Visual perspective taking by dogs (Canis familiaris) in a Guesser-Knower task: evidence for a canine theory of mind?

We tested domestic dogs (N = 16) in a Guesser-Knower task in which they chose between possible locations for hidden food indicated by human informants. In four experiments, the perceptual access of the Guesser and Knower to the hidden food baiting was manipulated. When informants had differing perceptual access to the baiting, dogs preferred the location indicated by the Knower from the start of testing (Experiment 1), even when baiting was done by a third experimenter (Experiments 2-3). However, when there was no difference in perceptual access and both informants either knew or did not know the food location, dogs had no preference between the informants (Experiment 4). Controls ruled out alternative explanations in terms of associative learning, unintentional and olfactory cues. Analysis of individual data showed no significant heterogeneity across dogs, and results were not correlated with age or sex. Dogs' performances were superior to those of nonhuman primates in previous studies. Although a mentalistic explanation is not required, results add to evidence that dogs have a remarkable sensitivity to cues related to humans' attentional state, which enables them to respond as if they had a functional theory of mind in the Guesser-Knower task with human informants.