Effective visual field size necessary for vertical reading during Japanese text processing

Abstract

Eye movements were recorded during vertical reading of Japanese text. Saccade length and fixation duration were recorded as a function of moving window size, which varied in length from 1 to 12 characters vertically. Saccade length increased, and fixation duration decreased, as a function of increasing window size. Effective visual field size necessary for vertical reading was found to be approximately 5-6 character spaces in the vertical direction. This span of reading appears to be close to the size during horizontal reading of Japanese text.