Ask the AKC Animal Behaviorist - Why Does My Dog Bark at Doorbells on TV?
Q: Why does Gus, my 2-year-old German shepherd, bark when the doorbell rings on a television show? We've never even had a doorbell, so it's not like he's expecting someone. Is it just the sound that bugs him?
A: When most dogs bark up a storm upon hearing the doorbell, it's because they're pairing the sound with what happens next. Doorbell rings; stranger appears at door. In behavioral terms, we would say the sound of the doorbell has generalized if the dog also barks when he hears a doorbell on television.
But, in your case, you've told us that you don't have a doorbell and Gus barks when he hears one on television. Has Gus ever been exposed to a doorbell, so that he learned that the sound is a signal strangers might appear?