Contains fulltext : 90046.pdf (publisher's version ) (Open Access)Background - Psychopathy (PP) is associated with a performance deficit in a variety of stimulus-response and stimulus-reinforcement learning paradigms. We tested the hypothesis that failures in error monitoring underlie these learning deficits. Method - We measured electrophysiological correlates of error monitoring [error-related negativity (ERN)] during a probabilistic learning task in individuals with PP (n=13) and healthy matched control subjects (n=18). The task consisted of three graded learning conditions in which the amount of learning was manipulated by varying the degree to which the response was predictive of the value of the feedback (50, 80 and ...