Chromesthesia is a perceptual phenomenon in which sounds automatically evoke the experience of a color. For those with the condition, music is seen as much as it is heard. A high-pitched sound suggests brightness. A low-pitched sound suggests something of a darker tone. The first recorded instance of chromesthesia comes from the English philosopher John Locke, who, in his Essay Concerning Human Understanding, wrote about a blind man. When asked what the color scarlet was, the blind man replied that it was akin to the sound of a trumpet.
