Synaesthesia: an overview of contemporary findings and controversies.

Research on synaesthesia is undergoing something of a renaissance, having initially been a hot topic in psychology and philosophy in the late 19th and early 20th centuries. One hundred years ago investigators failed to define an objective framework within which to characterise the phenomenon, and so interest in the topic waned. With the cognitive revolution and the rapid rise of new experimental techniques in human neuroscience, interest in synaesthesia as a legitimate topic for scientific investigation has been rekindled. Since the 1980s there has been rapid growth in scientific and media interest in synaesthesia, and there is now a sense that real progress is being made. This Special Issue of Cortex brings together the largest collection of empirical papers on the topic of synaesthesia to date. The 21 papers collected herein showcase the many significant advances that have been made in understanding the behavioural and neural bases of synaesthesia. The contributions reflect the work of more than 60 investigators from nine different countries. We are confident that the papers presented in this Special Issue will set the agenda for synaesthesia research for many years to come.