This paper examines whether the profusion of ums that so many speakers produce is noticed, and whether these ums influence what audiences think of speakers. Even though ums do not seem to be a product of anxiety or lack of preparation, the first study, using a simple questionnaire, indicated that the average listener assumes that they are. The second study manipulated um rates by editing a tape to create a version where ums were replaced by silence or were eliminated. The original and edited versions were played to audiences who were told to focus on either the content or the style, or were not given any particular instructions. Estimates of ums showed no sensitivity whatsoever in the content focus, some sensitivity without focus instruction, and greatest sensitivity with the style focus, suggesting that ums can be, but are not always, processed automatically. On subjective ratings of the speaker, filled pauses created a better impression than silent pauses, but no pauses proved best of all. The ums had an effect even in conditions where the audience was unable to report their presence.
