According to classical motive disposition theory, individuals differ in their propensity to derive pleasure from affiliative experiences. This propensity is considered a core process underlying the affiliation motive and a pervasive cause of motivated behavior. In this study, we tested these assumptions. We presented participants with positive affiliative stimuli and used electromyography to record changes in facial muscular activity that are indicative of subtle smiling. We were thus able to physiologically measure positive affect following affiliative cues. Individual differences in these affective contingencies were internally consistent and temporally stable. They converged with affiliation motive self- and informant reports and picture story exercise scores, indicating that they are partly accessible to the self, observable to outsiders, and overlap with implicit systems. Finally, they predicted affiliative behavior in terms of situation selection and modification across a wide variety of contexts (i.e., in daily life, the laboratory, and an online social network). These findings corroborate the long-held assumption that affective contingencies represent a motivational core aspect of affiliation.