A study in which people judged dogs by photos of their faces reveals the emotional as well as the biological connection humans have with animals.
We love our pets, and we feel like we understand them.
But is that true?
How could it be, when we are two species separated by millions of years of evolution?
According to a Finnish
That makes sense, says the study’s lead author, Miiamaaria Kujala, Ph.D.
Empathetic people have already been shown to make quicker, better assessments of facial expressions in other people.
“In our study, we wondered if this ability extends to perception of dogs, since dogs and humans share much of the common mammalian facial musculature, and dogs are overall quite expressive,” Kujala told Healthline in an email.
To test this theory, Kujala and her colleagues showed 30 volunteers close-up photos of dogs and humans, along with pictures of objects and blurry images.
About a third of the faces were meant to look happy, a third neutral, and a third threatening.
After rating and describing the emotional state of the subject in each picture, volunteers were given a personality test and asked to describe their experience with dogs.
In general, the volunteers agreed that happy faces were happy, neutral faces were unemotional or a little sad, and threatening faces were angry and aggressive — no matter whether the face was human or dog, and no matter the person’s prior experience with dogs.
“So even without training, we may understand some of the dogs’ emotional gestures if [they are] similar enough to the human respective gestures,” Kujala said.
Read more: Pets can be healthy friends for people with rheumatoid arthritis »
That’s probably not a coincidence.
Humans and dogs go way back and we’ve influenced each other in major ways.
Some studies suggest that humans bred dogs to be less aggressive and more puppylike. In fact, a recent study found that dogs in shelters that made “puppy eyes” found homes faster than other dogs.
Dogs and humans are so tied to each other that we share some of the same genetic characteristics, as though we’ve evolved in tandem.
Researchers at the University of Chicago estimate that dogs were domesticated as long as 32,000 years ago, and in that time the two species have developed similar genetic markers for diet, neural processing, and disease.
Read more: Debate heats up over growing human tissue in farm animals »
With findings like that, perhaps it’s not surprising that scientists are increasingly trying to understand how we connect with other animals.
Kujala is part of a research group in Helsinki that explores the connection between animals and people using noninvasive methods like tracking eye movements and measuring brain activity with electrodes placed on the scalp.
This study relied, in part, on a new coding system known as Dog Facial Action Coding System, or DogFACS.
The original FACS was first developed as a way to deconstruct the expressions on human faces in the 1970s, and since then spinoffs have been created for chimpanzees, monkeys, horses, and even cats.
Sometimes things get lost in translation.
One expression that seems prone to misinterpretation is the smile — or at least, the tendency to pull back one’s lips and show one’s teeth.
In wolves and rhesus monkeys, that look is thought to be a
The current study showed that people do indeed have some biases when they look at dogs.
Volunteers rated pleasant human faces as happier than pleasant dog faces and threatening dog faces as more aggressive than threatening human faces. People also described the pleasant human faces as more intense than pleasant dog faces, as if gauging happiness is easier in people than in dogs.
Those results “may reflect the biological and ecological importance of our own species to us, and that the potential threat from other species is commonly estimated as higher,” Kujala said.
She added there’s no way to know for sure that the faces in the photos didn’t actually differ in intensity in some unmeasurable way.
Her lab’s previous work found that people who were more experienced with dogs were more adept at reading their body language.
But in this study, where only a dog’s face could be seen, experience didn’t matter as much. The ability to read a dog’s face seems to be more or less intuitive.
As expected, that proved to be especially true in volunteers who scored high in emotional empathy. They were particularly quick in their assessments and rated the dog expressions as more intense.
When it came to cognitive empathy, though — the ability to share someone else’s perspective — there was no such link.
In other words, we can’t quite put ourselves in a dog’s place, but we may be able to tell from its face how it feels.