Asymmetrical learning and memory for acquired gain versus loss associations.

Neutral stimuli can acquire value when people learn to associate them with positive or negative outcomes (i.e., gain versus loss associations). Acquired value has been shown to affect how gain and loss associated stimuli are attended, remembered, and acted upon. Here we investigate a potential and previously unreported learning asymmetry in the acquisition of gain and loss associations that may have consequences for subsequent cognitive processing. In our first study, we provide meta-analytic evidence that in probabilistic learning tasks that pair neutral stimuli with intermixed win, loss, and no-change outcomes, people learn win-associations better than loss-associations despite the symmetrical task structure and symmetrical outcome probabilities. Then in two empirical studies, we demonstrate that this learning asymmetry is evident when acquiring gain versus loss associations to gray-scale landscape images whether participants earn points or money (Study 2), and whether or not they receive explicit instructions about the outcome contingencies (Study 3). Furthermore, performance on a post-learning source recognition task was also asymmetrical: explicit knowledge of associated outcomes was superior for optimal gain than optimal loss scenes. These findings indicate the acquisition of gain and loss associations need not be equivalent, despite symmetrical outcome probabilities, equivalent numbers of learning trials, and a constant learning criterion. Consequently, learning asymmetries could contribute to valence and optimality differences in subsequent cognitive processing.