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

At the first ever worldwide international conference of psychology in Paris, 1889, one symposium included a round-table event devoted entirely to the neurodevelopmental condition of synesthesia. Details of this seminal gathering on synesthesia and its international reception have been lost to historical obscurity. A synesthesia study committee emerged from this meeting, as well as a new research tool. Moreover, the scientific findings discussed during this symposium would be echoed over a hundred years later, when a new wave of synesthesia research in the late-twentieth century arose. This article sheds new light on this seminal gathering and aims to answer the following historical questions: Why was synesthesia included in this conference? What science was discussed? Who were the members of the committee and how did they come to be involved? What were their contributions to synesthesia research before, during, and after the conference? What has history shown us about the impact of this symposium on the science of synesthesia?

The "golden age" of synesthesia inquiry in the late nineteenth century (1876-1895).

Synesthesia is a rare neurological trait that causes unusual, often cross-sensory, 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.

Synesthesia is a rare perceptual condition causing unusual sensations, which are triggered by the stimulation of otherwise unrelated modalities (e.g., the sensation of colors triggered when listening to music). In addition to the name it takes today, the condition has had a wide variety of designations throughout its scientific history. These different names have also been accompanied by shifting boundaries in its definition, and the literature has undergone a considerable process of change in the development of a term for synesthesia, starting with "obscure feeling" in 1772, and ending with the first emergence of the true term "synesthesia" or "synæsthesiæ" in 1892. In this article, we will unpack the complex history of this nomenclature; provide key excerpts from central texts, in often hard-to-locate sources; and translate these early passages and terminologies into English.

The development of a scientific understanding of synesthesia from early case studies (1849-1873).

The first case of synesthesia was reported in 1812 ( Jewanski, Day, & Ward, 2009 ). However, it took almost seven decades before the idea of synesthesia entered the mainstream of science and, subsequently, art. There are no known new cases described between 1812 and 1848, but in the following three decades there are at least 11 reported cases of synesthesia and many reviews of these cases. This comes at an important period in the history of the neurosciences, and for sensory physiology in particular. However, the literature that describes synesthesia during this period is largely unknown to contemporary researchers and historians. The aim of this review is to discuss the reports of synesthesia during this period, providing translations of some key passages, and to place these reports within the contextual framework of nineteenth-century neuroscience.

A colorful albino: the first documented case of synaesthesia, by Georg Tobias Ludwig Sachs in 1812.

In 1812, Georg Sachs published a medical dissertation concerning his own albinism and that of his sister. However, he also goes on to describe another phenomenon--namely synaesthesia involving colors for music and simple sequences (including numbers, days, and letters). Most contemporary researchers of synaesthesia fail to cite the case when offering a history of the subject and fewer still will have read it (the original was published in Latin). In this article, we argue that Sachs's case is the first convincing account of synaesthesia; we provide the first English translation of his description of it; we discuss the influence of the case in early theories about synaesthesia and its resonance with contemporary research findings.