The Effect Of Feedback Delay On Outcome Evaluation

Performance-related feedback plays an important role in improving human being's adaptive behavior.Using event-related potentials(ERPs),previous studies have consistently associated the feedback-related negativity(FRN)component with feedback processing after decision making.In addition,subsequent studies used reward positivity(RewP),which was measured by the difference wave between negative feedback and positive feedback,to investigate outcome evaluation processing and found that this component was affected by waiting time before outcome evaluation.Prior research has also suggested that anxious individuals are more prone to detecting threats and susceptible to negative emotions,and show different patterns of brain activity in outcome evaluation.It is quite common that a decision-maker cannot receive feedback immediately;however,few studies have focused on the processing of delayed feedback,especially in subjects who exhibit trait anxiety.Both experiments used the variant of the time estimation task,in experiment 1,we conducted the waiting time,short delay(600-1000ms)and long delay(4000-5000ms),to investigate the effect of feedback delay on anxiety and outcome evaluation.In experiment 2,the we also set the short delay condition(600-1000ms),the difference of the long delay is that the feedback will be presented after five trials,this operation diminished performance-related information,in order to investigate the effect of invalid feedback on reinforcement learning.In experiment 1,we found that in the low trait anxiety(LTA)group,more positive-going RewP was found in the short-delayed than in the long-delayed condition.In contrast,no difference was found in the high trait anxiety(HTA)group.This pattern may reflect the hyperactivity of the reward systems of HTA individuals in uncertain environments(e.g.,the long-delay condition)compared with LTA individuals.Our results provide a direction for future research on the neural mechanisms of reinforcement learning and anxiety.In experiment 2,we adopted the temporospatial principal components analysis(PCA)to separate the Reward Positivity from other ERP components.Results indicated that the Reward Positivity was decreased in the delayed feedback condition,however,no difference of N170 amplitude was found between the two conditions.These results indicate that delayed feedback impaired reinforcement learning process in terms of behavioural adjustment and brain activities.