The “golden age” of synesthesia inquiry in the late nineteenth century (1876–1895)

Abstract

Synesthesia is a rare neurological trait that causes unusual, often crosssensory, experiences (e.g., seeing colors when listening to music). This article traces the history of synesthesia in the period 1876 to 1895. In this period, there was considerable debate over the nature of synesthesia, its causes, and how it should be named. The issue also attracted the leading thinkers of the time and, within a few years, the number of reported cases of synesthesia jumped from around ten to more than 100. For this reason, this period can be regarded as the "golden age" for synesthesia research in the nineteenth century. In this time, scientists debated whether synesthesia was a form of pathology or an alternative manifestation of intelligence. The differing roles of heredity and environment were contested, and there were several explanations proposed as to its neural basis. These enquiries went to the heart of the debate as to whether synesthetic experiences are special in any way or, instead, a more vivid manifestation of a more general capacity for forming associations.

The evolution of the concept of synesthesia in the nineteenth century as revealed through the history of its name

“…In 1876, the German psychologist Gustav Theodor Fechner (1801–1887) analyzed color associations mainly for vowels, and collected 442 cases of color associations, but he did not differentiate between synesthetes and nonsynesthetes, and therefore did not use a specific term for synesthesia (Fechner 1876 ; cf. Jewanski et al 2019 , 2–4).…”

Recognizing synesthesia on the international stage: The first scientific symposium on synesthesia (at The International Conference of Physiological Psychology, Paris, 1889)

“…Research on synesthesia also affords insight into nonclinical populations (i.e., how the senses come to be integrated in all people), and it helps us to understand how different brains can perceive reality differently (Simner and Hubbard 2013). During the late twentieth century research on synesthesia increased exponentially (Lovelace 2013), similar to a wave of interest that had emerged in the late nineteenth century (Jewanski 2013;Jewanski et al 2019Jewanski et al , 2020. The first recorded synesthete was Georg Sachs in 1812 (Jewanski, Day, and Ward 2009).…”

“…We do not know who suggested devoting a separate section to "Coloured Audition" (at that time, a synonym for synesthesia; see Jewanski et al 2019), but we can speculate that discussions must have taken place during the conference about creating a new section to deal with it. Two important researchers at that time, Francis Galton and Henry Beaunis (1830Beaunis ( -1921, who also had published about synesthesia before 1889 (for Galton: 1880Galton: , 1881Galton: , 1883; see Burbridge 1994;Jewanski et al 2020;for Beaunis: Beaunis 1881see Nicolas 1995), were members of the patronage committee and may have supported the idea of including synesthesia within the conference, the focus of which was otherwise on hallucinations, hypnotism, heredity, and muscular sensations. These topics were themselves related to contemporary views of synesthesia.…”

“…The aim was to discuss this work at the following conference, and Gruber did attend the second psychological conference, which took place in London in 1892, and gave a presentation in French about L'audition Colorée et les Phénomenes Similairies (Gruber 1892), the only lecture at this congress on synesthesia. Here, he described a schema that showed different connections among the senses (reprinted in Jewanski et al 2020) and reported on his research on letter-color synesthesia, of which he had spoken in Paris.…”

“…In 1893, Flournoy published a monograph on synesthesia that was positively reviewed in different countries by famous psychologists in important journals (e.g., Binet 1894b; Calkins 1893; Cohn 1895; James 1894). This book became a milestone in the history of research on this phenomenon (Claparède 1923;Jewanski et al 2020; Nicolas 2020; Plassart and White 2017).…”