SYNAESTHESIA: Why Can Some People 'Hear' Colours ?

Around 4% of people on Earth experience a mysterious phenomenon known as synaesthesia.

The word itself has Greek roots. The Greek term συναισθησία translates as “to perceive together.” Those who experience it are called synaesthetes.

But what exactly is synaesthesia ?

It is the ability to experience one sense through another—a phenomenon in which a stimulus in one sensory pathway automatically triggers a response in another. It is when we hear a sound and instantly see a colour; or when we read a certain word and a specific hue appears in the mind’s eye. Sometimes, more than one response occurs at once.

One of the most common forms is seeing letters, numbers, or sounds as colours.

I can “hear” colours and “see” sounds—and one of my former piano students, now my colleague, can do the same.

For me, the same tone is not always the exact same colour. Its intensity shifts. For example, I “see” C as red—but sometimes it is a light, translucent red, like watercolour; other times it is vivid and saturated, like acrylic or oil paint. It depends on the instrument playing it. The colour changes its weight, its density—its presence.

My former student experiences it differently. She may perceive an entire word as a single colour—people’s names, for instance. She might hear the name “Elizabeth” and immediately see purple. She may forget the name itself, but she will always remember the colour attached to it.

The response is immediate. We do not choose it; it simply happens—even with new experiences. When I hear a piece of music for the first time, colours may appear effortlessly, without intention or control.

I can perceive a musical scale in a single colour, a phrase in shifting tones, or even an entire piano work as a constantly evolving palette.

But what causes synaesthesia ?

This condition has long puzzled scientists.

Research suggests that the brains of synaesthetes are more interconnected than those of people whose senses remain separate. Brain imaging shows that individuals who “hear” colours exhibit heightened activity when processing sound. These studies also reveal increased connectivity between regions of the brain responsible for different senses.

The question remains, however: what gives rise to this unique wiring ?

Ongoing and in-depth research into synaesthesia may offer a valuable window into how the human brain constructs sensory representations of the world itself.

Notably, several composers are believed to have experienced synaesthesia, including Alexander Scriabin, Jean Sibelius, Olivier Messiaen, György Ligeti, and Franz Liszt.

© Alternative Approach to Music: Inspiring - Healing - Empowering, Xenia Elizabeth Zilli