Why Some People See Numbers, Letters in Color

March 28 -- Even as a child, the man called "WO" knew he saw the world quite differently than his friends.

Letters, numbers and words all had distinct colors.

He knew it, because he could see it with his own eyes. To him, a page of black print didn't look black at all. It was a symphony of color. The number "2" was bright orange, "5" was green, and so forth.

His young friends, no doubt, thought he was a bit nutty, but he had one close ally. His mother understood. She knew words had colors, because she, too, could see them. They weren't the same colors her son saw, but they were colors, nonetheless.

Both WO (as he is anonymously referred to in a recent study) and his mother had a condition known as synesthesia (rhymes with anesthesia), that causes some people to hear colors, feel sounds and taste shapes. Scientists have known about synesthesia for at least 300 years, but it wasn't taken all that seriously until recently. People who claimed to hear colors were dismissed as hallucinatory, or worse.

Condition Through the Ages

A decade ago Richard E. Cytowic, a neurologist, chronicled a number of case studies in a popular book, The Man Who Tasted Shapes, and scientists realized the time was ripe to reopen the case of synesthesia. New testing procedures, and new tools that could peer inside the brain, identifying areas that are active during various conditions, could allow them to see if there really was anything to all this.

And it turns out that there is. WO really does see the number 2 as bright orange, just as thousands of others around the world see it as blue, or yellow, or whatever. It is a concept that is quite difficult for the rest of us to grasp.

"It's like trying to describe color to someone who doesn't see color," says Thomas J. Palmieri, a Vanderbilt University psychologist and lead author of a study on WO that appears the March 19 issue of the Proceedings of the National Academy of Sciences.

In his earlier research, Cytowic documented a number of startling cases, including such well-known figures as Russian novelist Valdimir Nabokov, who as a child complained to his mother that the colors of the letters on his wooden alphabet blocks were all wrong. She knew, because she also saw letters as colors, and they clearly were not the same as those on the blocks.