Probabilistic adaptation of language comprehension for individual speakers: evidence from neural oscillations

TL;DR

This study demonstrates that listeners probabilistically adapt language comprehension based on speaker stereotypes, with neural oscillations indicating both general and speaker-specific adjustments in expectations during social language processing.

Contribution

The paper introduces neural evidence for two distinct mechanisms of social stereotype adaptation in language comprehension, linked to high-beta and theta oscillations.

Findings

High-beta oscillations reflect general expectation adjustments to stereotype violations.

Theta oscillations vary with individual openness, indicating personal differences in stereotype processing.

Only high-beta effects persisted when dissociating speaker identity from stereotype frequency.

Abstract

Listeners adapt language comprehension based on their mental representations of speakers, but how these representations are updated remains unclear. We investigated whether listeners probabilistically adapt comprehension based on the frequency of speakers making stereotype-incongruent statements. In two EEG experiments, participants heard speakers make stereotype-congruent or incongruent statements, with incongruency base rate manipulated. In Experiment 1, stereotype-incongruent statements decreased high-beta (21-30 Hz) and theta (4-6 Hz) oscillatory power in the low base rate condition but increased it in the high base rate condition. The theta effect varied with listeners' openness trait: less open-minded participants tended to show theta increases to stereotype incongruencies, while more open-minded participants tended to show theta decreases. In Experiment 2, we dissociated incongruency base rate from the target speaker by manipulating it using a non-target speaker and found that only the high-beta effect persisted. Our findings reveal two potential mechanisms: a speaker-general mechanism (indicated by high-beta oscillations) that adjusts overall expectations about hearing statements that violate social stereotypes, and a speaker-specific mechanism (indicated by theta oscillations) that updates a more detailed mental model specifically about an individual speaker. These findings provide evidence for how language processing interacts with social cognition.