This is a topy at a science cafe in Manchester. A nice topic for a meeting in Berne – the problem is to find someone to talk about it.
When Senses Intersect
The neurologist Richard Cytowic discusses what synaesthesia can teach us about ordinary perception, creativity and Vladimir Nabokov
By Richard Cytowic from Scientific American
Dr. Richard Cytowic is one of the leading researchers of synaesthesia, a condition in which two normally separated sensations – such as sight and sound, or touch and taste – occur at the same time. As a result, a synaesthetic person might experience the taste of a dish on her fingertips, or be convinced that the letter X is a vibrant turquoise. Mind Matters editor Jonah Lehrer chats with Cytowic about his new book, Wednesday is Indigo Blue, which he co-wrote with David Eagleman.
LEHRER: What first got you interested in synaesthesia?
CYTOWIC: It was an accident. I like etymology and so knew the word, whereas my colleagues back in 1979 had never heard of synaesthesia. In fact, they refused to believe it could be real, and warned that looking into such “weird” and “New Age” nonsense would ruin my career. Their denial was the typical reaction of orthodoxy to something it can’t explain.
It is said that chance favors the prepared mind, so I guess I was ready when a dinner host apologized that there weren’t “enough points on the chicken.” For Michael Watson, who I later wrote about as “The Man Who Tasted Shapes,” flavor was more than a mouthful. Taste was also a touch sensation felt on his face and in his hands. “With an intense flavor,” he explained, “a feeling sweeps down my arm and I feel weight, shape, texture, and temperature as if I’m actually grasping something.”
Fortunately, I could use university resources to quietly study Michael in depth and write papers. What interested me most was pondering an experience that “wasn’t supposed to be.”
LEHRER: How has our scientific understanding of synaesthesia changed in recent years?
CYTOWIC: It has to do with possibilities of how the senses couple in the brain. My first idea that the emotional brain served as the link gave way, based on observations in neonatal synaesthesia, to the possibility of faulty pruning. That is, the gene in synaesthesia might fail to prune the extra synapses that are normally made in great excess in all newborns. We thought their persistence might plausibly explain why some people are synaesthetes.
Today, we know that far from being rare, synaesthesia is common––one in 23 individuals has some kind of synaesthesia, and one in 90 has colored letters and numerals. That being so, in Wednesday is Indigo Blue David Eagleman and I favor a genetically–determined imbalance between excitation and inhibition. We’ve learned that the normal brain is already highly cross–wired. We think synaesthesia occurs due to increased activity in existing wiring rather than the result of extra wiring.
LEHRER: What can synaesthetes teach us about the nature of human perception?
CYTOWIC: Far from being a mere curiosity, synaesthesia is a consciously elevated form of the perception that everyone already has. Minds that function differently are not so strange after all, and everyone can learn from them.
Synaesthesia has opened up a window onto a broad expanse of the brain and perception. Younger researchers are now active in 15 countries. Because the trait runs strongly in families, it is easy to collect DNA from a large number of synaesthetic relatives. This means that synaesthesia may be the very first perceptual condition for which science can map its gene. This inherited quirk is teaching us that cross–talk among the senses is the rule rather than the exception––we are all inward synaesthetes who are outwardly unaware of sensory couplings happening all the time.
For example, sight, sound, and movement normally map to one another so closely that even bad ventriloquists convince us that whatever moves is doing the talking. Likewise, cinema convinces us that dialogue comes from the actors’ mouths rather than the surrounding speakers. Dance is another example of cross–sensory mapping in which body rhythms imitate sound rhythms kinetically and visually. We so take these similarities for granted that we never question them the way we might doubt colored hearing.
