Modelling Pavlovian biases in depressed and healthy young adults

Pavlovian stimuli signalling potential punishment and reward have powerful effects on instrumental behaviours. For example, a cue associated with punishment will suppress well-learned instrumental responses. However, the degree to which Pavlovian stimuli interfere with the learning of instrumental responses is less well studied. In the current set of studies we investigated the effect of Pavlovian stimuli on instrumental learning and the extent to which depressive symptomatology moderated this relationship. We conducted two experiments using a sample of healthy adults and leveraged computational modelling to estimate learning parameters and the moderating role of depression on these learning parameters. In line with previous literature, participants found it more difficult to learn to make instrumental go and no-go responses in the presence of incongruent cues-for instance, making a "go" response for a cue which signalled punishment, and vice versa. Contrary to expectation we did not observe a reliable relationship between performance and depression scores; while Experiment 1 observed a relationship between depression and model-derived learning rates, these results were not replicated in Experiment 2. We discuss both the theoretical and practical implications of these findings in the General Discussion.