When your dog cocks his head from side to side, it's not because he knows you think it's cute -- not always, anyway. He does it for a combination of reasons, but they aren't all adorable. It could indicate an illness, so watch out for other signs of health trouble.
A dog who tilts his head often could be suffering from poor balance, and is trying to compensate. Your dog's vestibular system, deep down in his inner ear, controls his balance and his ability to gauge his posture. Vestibular disease, which can be caused by conditions such as injury, nutritional deficiency, parasites or more, affects the vestibular system. Your dog's balance suffers, and he tilts his head to try to stay level. Other symptoms include frequent falling down, nausea and poor coordination -- if your dog appears to be struggling, contact your vet.
Your dog may tilt his head when you speak to him as a way of trying to hear you more clearly -- think of it like adjusting your earbuds when you listen to music. While dogs generally have excellent hearing, their outer ears don't automatically adjust and hone in on sounds like yours do. He has to tilt and turn his head as a way of funneling sound into his ear. You may notice that he does the head tilt more often when you're directly in front of him than when you're to the side -- that's because when you're face-to-face, the sound isn't going straight into his ears, and he has to point them at you.
Dogs don't communicate by listening alone -- they are visual communicators that rely on body language. In fact, they communicate with body language so much that the same part of the brain that controls listening to sound also controls movements of the head and face. This means that while your dog is listening to something, like you asking him for the hundredth time who a good boy is, he's working his face and head muscles to "talk" back, and show you his reaction and/or comprehension.
Dogs learn from consistency. When it comes to getting positive attention from their people, they can learn quickly. When your dog does something cute like tilting his fuzzy little head, you can't resist fawning a little bit -- it's OK to admit it. Once your dog gets that positive reaction from you a few times, though, he realizes that tilting his head is the key to making you gush -- and he'll milk it for all it's worth. Dogs aren't always too proud to perform a little, especially when affection and treats are at stake, so sometimes they just tilt their heads because they know how much you love it.
Tom Ryan is a freelance writer, editor and English tutor. He graduated from the University of Pittsburgh with a degree in English writing, and has also worked as an arts and entertainment reporter with "The Pitt News" and a public relations and advertising copywriter with the Carnegie Library of Pittsburgh.