This paper presents results from a modified dictator experiment aimed at distinguishing and quantifying intrinsic motivations for giving. We employ an experimental design with three treatments that vary the recipient (experimenter, charity) and amount passed (fixed, varying). We find giving to the experimenter not to be significantly different from giving to a charity, when the amount the subject donates crowds out the amount donated by the experimenter such that the charity always receives a fixed amount. This result suggests that the latter treatment, first used by Crumpler and Grossman (J Public Econ 92(5–6):1011–1021, 2008), does not provide a clean test of warm glow motivation. We then propose a new method of detecting warm glow motivation based on the idea that in a random-lottery incentive (RLI) scheme, such as the one we employ, warm glow accumulates and this may lead to satiation, whereas purely altruistic motivation does not. We also provide bounds on the magnitudes of warm glow and pure altruism as motives that drive giving in our experiment.