Animals approach rewards and cues associated with reward, even when this behavior is irrelevant or detrimental to the attainment of these rewards. Motivated by these findings we study the biology of financially-costly approach behavior in humans. Our subjects passively learned to predict the occurrence of erotic rewards. We show that neuronal responses in ventral striatum during this Pavlovian learning task stably predict an individual's general tendency towards financially-costly approach behavior in an active choice task several months later. Our data suggest that approach behavior may prevent some individuals from acting in their own interests.