Neuroscience, history and the arts. Synesthesia: is F-sharp colored violet?

It is generally agreed that synesthesia occurs when an individual receives a stimulus in one sense modality and experiences a sensation in another. Historical difficulties of subjecting cross-modality to rigid scientific analysis, however, has led commentators to cast the phenomenon in terms of abnormality, philosophy and metaphor. Clearly discernable patterns of correspondence were not obvious and the often contradictory historical data were comprised of lists of stimuli and synesthetic responses. For example, accounts such as those attributed to Scriabin and RimskyKorsakov equated colors with given musical notes and keys (e.g. see Cytowic 1995; Harrison, 2001). Yet, reportedly, Scriabin claimed the key of C-Minor was red, while Rimsky-Korsakov perceived it as white (Harrison, 2001). This confusing and haphazard body of work is now being re-visited as researchers design studies capable of examining cross-modal sensation from a neural perspective. Although exciting findings have reinvigorated synesthesia research, of greater interest is that many documented accounts that were perceived as incoherent now appear to be essentially correct in light of what laboratory experiments are revealing (Harrison, 2001; Mattingly et al., 2001; Ramachandran & Hubbard, 2001). Moreover, the validation of older accounts complements a long historical literature on sensory inter-relationships that is robust and cross-cultural. The range is particularly thoughtprovoking when contrasted with current research findings regarding the phenomena. One of the earliest efforts to make sense of these relationships was the Pythagorean quest to assign a particular color to each musical note, about the 6th century BCE. In more recent times, the list of famous figures who were involved with the synesthetic experience includes Charles Baudelaire, Arthur Rimbaud, Nikolai RimskyKorsakov, Alexander Scriabin, Vassily Kandinsky, Vladimir Nabokov, Sergei Eisenstein, Oliever Messiaen, David Hockney and Richard Feynman. These attributions are based on some of the intriguing comments we find in their writings or remarks they have made about their own work. In Journal of the History of the Neurosciences 2004, Vol. 13, No. 1, pp. 58–65