Eye Movement and Orientation Behaviour during Natural Triadic Conversations: Effects of Noise, Hearing Impairment, and Seating Position

Purpose: Visual information plays a crucial role in supporting speech comprehension and managing turn-taking during conversation. However, how the use of visual cues in everyday interactions changes when auditory information is degraded by background noise or hearing impairment - and how such changes are reflected in gaze behaviour - remains poorly understood.Method: We investigated gaze and head orientation behaviour during natural triadic conversations between familiar interlocutors in a canteen setting. Twelve groups, each comprising one participant with hearing impairment and two with normal hearing, engaged in sixteen four-minute conversations under two background-noise conditions (during and outside lunch hours) and two seating configurations, with interlocutors seated either across from or next to the wearer of mobile eye-tracking glasses. Speech was recorded, and eye movements were tracked for either the participant with hearing impairment or one participant with normal hearing per conversation. Results: Higher noise levels during lunch hours increased gaze towards interlocutors, particularly among participants with hearing impairment. Seating configuration strongly shaped gaze behaviour: interlocutors seated next to the participant being recorded received less direct gaze, and this arrangement elicited increased saccade rate. At turn offsets, talker gaze reliably predicted the next talker, whereas listener gaze was less informative when the upcoming talker was not seated directly in front of them. Conclusions: Under challenging acoustic conditions, gaze remained a robust marker of turn-taking, highlighting its potential relevance for hearing rehabilitation strategies and the development of gaze-informed technologies, such as beamforming hearing aids.