Posture and Gestures Can Affect the Prosodic Speaker Impact in a Remote Presentation

Video calls have become a dominant communicative setting, and yet little is known about how nonverbal communication looks like in this setting. Continuing our line of research about nonverbal cues to perceived speaker impact, we examined in this experimental study how gestures are used in video calls, whether a sitting or standing posture alters this use and, in particular, how gestures and posture shape the speaker’s prosody. Eleven Persian native speakers participated in the experiment. The speaking task, i.e. giving a power-point presentation for an (artificial) virtual audience, included three conditions in a within-subjects design: sitting, standing, and standing with stimulated gesturing. We counted communicatively relevant gestures and acoustically analyzed speech prosody in terms of f0, voice-quality, and rhythm parameters. Results show that, without explicit stimulation, speakers do not gesture spontaneously in video-call presentations, independently of posture. However, compared to sitting, standing while presenting creates a significantly different prosody that has the potential to improve the speaker’s impact on his/her audience. This effect is further enhanced when standing speakers are stimulated to gesture while presenting. We discuss our results with respect to the interplay of non-verbal communication behavior and in terms of practical implications for public-speaker training.