Researchers have found that oxytocin causes dogs to take an interest in smiling people's faces. It also made them see angry faces as less threatening. Associated with affection and trust, the hormone oxytocin is likely a key factor in the interaction between dogs and humans.
Researchers showed dogs 43 pictures of smiling and angry faces on a computer screen. Each dog was tested twice:once under the influence of oxytocin, which was administered as part of the test, and once without oxytocin. The dog's gaze on the images and pupil size were measured with an eye tracking device. Emotions and attention direct the gaze and regulate pupil size, making eye tracking a window into the dogs' minds.
Dogs usually focus on the most remarkable aspect of any situation, such as threatening stimuli in a terrifying situation. Recognizing and interpreting threats quickly becomes important for survival. Dogs under the influence of oxytocin were more interested in smiling faces than angry ones. In addition, oxytocin has also influenced the emotional state of the dog, which was evident from their pupil size.
Without oxytocin, the dogs' pupils were widest when they looked at angry faces. This indicated that the angry faces elicited the most powerful emotional response in the dogs. However, under the influence of oxytocin, images of smiling faces improved the dog's emotional state more than that of angry ones. This means that oxytocin probably made the angry faces less threatening and made the smiling faces more attractive.
