Parafoveal preview benefit in sentence reading: Independent effects of plausibility and orthographic relatedness

Recent evidence from studies using the gaze-contingent boundary paradigm has suggested that parafoveal preview benefit is contingent on the fit between a preview word and the sentence context. We investigated whether this plausibility preview benefit is modulated by preview-target orthographic relatedness. Participants' eye movements were recorded as they read sentences in which the parafoveal preview of a target word was manipulated. The nonidentical previews were plausible or implausible continuations of the sentence and were either orthographic neighbors of the target or unrelated to the target. All first-pass reading measures showed strong plausibility preview benefits. There was also a benefit from preview-target orthographic relatedness across the reading measures. These two preview effects did not interact for any fixation measure. We also found no evidence that the relatedness effect was caused by misperception of an orthographically similar preview as the target word. These data highlight the existence of two independent mechanisms underlying preview effects: a benefit from the contextual fit of the preview word in the sentence, and a benefit from the sublexical overlap between the preview and target words.