Frequency-based foveal load modulates semantic parafoveal-on-foveal effects

During reading, we can process words allocated to the parafoveal visual region. Our ability to extract parafoveal information is determined by the availability of attentional resources, and by how these are distributed among words in the visual field. According to the foveal load hypothesis, a greater difficulty in processing the foveal word would result in less attentional resources being allocated to the parafoveal word, thereby hindering its processing. However, contradictory results have raised questions about which foveal load manipulations may affect the processing of parafoveal words at different levels. We explored whether the semantic processing of parafoveal words can be modulated by variations in a frequency-based foveal load. When participants read word triads, modulations in the N400 component indicated that, while parafoveal words were semantically processed when foveal load was low, their meaning could not be accessed if the foveal word was more difficult to process. Therefore, a frequency-based foveal load modulates semantic parafoveal processing and a semantic preview manipulation may be a suitable baseline to test the foveal load hypothesis.