Individual differences in feedback processing affect perceptual learning

Abstract

The present study examines individual differences in brain responses to feedback stimuli as a complex perceptual task is gradually learned. Event-related potentials were recorded while subjects learned to categorize a visual stimulus that required integration of different physical dimensions. Feedback was provided following the subject's response. High learners achieved about 80% accuracy while low learners remained slightly above chance performance. A feedback-related negativity (FRN) peaking at about 340 ms became less negative-going as the study progressed. This FRN did not however differ between the two groups. On the other hand, the P300, peaking at about 400 was significantly larger following correct feedback for the high than low learners. Importantly, this P300 difference emerged early in learning and was predictive of future performance. The P300 following incorrect feedback increased in amplitude across the study for the high learners but did not change for low learners. A later positivity, peaking at about 625 ms following incorrect feedback was especially large for the high learners when it had a low probability of occurrence, after learning had occurred. The ERP group differences suggest a discrepancy in the utilization of feedback prior to and following learning.