Do dogs know what humans know? A study into pet dogs’ (Canis familiaris) ability to attribute knowledge to an unfamiliar person

Domestic dogs demonstrate sensitivity to human gaze and attentiveness, but evidence is mixed for their understanding of human knowledge, in the sense of understanding what a person has or has not seen. Here we tested whether pet dogs take a human competitor's past visual access into account in a 3-choice food competition task. The dogs (N = 22) observed food being hidden under 2 of 3 cups, and witnessed how their human competitor saw only one baiting. When the human chose first, dogs were expected to avoid the cup she had seen baited; when dogs chose first, they were expected to choose randomly between baited cups, or favour the cup both had seen baited. However, the dogs chose randomly between the baited cups, regardless of who had first choice. The dogs did choose the cup only they had seen baited above chance only when the competitor chose first, suggesting a potential preference for this cup only in this situation, but they did not choose this cup more than the cup both had seen. Therefore, the current study provides no clear evidence that pet dogs infer others' knowledge from past visual access. The combination of cognitive steps required to be successful in this task might have been too demanding for the dogs. Alternatively, the competitive setting used may not be as suitable for domestic dogs as it is for other species. Further research in ecologically relevant settings may clarify the extent and limits of dogs' understanding of others' knowledge.