The effects of reliable social feedback on language learning: insights from EEG and pupillometry

Language learning is often a social process, and social feedback may play a motivational role. We examined the neurophysiological correlates of word learning with feedback varying in reliability and social content. Participants associated novel auditory words with objects and received social (video clips) or symbolic (static images) feedback. In a forced-choice task, participants learned to associate novel auditory words with known objects and received feedback that was either Social Reliable (correct), Social Unreliable (random), or Symbolic Reliable (correct). Post-training behavioral performance was better for words learned with social and symbolic reliable feedback. Stimulus-preceding negativity (SPN) and late positive complex (LPC) ERP amplitudes, as well as pupil dilation, showed differences as a function of feedback reliability and social content. In the reliable conditions, before feedback, SPN amplitude grew as learning progressed, likely due to the expectation of receiving positive feedback. During feedback, LPC amplitude for positive feedback diminished as learning progressed but not for negative feedback, which was likely consistently used for context updating. These effects were not observed for unreliable feedback, probably because its value was not used for updating information. Pupillometry results corroborated these findings, showing greater dilation for negative vs positive feedback in reliable conditions. Finally, when feedback was social, processing was associated with more frontal activation and behavioral performance was closely correlated with both ERP and pupillometry results. Overall, our findings show differential processing of feedback depending on its informational and social content, advancing our understanding of how social and cognitive processes interact to shape word learning.