According to newly-published research, dogs have perfected the eye brow raise by using facial muscles that are stronger than their cousins, the wolves. Over thousands of years of dog domestication, people preferred pups that could pull off that sad sack, take-care-of-me look. And that, in turn, encouraged the development of the facial muscle that creates it.
“The researchers believe dogs, over their relatively short 33,000 years of domestication, used this eye muscle to communicate, possibly goading people to feed or care for them — or at least take them out to play. And people, perhaps unwittingly, obliged.” [source]
A paper entitled “Evolution of facial muscle anatomy in dogs” has been published in the Proceedings of the National Academy of Sciences. It concluded that canine aces are structured for complex expression in a way that wolves are not. This is due to a special pair of muscles framing their eyes. These muscles are responsible for that “adopt me” look that dogs can pull by raising their inner eyebrows. “It’s the first biological evidence scientists have found that domesticated dogs might have evolved a specialized ability used expressly to communicate better with humans.”
Example of facial movement AU101 (inner brow raiser) in a domestic dog (Rhodesian Ridgeback, not a subject in the study), increasing the height and overall size of the orbital cavity (eye): A) neutral on right side of face, B) AU101 on right side of face. [source]
DOG MUSCLES: RAOL and LAOM
For the study, a team at the University of Portsmouth’s Dog Cognition Centre looked at two muscles that work together to widen and open a dog’s eyes, causing them to appear bigger, droopier, and objectively cuter. The retractor anguli oculi lateralis muscle and the levator anguli oculi medialis muscle (mercifully known as RAOL and LAOM) form two short, straight lines, which connect the ring of muscle around a dog’s eye to either end of the brow above. [source]
“We connect profoundly with animals capable of exaggerating the size and width of their eyes, which makes them look like our own human babies and “hijacks” our nurturing instincts. Research has already demonstrated that humans prefer pets with more infantlike facial features, and two years ago, the authors of this latest study showed that dogs who made the facial movement enabled by the RAOL and LAOM muscles—an expression we read as distinctly humanlike—were more likely to be selected for adoption from a shelter than those who didn’t.” [source]
“Research has already demonstrated that humans prefer pets with more infantlike facial features.”
SHELTER & RESCUE DOGS
I know from my personal experiences with shelter and rescue dogs, that a sad puppy look can just melt your heart. Dogs certainly have the ability to tell you how they feel with just a look. A good loving stare will help a needy dog find a home. Maybe that is why we love our dogs so much. Dogs have endeared themselves to humans with their soulful eyes. It makes us want to care for them and give them a good home. Adopters will often mention they were taken in by a dog’s longing look. The best puppy eyes get the most attention. That is how I fell in love with my rescue dogs, Terra and Frazier.
Chihuahua’s large dark eyes are especially expressive. My dogs can be as naughty as ever but manage to say “I’m sorry” with a glance, even though they really aren’t! Chihuahuas always have puppy eyes even when they are old and grey. I think that is why they are my favorite breed. I love their sweet faces and beautiful eyes. My Rocky has the biggest deep brown eyes and the best stare of my pack of Chihuahuas and he knows it. My Carl who passed away last winter also had the most expressive eyes. I miss him everyday.
When I look into all of their eyes, I just smile and immediately want to pet them — smart pups!
REFERENCES:
Scientists take a peek behind those sad puppy dog eyes [dailystandard]
NCSU, Duke researchers help unravel the mystery of puppy dog eyes [wraltechwire]
Dogs may have developed ‘puppy dog eyes’ to communicate with us [wcnc]
Scientists take a peek behind those sad puppy dog eyes [newsday]
Do you have a weakness for puppy dog eyes? [post-gazette]
Example of facial movement AU101 [researchgate]
Paedomorphic Facial Expressions Give Dogs a Selective Advantage [researchgate]
Dogs’ Eyes Have Changed Since Humans Befriended Them [theatlantic]
Evolution of facial muscle anatomy in dogs [pnas.org]
The Anatomy of Seduction: Raised Brow Puppy Dog Eyes [psychologytoday]
M Waller, Bridget & Peirce, Kate & Correia-Caeiro, Cátia & Oña, Linda & Burrows, Anne & Mccune, Sandra & Kaminski, Juliane. (2013). Paedomorphic Facial Expressions Give Dogs a Selective Advantage. PloS one. 8. e82686. 10.1371/journal.pone.0082686.