London: The social gazing behaviour of domestic dogs resembles that of humans with the canines viewing facial expressions systematically, preferring eyes, a new study has found.
Researchers at the University of Helsinki in Finland found that the facial expression of dogs alters their viewing behaviour, especially in the face of threat. A total of 31 dogs of 13 different breeds were used in the study.
Prior to the experiment, the dogs were clicker-trained to stay still in front of a monitor without being commanded or restrained. Due to positive training approach, dogs were highly motivated to perform the task.
The study utilised eye gaze tracking to demonstrate how dogs view the emotional expressions of dog and human faces. Dogs looked first at the eye region and generally examined eyes longer than nose or mouth areas.
Species-specific characteristics of certain expressions attracted their attention, for example the mouths of threatening dogs. However, dogs appeared to base their perception of facial expressions on the whole face.
Threatening faces evoked attentional bias, which may be based on an evolutionary adaptive mechanism - the sensitivity to detect and avoid threats represents a survival advantage. Dogs' viewing behaviour was dependent on the depicted species - threatening conspecifics' faces evoked longer looking but threatening human faces instead an avoidance response.
Threatening signals carrying different biological validity are most likely processed via distinctive neurocognitive pathways.
"The tolerant behaviour strategy of dogs towards humans may partially explain the results. Domestication may have equipped dogs with a sensitivity to detect the threat signals of humans and respond them with pronounced appeasement signals," said Sanni Somppi from the University of Helsinki.
This is the first evidence of emotion-related gaze patterns in non-primates.
The findings were published in the journal PLOS ONE.
