Roundness-sharpness rating and analysis of Japanese Hiragana characters in Japanese-speaking, Japanese hearing-impaired, and English-speaking adults

Abstract

Given recent evidence that the visual shape of alphabetic characters such as “B” and “K” influences the bouba/kiki effect (Cuskley et al., 2017), it is interesting to rate and analyze the roundness-sharpness of characters in other languages. To address this issue, the present study experimentally rated the roundness-sharpness of Japanese Hiragana characters using Japanese-speaking, Japanese hearing-impaired, and English-speaking adults. The results showed significantly high correlations of roundness-sharpness ratings between all groups of participants, suggesting that in Japanese, character roundness-sharpness ratings are stable regardless of the amount of auditory input in Japanese. Moreover, in order to examine the roundness-sharpness of characters corresponded to nonsense words in previous bouba/kiki experiments, we analyzed the effects of consonants ([m], [n], [r] vs. [k], [t], [s]) and vowels ([u], [o] vs. [i], [e]) on character roundnesssharpness ratings. The participants of all groups showed significantly rounder ratings toward characters that corresponded to round related sounds ([m], [n], [r], [u], [o]) than sharp related sounds ([k], [t], [s], [i], [e]). These findings suggest a correspondence between the visual shape of characters and the visual figures of previous bouba/kiki experiments in terms of roundness-sharpness.