The mere exposure effect refers to the phenomenon in which repeated, unreinforced exposure to a stimulus is sufficient to increase an individual's liking for it. Moreover, numerous experiments have demonstrated that this effect can occur outside of conscious awareness. This article reviews empirical findings highlighting the cognitive factors that enhance the effect, including familiarity, novelty, and consistency of action. The review suggests that the mere exposure effect is closely linked to the social fluency associated with an exposed object. Finally, emerging themes and future directions for research on the mere exposure effect are discussed.