Ok, clearly there is no answer to this one, as we can only speculate. But I'm curious for people's feedback, and here's what got me wondering:
Jack knows the names of all his toys. When we bring a new one home, we say the name clearly two or three times, throw it for him, and say "Get (name of new toy)!" and that's how he learns the names of something new. The way we trained him to realize that things have names was a bit more involved, but now that he knows the concept, naming new objects is easy.
When he looks bored, sometimes I'll send him searching for a toy I haven't seen in awhile. So, I might say "Jack, where's Ultra Ball?" with an emphasis on the questioning tone of voice. The hunt is on, and he'll check his toy basket, behind the door, under some shelves, in his crate, until he finds the object. He trots around with a very matter-of-fact look on his face, and I assume that he is looking the way I would look: that is, he has a mental image of "Ultra Ball" in his head and is muttering some doggy version of "Where IS Ultra Ball? Where did I leave it? Is it behind here? Under here? Back there?" the whole time.
But sometimes, in talking to my dog the way one will, I might ask "Where is..." when I am looking for something of my own, something that he does not know the name of. And off he toddles, looking just as intently as he does for his own toys, trying to find I'm-not-sure-what.
Just now, I was wondering where the cat was, and I said "Jack, where is Kitty Boo?" (the cat's name is Boo, but somehow we've changed it to Kitty Boo without even realizing it).
Off went Jack, that same look on his face, but clearly he wasn't looking for the cat because he walked right by her. He checked behind the door, behind the sink, under the hall table, in the dining room, by his crate. The longer he looks, the more intent he gets. To my human brain, I assume he's holding a picture in his head of an object, and looking for it.
But watching his behavior, I now wonder if the opposite is true: he knows that "Get xyz" means I want an object. But maybe until he SEES the object, he does not know what he's looking for? That is, if I say "Get tennis ball" perhaps he does not hold a picture of tennis ball in his head, but as he sees objects, he labels them and dismisses them as "not tennis ball" until he sees the one that triggers the "Tennis ball!" response in his brain. That is, he knows it when he sees it, but until he sees it he cannot picture it.
Not sure if I'm making sense, but the fact that he will look just as thoroughly for something that he has no concept of as for something he "knows" the name of puzzles me. And just to clarify, he has never actually come back with an object when I unintentionally send him on the hunt for something he does not know.
Anyone have any insights on those doggy brain cells to enlighten me?