ASYNCHRONY OF LATERAL ONSET AS A FACTOR IN DIFFERENCE IN VISUAL-FIELD

An experiment in matching judgments was designed to examine a role of perceptual process in apparent asymmetry in 20 humans. Recognition of Hirakana letters (Japanese letters) was required. The experimental condition in which stimuli were presented to the left visual field first and to the right visual field second, produced more errors for all stimulus intervals (0-60 ms) than experimental conditions where stimuli were presented to the right visual field first and to the left 1 s. Especially, superiority of the latter condition was marked with the longest stimulus interval employed. Superiority of the left hemisphere function for recognizing Hirakana leters was indicated and suggested that memory and perceptual process contribute to this laterality effect.