In multiparty systems, parties signal conflict through communication, yet standard approaches to measuring partisan conflict in communication consider only the verbal dimension. We expand the study of partisan conflict to the nonverbal dimension by developing a measure of conflict signaling based on variation in a speaker’s expressed emotional arousal, as indicated by changes in vocal pitch. We demonstrate our approach using comprehensive audio data from parliamentary debates in Denmark spanning more than two decades. We find that arousal reflects prevailing patterns of partisan polarization and predicts subsequent legislative behavior. Moreover, we show that consistent with a strategic model of behavior, arousal tracks the electoral and policy incentives faced by legislators. All results persist when we account for the verbal content of speech. By documenting a novel dimension of elite communication of partisan conflict and providing evidence for the strategic use of nonverbal signals, our findings deepen our understanding of the nature of elite partisan communication.
