Condition in which the stimulation of one sensory modality is perceived as sensation in a different modality, as when a sound produces a sensation of color.

The experience of involuntary sensory cross activation where the presentation of a particular stimulus elicits a secondary sensory-perceptual experience. It most commonly occurs in the association of color with linguistic stimuli such as letters, numbers, words, or music, but can also occur between other senses. Although synesthesia can be acquired or transient due to trauma or drug use, there is also a strong genetic component, with a prevalence of about 1 in 2,000 individuals and a female to male ratio of 6:1.

Synesthesia, neuropsychological trait in which the stimulation of one sense causes the automatic experience of another sense. Synesthesia is a genetically linked trait estimated to affect from 2 to 5 percent of the general population. Grapheme-colour synesthesia is the most-studied form of...