In a provocative review paper just published, French neuroscientists Jean-Michel Hupé and Michel Dojat question the assumption that synesthesia is a neurological disorder.
In synesthesia, certain sensory stimuli involuntarily trigger other sensations. For example, in one common form of synesthesia, known as ‘grapheme-color‘, certain letters are perceived as allied with, certain colors. In other cases, musical notes are associated with colors, or smells.
The cause of synesthesia is obscure. Many neuroscientists (including Hupé and Dojat) have searched for its brain basis. One theory is that it’s caused by ‘crossed wires’ – abnormal connections among the sensory processing areas of the brain.
But – according to Hupé and Dojat – the studies to date have failed to find anything, and the only conclusion we can draw from these studies is that “the brains of synesthetes are functionally and structurally similar to the brains of non-synesthetes.”
To reach this conclusion they reviewed ...
