The Effects of Reliable Social Feedback on Language Learning: Insights from Electroencephalography 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 (accuracy) and social content. In a forced-choice task, participants learned to associate novel auditory words with known objects and received feedback. There were three types of feedback: Social Reliable (always providing accurate feedback regarding performance), Social Unreliable (providing random feedback: 50% correct and 50% incorrect feedback irrespectively of the performance), and Symbolic Reliable (always accurate feedback). Posttraining behavioral performance was better for words learned with social and symbolic reliable feedback. ERP amplitudes and pupil dilation showed differences as a function of feedback reliability and social content. In the reliable conditions, before feedback, stimulus-preceding negativity amplitude grew as learning progressed, likely due to the expectation of receiving positive feedback. During feedback, late positive complex 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 this showing greater dilation for negative versus 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.