Have you ever heard orange? Or tasted triangular? Those are a couple of examples of a psychological phenomenon called synesthesia. That’s when one form of perception produces another. For example, sounds might make a synesthete see colors as well. The word synesthesia comes from the Greek “syn” for together and “aisthesis,” to perceive. It means joined perceptions.
Estimates range from 1 in 200 all the way down to 1 in 100,000 people having the ability. But there are thought to be many synesthetes who don’t realize it. They have no reason to know that other people don’t share their way of perceiving the world. Especially when there are so many figures of speech that seem to imply that it’s a universal condition. Why else would we have “round numbers,” “cold logic” or “bright ideas?”
Wikipedia, the open-content encyclopedia project, defines synesthesia as a neurological mixing of the senses. That is, the five senses, sight, hearing, touch, smell and taste, get selectively blended in the brain. Each person is different. One might hear colors while others see sounds or taste shapes.
The effect is consistent for each person. So, if they see the letter “a” as red, it is always red. A linguistics researcher, Karen Chenausky, who has synesthesia, says that she sees the word “linguistics” as a grayish-purple-blue. Where we see black ink on white paper, she sees it in color.
The most common synesthesia has colors linked to other sensations. There will be specific colors for printed letters or numbers, for the sound of words or music, or for smells or tastes. Next most common is to experience tastes or smells when the other senses are stimulated.
More women than men are synesthetes. Synesthetes are more likely to be left-handed than the general population. Sometimes they have a poor sense of direction, or trouble telling left from right. They are normal mentally and intellectually, though some have trouble with mathematics. Synesthesia tends to run in families. Famous synesthetes include the composer Franz Liszt and the physicist Richard Feynman.
Synesthesia is thought to result from overlaps or crossed connections between parts of the brain that process the various perceptions. Some researchers believe that infants have such overlapping senses, which are segregated as they mature. The degree of segregation would simply be reduced in synesthetes.
Now, if you’ll excuse me, the telephone is vanilla.