Trait anxiety and probabilistic learning: Behavioral and electrophysiological findings

Anxiety is a negative emotion that affects various aspects of people's daily life. To explain why individuals with high anxiety tend to make suboptimal decisions, we suggest that their learning ability might play an important role. Regarding that anxiety modulates both outcome expectation and attention allocation, it is reasonable to hypothesize that the function of feedback learning should be sensitive to individual level of anxiety. However, previous studies that directly examined this hypothesis were scarce. In this study, forty-two Chinese participants were assigned to a high-trait anxiety (HTA) group or a low-trait anxiety (LTA) group according to their scores in the Trait form of Spielberger's State-Trait Anxiety Inventory (STAI-T). Both groups finished a reward learning task in which two options were associated with different winning probabilities. The event-related potential (ERP) elicited by outcome feedback during the task was recorded and analyzed. Behavioral results revealed that, when the winning probability was 80% for one option and 20% for another, the HTA group chose the 80% winning option less often than the LTA group at the initial stage (i.e., first 20 trials) of the task, but there was no between-group difference in total number of choice. In addition, HTA participants took more time to make decisions in the 80/20 condition than in the 50/50 condition, but this effect was insignificant in the LTA group. ERP results indicated that anxiety affects learning in two ways. First, compared to their LTA counterparts, HTA participants showed a smaller feedback-related negativity (FRN) in response to negative feedback, indicating the impact of anxiety on outcome expectation. Second, HTA participants showed a larger P3 component in the 80/20 condition than in the 50/50 condition, indicating the impact of anxiety on attention allocation. Accordingly, we suggest that individuals' ability of feedback learning could be negatively modulated by anxiety.