Cross-modal association between colour, vowel and lexical tone in nonsynesthetic populations: Cantonese, Mandarin and English

Previous studies suggested that the synesthesia-like coloured hearing could be found in nonsynesthetic population for both vowel quality and pitch. The vowel-colour and pitch-colour associations were investigated separately so it is unclear whether vowel quality or pitch has a stronger effect on crossmodal colour association, and how they may interact. No study has investigated this phenomenon in a tone language in which pitch differences are intrinsically coded with vowel qualities. The current study aims to examine whether there is non-random sound-colour mappings for Cantonese vowels in native and non-native (Mandarin and English) listeners. The results suggested that non-synesthetic subjects showed non-arbitrary vowel-colour associations of Cantonese vowels and pitch played a more fundamental role than vowel quality in coloured-hearing.