So it’s not that your dog is either smart or stupid. It’s that she’s both smart AND stupid.
They’re incredibly vapid when it comes to understanding the physical world, things like understanding that if you’re connected to somebody with a leash you can’t go on the other side of the lamppost. There’s good evidence that that really is a cognitive constraint. They just don’t get it.
Here’s a Fresh Air interview that demonstrates the dogs-are-smart half of this subject. It’s about training dogs for search-and-rescue missions