Synesthesia: Why some people taste, feel and see things differently

When Vivian Russo was three years old, the crafts table wasn’t just a place to express her creativity; it was a veritable buffet where she could “taste” shiny and colourful art supplies just by looking at them. This wasn’t a byproduct of her vivid imagination; Vivian has synesthesia, a neurological condition where one sense triggers an unrelated sense, causing the two to come together in an unexpected way. For Vivian, seeing colours or certain textures gives her a specific taste in her mouth, as real to her as if she were eating the food. The colour blue, for example, tastes like spoiled milk. Glitter is spicy.

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The condition, which is usually inherited, is frequently described as a cross-wiring of the senses, and that’s not far off the mark. Diffusion tensor imaging (DTI) of the brains of people with synesthesia suggests they might have a higher number of white matter tracks, which allows for greater connectivity between regions of the brain, or more pathways for messages to be sent. Julia Simner, a UK–based synesthesia researcher and the editor of the Oxford Handbook of Synesthesia, says synesthetes have “hyper-connected brains.” So, in a case like Vivian’s, instead of just seeing something blue and her eyes sending a message to the brain that registers “blue” along that pathway, a simultaneous message is sent along another pathway to her brain’s taste centre and registers “sour.”

The condition affects one in 23 adults—roughly 4.4 percent of the population—making it just as common as red-green colour blindness. But not many people have heard of it. There are a couple of explanations for that. First, some people aren’t even aware they have it until they’re adults—as kids, they just assume their peers “see” sounds or “taste” colours like they do.Also, there are at least 60 different kinds of synesthesia, ranging from the more common grapheme-colour type (when each letter or number appears as a specific colour in the mind’s eye; for example, “A” may always be seen as “red”), to the far less common sense-taste synesthesia experienced by Vivian. (Vivian once told her mom, Juniper Russo, that the word “synesthesia” tasted just like a banana, but greener). These many different types make it a condition that can be hard to recognize and diagnose.

Now that Vivian is five, the kindergartner from Chattanooga, Tenn., doesn’t taste colours or images as frequently, but she often describes her mood using colour: Green means she’s happy, while yellow means she’s feeling sad or sick. “She also says that soft, fuzzy things, like animals and blankets, make her feel warm in her belly,” says Russo. “Strangely, she experiences pain when she sees red with black spots, so she has a phobia of ladybugs.”

Russo also has synesthesia; for her, some types of music make her feel physically uncomfortable and certain people’s faces or voices give her physical sensations of relaxation and comfort. “When Vivian was a toddler, she started describing unusual or illogical reactions to things around her, like experiencing pain when she saw a painting that was in our home,” says Russo. She told their paediatrician about it, but the doctor viewed it as a curiosity, not a concern. While Vivian has never received a formal diagnosis, her mom knows she has synesthesia from her own observations, and feedback from Vivian’s teachers once she started school.

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In the first long-term childhood study on grapheme-colour synesthesia (the type in which letters and numbers appear coloured), researchers at the University of Edinburgh, in Scotland, followed 80 synesthetes from the time they were six until they were 10 years old, testing them three times to find out when and how these associations between symbols and colours develop. In most cases, the older the children got, the more fixed their colour associations became—at age six, only 34 percent of associations were fixed, whereas a year later, 48 percent were fixed, and at age 10, that number rose to 71 percent. But interestingly, three children who were synesthetes at age six or seven no longer saw coloured letters and numbers at age 10, demonstrating that synesthesia can disappear over time. Simner, who co-authored the childhood grapheme-colour study, postulates that a higher percentage of children than adults have synesthesia, but that some grow out of it by adolescence as abundant childhood brain connections are slowly pruned away.

In addition to impacting sense perception in specific ways, Simner says the hyper-connectivity of the brain may be at the root of synesthesia’s benefits for children, including better memory for colours, words and letters, as well as greater creativity. They can also possess the ability to experience music or art on a multi-sensory level.

“It’s one thing to hear a song or see a sculpture, but it’s another to experience an art form with your entire body,” explains Russo. “Synesthesia gives both Vivian and me a deeper appreciation for the arts.”

But the condition is not without its challenges. For example, Vivian is reclusive and nervous on the playground because of her fear of ladybugs. She also refused to use a particular school bathroom because its wall mural made her feel uncomfortable. Simner says that these kids can face hurdles in the classroom, depending on how they are affected by the condition. Some students might feel uncomfortable with certain coloured letters if they are the “wrong” colour and overlook them, or become distracted when music from a video or elsewhere causes them to “see” colours. Such challenges can be compounded by educators who don’t understand the condition or aren’t sensitive to the child’s unique perceptions.

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Cheryl Ward knows this all too well. A synesthete herself, Ward is the principal of the Heritage Academy in Ottawa, a school for children with learning disabilities such as dyslexia (which Ward also has), attention deficit disorder and anxiety issues . Ward believes that synesthesia is under-diagnosed; the screening test isn’t routinely administered, and the school system tends to focus on difficulties in language, math, memory and processing, rather than sensory perception. Over the course of her 18 years at the school, about 30 students have been identified as having synesthesia, which she considers a learning disability. “Anything that has the child learning differently when you’re presenting the information is a learning disability,” says Ward.

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Staff at the Heritage Academy follow a strict code of no perfume or jarringly patterned clothing, to minimize overwhelming sensory stimuli for the students. Only blue, purple or green markers are used on the white boards because these “cool” tones are easiest for most students to read, and the school’s interior is also painted in soft, calming shades of blue, green and light purple. “Everything is muted to allow for less stress and more focus for the students,” Ward explains. With the right learning environment and support, she says kids with synesthesia can thrive. Simner is motivated to continue her research into the condition by the many emails she receives from parents thanking her for showing them that their children are not alone. “Telling the parents of a child with synesthesia that it’s normal, that there are others with it – that’s very important to me,” Simner says. “I encourage them to embrace the positive and celebrate their differences.”

That’s what Juniper Russo does with Vivian.

“I talk to her often about the fact that people’s brains work in different ways and how it makes all of us special,” says Russo. “She’s eccentric in more ways than one, and I know that there’s nothing I can do to make her ‘normal,’ so I focus on making sure she is happy and healthy.”

Did you know?

• Children with synesthesia won’t know there’s anything different about their perception unless you overhear them talking about, say, tasting music, and ask them what they mean.

• There’s often a genetic component: If you have synesthesia, it’s more likely your children will have it, too.

• Most people with synesthesia were born with it; a small portion develop it after an event such as having a stroke or going blind.

• Famous synesthetes include Kanye West (he sees sounds) and Billy Joel (he sees coloured letters and musical genres).

Think you or your child has synesthesia? Take the test at synesthete.org

A version of this article appeared in our March 2014 issue with the headline "Is glitter spicy?" pp. 64-5.