What is it like to have synesthesia?

Colours are often associated with emotions — it’s not uncommon to feel “blue” or be “green with envy”. For a small percentage of the population, however, links between colours and emotions are just the beginning. Synesthesia, a neurological trait that is estimated to be present in 2-4% of people, is defined as “the production of a sense impression relating to one sense or part of the body by stimulation of another sense or part of the body”. To put it simply: the stimulation of one sense (such as touch, sight, or hearing) triggers an involuntary link to another sense.

So how can this affect a person’s everyday life? It’s impossible to account for all of the possible forms of synesthesia – if we take into account the five basic senses, there are already over twenty forms possible. In reality, synesthesia is much more complex. Imagine ordinal-linguistic personification synesthesia, where ordered sequences are associated with specific personalities. A person with this form of perception may find 7 to be a cruel number, or think that “H” is a whiny letter. Additionally, studies have shown that if a person has one form of synesthesia, they are 50% more likely to experience another form as well. 

However, many people report associations such as days of the week with certain colours. This poses an interesting question; where does common association end and synesthesia begin? There a a few commonly-agreed upon criteria that can be helpful in clarifying the difference:

1. Involuntary and automatic perception – one of the most telling symptoms is the involuntary, immediate nature of the phenomenon. Rather than using mental effort to make an association, it’s instantaneous.
2. Consistent reactionary triggers – the same stimulation will occur time and time again, with no two different reactions ever occurring.
3. Simple and objective perceptions – rather than a sound producing an image of a distant thunderstorm or triggering a memory, the visualisation is a specific colour or taste.

Personally, I experience what is known as grapheme-colour synesthesia. To me, all letters, numbers, and similar symbols have a distinct colour. For example, “K” is as inherently yellow as it is a letter that makes a “kuh” sound. Every time I look at a text message, a page in a book, or sequence of digits, I simultaneously view the characters in the colour they outwardly appear and an assigned colour of my perception. However, until about six months ago, I had no idea this way of viewing the world was at all unusual. This is actually quite common – many synesthetes report having been incredibly surprised when they realised their condition was not universal.

Overall, synesthesia is an intriguing condition that psychologists and neurologists alike are still struggling to understand. Personally, I can’t imagine life without it – losing my synesthesia would be like losing my sense of smell! Pharrell Williams puts it well; “If it was taken from me suddenly I’m not sure that I could make music,” he’s said on the topic of his (sound-colour) chromesthesia,  “I wouldn’t be able to keep up with it. I wouldn’t have a measure to understand.”

Are you interested in learning more about this diverse neurological phenomenon? I highly recommend this TED-Ed video lesson or this article from Medical Daily.