Interhemispheric integration of number stimuli: comparison of Arabic with Kanji numerals.

Thirty normal subjects were requested to add two numbers which were presented tachistoscopically. Two numbers were displayed either to one visual field or simultaneously one to the left and one to the right visual field. Arabic or Kanji numerals were used. Bilateral presentation was superior to unilateral presentation with both kinds of stimuli. In unilateral presentation, Arabic numbers were processed more proficiently in the left visual field and Kanji numbers in the right visual field.