History of synesthesia research: Difference between revisions
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{{quotation|A studious blind man, who had mightily beat his head about visible objects, and made use of the explication of his books and friends, to understand those names of light and colours which often came in his way, bragged one day, That he now understood what scarlet signified. Upon which, his friend demanding what scarlet was? The blind man answered, It was like the sound of a trumpet.|Locke, ''An Essay Concerning Human Understanding''<ref name = "Locke">Locke, J. (1689). ''An Essay Concerning Human Understanding'', Book III, Chapter IV, section 11</ref>}} |
{{quotation|A studious blind man, who had mightily beat his head about visible objects, and made use of the explication of his books and friends, to understand those names of light and colours which often came in his way, bragged one day, That he now understood what scarlet signified. Upon which, his friend demanding what scarlet was? The blind man answered, It was like the sound of a trumpet.|Locke, ''An Essay Concerning Human Understanding''<ref name = "Locke">Locke, J. (1689). ''An Essay Concerning Human Understanding'', Book III, Chapter IV, section 11</ref>}} |
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Whether this is an actually synesthesia, or simply reflects metaphorical speech, is debated.<ref name=":2">{{Cite journal|last=Jewanski|first=Jörg|last2=Day|first2=Sean A.|last3=Ward|first3=Jamie|date=2009|title=A Colorful Albino: The First Documented Case of Synesthesia, by Georg Tobias Ludwig Sachs in 1812 |
Whether this is an actually synesthesia, or simply reflects metaphorical speech, is debated.<ref name=":2">{{Cite journal|last=Jewanski|first=Jörg|last2=Day|first2=Sean A.|last3=Ward|first3=Jamie|date=2009|title=A Colorful Albino: The First Documented Case of Synesthesia, by Georg Tobias Ludwig Sachs in 1812|journal=Journal of the History of the Neurosciences: Basic and Clinical Perspectives|volume=18|issue=3|pages=293–303|doi=10.1080/09647040802431946|pmid=20183209}}</ref><ref name=":3">{{Cite web|url=https://www.britannica.com/science/synesthesia|title=Synesthesia|last=Herman|first=Laura M.|date=2018-12-28|website=Encyclopaedia Britannica|access-date=2019-01-25}}</ref> A similar example appears in [[Gottfried Wilhelm Leibniz|Leibniz]]'s ''[[New Essays on Human Understanding]]'' (written in 1704, but not published until 1764); indeed given that the ''New Essays'' is intended as a rebuttal to Locke, it may even have been the same individual. Although it is mainly speculation, there is reason to believe that the person Locke referred to was the mathematician and scientist [[Nicholas Saunderson]], who held the [[Lucasian Professor of Mathematics|Lucasian professor]] chair at [[Cambridge University]], and whose general prominence would have made his statements noticeable. In ''Letters on the blind'', [[Denis Diderot]], one of Locke's followers, mentions Saunderson by name in related philosophical reflections. |
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In 1710, Thomas Woolhouse reported the case of another blind man who perceived colors in response to sounds.<ref name = "Marks1975">{{cite journal | doi = 10.1037/0033-2909.82.3.303 | last1 = Marks | first1 = L.E. | year = 1975 | title = On colored-hearing synesthesia: Cross-modal translations of sensory dimensions |
In 1710, Thomas Woolhouse reported the case of another blind man who perceived colors in response to sounds.<ref name = "Marks1975">{{cite journal | doi = 10.1037/0033-2909.82.3.303 | last1 = Marks | first1 = L.E. | year = 1975 | title = On colored-hearing synesthesia: Cross-modal translations of sensory dimensions | journal = Psychological Bulletin | volume = 82 | issue = 3| pages = 303–331 | pmid = 1096209 }}</ref> Numerous other philosophers and scientists, including [[Isaac Newton]] (1704), [[Erasmus Darwin]] (1790) and [[Wilhelm Wundt]] (1874) may have referred to synesthesia, or at least synesthesia-like mappings between colors and musical notes. [[Henry David Thoreau]] remarked in a letter to [[Ralph Waldo Emerson]] in 1848 that a child he knew had asked him "if I did not use ‘''colored'' words.’ She said that she could tell the color of a great many words, and amused the children at school by so doing."<ref name="Thoreau">Sanborn, F.B. ''The Writings of Henry David Thoreau'', Vol. VI: Familiar Letters, part II, p. 150</ref> |
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== 19th century investigations == |
== 19th century investigations == |
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The first agreed upon account of synesthesia comes from German physician [[Georg Tobias Ludwig Sachs]] in 1812, who reports on his colored vowels as part of his PhD dissertation (on his albinism),<ref name=":2" /><ref>{{Cite web|url=https://blogs.scientificamerican.com/literally-psyched/from-the-words-of-an-albino-a-brilliant-blend-of-color/|title=From the words of an albino, a brilliant blend of color|last=Konnikova|first=Maria|date=2013-02-26|website=Scientific American|archive-url=https://web.archive.org/web/20160920114035/https://blogs.scientificamerican.com/literally-psyched/from-the-words-of-an-albino-a-brilliant-blend-of-color/|archive-date=2016-09-20 |
The first agreed upon account of synesthesia comes from German physician [[Georg Tobias Ludwig Sachs]] in 1812, who reports on his colored vowels as part of his PhD dissertation (on his albinism),<ref name=":2" /><ref>{{Cite web|url=https://blogs.scientificamerican.com/literally-psyched/from-the-words-of-an-albino-a-brilliant-blend-of-color/|title=From the words of an albino, a brilliant blend of color|last=Konnikova|first=Maria|date=2013-02-26|website=Scientific American|archive-url=https://web.archive.org/web/20160920114035/https://blogs.scientificamerican.com/literally-psyched/from-the-words-of-an-albino-a-brilliant-blend-of-color/|archive-date=2016-09-20|access-date=2019-01-25}}</ref> although its importance has only become apparent retrospectively.<ref>Mahling, F. (1926) Das Problem der `audition colorée': Eine historisch-kritische Untersuchung. Archiv für die gesamte Psychologie, 57, 165-301.</ref><ref name=":3" /> The father of [[psychophysics]], [[Gustav Fechner]] reported on a first empirical survey of colored letter photisms among 73 synesthetes in 1871,<ref>Fechner, Th. (1871) ''Vorschule der Aesthetik''. Leipzig: Breitkopf und Hartel.</ref><ref>Campen, Cretien van (1996). De verwarring der zintuigen. Artistieke en psychologische experimenten met synesthesie. ''Psychologie & Maatschappij'', vol. 20, nr. 1, pp. 10-26.</ref> followed in the 1880s by [[Francis Galton]].<ref name = "Galton1880a">{{cite journal | doi = 10.1038/021252a0 | last1 = Galton | first1 = F. | year = 1880a | title = Visualised numerals | journal = Nature | volume = 21 | issue = 533| pages = 252–256 | doi-access = free }}</ref><ref name = "Galton1880b">{{cite journal | last1 = Galton | first1 = F. | year = 1880b | title = Visualised numerals | url = https://zenodo.org/record/1429243| journal = Nature | volume = 21 | issue = 543| pages = 494–495 | doi=10.1038/021494e0}}</ref><ref name = "Galton1883">Galton, F. (1883). ''Inquiries into Human Faculty and its Development.'' London:Dent & Sons</ref> These early investigations aroused little interest, and the phenomenon was first brought to the attention of the scientific community. Research into synesthesia proceeded briskly, with researchers from England, Germany, France and the United States all investigating the phenomenon. These early research years corresponded with the founding of psychology as a scientific field (see [[history of psychology]]). By 1926, Mahling cites 533 published papers dealing with colored hearing (or hearing → color synesthesia) alone.<ref name = "Marks1975" /> |
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Although there is still debate as to when the first international academic conference to seriously look at synesthesia took place, a likely candidate is the following: From 2 – 5 March 1927, [[Georg Anschütz]] (who was once a student of [[Alfred Binet]]) presided over the convening of the first Kongresse zur Farbe-Ton-Forschung (Congress for Color-Tone Research), in Hamburg, Germany. A second congress took place 1 – 5 October 1930, in Hamburg, Germany;<ref>G. Anschütz Farbe-Ton-Forschungen: Bericht über den II. Kongress für Farbe-Ton-Forschung (Hamburg, 1–5 October 1930), 1931.</ref> the third from 2 – 7 October 1933; and the 4th and final conference in this series took place 4 – 10 October 1936.<ref name = "Jewanski1999">Jewanski, Jörg (1999). Ist C = Rot?, Sinzig:Studio</ref> |
Although there is still debate as to when the first international academic conference to seriously look at synesthesia took place, a likely candidate is the following: From 2 – 5 March 1927, [[Georg Anschütz]] (who was once a student of [[Alfred Binet]]) presided over the convening of the first Kongresse zur Farbe-Ton-Forschung (Congress for Color-Tone Research), in Hamburg, Germany. A second congress took place 1 – 5 October 1930, in Hamburg, Germany;<ref>G. Anschütz Farbe-Ton-Forschungen: Bericht über den II. Kongress für Farbe-Ton-Forschung (Hamburg, 1–5 October 1930), 1931.</ref> the third from 2 – 7 October 1933; and the 4th and final conference in this series took place 4 – 10 October 1936.<ref name = "Jewanski1999">Jewanski, Jörg (1999). Ist C = Rot?, Sinzig:Studio</ref> |
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== Modern research == |
== Modern research == |
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In the 1980s, as the [[cognitive revolution]] had begun to make discussion of internal states and even the study of [[consciousness]] respectable again, scientists began to once again examine this fascinating phenomenon. Led by Lawrence E. Marks<ref name = "Marks1975" /> and Richard Cytowic<ref name = "Cytowic2002">Cytowic, R. E. (2002). ''[http://cytowic.net/_Books/_books.html Synesthesia: A Union of the Senses, 2nd ed.]'' (First Edition, 1989) Cambridge, MA:MIT Press, {{ISBN|0-262-03296-1}}.</ref><ref name = "Cytowic2003">Cytowic, R. E. (2003). ''[http://cytowic.net/_Books/_books.html The Man Who Tasted Shapes, 2nd Ed.]'' (First ed. 1993) New York, NY:Tarcher/Putnam, {{ISBN|0-262-53255-7}}</ref> in the United States, and by [[Simon Baron-Cohen]] and Jeffrey Gray<ref name = "Baron-Cohen1997">Baron-Cohen, S. & J. E. Harrison (1997). ''Synaesthesia: Classic and Contemporary Readings.'' Malden, MA:Blackwell, {{ISBN|0-631-19764-8}}</ref> in England, research into synesthesia began by exploring the reality, consistency and frequency of synesthetic experiences. In the late 1990s, researchers began to turn their attention towards grapheme-color synesthesia, one of the most common<ref name = "Day2005">Day, S.A. (2005). Some Demographic and Socio-cultural Aspects of Synesthesia. in L. Robertson & N. Sagiv (Eds.) ''Synesthesia: Perspectives from Cognitive Neuroscience.'' Oxford:Oxford University Press. (p. 11-33). {{ISBN|0-19-516623-X}}</ref><ref name = "Rich2005">{{cite journal | doi = 10.1016/j.cognition.2004.11.003 | last1 = Rich | first1 = A.N. | last2 = Bradshaw | first2 = J.L. | last3 = Mattingley | first3 = J.B. | year = 2005 | title = A systematic, large scale study of synaesthesia: Implications for the role of early experience in lexical-colour associations |
In the 1980s, as the [[cognitive revolution]] had begun to make discussion of internal states and even the study of [[consciousness]] respectable again, scientists began to once again examine this fascinating phenomenon. Led by Lawrence E. Marks<ref name = "Marks1975" /> and Richard Cytowic<ref name = "Cytowic2002">Cytowic, R. E. (2002). ''[http://cytowic.net/_Books/_books.html Synesthesia: A Union of the Senses, 2nd ed.]'' (First Edition, 1989) Cambridge, MA:MIT Press, {{ISBN|0-262-03296-1}}.</ref><ref name = "Cytowic2003">Cytowic, R. E. (2003). ''[http://cytowic.net/_Books/_books.html The Man Who Tasted Shapes, 2nd Ed.]'' (First ed. 1993) New York, NY:Tarcher/Putnam, {{ISBN|0-262-53255-7}}</ref> in the United States, and by [[Simon Baron-Cohen]] and Jeffrey Gray<ref name = "Baron-Cohen1997">Baron-Cohen, S. & J. E. Harrison (1997). ''Synaesthesia: Classic and Contemporary Readings.'' Malden, MA:Blackwell, {{ISBN|0-631-19764-8}}</ref> in England, research into synesthesia began by exploring the reality, consistency and frequency of synesthetic experiences. In the late 1990s, researchers began to turn their attention towards grapheme-color synesthesia, one of the most common<ref name = "Day2005">Day, S.A. (2005). Some Demographic and Socio-cultural Aspects of Synesthesia. in L. Robertson & N. Sagiv (Eds.) ''Synesthesia: Perspectives from Cognitive Neuroscience.'' Oxford:Oxford University Press. (p. 11-33). {{ISBN|0-19-516623-X}}</ref><ref name = "Rich2005">{{cite journal | doi = 10.1016/j.cognition.2004.11.003 | last1 = Rich | first1 = A.N. | last2 = Bradshaw | first2 = J.L. | last3 = Mattingley | first3 = J.B. | year = 2005 | title = A systematic, large scale study of synaesthesia: Implications for the role of early experience in lexical-colour associations | journal = Cognition | volume = 98 | issue = 1| pages = 53–84 | pmid = 16297676 }}</ref> and easily studied forms of synesthesia. In 2006, the journal Cortex published a [http://www.cortex-online.org/cortex.asp?action=toArticles&folderID=176 special issue on synesthesia], composed of 26 articles from individual case reports to [[functional neuroimaging]] studies of the [[neural basis of synesthesia]]. Synesthesia has been the topic of several recent scientific books and novels and a recent short film has even included characters who experience synesthesia (for more information, see the main [[synesthesia]] page). |
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Mirroring these developments in the professional community, synesthetes and synesthesia researchers have come together to found several societies dedicated to research and education about synesthesia, its consequences and uses. In 1995, the [[American Synesthesia Association]] was founded, and has been having annual meetings since 2001. In England, the [[UK Synaesthesia Association]], arose out of a similar desire to bring together synesthetes and the people who study them, and has held two conferences (in 2005 and 2006). Similarly, since its inception in 1993, Sean A. Day has administered the "[http://www.daysyn.com/Synesthesia-List.html synesthesia list]", an e-mail list for synesthetes and researchers around the world. With increased scientific knowledge and public outreach, awareness of this condition is growing worldwide. |
Mirroring these developments in the professional community, synesthetes and synesthesia researchers have come together to found several societies dedicated to research and education about synesthesia, its consequences and uses. In 1995, the [[American Synesthesia Association]] was founded, and has been having annual meetings since 2001. In England, the [[UK Synaesthesia Association]], arose out of a similar desire to bring together synesthetes and the people who study them, and has held two conferences (in 2005 and 2006). Similarly, since its inception in 1993, Sean A. Day has administered the "[http://www.daysyn.com/Synesthesia-List.html synesthesia list]", an e-mail list for synesthetes and researchers around the world. With increased scientific knowledge and public outreach, awareness of this condition is growing worldwide. |
||
Revision as of 17:15, 15 December 2020
Synesthesia is a neurological condition in which two or more bodily senses are coupled. For example, in a form of synesthesia known as grapheme-color synesthesia, letters or numbers may be perceived as inherently colored. Historically, the most commonly described form of synesthesia (or synesthesia-like mappings) has been between sound and vision, e.g. the hearing of colors in music.
Early investigations of colored hearing
The interest in colored hearing, i.e. the co-perception of color in hearing sounds or music, dates back to Greek antiquity, when philosophers were investigating whether the colour (chroia, what we now call timbre) of music was a physical quality that could be quantified.[1] The seventeenth-century physicist Isaac Newton tried to solve the problem by assuming that musical tones and colour tones have frequencies in common.[2] The age-old quest for colour-pitch correspondences in order to evoke perceptions of coloured music finally resulted in the construction of color organs and performances of colored music in concert halls at the end of the nineteenth century.[2][3] (For more information, see the synesthesia in art page).
John Locke in An Essay Concerning Human Understanding' (1689) reports:
A studious blind man, who had mightily beat his head about visible objects, and made use of the explication of his books and friends, to understand those names of light and colours which often came in his way, bragged one day, That he now understood what scarlet signified. Upon which, his friend demanding what scarlet was? The blind man answered, It was like the sound of a trumpet.
— Locke, An Essay Concerning Human Understanding[4]
Whether this is an actually synesthesia, or simply reflects metaphorical speech, is debated.[5][6] A similar example appears in Leibniz's New Essays on Human Understanding (written in 1704, but not published until 1764); indeed given that the New Essays is intended as a rebuttal to Locke, it may even have been the same individual. Although it is mainly speculation, there is reason to believe that the person Locke referred to was the mathematician and scientist Nicholas Saunderson, who held the Lucasian professor chair at Cambridge University, and whose general prominence would have made his statements noticeable. In Letters on the blind, Denis Diderot, one of Locke's followers, mentions Saunderson by name in related philosophical reflections.
In 1710, Thomas Woolhouse reported the case of another blind man who perceived colors in response to sounds.[7] Numerous other philosophers and scientists, including Isaac Newton (1704), Erasmus Darwin (1790) and Wilhelm Wundt (1874) may have referred to synesthesia, or at least synesthesia-like mappings between colors and musical notes. Henry David Thoreau remarked in a letter to Ralph Waldo Emerson in 1848 that a child he knew had asked him "if I did not use ‘colored words.’ She said that she could tell the color of a great many words, and amused the children at school by so doing."[8]
19th century investigations
The first agreed upon account of synesthesia comes from German physician Georg Tobias Ludwig Sachs in 1812, who reports on his colored vowels as part of his PhD dissertation (on his albinism),[5][9] although its importance has only become apparent retrospectively.[10][6] The father of psychophysics, Gustav Fechner reported on a first empirical survey of colored letter photisms among 73 synesthetes in 1871,[11][12] followed in the 1880s by Francis Galton.[13][14][15] These early investigations aroused little interest, and the phenomenon was first brought to the attention of the scientific community. Research into synesthesia proceeded briskly, with researchers from England, Germany, France and the United States all investigating the phenomenon. These early research years corresponded with the founding of psychology as a scientific field (see history of psychology). By 1926, Mahling cites 533 published papers dealing with colored hearing (or hearing → color synesthesia) alone.[7]
Although there is still debate as to when the first international academic conference to seriously look at synesthesia took place, a likely candidate is the following: From 2 – 5 March 1927, Georg Anschütz (who was once a student of Alfred Binet) presided over the convening of the first Kongresse zur Farbe-Ton-Forschung (Congress for Color-Tone Research), in Hamburg, Germany. A second congress took place 1 – 5 October 1930, in Hamburg, Germany;[16] the third from 2 – 7 October 1933; and the 4th and final conference in this series took place 4 – 10 October 1936.[17]
In addition to drawing concerted scientific interest, the phenomenon of synesthesia started arousing interest in the salons of fin de siecle Europe. The French Symbolist poets Arthur Rimbaud and Charles Baudelaire wrote poems which focused on synesthetic experience. Baudelaire's Correspondances (1857) (full text available here) introduced the Romantic notion that the senses can and should intermingle. Kevin Dann argues that Baudelaire probably learned of synesthesia from reading medical textbooks that were available in his home,[18] and it is generally agreed that neither Baudelaire, nor Rimbaud were true synesthetes. Rimbaud, following Baudelaire, wrote Voyelles (1871) (full text available here) which was perhaps more important than Correspondances in popularizing synesthesia. Numerous other composers, artists and writers followed suit, making synesthesia well known among the artistic community of the day.
Due to the difficulties in assessing and measuring subjective internal experiences, and the rise of behaviorism in psychology, which banished any mention of internal experiences, the study of synesthesia gradually waned during the 1930s. Marks[7] lists 44 papers discussing colored hearing from 1900 to 1940, while in the following 35 years from 1940 to 1975, only 12 papers were published on this topic. Cretien van Campen graphed the number of publications in the period 1780 - 2000 and noticed a revival of synesthesia studies from the 1980s.[19]
Modern research
In the 1980s, as the cognitive revolution had begun to make discussion of internal states and even the study of consciousness respectable again, scientists began to once again examine this fascinating phenomenon. Led by Lawrence E. Marks[7] and Richard Cytowic[20][21] in the United States, and by Simon Baron-Cohen and Jeffrey Gray[22] in England, research into synesthesia began by exploring the reality, consistency and frequency of synesthetic experiences. In the late 1990s, researchers began to turn their attention towards grapheme-color synesthesia, one of the most common[23][24] and easily studied forms of synesthesia. In 2006, the journal Cortex published a special issue on synesthesia, composed of 26 articles from individual case reports to functional neuroimaging studies of the neural basis of synesthesia. Synesthesia has been the topic of several recent scientific books and novels and a recent short film has even included characters who experience synesthesia (for more information, see the main synesthesia page).
Mirroring these developments in the professional community, synesthetes and synesthesia researchers have come together to found several societies dedicated to research and education about synesthesia, its consequences and uses. In 1995, the American Synesthesia Association was founded, and has been having annual meetings since 2001. In England, the UK Synaesthesia Association, arose out of a similar desire to bring together synesthetes and the people who study them, and has held two conferences (in 2005 and 2006). Similarly, since its inception in 1993, Sean A. Day has administered the "synesthesia list", an e-mail list for synesthetes and researchers around the world. With increased scientific knowledge and public outreach, awareness of this condition is growing worldwide.
See also
References
- ^ Gage, J. Colour and Culture. Practice and Meaning from Antiquity to Abstraction. (London:Thames & Hudson, 1993).
- ^ a b Peacock, Kenneth. "Instruments to Perform Color-Music: Two Centuries of Technological Experimentation," Leonardo 21, No. 4 (1988) 397-406.
- ^ Jewanski, J. & N. Sidler (Eds.). Farbe - Licht - Musik. Synaesthesie und Farblichtmusik. Bern: Peter Lang, 2006.
- ^ Locke, J. (1689). An Essay Concerning Human Understanding, Book III, Chapter IV, section 11
- ^ a b Jewanski, Jörg; Day, Sean A.; Ward, Jamie (2009). "A Colorful Albino: The First Documented Case of Synesthesia, by Georg Tobias Ludwig Sachs in 1812". Journal of the History of the Neurosciences: Basic and Clinical Perspectives. 18 (3): 293–303. doi:10.1080/09647040802431946. PMID 20183209.
- ^ a b Herman, Laura M. (28 December 2018). "Synesthesia". Encyclopaedia Britannica. Retrieved 25 January 2019.
- ^ a b c d Marks, L.E. (1975). "On colored-hearing synesthesia: Cross-modal translations of sensory dimensions". Psychological Bulletin. 82 (3): 303–331. doi:10.1037/0033-2909.82.3.303. PMID 1096209.
- ^ Sanborn, F.B. The Writings of Henry David Thoreau, Vol. VI: Familiar Letters, part II, p. 150
- ^ Konnikova, Maria (26 February 2013). "From the words of an albino, a brilliant blend of color". Scientific American. Archived from the original on 20 September 2016. Retrieved 25 January 2019.
- ^ Mahling, F. (1926) Das Problem der `audition colorée': Eine historisch-kritische Untersuchung. Archiv für die gesamte Psychologie, 57, 165-301.
- ^ Fechner, Th. (1871) Vorschule der Aesthetik. Leipzig: Breitkopf und Hartel.
- ^ Campen, Cretien van (1996). De verwarring der zintuigen. Artistieke en psychologische experimenten met synesthesie. Psychologie & Maatschappij, vol. 20, nr. 1, pp. 10-26.
- ^ Galton, F. (1880a). "Visualised numerals". Nature. 21 (533): 252–256. doi:10.1038/021252a0.
- ^ Galton, F. (1880b). "Visualised numerals". Nature. 21 (543): 494–495. doi:10.1038/021494e0.
- ^ Galton, F. (1883). Inquiries into Human Faculty and its Development. London:Dent & Sons
- ^ G. Anschütz Farbe-Ton-Forschungen: Bericht über den II. Kongress für Farbe-Ton-Forschung (Hamburg, 1–5 October 1930), 1931.
- ^ Jewanski, Jörg (1999). Ist C = Rot?, Sinzig:Studio
- ^ Dann, K. T. (1998). Bright Colors Falsely Seen: Synaesthesia and the Search for Transcendent Knowledge. Yale University Press., ISBN 0-300-06619-8.
- ^ Campen, Cretien van (1999) Artistic and Psychological Experiments with Synesthesia. Leonardo vol. 32, nr. 1, 9-14.
- ^ Cytowic, R. E. (2002). Synesthesia: A Union of the Senses, 2nd ed. (First Edition, 1989) Cambridge, MA:MIT Press, ISBN 0-262-03296-1.
- ^ Cytowic, R. E. (2003). The Man Who Tasted Shapes, 2nd Ed. (First ed. 1993) New York, NY:Tarcher/Putnam, ISBN 0-262-53255-7
- ^ Baron-Cohen, S. & J. E. Harrison (1997). Synaesthesia: Classic and Contemporary Readings. Malden, MA:Blackwell, ISBN 0-631-19764-8
- ^ Day, S.A. (2005). Some Demographic and Socio-cultural Aspects of Synesthesia. in L. Robertson & N. Sagiv (Eds.) Synesthesia: Perspectives from Cognitive Neuroscience. Oxford:Oxford University Press. (p. 11-33). ISBN 0-19-516623-X
- ^ Rich, A.N.; Bradshaw, J.L.; Mattingley, J.B. (2005). "A systematic, large scale study of synaesthesia: Implications for the role of early experience in lexical-colour associations". Cognition. 98 (1): 53–84. doi:10.1016/j.cognition.2004.11.003. PMID 16297676.