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60. Cognition and Anhedonia in Depression: The Relation between Rumination and Reward Learning
Rumination and anhedonia are two cardinal features of depression and understanding how they relate to one another is integral to better understand the mechanisms that contribute to this highly disabling disorder. This study sought to investigate the effect of rumination on reward learning by randomly assigning participants to either a rumination or distraction induction and subsequently assessing individuals’ abilities to learn from rewards using the Probabilistic Reward Task (PRT). The variable of interest, response bias (RB), was computed to reflect the extent to which a participant modulates their behavior in response to reinforcement history during the PRT. No significant differences in mean RB were found between the distraction (n=30) and rumination (n=30) conditions (t =.203, p =.840). However, across conditions, trait rumination (RRS) negatively correlated with RB (r = -.306, p = .037), whereas the BDI displayed a non-significant correlation with RB (r = -.228, p > .12.). Moreover, change in RB correlated with RRS even after controlling for mood ratings collected between the induction and PRT (r = -.359, p = .014). These results suggest a relation between rumination and reward learning that may be specific to trait, rather than state, rumination and may operate independently of state mood.