An ERP study on the certainty of epistemic modality in predictive inference processing

Area of Science:

• Cognitive Neuroscience
• Psycholinguistics
• Neuroscience

Background:

• Psychological studies suggest epistemic modality (EM) certainty directionality affects predictive inference under textual constraints.
• Recent neuroscientific research lacks evidence for this EM certainty function during text reading.

Purpose of the Study:

• To investigate if EM certainty directionality influences predictive inference processing during Chinese text reading.
• To examine the neural underpinnings using electroencephalography (EEG) event-related potentials (ERPs).

Main Methods:

• Manipulated textual constraint and EM certainty (low: "possibly", high: "surely").
• Recorded ERPs from 36 participants during predictive inference tasks.
• Analyzed N400 and late positive component (LPC) effects in different brain regions and time windows.

Main Results:

• Under weak textual constraints, low certainty increased N400 (anticipatory stage), indicating higher cognitive load.
• High certainty elicited a right fronto-central LPC (anticipatory stage) for unexpected words.
• In the integration stage, low certainty showed enhanced N400, while high certainty led to LPC effects related to lexical unpredictability and reanalysis.

Conclusions:

• The findings support the directionality function of EM certainty in predictive inference processing.
• Revealed distinct neural processing patterns for high and low certainty during text comprehension under varying constraints.