Synesthesia is a neurological condition estimated to affect around 1 to 5 per cent of the population. People with the condition feel the senses – smell, touch, sight, taste and sound – as cross-wired or mingled, and one sense blends into another. They might see green when they hear the violin, or taste tomato soup when they hear the word “netball”, or feel adamant that letters and numbers have genders and personalities (perhaps four is a grumpy older gentleman and the letter Q is a cheeky eight-year-old girl).
It is thought to run in families, but the exact underlying genes causing it are still unknown. What we do know is that in infancy, parts of the brain controlling the senses are wired together. As Dr Jason Bell from the University of Western Australia’s School of Psychological Science explains, when we grow older, these connections usually die off , but in synesthetes, some of these pathways remain and a sensation in one area of the brain triggers a response in another.
“Very early in life, there are additional connections between senses within the brain that become pruned as we develop,” he says. “You trim up and prune the connections that should be there and you remove or let atrophy those connections that shouldn’t be there.”
WAYS OF THINKING
These extra links between the senses may help with artistic endeavours. Reportedly, the names van Gogh, Franz Liszt and Vladimir Nabokov, and more recently, Geoffrey Rush, Beyoncé and Pharrell Williams, all count among synesthete ranks. This raises fascinating questions about the creative processes they used to produce their famous contributions to music, literature, art and film.
Dr Stephanie Goodhew is a senior lecturer in psychology at the Australian National University and lead researcher for a recent study that found creative fields have more than their fair share of synesthetes.
“Synesthetes are more likely to be involved in more creative pursuits. They’re more likely to be artists and writers, and those sorts of things,” she says.
Another curious connection is between synesthesia and autism. A recent study by a team of scientists from the University of Cambridge led by Professor Simon Baron-Cohen found a link between synesthesia and autism. While synesthesia occurred in 7.2 per cent of garden-variety individuals, the gure was 18.9 per cent for those with autism.
Based on a mixture of self-reporting and research, there are believed to be 80 varieties of synesthesia. The most common type of these is grapheme-colour – synesthetes who see letters, words and numbers as a particular colour. According to Dr Karen Whittingham, psychology lecturer at the University of NSW, synesthetes are quite likely to have more than one type and the types of the condition are further grouped into families. If you have grapheme-colour synesthesia, for example, you are most likely to have other similar types as well.
Even among people with the same type of synesthesia, two individuals will experience the same triggers differently. For one person, Monday might be coloured blue, for another it’ll be orange, and these associations are mostly random, although the culture and era we’re brought up in do seem to play a part as well, in uencing the pool of experiences they have to draw on. “Synesthetes are not constrained to Western cultures,” Whittingham says. “They’d have different food tastes related to their culture. You would expect to find that.”
Whittingham is actually a touch-colour synesthete herself as well as a researcher on the topic. When she broke her ankle, she saw it as bright green, but she only experiences something like this occasionally, not all the time.
She also notes that all of us have a weak form of synesthesia surrounding metaphors. “If you understand ‘sharp cheese’, ‘loud shirt’, ‘bright tone’, you’ve borrowed from one sense to describe another sense,” she says.
UPS & DOWNS
Apart from an affinity to the arts, there are several potential benefits to having synesthesia. Goodhew says it was previously thought synesthetes might have some sort of super-memory due to their condition. It turns out they likely have similar memory storage space as the rest of us, but they do have an advantage in retaining information.
“They probably don’t have massively different memory capacity, but they can use their synesthetic experience in quite strategic ways to do a lot better on memory tasks,” Goodhew explains.
One standard laboratory test for memory gives participants a list of words to remember and compare with another list they are shown later. Goodhew says synesthetes who associate words with colours use their ability like a memory trick to help them see the difference in the lists. An orange-coloured word might be absent from the second list and they’ll be more likely to realise this than someone who relies on memorising the words alone.
Bell agrees, and adds that this could help mathematicians and engineers absorb and process complex equations and concepts. “It’s the most obvious case where I can see it being a performance improvement. You’ve got additional cues to help you break up the chunks of information,” he says. While many synesthetes see the extra links or information their brain provides as an advantage, some can experience a feeling of annoyance or overwhelm.
“For some individuals, it creates a bit of difficulty in their reading because some synesthetes see colours in relation to the words and if they see something in a colour that doesn’t match their synesthetic experience, they can find that quite frustrating,” Goodhew says.
Synesthetes with rarer types of the condition can feel physically ill in relation to certain triggers. “There are some individuals who, when they hear speech, they get tastes and smells, and they can feel nauseous,” Bell says. “That can be disruptive to everyday life.”
For people who experience an adverse reaction like this to the condition, the extra pathways in the brain cannot be physically removed, but the effects can be lessened by gradual desensitisation and trying to reprogram the brain to associate the trigger with a more pleasant experience. “Someone who hears sounds and feels nauseous, if you try to pair those sounds with a positive smell or a food they like, you can kind of create a reduction in that adverse consequence by inputting an in uence that’s more positive,” says Bell.
Because it’s best characterised as a psychological phenomenon rather than a disease or medical condition synesthetes o en don’t seek any treatment or cure. There currently isn’t a pill available to treat the underlying cause. In any case, because the condition is not widely known, they might not realise they’re any different to anyone else in the first place.
“People will often go into adulthood before they realise this is a condition, so they’re going around assuming this is something that everyone experiences,” Goodhew says. She says they’ll o en either make an o -the-cu comment and someone will look at them strangely or they’ll hear or read about synesthesia and realise they have it.
According to Bell, once someone is suspected of being a synesthete, there are two main tests that can be performed. The first option is by repetition and checking for consistency in a person’s answers to certain questions.
“If a person says that they see twos as green and fives as orange, and they see all the numbers as having different colours, if they’re being true and faithful and that’s how they really interpret and perceive the world, if you ask them that question 10 times and across 10 weeks, you’re going to get exactly the same answer” Bell says.
The other method is by testing for ability. “If somebody is looking at a display and they’re looking for a number two among a screenful of fives, for typical individuals, that’s di cult. They have pretty much the same shape – they’re just turned around the other way. However, if you see them as different colours, then that’s an intrinsically easy task,” he says.
SPREADING THE WORD
Dr Goodhew believes it’s important to raise awareness of this rare condition so that synesthetes’ experiences aren’t ridiculed or dismissed when they raise them with other people.
“As a child, for example – if they talk about this sound being blue, their parents think that they’re being naughty or silly or something. If there’s a greater awareness that this is a phenomenon and what it is, then when people report these experiences, they’ll be taken as legitimate experiences and not something nonsensical,” she says.
In Whittingham’s opinion, we can all take something positive away from the existence of the phenomenon. “Synesthesia is a wonderful way of reminding us that we’re a very diverse group of human beings. There’s diversity all the way down to how you perceive the world.”