The long a of the English alphabet…has for me the tint of weathered wood, but a French a evokes polished ebony. This black group also includes hard g (vulcanized rubber) and r (a sooty rag being ripped). Oatmeal n , noodle-limp l , and the ivory backed hand mirror of o take care of the whites.
–Nabokov, Speak Memory 1966
Synaesthesia challenges the classic view of perception, first formulated by Aristotle, that each of the five senses–sight, sound, hearing, taste, and touch–has a distinct and proper sphere of activity (Gage 348). (See Ear, Eye and Gaze, and Senses) Derived from the Greek syn (meaning union) and aesthesis (sensation), the term synaesthesia is used to describe the “production, from a sense impression of one kind, of an associated mental image of a sense impression of another kind” as well as “the production of a synaesthetic effect” through the “use of metaphor” (OED). The first definition refers primarily to a neuropsychological phenomenon, and is used to describe the experiences of those who hear colors, taste shapes, or otherwise demonstrate the capacity to experience two sensations simultaneously as the result of exposure to a single stimulus (Gage 348). The latter definition describes attempts made to simulate this experience through the use of aesthetic techniques, such as metaphor. Both types of synaesthetic experience raise questions, articulated in W.J.T. Mitchell’s essay “Word and Image,” about the ‘natural’ semiotic and aesthetic order…The nature of the senses, the media, the forms of art is put into question: natural for whom? since when? and why?” The term synaesthesia works both to describe the abnormal perceptions of a small group of people, and to reveal what ‘normal’ perceptions are thought to be.
Testing the limits of ‘normal’ perception with techniques such as metaphor and symbolism, synaesthesia became a preoccupation of many in the late nineteenth century. The Symbolist poet Arthur Rimbaud is often cited as having demonstrated synaesthetic perception in his sonnet, Les Voyelles (1871). In the opening line of the sonnet, “A noir, E blanc, I rouge, U vert, O bleu: voyelles”, Rimbaud assigns color values to different vowels. In doing so, he seems to go a step beyond the experiments in synaesthetic technique carried out by his predecessor Charles Baudelaire, who created elaborate lists of sensory “correspondences”. Explaining Baudelaire’s system of correspondences, A.G. Lehmann writes:
On Baudelaire’s theory, every colour, sound, odour, conceptualized emotion (love, hate, cf affect), every visual image, even if complex (a ship, a carcass), is in some way bound up with an equivalent in each of the other fields: one only, we may infer. (207)
While the system works as synaesthesia on the level of metaphor, it is not necessarily a manifestation of the rare neuropsychological disorder. Baudelaire’s system depends on associations evoked by the content of a word. For example, in the poem Correspondences, he writes, “Il est des parfums frais comme des chairs d’enfants”: there are perfumes as fresh as children’s flesh (quoted in Baron-Cohen 99). On the other hand, because Rimbaud sensory connections are revealed in the experience of saying a word, he comes much closer to expressing or simulating the synaesthete’s experience. In Les Voyelles , the sounds made in the pronunciation of the each of the vowels in seems to evoke the color it is paired with (Gage 349). Despite their different approaches to synaesthetic experience, both Baudelaire and Rimbaud seized upon it as a means of innovation. Both wished to change fundamentally the way that people read, understood, and experienced poetry.
The line between synaesthesia as a physiological phenomenon (first definition) and synaesthesia as metaphor (second definition) is blurry. Telling the aesthete from the synaesthe has become a favorite occupation of those who have written about synaesthesia in recent years. In an article on synaesthesia and aesthetics, Jörg Jewanski reveals the problems of this practice: “The fundamental difficulty in assessing the artistic significance of synaesthesia is that in the case of many musicians and artists it is impossible to be sure whether they are experiencing synaesthesia, have a heightened sensitivity to interdisciplinary associations and/or are seeking new ways of expressing themselves by deliberately blurring the frontiers between the arts. However, from an aesthetic perspective, the practice of differentiating between ‘true’ synaesthetes and mere imitators is less important than understanding how and why artists turn to synaesthesia in an effort to “deliberately blur” the boundaries between “normal” and “abnormal” perception.”
In order to richly describe the ways in which artists like Rimbaud expressed or simulated synaesthetic experience, it is useful to determine what is unusual about the ways in which officially diagnosed synaesthetes perceive the world around them. Having developed more sophisticated techniques of monitoring activity in different parts of the brain, neurologists have been able to identify “objective physiological changes” that occur during synaesthetic perception (Cytowic 285). Neuropsychologists such as Richard Cytowic have developed tests, based on these observations, which can be used to determine whether or not someone is a true synaesthete. Cytowic emphasizes the involuntary nature of synaesthetic perception. In addition, he argues, synaesthesia can be differentiated from imagination. When a person imagines something, it is said that he perceives something in his “mind’s eye”. For the synaesthete, on the other hand, additional sense perception often is experienced outside of the body (Cytowic 1). Vladimir Nabokov illustrates this property of synaesthesia in a description of his experience of colored hearing (the most commonly reported type of synaesthetic experience), taken from his autobiography, Speak, Memory:
I present a fine case of coloured hearing. Perhaps ‘hearing’ is not quite accurate, since the color sensation seems to be produced by the very act of my orally forming a given letter while I imagine its outline (quoted in Harrison 131).
Regardless of whether Nabokov was truly a synaesthete in the physiological sense of the word, synaesthetics played a vital role in his creative processes. Many other artists, writers, and musicians also involved synaesthetic phenomena in the process of their compositions, typically with the aim of broadening the sensory experiences of those who come into contact with their work.
While some artists make a space in their work for synaesthetic perception through the use of sensory fusion, others elicit the same effect through abstraction. The Russian composer Aleksandr Scriabin falls into the former camp. In 1911, he composed Prometheus, The Poem of Fire for an orchestra, piano, organ, choir, and a “light organ” or “clavier à lumieres”. The light organ was a silent instrument that “could control the play of colored light in the form of beams, clouds, and so forth, flooding the concert hall and culminating in a white light so strong as to be ‘painful to the eyes’.” He also planned a piece called Mysterium, which was to include dance, and odors, in addition to music and colored lights. As the title suggests, this work was to move the audience beyond the realm of normal perception to a “supreme, final ecstasy” achieved through the fusion of sensory experiences (quoted in Cytowic 271).
Wassily Kandinsky hoped to achieve the same end through different means. For those seeking the spiritual in his abstract compositions, the possibility resides in the free interplay of color and music. According to Harrison, Kandinsky’s “intention was for his work to possess the quality of evoking sounds (klangen) in those who viewed his canvases”(127). Of course, whatever Kandinsky’s intensions might have been, it is difficult to evaluate the synaesthetic effect his work has on the viewer. While a “sender” like Scriabar or Kandinsky might infuse their work with real or simulated synaesthetic experience, this does not guarantee that their compositions are perceived as synaesthetic by a “receiver”.
Both Scriabin and Kandinsky tested the limits of their media. Scriabin asserted that color, light, and perfumes are tools external to the medium of music that should be at the disposal of the composer in the achievement of a total effect. Kandinsky, on the other hand, uncovered new possibilities within the medium of painting, questioning what it is and showing what it can be. In blurring the boundaries between arts, and destabilizing our notion of what a medium must be, Scriabin and Kandinsky raise questions about the way art–and more broadly, everything in the world around us–should be perceived. What happens when, in Baudelaire’s words, the senses become “deranged”, when they cannot be classified as acting within distinct spheres of activity? Synaesthesia forces us to question our assumptions about the relationship between perception and reality.
Cytowic, Richard E. Synaesthesia: A Union of the Senses. New York: Springer-Verlag, 1989.
Gage, John. “Synaesthesia,” The Encyclopedia of Aesthetics, vol 4. Oxford UP, 1998. 348-351.
Harrison, John. “Synaesthesia: the strangest thing”. Oxford UP, 2001.
Jewanski, Jörg. “Colour and music.” The New Grove Dictionary of Music Online. ed. L. Macy (Accessed Jan 2003)
Lehmann, A.G. “Baudelaire and Synaesthesia”. The Symbolist Aesthetic in France 1885-1895. Oxford UP, 1968.
Mitchell, W.J.T. “Word and Image”.Critical Terms for Art History. Chicago: University of Chicago Press.
” Synaesthesia”. Oxford English Dictionary Online. 2nd edition. (Accessed Jan 2003)
“Machines take over functions of the central nervous system, and no longer, as in the past, merely those of muscles. And with this differentiation – and not with steam engines and railroads – a clear division occurs between matter and information, the real and the symbolic” (Kittler, GFT, 16).
The January 2002 issue of Artforum included the following letter to the editor and response: ”Peter Plagens describes Ada’s Garden as having a green background. The background is dark gray. It is depressing to have my paintings reviewed by a critic who is inattentive or color blind.”
–Alex Katz, New York
“English racing green” isn’t green as in Kelly, but rather almost black. And that’s the color I saw in the painting. But if Mr. Katz wants to swear that there’s absolutely no green paint mixed into his “dark gray,” then I’ll concede that my perception was affected by a combination of gallery lighting and a little synaesthesia from the title, Ada’s Garden.
Derived from anaesthesia (loss of feeling or sensation), the term synaesthesia is formed by combining syn (with, together, similarity, alike) and aesthesia (to feel, perceive). Commonly defined as “A sensation in one part of the body produced by a stimulus applied to another part –or- Production, from a sense-impression of one kind, of an associated mental image of a sense-impression of another kind,”  synaesthesia results from the subject’s interaction with media and is not itself a medium. Rather, it is the product of a process of mediation. Taking the first definition literally, one could conclude that sexual arousal, as a sensation felt in one part of the body instigated through stimulus applied to another part of the body, is a kind of synaesthetic experience. When one becomes sexually aroused as a result of viewing a nude, through scents, tastes, or by touch — which in the case of the kiss can involve both the tactile and taste –- sensation is transferred through the body from one part to another. The body, in this instance, serves as an enormous sensing or mediating organ. More common, however, is the second definition of the term in which synaesthesia is used to describe the human mind’s ability to confuse “sense-impressions.” For example, Plagens’ use of the active verb “to affect” points to how the word garden acted upon the critic’s visual capacities, hence causing him to see green where there was none. Although this form of synaesthesia is most commonly associated with “colored-hearing” and as such the production of visual images resulting from aural stimulus, Plagens’ invocation of the term in describing how text colored the critic’s vision of a painting indicates its potential application to multiple and mixed media. In other words, one can experience synaesthesia in reaction to a variety of media.
Given that the term can be defined both as a physical sensation felt in and through the body as well as a “sense-impression” mistranslated by the mind in which one sense is replaced by another, then the question is not how synaesthsia acts as medium, but rather which media elicit a synaesthetic response — whether bodily or psychological — in the subject and which subjects are prone to synaesthesia. While the term synesthétique did not enter the French dictionary until 1872, the synaesthetic had been invoked as early as 1690 when John Locke, in his “Essay Concerning Human Understanding,” tells of a blind man who when asked to describe the color scarlet, responded by stating that “it [scarlet] was like the sound of a trumpet.”  It was in the 19th-century, however, that cases of synaesthesia began to be documented, leading to formal studies of the “condition” by both neurologists and experimental psychologists. Studied to this day as a medical condition, a distinction need be made between synaesthesia that results from a developmental or neurologically dysfunctional process of the brain and what Baron-Cohen and Harrison consider pseudosynaesthesia, which is invoked by the subject as metaphor or is the effect of drug use. 
Through extensive neurological testing, it can be determined that one’s brain is able to involuntarily associate color with sound. Cases of such scientifically legitimate synaesthesia, however, are exceedingly rare and the precise neurological function of the brain responsible for the multiple sensations remains unknown. Most often, the subject (like Plagens) voluntarily makes metaphorical associations between sound and color. French phenomonologist M. Merleau-Ponty contends, however, that “Synaesthetic perception is the rule, and we are unaware of it only because scientific knowledge shifts the center of gravity of experience, so that we have unlearned how to see, hear, and generally speaking feel.”  Regardless of this debate concerning science and the subject’s alienation from his body, it is pseudosynaesthesia that has been employed by writers, composers, and visual artists who since the late 19th-century have manipulated their media with hopes of (re)creating a “legitimate” or clinical synaesthetic response in the subject.
Of numerous literary examples, the Symbolist poet Charles Baudelaire often invoked “a unity of sensation” in his texts and Harrison and Barron-Cohen believe this to reflect the poet’s belief that there existed a “natural correspondence between the senses.”  For example, In Correspondences, he includes the lines:
Like long echoes that mingle from far away
In profound and shadowy unity
Vast like the night and like clarity
Scents, sounds and colours respond to one another
This example, however, is less evocative of the concept than Plagens’ simple transfer of color onto text. In fact, Harrison and Barron-Cohen contend that it is much more common for single words or even fragments of words (sounds) to bring about a color association in the subject. As such, in Correspondences Baudelaire represents a synaesthetic sensibility rather than a vehicle for synaesthesia itself.
In music, Alexander Scriabin is most closely associated with the concept. In his orchestration of Prometheus, the composer included a “color organ.” Each pitch of the keyboard associated with a different color, the instrument produced color rather than sound when played. Scriabin claimed, as did many other composers and artists working in the early 20th-century, that his experience with music was one of synaesthesia. By adding a visual element to an otherwise aural medium in Prometheus, he attempts realize externally, his internal associations of color and sound.
In the visual arts, Wassily Kandinsky (a contemporary of Scriabin) is most noted for aspiring to produce synaesthetic painting. Like Scriabin, he too believed that his experience of color was one of sound and vibration. As elaborated in his Concerning the Spiritual in Art, the artist believed that vibrations of color and form could be collected into a universal language (a type of semiotic) that the viewing subject could instinctively comprehend. Although, much has been written on his mission’s shortcomings, his desire was to replicate his experience of the synaesthetic through the medium of painting.
It is, however, Richard Wagner who in the late 19th-century famously desired to create what we would consider a multi-media experience today. In his operas, Wagner sought to unite the visual, the aural, and narrative text into a single artistic unity or gesamtkunstwerk. The viewing subject was to be enveloped by sound, vision, and text, creating an experience not in which one sense was replaced by another, but rater an experience in which the senses intermingled and perhaps ultimately became one. This transcendental form of synaesthesia is perhaps most akin to what one experiences today in our world of multi-media(s), like film and the internet, in which media are constantly intertwined.
Instances in which media elicit the sensation of smell, touch, or taste through an unrelated sense are relatively rare. As is evident in the above examples in which a the visual and the aural are synaesthetically interchanged, the predominance of synaesthetic linkages between these two senses may be due to the audio-visual nature of media itself.
Jeffrey T Saletnik
Department of Art History
Dann, Kevin T. Bright Colors Falsely Seen: Synaesthesia and the Search for Transcendental Knowledge. New Haven: Yale UP, 1998.
Gage, John. “Synaesthesia” inEncyclopedia of Aesthetics. New York: Oxford UP, 1998.
Harrison, John and Simon Barron-Cohen. “Synaesthesia: An Account of Coloured Hearing” Leonardo, vol 27, no 4 (1997): 343-346
____., eds. Synaesthesia: Classic and Contemporary Readings. Oxford: Blackwell Publishing, 1997.
Jewanski, Jorg. “Synaesthesia” in New Grove Dictionary of Music. New York: Grove Dictionaries, Inc., 2001.
Kaplan, Julius. “Symbolism” in Grove Dictionary of Art. New York: Grove Dictionaries, Inc., 1999.
Oxford English Dictionary (on-line version)
 Letters to the Editor, Artforum (Jan 2002): 20.
 Oxford English Dictionary: Synaesthesia.
 See John E. Harrison and Simon Barron-Cohen’s text Synaesthesia: Classic and Contemporary Readings (Oxford: Blackwell Publishers, 1997): 4 for a discussion of the history of synaesthesia.
 See John E. Harrison and Simon Barron-Cohen’s text Synaesthesia: Classic and Contemporary Readings (Oxford: Blackwell Publishers, 1997): 11-12.
 M. Merleau-Ponty cited by John Harrison and Simon Baron-Cohen in “Synaesthesia: An Account of Coloured Hearing” Leonardo, vol 27, no 4 (1994): 343-346. They cite M. Merleau-Ponty, Phenomonology of Perception . Translated from French by Colin Smith. (London: Routledge, 1962): 229.
 John Harrison and Simon Baron-Cohen in “Synaesthesia: An Account of Coloured Hearing” Leonardo, vol 27, no 4: 343-346.