Sex Differences Influence ERP Components in Semantic Decisions

Background/Objectives: Prediction is a fundamental mechanism of language comprehension, enabling readers to generate expectations about upcoming words during sentence processing. Event-related potentials (ERPs), particularly the N400 and P300, provide sensitive electrophysiological markers of semantic integration and expectancy-related processing. However, the contributions of individual sentence elements to semantic prediction and the influence of sex differences on these processes remain poorly understood. Methods: Forty-six healthy right-handed young adults (23 females) performed a semantic decision task with six-word Spanish sentences ending in congruent or incongruent final words while EEG activity was recorded. ERP components associated with anticipatory and integrative stages of sentence processing were analyzed during the sequential presentation of sentence words. Behavioral performance and sex-related ERP differences were assessed using repeated-measures ANOVAs and correlational analyses. Results: Behavioral findings showed that males committed significantly more errors in detecting semantic incongruities, although overall performance exceeded 92%. Congruent sentence endings elicited a centro-parietal P300, whereas incongruent endings produced a robust N400 followed by a late positive component (LPC). Sex differences emerged, beginning at the third word of the sentence. Males exhibited greater P2 amplitudes and a larger anticipatory P300-like positivity preceding the final word, whereas females showed enhanced N2 and N400 negativities associated with contextual processing and semantic incongruity. Correlations between anticipatory ERP activity and later semantic components supported functional continuity between predictive and integrative stages of language processing. Despite earlier differences, males and females exhibited comparable LPC amplitudes, suggesting convergence during later elaborative processing stages. Conclusions: These findings support predictive models of language comprehension by demonstrating that semantic expectations are progressively constructed throughout sentence processing. Sex-related ERP differences were observed across anticipatory, attentional, and semantic integration stages, indicating quantitative and stage-specific neurophysiological variations rather than qualitatively distinct language-processing strategies.