The acquisition of parafoveal word information in reading

A somewhat counterintuitive finding has emerged from experiments that restrict the "window" of visual information available on a fixation during reading: fixation duration increases even though there is less information to process on a fixation. The two most likely explanations for this phenomenon are: (1) that the reader extracts abnormal information outside the window and this slows down processing; (2) that a restricted window does not allow a preview of a word before it is fixated, and hence identification of the word is slower when the word subsequently is fixated. In the present experiments, these two alternatives were tested. Conditions in which the size of the window alternated between fixations were compared with conditions in which the size of the window remained constant from fixation to fixation. This manipulation allowed us to separate effects due to restriction of the size of the window on the current fixation from preview benefits (which would be due to restriction of the size of the window on the prior fixation). Two experiments demonstrated clear beneficial effects on fixation duration due to receiving a preview of a word on the fixation prior to when it was fixated. In contrast, restriction of the size of the window had only marginal effects on the fixation on which that restriction occurred. In addition, a subsidiary analysis suggested that the benefit of previewing a word was influenced by its length; for short words, a preview primarily allowed the reader to skip the word more frequently, whereas for longer words, a preview primarily shortened the fixation time on the word when it was later fixated.