RECOGNITION OF LIVE HUMAN FACES BY PET DOGS

Several studies have focused on how dogs use visual information about human faces, but their ability to recognize the faces of familiar people is not yet understood. We tested 30 dogs on their ability to recognize their owners by using face information alone. In a series of two-choice tasks, dogs had to choose between their owner and a stranger, who wore identical clothes and stood behind an apparatus that allowed dogs to only see the people’s legs and heads. In the TEST condition heads were not frontally oriented towards the dog and were illuminated by a spotlight, while a shower cap covered the people’s hair. In the BASE condition, heads faced the dog, there was no spotlight and no cap. In the ODOR condition, only legs were visible. A choice was recorded when the dog overstepped the apparatus where one of the two people stood. Only in BASE condition the dogs choose the owner above chance (N = 22, P = 0.008, one-tailed Binomial). Condition had a significant effect on choices (Q = 6.7, P = 0.03), as dogs chose the owner more often in BASE than TEST (N = 14, Q = 5.3, P 0.02) and ODOR (N = 15, Q = 5.4, P 0.02), whereas no difference was found between the latter two (Q = 0.07, P = 0.7). Results suggest that dogs cannot recognize their owner’s face under certain viewing conditions, raising questions about which perceptual information is most relevant for human face recognition by dogs.