The original article:
How dogs scan familiar and inverted faces: an eye movement study
Sanni Somppi, Heini Törnqvist,Laura Hänninen,Christina M. Krause,Outi Vainio
http://link.springer.com/article/10.1007/s10071-013-0713-0/fulltext.html
Facial recognition is an important skill for humans and other social animals. Humans have specific brain mechanisms involved in face processing, which focuses attention to faces and recognizes the identity of faces remarkably quickly and accurately. However, the face recognition mechanisms of dogs are weakly understood. Professor Outi Vainio’s research group from the University of Helsinki studied how dogs look at facial images by using eye movement tracking. The results show that dogs are able to recognize faces in the pictures; dogs focus their attention especially on the eye area and look at familiar faces more often than strange ones. The article was published on 5 December 2013 on the scientific journal Animal Cognition.
Faces play an important role in communication and identity recognition in social animals. Domestic dogs often respond to human facial cues, but their face processing is weakly understood. In this study, facial inversion effect (deficits in face processing when the image is turned upside down) and responses to personal familiarity were tested using eye movement tracking. A total of 23 pet dogs and eight kennel dogs were compared to establish the effects of life experiences on their scanning behavior. All dogs preferred conspecific faces and showed great interest in the eye area, suggesting that they perceived images representing faces. Dogs fixated at the upright faces as long as the inverted faces, but the eye area of upright faces gathered longer total duration and greater relative fixation duration than the eye area of inverted stimuli, regardless of the species (dog or human) shown in the image. Personally, familiar faces and eyes attracted more fixations than the strange ones, suggesting that dogs are likely to recognize conspecific and human faces in photographs. The results imply that face scanning in dogs is guided not only by the physical properties of images, but also by semantic factors. In conclusion, in a free-viewing task, dogs seem to target their fixations at naturally salient and familiar items. Facial images were generally more attractive for pet dogs than kennel dogs, but living environment did not affect conspecific preference or inversion and familiarity responses, suggesting that the basic mechanisms of face processing in dogs could be hardwired or might develop under limited exposure.