Why Do We Find Dogs' Eyes Irresistible?

Written and verified by the psychologist Sara González Juárez

Written by Sara González Juárez

Last update: 15 June, 2023

You’ve just settled down to eat, and then your dog approaches you, as they do every day, and waits for a morsel from your plate (even if you’ve never given them any!) You say “no”, and suddenly it happens…their eyes get bigger and their eyebrows droop. Are dogs’ eyes really irresistible, or is it our imagination?

Well, it seems that the softening of our hearts is more like a foreseeable fact than an illusion. A new study has delved into the facial expressions of domestic canids, with surprising results in this regard. Don’t miss it.

The domestication process of dogs

The origin of canids dates back to 50 million years ago; the first fossils considered to be canid fossils are from the Prohesperocyon period. Then, 30 million years ago, the first wolf-like and jackal-like canids appeared, related to our current-day dogs.

Around 15 million years ago, human populations in Eurasia were in the process of expanding, so it was inevitable that they would end up sharing habitat with the dogs in the area. It’s speculated that the dogs were attracted by the leftover food of the populations and crops, as it was easy food for them.

Over time, this cohabitation gave way to the domestication of the canids. Artificial selection by humans began, and this was the key to creating a much more gregarious and compliant character in domestic dogs.

Over time, this character would give rise to their use as pets, documented as early as Roman times.

“Look, they look like a person!”

How many variations of this phrase have you heard? When they bark back, when they snore, when they snuggle up on the couch and, above all, when they communicate with you. Dogs, except for certain unavoidable differences, have a unique ability to communicate with humans.

And this, although it may seem like chance, this isn’t the case by any stretch of the imagination. Dogs actually look at you, raise their eyebrows, and bend their ears to arouse your empathy. It’s a conscious and, by all accounts, useful act.

But how is this possible? The answer is simple and predictable: it is the work of humans, responsible for the domestication process you read about earlier. More on this later.

Why do we find dogs’ eyes irresistible?

Domestication transformed wild canids into dogs, affecting both their behavior and their anatomy. In just 33,000 years, this process transformed the anatomy of the facial muscles of domestic canines in such a way that it facilitated communication with humans.

A study published in 2019 explains this process. Our species artificially selected animals with the expressions closest to our own. In this way, generation by generation, they molded what is known today as “puppy dog eyes,” a facial configuration in which they enlarge their eyes and raise the inside of their eyebrows.

This expression increases pedomorphism or, in other words, similarity to a human baby or puppy dog. As you can imagine, big, glassy eyes and sad eyebrows produce empathetic and caring behavior in others, especially in the person who is observing them.

Indeed, your dog’s emotional blackmail works on a biological level.

Anatomical configuration of puppy dog eyes

As you’ve just seen, there’s no denying how irresistible dog eyes are. But how are dogs able to make sad faces?

The study investigated this process by comparing the facial anatomy and behavior of wolves and dogs. The results were revealing. While the former have a sparse and irregular set of fibers to raise their eyebrows, in domestic dogs it’s a developed and fully functional muscle.

Although we already know that wolves and dogs descend from a common ancestor (and not from each other, as was believed for a long time), the truth is that they are useful as a comparative pair if what we want to find out more about the effect of domestication. In fact, the only breed that has an underdeveloped brow lift muscle is the Siberian Husky.

We’ve made dogs as they are today

So, when it comes down to it, this whole process is due to humans! We have turned wild dogs into dependent, compliant, and docile animals. That’s why it isn’t surprising that their expressions resemble ours; we have simply ensured that the only genetic lines that survived were the ones that suited us the most.

Even so, this adaptation has worked in both directions; communication is more fluid and it’s difficult to resist their little faces, especially if the sclera (the white part of the eyeball) is visible in their expression. Yes, dogs’ eyes are irresistible, and science backs it up!