Eye Guidance and Visual Information Processing

The progressive left-to-right movements of human eyes are demanded by the way that human writing system has developed. This chapter questions whether people make progressive or regressive fixations. “Parafoveal” vision is able to deliver sufficient information to the mechanism that decides the location of the next fixation. Measurement-related and methodological issues discuss the merits and potential problems of oculomotor measures commonly used to index cognitive processes in reading, including fixation probability, single, first and second fixation duration, gaze duration, total viewing duration, and “repair time.” The chapter focuses on three sources. First, the conditions under which a regressive fixation is made, second, the conditions under which word skipping occurs, and third, the variation of the landing position within the next word. Whether semantic information can be collected with extrafoveal vision is represented both in the discussions of reading and in discussions of scene perception. In both cases the data are equivocal.