Baxter knows a lot of things that Kirby hasn't figured out yet and a lot of them have to do with knowing when to panic and when not to panic. When Bax was a puppy he would be startled by a loud noise...such as thunder...but only the first time he encountered it. He'd jump, look at us to see if it was something he should worry about, and if we didn't react negatively, he'd let it go. I think this is the wiring of a gun dog.
Kirby, on the other hand, is a bit more tightly wound, so when there's a loud noise, he has only two reactions: if it's close, run and hide and if it's farther away, bark at it (and sometimes run and hide).
One area where Baxter has clearly adapted to the noises of daily life is kitchen accidents. Baxter has learned that a loud noise followed by "oops!" or "(expletive deleted)!," means that there may very well be something tasty on the floor and within his reach.
The other night I was fixing dinner and I accidentally knocked a bottle off the counter. Fortunately it didn't shatter, but it did make a very loud noise that sent Kirby racing under the couch with his tail between his legs. True to form, Baxter passed Kirby going the other direction and within seconds was in the kitchen surveying the floor. Nothing good this time. He looked disappointed.
Kirby waited under the couch until his dinner was served.