Letter visual similarity of Japanese hiragana and katakana based on reaction times

Abstract Letter similarity (i.e., perceptual distance) is a critical measure to better understand letter perception and literacy development. Despite its importance, however, measurements of for non-alphabetic scripts are limited, the shortage script interferes with identification universality uniqueness systems across different scripts. In present study, we provide comprehensive matrix Japanese kana letters (hiragana katakana). We obtained discrimination reaction times simultaneously presented pairs calculated distance 4,278 by inversing time. The showed significant correlations previously hiragana katakana. An additional experiment that same sounds (え–エ) produced significantly slower responses compared those (え–コ). However, differences in between sound conditions were smaller than sequentially conditions, suggesting was partially attributable knowledge-based factors (e.g., letter-sound knowledge). This first katakana) will be useful researchers interested