Individual differences in lexical decision speed for Chinese single-character words are predicted by ND250 peak...

Reading is a fundamental cognitive skill in modern society that relies on the rapid recognition of visual word forms. Event-related potentials (ERPs) provide a powerful tool for investigating the neural dynamics underlying visual word recognition. Establishing neural-behavior relationships is crucial for characterizing the neural mechanisms underlying specific aspects of behavior. The present study examined whether individual differences in lexical decision speed are associated with the temporal dynamics of the ND250-an ERP component reflecting neural differentiation between real words and pseudowords (or between high- and low-frequency words). Eighty-eight native Chinese readers performed a lexical decision task on real and pseudo Chinese characters while electroencephalographic (EEG) activity was recorded. All real characters used as stimuli were monomorphemic single-character words. Consistent with previous research, pseudo-characters elicited a robust ND250 over occipito-temporal scalp regions, with source estimates localized to the fusiform gyrus. Critically, ND250 peak latency showed a strong positive correlation with reaction times across participants: individuals with earlier ND250 peaks responded faster in the lexical decision task. Hierarchical regression analyses further demonstrated that ND250 latency uniquely predicted lexical decision speed even when earlier (N170) and later (PD300) ERP components were included as predictors. This relationship was consistently observed for both simple and complex characters. Together, these findings suggest that the ND250 serves as an important neurophysiological marker of orthographic processing and represents a key neural mechanism underlying individual differences in the speed of recognizing written words.