Synesthesia is a phenomenon in which people’s senses seem to be crossed. Some people with the condition can feel tastes or see sounds; others taste voices (think of the opposite of anesthesia, literally “no senses”). Neurologist Richard Cytowic has studied such people for more than three decades, starting with a man in the rare latter category.
“Some people are born with two or more senses hooked together,” Cytowic told an audience of around 120 people at the Library of Congress on Oct. 30. For example, for the first synesthete he studied, some flavors “were more than a mouthful.”
Synesthesia experts estimate that one in 23 people has some form of this involuntary sense-mixing. Some scientists working with infants theorize that all babies are born synesthetic but lose the trait at around three months, when their sense networks start to firm up.
In 1979, when he was a young researcher, Cytowic said, no one had heard of synesthesia, and if they had they thought it wasn’t real. But he was hooked—“it interested me to explain a subjective experience that seems impossible to prove.”
He and others eventually did prove it, through well-designed experiments and a mass of data from people who started calling and writing to describe their experiences. Now “a new generation in 15 countries” studies the trait, from its individualistic expression in behavior to its possible molecular and genetic components.
“Five groups around the world are working on analyzing for the synesthesia gene,” he said. Researchers currently think the trait is genetic (“hyperconnectivity between disparate brain systems”) but requires early exposure to over-learned groupings. For example, many synesthetes see colors or shapes related to such sequences as days of the week, calendars and other common number forms, including music. (Are you synesthetic? Take a computer-based test at http://www.synesthete.org/.)
Cytowic played two short films to help illustrate the ability. The first paired Chopin’s Valse Brillante with a moving pattern of dashes of color changing in time with the music. The second, a short film by Terri Timely seen below, cleverly captures the idea of living with many forms of synesthesia, Cytowic said. One difference, though, is that instead of the discrete objects such as cats seen in the video, synesthetes are more likely to see general shapes or colors.
Crossing sense pathways can run in families and seems to be more common in artistically creative people, Cytowic said. Examples include writers Douglas Coupland and Vladimir Nabokov (and his family); artists David Hockney and Wassily Kandinsky; musicians Olivier Messiaen, Itzak Perlman and Billy Joel; and performer Marilyn Monroe. Stevie Wonder also has a form of sound-color synesthesia. “Synesthesia is very common in blind people because you don’t need your eyes to see—you see with your brain,” Cytowic said.
Their experiences are not always positive, though. One audience member described herself as a mild sound-taste synesthete and her son a stronger one. One year at school, she said, her son found that his new teacher’s voice “brought a bad taste to his mouth” to such an extent that she had to arrange to move him to a new classroom, “and it was ridiculously difficult. Nobody believed it” when he kept saying “her voice makes me sick.”
Sometimes it’s a synesthete’s friends and family who need to close their eyes. Cytowic told of a taste-color synesthete who had to wait until his wife was out of town to eat a favorite, “very blue,” dish: baked chicken Alaska drenched in orange juice and topped with ice cream.
“Synesthetes have taught us that cross-talk is the rule, not the exception,” Cytowik said. “Minds that work differently are not that different at all, and we can learn from them.”
With David Eagleman, Cytowik co-authored Wednesday Is Indigo Blue: Discovering the Brain of Synesthesia, which was recently reviewed in Cerebrum. His lecture is part of the “Music and the Brain” series, presented by the Library of Congress and the Dana Foundation. The next event, on music and trance states, is tonight; a lecture on dangerous music takes place Friday, Nov. 6.