The facial expressions of dogs elicit emotional responses in most humans, and now a new research suggests that it's not just because of their natural looks. As it turns out, dogs potentially use their facial expressions in an attempt to communicate with humans.
Most mammals, including humans, exhibit facial expressions that express emotion and behavior. Unlike humans, however, it is believed that the facial expressions of animals are merely involuntary, direct representations of how they are feeling at the moment rather than deliberate responses. This belief has been held even for dogs, whose facial expressions such as the so-called puppy dog eyes elicit empathic responses in humans.
New research shows that the facial expressions of dogs aren't just automatic expressions, but are direct responses to human attention. More than mere emotional displays, the canines' facial expressions are possibly more deliberate attempts to communicate with humans, and are dependent on their audience.
To investigate whether dog responses are deliberate or involuntary, researchers at University of Portsmouth's Dog Cognition Center studied the expressions of 24 family dogs of various breeds. Eleven of the dogs were females, and 13 were males.
The dogs were first given a chance to familiarize themselves with the experiment room as well as the experimenter. Once the experiment began, the dogs were led into a specific spot in the quiet experiment room where the experimenter presented herself in four specific conditions: attentive with food, attentive without food, inattentive (back turned) with food, and inattentive (back turned) without food. Each dog participated in two trials per condition, and each trial was split into sessions to prevent fatigue.
To test the dogs' facial expressions, researchers used dog Facial Action Coding System (FACS) which was first developed for humans. The system analyzes observable facial changes and creates objective and standardized measurements of facial movements.
Researchers found that the dogs produced more facial expressions when someone was watching, and did not produce such reactions to the presence of food alone. Researchers conclude that human attention affects dogs' facial expressions, showing that they are not merely stimulus responses to triggers such as food.
Further, noting that dogs seem to produce more facial expressions and follow the gaze of a human when eye contact has previously been established or when they see the human's eyes, researchers suggest that perhaps the dogs' facial expressions also have communicative purposes.
"We can now be confident that the production of facial expressions made by dogs are dependent on the attention state of their audience and are not just a result of dogs being excited," said Dr. Juliane Kaminski of the University of Portsmouth, lead author of the study.
The study supports previous studies on dogs' sensitivity to humans, such as in a previous study where researchers found that dogs steal more food when the humans' eyes are closed or their backs are turned.
The study was published in Scientific Reports.