ABSTRACT
Synaesthesia is a condition in which a sensory stimulus not only activates a specific sense—such as when sound waves activate our hearing—but also concurrently, automatically, and involuntarily stimulates another modality (e.g. vision). Music-induced visual mental imagery (VMI) shares some of its features with synaesthesia, the most obvious being that stimulation in one sensory modality co-activates another. In this chapter, we compare both phenomena and, more specifically, carve out differences and commonalities between sound-colour synaesthesia and music-induced VMI. For example, some conceptual and experiential features overlap such as the location of imagined visuals (in the mind’s eye) and the fact that even if synaesthetes cannot control the onset of their synaesthetic experience, some are able to zoom in and out of imagined visuals as are individuals experiencing VMI. A historical comparison reveals that a definition of mental imagery from the 1960s would also fit a definition of synaesthesia as we understand it today. Our main argument is that mental imagery could be considered a weak form of synaesthesia, and we provide several examples and empirical evidence to support this claim. To close the chapter, we compare both phenomena with regard to emotion, memory, and creativity, and extrapolate from current evidence how synaesthetes and non-synaesthetes may behave in experiments concerned with music-induced VMI.
