Abstract
This study investigated the visual information processing of letters (Japanese characters: Kanas) and numerals. In Experiments 1 and 2, 32 Japanese undergraduate and graduate students participated in a target-classification task. Subjects were required to classify a central target stimulus which was flanked horizontally and symmetrically by two noise stimuli. The reaction time of classifying the target was measured as a function of stimulus type (letters vs. numerals) and noise condition. The results of the two experiments showed the different patterns of noise effects on target classification between letters and numerals. In case of two kinds of Japanese characters: Hiragana and Katakana, the noises influenced stimulus processing stage more than response processing. But on the other hand in case of Arabic and Chinese numerals, the noises influenced only the response processing stage. This finding suggests that the process of identifying letters is different from that of numerals.
