It’s one of the dog’s cutest behaviors....When a dog appears to be listening or concentrating intently, it will sometimes cock its head to one side, seeming to imitate a human “confused” behavior. Humans don’t reliably do this, nor do cats -- so what’s going on?
There are a few different possible explanations. The most common explanation is that adjusting the position of the head can actually help the dog hear better, and thus analyze the situation better. A dog can hear things we can’t, but our blunt senses are much easier to use. We largely don’t have to adjust our physical positioning in order to hear, regardless of whether the sound is coming from our left or right. Dogs, though, whether because they get so much more information than we do or because their ears are more finicky, often have to adjust and many dogs with floppier ears--think basset hound--have a pesky (but cute) flap of skin in the way of their middle ear.
The part of the dog’s brain that controls the dog’s middle ear (not the external flap that we think of as the ear) is also the part of the dog’s brain that controls nonverbal communication. Those nonverbal communication tools include facial expressions and, yes, head tilt. So perhaps the act of listening also triggers some unintentional side effects.
One of the more interesting explanations is that the head cock doesn’t have anything to do with hearing. “It all has to do with vision. Try taking your balled fist and putting it right at the end of your nose. That does a decent job of simulating the effect of a dog’s extended muzzle--and it severely cuts down your field of vision. It has been found that dogs with longer muzzles cock their heads much more often than flat-faced dogs like pugs. And a dog would be more likely to perform this move when interacting with a person because it’s important for the dog to be able to see both our eyes and our mouths. Dogs want to see our eyes, because our eyes indicate what we’re interested in at the moment, and our mouths, because they indicate our overall emotional state. And it can be tough to see the entire face with a big nose in the way.
A more recent explanation is that the head tilt doesn’t so much help the dog concentrate on sight or sound as convey to whomever’s watching that the dog is concentrating. The tilt, according to this theory, is less a physiological tool and more the dog equivalent of our own nod: it means “I hear you, keep going.” That’s why less social dogs don’t display this behavior as often. Writes Steven Lindsay in his book “Handbook of Applied Dog Behavior and Training, Procedures and Protocols,” “Socially apprehensive and reactive dogs do not appear to exhibit the head-tilt response to human vocalization.” If the head tilt is a social act of communication, then why would a non-social dog perform it?
A study from the University of California at San Diego, playing off the social-animal theory, further suggests that the head tilt is an “indication to play,” making the head-tilt a sign not just that the dog is listening, but also engaged--and perhaps that it’s engaged because it wants something.
A final, less-studied explanation: Owners love the head tilt, and shower attention on their pup when it performs it (whether its through treats or head rubs or just laughter and attention). The dog, in turn, therefore will be much more likely to make that movement again. Which is fine with us, because it is adorable.