Abstract
When I took my first tentative research steps into the fascinating world of synesthesia nearly 20 years ago, there was only one name that crowned the rather scarce field of modern research into the condition: Richard Cytowic. His two groundbreaking books – Synesthesia: A Union of the Senses (1989) and The Man Who Tasted Shapes (1993) – heralded a modern renaissance of interest into the condition. Now, just shy of 30 years after the publication of his first opus, Cytowic offers us an updated and accessible entrée, intended for the discerning palate of both synesthetes and academics who wish to familiarise themselves with this intriguing condition.
More than merely a joining of the senses, Cytowic provides a comprehensive definition of synesthesia as ‘a hereditary condition in which a triggering stimulus evokes the automatic, involuntary, affect-laden, and conscious perception of a sensory or conceptual property that differs from that of the trigger’ (p. 3). While this definition may be a tad on the weighty side, it does illustrate the cognitive as well as perceptual components of synesthetic experiences: a facet often lacking in popular understandings of the condition. But more than merely describing the condition, Cytowic takes great pains to underscore the importance of synesthesia research, noting: ‘synesthesia speaks to the essence of who one is. It celebrates the singularity of the subjective self’ (p. xiv). This affirmation is a leitmotif that reoccurs or is refashioned within each of the subsequent chapters.
In the first chapter – What synesthesia is and isn’t – Cytowic confronts and challenges what he perceives as the orthodox dismissal or denial of what is not immediately explainable, justifying his stance by stating: ‘No amount of brain imaging or psychological analysis can substitute for an introspective report’ (p. 10) – a refreshing standpoint in today’s objective-focused research landscape. Cytowic differentiates between developmental synesthesia (as a neurological condition) and deliberately contrived artistic juxtapositions that aim to mimic synesthetic experiences. His concluding remarks, however, are less clearly delineated, as Cytowic presents the prevailing view of synesthesia as lying along a spectrum; the title of this chapter is thus somewhat superfluous, as the demarcation between what synesthesia is and is not remains inconclusive. Following on from this introductory chapter, Chapter 2 provides a brief history of synesthesia research to date and here again criticises modern science’s continuing rejection of introspection as a reliable experimental technique. Journeying through the technological and theoretical advances of the previous century, Cytowic masterfully encourages readers to consider just how consequential synesthesia is in our quest to understand brain organisation and the mind.
While the first two chapters concern themselves heavily with a description of the core subjective basis of the condition, and a global justification of the value of studying it, the middle chapters are largely concerned with circumscriptive descriptions of specific forms of synesthesia. These chapters do, however, also carry on the more theoretical threads of earlier chapters and delve into issues of objective reality, phenomenology and the study of consciousness. While these diversions are important, they occasionally disrupt the flow of each chapter’s advertised topic area. Nonetheless, the reader is given a comprehensive overview of the research landscape to date and offered tantalising insights into significant future research avenues.
The penultimate chapter examines four types of acquired synesthesia – drug-induced, sensory deprivation and release hallucinations, meditative states and temporal lobe epilepsy – before the book is concluded by an examination of the potential mechanisms of synesthesia. While two main hypotheses are presented, what Cytowic is quick to stress is that no mechanism is ultimately going to be able to answer the ‘why’ of synesthesia, other than to assert that a minority of people are predisposed to it. Synesthesia is thus bookended by theoretical considerations and opportunities for the reader to consider the wider implications of research into this condition.
Appealing to a broader-reaching audience than typical readers of Perception, neurological and psychological concepts are systematically given clear and concise definitions, leaving no room for readers of any academic background to be left by the wayside, which is often the case when reading through material that treats a subject from various discipline-specific angles. What is more, the book is interspersed with large font excerpts from the main text, printed on black pages, that serve to highlight key concepts and catch phrases. These have been chosen to draw the reader’s attention to these concepts and allow for a reflective pause in the lecture of the book. The centrefold pages include vibrant colour illustrations of the included figures: an absolute necessity when treating a subject like synesthesia. More of these illustrations would have made the book more visually appealing, but their limited use is understandable in the context of the highly reasonable retail price (A$20.95), making it an affordable addition to any reader’s personal library.
Cytowic’s latest offering is not just about what synesthesia is but also about what synesthesia means, particularly for questions regarding phenomenology, consciousness, perception and language. This new opus does not provide any substantial value-add for readers who are already familiar with the condition; this is not, however, the intended audience of this book. Indeed, while there are other texts available that provide a more comprehensive and detailed overview of synesthesia (including those by the author), this pocket-sized contribution is a welcome addition to the collection, giving a concise and easily ingested introduction to synesthesia. What Synesthesia does is provide a window into the world of this fascinating condition, and is a book I would strongly recommend for readers unfamiliar with the condition, or for synesthetes in the general population in need of an initial guide to understanding their unique perceptual experiences – and themselves – just that little bit better.