Stress recognition in Mandarin Chinese: exploring auditory baselines and visual modulation using ERP.

This study aimed to determine the perceptual baseline for stress recognition-whether stress recognition relies on an internal baseline computed through online comparison within a sentence or an external baseline accumulated from prior acoustic experience-and to further examine whether this auditory baseline is modulated by the outcomes of internal cognitive processing. To achieve these goals, two event-related potential (ERP) experiments were designed. Experiment 1 employed a passive auditory oddball paradigm to compare ERP responses between unstressed and logically stressed conditions. The results showed that sentence-initial subject logical stress elicited significant P200 modulation before any unstressed syllable appeared in the same trial. The brain accumulates an acoustic template of unstressed speech from prior context and detects logical stress as a deviation from this template, rather than reconstructing the contrast relation within each individual sentence, thus supporting the external baseline hypothesis; Experiment 2 adopted a cross-modal orthographic cuing task, in which written sentences with visual stress marks (bold and underline) were presented simultaneously with their auditory counterparts. The amplitude changes of early auditory components (N100 and P200) under visually congruent and incongruent conditions, and their consistency with the behavioral results, together suggest that visual expectations influence the auditory perception of stress, indicating to some extent that the outcomes of certain internal cognitive processes can affect the auditory baseline for logical stress recognition. These findings contribute to investigating the auditory recognition mechanism of logical stress in Mandarin Chinese sentences.