Synesthesia and Emotional Sound

Synesthesia gave rise to an important debate in nineteenth-century Europe that was influenced by the Symbolist movement and research into the physiology of perception. Yet, efforts to understand sensory modalities and to pictorially translate musical effects, or vice versa, are very ancient in origin. For example, the ability to coordinate colors and sounds was well known in the ancient cultures of India and China. Similarly, in sixth-century Greece, Pythagoras (570 BC–495 BC) assigned numbers as well as colors to musical notes. There was also interest in how the various sensory modalities were able to reveal the distinctive properties of an object and if these experiences could be translated or shared with others. This chapter examines the foundations of the nineteenth-century debate, the importance of the cultural aspect of synesthesia, and the subsequent search for a neurological explanation. As we show, the lively European debate included Italian, French, English, Swiss, and German scientists who were stimulated to study the relationship between color and sound, music and painting, and the creativity associated with synesthetes. Among the researchers discussed are Carlo Botta (1766–1837), Alfred Vulpian (1826–1887), Filippo Lussana (1820–1897), and Eugene Bleuler (1857–1939). The paper also looks at the three forms of synesthesia related to the debate (metaphoric, constitutional, and pathological) from both historical and contemporary perspectives. Finally, we examine the role of emotion in the various forms of musical synesthesia and possible neuronal well-being.