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Considerable evidence suggests that the behavioral mechanisms for instrumental action selection are mediated by two distinct learning processes: a goal-directed process whereby actions are selected with reference to the incentive value and causal relationship between actions and associated outcomes, and a more reflexive habitual process in which actions are elicited by antecedent stimuli without any consideration of the associated outcome. This chapter reviews evidence from experiments in both rodents and humans which suggests that the behavioral dichotomy between these two modes of action selection are also reflected at the neural level, involving at least partly dissociable regions: a circuit involving the medial prefrontal cortex and dorsomedial striatum is implicated in goal-directed learning, whereas a region of posterior lateral dorsal striatum is implicated in habitual learning. Building on the arguments put forward by Winstanley et al. (this volume), it can be concluded that the specific neural circuits identified as contributing to goal-directed learning, but not those involved in habit learning, are a constituent element of the neural systems underlying cognitive search.