Paraverbal Expression of Verbal Irony: Vocal Cues Matter and Facial Cues Even More

Verbal irony is a rhetorical device that is not only verbal but also paraverbal. In the present study, we explored the paraverbal expression of verbal irony which has been largely underinvestigated, especially facial expressions. Given the role played by facial expressions in the detection of emotions, we hypothesized that speakers can communicate irony by facial expression alone. We asked 104 speakers to pronounce the same utterance, sometimes ironically, sometimes not. Naive judges were able to detect which speakers were ironic with increasing accuracy across the following three conditions: prosody only, facial expressions only, and both prosody and facial expressions. We then undertook a systematic description of the utterances, to identify which paraverbal cues induced the highest ironicalness ratings among the judges. Slow speech rate, then expressive movements of the mouth, then eyebrow flashes were the three most influential cues. Overall, facial cues explained more variance than vocal cues. Our results did not support the existence of a single, specific set of paraverbal ironic cues. They did, however, show that speakers routinely produce paraverbal cues, and that these cues, especially facial ones, allow their irony to be detected. The implications for models of irony comprehension are discussed.