Language, at its core, is a social act. The present investigation sought to examine the influence of interpersonal context on filler use (um, uh) while answering factual questions. Experiments 1 and 2 investigated differences in computer versus human interaction. As predicted, more fillers were uttered when interacting with a human than with a computer. Experiment 3 sought to examine a self-presentational view of filler use, whereby the mere presence of another human should increase ones use of fillers. Consistent with a self-presentational account, mere presence of the experimenter elicited more fillers than when the experimenter was absent. A cross experimental analysis revealed that while mere presence increases filler production, the need for interpersonal coordination increases filler use above and beyond mere presence. These results are consistent with at least two views of filler function: (1) fillers are used to save face and (2) fillers are used to coordinate interpersonal interactions.