There are many reasons why your dog may tilt his head to one side. Medically, if it is consistently tilted to one side involuntarily, it can mean there is a medical problem. Health issues can range from an ear infection or a lodged foreign object, to a brain issue such as an infection, inflammation, cancer, or other mass. In these cases, your veterinarian should examine your pet and determine what treatment may be necessary.
However, when he hears a sudden noise such as the phone, doorbell, or your voice, his head may tilt to one side as if he is trying to figure out what the noise is or what your words mean. While he may be trying to make sense of what he hears, Dr. Meredith Stepita, a Diplomat of the American College of Veterinary Behaviorists, says that experts believe the dog thinks there is the possibility that what is being said could lead to something important – an activity he likes or a treat, for example. Dogs can understand some human language, and the head-cocking may indicate the dog’s concentration. He is looking for familiar key words or an inflection in your voice that often leads to that favorite activity, such as “Want to go for a walk?”
Experts also note that the manner in which a dog hears will also play a part. Dogs’ movable earflaps help them locate the source of a sound. Dogs’ brains can also compute extremely small time differences as the sound reaches each ear. The slightest change in the dog’s head position supplies information in determining the distance, location, and height of the sound.
All of these factors, in addition to the owner’s reinforcement of the behavior, make this behavior occur more frequently. While there is no study showing head-tilting is a sign of intelligence, it was noted that that dogs with socialization problems are much less likely to engage in the head tilt when people speak. So if your dog’s head doesn’t tilt, it could simply be his way of saying, “I’m not listening!”