Nonverbal cues are important elements of persuasive communication whose influence in political debates are receiving renewed attention. Recent advances in political debate research have been driven by biologically grounded explanations of behavior that draw on evolutionary theory and view televised debates as contests for social dominance. The application of biobehavioral coding to televised presidential debates opens new vistas for investigating this time-honored campaign tradition by introducing a systematic and readily replicated analytical framework for documenting the unspoken signals that are a continuous feature of competitive candidate encounters. As research utilizing biobehavioral measures of presidential debates and other political communication progresses, studies are becoming increasingly characterized by the use of multiple methodologies and merging of disparate data into combined systems of coding that support predictive modeling.
Key elements of nonverbal persuasion include candidate appearance, communication style and behavior, as well as gender dynamics that regulate candidate interactions. Together, the use of facial expressions, voice tone, and bodily gestures form uniquely identifiable display repertoires that candidates perform within televised debate settings. Also at play are social and political norms that govern candidate encounters. From an evaluative standpoint, the visual equivalent of a verbal gaffe is the commission of a nonverbal expectancy violation, which draws viewer attention and interferes with information intake. Through second screens, viewers are able to register their reactions to candidate behavior in real time, and merging biobehavioral and social media approaches to debate effects is showing how such activity can be used as an outcome measure to assess the efficacy of candidate nonverbal communication during televised presidential debates.
Methodological approaches employed to investigate nonverbal cues in presidential debates have expanded well beyond the time-honored technique of content analysis to include lab experiments, focus groups, continuous response measurement, eye tracking, vocalic analysis, biobehavioral coding, and use of the Facial Action Coding System to document the muscle movements that comprise leader expressions. Given the tradeoffs and myriad considerations involved in analyzing nonverbal cues, critical issues in measurement and methodology must be addressed when conducting research in this evolving area. With automated coding of nonverbal behavior just around the corner, future research should be designed to take advantage of the growing number of methodological advances in this rapidly evolving area of political communication research.