Four experiments investigated the extent to which judgments of candidate performance in presidential debates could be influenced by the mere knowledge of others’ reactions. In Experiments 1 and 2 participants watched an intact version of a debate or an edited version in which either “soundbite” one-liners or the audience reaction to those soundbites were removed. In Experiment 3 participants saw what was supposedly the reaction of their fellow participants on screen during the debate. Participants in Experiment 4 were exposed to the reactions of live confederates as they watched the last debate of an active presidential campaign. In all studies, audience reactions produced large shifts in participants’ judgments of performance. The results illustrate the power of social context to strongly influence individuals’ judgments of even large amounts of relevant, important information, and they support the categorization of presidential debates as ambiguous stimuli, fertile ground for informational social influence.