From holistic to decompositional: Tracking the neural representational shift of Chinese character satiation with representational similarity analysis.

Chinese character satiation is a phenomenon whereby prolonged or repeated inspection induces a compelling subjective experience of structural disintegration. Yet, objective neurophysiological evidence for the proposed mechanism of orthographic decomposition has remained elusive. The present study employed representational similarity analysis (RSA) on electroencephalography (EEG) data to bridge this gap. We first established distinct neural templates for holistic (whole-character judgment) and decompositional (component-judgment) processing. Subsequently, during a satiation phase involving repeated character exposure, we measured how the neural representation's relative similarity to the decompositional versus holistic templates changed between early (low-repetition) and late (high-repetition) trials. Results revealed a significant positive correlation between this objectively measured neural shift and participants' subjective satiation ratings, localized to 620-675 ms post character onset: participants reporting stronger satiation experience exhibited a more pronounced neural representational shift, moving away from the holistic template and toward the decompositional template. These findings provide neurophysiological support for the orthographic decomposition hypothesis for Chinese character satiation, indicating that individual differences in the subjective feeling of disintegration are associated with a measurable reorganization of the underlying neural representation.