Eyebrow movements as signals of communicative problems in human face-to-face interaction

Repair is a core building block of human communication, allowing us to address problems of understanding in conversation. Past research has uncovered the basic mechanisms by which interactants signal and solve such problems. However, the focus has been on verbal interaction, neglecting the fact that human communication is inherently multimodal. Here, we focus on a visual signal particularly prevalent in signaling problems of understanding: eyebrow frowns and raises. We present a corpus study showing that verbal repair initiations with eyebrow furrows are more likely to be responded to with clarifications as repair solutions, repair initiations that were preceded by eyebrow actions as preliminaries get repaired faster (around 230 ms), and eyebrow furrows alone can be sufficient to occasion clarification. We also present an experiment based on virtual reality technology, revealing that addressees’ eyebrow frowns have a striking effect on speakers’ speech, leading them to produce answers to questions several seconds longer than when not perceiving addressee eyebrow furrows. Together, the findings demonstrate that eyebrow movements play a communicative role in initiating repair in spoken language rather than being merely epiphenomenal. Thus, they should be considered as core coordination devices in human conversational interaction.