Synesthesia is a condition that describes how senses blend to create a fuller sense of a color, object, taste or feeling. The word synesthesia means literally to join (syn) perceptions (thesia). The symptoms of this condition can vary dramatically, from mild experience to bizarre.
For some people, an orchestra playing Beethoven’s fifth symphony may suggest a very strong taste of ginger, whereas some with synesthesia may hear it and just imagine colors of gold and orange. Some people experience blue as both a color and a scent. Some people can taste Italian sauces when they hear a specific melody. Some can sense if a touch of the hand is purple or green.Some people can both see and hear, or even taste, a silent object such as “book.”
Doctors Richard Cytowic and David Eagleman have written about synesthesia in depth in their book: Wednesday is Indigo Blue. They use many direct stories from synesthetes (those who diagnosed with synesthesia), and the descriptions are intriguing. Their investigation looks at the many ways there are to perceive the world. They also suggest that new insights into cognitive neuroscience will be forthcoming as more is understood about just what qualifies as synesthesia, and what does not. At present, there is no absolute definition, but much crossover, as so much of the research is heavily dependent upon self-reports by synesthetes.
They find that although synesthesia does not dominate the lives of most synesthetes, there are real challenges. For example, cognitive thought challenges and sensory overload affect their perceptions in ways most cannot imagine. Try to imagine taking down directions from someone and perceiving a scent for every color, a texture for every number and a different spatial interpretation for every building on every block. There are no doubt some advantages to memory with so many associations, and some aspects of creativity that become possible. Still, the idea of only artists having synesthesia is debunked; that assumption is merely due to sample bias.
Synesthesia is suggested to be a normal feature that all human beings have at birth, but lose while very young. Shared fundamental traits called “form constants” are found. An example might be that more people will routinely perceive Beethoven as heavier than Tchaikovsky’s dance of the sugar plum fairy.
There are vastly different opinions as to how rare the condition is; some neurologists place it as high as one out of two hundred people experiencing it. It is known, however, that more women than men regularly experience synesthesia. Doctors have theorized there is a genetic component to synesthesia, and most researchers believe it is carried through the X chromosome, and so quite inheritable, possibly with evolutionary advantages in some environments.
There are many fascinating aspects of synesthesia. Many of those who have the condition are thought to be exceptionally creative. Some leading artists, such as Vasily Kandinsky, and famous scientists, such as physicist Richard Feynman, have been reported to be synesthetes. Many who have synesthesia are also left-handed, although most people who are left-handed do not report having the condition. When given neurological tests, it is found that people with synesthesia are normal in their neurological functioning, but also found to be above average in intelligence. All of this is still controversial, and disputed by some.
Finally, there is some research that shows mind-altering hallucinogens can produce the effect of synesthesia among people who had never tasted “pink,” smelled the light of the moon or seen the scent of fresh lemons. Research into the genetic and biological bases for synesthesia, and the fascination with all that is revealed, will certainly lead many to long to “see” the delightful, bright chirp of the morning lark.