- An active stream of facial expressions is part of the normal communication process between humans.
- A still and unresponsive face causes a negative reaction for young human children.
- Dogs don't like to continue interacting with a person whose facial response is unchanging and unresponsive.
A lot of research shows that dogs look at our faces and read our emotions from our expressions. Some new research suggests that a passive, unchanging human face (think "poker face") is interpreted by dogs as a negative expression, and dogs respond accordingly.
Dogs Don't Love Statues
I am reminded of a woman that I once knew who complained to me, "Dogs just don't seem to like me." I reassured her that was unlikely, unless she was sending negative emotional signals to the dog. To demonstrate this, I brought out my Cavalier King Charles Spaniel, Ripley, who was extremely affectionate and worked for half his life as a therapy dog. Ripley normally approached anybody with a great show of friendliness. The woman sat stiffly in her chair with no expression of emotion on her face whatsoever, and I was surprised to see that, instead of his normal approach behavior, Ripley's tail drooped; he lowered his body a bit and stood a distance away from her. I was puzzled by his failure to show any affection in this instance, since she was not displaying anger or fear, but simply sitting like a statue.
The interpretation of Ripley's behavior has recently become clear to me based on data from a report coming out of the laboratory of Mariana Bentosela at the Faculty of Medicine at the University of Buenos Aires in Argentina.
When we are trying to communicate with someone, the human face undergoes a number of changes in expression that help to clarify what we are feeling and the emotions that we are undergoing during that interaction. If a person's face is passive and unresponsive, this violates the rules of normal communication, and the individual observing that passive face may interpret it as a personal rejection and respond with a surge of negative emotion.
The Still-Face Phenomenon
The impact that an unresponsive face has on communication has been clearly demonstrated in young human children using a procedure that is called the "Still-Face Paradigm." Typically, the test sequence is divided into three phases. In the first phase, which is usually called the "interaction phase," a person (the mother or an experimenter) actively interacts with the child. Then, in a second phase, which is usually called the "still-face phase," the person suddenly stops all interaction and becomes unresponsive. During this phase, the adult continues to look at the child but remains still and nonexpressive. Finally, to see if there are any after-effects, the interaction moves into the third phase, which is usually called the "reunion phase," where active interaction is restarted at the level that it was before.
Data from studies using this procedure show that the children really don't like the still-face phase. They break off eye contact, they stop smiling, and they show an array of more negative emotional signs when their reaction is compared to the previous phase of normal face-to-face communication. Physiological changes are also observable including an increase in heart rate and more stress-related hormones secreted into the child's blood. All of this is happening because the usual stream of active facial responses is no longer occurring between child and adult. Camila Cavalli, the lead researcher in this new study, wondered if dogs might also need to see an expressive face to comfortably communicate with humans. This seems like a reasonable presumption since there is evidence that the mind of a dog is roughly equivalent to the mind of a human 2- to 3-year-old.
Testing Dogs' Responses to Passive Faces
Actually, there were two studies in this report, where the major difference between the studies was in the dogs that were tested. In the first study, 62 adult dogs were tested, all of whom had been living with their owners for at least one year, while in the second study, 29 companion dogs who lived with their families were compared to 29 dogs who served as therapy dogs and had worked for at least one year with children, adults, and the elderly, in recreational visits, private psychotherapy, psychiatric units, and educational programs.
There was a very clever twist to this research, which came about because the data collection started during the peak of the COVID-19 pandemic. The data were gathered in individual Zoom sessions. This meant the dogs were tested in their familiar home surroundings. In most instances, two video devices were used (e.g., notebooks, cellphones, tablets), which allowed recording of a greater area of the room and more precise scoring of the dog's behavior.
The basic setup of the testing consisted of three 1-minute phases. The dog's owner sat on the floor and testing began with one minute of normal dog–human interaction. This was followed by the still-face phase where the dog's owner sat quietly, gazing at the dog while maintaining a neutral, unresponsive expression and not talking to the dog or petting it. Finally, in the third phase, normal human–dog interactions were resumed.
Unresponsive Faces Appear to Be Unfriendly to Dogs
Being confronted with a passive, unresponsive human face had an immediate and significant effect on the behavior of the dogs in much the way it did with human children. A lot of complex statistical analyses were conducted to tease apart nuances of the results, but it is possible to distill these down to some simple summaries. Averaging across the two studies, the data showed that the dogs demonstrated a clearly negative response to the still face. During the still-face portion of the study, dogs backed away from their owner with a 25-percent reduction in their closeness. There was a two-thirds reduction in the amount of time that they spent in physical contact with their owner. Perhaps most importantly, there was nearly a doubling of the signs of stress in the dogs when the owner was showing a passive face. That this was due to the dogs feeling that social contact had been removed was clear from the fact that there was a nearly 100-percent increase in begging behavior (where the dog offers a paw, scratches the owner, nudges the owner with his head, or barks) in an attempt to trigger some kind of positive response.
The amount of training that a dog had or whether it was a therapy dog or a companion animal made no difference in the results, suggesting that this is a fairly universal response of dogs, rather than something that comes about through its experience with people.
Thinking back at my own history of interacting with dogs, it has always seemed to me that my most successful communications with dogs have been when I acted much like a ham actor, making my expressions clear in the same way that I do when trying to talk to a child or an infant. That certainly seems to draw the dog closer to me and keeps him focused on what I'm trying to say in a positive way. The usefulness of employing such expressive behaviors seems to be confirmed by this newest set of data.
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Cavalli, C., Dzik, M.V., Barrera, G. & Bentosela, M. (2023). Still-face effect in domestic dogs: comparing untrained with trained and animal assisted interventions dogs. Learning & Behavior. https://doi.org/10.3758/s13420-023-00589-x