Synesthesia: An experience of the third kind?

Abstract

What is it like to have a synesthetic experience? Most synesthetes have stressed “having trouble putting into words some of the things (they) experience” as if they had to explain “red to a blind person or middle-C to a deaf person”. The current definition of synesthesia as a condition in which “stimulation in one sensory or cognitive stream leads to associated experiences in a second, unstimulated stream” leaves the question open: What do these ‘associated experiences’ consist in? Over a good part of my scientific career, I’ve spent much time and energy chasing down an elusive creature known as synesthesia. Early in this quest, I thought I’d caught up with it: I was poised, ready to snare it - only to watch it get away. Apparently, my first synesthesia-catcher was too small, and insufficiently flexible, to capture a critter at once so large and agile. (Marks 2011, p. 47)