Individual differences in eye movements during skilled reading

Abstract

Despite a large and established literature, studies of eye movements during skilled reading generally assume uniformity at the participant level. However, there is growing evidence that individual differences in reading proficiency among skilled adult readers modulate the early stages of lexical processing. Measures of lexical knowledge have also been shown to be more predictive of differences in eye movement patterns than many word- or sentence-level variables that have traditionally been the focus of research in the field. In five experiments, large samples of skilled readers were assessed on measures of reading and spelling ability in order to test the hypothesis that individual differences in proficiency, and, particularly, the precision of a reader’s lexical representations, modulate eye movements during reading. Gaze-contingent display change paradigms were used to manipulate parafoveal information during sentence reading, tapping the early stages of word identification. The combination of high reading and spelling ability, i.e., lexical expertise, was found to consistently predict both the spatial extent and depth of parafoveal processing. Lexical experts made use of a wider perceptual span and were more likely to extract lexical information from upcoming words than readers with imprecise lexical knowledge. Lexical expertise was also associated with more effective integration of parafoveal and foveal information and more immediate comprehension. These results support the lexical quality hypothesis of reading skill and challenge the assumption that skilled adults all read in essentially the same way. The results also provide insight into the role of parafoveal processing during reading and provide opportunities for the refinement of computational models of eye movement control.