Why Do Floppy-Eared Dogs Seem Friendlier?

You see a German shepherd and a golden retriever at a park. Which one do you want to pet?

A lot of people might perceive the German shepherd — with its pointy, upright ears — as a little more off-putting and maybe even scary. But the floppy-eared retriever seems friendly and sweet and just asking for a cuddle.

We all make judgments about dogs (and people, for that matter) based on certain characteristics. In dogs, one of those things is the shape of their ears.

Recently, the Transportation Security Administration (TSA) has been using more floppy-eared dogs to sniff out explosives because the agency says pointy-ear dogs are scarier.

"We've made a conscious effort in TSA ... to use floppy ear dogs," TSA Administrator David Pekoske told the Washington Examiner. "We find the passenger acceptance of floppy ear dogs is just better. It presents just a little bit less of a concern. Doesn't scare children."

Around 80 percent of the 1,200 canines the agency uses in the U.S. have droopy ears, according to the TSA. The agency uses seven types of dogs: five with droopy ears (Labrador retrievers, German short-haired pointers, wire-haired pointers, vizslas and golden retrievers) and two with pointy ears (German shepherds and Belgian Malinois).

But even though the dogs are friendly looking, they still have a job to do. Floppy-eared or not, they aren't to be approached when they're on duty, says the TSA.

A look at science

Charles Darwin thought a lot about ears when considering evolution, as the NPR video above explains in more detail.

"Our domesticated quadrupeds are all descended, as far as is known, from species having erect ears," Darwin pointed out in "The Variation of Animals and Plants under Domestication." "Cats in China, horses in parts of Russia, sheep in Italy and elsewhere, the guinea-pig in Germany, goats and cattle in India, rabbits, pigs and dogs in all long-civilized countries."

In many species, ears seemed to flop when they no longer needed to be erect to catch every passing sound, Darwin mused. He called the phenomenon domestication syndrome.

More recently, in a 2013 study, Suzanne Baker of James Madison University in Virginia and Jamie Fratkin of University of Texas at Austin showed 124 participants images of a dog. In one, it was the identical dog, but it had a yellow coat in one photo and a black coat in another. The other photos showed the same dog but in one image it had floppy ears and in the other it had pointed ears.

Participants found the dogs with a yellow coat or floppy ears to be more agreeable and emotionally stable than the dogs with a black coat or prick ears.

But why the bias?

Although there are plenty of people who love pointy-ear pups, why are so many wary of them? There are no studies that show prick-eared dogs are less friendly than their floppy-eared counterparts, says Elinor K. Karlsson, assistant professor at the University of Massachusetts Medical School and the Broad Institute of Harvard and MIT and founder of Darwin's Ark, a citizen's science project centering around genetics and pets.

Instead, it's likely that people base their opinions on past experiences they've had with dogs.

"If people do perceive floppy eared dogs as being 'friendlier looking,' it could be just because dogs they've known personally are more likely to be floppy eared," Karlsson tells MNN, pointing out that Labrador retrievers, the most common breed in the U.S., have floppy ears.

In addition, many of the working police and military dogs people meet are breeds such as German shepherds and Belgian Malinois, which tend to have erect ears. So people may associate the ears with the working dogs which are in protector, not friendly, roles.

Karlsson says this kind of "perception bias" can affect how people see and interact with dogs, which is why she's very interested it this theme in her research.

"People do have a habit of assigning characteristics to things based on general groupings," she says. "People do this to humans as well. It's the way ours brains work."