How dogs give you that look
You know that face your dog makes, the one that’s a little bit quizzical, maybe a bit sad, a bit anticipatory, with the eyebrows slanted? Sometimes you think it says, “Don’t be sad. I can help.” Other times it quite clearly asks, “No salami for me?”
Scientists have not yet been able to translate the look, but they have given it a very serious label: “AU101: inner eyebrow raise.” And a team of evolutionary psychologists and anatomists reported in Proceedings of the National Academy of Sciences that dogs make this face more often and way more intensely than wolves. In fact dogs, but not wolves, have a specific muscle that helps raise those brows.
An example of the look can be found in a talking-dog video that nearly 200 million people have watched online. The dog can twitch its inner eyebrow because it has a muscle called the levator anguli oculi medialis. It can talk because it’s a YouTube video. That part has nothing to do with science.
“I think the study is compelling,” said Clive Wynne, a psychologist at Arizona State University and head of the Canine Science Collaboratory.
It is, Wynne said, “another piece of the puzzle of what connects dogs to people.”
Wynne, who was not associated with the study, said that a greater number and variety of the two species would need to be studied to learn more about the differences between dogs and wolves.
How humans and other animals communicate by looking at each other is a matter of great interest to scientists. Anne Burrows, an anatomist at Duquesne University in Pittsburgh, studied chimpanzee faces. She and other researchers, including Juliane Kaminski, an evolutionary psychologist at the University of Portsmouth in England, joined together a few years ago to look at domestic animal facial expressions and musculature.
They started with horses and cats. Horses have facial movements similar to dogs, but cats do not.
The team tested dog and wolf behavior by videotaping their reactions, and, as expected, dogs did raise their eyebrows more often and more intensely than wolves. Even though wolves don’t have that muscle, they have a lot of other muscles so they can do a bit of the look.
Researchers dissected the heads of four wolves and six dogs. As might be expected from animals so closely related, all the musculature was alike except for the levator muscle, which none of the wolves had. One other muscle, which varied in the wolves and dogs, was also related to eye movement.
The scientists hypothesize that humans have unconsciously favored eyebrow-raising dogs during fairly recent selective breeding.