Many people dream in color. Some also read and hear in color. In people with synesthesia, different senses blend in a variety of ways—one person might see the numeral four as bright yellow, and another might taste cucumbers when she hears words beginning with the letter “F.” And because synesthetes are aware of connections among parts of the brain that to most people seem distinct, they may help scientists map the mind's higher cognitive functions.
Julia Simner, a linguistic psychologist at the University of Edinburgh, is among a new crop of researchers exploring how conceptual thinking (not simply physical stimuli) may evoke colors and flavors in synesthetes. By inducing a “tip of the tongue” state—in which a known expression eludes immediate recall—in synesthetes who taste words, Simner discovered that the meanings of words can produce the same flavors as their sound or written shape. For instance, trying to remember the term “castanet” caused one woman to taste tuna, the same flavor triggered when she heard the word. Through this type of “word tasting,” Simner is exploring the potential relation between conceptual thought and perceptual experience.