Dopamine Enhances Model-Based over Model-Free Choice Behavior

Decision making is often considered to arise out of contributions from a model-free habitual system and a model-based goal-directed system. Here, we investigated the effect of a dopamine manipulation on the degree to which either system contributes to instrumental behavior in a two-stage Markov decision task, which has been shown to discriminate model-free from model-based control. We found increased dopamine levels promote model-based over model-free choice. ► Dopamine increases relative degree of model-based to model-free behavior Decision making arises out of contributions from model-free habitual and model-based goal-directed systems. Wunderlich et al. investigate how dopamine affects each system to contribute to instrumental behavior, finding that increased dopamine levels preferentially promote model-based goal-directed choice.