UBC Faculty Research and Publications

The influence of the noradrenergic/stress system on perceptual biases for reward Ehlers, Mana R.; Todd, Rebecca M.; Ross, Colin J.

Abstract

Previous research has established a role for the norepinephrine/stress system in individual differences in biases to attend to reward or punishment. Outstanding questions concern its role in the flexibility with which such biases can be changed. The goal of this pre-registered study was to examine the role of the norepinephrine (NE)/stress systems in the degree to which biases can be trained along the axis of valence in the direction of reward. Participants genotyped for a common deletion variant of ADRA2b (linked to altered NE availability) experienced an acute stress induction or control procedure. Following stress induction, a “bias-probe” task was presented before and after training. In the bias-probe, participants made forced-choice judgments (happy or angry) on emotional faces with varying degrees of ambiguity. For bias training, participants viewed unambiguously angry faces in a task exploiting visual adaptation effects. Results revealed an overall shift from a slightly positive bias in categorizing faces pre training to a more positive bias after training. Carriers of the deletion variant showed overall a more positive bias than non-carriers. Follow-up analyses showed that pre-training bias was a significant predictor of bias change, with those who showed a more negative bias pre-adaptation changing more in a positive direction. Critically, this effect was observed under control but not under stress conditions. These results suggest that the NE/stress system plays an important role in influencing trait-like biases as well as short-term changes in the tendency to perceive ambiguous stimuli as more rewarding than threatening.

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Attribution-NonCommercial-NoDerivatives 4.0 International