To clarify the human mechanism that controls the relation between information processing and eye movements, we propose a fixation masking method that detects fixations and masks only those fixations. This paper describes how we examined the time required to obtain information on Japanese characters as well as the quantity of information acquired at each fixation point. Subjects were instructed to recognize incorrect characters from text they read. The results indicated that at least 67 ms were required to obtain visual information after viewing the stimulus. However, the masking affected the character recognition process in brain. From the distribution of fixation duration, approximately 130 ms were required to invoke the saccade once the subject had perceived the mask. Our results were different from Rayner's results. We assume that more complex information processing is required to read Japanese than to read English.
