Imagine this scenario: it’s your second year of attending university, and you happen to come across an eye-catching poster on the back of a toilet stall. It reads, “What color is Monday? If you can answer that question, you might have synesthesia.” Staring in disbelief, you text one of your friends the same question, and get the response of “I have no idea what you’re talking about.” Suddenly, you realize that maybe what you’ve been experiencing your entire life isn’t exactly the norm.

This is the story of Holly Baxter, and seeing a color associated with Monday is an ordinary part of her day. She’s always known that Thursdays are dark blue, the names Audrey and Kirsty have the texture of folded curtains, and the word “enlightenment” is magenta with a bubble-like texture.

Holly’s condition is known as synesthesia. Simply defined, synesthesia is a sensation produced in one modality when a stimulus is applied to another modality, like when the hearing of a sound induces a vision of a color, or a word has a specific taste. Synesthesia has more than 80 identifiable types, some of the most common being grapheme-color, where letters and numbers have their own colors, and spatial-sequence, where numbers, months, and days of the week are located in specific places in space.

How Common is Synesthesia?

Combining all types of synesthesia, up to 4 percent of the global population is affected. Interestingly, the condition is most prevalent among artists, with an estimated 23 percent having synesthesia. This isn’t surprising when looking at the notable figures who are said to have or have had the condition, including Vincent Van Gogh, Kanye West, Billy Joel, Pharrell Williams, and Marilyn Monroe, among many others.

How Might Someone Develop Synesthesia?

The majority of synesthetes have had the condition for as long as they can remember. But, in rare circumstances, others have acquired it, typically from certain neurological conditions such as migraines and multiple sclerosis, or outside influences such as posthypnotic suggestion and drug use. Neuroscientists aren’t exactly sure what causes synesthesia, but for innate synesthetes, evidence points to more connections between parts of the brain responsible for sensory interpretation- typically visual, auditory, and intraparietal networks. Essentially, neurons and synapses that should be isolated to one sensory system happen to cross over to other sensory systems. For example, colored-hearing synesthetes have been shown to display activity in several areas of the visual cortex associated with processing color when they hear certain musical notes. One hypothesis proposes that crossed sensory connections are present in everyone at birth, but are refined during maturation. In synesthetes, these connections remain throughout adulthood and are not lost.

In addition to neurological differences, synesthesia also appears to have a genetic component- about 40 percent of synesthetes have a close relative with the condition. A 2018 study published in the Proceedings of the National Academy of Sciences identified 37 different genes with variants predictive of whether a person would have synesthesia. Six of these 37 are related to the process of axonogenesis, or the generation of a neuron’s axon (the part of a nerve cell that conducts electrical impulses away from the cell body and towards the receiving ends of other nerve cells).

What Benefits Does Synesthesia Entail?

Studies have shown that the condition definitely has its advantages; synesthetes have been proven to have a better color perception, stronger associations between sounds and shapes and heightened creativity, partially explaining why so many synesthetes are artists. Synesthesia can also be conducive to learning. They appear to be able to use their unusual experiences as mnemonic devices, proving useful while learning abstract concepts. Candita Wager, a synesthesia research assistant at UC Berkeley and a synesthete herself, says that everything she remembers is “a set of color combinations, whether it is the key that a song is in or a phone number.” Despite popular belief that synesthesia must be irritating and hinder focus, the condition can actually be quite helpful for syntheses like Candita who can use their synesthesia as a study tool or to foster creativity.

What’s Next For Synesthesia?

The future of synesthesia research looks promising. Wager, for instance, is designing a project that examines a possible link between synesthesia and left-handedness. Studying the condition could be particularly helpful in understanding how sensation and perception work in the brain. And this study published in the Frontiers in Psychology journal claims that synesthesia could be useful in the study of consciousness. Hopefully, by discussing synesthesia, public awareness of the condition will increase and any negative stigma surrounding the condition will be reduced.

So… what color is your Monday? 

Featured image via Pixabay.