Ever taste a shape, or smell a color?ATLANTA, Georgia (CNN) -- Imagine a world in which the senses fuse together; where sounds are seen and words and aromas have color; where the number 10 can be smelt, and fuchsia has flavor. That's the world of synesthesia -- loosely defined as a difficulty in distinguishing between different sensory inputs.
Synesthesia means "joined sensation," and is an automatic physical experience in which one sense triggers off an additional perception in a different sense or senses. For example, a synestheste not only sees the color red, but might "smell" it, too.
Neurologist Richard Cytowic, author of "The Man who Tasted Shapes," said a synestheste's experience forms the building blocks of perception. "They get a sampling of perception at an earlier stage before it becomes separated -- before, that was a sound, this is a color, a texture..." he explained.
The phenomenon varies in impact. It could be a disorder in some, and a perceptual curiosity in others. It is rare however, occurring in roughly one in 25,000 individuals.
But people who experience the phenomenon, the ringing of a doorbell could resemble a series of triangles, or a dog bark could seem like a circle with dots around it. For a more tangible peek into this enigma, synesthestes recommend Walt Disney's "Fantasia," an animated film that attempts to visualize music.
Artist Carol Steen, who is part of the tiny world of synesthestes, says she possesses a "wonderful gift." The shapes and colors she experiences through music and acupuncture, she said, inspire her paintings and sculptures. "I use the colors I see. I use the shapes that I see," she says. "It's like an additional form of consciousness."
Cytowic attempts to provide some insight into the enigma using a black and white placard printed with the word "weary." That same placard, he said, would appear flush with different colors for a synestheste. "For us, the touch, taste and smell, they are all separate," he said. "But for synesthestes, it is not."
For Cytowic, who has spent more than a decade studying synesthesia, it is more than just an unusual phenomenon. He thinks of synesthestes as "cognitive fossils," and believes a search to understand the condition will eventually lead to a new model of the mind.