Synesthesia

Synesthesia (American English) or synaesthesia (British English) is a perceptual phenomenon in which stimulation of one sensory or cognitive pathway leads to involuntary experiences in other sensory or cognitive pathways. Synesthesia can manifest as a bridge between the five traditional senses, though it can also include other perceptions, such as nociception, thermoception, chronoception, and interoception. People with synesthesia are referred to as synesthetes. Awareness of synesthetic perceptions varies from person to person with the perception of synesthesia differing based on an individual's unique life experiences and the specific type of synesthesia that they have. In one common form of synesthesia, known as grapheme–color synesthesia or color–graphemic synesthesia, letters or numbers are perceived as inherently colored. In spatial-sequence, or number form synesthesia, numbers, months of the year, or days of the week elicit precise locations in space (e.g., 1980 may be "farther away" than 1990), or may appear as a three-dimensional map (clockwise or counterclockwise). Synesthetic associations can occur in any combination and any number of senses or cognitive pathways. Little is known about how synesthesia develops. It has been suggested that synesthesia develops during childhood when children are intensively engaged with abstract concepts for the first time.…

Synesthesia (American English) or synaesthesia (British English) is a perceptual phenomenon in which stimulation of one sensory or cognitive pathway leads to involuntary experiences in other sensory or cognitive pathways. Synesthesia can manifest as a bridge between the five traditional senses, though it can also include other perceptions, such as nociception, thermoception, chronoception, and interoception. People with synesthesia are referred to as synesthetes. Awareness of synesthetic perceptions varies from person to person with the perception of synesthesia differing based on an individual's unique life experiences and the specific type of synesthesia that they have. In one common form of synesthesia, known as grapheme–color synesthesia or color–graphemic synesthesia, letters or numbers are perceived as inherently colored. In spatial-sequence, or number form synesthesia, numbers, months of the year, or days of the week elicit precise locations in space (e.g., 1980 may be "farther away" than 1990), or may appear as a three-dimensional map (clockwise or counterclockwise). Synesthetic associations can occur in any combination and any number of senses or cognitive pathways. Little is known about how synesthesia develops. It has been suggested that synesthesia develops during childhood when children are intensively engaged with abstract concepts for the first time. The earliest recorded case of synesthesia is attributed to the Oxford University academic and philosopher John Locke, who, in 1690, made a report about a blind man who said he experienced the color scarlet when he heard the sound of a trumpet. However, there is disagreement as to whether Locke described an actual instance of synesthesia or was using a metaphor. The first medical account came from German physician Georg Tobias Ludwig Sachs in 1812. The term is from Ancient Greek ( , 'together') and ( , 'sensation'). |alt=A drawing of numbers 1-100 along an up-and-down path, periodically changing colors ]] In one of the most common forms of synesthesia, individual letters of the alphabet and numbers (collectively referred to as "graphemes") are "shaded" or "tinged" with a color. While different individuals usually do not report the same colors for all letters and numbers, studies with large numbers of synesthetes find some commonalities across letters (e.g., A is likely to be red). Some authors have argued that the term synaesthesia may not be correct when applied to the so-called grapheme–colour synesthesia and similar phenomena in which the inducer is conceptual (e.g. a letter or number) rather than sensory (e.g. sound or color). They have postulated that the term 'ideasthesia' is a more accurate description. from one of Francis Galton's subjects (1881). Note how the first 4 digits roughly correspond to their positions on a clock face.|alt=diagram of numbers along a convoluted right-to-left path]] A number form is a mental map of numbers that automatically and involuntarily appears whenever someone who experiences number-forms synesthesia thinks of numbers. These numbers might appear in different locations and the mapping changes and varies between individuals. Number forms were first documented and named in 1881 by Francis Galton in "The Visions of Sane Persons". color area). |alt=3D graphic of a brain with 2 adjacent regions highlighted in green and red]] As of 2015, the neurological correlates of synesthesia had not been established. Dedicated regions of the brain are specialized for given functions. Increased cross-talk between regions specialized for different functions may account for the many types of synesthesia. For example, the additive experience of seeing color when looking at graphemes might be due to cross-activation of the grapheme-recognition area and the color area called V4 (see figure). This is supported by the fact that grapheme–color synesthetes can identify the color of a grapheme in their peripheral vision even when they cannot consciously identify the shape of the grapheme. An alternative possibility is disinhibited feedback or a reduction in the amount of inhibition along normally existing feedback pathways. Normally, excitation and inhibition are balanced. However, if normal feedback was not inhibited as usual, then signals feeding back from late stages of multi-sensory processing might influence earlier stages such that tones could activate vision. Cytowic and Eagleman find support for the disinhibition idea in the acquired forms of synesthesia that occur in non-synesthetes under certain conditions: temporal lobe epilepsy, head trauma, stroke, and brain tumors. They also note that it can likewise occur during stages of meditation, deep concentration, sensory deprivation, or with the use of psychedelics such as LSD or mescaline, and even, in some cases, marijuana. However, synesthetes report that common stimulants, like caffeine and cigarettes do not affect the strength of their synesthesia, nor does alcohol. A very different theoretical approach to synesthesia is that based on ideasthesia. According to this account, synesthesia is a phenomenon mediated by the extraction of the meaning of the inducing stimulus. Thus, synesthesia may be fundamentally a semantic phenomenon. Therefore, to understand neural mechanisms of synesthesia the mechanisms of semantics and the extraction of meaning need to be understood better. This is a non-trivial issue because it is not only a question of a location in the brain at which meaning is "processed" but pertains also to the question of understanding epitomized in e.g., the Chinese room problem. Thus, the question of the neural basis of synesthesia is deeply entrenched into the general mind–body problem and the problem of the explanatory gap. |alt=An abstract watercolor illustration using pink & blue colors|229x229px]] Wassily Kandinsky (a synesthete) and Piet Mondrian (not a synesthete) both experimented with image–music congruence in their paintings. Georgia O'Keeffe gave titles to several of her paintings, e.g. Blue and Green Music (1919–1921), using music–color associations. Contemporary artists with synesthesia, such as Carol Steen (a photographer who waits until she gets a synesthetic response from what she sees and then takes the picture), use their synesthesia to create their artwork. Linda Anderson, according to NPR considered "one of the foremost living memory painters", creates with oil crayons on fine-grain sandpaper representations of the auditory-visual synaesthesia she experiences during severe migraine attacks. Brandy Gale, a Canadian visual artist, experiences an involuntary joining or crossing of any of her senses hearing, vision, taste, touch, smell and movement. Gale paints from life rather than from photographs and by exploring the sensory panorama of each locale attempts to capture, select, and transmit these personal experiences. David Hockney perceived music as color, shape, and configuration and used these perceptions when painting opera stage sets (though not while creating his other artworks). Kandinsky combined four senses: color, hearing, touch, and smell. , accompanying his symphonic poem The Sea|alt=A painting of boats on a large wave]] Several composers had experienced synesthesia. Mikalojus Konstantinas Čiurlionis, a Lithuanian painter, composer, and writer, perceived colors and music simultaneously. Many of his paintings bear the names of matching musical pieces: sonatas, fugues, and preludes. Alexander Scriabin composed colored music that was deliberately contrived and based on the circle of fifths, whereas Olivier Messiaen invented a new method of composition (the modes of limited transposition) specifically to render his bi-directional sound–color synesthesia. For example, the red rocks of Bryce Canyon are depicted in his symphony Des canyons aux étoiles... ("From the Canyons to the Stars"). New art movements such as literary symbolism, non-figurative art, and visual music have profited from experiments with synesthetic perception and contributed to the public awareness of synesthetic and multi-sensory ways of perceiving. Other composers who reported synesthesia include Duke Ellington, Nikolai Rimsky-Korsakov, and Jean Sibelius. Several contemporary composers with synesthesia are Michael Torke, and Ramin Djawadi, best known for his work on composing the theme songs and scores for such TV series as Game of Thrones, Westworld and for the Iron Man movie. He says he tends to "associate colors with music, or music with colors". British composer Daniel Liam Glyn created the classical-contemporary music project Changing Stations using grapheme–colour synesthesia. Based on the 11 main lines of the London Underground, the eleven tracks featured on the album represent the eleven main tube line colours. Each track focuses heavily on the different speeds, sounds, and mood of each line, and are composed in the key signature synaesthetically assigned by Glyn with reference to the colour of the tube line on the map. ==External links== The real reason so many great artists experience reality differently, Richard Cytowic

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