The interaction of contextual constraints and parafoveal visual information in reading

An experiment is reported which demonstrates that contextual constraints and parafoveal visual information interact during reading. As subjects read sentences, the parafoveal visual information available from a target area in the sentence was varied: the parafoveal information was either visually similar or dissimilar to a target word the subject would later fixate. The visual similarity of the parafoveal preview was factorially combined with the predictability of the target word based on the preceding sentence context. That is, as the subjects made a saccade to the target area, the parafoveal preview was replaced by either a target word that was highly predictable or one that was relatively less predictable from the sentence context. Eye movements and fixation durations were affected both by the visual similarity of the parafoveal information and the target predictability. Moreover, although the visual similarity of the parafoveal preview produced an effect even when the target was not predictable from the context, the effect of parafoveal information was greater when it was predictable. There was also evidence indicating that when the parafoveal information was highly predictable, subjects appeared to use more detailed parafoveal visual information. The results are interpreted within an interactive framework in which lexical representations accumulate activation via both contextual constraint and parafoveal information.