Synesthesia is the blending of senses: where a stimulus for one sense such as sight or hearing, leads to the involuntary activation of another such as smell or touch. (For cognitive pathways in general). It comes in many forms, and the cause is still being debated. The main theory is that we are all born with synesthesia, and eventually lose the connective pathways until we only experience a stimulus in one particular area of the brain. People who experience these later in life are called synesthetes.
I've always been fascinated by this condition. I would think it would add another dimension to the world, and allow for creativity like it did for Kandinsky's art, or Duke Ellington's jazz (both said to have been synesthetes).
There are many different kinds: Grapheme-Color is the connection of numbers and letters to colors, and is the most common. Sound - Color is common as well, and is when people see colors when they hear sounds or music. All types of synesthesia are highly personal; each experiences their synesthesia their own way. For example, the letter P might be Blue to one person, or Purple to another, and it disturbs them to think of it any differently. (Which makes reading colored print difficult.) A girl in my gym class said her favorite number was something like 245 because of the color it was). In sound - color synesthetes, the sound which produces a certain color may vary. Some experience a color for a specific pitch (such as a B flat) or for a certain key of music ("C minor is dark green!") or for a specific instrument (One man describes french horns as an awful color, so refuses to listen to symphonies that feature that instrument.) Other even stranger types include personification (ordered sequences have personalities), and lexical gustatory (words to taste) synesthesia.
