Jim Fleming: Now, it may seem odd to create music out of color, but some people really do see blue or yellow when they hear music. Or see a color when they think of a certain number or letter.
Others actually feel the flavor of food on their fingers. They have what’s called synesthesia, a neurological condition which causes one sense to cross paths with another.
It used to be considered an extremely rare condition. Today, scientists believe synesthesia affects an estimated 4% of the population.
David Eagleman is a neurologist at the cutting edge of synesthesia research, and he's the co-author of the book “Wednesday is Indigo Blue: Discovering the Brain of Synesthesia.”Anne Strainchamps asked him to describe the condition.
Anne Strainchamps: Synesthesia can take a lot of different forms. Could you start, maybe, by giving us a sense of the range of experiences that people have?
David Eagleman: Yeah. So, there are something like 150 different recorded forms of synesthesia. It can be a mixture of the senses in any way that you can imagine. So, for example, some people will hear music, and it causes them to see colors; and other people will hear a name and it will put a taste in their mouth; other people, they'll taste something, and it will make them feel like there's something being felt on their fingertips.
Strainchamps: So, for some people, the color threeis blue, and the color fouris purple?
Eagleman: That's right. It's probably the most common form of synesthesia. Things like numbers and letters will trigger color experiences, so Wednesday will be indigo blue, and February will be yellow, and so on. And for each synesthete, of course, it's different; they have a unique palate of associations that they make.
Strainchamps: And so, that's one of the more common forms: letters or numbers that have colors, but there are others. Your co-author discovered one case of synesthesia at a dinner party?
Eagleman: That's right. The chef at... The host of the dinner party who was cooking the food, he said, Oh, the chicken is not quite ready. It's not pointy enough, and so Richard Cytowic, my co-author, said, Well, what do you mean by that? And he said, Well, you know, when I taste things, there's a certain feeling on my fingertips that I get, and I know when the chicken is ready because of the way it feels on my fingertips when I taste some of it.And that's what's happening in synesthesia, that different areas of the brain are talking with one another in ways that they don't in a normal brain.
Strainchamps: Hm. What's the most unusual case of synesthesia you've ever run across?
Eagleman: One subject that I've studied in detail is a musician. And she has extraordinarily rich synesthesia where for every pitch, for every chord, for instrument timbre, she experiences shapes and colors and textures, and she also feels as though her body is leaping or moving or sliding or falling â€” when they are different key changes, for example.
Strainchamps: This sounds like going through life on acid.
Eagleman: Well, the interesting part is that synesthetes accept the reality that's presented to them exactly the way that we all do. There's nothing interesting or unusual to them about it. For example, imagine if a color-blind person said to you, “My gosh, everywhere you look, you see colors. That must be like being on acid.”
Eagleman: You would say, “Oh, actually no, that's just what I take to be reality out there.”
Strainchamps: Uh-huh. Do scientists understand what causes synesthesia? Is there a gene that triggers mixed perceptions?
Eagleman: Well, I'm happy to say we've been making tremendous progress just in the last few years. It turns out synesthesia is heritable, and if you are in a family with synesthetes, if your parents were synesthetes, then you've got a pretty good chance of being synesthetic yourself.
So, what we've been doing is collecting up large families with synesthesia and, essentially, what you do is you look at how the synesthesia marches through the family tree, and look at what genetic changes have that same pattern. And so, we're almost there now. We're probably just a few months away from pulling the first gene for synesthesia.
Strainchamps: Well, speaking of synesthesia running in families, I noticed the afterword to your book is written by Dimitri Nabokov; that's the son of the famous Russian writer, Vladimir Nabokov, right?
Eagleman: That's right. So, it turns out that Vladimir Nabokov had synesthesia and wrote about it. You know, he had grown up reading Cyrillic, and then when he moved to the United States he was reading our alphabet, and his colors transferred. And so, he had synesthesia in both alphabets and he really appreciated it â€” loved the colors that were involved. So, it turns out Vladimir Nabokov's wife was also synesthetic, and their son Dimitri is also synesthetic.
Strainchamps: But I'm just wondering what this would be like for a writer: somebody who's trying to create beauty out of words and who's lucky enough to have this particular neurological “gift”we can call it, that gives them an added layer of sense perception that they can play with. So, I'm wondering if...
Strainchamps: ...Nabokov used his synesthesia in his writing - if it affected his writing.
Eagleman: Well, it's a very interesting question. The funny part about is, the colors that a synesthete will associate with different letters are idiosyncratic; they're just meaningful for him, and as a result, any sort of beauty that he injects into the language that way wouldn't be transmissible to other people.
Nonetheless, one can always enjoy inside jokes. And so, Nabokov, it turned out, was a lepidopterist he loved butterflies. And so, one of his favorite butterflies happened to have yellow wings and a black body, so if you look at it, it's yellow-black-yellow. Well, it just so happens that for him, the letter was yellow, and was black, so he loved the name âA-D-A, because that was yellow-black-yellow, in the same way as his favorite butterfly. So, one of his novels he entitled
Eagleman: So, that's an example of him using his synesthesia in his language. But, again, it's just an inside joke; nobody else would get it.
Strainchamps: It's an inside... Yes, just a personal joke. Wow. That's just fascinating. Now, Nabokov is just one of... There have been many famous artists, writers, and musicians who have been synesthetes. We should talk about some of the others. Didn't the Russian painter Kandinsky have, well, an especially acute case of synesthesia?
Eagleman: That's right. Kandinsky, when he would hear music, would see shapes and colors and textures. So, he would blast his phonograph and stand in front of his canvas and, essentially, paint what he was seeing. So, if you can imagine a Kandinsky, that was, for him, music.
And again, it only made sense to him exactly what that music sounded like and how it looked, but nonetheless, for the rest of us, it makes a beautiful painting. It makes very unusual, sort of, sights and shapes and textures all put together. That was his internal experience.
Strainchamps: Doesn't that make you think that you should really only look at Kandinsky's paintings if you have the music there as well? Has anyone ever exhibited them that way?
Eagleman: Well, that is a great idea. I don't know if anyone has ever exhibited it that way, but they should, certainly.
Eagleman: This is an interesting point there, because we have several idioms in our language that almost certainly were given to us by synesthetes. So when you talk about somebody having a "loud" shirt or a "sweet" personality â€” or "smooth" jazz or "sharp" cheese, things like this, those were almost certainly expressions that were introduced by synesthetes, and yet they stick in the language because they sort of make sense. We sort of get it, even though we might not be synesthetic ourselves.
Strainchamps: Do you wonder whether there's a kind of low-level synesthesia that, perhaps, we all have, or perhaps a great many people have?
Eagleman: Well, it does appear that there are certain connections across the senses that everybody seems to share, although at an unconscious level for most of us. So, for example, if I were to take a piano keyboard and hit the high note: "ding, ding, ding," and then I hit the low note: "ding, ding, ding," and I ask you which one of those is brighter, what would you say?
Strainchamps: The top one.
Eagleman: OK. And if I were to say which one is "bigger," what would you say?
Strainchamps: The bottom one.
Eagleman: Well, that's what everybody would say. And that's really weird, because all I'm doing is playing a note, and you're answering questions about luminance and size. So, what that suggests is that in everybody's brain, there are these connections across the senses where it just seems sort of natural to us that a high note would kind of be small and bright, and a low note would be big and darker.
And what that must represent is that there's cross-wiring between our hearing and our sight in all brains.
Strainchamps: Well, we should end by talking about one piece of art created by a synesthete that we can actually listen to, so, Olivier Messiaen was one of several famous composers who had "colored hearing." How did he describe it?
Eagleman: When Messiaen would compose, he would talk about, for example, a blue-orange cascade of chords. To him, that made sense, that when the music was moving in a particular direction, there was real color to it. So, he really worked to have that beauty that he saw as part of the music, and when he described it in his diary and so on, he would describe the colors as well as the music.
Strainchamps: For example, there's a piece you referred to, a 1971 Symphony, he wrote "Des canyons aux etoiles..." from the canyons to the stars, which was inspired by the red rocks of Bryce Canyon. Anybody who's ever seen Bryce or pictures of Bryce knows the rocks are this gorgeous red-orange color. Is that mostly what you hear in this piece, or are there other colors as well?
Eagleman: To Messiaen, when he wrote this music, it recaptured that color for him, that experience for him. It's not necessarily the case that any of us would have that physical color experience the way he did, but we can appreciate it adds something to us to listen to it, and know that when he heard this music, he experienced those red colors.
Fleming: Music from Messiaen's "From the canyons to the stars," inspired by the red rocks of Bryce Canyon. Anne Strainchamps talked with David Eagleman, who directs the Laboratory for Perception and Action at Baylor's College of Medicine. Eagleman's the co-author, with Richard Cytowic, of the book "Wednesday is Indigo Blue." [piano music]