Researchers have demonstrated that the presence of people with social preferences has importanteconomic implications. However, the empirical basis of this research relies to a large extent onexperiments that do not provide anonymity between experimenter and subject. It has been arguedthat this lack of experimenter–subject anonymity may create selfish incentives to engage inseemingly other-regarding behavior. If this were the case, these experiments would overestimatethe importance of social preferences. Previous studies provide mixed results and methodologicaldifferences within and across studies make it difficult to isolate the impact of experimenter–subjectanonymity. In this paper we use a novel procedure that allows us to examine the impact of theexact same ceterisparibus variation in anonymity on behavior in three of the most commonly usedgames in the social preference literature. We find that the introduction of experimenter–subjectanonymity has no significant effect in any of the three games.