Same fear responses, less avoidance: Rewards competing with aversive outcomes do not buffer fear acquisition, but attenuate avoidance to accelerate subsequent fear extinction

Abstract

Rewards for approaching a feared stimulus may compete with fear reduction inherent to avoidance and thereby alter fear and avoidance learning. However, the impact of such competing rewards on fear and avoidance acquisition has rarely been investigated. During acquisition, participants chose between one option (CS+ option) associated with a neutral stimulus followed by an aversive unconditioned stimulus (US) and another option (CS− option) associated with another neutral stimulus followed by no US (N = 223 randomized into three groups). In a subsequent test, no more USs occurred. In one group, competing rewards were established by linking the CS+ option to high rewards and the CS− option to low rewards during acquisition and test (Reward Group). In a second group, rewards were present during acquisition, but discontinued during test (Initial-Reward Group). In a third group, rewards were completely absent (No-Reward Group). Without competing rewards, significant avoidance was acquired and persisted in the absence of the US. Competing rewards attenuated avoidance acquisition already after the first experience of the aversive US. Avoidance remained attenuated even when rewards were discontinued during test. Rewards did, however, not change the level of fear responses to the CS+ (US expectancy, skin conductance). Finally, rewards did not change the level of fear reduction during test, which was, however, experienced earlier. Summarized, rewards for approaching aversive events do not buffer fear acquisition, but can prevent avoidance. This damping of avoidance may initiate fear extinction.