SciShow host Michael Aranda offered several examples that may explain why dogs tilt their heads, particularly when a human is speaking. The first theory supposed that it makes it easier to see the lower half of the human’s face depending on the dog’s muzzle, while the second theory also noted that it made for easier hearing. While a third added body language into the mix.
A third take from a dog trainer named Steven Lindsay is that dogs tilt their heads because one part of their brain is involved in both listening and body language. We think a region called the nucleus ambiguus controls a dog’s head movements, as well as the muscles in a dog’s middle ear that help it perceive subtly different sounds. So Lindsay suggests that when your pup is listening, it can’t help but show you with its body too.