Communicating to persuade: the effects of language power and nonverbal immediacy on the efficacy of persuasion

Abstract

The purpose of this study was to examine the impact of powerful speech and nonverbal immediacy on the efficacy of persuasion in a hypothetical sales presentation. Language power and nonverbal immediacy were hypothesized to affect persuasiveness through the potentially powerful nature of both, and to have an interaction effect on persuasiveness. A sample of 211 undergraduate students at a Northwestern University voluntarily completed an online survey, which contained a video clip of a sales presentation. Each participant randomly viewed one of four video clips, which differed in terms of language power (high vs low) and nonverbal immediacy (high vs low). A two way ANOVA indicated that language power had a main effect on the extent of persuasion. However, there was no main effect for nonverbal immediacy, and no interaction effect between language power and nonverbal immediacy. The findings of this study suggested that in a sales presentation, the power of language is an important factor for determining the persuasiveness of a salesperson.