Fixation-Related Potentials Reveal Multiple Effects of Context across the Visual Field in Natural Reading

Poster Session B - Sunday, April 14, 2024, 8:00 – 10:00 am EDT, Sheraton Hall ABC

Allyson Copeland¹ (allyson.copeland@psych.utah.edu), Julian Poletti¹, Brennan Payne¹; ¹University of Utah

During reading, it is unclear how and when central attention gets allocated across the visual field to extract and integrate semantic features of words. The co-registration of eye-movements with electroencephalography (EEG) allows for the estimation of fixation-related brain potentials (FRPs) in ecologically-valid visual tasks, including reading. While FRP studies have begun to chart the time-course of semantic processing, for example showing N400 modulations by plausibility and predictability, no studies have simultaneously examined anterior (linked to predictive processing) and posterior (linked to semantic integrations) post-N400 positivities in natural reading. We recorded simultaneous eye movements and EEG while participants read constraining sentences with expected, unexpected (but plausible), and anomalous target words (e.g., When the power went out the house became dark/cold/half like last time). When time-locking fixations to the pre-target word, we observed a parafoveal N400 that was largest to anomalous words, followed by unexpected, and then expected words. The N400 was facilitated when the word was subsequently fixated, suggesting trans-saccadic integration of semantic features. At target fixation, we also observed a late anteriorly distributed positivity to unexpected target words, an effect that was not present at the pre-target word. Lastly, we observed a late posteriorly-distributed positive component that was stronger when time-locked to the pre-target word compared to the target word, suggesting that some integrative processes may begin in parafoveal vision in natural reading. Collectively, these findings suggest that readers can begin accessing semantic information in parafoveal vision, but that higher-level semantic processing requires the orchestration of parafoveal and foveal representations.

Topic Area: LANGUAGE: Semantic