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

Visual cues play a crucial role in supporting speech comprehension and managing turn-taking during conversation. However, how the use of these 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. We investigated gaze and orientation strategies during natural triadic conversations between familiar interlocutors in a canteen setting. Twelve groups, each comprising one hearing-impaired and two normal-hearing participants, 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 hearing-impaired participant or one normal-hearing participant per conversation. Higher noise levels during lunch hours increased visual attention towards interlocutors, particularly among hearing-impaired participants. Seating configuration strongly shaped gaze behaviour: side-seated talkers received less direct gaze, and their presence elicited increased visual scanning. At turn offsets, talker gaze reliably predicted the next speaker, whereas listener gaze was less informative when the upcoming talker was not seated directly in front of them. Despite 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.