“Synesthesia,” derived etymologically from a term meaning “a union of the senses,” is a literary device commonly employed by masters of writing. Several texts central to the Concord Academy English curriculum explore this concept. In the 9th-grade English core text Frankenstein, the “creature” reflects on his first experience of the world: “A strange multiplicity of sensations seized me, and I saw, felt, heard, and smelt at the same time.” Discussed in 10th-Grade English, The Great Gatsby conveys a similar effect: “The lights grow brighter as the earth lurches away from the sun, and now the orchestra is playing yellow cocktail music, and the opera of voices pitches a key higher.” Beyond a powerful technique in literature, synesthesia is a scientific phenomenon. It is defined by the brain routing sensory information through multiple unrelated senses, thus the “smelling sounds” or “tasting words.”
This rare neurological condition is involuntary and automatic, and not linked to a disease; it seems to have a genetic component, though, in some cases, it can also develop later in life, with causes like the use of drugs, meditation, or head trauma. Many famous creative minds have experienced synesthesia, such as Vincent van Gogh and Vladimir Nabokov, as well as contemporary artists such as Billie Eilish, Lady Gaga, and Beyoncé. The Romantic composer and pianist Franz Liszt reportedly associated musical keys with colors and was quoted for giving directions like “A little bluer, if you please! This tone type requires it!”.
The brain operates on five main senses: sight, sound, smell, taste, and touch, following the steps of detection, signaling, and processing. People with synesthesia, however, experience these steps differently—the same information goes through their brain through two or more areas at once. This causes a primary effect, the direct translation of the sensory input, alongside a secondary effect, where a sense is working without any input.
An example of this is visual synesthesia, which can also happen in different ways. Seeing a projection from, say, hearing music or tasting food, means that the brain combines the secondary effect with its sense of sight. On the other hand, an “internal screen” involves an image inside one’s head without directly involving sight. Other types of synesthesia include day-color synesthesia (associating colors with days of the week), grapheme-color synesthesia (connecting letters, numbers, or symbols with specific colors), and hearing-motion synesthesia (such as hearing a “whoosh” sound when watching something go past).
Developmental and acquired synesthesia do not require treatment — fortunately, they usually do not interfere with people’s ability to concentrate. Drug-induced synesthesia, however, can happen at higher intensity and doses. The key difference is that such a form of synesthesia is not automatic, alters one’s perception, and makes one emotionally dependent. This may indicate that a person needs treatment for an overdose of certain psychedelic drugs.
Synesthesia intersects the worlds of art and neuroscience, existing both as a compelling literary device at the author’s command and a fascinating scientific phenomenon to be studied. Regardless of its different contexts, synesthesia reveals our mind’s extraordinary capacity to blend senses in unexpected ways, continuing our legacy of creativity and enriching the human experience of the world.