Prior knowledge differentially modulates neural similarity across individuals and events in online physics learning

Prior knowledge is a central determinant of learning, yet how it dynamically influences neural activity during learning remains poorly understood. Here, we examined this question by relating individualized, fine-grained prior-knowledge profiles to neural similarity during online video-based physics learning. At the between-individual level, prior-knowledge-related neural similarity in frontal theta (4-8 Hz) and centro-parietal alpha (8-13 Hz) bands exhibited a non-monotonic relationship with prior knowledge, with greater similarity observed in both high- and low-prior-knowledge learners and lower similarity in intermediate learners. Critically, only frontal theta similarity was positively associated with inter-individual differences in learning outcomes, whereas prior knowledge itself was not directly related. However, within individuals, alpha-band neural similarity at the event level was negatively associated with event-based learning outcomes, but only among learners with low prior knowledge. These findings suggest that the influences of prior knowledge cannot be interpreted uniformly, reflecting in distinct neural similarity patterns across individuals and learning events.