Domestic Dogs and Human Infants Look More at Happy and Angry Faces Than Sad Faces

Dogs respond to human emotional expressions. However, it is unknown whether dogs can match emotional faces to voices in an intermodal matching task or whether they show preferences for looking at certain emotional facial expressions over others, similar to human infants. We presented 52 domestic dogs and 24 seven-month-old human infants with two different human emotional facial expressions of the same gender simultaneously, while listening to a human voice expressing an emotion that matched one of them. Consistent with most matching studies, neither dogs nor infants looked longer at the matching emotional stimuli, yet dogs and humans demonstrated an identical pattern of looking less at sad faces when paired with happy or angry faces (irrespective of the vocal stimulus), with no preference for happy versus angry faces. Discussion focuses on why dogs and infants might have an aversion to sad faces, or alternatively, heightened interest in angry and happy faces.