When you listen to music, what does it taste like? That's not a silly question. Swiss researchers are studying a young musician who consistently identifies musical intervals by the flavors they induce on her tongue.
For example, a minor second is sour. A major second is bitter. A perfect fourth is mown grass. A minor sixth is cream. An octave has no taste at all. Neuroscientists call such mixed perception synaesthesia. It's a nagging reminder that what we perceive is not just a simple processing of stimuli from one or another of our senses.
The effect can be startling, as my wife and I learned one night while sleeping with the windows open. A loud crack of thunder brought us bolt upright. Had lightning hit the house? Not quite. We had "heard" a "loud" stench. A skunk had let go outside.
The most common type of synaesthesia is the concurrence of color with a sound, taste, or scent. The musician taking part in the research at the University of Zurich experiences this. She sees C as red and F-sharp as violet. But in reporting their study in Nature, Gian Beeli, Michaela Esslen, and Lutz Jäncke note that it is her rare ability to taste musical intervals that stands out. Calling her E.S. to protect her privacy, they say this is the first such case to be reported.
The researchers say that, after extensive systematic testing, "we found that E.S.'s tone-interval identification was perfect."
The case differs from a more holistic type of sound/taste synaesthesia in which the flavor of an entire meal may pair with a musical tone, they add. E.S.'s ability to accurately relate musical intervals with specific tastes gives her an edge in the difficult task of interval identification.
The Swiss team notes that this raises the intriguing possibility "that synaesthesias may be used to solve cognitive problems" such as figuring out these musical intervals. This amusing perceptional tic may have practical value that would encourage evolution to favor its development. Studying it helps neuroscientists in their larger task of trying to understand how our cognitive system works as a whole.
Probing our ability to make and appreciate music is on the cutting edge of that research. Art and culture "must have their origin in the function and structure of the human nervous system," explains Robert Zatorre, a neuroscientist at the Montreal Neurological Institute in Canada, in the current issue of Nature.He adds that "listening to and producing music involves a tantalizing mix of practically every human cognitive function."
Our musical proclivities have deep roots. New babies show appreciation of music and recognize tones and tunes. Singing, dancing, and tapping feet to snappy rhythms are common skills. Organizing words into meaningful sentences looks a lot like organizing notes into musically meaningful sequences. Are language ability and musical ability linked? Dr. Zatorre asks. "Maybe music ... manages to transcend mere perception precisely because it contacts our more primordial neurobiology," he adds.
Those who prefer a classical symphony to a rap concert on the street - and the rappers also - should realize this possibility. Whatever their musical taste, humans share a common neurobiological ability to enjoy rhythm and melody. Those who can perceive music with more than one of their five senses owe special gratitude to that heritage.