Synaesthesia in Chinese characters: The role of radical function and position

•We present evidence for synaesthesia in a logographic language – Chinese.•We show that Chinese characters can be coloured by their constituent morphological units – radicals.•We show that radicals are influential both by their function and position in a character.•We found that characters tend to be synaesthetically darker and bolder than their component radicals.

Grapheme-colour synaesthetes experience unusual colour percepts when they encounter letters and/or digits. Studies of English-speaking grapheme-colour synaesthetes have shown that synaesthetic colours are sometimes triggered by rule-based linguistic mechanisms (e.g., B might be blue). In contrast, little is known about synaesthesia in logographic languages such as Chinese. The current study shows the mechanisms by which synaesthetic speakers of Chinese colour their language. One hypothesis is that Chinese characters might be coloured by their constituent morphological units, known as radicals, and we tested this by eliciting synaesthetic colours for characters while manipulating features of the radicals within them. We found that both the function (semantic vs. phonetic) and position (left vs. right) of radicals influence the nature of the synaesthetic colour generated. Our data show that in Chinese, as in English, synaesthetic colours are influenced by systematic rules, rather than by random associations, and that these rules are based on existing psycholinguistic mechanisms of language processing.