You may have noticed that when your dog hears a strange sound or when you ask him if he'd like to go for a walk, he cocks his head to the side.

The adorable move seems to say, "I'm listening," but what's really going on when dogs' heads tilt in response to a sound?

Here are a few possible explanations.

They're Trying to Hear Better

Dogs have movable earflaps that help them locate the source of a sound, but they also have brains that can compute time differences between the sound reaching each ear. A slight change in a dog's head position supplies additional information that the canine can use to judge a sound's distance.

Essentially, tilting the head can help the animal more accurately locate the location and distance of a sound.

They're Trying to Understand Us

According to Steven R. Lindsay's "Handbook of Applied Dog Behavior and Training," when a dog listens to your voice, he's trying to identify familiar words or tones that he associates with a reward, such as going on a walk or receiving a treat.

The muscles of a dog's middle ear are controlled by a part of the brain that's also responsible for facial expressions and head movements, so when a canine tilts his head, he's trying to perceive what you're saying, as well as communicate to you that he's listening.

They Can't See Our Faces Easily

In an effort to understand us, dogs not only use our words and inflection, but also facial expressions, body language and eye movements. Because of this, it's important for them to see our faces, so Dr. Stanley Corren reasons that when dogs cock their heads they're trying to see us better.

He says that dogs with longer muzzles have difficulty viewing a person's entire face and compares it to how our vision is obstructed if we hold a fist to our nose and view the world as a dog does.

Corren suggests that dogs may tilt their heads to view a speaker's mouth and aid in understanding what is being communicated.

He hypothesized that dogs with flatter faces, such as pugs, Boston terriers and Pekingese, might tilt their heads less because they don't have to compensate for prominent muzzles.

Corren conducted an Internet survey to test his theory. Out of 582 participants, 186 had dogs with flatter heads. Seventy-one percent of the people with large-muzzle dogs reported that their dogs often tilted their heads when spoken to, while 52 percent with flat-faced dogs reported frequent head cocking.

We've Taught Them to Do It

When dogs tilt their heads when we speak, it's undeniably cute — just check out the video below — and we have a tendency to respond to the behavior with positive reinforcement. Perhaps we say "aww" in a pleasing tone of voice or offer the dog a treat.

Reacting in such a way encourages the activity, and the more a dog is praised for cocking its head, the more likely he is to repeat the gesture in the future.