Predictability effects during reading in the absence of parafoveal preview

Abstract

The predictability of upcoming words facilitates both spoken and written language comprehension. One interesting difference between these language modalities is that readers' routinely have access to upcoming words in parafoveal vision while listeners must wait for each fleeting word from a speaker. Despite readers' potential glimpse into the future, it is not clear if and how this bottom-up information aids top-down prediction. The current study manipulated the predictability of target words and their location on a line of text. Targets were located in the middle of the line (preview available) or as the first word on a new line (preview unavailable). This represents an innovative method for manipulating parafoveal preview which utilises return sweeps to deny access to parafoveal preview of target words without the use of invalid previews. The study is the first to demonstrate gaze duration word predictability effects in the absence of parafoveal preview.

Binocular coordination and return-sweep saccades among skilled adult readers

“…Words receiving line-initial fixations are unavailable for parafoveal preprocessing, as they lie outside of the perceptual span, and can only be processed foveally following a return-sweep. Consistent with this, Parker et al (2017) reported longer gaze durations on lineinitial words which could not be preprocessed during a line-final fixation than on words presented midline which were available for parafoveal preprocessing.…”

“…This is very similar to the 28-ms difference that we observed between intraline and accurate line-initial fixations in the current study. Additionally, Parker et al (2017) observed longer gaze durations on line-initial words, where preview cannot be obtained, than on words presented midline, where they could be preprocessed prior to direct fixation. These results add weight to an account of longer lineinitial fixations resulting from a lack of preview.…”

“…Our second analysis which aimed to address Stern's assertion would predict that an increased magnitude of disparity at fixation onset would result in longer lineinitial fixations. However, given previous null effects of the magnitude of disparity on fixation duration (e.g., Kliegl et al, 2006), it is possible that a series of null findings would strengthen alternate claims that longer line-initial fixations result from a lack of preview (Parker et al, 2017) or from planning a series of saccades across the subsequent line (Kuperman et al, 2010).…”

“…However, return-sweeps very infrequently overshoot their target (Hofmeister et al, 1999). Instead, they have a systematic tendency to undershoot the start of the line (Heller, 1982;Hofmeister et al, 1999;Parker, Kirkby, & Slattery, 2017;Parker et al, 2019).…”

Return-sweep saccades during reading in adults and children

“…Because return-sweeps move the eyes a greater distance than other reading saccades, they will be influenced more by this error (McConkie, Kerr, Reddix, & Zola, 1988). This means that return-sweeps will often fall short of their target-the start of a new line-requiring a corrective saccade (Heller, 1982;Hofmeister et al, 1999;Parker, Kirkby, & Slattery, 2017;Rayner, 1998). The likelihood of initiating a corrective saccade increases the further readers land from the left margin (Radach & Heller, 1993).…”