The research is done in a way that chows and most other truly independent breeds fail. They test things like repetious commands in a row, like sit ten times in a row, they also will put a towel or something over the dog's head and see if hey uncover themselves. Chows don't repeat commands over and over without a reason, and by the 5th or 6th time they are commanded to sit, they'll be looking at you like, "are you nuts? You told me to do that already, I did it, so now what." They also will not normally shake off a towel or blanket put over them because they didn't do it, so why should they remove it. If you scare them with it, they won't even allow it. They are perfectly capable of removing it, they just figure, you did it, you should remove it. Most of them don't fetch, especially after puppyhood, so that counts against them too.

Many chows aren't motivated by treats or toys, so it makes them hard to train with those rewards, and that to a lot of trainers makes them difficult to train and therefore they call them stupid. It's all about motivation, and the truth is chows aren't motivated by the things most dogs are motivated by. In my book that makes them very smart indeed, most of us say they are too smart for their own good.