Nov. 22, 2006 -- Life is a feast -- literally -- for some people with a rare condition called synesthesia, a new study shows. Words are often experienced as tastes by them.
In synesthesia, people have unusual sensory experiences. For instance, someone with synesthesia might "hear" a sound when they see the color red.
Nature's latest issue includes a brief report on six people with a version of synesthesia in which they experience tastes upon hearing certain words.
The researchers include Julia Simner, DPhil, of the psychology department at Scotland's University of Edinburgh.
In an email to WebMD, Simner discusses her findings.
Participants in the study ranged in age from the early 20s to one lady in her 80s, Simner says. Five were female, one male. One was British, the rest American.
All had had synesthesia as long as they could remember and experienced food tastes in response to words, she says.
"The proportion of words that triggers taste varies from synaesthete to synaesthete, and for those in our study it ranged from about 15% of words, to one lady who experiences tastes for 100% of words," Simner says.
Tastes Like Earwax
Participants reported some elaborate taste sensations with words.
"All their tastes represent complex food experiences (e.g., salad with Caesar dressing; lightly buttered toast; the vanilla cream you get inside donuts) and some are brand-specific (e.g., Heinz tomato soup)," says Simner.
"Some tastes can be rather unpleasant, as for example, with the small number of words that trigger the taste of 'organic inedibles' (e.g., earwax)," she notes.
That specific type of synesthesia "is particularly rare -- so rare in fact that we don't have an exact idea of its prevalence," says Simner.
Perk or Pest?
Most people with synesthesia -- whom Simner calls synaesthetes -- don't mind having the condition, she says.
"The vast majority of synaesthetes see it in one of three ways: either they love it, or they're neutral ('It's like having a little finger -- it's just there'), or they think everyone has it," she says.
"Only a very small number are less keen, and these tend to be either those people who have a very large number of sensory crossings (e.g. one lady hears colours, sees sounds, tastes shapes, etc.) or they are those people who experience tastes," she says.
"Tastes seem to be particularly intrusive and can cause problems for those who experience them," Simner notes.
For example, she says one man who experiences tastes with words told her he finds the sensations "very distracting: they interfere in meetings, when he's reading, when he's driving and looking at road signs, etc."
"However, even he said he'd not lose it [synesthesia] if he had the choice," she adds.
In the study, Simner's team first screened participants to make sure they weren't bluffing about having synesthesia.
Next, the researchers showed each participant a series of pictures of unfamiliar items, like a platypus or castanets.
Participants were asked to name the pictured item, and what tastes, if any, they experienced with that word.
The goal was to stump participants in order to see if their synesthesia kicked in while they struggled to name the pictured item. The key question was which comes first: the word or the taste?
Food for Thought
In most cases, the participants could name the pictured item without much trouble.
But in 89 of 550 trials, they struggled with that task. And in 17 of those 89 trials, participants said they tasted the word before they could name it.
For instance, one woman said she tasted tuna while she was staring at the picture of castanets, trying to remember the word "castanet."
Why would she taste tuna when she saw a picture of castanets? The researchers don't say, but perhaps she subconsciously broke down the word "castanet" into cast-a-net, as in tuna net.
The researchers gave participants a pop quiz more than a year later to make double sure their synesthesia reports were genuine.
Last year, another synesthesia report appeared in Neuron's Nov. 3, 2005 edition.
Those researchers included Vilayanur Ramachandran, MD, PhD, director of the Center for Brain and Cognition at the University of California, San Diego.
Their study was a review of research done on the condition.
Synesthesia was first studied more than a century ago but has since "largely been treated as a curiosity in psychology and neuroscience," the California researchers note.
They add that "although the study of synesthesia has recently undergone resurgence, a great number of open questions remain."
For instance, Ramachandran's team points out that scientists don't yet know exactly how synesthesia happens. Studies of brains scans have shown "somewhat inconsistent" results, he says.