It is challenging to accurately trace the origins of synesthesia, a neurological condition where the stimulation of one sense triggers a response in another. The first documentation appeared in a Bavarian medical student’s dissertation in 1812, which included associations of colors with musical tones and letters. UC Berkeley French Professor Liesl Yamaguchi remarks, “He enumerates the colors he sees in connection with the letters of the alphabet. A and E: vermilion, I: white, O: orange and so forth.”

In her new book "On the Colors of Vowels: Thinking Through Synesthesia," Professor Yamaguchi explores the emergence of synesthesia in the 19th century, a period when it began to be more thoroughly examined despite its likely ancient roots. She explains that this phenomenon might have been recognized as far back as Ancient Greece, altering its modern implications and understanding.

Book Chat event attendees can join Yamaguchi on April 9 at UC Berkeley, where she will discuss how humanities scholars uniquely investigate synesthesia, which hard sciences cannot methodologically achieve. According to Yamaguchi, synesthesia can involve experiencing colors linked to musical sounds or linguistic elements such as graphemes, phonemes, words, and numbers. There are varied forms of synesthesia, reflecting a broader interpretation of sensory experiences.

The term "synesthesia" was absent in the 1812 Sachs dissertation but is retrospectively associated with the concept. Yamaguchi notes that "people have probably been sensing this way for as long as people have existed." The Victorian social scientist Francis Galton made significant strides by publishing early visualizations of synesthesia in 1883.

Yamaguchi tackles the risk of literal versus metaphorical readings within her work. She explores experimental psychology, phonetics, and poetics, often tasked with determining the intersection of visualization and sensory perception—"When someone describes a vowel as 'bright,' it is often impossible to know if they mean that it has a relationship to luminosity or that it has a certain sound."

She argues that modern science significantly reframed synesthesia as a testable and respectable subject of study in the 20th century, shifting it from a perception "stigmatized for most of the 19th century” to an indicator of creativity. Yamaguchi this, noting a "very triumphant moment for synesthesia advocates" with the advent of technology validating the condition.

While modern science now has a more flexible approach to studying synesthesia, allowing convergence with humanistic studies, Yamaguchi emphasizes the complexity, noting that language describing sensory perceptions is deeply revealing.