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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.
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Alice Cronin-Golomb Photo by BU Photo Services |
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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
Boston University
Office of University Relations