Dog owners show experience-based viewing behaviour in judging dog face approachability.

Our prior visual experience plays a critical role in face perception. We show superior perceptual performance for differentiating conspecific (vs non-conspecific), own-race (vs other-race) and familiar (vs unfamiliar) faces. However, it remains unclear whether our experience with faces of other species would influence our gaze allocation for extracting salient facial information. In this eye-tracking study, we asked both dog owners and non-owners to judge the approachability of human, monkey and dog faces, and systematically compared their behavioural performance and gaze pattern associated with the task. Compared to non-owners, dog owners assessed dog faces with shorter time and fewer fixations, but gave higher approachability ratings. The gaze allocation within local facial features was also modulated by the ownership. The averaged proportion of the fixations and viewing time directed at the dog mouth region were significantly less for the dog owners, and more experienced dog owners tended to look more at the dog eyes, suggesting the adoption of a prior experience-based viewing behaviour for assessing dog approachability. No differences in behavioural performance and gaze pattern were observed between dog owners and non-owners when judging human and monkey faces, implying that the dog owner's experience-based gaze strategy for viewing dog faces was not transferable across faces of other species.