Your trials are not unique, as some Yorkies like to behave as little children, testing their humans to find the boundaries. I know it's not "psychological" behavior, as dogs do not think (at least, not in the human sense), but they DO exhibit many traits of children who require discipline and consistency. Just keep up with the rewarding of good behavior, and the "discipline" of bad behavior. Now, with our little Graysee, she seemed afraid of a rolled-up magazine or newspaper; we had only to wave it at her, or smack our leg lightly with it, and it gave her such a start that she would immediately stop her acting up! I have read that this is not good practice, as it instills fear, but it worked with her, and now that she's five, I never have to even say the word "newspaper" to get her attention. I simply snap my fingers, and she pays attention. She did like to sneak into our closet and steal socks, underwear, slippers, etc. when she was little, but that didn't last too long. And, if she growled and/or bit, we would immediately turn our backs on her and ignore her, sometimes even leaving the room. That hurts, as she wants to be with her humans as much as possible, and any hint of rejection causes a reaction. That is what we are looking for; a reaction to OUR negative reaction to her unacceptable behavior. Today, Graysee only growls a "fake" growl when we're really playing hard, and I try to take away a toy. If I insert my finger into her mouth when she growls, she will stop the growling and open wide so as not to accidentally bite me! In fact, she has only actually bitten ONCE, and that was when one of the grandchildren picked her up roughly and hurt her. Of course, both dog and grandchild got scolded for that incident. I wouldn't worry at this stage that you're raising a monster; give it some time, and remember to be consistent with both the rewards and the discipline. She will learn, as Yorkies are pretty smart little dogs!
