As far as I can tell, cats forget easily, and for whatever reason she understood the "spanks". I think she equated it to dominance. She's a part feral animal after all. Responding to aggression with aggression must be a primal instinct for an animal. Dogs sense fear for example, and if an animal gets his or her way through aggression consistently there's no reason to stop I wouldn't think. To anybody who says, "your cat will be afraid of you", I can honestly say they were correct. She feared my hands for a while. It took consistent, delicate work to get her over that.

I drew some correlation at one point between her not wanting to be pet on the back and the severe discipline. It was severe. I won't try to deny it. But it worked. Now, after ending the spankings for long enough (wasn't long, only a month or a little more), she'll let anybody pet her anywhere and she remembers the no biting policy. At this point she hasn't bitten me in I don't even know how long and she's more tender and affectionate than ever before.

I don't know if I handled the biting in the most humane way but it was effective and she shows no signs of any lasting negative effects.