Posted Date: December 7, 2017
Research on dogs' response to human emotional expressions.
A new study published in the January 2018 edition of the journal Behavioural Processes describes a research project involving 17 adult dogs with good health and temperaments. The dogs' age range was two to seven-and-a-half years old and there were nine males, eight females and a variety of breeds.
Each dog was individually presented with a set of black and white photographs. The photos featured dogs and humans that were strangers to the dogs with several different facial expressions based on emotions such as anger and happiness. At the same time, a sound was played from each photo subject that mirrored the emotional state of the photo, or sometimes a neutral sound was played. The researchers looked at two responses from the dog - whether they looked at, or away, from the screen and if they displayed mouth-licking.
No food was presented during the study to eliminate the possibility that any mouth-licking behaviors were food-related.
The researchers found that dogs shown a picture of a negative expression (i.e. anger) engaged in mouth-licking far more frequently then when shown a positive expression. This behavior did not appear to be dependent at all on the auditory data and also was not found to be strong in response to the photos of the other dogs. The mouth-licking behavior is suggested by the researchers to be more than just a stress response but a "functional response" to negative stimuli - in other words a response involving physiological changes such as an increase in blood flow and heart rate.
The dogs' responses also indicate that they may be able to perceive negative emotional states of humans simply by looking at their faces. The researchers state, "The subjects' perception of negative facial expressions appear to have activated a cognitive representation of a negative emotion category...which potentially led to an affective response resulting in the display of this [mouth licking] behaviour. This relationship between cognitive and other affective responses is consistent with dogs having a functional understanding of emotionally charged expressions."
We all know it's important to recognize signs of stress when training and competing with dogs to facilitate learning and a positive experience for the dog. This study would indicate it's particularly important to always be cognizant of how our facial expressions, even unintentionally, may be affecting our dogs' emotional state which can lead to less effective training and performance.