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The 12th annual musical soiree of the CAS astronomy and physics departments, Friday, April 26, 7 p.m., Tsai Performance Center
Week of 19 April 2002 · Vol. V, No. 31

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Can you hear a color?
BU researchers explore the strange world of synesthesia

By Brian Fitzgerald

Imagine seeing a series of triangles every time a telephone rings, or experiencing the taste of chocolate on your tongue every time you see a tree. Welcome to the world of synesthesia, where the senses mingle freely and uncontrollably, a world where you hear certain colors and see certain sounds.

Alice Cronin-Golomb Photo by BU Photo Services


Alice Cronin-Golomb Photo by BU Photo Services


Synesthesia is a brain condition that occurs in roughly one of every 100,000 people, according to much of the literature on the subject. Some scientists, however, say it affects one in 25,000 people. Alice Cronin-Golomb, a CAS associate professor of psychology, believes that it is even more prevalent. "I think many people have it, but don't know that they have it," she says.

One of her students, Katherine Bangen (CAS'02), is researching this phenomenon for her senior Work for Distinction project in a psychology department study. "Synesthesia is a fascinating topic," says Bangen. "It involves the linking of the senses. When one individual is presented with stimuli in one modality, he has a subjective perceptual experience in a second modality. It can occur across all modalities, but I am researching colored-hearing synesthesia in particular."

This year, Bangen recruited subjects for the study and screened them to determine if they were truly synesthetic. "When a colored-hearing synesthete hears a word or a letter," she says, "a color is elicited internally in his mind's eye. It is an automatic process, and the colors remain consistent across years. In addition, these colors are very idiosyncratic -- the letter B may elicit red for one individual, but aquamarine for a second."

The study involves "manipulating the strength of the colored-hearing association to see if we can relate it to learning and memory abilities," says Cronin-Golomb. "We're trying to determine whether or not we can enhance the ability to remember something by changing the background color of a word. If the color that we choose is the one that matches what the synesthete would pick for a certain word, we want to know if he would be able to remember that information better than if we had picked a color that isn't a match for that word in his mind."

Synesthesia isn't Cronin-Golomb's chief area of interest. As director of the CAS Vision and Cognition Laboratory, she usually conducts research on visual factors influencing high-order cognitive capabilities in aging and age-related neurological disease, including Alzheimer's disease. She became fascinated with the topic of synesthesia, however, while getting her Ph.D. in psychobiology at the California Institute of Technology.

"When I was an undergraduate at Wesleyan University, my housemate, Tina, had synesthesia," she says. "So, when I read a paper on it at Cal Tech, I sent it to her."

Now, every fall Cronin-Golomb invites Tina to speak to her undergraduate neuropsychology class and her graduate clinical neuropsychology class. "I want my students to understand that not everything odd about the brain is bad," she says. "Some things can even enhance life." Indeed, some artists who are synesthetes see the condition as a wonderful gift. For example, New York artist Carol Steen uses the shapes and colors she experiences through music to inspire her paintings and sculptures.

"Some of the more famous synesthetes are physicist Richard Fineman, writer Vladimir Nabokov, and composer Alexander Scriabin," says Cronin-Golomb. Scriabin (1872-1915) specifically sought to express his synesthesia in his 1910 symphony Prometheus, the Poem of Fire, for orchestra, piano, organ, and choir. It also includes a mute keyboard -- a clavier à lumières -- which controls the play of colored light in the form of beams, clouds, and other shapes.

"Colored-hearing is the most common kind of synesthesia," says Cronin-Golomb. "That's what Tina has. It's driven by the first letter of the word, and she has a color for every letter. If you say the word apple, the word appears to her in blue. For other people, digits have very strong colors associated with them. Some people have colored-music synesthesia -- they hear a tone and see a color."

Neurologist Richard Cytowic, the author of The Man Who Tasted Shapes, had a neighbor who experienced flavors in the form of shapes that he felt rubbing against his face. After putting sauce on a roast chicken and tasting it, he blurted out, "Oh dear, there aren't enough points on the chicken." He then explained what he meant to Cytowic. "I wanted the taste of this chicken to be a pointed shape, but it came out all round."

Cronin-Golomb says that these associations are not learned. "At first, Tina thought that she must have learned this from some alphabet book when she was little," she says. "Many years later, she went back to the library in her hometown where she used to borrow books. She actually found the same book, and she was so sure that she would find all these colors there, but they weren't. It also runs in families. Her brother has it."

Synesthetes lead normal lives, and they do not consider this condition to be a disability, according to Cronin-Golomb. In fact, most of them think of it as an added bonus to their normal sensory perceptions. However, Cytowic writes that although synesthetes are typically intelligent and have excellent memories, research shows that the majority have subtle mathematical difficulties.

Synesthesia, which means "joined sensation" according to the Greek roots that make up the word, has been known to medicine for about 300 years.

Curiosity on the subject peaked between 1860 and 1930, but its cause remains a mystery. There isn't much scientific literature on synesthesia, but there has been an explosion of interest lately, with articles in the New York Times and Time magazine. The most recent book, John Harrison's Synesthesia: the Strangest Thing, focuses on a series of experiments on colored-hearing synesthesia. "It's coming back," says Cronin-Golomb, who attended a symposium on the subject sponsored by the Cognitive Neuroscience Society in March in San Francisco.


19 April 2002
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