Taste the Rainbow.

If you've ever seen the Skittles commercial and thought to yourself. "Man, I too would like to taste rainbows," then put away the Skittles bag--what you really need is some Synesthesia.

Synesthesia is a rare, misunderstood neurological phenomenon in which one or more sensory or cognitive pathways lead to involuntary experiences in another pathway. This means synesthetes experience numbers, letters, shapes, or sounds with a diversity of color associations, personifications, or sometimes intense tastes. In the past, the phenomenon has had varying levels of interest by psychologists and neurologists. Where once it was dismissed as merely the results of too strong an imagination or too much LSD, it now finds strong acceptance by the majority of the medical community as being a real condition that affects anywhere from between 1 in 20 to 1 in 20,000 (this number is highly variable from study to study).

The article provided is a look back at classic study done by Vilayanur S. Ramachandran on grapheme color synesthesia, or the association of colors to symbols. Using a simple experiment done on college students, Ramachandran showed that the condition existed by creating a graphic filled with a random smattering of fives and twos. To a non-synesthete discerning between the numbers is pretty tough, and takes a moment to recognize the twos and then realize they make a shape. For a person with synesthesia on the other hand, the numbers appear in distinctive colors--so the process takes seconds. The results showed, as Ramachandran explained that "synestheses are not crazy, it's not a metaphor, nor is it just a memory association." According to Ramachandran 1 in 200 college students has this type of synesthesia.

At this point, we're still left wondering what's really causing the confusion. As Ramachandran suggests it may be because of gene mutations which cause gene pruning in regions of the brain adjacent to one another. In the case of these grapheme-color synesthetes, gene pruning in the fusiform gyrus (region of the brain that identifies color) may be increasing the number of cross-wiring with the adjacent area of the brain that deals with visual and graphical cues like numbers.

However, what's really interesting about Ramachandran's study are the implications to language. If cross wiring between neighboring regions of the brain can really bring together irrelevant concrete ideas (shapes, symbols, objects, etc) to abstract ones (colors, personas, sounds, etc), then synesthesia maybe the predecessor of language development in early humans. "The evidence for this is if you take two completely random nonsense shapes, one resembling an ink blot with undulating contours, and one resembling a shattered piece of glass with sharp corners, and ask 100 people, "Which one of these represents the nonsense word Bouba and which represents the nonsense words Kiki?,' 99% of them pick the amoeboid as Bouba and the jagged shape as Kiki. Presumably, this is because the jagged edges synesthetically mimic the jagged sound of 'ki-ki' This preexisting bias, however small, would have set the stage for a shared vocabulary--a lexicon."

As Ramachandran continues to explain, a kind of pre-existing synesthesia exists between the visual and hearing maps and the motor maps for motor speech sounds in and near the Broca's area. As the early hominid ancestors experimented with these connections and developed preexisting biases into common occurrence, a language could develop. This Ramachandran suggests may not just be the basis of language, but also the basis of art. For what is art but a way to connect ourselves to what is visually pleasing?

If any of this holds true, synesthetes may be the ones on the very cusp of our fine genetic cesspool.

http://www.neurologyreviews.com/jul02/nr_jul02_mindseye.html