Neurophysiological Markers of Confirmation Bias in Vaccine Information Processing: Fixation-Related Potentials

This study addressed the neurophysiological correlates of confirmation bias in relation to vaccination using data on fixation-related potentials. The laboratory experiment utilized a methodological approach integrating eye tracking and electroencephalography (EEG) to synchronize eye movement data with brain bioelectrical activity. Participants with strong positive or negative attitudes towards COVID-19 vaccination were asked to read texts about vaccination containing positive, negative, and neutral statements, and their responses were recorded in conditions of congruence and incongruence of the valence of the text with the implicit component of attitude measured using the implicit association test. The study results demonstrated significant differences in neurophysiological responses, including increased event-related potential amplitudes in incongruent conditions for the P200, P300, N350, and N400 components. The nature of the response indicates activation of selective attention and enhanced perceptual processing of stimuli (P200), redistribution of attentional resources and the formation of cognitive dissonance (P300), emotional categorization (N350), and semantic, including valence, mismatch (N400). These results emphasize the high sensitivity of the method for identifying the potential associated with gaze fixation with the cognitive and emotional aspects of the perception of information. The methodological approach proposed in this study increases its ecological validity, opening up prospects for investigating implicit cognitive processes in natural conditions of text perception. © 2025 Elsevier B.V., All rights reserved.