The influence of word shading and word length on eye movements during reading

Abstract

An interesting issue in reading is how parafoveal information affects saccadic targeting and fixation durations. We investigated the influence of shading selected regions of text on eye movements during reading of long and short words within sentences. A target word, either four- or eight-letters long, was presented in one of four shading conditions: the whole target word shaded; the first half shaded; second half shaded; no shading. There was no evidence of a visually mediated parafoveal-on-foveal effect. Saccadic targeting was modulated by the shading on the first half of the word, such that fixations landed closer to the beginning of the word than in the other three shading conditions. Furthermore, partial word shading, resulting in visual non-uniformity of the target word, produced longer gaze durations than the other conditions. Finally, readers spent more time re-reading target words when they were partially shaded than in the other two conditions. We suggest that our effects are due to targeting of the optimal viewing location and revisits to check words that appear visually unusual. Together, the results indicate robust effects of low-level visual characteristics of the word on oculomotor decisions of where and when to move the eyes during reading.

Keywords:

• Eye movements during reading
• Saliency
• Shading
• Word length
• Non-uniformity

Acknowledgments

The authors would like to thank the two anonymous reviewers for their very helpful comments on this manuscript. The first author acknowledges the support of a joint University of Southampton, School of Psychology, and Biotechnology and Biological Sciences Research Council studentship.

Notes

¹ We recognize that conducting multiple t tests leads to an inflation of the critical alpha level associated with those tests. Ordinarily, we would carry out and report Bonferroni (or other appropriate) corrections for all such tests. However, Bonferroni corrections were too conservative, and, given that our experiment was exploratory, we needed to make a number of comparisons between conditions (necessitating division of the alpha level by 6). For this reason, and in the sense that we wished to report analyses that were maximally informative as to where differences between conditions did and did not lie, we report t test comparisons for landing positions, gaze duration, and second-pass reading times.

² We also carried out analyses of the total number of fixations and total time for the target word, and these analyses showed very similar effects to GD.

³ There was no significant effect of shading on skipping of the target word, F ₁(3, 69) = 1.64, p > .05; F ₂(3, 234) = 1.35, p > .05. Consistent with previous research, there was an effect of target word length on skipping rates, F ₁(1, 23) = 21.79, p < .001, η_p ² = .49; F ₂(1, 78) = 76.02, p < .001, η_p ² = .50. Additionally, there was no interaction between these factors, F ₁(3, 69) = .51, p > .05; F ₂(3, 234) = 0.53, p > .05.

⁴There is an alternative theoretical possibility that we might consider at this point. Given that the parafoveal word is visually distinctive and, arguably, visually salient, we might also have predicted that the point of fixation be attracted to it more rapidly when it was shaded than when it was not. Under such circumstances, we might have found that the fixation prior to the saccade onto the target was actually shorter when the target was shaded than when it was not.