People permanence: pet dogs represent their owners when they disappear

We tested pet dogs (Canis familiaris; n=75) for their ability to mentally represent a person who is no longer perceivable. A subject watched and then searched for a person after they hid themselves behind one of two occluders. In the critical test, before being released to search, the subject saw the occluder where the person disappeared move next to an empty occluder. A second experiment then showed the subject the hidden person was no longer behind the original occluder. To successfully find the person, subjects needed to infer that the hidden person had moved behind the second occluder – even though the subject did not directly perceive the switch in locations. Dogs were able to find their owner, when they were the person that was hidden, but only some dogs were able to find an unfamiliar person. Controls ruled out the possibility that dogs simply smelled or heard the hidden person move or that they associated some observable movement with reward. Results support the hypothesis that dogs have secondary representations or “people permanence”, when their owner is invisibly displaced. The performance also suggests the possibility that dogs maintain richer representations of groupmates with whom they are bonded. Future research can test if, after an invisible displacement, dogs primarily represent their owners or if in other contexts they can also represent other social agents and objects.