Beneficial influence of in-context predictability when young adults read with a simulated central scotoma

Conflicting results have been reported regarding the effect of word predictability when reading with eccentric vision. The present study aims to shed light on these discrepancies by investigating how in-context word predictability influences reading performance with a simulated scotoma, while considering the visual and lexical features of words. Thirty-five healthy young people read aloud sentences presented using the self-paced reading paradigm. A group of 22 participants practiced reading with a 10° diameter, gaze-contingent simulated central scotoma, with the other group serving as controls. Each participant underwent two in-lab sessions, reading 304 sentences (2-4 hours, depending on their group). Reading time, fixation number, and duration were analyzed for each target word using mixed-effect models. When reading with a simulated scotoma, in-context predictability shows a significant effect on performance, with a 35% decrease in reading time for highly predictable words compared with unpredictable ones (2.5 seconds vs. 1.6 seconds). This effect is modulated by practice, with the decrease dropping to 22% (1.3 seconds vs. 1.0 seconds) after only few hours of scotoma exposure. This effect seems to be driven by the total number of fixations required to identify words and is absent in the control group. These results support the hypothesis that reading with eccentric vision, which limits visual access to text, results in a stronger in-context predictability advantage. Moreover, this effect has a greater impact early in eccentric reading practice. This suggests greater reliance on linguistic inferences to compensate for impaired visual input, compared with central reading, at least until functional adaptation occurs.