ENHANCED CORTICAL SPEECH TRACKING FOR UNTRUSTWORTHY SPEAKERS

In the present study, we investigated how trust with a communication partner impacts speech perception. Prior work has largely focused on how acoustic and prosodic cues affect perceived trustworthiness, but few studies have examined how previously established trust impacts perceptual processes. We introduced a novel paradigm that systematically established trust and then assessed its impact on cortical speech tracking during story listening.
We used electroencephalography (EEG) to measure neural activity while participants listened to stories spoken by different “gnomes” (voices represented by coloured icons) after familiarising themselves with each voice during an investment-based trust game. The trustworthiness of the gnomes was manipulated by varying how often and how badly they lied during the trust game.
EEG data were analysed using multivariate temporal response functions (mTRFs) to map speech features to neural responses. Cortical tracking of speech features was stronger for gnomes that were untrustworthy compared to trustworthy ones, especially during the first half of each story. This suggests that listeners allocate increased attentional or cognitive resources to untrusted speakers, but this may lessen as additional context is built during listening. We found no evidence that trust affected the temporal dynamics of speech processing, indicating that trust influences the strength of speech tracking, but now how it is tracked.
These findings demonstrate that trust affects speech processing, beyond acoustic or linguistic features. This work highlights the importance of social and cognitive variables in naturalistic speech perception and provides a framework for future research on how listener experience and bias influence communication.