Synesthesia is a condition that was originally described sometime in the 1880's, by whom I don't recall, and it's caused by a failure of the cingulate gyrus to de-wire wiring in your brain that's really tight when you're a fetus.
In English, the cingulate gyrus is a part of your brain that runs along the sides of your head, just above your ear. It does all sorts of things, including regulate the perception of various sensory input. In human development, all the different types of sensory input are wired together, but as you mature in utero, that wiring spaces itself out. The result is that you have five senses, and they don't overlap.
Synesthetes experience the world with perceptual overlap, is the best way I can describe it. They taste color, they smell sound, or they see sound, or they attribute personalities to letters and numbers. About one in twenty people is a synesthete according to current reckoning; I suspect the actual proportion of synesthetes is much higher, based partly on what happened the other day.
So I'm listening to NPR. And this woman puts on a techno record, and says, "Now, this is obviously a dark gray background with light gray and white dots." And as I'm chopping poblano peppers, I'm thinking, "Bullshit. This is obviously blue with yellow and silver streaks."
I stopped chopping. I considered what I'd just thought. And I ran to the CD player.
Bach: intricate uncolored geometry. Beethoven: woodgrain in sweeping pastel colors. "Rhapsody in Blue": the clarinet slide is obviously a bright medium-blue, and it tastes like blue besides.
Then I remembered what happened every time Mom played ragtime music as she was cleaning, when I was a kid. All I saw was somewhat chaotic flashes of color, moving with mathematical precision, across my internal film screen. It became so distracting that I began working consciously to ignore it. Later, in college, I would practice piano and build up this gorgeous, fragile matrix of colorless, clear geometric shapes that one mistake would make come crashing down (I hated practicing piano).
I emailed Beloved Sister about this, and her response was, "WOAH. You mean not everybody does this? And there's a name for it?" Turns out she does it too: the number nine tastes like cranberry, while the number seven tastes like tin. Neither she nor I have total saturation (as she puts it); some music evokes no visual response in me at all (thank God; constant visual distraction would drive me bonkers) and some numbers and letters have no taste or smell for her.
Eight, for me, is a fluffy purplish-blue, five is yellow, and seven has the personality of the Tin Man from the Wizard of OZ. The numeral one doesn't get along with anybody. All of which was more interesting still after I talked to Friend Pens the Lotion Slut last night.
She said, "Well, I don't see colors with music, but I do know that certain numbers and letters have personalities." And, "You mean not everybody does this? And there's a name for it?"
Three people with at least partial synesthesia in twenty-four hours. I know the proportion of people who experience the world this way *must* be higher. We just haven't heard about it, since the study of synesthesia fell out of fashion in the 1920's and didn't re-emerge until we got good functional MRI capabilities in the 1990's.
It explains why I love Philip Glass and hate techno and ragtime. It explains why Bach relaxes me and Mahler seems so avant-garde. It also explains why the shouty Katy Perry is a nasty burnt-orange voice, while the dude who sings for The Magnetic Fields is dark charcoal grey with fuzzy edges. It's simply *there*: the film that plays in my head is nothing I can change, and it's the same every time I listen to a particular piece of music. I'm lucky enough not to be one of those people who see the music across their field of vision; I don't have to walk through colored flashes of light when I'm crossing the lobby at work, for instance.
It also explains why so much of my wardrobe is an odd shade of yellow-green: it makes me smell yarrow, one of my favorite Texas-In-Springtime smells, every time I see it.
My sister has the additional gift of being able to switch her visual perception from three dimensions to two at will. It's such a natural part of her being that she can't explain it.
Every day I am amazed at how normal abnormalities are when you really look around. When a friend of mine told me he'd only had synesthesia when he was altered, I was a little shocked. It seems like everybody ought to be able to do this, you know?
And this, friends, is why I love neuro nursing.