The Expressive Balance Effect: Perception and Physiological Responses of Prosody and Gestures

The ability to deliver a speech effectively and persuade the audience is fundamental in the professional landscape. Nonverbal features, such as voice and gestures, are crucial to improving listeners’ perception and information processing in a public presentation. In nonverbal communication research, most studies have mainly examined the individual effects of these features and not their combined influence. Therefore, this study analyzes the direct and interaction effects of intonation, speech rate, and hand gestures on the speakers’ credibility and effectiveness and the participants’ psychophysiological response (attention and arousal). Results showed that the best combination was a moderate intonation at a medium speech rate with a moderate number of hand gestures. These results supported the so-called Expressive Balance Effect. Speakers must maintain the expressive load of the different nonverbal cues in balance to be more effective and credible and enhance the listeners’ cognitive processing. These findings are helpful recommendations for public speakers.