Thanks for taking me for a ride in the car! Photo credit: Marie T. Russell
Dogs have been part of human social groups for at least 30,000 years. So it’s not unreasonable to suppose that we might have had some influence on their behaviour, and perhaps their understanding, during that time. We certainly know that dogs have developed ways to communicate with us, for example by whining when they are distressed or barking to alert us to intruders.
Many dog owners would probably say their pets can even tell us things using facial expressions, just like humans do. But is that really true? Perhaps they are just showing emotion without meaning to communicate (just like humans also sometimes do). New research published in the journal Scientific Reports suggests it might be, but there are still reasons to be sceptical.
In a rather elegant experiment, the researchers set up four scenarios. They offered a dog food (a guaranteed way to get their interest) while the human handler was facing towards and also away from the dog. They also had the handler face towards and away from the dog without offering food. They found that the animals showed facial expressions more often when the handler was facing towards them than away, regardless of whether or not food was involved.
Until now, there has been little work on whether or not facial expressions in dogs are involuntary. You might be able to see when a dog’s happy, angry or sad from their face, but that doesn’t mean they are purposefully trying to tell you how they felt.
The new paper suggests that the expressions may be a means of communicating something to the person. It is certain that the expression is more frequently displayed when the human is facing towards the dog, even though the handler did not look directly at the dog during the trial, and that humans respond to that expression.
That dogs are able to understand when a person is paying attention to their behaviour is well documented. We also know that dogs show different facial expressions when in the presence of humans, especially in the case of that “guilty” look that every dog owner knows. That particular expression doesn’t actually mean they are feeling guilty. It’s more an attempt to appease the owner who is angry for some, to the dog, unknown reason.
But there are some questions about the particular facial expressions the dogs made in the new study that mean the evidence isn’t conclusive. For example, one of the expressions the authors noticed was the raising of the inner end of the eyebrows. This increases the size of the eyes and makes the dog look more puppy-like.
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Studies have shown that humans prefer animals that look like infants. This explains the popularity of breeds with short noses and large eyes, such as boxers and pugs. Dogs that raise their eyebrows more frequently seem to be more popular with people than those that don’t. This could have led to the breeding of dogs that are more likely to show these more attractive expressions alongside those that have childlike anatomical features.
Another important indicator that the authors noted was when the dogs showed their tongues. Unfortunately, the researchers didn’t separate tongue movements that indicate stress, such as licking the nose or lips, which can be an appeasing signal, from those that indicate pleasure, anticipation or excitement, such as panting or hanging the tongue out of the mouth. Without this distinction it is difficult to draw conclusions about the emotional state of the dogs.
Previous research also suggests that dogs are aware of when a human is paying attention to them and may change their behaviour accordingly. It is possible that these dogs, aware that the human is facing them felt a level of anticipation, excitement and possibly some anxiety which affected their facial expression. The fact that the food produced no extra interest when the person was turned towards the dog or away from them, could be influenced by the fact that the dog was not actually given the food.
The authors suggest that the dog’s facial expressions may be partly a result of their emotional state and partly an attempt to actively communicate with the handler. Without any evidence about the effect of the expression on the behaviour of the handler, it is difficult to say if that is true.
If further research could make distinctions between the type of tongue movements involved in these expressions, as well as the raising of the eyebrows, we might be able to say with more certainty. But whatever the outcome, many dog owners will probably continue to swear their pets are trying to tell them something.
About The Author
Jan Hoole, Lecturer in Biology, Keele University