Definition of "synaesthesia"

M. [Théodore] Flournoy includes all the phenomena of "Colored Hearing" and of "Mental Forms" under the convenient and adequate name Synæsthesia—in place of which, to be sure, he himself usually employs the less defensible term Synopsie. […] The phenomena of synæsthesia are divided into three main groups: "photisms," among which are included, as by [Eugen] Bleuler and Lehmann, all the varieties of pseudo-chromesthesia; "Schemes," comprising not only "forms" (diagrammes) associated with series of words or numbers, but "symbols," or particular figures associated with single letters, numerals, colors and the like; and "personifications," in which the associated factor is no mere color or form, but has become richer and more concrete.

1893 July, Mary Whiton Calkins, “De Phénomènes de Synopsie. Par Th. Flournoy. Paris, Alean, 1893. [book review]”, in G[ranville] Stanley Hall, editor, The American Journal of Psychology, volume V, number 4, Worcester, Mass.: J. H. Orpha, publisher, page 550

Probably in all of us, though in some men much more distinctly than in others, there exist certain synæsthesiæ or concomitances of sense-impression, which are at any rate not dependent on any recognisable link of association.

1903, Frederic W[illiam] H[enry] Myers, “Sensory Automatism”, in Human Personality and Its Survival of Bodily Death [...] In Two Volumes, volume I, London, New York, N.Y.: Longmans, Green, and Co., […], paragraph 603, page 224

[…] R. H. Gault's case of synesthesia in a deaf and blind girl, who could distinguish colors by the sense of smell, […]

1926 July, Paul Campbell Young, “An Experimental Study of Mental and Physical Functions in the Normal and Hypnotic States: Additional Results”, in Margaret F[loy] Washburn, Karl M. Dallenbach, [Isaac] Madison Bentley, Edward G. Boring, editors, The American Journal of Psychology, volume XXXVII, Ithaca, N.Y.: Cornell University, footnote 6, page 346

Now just as normal perceptions in terms of sense organs different from those stimulated can be interpreted through common past experiences, so it is likely that synæsthesias may be partly explicable in terms of individual experiences.

1945, Julian Blackburn, “Introduction”, in Psychology and the Social Pattern (International Library of Sociology and Social Reconstruction; 251), London: Kegan Paul, Trench, Trübner & Co.; republished London: Routledge, 2013,

Into her darkness, a churning synaesthesia, where her pain was the taste of old iron, scent of melon, wings of a moth brushing her cheek.

1984, William Gibson, chapter 18, in Neuromancer (Sprawl; book 1), New York, N.Y.: Ace Books, page 221

For example, I myself have a type of synaesthesia: The sounds of musical instruments will sometimes make me see colors, about a yard in front of me, each color specific and consistent with the particular instrument playing.

2002, Sean A. Day, “What Synaesthesia Is (and Is Not)”, in Paul Mc Kevitt, Seán Ó Nualláin, Conn Mulvihill, editors, Language, Vision and Music: Selected Papers from the 8th International Workshop on the Cognitive Science of Natural Language Processing, Galway, Ireland 1999 (Advances in Consciousness Research; 35), Amsterdam, Philadelphia, Pa.: John Benjamins Publishing Company, page 171

Colour is the most commonly induced synaesthetic percept and it can be invoked not only by auditory stimuli, but also by smells, tastes and touch sensations […]. Other synaesthesiae include musical taste and smell, visual smell, perceptions of shaped or auditory pain, and polymodal synaesthesiae.

2003, Marina Rakova, “Across Sensory Modalities”, in The Extent of the Literal: Metaphor, Polysemy and Theories of Concepts, Basingstoke, Hampshire, New York, N.Y.: Palgrave Macmillan, section 4.2 (Seeing Sounds and Tasting Shapes), page 52

For me Saturday was a bright red color, just as the other days of the week were chromatically coded. […] This wasn't the true synæsthesia which is such a fascinating mystical hint, a loose thread in the fabric of perception left a-dangle, an unravelling which suggests that we could dissolve all our unreal categories.

2008, Adam Mars-Jones, “Permission to Die”, in Pilcrow: Novel, London: Faber and Faber; 1st paperback edition, London, 2009, page 231

Synaesthesia can occur particularly powerfully during mescalin and LSD intoxication, and is often given mystical significance.

2009, Graham Richards, Psychology: The Key Concepts (Key Concepts), London, New York, N.Y.: Routledge, page 244

[S]ynesthetes themselves can provide the indispensable cues to design a structured qualitative questionnaire: color synesthesias and their variations during sexual arousal, direct physical stimulation, and orgasm […] can help scientists differentiate the specific triggers and their characteristics.

2018 April, Helena Melero, “From Pain to Pleasure: A Neuroscientific Approach to Pain-color and Orgasm-color Synesthesias”, in M[ari]a José de Córdoba Serrano, Julia López de la Torre Lucha, Timothy B. Leiden, editors, Actas del ‘VI Congreso Internacional de Sinestesia, Ciencia y Arte + Actividades Paralelas 2018’: Alcalá la Real, Jaén (España), Granada, Spain: Fundació Internacional Artecittà, page 4, column 1

On a phonemic level, phenomena of synesthesia have often been described and studied. Practically all children and a good many adults—though for the most part adults will deny it—spontaneously associate sounds, whether phonemes or the timbre of musical instruments, with colors and forms.

1963, Claude Lévi–Strauss, “Postscript to Chapters III and IV”, in Claire Jacobson, Brooke Grundfest Schoepf, transl., Structural Anthropology: Translated from the French (Harper Torchbooks; TB5017), New York, N.Y.: Basic Books, pages 91–92

For one of the enigmatic features of synaesthesia is that, within a given cultural group, the kinds of associations made by different subjects occur according to statistically verifiable recurring patterns. As Jakobson explains, ‘when we ask whether /i/ or /u/ is darker, testing such phonic oppositions as grave vs. acute, some of the subjects may respond that this question makes no sense to them, but hardly one will respond that /i/ is the darker of the two’ […].

2007, Boris Wiseman, “Structuralism, Symbolist Poetics and Abstract Art”, in Lévi-Strauss, Anthropology, and Aesthetics (Ideas in Context; 85), Cambridge: Cambridge University Press, page 112

Linking moods with colours is one example of synaesthesia. […] As a tool for improving writing, the idea of synaesthesia is versatile and innovative. Why use only visual references to describe visual impressions? Why just describe sounds using sound-related words? Play with cross-matching the senses.

2006, Stephen Bowkett, “Descriptive Writing”, in Boys and Writing (Pocket PAL), London: Network Continuum Education, Continuum International Publishing Group, page 38

[I]t may be stated that the concept of synaesthesia is instrumental for understanding music videos, since videos are based on the soundtrack's visual associations. Yet to discuss associations here may cause some problems. […] [Nicholas Cook] seems to be relying on a rather normative conception of synaesthesia, which for its part supports the idea of absolute, nonrepresentational music. The implication of his discussion is that the "true" forms of music–image synaesthesia come only in the forms of perception of color or light when hearing a certain musical sound.

2007, Antti-Ville Kärjä, “Visions of a Sound Nation: Finnish Music Videos and Secured Otherness”, in Roger Beebe, Jason Middleton, editors, Medium Cool: Music Videos from Soundies to Cellphones, Durham, N.C., London: Duke University Press, page 181