Eye movements and the perceptual span in silent and oral reading

Previous research has examined parafoveal processing during silent reading, but little is known about the role of these processes in oral reading. Given that masking parafoveal information slows down silent reading, we asked whether a similar effect also occurs in oral reading. To investigate the role of parafoveal processing in silent and oral reading, we manipulated the parafoveal information available to readers by changing the size of a gaze-contingent moving window. Participants read silently and orally in a one-word window and a three-word window condition as we monitored their eye movements. The lack of parafoveal information slowed reading speed in both oral and silent reading. However, the effects of parafoveal information were larger in silent reading than in oral reading, because of different effects of preview information on both when the eyes move and how often. Parafoveal information benefitted silent reading for faster readers more than for slower readers.