Dogs often copy the facial expressions of others, according to a new study that suggests dogs, like humans and other primates, show a phenomenon known as "emotional contagion."
Emotional contagion, which is a basic building block of empathy, is when an individual instantaneously shares the same emotional state of another. Its existence was never fully proven in dogs until now.
Dogs and humans that are closely bonded to each other start to mimic each other for a very useful reason.
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"If you live in a group and you share with companions many interests and goals, you must understand his or her emotional state, and the only way to do that is to 'read' his or her behavior and facial and body expressions," explained lead author Elisabetta Palagi.
Palagi, who is president of the Italian Primatological Association, added, "Via emotional contagion, you take part in a social life; you create an emotional bridge between you and others. It is essential for the social life to evolve."
Palagi is also a researcher at the University of Pisa's Natural History Museum as well as at the Institute of Cognitive Sciences and Technologies in Rome. For the study, published in the journal Royal Society Open Science, she and colleagues Velia Nicotra and Giada Cordoni analyzed the behavior of dozens of female and male dogs, representing multiple breeds and ages, at a dog park located in Palermo, Italy.
The researchers documented that in less than one second, many of the dogs would copy the expressions and behaviors of other dogs. For example, if one dog would position his body in a play bow, indicating readiness to play, another would do so near instantaneously. If a dog exhibited a relaxed, open-mouthed face - signifying friend not foe among canines - then the other dog would tend to do the same.
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Such mimicry was strongly affected by whether or not the individuals were already familiar and socially bonded with the other. In short, the closer the dog friendship was, the more the two dogs' moods and appearance would be in sync.
Given the closeness of dogs to humans, and with reams of anecdotal evidence, the authors believe that dogs can take on our expressions and feelings too, especially if they are closely bonded to their owners.
"It is an automatic response, similar to that of humans when they see someone crying or smiling," Palagi said, adding that domestication probably even enhanced dogs' natural inclination toward emotional contagion all the more.
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Prior to the new study it was known that human yawning could prompt certain dogs to yawn, but the extent of the mimicry and emotional contagiousness was not known until now. Dog experts contacted by Discovery News were astounded by the new findings.
Marc Bekoff, a professor emeritus of ecology and evolutionary biology at the University of Colorado and the author of "The Emotional Lives of Animals" said that he and his students have conducted decades of research on dog play, "but we hadn't invoked mimicry as one reason they could vigorously play and share intentions to play and maintain the play atmosphere. Now, Dr. Palagi and her colleagues have shown that the ability to maintain a 'play mood' most likely rests on rapid mimicry and emotional contagion."
Sergio Pellis, a professor and board of governors' research chair at the University of Lethbridge's Department of Neuroscience, said, "This is a well thought out paper that is superbly executed and consequently provides very compelling data."
He likened the copycat moods and expressions to playing peek-a-boo with an infant.
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"As the cloth is pulled down, the baby smiles, and unless you are a psychopath, you also involuntarily smile; moreover, you feel happy," he said. "While this relationship between action and emotion is well established for humans, rapid facial mimicry has only been recently shown for some other primates, including the work by Palagi and others."
With the new determinations about dogs, Pellis now suspects that other social mammals could reveal such behavior too, so perhaps "Grumpy Cat" really is grumpy, if its owners are often in a bad mood.