Sound characteristics which affect attributes of the synaesthetic visual experience

Abstract

Although research on synaesthesia has blossomed in the last decades, few things are known about inherited sound-colour synaesthesia and processes underlying synaesthetic perception. In this study we investigated how the auditory pitch, the frequency range, the complexity, as well as the structure of the sound affected the synaesthetic visual attributes of chroma, colour brightness, colour plurality and density. A distinct mapping was observed between sound features and visual characteristics, which suggests that visual stimulation requires sensory auditory processing. We propose that congenital synaesthetic perception involves two stages of processing: initially the sensory auditory information is processed by the primary auditory cortex, and then it is distributed to the secondary and extrastriate visual brain areas, generating visual stimulation. This process does not necessarily involve the participation of brain areas responsible for associative thinking.