2011 年 30 巻 1 号 p. 141-142
One form of synesthetic perception involves the existence of non-arbitrary mapping between linguistic sounds and visual shapes (the so-called bouba/kiki effect). The mechanisms underlying such synesthetic percepts are unclear. Here we report that this synesthetic association is triggered by phonological activation during normal on-line lexical processing. We designed an implicit interference task in which participants made lexical decisions about Japanese non-words presented in shapes. Consonant sounds of the non-words and the visual shapes were either synesthetically matched or mismatched. The non-words were written in either Japanese phonetic Hiragana script or logographic Kanji script. Generally, phonology is thought to mediate lexical access to Hiragana words but not Kanji words. Our results identified synesthetic associations only with non-words in Hiragana script, suggesting that phonological activation during lexical processing is associated with supra-modal processing.