Synesthesia

My first introduction to Synesthesia was a Scientific American article I read at Barnes and Noble a few years ago. Basically, it's a fairly common (and non-harmful) brain disorder(?) where the language part of your brain and the parts that control the senses are interconnected in a way that they are not supposed to be. Because of this, people who have synesthesia hear colors, see sounds, feel tastes, etc. They don't imagine them, they see them. Also letters and numbers are usually color coded for them. here's a great quote from The Mind of a Mnemonist


"there are people who seem to have many voices, whose voice seems to be an entire composition, a bouquet. .. Eisenstein had just such a voice: listening to him, it was as though a flame with fibers protruding from it was advancing right towards me. I got so interested in the voice, I couldn't follow what he was saying . . . to this day I can't escape from seeing colors when I hear sounds. What first strikes me is the color of someone's voice. Then it fades off... for it does not interfere. If, say, a person says something., I see the word; but should another person's voice break in, blurs appear. These creep into syllables of the word and I can't make out what is being said"

-http://www.amazon.com/exec/obidos/tg/detail/-/0674576225/ref=ase_cherrymagic/104-1924824-7664740?v=glance&s=books