Dogs’ eye movements and pupil dilation do not show sensitivity to differing intentions underlying third-party interactions (advance online)

The ability to interpret others’ actions in terms of underlying intentions, rather than just perceiving them as continuous streams of bodily movements, allows us to make sense of the social world around us. Despite many years of research, it is still unclear to what extent this ability is shared with non-human species. In an eye-tracking study (N = 40), we asked whether dogs’ (Canis familiaris) eye-movements and pupil sizes would show an implicit reaction to an ambiguous as opposed to a clear action. In the video stimuli, a human actress either held a dog’s snout closed (ambiguous action) or petted the dog’s snout (clear, more familiar action). We found no significant evidence that dogs’ eye-movements and pupil sizes differentiated between these conceptually different, but perceptually similar, actions. We discuss possible cognitive differences between dogs’ and humans’ visual processing of third-party social interactions as well as limitations of the present study