DISSOCIATING CONGRUENCE EFFECT IN LETTERS VERSUS SHAPES: THE CASE OF KANJI AND KANA IN JAPANESE
Alphabet letters and non-letter shapes are dissociated at the early visual processing stage, which was demonstrated by positive congruence effect for non-letters and negative congruence effect for letters. The present study reviewed attempts extending those findings into other orthographic system, kanji and kana in Japanese. Letters and pseudo-letters were targets in a choice-response task. Targets were presented in isolation or surrounded by congruent or incongruent shapes. Congruence effects were obtained for letters and pseudo-letters when response categories were distinguished by targetâ€™s shape. When targets were distinguished by their content (letters or pseudo-letters) or individual items, congruence effects were still observed for pseudo-letters but no longer for letters. Such a task-specific dissociation in effect is in accordance with previous observations for alphabet. In addition, dissociation between letters and non-letters was stronger in kanji than in kana. Implications for letter perception are discussed.