false

Numbers 15:38 uses the word blue.

Apr. 16 2015 12:54 AM
SactoSylvia from Sacramento, CA

Did the ancients have a word for "sky"? In other words, is it possible that your daughter (and her ancient counterparts) didn't identify the sky as "blue" because they didn't perceive it as an object?

Apr. 15 2015 04:01 PM
shafi from Manchester, United Kingdom

Great podcast!

I'd love to have tetra-chromatic vision! You could use it for card tricks, secret notes etc and nobody would be able to see what you see!

Mar. 22 2015 08:55 AM

To Kate from Ontario who asked how to cite this podcast in APA style:

Mar. 08 2015 04:16 PM
Aaron from St. Louis

A thought on grasping how some cultures don't notice blue the same way others do: most people I know, when they see a chrome object, would call its color "silver": whereas a painter would not think of it as having its own color, but would notice that it mainly just reflects the many colors around it. Blue can be like that. Similarly, most people who have not had training in painting/drawing (or possibly photography or graphic design, etc) may not notice the fact that shadows on faces are often painted in blueish tones. When you think of it that way, I don't think it is so hard to believe that some people might not notice a blue splotch among the greens.

Mar. 07 2015 11:18 PM
Egr from poa


Mar. 02 2015 11:08 PM
Sean Feit from Oakland, CA

Fun! A detail on gamboge -- you recorded the guy saying it may have been used for special or ritual moments but didn't mention that it's the dye used for Theravada Buddhist robes in Cambodia! Special indeed. Wonderful.

Mar. 02 2015 05:09 PM
Scott from Georgia

I came to this from a story in Business Insider the title of which implies that people could not see the color blue until recently.

What's really going on is that people could not conceptualize blue until recently. Language and thought are intertwined. The physiology has been there for thousands of generations. Color blind individuals aside, the genes that control the development of rod and cone cells have been expressing themselves for quite some time.

However, the human brain needs to develop two things - perception and conceptualization. How we perceive sensations is largely innate, but how we conceptualize them is more heavily influenced by learning. You grow up in the same universe I do, with the same perceptual abilities, but if your language does not describe blue, you will not learn to conceptualize it in the same way I do. Whether that difference is in perception or conceptualization really isn't important; experience is the synthesis of both. The end result is that how you and I experience exposure to what is objectively the same wave length of light will be remarkably different.

So, the other side of this is why blue enters language so late. I honestly think that George Carlin explained this perfectly when he asked "Why is there no blue food?"

Blue enters late because there is no (or very little) blue food. Primitive hunter gathers were more concerned with Reds, oranges and yellows because those tended to indicate what was poison and what was safe. Early agrarian cultures developed language for greens, ambers, and violet next because those were important to judging the health of crops and whether they were ready for harvest.

It isn't until agrarian economies evolve to support more luxury goods, and perhaps not until they evolve to a point where they can support an entire class of people who are exclusively concerned with luxury and culture that language for blue becomes more wide spread. Egypt was one of the first societies to develop to this point and it was one of the first to develop language for blue.

Interestingly, I think this all kind of has a (tenuous) link to political theory. In 1984, Orwell described a society where language modification was a tool used to control how people think. Remove the word "freedom" from the language and you eventually remove the understanding of the concept and the desire to be free from the population.

Well, if it's true that the presence or absence of the language for describing color changes how individuals experience color, then Orwell may have been right... and if so, perhaps this is a lesson in the danger of political correctness.

Mar. 01 2015 03:50 PM
Wayne from Ensenada, Mexico

But the ancient Bible does have the color blue! Starting in the second book of the Bible Exodus 26:4, 31 36 ...
The Hebrew "tekeleth" apparently comes from the cerulean mussel. The shell is blue which was used to make blue dyes.

Mar. 01 2015 12:32 PM
Paul M from NYC

"The order at which languages seem to acquire these color terms is not entirely random." Red always comes first. Yellow, green, and then blue only at the very end. As most SCUBA divers -- and anyone who has ever taken photographs under water -- knows, colors disappear underwater, and the order is not random. Red always disappears first, at about 15 feet. Then orange at 30 feet, yellow at 65 feet, followed by green at a depth of about 100 feet. At about 165 feet, the last visible color -- blue -- finally disappears. So clearly, primitive languages were formed in shallow water, and as they evolved, they sank. Q.E.D.

Mar. 01 2015 01:03 AM
Martin Ostrow from Cambridge

The Homer story was fascinating but also confusing since there's never any mention that tradition tells us Homer was blind. Not surprising that he might describe "the wine-dark sea", if he never saw the sea at all. And by the way does that phrase, "the wine dark sea" connote color or is it merely a description that the sea is as dark as wine. In the original Greek, is it written, "the wine dark sea" or "the wine red sea" ?

Jan. 31 2015 05:19 PM
Kat from Ontario

This is so interesting! But how do I cite this in apa?

Dec. 14 2014 11:00 PM
Dale Stutches from Philadelphia

Came here from a link, thought it was an hour long remix of the Ice-T song.

Oct. 28 2014 02:08 AM
Becky S. Gatsby from Florida

This podcast was so interesting. It's crazy to think about how humans and other animals see colors so differently. A dog sees Earth in a completely different perspective than a human. This makes me wonder if there are actually more colors than we can see.

Oct. 27 2014 11:55 PM

If someone had a fourth cone, they would know it easily in this day and age: every digital photo or image (e.g. of nature) would look bad in comparison to the real thing, because it only has the red, green, and blue components.

Oct. 26 2014 01:03 PM
Serena from Vancouver

Have you guys heard of this artist who sees 100 million colours?

Oct. 16 2014 08:16 PM

I am surprised you did not talk about Tyrian purple (aka Royal Purple). It would be a great addition to this story.

Oct. 16 2014 07:24 PM
gabecolors from heulo, hawaii

What an incredible hour of storytelling and knowledge! This is my favorite podcast of all-time. The only thing they missed was simultaneous contrast and halation. If you are interested in heightening your color vision-- check out huedoku! Huedoku is color puzzle app coming soon... find out about it and take the quiz on the website.

Oct. 08 2014 07:26 PM
aj from BC Canada

Color + Music = Ken Nordine

Jul. 26 2014 01:00 AM
Marko from Croatia

When I'm taking photos outdoors I allways have to tweek them a lot later if I want the sky to look blue. In the raw pictures it is quite paler. I can see where the little girl was coming from.

Jul. 25 2014 05:16 PM
matty bo-batty from ohio

What the heck are these ads all about guys? Weird stuff to let through the comment board. Anyways, I think butterflies would also see a wider rainbow (UV as well, and other insects and birds too, probably). I don't know why they wouldn't see it like that.

Jun. 21 2014 12:05 AM
Jiazheng Guo

This is a really long radio program talks about the topic I have never thought. “What are color? Where do they come from?” There are many experiments about colors those were very interesting. The Rainbow one impressed me deeply. If I stay in a dark room, I will never think about making a hole on the wall, and never know that a hole on the wall can make a colorful world.

Another experiment was about the forth cones of human beings. There were two ladies have forth cones but only one can see the difference between two yellow. I totally agree with the conclusion that "In a complete black and white world,if you have the ability to see the color but you don't use the ability to practice, it may just lie dormant." We need to practice, so we can make better use of the color to beautify our lives.

The three primary colors, red, green, and blue, are simple, but all the other colors we can see are composed by those three colors. I like the way the host use harmony to explain and express what lights gonna be like when dog, human, butterfly, and mantis shrimps see. Dogs have two cones, blue and green, so the light in their eyes is simple, and butterfly has three more so that they can see more colorful world. Mantis shrimps have sixteen cones so the image is relatively complex and well arranged. The way they use sound to make up the drawback of the invisible through radio can help audiences understand and feel the difference more intuitively.


May. 28 2014 10:45 PM
Alice in wondreland from us

i love redrum

Apr. 03 2014 11:52 AM

My name is Diana Gonzalez from the photo 120 class. Although this was really long I found some parts of it interesting. For example, The way newton used a prism and shut his blinds to make the whole room dark poking a little hole as he waited for the sun to shoot into the little whole creating a "colored image of the sun" as Victoria finely said. Its amazing how someone found something as simple as a dark room and little hole would later on became something so popular that is used around all the world to make memories and shows peoples emotions that can be expressed in a different way. Listening to this radio has really gave me an overview on how photography came to be what it now is today and how it slowly started building up. Even now people use the dark rooms and Film to take pictures and that was a technique created a lot of years ago. I really found this amazing and feel like I know much more about photography.

Feb. 12 2014 01:56 AM
stephanie Romero

radio lab was about someone that kept experimenting about colors. theres this thing called the fourth cone witch is someone that some people have. they can see so many colors then normal people. Like for example a lady named susan can see the sky blue mixed with lots of red. She said she seen red around the white clouds. Not everyone is the same. everyone has different color vision. the guy, that i forgot his name. Its probably mark cheen geez that wrote a book about colors. anyways, he experimented 8 ladys. and 1 out of 8 of those ladies seen the difference in the 2 colors of yellow he was showing. To find those kind of people might be hard. But they got the gift to see things so colorful and beautiful. Like the guy said that was talking, he saw a boring sky because he didnt see any red in the clear baby blue sky. I also learned that dogs cant realy see many colors. Like for example if they see a rainbow first they see blue then green and after the colors start dissapearing. Monkeys cant see red, they can only see the color gray. There are so many colors in the world. Even mixing colors get you colors. Like yellow and red makes orange or red and blue makes purple. Crows on the other hand have a much sensitive red they can see thats more then us. Every experiment he did worked. It took a while but he knew what he was doing. He experimented with monkeys, waited 20 weeks and the monkeys started to see more colors also the color red. and they cant see that. If our world was just black and white, imaganating it, it would be boring. The video made me realized, that people should open there eyes on different colors and pay more attention to it.

Feb. 12 2014 12:53 AM
tom linsley from Boulder CO

In Japanese the bottom light on a traffic light isn't green ( midori) it's blue (au).
The Agean Sea is wine colored. Ancient wine stored in unglazed ceramic pots changed to a dark bluish color. You can still see this in Createn homemade wines.

Feb. 09 2014 07:45 PM
maygday from USA

looks like the mantis shrimp isn't as badass as we expected, but hey... it doesn't change my mind about them

Jan. 24 2014 01:24 PM

Mantis shrimp's super colour vision debunked:


Jan. 23 2014 04:22 PM

I must say, I'm disappointed that they didn't mention Rayleigh scattering.

Jan. 20 2014 07:09 AM
D.Hancock from Stockport, U.K.

I'm not sure the answer to my question is not explained above as there's too much to read, but no-one I've spoken to can explain this -

The colours on my modem were all green as they should be. Then I had a cataract op on my right eye and the lights were now yellow, but still green with my left eye.
2 days ago I had the other eye fixed and now both see the lights as yellow. Not greeny- yellow, but definitely yellow. Why ? And is this normal ?

Nov. 16 2013 07:47 AM
Mat Cauthon

Regarding what you said about the order colours appear in history; With colours such as red and yellow appearing first and blue and violet appearing last. Based on surveys, it seems modern humans tend to prefer blue and violet to red and yellow by a very significant margin, so perhaps there is a link?
Here's my source:
I just saw this and remembered the Radiolab episode. Very thought provoking, thanks.

Nov. 10 2013 11:44 AM
mad dog fish eyes

Strange as it is I see two colors after violet in a rainbow. Violet is followed by a dark turquoise and then a light brown.

Oct. 28 2013 06:28 PM
Rebecca Witzofsky

I know that when the colors change to mostly brown, orange, red, yellow and sometimes gold and pink, the colors are fall colors. They're also warm colors which should have an impact on how you view the landscape. If it was just light blue, black, brown, and white, you'd be cold because of cold colors since it's winter. The color also has an impact on your mood so I think colors matter in the landscape.

Oct. 11 2013 05:08 PM
Antonio Mario from Vinhedo, near Sao Paulo, Brazil.

To Alan from NYC,

About confusing blue vs. green and vice-versa: I have this same problem, and I'm caucasian. I don't believe there's anything to do with race (if your wife was displaying the same problem). A few years ago, I found out I have a small degree of daltonism, which explained my blue/green problem.

That's when I found out there are several shades of daltonism and this one in the blue/green region of the spectrum is one of them. This is contrast to the more common form of daltonism, the one where the individual mixes up the basic colors (eg., red vs. green); I have always had a drivers' license, for instance.

Oct. 05 2013 04:39 PM
perfectbite from West Coast

Did anyone read the Scientific American article a while ago on forbidden colors? It seems that there are undiscovered (glimpsed but as yet to be named) colors.

Sep. 21 2013 05:15 AM
Alan from NYC

I noticed the absence in the story of something that I've observed for many years. You must've come across it, and maybe there wasn't enough time to delve. Anyhow, here's my observation.

I've often noticed that my overseas-born Chinese wife would mix up blue and green. At first, I wrote it off as something peculiar to her, but I noticed it among people in her family and later in Chinese speakers in my business. I suspected a linguistic thing, similar to your stories on perfect pitch and perfect sense of direction. Then I met an overseas-born Korean gal who showed the same trait! So I widened it it in my mind to a whole Pacific-Asian matter. (The American born kids, needless to say, identify colors the same as Euro- or Afro- American kids). I don't know any Japanese speakers, but my curiosity is piqued.

As I said, you probably observed this in your study for the radio piece, and had to leave it on the cutting room floor. But I had to chime in.

Sep. 10 2013 06:30 PM
Art In Milwaukee

A wonderful episode on the perception of color, but no mention of synesthesia? How red-orange is that? Maybe in part 2?

Sep. 09 2013 09:16 PM
Judy N from Middletown, NY

I was surprised to hear a scholarly finding that no ancient peoples other than the Egyptians had a word for blue.
I would be interested in seeing this book, as the Five Books of Moses uses terms throughout the book of Exodus corresponding to different kinds of blue. T'khelet, the blue of the priestly robes, appears most often. It is among other colors used in the robes and, contracting the proposed order in which color words appear in languages, it always appears first in the list. "blue and purple and red," describing the priestly robes. There is also a list of precious stones used in the priest's breastplate and on his shoulders, which includes "avnei shoham," variously translated as onyx or lapis. In the last section of the Book of Exodus a there is a description of a theophany with something that resembles sapphire.

"T'khelet" is the blue dye derived from the scarab, so it could have come from contact with Egyptian culture. The jewel colors imply the existence of mining. But how ancient does the culture have to be to meet this scholar's definition? The Jewish Bible may have been redacted and written down after Homer, but the stories were surely handed down from centuries before him.

I'd be interested in checking Ancient Near Eastern Texts to confirm that there are no mentions of blue in any Akkadian or Ugaritic texts.

Sep. 09 2013 02:33 PM
Defiantscribbler from Winnipeg

Can you please link the version of 'At Last' that played at the end of this episode?

Sep. 09 2013 11:26 AM
Suzanne Gallant from Greater Los Angeles

As an artist, I listened with fascination to your program this afternoon. I think as one learns to mix color, one learns to see more differences. But, I as a Jewish learner, I need to comment on your statement that the ancient texts do not contain the color blue. In Exodus 38, in numerous places beginning with verse 1, blue is mentioned as is blue and purple. As you were making that statement, I remembered back to 2005, when as an adult I studied this text in order to be called to the Torah as an adult B'nai Mitzvah(Bat Mitzvah) at the time I was struck by the serendipity of color in my portion connecting to the artist within me. Thus, when your show was over today, I went back to the text, using the Plaut translation, to confirm my memory of the mention of the color blue. In another portion, the Tallit(prayer shawl) is commanded to have a blue fringe made from a source which is no longer available. In recent years they have found a source, but to this date there are not yet blue fringes on the tallit.

Sep. 08 2013 08:42 PM
Rhoda Auerbach from San Antonio, Texas

I loved the episode on colors, perhaps because I do a lot of graphic design- especially digital. PhotoShop is my 2nd best friend. When someone tells me they bought a car, I never ask the make or model first. It's always the color.
Purple is my favorite color,any shade of it but especially dark lavender and royal purple. As a result, about 10 years ago, I starting getting the lenses of my glasses tinted pale purple. Looking at the world through purple keeps me happy. One day, I printed a graphic that I had created and looked at it without my glasses. I couldn't believe how yellow it was. I realized that the purple tint of my glasses was causing me to underplay the purple of my pictures. Luckily, I had a fix and reprinted it, first adjusting the color output of my printer to include more cyan and magenta. I still do this and am totally happy with the output. I know that a better fix would be to include more purple as I create each picture, but I already have thousands of saved pictures and it's easier not to have to wonder which I've adjusted and which not. Whatever works. -Rhoda

Sep. 08 2013 07:15 PM

Interesting show, though it occasionally veered off into more minor threads. And what an abundance of comments on this blog! I'm surprised the show didn't consider the thousands of color variants or combinations we get in something like Pantone colors or Photoshop type programs. The "color picker" in Photoshop can select almost endless colors with subtle shades to them, so obviously our eyes can perceive extremely subtle color variations within the standard color palette. Some of those colors would be difficult to name, since they combine nuanced color combinations. But it's interesting to click on a color in a photograph, for example, and see what shows up in the square as the color selected; it often looks quite different from the color we perceive as dominant in an eye or other feature in an image.

Sep. 08 2013 04:06 PM
Kitura Main from Bemidji, MN

I work at the Headwaters Science Center In Bemidji Minnesota. We have an exhibit that allows guests to draw a picture by moving the paper and table while the marker stays still. Its a popular activity and blue is the most frequently picked color, yellow is the least frequently picked besides grey and brown. Another interesting color note. We had 2 rabbits. The female was black and the male was white. The vast majority called the black one he and the white one she.

Sep. 08 2013 02:19 PM
B.T. Mendelsohn from Ashburn, VA

Nitpicking the color program (maybe not covered due to time limits):
1. Regarding the color blue not being common in nature, besides the sky there are blue-bell flowers, blue berries, and the indigo plant (the source of blue dye before petrochemicals). Also, for pale skinned persons, there is the color of the blood seen in veins through the skin. I've never been far from shore on the "deep blue sea", but have seen some clear blue water, such as at Greek island beaches in the Mediterranean.
2. Regarding the tribe that could not see a difference between green circles and the one blue one, were they asked what color they called the sky? Or did they live under tree canopies somewhere in the tropics where the sky wasn't visible?
3. Blue-green color blindness is common enough to be part of standard vision examinations, and becomes more prevalent with age, but was not mentioned on the program.
4. Also not mentioned, the difference in the cyan, magenta, and blue three primary colors in transmitted light and the red, yellow, blue three pigments in opaque paintings (in which you see the light reflected after subtracting the colors absorbed (not reflected) as in paint pigments.
5. What colors did pointillist George Seurat paint the blue sky?
6. No mention of the rarity of blue lasers.

Sep. 08 2013 02:17 PM
Michal O from Washington, DC

In the journals of Lewis and Clark, they describe how prized were blue beads among the Indians they encountered - so much so that they could trade huge quantities of food, supplies, etc. for a just a few blue beads.

Sep. 08 2013 01:00 PM

Thanks for this awesome show. I've wondered a lot about colors and the brain ever since the blog, "The Crayola-fication of the World". Great episode

Sep. 08 2013 01:30 AM
Eithne from Bolder

Wasn't Homer blind?

Sep. 07 2013 10:49 PM
Sean from Boulder, CO

Probably one of the most intellectually interesting and stimulating broadcasts I've heard in a long time. Great show! Thank you.


Sep. 07 2013 09:26 PM
Amanda A from Tigard OR

I think its important to note that on they show, they said the Bible yes, but in Hebrew. Not like the NIV or American Standard or KJV

Sep. 07 2013 08:15 PM
John Oberschelp from San Francisco

At 1:00:55 in the program, Guy Deutscher asks his 18 month old daughter, who has never heard the "correct answer", pointing at the sky, "What color is that?"
There is a simple explanation for why she:
1) At first, didn't answer.
2) When she first answered, answered "white".
3) Started answering sometimes "white" and sometimes "blue", usually "white".
4) Eventually answered a uniform "blue".

The explanation: she was right every time.

Here is evidence that the daytime sky is about an even mix of blue and white, mostly white.
This link...
... points to a page that displays the web color for an average of blue and white.
Compare for yourself. It certainly is bluer than the sky on every device I've tried; dramatically bluer than the sky near the horizon.

So the child was asked to pick one color name for something that was about equal parts blue and white, with a little more white.
Over time she learned that people don't want to hear "white" even if it is the predominant color.
They called white with a little yellow, "yellow".
They called white with a little red, "pink".
They called white with a little green, "green".
They called white with a little blue, "blue".

Sep. 07 2013 07:35 PM
BobEddy from Carmel, Ca

amazing concept on the color of blue. I recall reading....maybe in 1776 or The Mayflower, that when the Mayflower sat off the east coast in plain sight for several days while the weather cleared for docking, the native americans did not see it ..... because it was not in the realm of their experience. similar phenomenon.

Sep. 07 2013 07:03 PM
cat from Connecticut

I believe I am a tetrachromat. I work retouching photos and have to discern very fine differences between colors. I also see colors differently from each eye. I dunno. useful for my profession. Didnt realize it was so rare, but there is the Munsell color scale to determine color sensitivity. I usually get the whole scale correct.

Sep. 07 2013 06:33 PM

Hi !! Love RadioLab and am always amazed.

A couple of comments about COLOR:

Homer: I always thought Homer was blind. How did that effect his description of color, or is that irrelevant given all the supporting information about black / white / red ??

Color Blue: One important observation regarding the Old Testament (I am Jewish). Jews are commanded to place 'a blue thread' in their prayer shawl (talis) to remind them of the Lord's commandments. Yet it has always been white in my experience. I asked my Rabbi, who showed me his own (periwinkle) blue thread in his talis. Seems the dye for the blue thread came from a snail (destinctly not Kosher!!) local to the Mediterranean which was believed to have become extinct during Roman times due to excessive harvesting for the blue dye.

But recently a group of them was re-discovered and are now being cultivated to reintroduce the blue dyed thread to the talis !!

It is possible that the color came from the stay in Egypt - as you point out, Egypt was perhaps the one achient culture with the color blue.

Thought this was interesting enough to post !! thanks -

Sep. 07 2013 06:23 PM
Laura H.

I wish I could purchase the soundtrack to this podcast on iTunes.

Sep. 07 2013 05:22 PM
Katy from Rye, NY

I know you read the names of the artists who covered color songs but would you please post the soundtrack list? Such a great show and fabulous soundtrack!

Sep. 07 2013 01:03 PM

I have very unusualeyes with a rare disorder called keratoconus. The cornea warps unpredictably. I have had 4 cornea transplants as well as other major eye operations. The first two transplants failed. During the first, the lens clouded. During the second, they removed the lens at the same time and the iris was paralyzed wide open because it took too long and the membrane behind the lens clouded.

Another operation made an incision in the membrane to allow it to separate so light could reach the retina. My eyes did not develop together and I had severe headaches when trying to use them together. The result was that without a lens or membrane in my left eye, I could see into the ultraviolet with it. Black lights in bars were painful. The sky at sunset was a brilliant magenta in the left eye. I was a photographer, and trying to color correct prints in the darkroom depended on whether I used both eyes, or just the right eye.

Having the left iris paralyzed wide open also gave me great night vision. Over the years, the rods and cones either burned out or my brain compensated for the different colors and brightness and I no longer perceive ultraviolet in my left eye as I once did.

Sep. 07 2013 11:52 AM
Sharon from Seattle

Amazing! How about doing a story about the colors people see when their eyes are closed. Not just the remaining of an image when their eyes were open but colors that appear when your eyes are closed. Most people do not see colors but many do. Why? I have no idea. And when I ask friends they say they do not see colors - all is black. But I do see colors, usually in the purple spectrum, that move and merge and are partial or cover the entire space. Curious. Thanks

Sep. 06 2013 11:05 PM

The color that an object appears is the color that it is NOT. The object absorbs all the colors that it is, and reflects only the color that it is does not have. For example, an object looks yellow because it is absorbing all the other colors and only reflecting yellow, the color that it is not. Also, black and white are not colors. True black is the presence of all colors and true white is the presence of all colors.

Sep. 06 2013 10:02 PM
Nate from NM

Marshall from Charleston, my understanding of the reason violet appears to contain red is this: Although your red, green and blue cones are most sensitive to red, green and blue light respectively, they all have a little bit of sensitivity throughout the spectrum. Toward the UV and IR ranges, of course, this drops to zero. The trick with violet is that on the blue end of the spectrum, green starts to drop off a little quicker than red, and so violet stimulates your blue cones most of all, stimulates some base-level response from your red cones, and does almost nothing at all to your green cones, which the brain misinterprets as "oh, hey, this light has red mixed in!"

It's maybe a bit like how a digital camera will render near-infrared light as a purplish tone - in that case, the sensors that would pick up on purple light happen to have an odd and unintended sensitivity to near-infrared light as well. NIR isn't purple, any more than violet light necessarily contains red, but idiosyncrasies in the system make it appear so.

I don't guess that answers the evolutionary question, but I hope it's half an answer, at least.

Sep. 06 2013 03:35 PM
Marshall from Charleston SC

Hey just wondering- Why do violet and red look like consecutive colors when they are on opposite ends of our visible frequency spectrum?
Wouldnt it make more sense for them to be contrasting?
Is there maybe an evolutionary reason we would want the two ends to appear continuous?

Sep. 06 2013 12:07 AM
Jon from new york

I heard that babies see the world under a blue filter because our brains have to compensate for the eventual yellowing which will naturally occur to the lens later in life. If you point to your baby and say this white egg is white but they see light blue then they will think light blue is called white; and what we call blue would look to be the same HUE as blue (to the Baby) but would look much more saturated. If this was the case, the sky would look "white" until the blue cast went away right? If every time they saw white it looked blue then blue and white would be the same.
As for homer, if he said that one color is the same as another he may not be referring to its hue, hue is a fuzzy term because of how our perceptions are so easily duped to think one hue is another because of the way colors look different because of their proximity to other colors (hues). When homer said the sea was the same color as wine he might have been referring to the way the sea can look really dark and richly saturated. (this whole statement could be misconstrued as well, if in the great distant future the words for dark and richly saturated come to gain some higher or more specific meaning.) Now we consider hue to be the main attribute of color, but this is a much less profound of a spectrum as the light dark transitions we call value. What if Aristotle introduced the idea later, when he said that colors are like the musical notes of a scale. Which then introduced the notion of a complete color spectrum, as well as synesthesia.

Sep. 05 2013 10:55 PM
jess from wisconsin

dark blue by jack's mannequin!!!!

Jun. 06 2013 09:38 PM
ntwk adrs

I am confused as to why Deutscer, in his book, doesn't make reference to William H. Durham, Coevolution: Genes, Culture and Human Diversity, 1991; or at least some of the neurological science he presents therein.

Starting on p218 he makes references to the neural coding of color, especially as related to the lateral geniculate nucleus (LGN) of the brain. (The wiring in our brain favors acquisition of red, yellow, green and blue over the other colors.)

He then goes on to press his theory of primary (physiological) vs. secondary (cultural) values in color evolution...great read for anyone looking further into this.

[link to the berlin/kays color chart!]

Jun. 03 2013 09:03 PM

I've had this question in my mind for quite awhile now, ever since I heard the show, actually. I've been wondering if there are artists who can see more colors and have painted using those colors that the rest of us can't see. And does someone with super color detection see those colors in the paintings, and can they see those colors in reproductions of paintings? Do reproductions reproduce those colors faithfully? And is there a way to examine these paintings (via scanning or x-ray) to show these other colors on the canvases?

May. 24 2013 04:05 PM
Claire from Taos, NM

Check out this webcomic about the cones of the mantis shrimp. Methinks The Oatmeal is a fan....

May. 03 2013 03:31 PM

RE: Adrien: No, not ripping off. He mentioned that he was inspired by this particular radiolab episode, gave proper credit and put links. I was actually brought here by that. :)

Apr. 22 2013 07:46 PM
Adrien from Canada

Are these guys ripping you off?

Apr. 21 2013 07:07 PM
Stew Green from Cyprus

Re The color Blue was not perceived until modern times, BUNK I say ..Here in Greece there are blue butterflies, blue flowers, blue insects, blue birds like peacocks.
- I'll believe everything else but that bit sounded like an April fool to me.

Apr. 13 2013 10:38 AM

If you haven't yet, watch the BBC documentary "Invisible Worlds," especially the second episode that talks about the visible and invisible light spectrum such as ultraviolet, infrared, x-ray, etc. It's very fascinating.

There is a condition called Aphakia where the lens in your eye cannot filter ultraviolet sometimes due to cataract surgery or other anomaly, thus enabling you to see ultraviolet wavelength. Monet was suspected to have it, and among living humans, there is a man named Alan Bradley who sees UV light as bluish purple light and the way he sees the rainbow is totally different too.

Apr. 09 2013 09:09 PM

RE: people do not have a word for "blue" and do not "notice" blue, I would appreciate an exploration of this taking in mind what was presented in the "words" podcast. What would be interesting is to determine if there are other concepts we could test for - like we can test for "left of the blue wall". Just like I wonder about colors I cannot see, I wonder if there are things LIKE "left of the blue wall" that I do not have a command of.

Mar. 25 2013 05:58 PM
Dan McHale from San Francisco, CA

Hey thanks for this show. I hadn't known you'd done one on color until recently. I'm an animator and visual artist. I've been reading up on my color theory. Was exited to hear you talk about Newton, Goethe, all those cats.

I've made a short film about RGB. It's called RGB:

Feb. 05 2013 03:42 PM

The Bible DOES use the color blue. See Numbers 15:38.

Jan. 27 2013 04:58 PM

this is the first podcast that i listen and is great !! congrats.

Jan. 24 2013 10:23 PM

Ever since this episode aired, I've been thinking about color and how we see color and who sees what and I've been wondering one question more than the others. If some people see more colors, say, an artist, wouldn't they paint with the colors they see? Does someone who sees more colors see more in the paintings? It makes me wonder if there is another layer to well known art and what we are missing...

Jan. 16 2013 03:57 AM
Jordan Suchow from Cambridge, MA

Great episode. I just posted a critical essay on it episode at:

Jan. 14 2013 01:39 PM
Stef Savanah from Sydney, Australia

Excellent program.
But it is interesting that no mention was made of the difference between mixing paint colours and mixing RGB pixels (as in colour TVs). And, in the segment with the vision scientist (J. Knights…?) the presenter got it wrong with his interjections of the colour mixtures. The presenter said red and yellow would produce orange – this is correct for mixing paints but not quite right (strictly speaking) for mixing RGB light impacting the colour receptors (cones) in our eyes (since we do not have a cone sensitive to yellow).

In paint mixing the so-called primary colours are usually labelled as red (R), blue (B) and yellow (Y). As every primary schoolchild knows, R + Y = Orange; R + B = Purple; and Y + B = Green. Furthermore, R + Y + B = black (or at least a very dark brownish colour).

In RGB it works like this: R + G = Yellow; R + B = Magenta (a kind of pinkish hue); and G + B = Cyan (some might call it ‘turquoise’). And, R + G + B = white.

Why is this so? Briefly, the key difference between paint and RGB is that paint works by absorbing (i.e. subtracting) light and RGB works by adding combinations of light. So, for example, yellow pigments tend to absorb light that is not yellow (and so reflects the yellow light into your eyes). When you mix pigments you are subtracting some colours and letting the rest reflect. In RGB you are adding light of different colours into the rays reaching your eyes.

In fact for professionals in the dye/pigment industry the ‘subtractive’ primary colours are magenta (M) rather than red; cyan (C) rather than blue; and yellow (Y). These are used in your colour ink-jet printer, for example. Now, the mixing works like this: M + Y = Red; M + C = Blue; and Y + C = Green. It’s difficult to see without a colour diagram, but this is exactly ‘opposite’ to the RGB model.

Of course it’s not that simple (see for example, Wayne Bretl’s comment regarding metamerism and also Bryan Reed’s comment ). More detailed explanations can easily be found in Wikipedia and other online sources.

Jan. 09 2013 08:26 PM
Esa Salminen from Dublin, Ireland

Oh, nevermind. Gamelan - Paint it Black, found it. Thanks again for this episode.

Dec. 22 2012 04:52 PM
Esa Salminen from Dublin, Ireland

Thanks for another fantastic podcast! Does anyone know where to find that cover of "Paint it Black" that starts at 29:17? Or any information about it. Beautiful piece.

Dec. 22 2012 04:50 PM
jamie from scotland

I was wondering can you use orange or a red couler for sky

Dec. 22 2012 08:46 AM
RC from NM

Enough with the choir! It did not add anything for me. I found it very distracting. Consider toning down all the sounds.

Dec. 13 2012 02:11 PM


Nov. 07 2012 02:47 PM
Alex Debkaliuk from Kyiv, Ukraine

Loved it! Fun and informative.

Nov. 07 2012 07:45 AM
Paul Brown from Morogoro, Tanzania

I live in East Africa and have spend the last three years learning and speaking Swahili. It's a dynamic language in that it is a molding of tribal languages mixed with Arabic, given the historic prevalence of trade from the Middle East, especially on the coast and Zanzibar. It even takes some words from the Portugese (for instance "meza" for table).

As you learn the language, you begin to see that the newest additions (strictly modern words) to the language, for obvious reasons, come from romance family of languages. For instance "vocha" for "voucher"; "modem"; "sayansi" for "science"; and "komputa" for "computer".

The word that's been most baffling to me has been the Swahili word for "blue" - "bluu". How can the word for a color not have come from the tribal or Arabic roots of the past centuries. This story helped me think through that a bit more. Thanks!!

Nov. 03 2012 12:19 PM
Keith from AT

So this makes me wonder why blue is such a popular color in modern times. It seems (admittedly anectodally) that the most popular answer among children to the question, "What's your favorite color?" is blue. Is it because it is so rare in nature?

Thanks for a fascinating story. My imagination is wandering wildly now. I have so many more questions.

Oct. 23 2012 11:34 AM
Doug for SF from SF

Colors for kids. Before the 1940s pink was for boys and blue was for girls. Take look at the original Disney cartoons, princes and princesses, royality and the Virgin Mary. Then in the '40s the colors were reversed, pink girls, blue boys.

Oct. 18 2012 04:57 PM
Ron Enoch

When we refer to color blindness are we saying it's just the absence of certain colors or the inablilty to see color at all.

Since blue is such a beautiful and tranquil color why is it associated with lonliness and depression.

Are you saying the colors could be construed as a figment of someone's imagination

Oct. 13 2012 08:15 PM

martha from arlington, the ancient women of lemnos to give it a greek theme where dyers of cloth and other things. but also the bible referrences to colour purple is the murex snail, dye, ounce per ounce valued as silver or gold. But in the ancient world silver was for the temple gold for the dead. purple thread for the tabanacle. is the Khn (Cannanite) term to make purple. Like everything the hebrew did the copied their amorite cousins. but also this thread item is sea silk. fibres of a mollusc. helen of troy, the "Torch" wore silk. ferrel stich.

Sep. 26 2012 01:11 PM

martha seattle , homer supposedly a blind man . of course he's no able to see blue. Ancient greek pottery the blak gloss , you sometimes can see hints of blue in the black. a one % aluminum with aa ferrite (from a colloidla suspension of clays)kiln firing with aromatic hydrocarbons will give you a electric blue. colour.encyclopedia Britannica perception of colour. Now he's one for you science minds. i died on the operating room table, my soul rose up to see these butchers enjoying their work. when i got back in my body, i recalled seeing all this in colour. hard to unravel this one. but interesting none the least. got to love anasthesia, closets thing to dieing besides an orgasm. which is close. the barin flatlines for a millie second. cheers.

Sep. 26 2012 01:00 PM
Charles from PDX

Great programme! It made me think of a fantastic novel by Jasper Fforde: Shades of Grey. The book focuses on a society separated into a caste system based on how well one perceives colour. If you've never read Fforde, I'd highly recommend it.

Sep. 17 2012 04:30 PM

The "I" in ROYGBIV stands for indigo.

Sep. 13 2012 12:48 PM
Debbie from Seattle

Where can I look at the video mentioned about villagers unable to distinguish between blue and green. Is their a link?

Sep. 08 2012 02:55 PM
Robert from Ohio

I have two problems with this episode. First, when they question the guy about his moral compass when using the yellow they are way off base. The yellow pigment was not used as a weapon or culpable in any way. It was a bystander, it was a victim if you will, a witness. In a round about way you could say the pigment Isbell was art. Bearing witness to the terrible scene that must have created it.

The other thing is the last part about the guy teaching his daughter colors. Of course she didn't know what to call the sky, you just explained you didnt teach her blue. That would be like asking someone "who is that person" without ever introducing them. That just seemed like a big flaw in that story.

I found so much of it fascinating though, as with all episodes. I really enjoy the shows.

Sep. 02 2012 04:50 PM
Jbarstow from Westford

I do love the show. Great episode!

My general comment is the brain is adaptable. I.e. the blind person has more acute hearing. It makes sense not to perceive a color difference if it doesn't matter. The brain is really good at filtering noise. When it matters to the dyers and painters, they become aware and able to discern. They grow supernatural powers. Maybe they have tetra chromatic, or maybe just highly tuned. I really want to know which.

Re Cowan weirdo: The show must be accurate science. I have questioned this before - is this true? I do love the show, but it you lie to me it's over.

Re Kai: I have the same diagnosis of red-green colorblind, with your perceptions. I assume red-green is a misnomer. Or maybe we are different? I have the most problems with shades of yellow mixed with red or green. If I ever have to cut the amber wire, I am done. My awareness came from single blinking traffic lights in yellow. "Crap, what do I do with this?"

Aug. 19 2012 02:57 PM
Jenny from Berlin

Have I ever told you how much I love you guys?
Man, I love you so much.

Aug. 17 2012 07:33 PM
just a listener from Ecuador

I once read that the color pink as we identify it was not recognized as a separate color until relatively recently. It was seen as a shade of red. Could the same thing be said about the ancients and the color blue? Might they have seen it as we do today, but have identified it as a shade of purple or black? Also, regarding Homer assigning strange colors to everyday objects, might he have done that as a way to add a mental visual impact to his literary works? Reading about purple sheep causes more of an impression than reading about normal colored ones. Perhaps it was the literary equivalent of the Romans painting their marble statues in brilliant, almost unnatural colors?

Aug. 16 2012 04:10 PM
Scott from Rovaniemi

Just saw a blurb for Stephen Fry's new radio episode of "Fry's English Delight". Much of the content - without actually having heard the episode - sounds quite similar to this Colors episode.

Aug. 14 2012 06:02 AM
Jorge Martin

The perception thing about having a word to be able to notice things is very valid. I recently bought a Prius. Now, I see them everywhere. I have purchased two cars previously (Mazda 3 and Scion xB) and had the same effect. I began to notice these models more frequently because now it is an important object to me. The same thing occurs to me with times (12:34, 9:11, 11:11, etc). Before, these times would not matter to me, but now I have attached meaning to them, I will notice them more often.

Aug. 08 2012 05:53 PM
Pamela Whitman from California

No one has mentioned yet the possible (and obvious?) explanation that color perception and human consciousness have actually evolved over the eons, with light and dark discrimination coming first, then perception of the reds, followed by other warm hues, then greens, blues and violets - and more? Whether this might imply imply a change in actual faculty of perception or a change in the ability of the brain to identify or interpret particular sensory input is a question, but the basic phenomenon is supported and recapitulated on many levels.

We know that a newborn baby is first most sensitive to differences in light and dark. The first perceived color, due to the developing physiology of the eye, is in the red scale - magenta is the color that can be seen from inside the womb. Gradually, the other colors come into the picture, with the capacity to see blue/violet being the last to fully develop.

That this phenomenon should also be demonstrated through history is evidenced by the findings you sited in the program. Early civilizations appear to have used black, white, red, yellow. Early Greeks didn't report an experience of blue. Some researchers believe that the lapis blue used in early Egypt was actually seen as black by the majority of the people, and only the high priests, with more highly developed consciousness, could see the blue.

Goethe's contribution to the understanding of color is HUGE but often overlooked. Aside from bringing awareness to the physiological and psychological aspects of color, he, too, did experiments with the prism and made important discoveries. When he looked at a white wall through the prism, he expected to see all the rainbow colors that Newton had reported as constituting white light, but he saw NO colors - EXCEPT at the edges of the wall and the ceiling or floor. What he saw were bands of color that he called 'border phenomena' - either the warm colors (red, orange, yellow) or the cool colors (turquoise, blue, violet)- these were only visible at the boundary where a light area met a darker area. Where the prism displaced a dark area over a lighter one, the warm colors appeared (like the warm colors of the sunrise through the dense atmosphere). Where a light area is displaced over a dark one, the cool colors appear. I think this is actually the simplest and most eloquent answer to 'why is the sky blue?', since it relates to the phenomenology of color as we experience it every day. When we look at the darkness of space through our lit-up atmosphere (looking at darkness through light), we see all the range of blues. It is for this same reason that we see distant mountains as blue.

The rainbow comes into being when the yellow of the warm band overlaps the turquoise of the cool band in light, producing green. When red overlaps violet on a dark surface, magenta appears, completing the color circle.

Aug. 06 2012 06:45 PM
Jerome S. from Silver Spring MD.

You mentioned the essentially non-existence of the color blue. However, the bible, Numbers 15:37-41 discusses blue thread on the corners of a garment.

Aug. 05 2012 07:13 PM
Lucas from chicago

My name is Lucas. I am 11 years old and I heard your show about colors and I was very intrigued by it. You spoke about coming to the conclusion that Homer was color blind. Well, in my school, we did lots of research about Homer's Odyssey and Iliad. One of the things we learned was that Homer was straight out blind. Couldn't see a thing. When I heard your show, I felt I needed to inform you.
I love your show. You guys are great, and keep it up!


Aug. 03 2012 10:09 PM
scampi from London

I wanted to know if I'm a tetrachromat so I found this test to see how well you differentiate between colours
I don't know how well it works or if you're affected by doing it on a computer screen though.

Aug. 02 2012 05:34 AM
Natalia from San Jose, CA, USA

Is there a transcript of this somewhere? I'm thinking of using this with a high school class...

Aug. 02 2012 12:08 AM
Mark Oursler from Southhold, New York

The tomb paintings as well as the decorative painted fill at Verginia (Philip II's tomb, fourth century BC)a Unesco World Heritage site, indicated that the Greek painters of the fourth century has a rudimentary understanding of the color blue ( By the way, fortunately the frescoes at Santorini have survived from the 17th century B.C. Curiously, these too, indicate that the Minoans, understood and made use of the color blue, albeit in the primitive fashion suited to their limited understanding (see,or.r_gc.r_pw.r_qf.,cf.osb&biw=1600&bih=799&um=1&ie=UTF-8&tbm=isch&source=og&sa=N&tab=wi&ei=_isYUIWUF4bY6wGipoCQCQ).

Jul. 31 2012 03:12 PM
Michael Harmon from Oklahoma City, OK

I'm glad to see the amount of comments on this show because I immediately had questions. When I heard the ad for the upcoming show I was peeked "the Greek's were color blind". Really, this must be a joke! But I remembered seeing lots of pottery black with gold or white etched lines....
Yes Lapis lazuli comes from Afghanistan and turquoise is known in Asia. Yes blue is rare in nature, but not unknown, there are blue feathered birds throughout the world. This "black" that is referred to in the Old Testament could very well be indigo dye from the Indigofera tinctoria plant or Indigofera sumatrana, which was domesticated in India, China and Japan. Absence of something in history doesn't necessarily infer that it doesn't exist. On the plus side the idea that human evolution has changed the eye and expanded our range of seeing visible light is very intriguing.

Jul. 30 2012 09:36 PM
Emma Roberts from Seattle

Perhaps it is true that the early Egyptians were one of the first to have a word for the color blue because of their proliferation of the blue stone, lapis. But I would like to point out that they acquired lapis from trade with Afghanistan (Badakhshan province). Would the Afghans have preceded the Egyptians in creating the word for blue?

Jul. 30 2012 03:36 PM

i won't be able to listen to the Hallelujah chorus again without thinking about mantis shrimp.

mantis shrimp in German: Fangschreckenkrebs.

here's a German film showing the fangschreckenkrebs doing what it seems to do best.

love your show. you always make me laugh.

Jul. 30 2012 01:20 PM
Penn Gwyn from Mountain View, CA

When I studied Homer in school, we were taught that he was BLIND. I can't believe anyone can talk about his use of colours in descriptions without noticing this!

@lulu: I'll definitely be checking out the McTaggart book -- from your summary, it sounds like what she is saying accords well with my own experience of slight damage to the visual-processing parts of my brain.

Jul. 30 2012 12:11 PM

Regarding the brain's perception of color, there are similar parallels with how it processes smell.

Stay in a strong odor for awhile and your brain will "tune it out" over time and eventually you will no longer smell it. We can do similar things with noise and sound.

Perhaps the color of the sky and sea are so ubiquitous that they are ignored unless we have mentally assigned some level of value to their colors.

We see them, we just don't comprehend.

Jul. 29 2012 08:54 PM

I never really thought too much about how I perceive colors until I listened to this show. I knew I had some difficulty in distinguishing colors and I was diagnosed as color deficient last year. But after this show I started to look in to this and I noticed that I only really have trouble distinguishing colors in the green-yellow line. Which is odd because people are supposed to be red-green color blind. But I have none of those problems associated with red-green - but only when I look at those dotted pictures. I have trouble making sense of some of them as if I'm red-green color blind. But in practice I have absolutely no trouble dealing with red and greens. It's only in the odd green-yellow line do I start to see very weird things, like some odd neon green-yellow hybrid type of color. I don't really know how to explain it but it's not your typical red-green color blindness. Where can I go to figure out what this means?

Jul. 29 2012 08:47 PM

I had a friend who was a serious, full-time painter. He saw auras and had many other extra-sensory experiences. When he stopped painting and pursued non-visual art (writing) he started seeing less and less auras. I don't know if his non-visual extra-sensory perceptions decreased (along with using his "physical" vision less), and/or whether other more abstract writing-related (?) extra-sensory perceptions concurrently increased. In any case, this would be consistent with almost any very dedicated interior designer AND/OR serious painter perceiving more subtle colors than the average journalist/ non-visual artist.

Check out the book "The Field" by Lynne McTaggart for an interesting description of how ALL vision is apparently just an holographic hallucination created by the brain, a perception/data-set that is fed/filtered through (from?) the Zero Point Field and back to the brain as a visual perception of the object seen ("accurate" though hallucinatory and apparently dependent on selective perception). Sorry not to be more clear, but I gotta re-read it myself! Perhaps another commenter is more familiar with this book/theory and can clarify.

[[The Zero Point Field is a sort of physical subatomic equivalent of what has been called the "oversoul" or "collective unconscious" or "Akashic Records" (etc.) if I understand it correctly. Amazing that they now have started to understand this from the standpoint of pure quantum physics. I am new to RadioLab - has RadioLab done a "Zero Point Field" episode yet??]]]

to Elizabeth of Buffalo: I had this trouble with my mom and realized it was her older eyes that made the difference. Cataracts cause a discoloration of the lens that affects perception of all colors. Many of my mom's friends make hilarious comments after their cataract surgery, such as, "I had no idea all my windows were so dirty!" Another lady who was nearly blind with macular degeneration got so much sight back with cataract surgery that it gave her vision a new boost and she considered applying to get her drivers license back.

Jul. 29 2012 03:43 PM
Susan Davis from New Jersey

Very Interesting show; After listening to your show, I am left to wonder if I fall in the colorful category. My husband tends to think that I see more colors or differentiate the shades in one color than the average person. On the other hand, he could be color blind and I just happen to be "normal" when it comes to color. He keeps saying I should start painting... just so you know, I used to love painting when I was young (over 20 yrs ago) and was very good with colors that my teacher kept some of my "special" paintings.

Jul. 29 2012 02:14 PM
Philip Rutter from Minnesota

Hi, Bob- I caught this one while driving, usually my only chance. Brilliant. : - )

I found I have something to add, though. I am one of the many American males who are "red-green" color blind; and/but- I had the "why" explained to me when George Wald lectured to the Oberlin Bio Dept. He shared the Nobel for- explaining color vision; give him a google. I described my symptoms to him, after his talk.

For my version, he explained; normal humans have 3 different regions on their retinas, each more sensitive to red, or green, or blue- the regions overlap each other; he drew me a diagram of 3 circles, all overlapping. In my case; one of my pigments is displaced; so it does NOT overlap the other two circles. That, he said; makes the wiring to the brain screwy; so the brain cannot so easily compare and identify the wavelengths.

I can see red, and green, exactly as well as you can. But.

When there is a male cardinal (bird) sitting on a branch near the bird feeder; I will only see that it is RED - after - I see that it is a cardinal. No kidding. Then; it's just as red as you see it (as far as I can tell.) Notice I use the verb "will", not "can". I don't know if I can - because, I don't.

All that, it seems to me; plugs into your attempt to comprehend why people do, or do not, see that the sky is blue. Yes- the brain, and how it has been connected up, is part of the perception.

Having lived with the not-red cardinals all my life (and strawberries, etc.) the observations of normally sighted people not perceiving the blue of the sky; until told it is blue- is truly fascinating. Thanks.

Jul. 29 2012 11:35 AM

RE Newton and the color indigo: In modern Italian, azzurro is distinguished from blu (which roughly correspond to Newton's "blue" and "indigo"). I don't know if this distinction was common to Latin, but if so, it explains Newton's seven-color spectrum. No need for the purported magical significance of the number 7. But as this program implies, language may strongly affect perception. If so, we might want to rescue the color indigo from oblivion.

I agree with the Commenters who draw an analogy with language and the perception of sounds (such as the Japanese difficulty with "l" and "r".) It is known that by age 12 or so, a person's brain is imprinted with just about all the sounds it will ever perceive. Another example is the effect of the Chinese language tones on the prevalence of perfect pitch among Chinese speakers.

Thus culture and language imprint the brain, and this provides a neurological basis for 1) expanded perception and 2) limited ability to perceive outside of the learned range. It may be the same with color perception.

Jul. 28 2012 10:23 PM

Very interesting program. I was surprised that no mention was made of the tradition that Homer was blind. Also, I think Enya's "Caribbean Blue" would have been a perfect end to the discussion of the sky being blue, as it contains the words: "They say the sky high above is Caribbean Blue..."

Jul. 28 2012 07:25 PM
Klaus Nordby from Oslo, Norway

Thank you for an excellently-made and fascinating radio show about color arcana! I'm a color geek, poet and book designer, and I have recently published a book called "Poems Green Purple Blue Red" which some of you might possibly find of interest -- if you like poetry and color.

Sample online poems and a free PDF ebook is here:


Klaus Nordby

Jul. 28 2012 06:36 PM
cpb from Anchorage, AK

Wondered if the researcher on tetrachromats has thought on checking with colorists employed in film making. I have seen womens' names in credits on some movies, and I have heard that some directors insist on working with the same woman over a period of years.

Jul. 28 2012 05:33 PM
Anne from Massachusetts WGBH

Great program. I had to stop my errands and listen. The chorus singing the colors ws fascinating. Was that based at all on the colors people with synesthesia see with different notes? A choral colleague of mine sees all notes in very specific colors, the same colors her brother sees, but maybe not the ones her mother sees.

Jul. 28 2012 05:22 PM
Oil painting Lynn from Saint Paul, Minnesota

For me at least, seeing color was like a muscle that got stronger. I went back to school in my 40's to study classic, realist oil painting. That first fall, I got a critique on my still life where the teacher pointed out a dozen color notes I couldn't see at all. I was sure they'd throw me out as hopeless. Two weeks later, I suddenly saw a subtle green right where he had pointed it out. As soon as I painted in that note, I saw it in two other places. Now my world is full of color I never saw before like pink in tree trunks or green in a horse's coat. One of the teachers in this school's ancestry was Ives Gammel. He said few artists are natural at seeing all the colors in Nature. For most of us, "seeing color is a process of slowly having the scales fall from our eyes." It was certainly true for me.

Jul. 28 2012 05:17 PM
Anna Merikin from San Fran City

With respect to the final piece about the young girl who couldn't tell what color the sky was --

Neuroscience has found that toddlers first see in shades of grey. Color perception comes later, as does development of the foveon, with red the first color-receptors to develop, followed by yellow and, finally, blue-violet.

I am lucky to have my infant memories mostly intact, and I clearly remember seeing the sky as a light grey until about the time I could toddle about.

Perhaps the young girl in the piece was at a time when her b/v receptors were developing.

So, would someone like to speculate as to whether this is also true with cultures?

Jul. 28 2012 05:12 PM
Nancy from Vermont

Really enjoyed the color vision show. Knowing how songbirds see bright colors extremely well (they have more rods, as well as the fourth cone), I made a cat collar with bright colors to help songbirds spot and notice a stalking cat. It worked on my avidly bird-hunting cat--who could no longer catch any birds. And now I sell these as Birdsbesafe® cat collars--and they are being objectively studied scientifically in Australia. I work to further the cause of protecting songbirds from domestic cats. A little googling and you can find us. It's a blast to take an idea and bring a new solution to a wildlife problem to market. Thanks for mentioning the little sparrow!

Jul. 28 2012 05:10 PM
Karen Martakos from Arlington, MA

The section of this episode about a few select women who have an additional cone, allowing them to see a greater degree of color variation, touches on something that I've known about for a while. I am a theatrical costumer. Most professional costume shops have their own dye room and staff textile dyer. Often, they must dye a fabric exactly to match an existing one (to add a panel to an existing garment for repairs or re-sizing). The slightest variation in color will be greatly magnified by the colors of the lights on stage. It must be a 100% true color match. 90% of theatrical dyers are women. One of the things that blows my mind abut these women is how they can easily distinguish between color variations that are imperceptible to most people.

Listening to your guest describe the different shades of swatches, and the pink mixed in with the blue of the sky, sounds just like listening to the dyers try to pick just the right color match. I strongly suspect that your researcher could easily find several more women with this extra cone if he looked among textile dyers.

Jul. 28 2012 03:48 PM

Thank you for this beautiful show of colors.
When I was a kid, I learned that "aoi" was the word for both blue and green in Japanese. That was very confusing for me at the time. After listening to this insightful podcast I found this article that mentions that the distinction between green and blue only started to be more widely adopted in Japan after WWII. Now it all makes more sense to me because I learned Japanese from an expat teacher, who wasn't so exposed to the changes of the language. Nowadays the English words written in katakana as "buru" and "gurin" are also used in Japan.

Jul. 25 2012 09:40 PM
Jack from Venice, CA

Ok, the choir idea was brilliant.

Jul. 24 2012 06:15 PM
Scott from Portland Or

Regarding CMYK. CMYK is subtractive color. We still see color with RGB. CMYK subtracts differing wavelengths of light from an white surface (showing equal mounts of RGB) and give the illusion of RGB colors. The CMYK color gamut is smaller than RGB since its ability to replicate the full spectrum is limited by the purity of CMY. K is only used since there is no pure cyan, magenta, or yellow pigments and together they make a dark brown not black. The amount of money spent on color would boggle the average persons brain.

Jul. 17 2012 11:01 PM
Heikki from Finland

CMYK is missing from the show. Most if not all of the print media we see is done in CMYK, we then interpret the CMYK dots on white with our RGB sensors, but there are different ways of translating RGB to CMYK, so maybe somebody could identify the different mappings from each other?

Jul. 17 2012 09:32 AM
jim ross from little silver nj

You have kind of set up a chicken versus egg conundrum. If blue was imperceptible as a separate color why was it eventually manufactured as a paint or dye. Who would make or could make a color they could not see.

Jul. 16 2012 05:21 PM
Shlomi Noach

Common Blue

Great podcast! (Mantis Shrimp for president!) Some comments though:

As opposed to the claim that blue was a rare color in ancient Greek, here are a few blue things that should have been common:

- As mentioned above: blue water. The distinction between good drinking water (blue) as opposed to still/polluted water (green) would have been an ABC for every human being.

- As mentioned above - the sea. A clear see -- especially around Greece -- is very blue. A stormy sea would be greenish. That would have been an ABC to any Greek seaman.

- And the sky: knowing that a storm is coming by the grayness as opposed to the blue.

- Our veins are blue. We can all see them. Pregnant women have much more distinct blue veins. Can't be ignored.

- A lot of blue in birds. Take the Garrulus bird -- very nice blue on the wings. Very common to the mediterrainean.

- While Blue flowers are rarer, they are by no means rare. Lupinus, Anagallis arvensis are common in the mediterrainean.

- Plenty of blue insects: butterflies, metal bettles. I can't vouch for which of them existed in ancient Greece, but I would be very much surprised if someone were to provde no blue colored insects lived there.

Best regards

Jul. 12 2012 12:00 PM
Jose Gonzalez from El salvador

Homer probably was a sailor as young man and humans who work by the sea, as ussual, was prone to develop cataract, then people not see the ligth reflected from objects as normal, perhaps, that was the motive of his poem.-

Jul. 09 2012 07:06 PM

The Old Testament, besides using the word "tchelet" for blue thread also uses it often in describing the colors of the cloth used in construction the tabernacle. The word sapphire is also used, for example, Exodus 24:10: "...and there was under His feet as it were a paved work of sapphire stone, and it was like the very heavens in its clarity." Seems clear that the authors saw the sky as blue.

Jul. 07 2012 10:54 PM
DavidC from Sonoma County

I *loved* that rendition of Green River at the end of the podcast! Where might I be able to get a copy of it?

Many thanks — DC

Jul. 01 2012 09:38 PM
Martha from Seattle

The last segment about the scarcity of blue in Homer's world really bothered me. Unlike Jad, I did not think of the sky, I thought of the ocean! The Ancient Greeks lived on islands and harvested much of their diet from the sea, which I am sure in those days was much cleaner, and thus more blue, or at least blue-green. I haven't been to Greece, but I hear that even now on some of the resort islands the Mediterranean is striking.
Perhaps instead of a scarcity of blue "in nature" such that Homer hardly ever saw blue, Homer was surrounded by it with the ocean. It was such an elemental part of his world that in a sense, he took it for granted.

Jul. 01 2012 12:37 PM
Mike Holland from Sxphw, NC


I've read all 99 previous comments and found no mention of "evolution" or "natural selection" so please let me suggest a future "short" focusing on what this great episode lacks:

A discussion of the REASONS for the various color reception potentials in different species... A reason for different cultural perceptions of color...

... That is, if Bob Kruel-witch can handle this kind of grown-up, adult discussion about WHY we color our world and not just sit around on his
Barker lounge watching the clouds and thinking "God did it. Now, Pass me a another cold Ensure"

Jun. 28 2012 11:11 AM

It seems to me I've heard that story about Goethe on the show in the past, but I can't remember in what context. Has Jonah Lehrer told that story on Radiolab before? Or maybe it's from a lecture that Malcolm Gladwell gave a couple of years ago?

Jun. 27 2012 11:17 AM
Wayne Bretl from Lake County, IL

The experiment with swatches that appeared flawed when the non-tetrachromatic male could distinguish them needed further investigation. He may have had a variation in his cone sensitivities from the usual by having one of the gene variations that tetrachromats have multiples of. This could have conferred the ability to distinguish differences in the spectra of the swatches that "normal" trichromats could not, a situation known as failure of observer metamerism (usually incorrectly shortened to "observer metamerism"). Metamerism refers to several related phenomena: different object spectra looking like the same color to an observer; or to different observers; or under different lighting spectra. It is the fundamental basis of color reproduction with a small number (usually three) of primary colors.

Jun. 27 2012 09:21 AM
Alex B.

Someone already mentioned Mesopotamia, where one of the defining features of the ancient ruins are the blue tiles. Still, interesting.

Jun. 25 2012 08:59 PM
Patricia Kimball from Almaty, Kazakhstan

I loved the way you used music to explain the different rods we use to see color and how they work together. I thought the method was creative and effective. What a great way for a radio show to explain and issue of sight (one of the senses you do not use while enjoying Radio Lab). Well done!!!

Jun. 23 2012 12:29 AM
What about Iten and Albers? from Mississippi

I was excited to learn that a RadioLab episode was to cover color, but was disappointed to hear no mention of Bauhuas artists' experiments with color. I guess I was listening as an artist and not a scientist. I find Albers' experiments with color to be a powerful lesson in color theory. To bad they did not discuss those (at least) briefly.

Jun. 21 2012 05:19 PM
Rohit from London, UK

Discover magazine has a new article around this podcast's theme.

Jun. 19 2012 05:11 PM
Andrey Revyakin

Come on, guys. Could not get a mezzo soprano and a basso profondo for UV and IR, respectively? :)

Jun. 17 2012 02:15 PM
Jon from California

Since someone accused Chava from Jerusalem of being an irrational Christian, when that name and location say Jewish to me, and since I am a Hebrew teacher myself, I can tell you that while tekhelet may mean dark blue, it means blue. To say there is no reference to that color in the Hebrew Bible is not correct, even if tekhelet isn't 100% coextensive with our blue.

It has nothing to do with a religious reading. The occurrence in Numbers 15:38 is recited by religious Jews twice a day, yet almost no logins Jews now wear the blue thread in their prayer shawls. It is specifically the color of a die made from a certain sea snail, and it is blue.

The more likely case is that the religious reading is the one that has deemphasized the meaning of this word as blue to justify the continued custom of all white tzitzit.

Jun. 17 2012 01:24 PM
Lars from Copenhagen

Can someone tell me the name of the opera piece playing at around 05:15 - 05:40, before the segments?

Thanks, Lars

Jun. 17 2012 09:50 AM
Punch Yourself from Santa Monica, CA

Here's something funny. My wife is one of those people who can tell subtle differences in color which is why she's done graphic design for all these years and yet, she can't see 3D...Like 3D glasses stuff, not that she can't see relative space... I spoke with my boss who is going to the Olympics to work on their 3D broadcast and he told me that some ridiculous percentage of people cannot see 3D using 3D glasses. I wonder if the tetrachromatic people have similar issues seeing 3D.

Jun. 16 2012 04:29 PM
Jason Brown from Minnesota

The part where 'blue' didn't pop out from the green squares to the tribesman who didn't have a color for blue confirmed a notion I arrived at whilst observing my toddler son learn language. Around 12-14 months old, he knew 10-15 words, one of which was bird. He would spot quickly spot the bird in any context: a little bird in a long, complicated wall size mural in a Chinese restaurant, on top of a building outside a large shopping center as we are getting out of the car, etc.

It wasn't that he spotted birds that amazed but how quickly he did it. Almost instantly he would see them. I figured as he knew so few words, those he know must jump out at him. He didn't know the words for anything in the Chinese mural but amongst all that 'visual noise' of things he didn't know the names for, the small bird just have stood out like it was flashing.

Jun. 15 2012 01:01 PM

As a former Anthropology student, I can say that RadioLab is right on with their final segment about what colors are named in different societies and the order they are named in-- it is a very hard concept for people in this culture to grasp or believe. I had never heard the Homer evidence, but rather Anthropological evidence from documented research in many different culture groups. It is true! But the answer they provide-- the sky isn't really quite blue, is fairly bogus. It may be easier for us to grasp the reality of the situation with a small caveat-- linguistically these culture do not have a word that means "blue" and nothing else, but they do have the ability to describe the color of objects through comparison. So, rather than saying "green," they would say-- "color of leaves." It is the leap from description through comparison to a unique color word that is the important transition.
It has been a number of years since my Anthropology days, so I hope my memory is accurate.

Jun. 13 2012 10:53 AM
Michael Kilfoy from St. Louis

As always, great episode. I had a couple of thoughts I wanted to pass on.

The first had to do with the cones in our eyes and in the eyes of other species. As the number of cones increased, the aural comparison was a more robust sound. I'm not sure the extra cones produce just a fuller vision in the visual light spectrum.

I think it's safe to assume that the cones measure waves of some sort, the different cones measuring wavelengths. But could it just as well be heat, or something out of the normal light spectrum, as opposed to variations in between. Would it be too absurd for them to possibly see x-ray, microwave or radio waves? If we could see these, what would our experience be?

I've heard some species, such as frogs, are more adept at seeing movement. Could these extra cones help them do this? It strikes me that the Mantis shrimp with it's 20 eye cones, it's tiny brain (to process the visual info) and it's propensity for aggression, that it's sight may be better suited for seeing movement and reacting to attack. Obviously, this is all a guess.

The whole point is that I don't see having extra cones as being equivalent to creating a more robust sound. (After all our spectrum of sound is limited, too. By comparison, what do dogs hear?) It may just be that having extra cones as seeing differently than we do, as being perhaps totally foreign to our experience and largely just unknowable. How would explain site to someone who can't see? Both hearing and seeing and properties of interpreting spectrums of wavelengths.

On the part of the episode having to do with Gladstone and Homer. I found it interesting that the most obvious reference to blue was entirely missing, and that is water. Much of Homer's Odyssey takes place at sea. My wife is from Turkey, which much of was ancient Greece, and the water in many places there is very blue, much more so than the blue of Lake Michigan near Chicago, where I am from.

I happened to listen to the podcast as I often do on a bike ride. And as ride down the treelined trail that I rode and passing maybe hundreds of shades of green, I realized that I am totally incapable of laying claim to all the variations of color. I'm a designer and I probably deal with color, or think about it at least, more than most people. Having a description for every color, or anything visual is daunting. (Just look at the image results in a Google search.) Not having a word for something does not mean it can't be seen or noticed.

Lastly, thanks for doing what you do. I enjoy it immensely. It is the one show I set aside time to listen to.

Jun. 13 2012 02:01 AM

I was disappointed that the pitches sung by the choir did not correspond to colors they were interpreting. At least, the choir could have used lower notes for colors closer to blue/purple and higher notes for those closer to red (or vice versa)as colors on a spectrum would be closer to one side or another. Ideally, they would have used the partials of the harmonic series, to add this dimension of aural "color"!

Jun. 12 2012 02:31 PM
Frederik from Copenhagen

have you guys ever seen a picture from Greece. The ocean can be so blue, that it almost looks unnatural. Hence i don't buy that people in ancient Greece hadn't been exposed to the color blue

Jun. 11 2012 11:04 PM

Excellent episode! I was fascinated by the thought that color might be something that is learned culturally... as a non-native english speaker, I could not help to draw a parallel to sound. Any 5 year old could tell the difference when pronouncing of the letters "V" and "B" or "Y" and "J", but to my untrained ear the sounds were exactly the same. You could hear the words 100 times, but you wouldn't get it. Then one day that part of your brain suddenly "turns on" and it never goes away after that.

Jun. 10 2012 11:58 PM

When you reflected on the story of the little girl who slowly came to see the sky as blue, you lamented her loss of innocence, as if naming the sky blue forever limited what she could see in it. I look at this experience of naming differently. My very first memory is of recognizing--I mean really realizing--that the sky above me was blue. It didn't feel like a loss or a limit; it felt like pure joy. Maybe something was lost, but so much more was made possible by that connection.

Jun. 10 2012 11:03 PM
Mary Kay Stam

RE: Gamboge Yellow...I thought it was strange that two of the men interviewed stated that painters tend to be peaceful. Hitler was a painter.

RE: the linear properties of color vs. the color wheel — the wheel is imposed as a cognitive method of understanding, don't you think? As a way to see how our perception/colors change in regard to each other.

They talk about the Bible being originally in Hebrew — I thought the scrolls were originally Aramaic.

Jun. 10 2012 04:52 PM
William Clifford

William Harris' brief article on Homeric the purple.

Jun. 09 2012 06:00 PM

Technically the sky is not blue, it is purple. It is just the way our eyes perceive color that makes it appear blue. Here are some sites that discuss this a little more:

It's kind of neat to think about how few things are actually blue in world, including the sky.

Jun. 09 2012 01:07 PM

I've been reading everything I can find on mantis shrimp since I heard the podcast. Latest bit is an article in the LA Times about the shrimp's claw structure endowing the claw with super strength.,0,4257556.story

Jun. 09 2012 10:33 AM
Susannah from Albany, NY

I really enjoyed the "Colors" episode. One issue: There IS a mention of the color blue in the original Hebrew of the Torah (Five Books of Moses). You can find it in Numbers 15:38 in the directive to die four threads of one's "tzizit" a certain color of blue called "Techelet". It's also mentioned in Exodus in the description of the Temple. Sages dispute the exact variation of blue. But they agree that the die originates from a certain snail that nobody can located in the modern day.Hence, very few people wear their tzitzit with "techelet" threads. A few intrepid souls take their chances, though.
Another blue in the Torah is "Sapir", referring to the sapphire stone in the High Priest's breastplate. You can find that in Exodus 28:18.
In Exodus 24:9, a description of a glowing blue "Sapir" image of G-d himself appears to Moses and Aaron.

Of course, the whole rainbow is in Genesis! And that same imagery is in many ancient Mesopotamian stories. Thanks!!

Jun. 08 2012 04:22 PM

This may seem like a silly question, but isn't it odd that the two creatures mentioned as having the most color receptors, butterflies and the mantis shrimp, are also very colorful themselves? Any connection? Evolutionary reasons?

Jun. 08 2012 09:48 AM
Adam from Massachusetts

Fine, sky isn't blue it's just sky. And other examples of blue are hard to find. But what about green? Green is everywhere. But you said black, white and red are first. How long can you walk around and not see green?

Have you ever put on those colored ski goggles before? When they go on, everything looks yellow. Then after awhile, everything looks normal through them. Then you take them off and everything looks blue. What's causing that?

Jun. 07 2012 04:11 PM
Ivo from Czech Republic

Hi, very interesting episode. Particularly that part about ancient civilizations and how did they perceive colors. It has recalled me of something similar - tastes and flavors. We also learn flavors when we are young: this is salt, that is sweet, this is how potato tastes, this is how strawberry tastes, and this is how kiwi tastes etc. - depending on which part of the globe we grow up. But see what happens if you let somebody from let say Western Europe taste an exotic fruit as rambutan or something like this. You may ask if he likes it and how does it taste and probably he will describe the taste using flavors he already knows. It tastes like blueberry with banana and vanilla ice.....NO, it just tastes like rambutan :-) you may response then.

Jun. 07 2012 02:19 PM

Interesting link between the Homer/blue section and with the Episode "Words" from Season 8. The rats could not use the blue colored wall to find the food. That episode based the lack of success on rats and language. Is that related to phenomenon in this episode?

Jun. 06 2012 08:15 PM
kkrr from home

interesting start
"lets be friends but money first" :)
good show anyway

Jun. 06 2012 07:17 PM

i'm suprised y'all didn't talk about mary;s room

Jun. 06 2012 12:54 AM
Gabriel from Mexico

Very strange that you didn't mention Homer's constant exposure to two wide, huge blue things above and below his horizon: the sea and the sky! Also, very strange that you couldn't explain correctly why seeing blue is different to having a conceptual category for blue - those guys simply saw the blue spot as something between green and violet, what is so strange about that? Congratulations on the first section with the choir, that was splendid!

Jun. 05 2012 07:41 PM
Brandon Kellogg from Denver, CO

I found the segment where Newton pokes a knife into his eye and finds an explosion of colors, but perhaps more interesting to me than the presence of color in these hallucinations is that, in my experience, these colors are often represented in geometric and sometimes symmetrical shapes. What is that all about?

Jun. 05 2012 06:44 PM
Justin Wheeler from State College, PA

A fascinating site showing "what bees see". Even experts disagree on what colors bees see, but is knownthat they see the UV spectrum.

Jun. 05 2012 04:51 PM
Carla G.

I love Radio lab. The choral music was amazing, a very smart and creative way to illustrate and animate the show.Great idea!!! " why isn't the sky blue ? was my favorite!!

Jun. 05 2012 02:34 PM
Stefan from Miami, FL



Jun. 05 2012 01:42 PM

Fascinating episode! I've always wondered about the subjectivity of color - whether the "red" that I see is the same as what others see. Seems to me that color is just a label we attach to something we experience internally. Suppose some color altering filter was surgically attached to eyes of a new born baby. It would grow up learning, or associating color labels to things ("roses are red, violets are blue... ") but what s/he observes as red, we know, isn't the real red (but it's red, as far as s/he's concerned). Douglas Hofstadter deals with this subject - "problem of the inverted spectrum" in Ch. 23 of I Am a Strange Loop, but I wasn't really satisfied with his explanations.

Jun. 05 2012 01:10 PM
Carl from London

'Redeeming Indigo' by anthropologist Michael Taussig. A must read, in my eyes, when talking about blue especially in the colonial/postcolonial context.

Jun. 05 2012 06:56 AM
Albena from Boston, MA

Dear Jad and Robert,

I love your podcast and am a regular listener.

I also hooked some of my friends on it, so now we have our extra nerdy discussions and shared opinions/knowledge. Special thanks to the super informative, entertaining and memorable style of presentation used in your show. I can’t wait for you to visit Cambridge/Boston, where you will get a unique and insightful crowd.

I am in the middle of the COLORS episode and I have a comment to Dr. Jay Neitz’s part of it:
One possible explanation to why most tetrachomats (those rare women) might not perceive the extra colors is because the green and red opsin genes are located on the X chromosome. In females one of the X chromosomes is usually inactivated/ functionally silent (Xi), while the other remains active (Xa). So if there are gene changes leading to a fourth opsin (cone type) then it is very likely that that new gene will be now in a heterozygote state with the wild type (original gene) it has derived from. Consequently only one copy will be expressed.
I can think of 3 theoretical reasons why sometimes these tetrachomats might report different color sensitivity compared to the “normal” trichromats:
1) not all photoreceptors in the eyes inactivate the same X chromosome
2) the inactivation is not complete and there is expression from both gene alleles
3) the gene has migrated to a new location (for example possible duplication on the inactive chromosome)
Seems like one has to search for gene changes combines with duplications and be lucky to find a woman who has them on her active X chromosome.



Jun. 04 2012 05:02 PM

Excellent Episode!
Some Colorful Music by OK Go:
"WTF" - watch video.
"Before the Earth Was Round" - listen with eyes closed.

Jun. 04 2012 12:59 PM

Christine on May. 27 2012 08:44 PM you asked about the music around 5:41...I too was so very taken with this beautiful song. Well, my attorney at work has a Yale educated opera singer for a brother. He lives in NYC and we began working on the mystery after I struck out with two other music major types...The answer: Vivaldi - "Nulla in mundo pax sincera!" I wish they would post all the music snippets they use!

Jun. 03 2012 05:53 PM

Great show but you neglected a very important piece of the machinery that allows us to perceive color: the brain. I think that this is the deeper answer to why the ancient texts don't mention blue. Yes, manufactured and naturally occurring blues were rare and yes they lacked a word for it, but they also did not perceive it because there was no part of their brain sensitized to it. This was also true for the little girl, and for the monkeys, until they had time to practice. For the brain to develop a spot that lights up when blue hits your eyes you must see blue often. This is also true for musical notes. It is why the painter could see more colors, he had practice. You notice all these things but never really put them together. The ancients didn't just lack a word for blue, they literally lacked a physical circuit of neurons in their brain that would allow them to experience it as something distinct.

Jun. 03 2012 04:55 PM
Bill McKenney from Lexington, MA

The little girl at the end of the show didn't see the blue sky because to a little kid, the sky isn't blue - it's white. It only becomes blue after her lens turns slightly yellow from exposure to sun light. The yellowing of the lens filters the yellow out of the spectrum and leaves blue. As we get older, the yellowing increases and the sky looks even deeper blue. Because we all see the world through unique lenses, color is a personal experience.

Jun. 03 2012 08:16 AM
Molly from Boulder

There was quick mention of colors we can only dream of. I have had some dreams where, when I woke up, I thought that I had seen colors beyond the visible spectrum. Curious how THAT works. Loved and learned as always with these guys. I want to be Jad and Robert when I grow up. But in the meantime, I would love the music credits. I promise to buy the songs, as I add them to my (newly created) color song playlist. Anyone have the list?

Jun. 01 2012 06:35 PM
Mariana from Buenos Aires, Argentina

Loved the podcast. Like most listeners, the sky will never look the same again to me. The last bit of the talk reminded me very much of Lera boroditsky's lecture on how language shapes our thoughts.
In that talk. She explains how the amount of colors we name affects our ability to perceive them. Apparently in russian there are 5 different names for green and that raises thheir ability to perceive differences tht speakers of other languages do not see. Got me thinking that maybe our generation can perceive more colors than two generations ago as we are exposed to more colors (just choosing a paint for your room exposes us to tons of variety).

May. 31 2012 07:34 PM
Liam from Kabul, Afghanistan

I have a small issue with the part of the show about the gamboge resin. As a security contractor working in Afghanistan who handles small arms on a daily basis, I'm pretty sure that any medium or large caliber round would shatter a piece of bamboo into a thousand pieces. It seems a lot more likely that the resin harvesters put some old lead bullets into the resin to make it heavier at sale.

May. 31 2012 11:51 AM
Odm from Toronto

Robin eggs are blue, and very much so.

May. 30 2012 07:38 PM

The third section was so fascinating!

You know where this breaks down? The f@#$ing sky!

May. 30 2012 06:38 PM
Nathan from Edmonton

The podcast on colour was great. I thought that the podcast however should have made it clear that most colourblind people are not dichromats but rather anomalous trichromats like myself (we still have three kinds of cones but one is a little wonky).
I found the discussion of learning to see colours as well as the link between words and colours very interesting.

I once owned a pair of fluorescent yellow sunglasses (hey it was the 80s). As far as I could see the frames were all the same colour. After owning them for several months someone mentioned to me about the two colours on my glasses. I found out that the arms of the glasses were actually fluorescent green, from that time forward I could easily see the difference between the green and the yellow on the glasses.

My three colourblind brothers and I have shared many similar stories where we can't differentiate two colours until someone tells us which one is which.

May. 30 2012 03:35 PM
MT from Greece

After listening to this podcast I decided to look into Homer's writings a little more closely. The declaration that the color blue was never used doesn't seem to be correct. Homer often used the word "κυανος" to describe everything from the snakes drawn on the armor of Agamemnon to Poseidon's hair. This is the root word of "cyan". In ancient Greek, κυανος was used to describe dark blue rather than the green-blue that cyan refers to in English. In the newest translations of the Iliad, into modern Greek, "κυανος" is translated to dark blue or "μαυρογαλαζιο".

May. 30 2012 09:53 AM
Gus Savoie from Saint John, New Brunswick

The last argument of lack of language to explain why the ancients seem to have a lack of colour range is pretty damn weak.

Even if we can "prove" that humans had the physical capability for trichromatic vision a zillion years ago - that doesn't mean that we'd established the neural software to perceive them discreetly. You totally could have tied this into the sequence about the colour-blind chimps - for whom the exact same action was demonstrated.

If anything the language argument is a bit more like the cart before the horse.

Thank you for posting my rant. Enjoyed the crap out of the show otherwise and no, I did not read any of the previous comments that may have already covered this ground before posting. :-)

May. 29 2012 02:54 PM
Sarah B.

just have to say all the songs you guys featured were awesome but hte best colour song by far and forver is JImmy Hendrix's Bold as Love. Ch-ch-check it out

May. 29 2012 11:53 AM
Bryan Reed

That was a really cool episode. I think there's something that should have been pointed out, though: Those shrimps wouldn't just see finer gradations of color than we do. They'd actually see extra DIMENSIONS of color.

So humans can see three dimensions of color, which we can call hue, saturation, and brightness. Which roughly translate to (1) which color in the rainbow looks most like the color (though you get into trouble with purple!), (2) how much the color looks like its ideal hue rather than a washed-out mix of the ideal hue and white, and (3) how much total light there is. Well, you could argue that changing the brightness just gives you the same color but more of it, so we're left with a two-dimensional color space.

But the dog can't see that. It would presumably just see brightness and some mix of hue and saturation. So its color space is impoverished in a way that's more than just range and precision of gradation; it's a difference in dimension.

If you've ever been lucky enough to see an argon-ion laser that's tuned to 488 nm, you've seen an intense, beautiful, pure cyan color. Cyan light is never that saturated in nature, so your eye is seeing a really unusual pure spectrum, and your brain interprets that as something pretty special. Show that to a dog, and it would presumably just see something that's bright and somewhat bluish and wouldn't detect the fact that it's an unusually saturated color at all. The thing that makes that color unusual is something that the dog's eye can't detect.

Now consider the deficiency in our vision. To make "yellow" light, our computer monitors mix red and green light. That's because the manufacturers know that our eyes can't tell the difference between a mix of red and green and a mix of yellow with a little bit of white. But that's just an accident of the design of our particular eyes. There's no physical reason why a mix of 630 nm light and 530 nm light should look like 580 nm light, but our eyes can't tell the difference, so our monitor manufacturers can get away with it.

But it wouldn't work on those shrimp. To them (again, presumably; it's hard to look into the mind of a shrimp!), the "yellow" light that we see on our monitors wouldn't look yellow at all. It would look like a mix of red and green. It would look like some color that we can't even imagine. The difference between (red + green) and (yellow + white) is this completely-invisible-to-us extra dimension of color. An animal with 15 pigments is in principle capable of seeing 12 independent dimensions of color that are similarly invisible to us. This goes way beyond being able to see fine grades of green-blue. It's of a different order entirely.

And in terms of the physics of the spectrum itself, it goes even beyond that--in principle, there are an infinite number of dimensions of color, of which we can see three. Or two, depending on how you think of it.

I think I'd like to see a "Short" podcast that follows up on this topic!

May. 29 2012 11:03 AM
Christopher Murray from Ireland

That the swatches all looked the same could be dependent on the nature of the light illuminating them. In the park the particular spectrum (colour temperature) of daylight that day could have made distinguishing them easier. I had to get a new car door, and the body shop did a good job of matching the colour in most conditions, but under some artificial lights, particularly sodium street lights, the door was distinctly different.
On the subject of distinguishing blue from green, I find it perfectly plausible that the two could be indistinguishable. Remember the classic case of "L" and "R" sounds to Japanese native speakers. Japanese only has one of them, so the brains of Japanese speakers lose the ability to tell them apart.
Finally, I was disappointed you didn't use the "Flowers are red, young man, and green leaves are green" song to illustrate the show, such as Alma not having blue imposed on her as the colour of the sky.

May. 28 2012 04:07 PM

In reference to:

"tekeleth" does not mean "blue" at every instance of its use across history in Hebrew cultures. Likewise, even that website acknowledges that a precise word for "blue" does not appear at all in the new testament (After consulting my analytic lexicon on "huakinthinos" I'm less than convinced it refers to a standard of blue we would accept.)

The Bible's been around a while. There are reputable theologians and hermeneutical studies worth referencing all over the internet, yet somehow modern Christians prefer any website with a conveniently short and flawed analysis of some biblical passages in English to support their bias.

May. 28 2012 03:58 PM

Why couldn't that little girl see the "blue" in the sky?

A simpler explanation.

If you stare up at a bright blue sky you have to squint -- almost painfully so. This is just like looking at something very bright white. Perhaps she correlated "white" with eye squinting bright. And what she perceived was the overwhelming brightness, not the color.

May. 28 2012 12:50 AM

What is the that piece at 5:41? I think it is Vivaldi, but I can't remember for the life of me. ~

May. 27 2012 08:44 PM
Chava from Jerusalem

blue in the bible:

May. 27 2012 03:55 PM

Your source material is flawed. If you are interested in accuracy I recommend using sources that actually contain commentary on the original language from a biblical scholar. You may want to start with 'The Five Books of Moses' by Robert Alter. In reference to Numbers 15:38 for example there is approximately a paragraph of commentary regarding the 'twist' and the word 'blue' is definitively not used.

May. 27 2012 04:17 AM
Bruce Alley

Pink is not a natural color. There is no pink/magenta photon and the perception of pink is an integration of red and blue photons in the brain.

You purport one of the women interviewed to be a 4-coner, and as evidence she identified pink in a clouded sky that the male interviewer apparently did not see. However, pink is something that most color seeing males can identified.

Because of limited sample size and lack of control for variation in color perception, your 'blind test' suggests a false positive result and must be dismissed as an example of confirmation bias.

May. 26 2012 11:01 PM
Laura from Milan

Wonderful podcast, thank you. As for the theory that colors are not named until they're used in objects, it's an interesting idea, but I don't believe that could apply for the ancient Greeks. There are pieces of jewelry made from cobalt blue glass from that era, and after the sky, what could be more truly blue to us than cobalt?

May. 26 2012 05:02 PM

Listening to this episode, I was reminded of the book "The Giver" by Lois Lowry. In it all people have been bred to be colorblind as part of an effort to eliminate differences among people. The main character is at one point perplexed that an apple looks "different" in a way he can't explain...later he learns that he possesses intermittent color vision.

May. 26 2012 12:22 PM

I don't know for sure, but couldn't you find more of these 4 coned people by asking people if the sky they see in reality is never quite the same color as the sky seen in movies. Since film, and now digital chips, use the three color spectrum, I'd imagine it would never be able to capture the colors that a 4 coned person would be able to see because it always goes through essentially a 3 coned filter. Hence if you throw the question out there, "Why is the sky always a different color in movies and photos?" and people bite, then you could find more of these elusive unicorns of the color spectrum world.

p.s. incredible episode. I love you guys.

May. 26 2012 08:04 AM

@ iwr:

Light can be thought of as having particle-like properties. Light interacts with matter much in the same way that rain hits some surface. Individual droplets of water may bounce or be absorbed and splash on your umbrella, but you're kept dry underneath. A shadow is like a 'dry' area, except that the raindrops, in the case of light are photons traveling at 3x10^8 m/s. A shadow, in some sense is what you *don't* see.

May. 25 2012 10:58 PM
Dave from South Carolina

Not recognising colors until they are named makes sense. This would be analogous to being tone deaf until someone told you sounds represented individual notes. You may hear the sounds and be able to tell there is some difference when the frequencies were far apart and strung together in a song but played one at a time and spaced closely in frequency, it may be difficult for many people to distinguish or name the note being played. Similarly, playing the same note with different wave shapes (piano vs flute) may be difficult to match as the same frequency. Colors could have the same implications.

May. 25 2012 07:34 PM
Sandy Marsh from Washington, DC

Who is this woman that can see various colors?...if that's even possible. Anyway, it's a good point--what is within us and what is outside of us?

May. 25 2012 06:42 PM

Loved the podcast!!

What I think was left unanswered is the question of are objects actually colored? Why does a rose appear red? Is there some property within the rose that makes it appear that color? Could light ever make green grass appear red? We do not see grass as red, why?

May. 25 2012 04:52 PM
hari from bangalore

I will never see the blue again in similar light.

May. 25 2012 03:21 PM
Claude Crépeau from Montreal, Quebec

I really like this program. It is a great way to introduce colors to people. However, one thing you fail to capture is the fact that the rainbow DOES NOT contain all the colors we see. For example, "brown" is a color that is not found in the rainbow (!!!) that we see every day. The colors of the rainbow is a subset of all the colors that our eyes see. If an animal's eye has more types of cones than humans, they will distinguish colors that we think are identical... There are several combinations of red-green-blue that produce the same color in our minds.

May. 25 2012 03:14 PM
Henry from SF Bay Area

I am huge fan and I have listened to all of your excellent shows. I was surprised to notice a major logical flaw in the podcast at about 28:30 into the show. It was about if you could see color in a world when people did not see color. Basically everything would be black or white ONLY because people could only see black or white. The problem with that is some of what most people would see as black would be deep purple or dark red or dark blue. Color blind people would use these colored dyes etc as black because that is all they would see but the color enabled person would see it for the color that it is. The color blind people would be using their black paint which was actually colored thinking it was black. Similarly a shade of gray might actually be a light pink. They would never know but the person who could see colors would see these colors.

Just like normal people would use shades of green that look exactly alike to them indiscriminately. While women with the extra color perception would see them as different colors. For example different paint companies would produce "identical" green wall paint using different formulas which normal people would see as the same but the enhanced preceptors would say that they are different colors.

The natural world would be filled with these extra colors but also the artificial would be as well. Just because normal people can't see them does not mean that these colors are not all around us or that we don't produce then inadvertently.

Also, an "red" apple gives off a set of wavelengths of light but the perception of redness does not belong to the apple or these wavelengths. That redness is only inside the head of a perceiver. It is as arbitrary as the name "apple". Our consciousness assigns a sensation to the stimulus that the eye sends us. There is no red in the electrical impulses that enter our brain. These impulses are interpreted as red.

It is about perception and the communication of perception. I am red-green color blind and it almost has no effect on my life. I can agree with people about when something is red or green but every now and then I am reminded that I don't see the world the same way as other people do.

May. 25 2012 02:12 AM

fun little page on perception - individual and collective
3 videos of 3 colors you can guess which color each video is describing.

May. 25 2012 12:58 AM
Cynthia Johnson from Colorado

Contrary to what is claimed in the program blue is used often in the Bible. It is specified in the Mosaic law that a blue thread be worn above the fringed edge of the Isrealite's skirts. This requirement can be found at Numbers 15:38. “Speak to the sons of Israel, and you must say to them that they must make for themselves fringed edges upon the skirts of their garments throughout their generations, and they must put a blue string above the fringed edge of the skirt,"
It is also mentioned in Revelation 9:17 where it decorates the breastplates of a heavenly calvary.
There are several other instances mostly pertaining to blue thread or cloth.
This comes from the 'New World Translation' published by the Watchtower Society. Perhaps the person who claimed its absence from the Bible was only aquainted with versions that translated the word differently from the original Hebrew and Greek text although I can hardly see why one of the basic requirements that helped distinguish the Isrealites from the people of the nations would be mistaken.

May. 24 2012 07:15 PM
apollyg from tomorden

It is somehow comforting that the normal processes of life- those that are to do with peaceful occupation continue irrespective of war. I was surprised by your outrage at the paint man- and I think he was surprised as well.

May. 24 2012 03:02 PM
J. Overby from Portland, OR

Awesome episode. I like how the final piece relates to 'The Perfect Yellow.' Paying attention can create perception. It's very similar to how perfect pitch works (awareness of a phenomenon as part of a system builds more concrete conceptual boundaries) or how a cook might develop his palate. Keep em coming! Thanks!

May. 24 2012 12:37 PM
MW from Baltimore, MD

Using/equating frequency of sound with frequency of light to explore the appearance of a rainbow to different creatures is really one of the coolest things I've heard. 'Red' with a lower frequency than 'blue' should *sound* lower than blue, which is exactly what we hear. Brilliant! I imagine individuals with synesthesia or who are musicians listening to this harmony probably would feel like they could see different or richer colors.

Also, the last segment about culturally constructed terms for different colors and the confusion over their existence in a physical sense is neatly cleaned up by making the distinction between sensing and perception!

The best episode you guys have done for a while, imo.

May. 24 2012 06:27 AM
A. Torp

There may be a bit more to the story about Newton's spectral colors and why indigo is there. I've seen it suggested that Newton was simply naming the colors differently than we usually do today. Looking at the way Newton divides up his spectrum, what he refers to as blue seems to correspond better to what we would call cyan, while his indigo is what we would call blue. This would make his spectral colors in modern terms red, orange, yellow, green, cyan, blue and violet. If you look at the spectrum, this division does seem to make some sense. It is still true that Newton wanted to correlate the colors to other sets of seven, such as the musical notes and planets.

Though, of course, "Roy G. Biv" does roll of the tongue a bit more easily than "Roy G. Cbv".

May. 24 2012 05:13 AM

Something questioned but not answered in the podcast: Why did Newton add "indigo" to his visible colour spectrum? He did so because, as a numerologist, "seven" was a very special number. He believed there was a connection between colours, the number of openings in the human head, the musical notes, the known objects in the solar system, and the days of the week, etc.

May. 23 2012 09:37 PM
Andreea Epure from london uk

Tengo ganas de vivir- camilo sesto- min 46

May. 23 2012 08:36 PM
Elizabeth from Buffalo, NY

My mother and I see some colors completely differently. We always argue about what is blue and what is green and about all the colors in between. I've always found this fascinating and I wonder if this has something to do with our cones?

May. 23 2012 01:41 PM
Yellowlab from Urth

@tiaelena Radiolab did explore synesthesia in the "Limits" episode but I think it was more about numbers than colors.

May. 23 2012 12:40 PM

For Ben and everyone else seeking a list of artists featured in this episode, check it out:

May. 23 2012 11:47 AM

Has anyone noticed that the movie 300 doesn't have any blue in it? greeks must be color-blind. I wonder if Frank Miller knew of Gladstone's theories before creating the comic?

May. 23 2012 11:11 AM

What is the likelihood of a successful eye transplant? I want to see if the human brain can handle 16 color receptors.

May. 23 2012 10:44 AM
Albert from 18466

Blue: The ultimate story of hiding in plain sight!
Just imagine the researcher that did the test with green and blue squares was dressed completely in blue with blue cover up make up all over his exposed skin. What would the tribes people have seen?

May. 23 2012 08:31 AM

Does anyone know where we can get a list of the tracks featured on this episode? I have looked everywhere!

May. 23 2012 12:48 AM
dbraveheart from nyc

Where can I find all these songs???

May. 22 2012 11:25 PM

@Ian from NYC
In my Bible the word tekhelet is only ever translated as blue, what do you mean it is also used for yellow and cyan (which is just pedantic for "a type of blue"). Where is it translated differently?

Wikipedia has a nice article on it at Tekhelet.

May. 22 2012 11:19 PM

I was really hoping that this story would explore grapheme–color synesthesia - where people see numbers and letters in colors. Seems like this would be just the type of topic that Radiolab would love.

May. 22 2012 10:25 PM
Cowan Weirdo

Love the show but sometimes frustrated by the sloppy process. Why would Tim Howard duck around the tree and record the answer just prior to asking Susan Hogan the question? Would it be so hard to do this ahead of time, so we don't have the uneasy feeling that maybe Susan did hear him?

Having listened to almost every episode of Radiolab, I notice a general lack of scrutiny, as if the narrative is so fragile (and in some cases - I can't help but think - the science as applied is so specious) that scrutiny might unravel it completely.

I know Radiolab is a light survey of modern science, interspersed with human-interest vignettes, but people, myself included, respect and apply the information learned. Only wish I didn't feel so ambivalent about doing so.

May. 22 2012 10:16 PM
Wendy Mok Schroeder from Los Angeles, CA

Victoria Finley's book is a good read. Very interesting stuff.
I do feel bad that I've been enjoying the super color sensitive mantis shrimps as food. I didn't realize they are so talented when it comes to seeing colors. They taste really good deep fried with peppered salt--a really popular yummy dish in Hong Kong.

May. 22 2012 09:03 PM

How exactly are they exploiting musicians?

May. 22 2012 08:14 PM
adam g

does anyone know the name of the classical, instrumental piece that comes on at around 35 minutes in, and plays up until 'a lighter shade of pale' starts?
If possible, would you happen to know who the performer is?
I've been going crazy for the last hour trying to figure it out!!!

May. 22 2012 07:46 PM
Sarah Siddell from Berkeley CA

I love your show. I've listened for years and recommended it to many people. So it was very sad for me today to have to have to stop listening to the program on Color because that screechy choral music was driving me up the wall. I simply could not stand it! Interspersed with all these different voices reading ads and credits, the crazy music made my head feel like it was about to explode. I hate to miss the other (probably interesting) information contained in the Color show, but I simply can't bear to hear all that stuff.

I don't know whose idea all this jazz is, but let me say that Radiolab was simply great as it was before the innovations of music and listener voices. It needed no embellishment and was marvelously entertaining on the basis of the stories you did. I wish I could listen to the pieces you do without all the rest.

May. 22 2012 06:48 PM

way too exploit independent bands

May. 22 2012 06:13 PM
Ian from NYC

"You state that the philologist claims that blue does not appear in the ancient hebrew bible. How then does Exodus 25:4 translate to mention blue thread?"

As with all biblical verses, the word blue is a translation of a Hebrew word תכלת (techeleth) which is translated to everything form cyan to yellow. Not just blue.

May. 22 2012 04:39 PM

If you really want to be convinced that the colors we see are an illusion, read about how the new 3D movie technology works. Each eye is sent a different set of three primary colors, but they are mixed in a way to give the perception of identical colors in each eye (but a different view of the image). Read about Wavelength Multiplex Imaging.

May. 22 2012 04:38 PM
Tim from Radiolab

Josh, Guy also mentioned that in the case of Biblical Hebrew, the word that would later come to mean blue actually meant black. Apparently this is the case in many languages, that "blue" comes from the word for black. Or, less often, from the word for green.

May. 22 2012 03:28 PM

Josh: In his research, Geiger found no occurrences of blue in the Hebrew bible — but there is some debate about this, as with pretty much all things biblical. The word that appears in the Exodus passage you mention is tekeleth. While it seems to be generally defined as violet, it does appear in some translations as blue.

May. 22 2012 01:56 PM
Michele from Brooklyn

Thinking constantly about color is part of my job, and I loved this collection of stories! Something that has never been adequately explained to me: scientifically, color is linear, with red (and infrared) on one end of the wavelength spectrum and violet (and ultraviolet) on the other. So when we're talking about mixing color, why do we talk about the color wheel, and think of color as circular?

May. 22 2012 01:56 PM

You state that the philologist claims that blue does not appear in the ancient hebrew bible. How then does Exodus 25:4 translate to mention blue thread?

May. 22 2012 11:38 AM
lr from in

i think darkmater is in everything and is what holds it together when it is releasted it is so fast that it causes light heat gravit and life.drakness is whats faster then light

May. 22 2012 10:43 AM
Jesse D'Angelo

For people who want their color fix I recommend checking out The Color Spectrum by The Dear Hunter. Here is a link to the Wikipedia article about it ( Each of the nine EPs has for songs total covering black, red, orange, yellow, green, blue, indigo, violet, and white. The music covers a plethora of genres so odds are there is something for everyone. Either way it is a cool project all about colors.

May. 22 2012 10:08 AM
lwr from in

if what you see is the reflection then what are shadows

May. 22 2012 10:00 AM

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