Temporal dynamics of perceptual integrity and semantic congruency during color-word processing: An ERP and decoding study

Visual word recognition involves both perceptual and semantic processes, yet how both factors interact during early and late stages of neural processing remains unclear. In this study, we employed event-related potentials (ERPs) and multivariate pattern analysis (MVPA; decoding) to investigate the temporal dynamics of color-word congruency (congruent vs. incongruent) and font completeness (complete vs. incomplete) in a modified Stroop experiment. 26 participants (13 males; aged 19-28 years old; M = 21.8, SD = 2.5) viewed Chinese color words presented in either matching or mismatching font color, with font forms being either intact or degraded. The ERP results revealed that N170 amplitudes were significantly influenced by font integrity and marginally by color congruency, with a notable interaction between the two factors. Additionally, N2 amplitudes showed a significant main effect of font integrity only. P3 amplitudes were modulated by both factors independently, without interaction, while LPP responses were significantly affected only by color congruency. MVPA results further demonstrated that font integrity could be decoded from around 150 to 600 ms, while color congruency could be decoded reliably from approximately 360 to 800 ms. Moreover, the decoding analysis did not reveal an interaction similar to that observed in the ERP results between congruent and incongruent conditions across different perceptual contexts. These findings support a two-stage processing model, in which early perceptual features are processed prior to semantic congruency integration. The combination of ERP and MVPA highlights the distinct temporal profiles underlying perceptual and semantic processing in visual word recognition.