This article addresses the relationship between content, voice, and body language in persuasive communication and the contribution of these three elements of persuasive performances to its overall persuasiveness. Findings are presented from two separate laboratory experiments. In the first experiment three versions of a video displaying a speech were shown to three different groups of participants: without vocal emphasis and without gestures of the speaker, with vocal emphasis but without gestures, with vocal emphasis and gestures. Audio tracks of the first (...) two experimental conditions were later used in the second experiment to analyze the effects of vocal emphasis when no visual cues are present. Measurement included a questionnaire as well as Real Time Response-measurement. It was found that content dominates the effect of the speech; emphasis and gestures, however, improved the perception of some features of the speech, such as liveliness and power. Audio-only versions yielded similar results but were rated more favorably in general. (shrink)