Seeing Sounds and Tasting Colors

"The word synaesthesia (also spelled synæsthesia and synesthesia) is derived from the Greek syn, meaning "together" or "union", and aesthesis or aisthesis, meaning "sensation" or "to perceive". Thus, depending on who you are talking to, synaesthesia can be taken to mean "synthetic experience" or "joined sensation" or "to perceive together". And if you think this is confusing, just wait to see what's to come...

In a nutshell, synaesthesia embraces a variety of different conditions in which the stimulation of one sets of sensory inputs (say sound) is simultaneously perceived by one or more of the other senses (sight or touch, for example).

There are many different forms of synaesthesia. For our purposes here, we are primarily interested in those that pertain to color vision. One very common type is when folks associate numbers and letters of the alphabet with different colors. For example, consider the way in which a non-synaesthete would see the alphabet printed as black text on white paper as illustrated below:

Now consider the same alphabet – still presented as black text – as it might be seen by a synaesthete as illustrated below:

Note that the above is simply a representation created by the author of this paper. Every synaesthete (of this type) perceives their own color alphabet. Having said this, research on a large number of synaesthetes reveals certain trends, such as the fact that 'a' is often red, 'b; is often blue, 'c' is often yellow, and so forth.

Another interesting point is that some synaesthetes "see" the letters as being black, but "perceive" the colors as being "associated" with the letters. By comparison, other synaesthetes actually do "see/perceive" the letters as having those colors.""

"It's important to note that synaesthesia is additive; that is, it "overlays" the primary senses. Also, we should remind ourselves that there are many different types of synaesthesia. For example, when some synaesthetes hear music, they might see patterns of colors hovering about three feet in front of them. A trill of the flute may appear as a collection of purple triangles and small pink dots, for example. (It is said that if a non-synaesthete wants to get a feel for what this might be like to experience, a good start would be to watch appropriate portions of the original Fantasia movie by Walt Disney.)

So how many of us are synaesthetes? This is really difficult to pin down, because there are so many different types (listening to music can cause a tickling sensation of touch, or a perception of different smells, or ...), and different folks can be affected to lesser or greater amounts (a "feel" of a color versus actually "seeing" that color). Some estimates put synaesthetes as being roughly one in 25,000, while others say one in 2,000, and still others say as many as one in 100 may by synaesthetic."

http://www.diycalculator.com/sp-cvision.shtml#A8b

I find it interesting that some people have a natural sense for coding colors.