We studied the hypothesis that social value orientations are expressed automatically in behavior, as would be suggested by the social intuitionist model. We compared automatic and more deliberated decisions in the dictator game and confirmed that social values determine behavior when responses are based on the intuitive system. By means of both mediation and experimental analyses we further demonstrate that the automatic expression of social value orientations is mediated by perceptions of interpersonal closeness. A reasoning process can subsequently override these automatic responses and disconnect decisions from perceptions of interpersonal closeness. This results in lower levels of other-regarding behavior, at least for prosocials.