Visual word form familiarity and attention in lateral difference during processing Japanese Kana words

The purpose of this study was to examine the relationship between familiarity and laterality in reading Japanese Kana words. In two divided-visual-field experiments, three- or four-character Hiragana or Katakana words were presented in both familiar and unfamiliar scripts, to which subjects performed lexical decisions. Experiment 1, using three stimulus durations (40, 100, 160 ms), suggested that only in the unfamiliar script condition was increased stimulus presentation time differently affected in each visual field. To examine this lateral difference during the processing of unfamiliar scripts as related to attentional laterality, a concurrent auditory shadowing task was added in Experiment 2. The results suggested that processing words in an unfamiliar script requires attention, which could be left-hemisphere lateralized, while orthographically familiar kana words can be processed automatically on the basis of their word-level orthographic representations or visual word form.