The next time you want to know how your dog feels about you, don’t focus only on the wagging tail. If he’s happy to see you, it’s written all over his face.
Scientists in Japan decided to investigate how dogs’ facial expressions might reveal their reactions to a variety of emotional stimuli when placed in an unfamiliar situation. The results of their study were published in July in the journal Behavioural Processes.
In the experiment, researchers positioned 12 dogs, one at a time, on one side of a partition. Each dog was able to observe through an opening what was happening on the other side. Scientists then presented each dog with certain stimuli — a stranger, a doggie toy, an item they disliked (such as nail clippers) or the dog’s owner — that the dog could see when a black curtain on the other side of the partition was opened.
The research team recorded each dog’s reactions by tracking facial movements. They marked the dogs’ ears, eyebrows and the points on the head directly between these markers. They then used a high-speed video camera to record the dogs’ reactions when they saw the emotional stimuli.
As it turned out, when dogs saw their owners, they tended to lift their eyebrows, especially the left one, within a second or less of getting a first glimpse. They often lifted their eyebrows when they saw any person on the other side of the partition, but the left eyebrow lifted markedly more often when dogs saw their familiar human companion.
Other results of this study were just as interesting. When the dogs saw a person they’d never met before, they shifted their left ear back just a bit. No particular eyebrow or ear movement was associated with seeing a doggie toy. However, when the dogs saw something they did not like (oh, those detestable nail clippers), often the right ear moved back a little.
“It is difficult to explain this difference in movement between the ears and eyebrows,” Dr. Miho Nagasawa, of Azabu University’s Department of Animal Science, told The Telegraph.
“Dogs’ ears are prominent features used to convey emotional expression, therefore our results suggest that dogs were more cautious toward unfamiliar people,” he said. “In contrast, eyebrow movement might indicate a visible response whereby dogs attempted to look at their owners more intently.”
This study seems to complement another released earlier this year, in which researchers determined that humans are pretty adept at reading dogs’ emotions simply by looking at pictures of their faces. In this study, 50 volunteers with varying degrees of dog experience looked at a set of photographs of one dog named Mal.
The photos showed Mal’s expressions as he was praised, surprised, reprimanded, angered, disgusted by medicine he didn’t like and made fearful by seeing a pair of those universally hated nail clippers.
The volunteers were most successful at identifying happiness in the photo taken when Mal was praised. They were least able to discern surprise and disgust.
The study leader, Dr. Tina Bloom, and her team believe that reading dogs’ faces came easily even to the volunteers with little experience with dogs because of a naturally evolving empathy. We may have an innate human ability to understand dog emotions, which has developed over the course of centuries. It could help explain why humans and dogs have been such devoted friends through the ages.
These two studies show that we humans can read our dogs’ emotions pretty accurately much of the time. Now, when we want to know for sure if our dogs like us, remember that a little lift of an eyebrow tells the real story.
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