A couple of days ago I was talking about the difference between guilt and shame, and I have a favorite metaphor for this. Dogs can learn to feel guilty. Cats can't learn guilt, so they can only be taught shame.
You get home. While you were away, the dog knocked a vase off of a piece of furniture. It broke, and there are dead flowers in the middle of a smelly puddle in the next room. But before you even get there and see it, you know that something happened. Why? Because the dog is sitting at the door, and its posture just reeks of humiliation and shame. The dog knows that it did something bad, and it is terribly, terribly ashamed. Whatever punishment you might mete out doesn't even figure into it. The dog is already punishing himself, because he knows that he let you down. The dog let himself down, failed to live up to the standards you taught him.
You get home. While you were away, the cat knocked a vase off of a piece of furniture. It broke, and there are dead flowers in the middle of a smelly puddle in the next room. Depending on how friendly and emotionally needy your cat is, and/or how busy it is, the cat either meets you at the door or not. But if it does, there's nothing in the cat's demeanor to suggest that anything is amiss. When you get into the next room and find the mess, for all I know the cat jumps down and starts batting at the dead flowers or kneading smelly water out of the carpet, just for something to do. Then, when the cat notices that you're looking, and your body language says "angry," the cat visibly goes, "Oh, shit, here comes violence." But the body language still doesn't bespeak shame or guilt, just anger and/or fear. The cat makes a break for it. And whatever punishment you give the cat, the cat hisses at you, is terribly offended, and won't speak to you for 15 minutes, that is to say, until it no longer remembers why it's mad at you.
The dog acknowledges that you, as pack alpha, get to set the rules, the moral agenda for the pack. It has internalized your values, to the best of its ability to understand them. And no matter how foreign those rules are to its doggy nature, it knows that when it breaks one of your human rules, it has committed some awful violation of the laws of nature and the laws of the pack that no Good Dog would do. Only a Bad Dog would do that. So it feels horrible, it feels like a Very Bad Dog to have done such a thing.
The cat, on the other hand, has its own moral code. There are probably things that you think poorly of that the cat doesn't give a crap about. There are probably things that you do that deeply morally offend the cat. But no matter how dominant you are in the cat's life, no matter how much the cat loves you, the cat is never going to change its moral code to suit yours. You can teach a cat to be careful to hide what it's doing sometimes. You can teach the cat to feel fear about breaking your rules when you're looking, or close enough to catch it in the act. You can teach the cat that certain acts have a high percentage chance of resulting in punishment, and not to be willing to gamble on getting away with it. But you can't make the cat feel guilty.
Once the dog learns that only a Bad Dog, a dog much worse than any dog it has ever met, would break the Master's rules, you don't have to watch the dog night and day. But trying to get a cat to obey a rule that isn't natural to cats is a constant struggle of wills between you and the cat, and the cat will promptly forget and/or ignore the rule whenever it's not being watched.
And that is why so many of society's methods of social control of behavior depend on cognitive dissonance at best, and deliberate willful ignorance by choice. Mundane society would much rather that you not know that children are a hundred or so times more likely to be molested by a close family member than by a stranger. Society would rather that you not know that on average, one third of all merchandise that enters a retail store by way of the loading dock leaves other than by the register, and that 3/4 of that is stolen by employees. Society would rather you didn't know that the clearance rate, the ratio of solved crimes to reported crimes, runs around 40%. Society would rather you didn't know that your parents, children, or spouse are the people statistically most likely to murder you. But if you do find these things out, and you're a dog rather than a cat (that is to say, if you internalize society's rules rather than obey them for your own reasons or out of fear), they depend on you promptly forgetting what you know and never thinking about it.
Sexual abuse of children may only be spoken of when we're talking about non-humans like Michael Jackson, or people in unusual professions with distinctive dress like Catholic priests, and never in terms of mom's boyfriend. Murder may only be spoken of in terms of random street crimes, never in terms of husband on wife except under the most heart-rending of circumstances. Theft and embezzlement must be spoken of as massive violations of the public trust, something that only a total monster would do, and not as something that almost all employees, including white collar ones and executives, engage in to some extent. And as much as possible, after a certain amount of time no unsolved crime should ever be mentioned again, and especially not ones where the criminal escaped across a border. As much as possible, crime should be spoken of only jokingly in the form of endless lists of "stupid criminal" stories where the criminal got caught because all criminals are so stupid that the reader or listener can't possibly identify with the criminal, that they instinctively feel superior to the criminal. People must believe that crime is only committed by the unusually morally depraved, the retarded, and/or easily identifiable "others" that the rest of the people can feel superior to.
Why? Because society depends on people thinking that nobody like them, nobody they identify with as an equal or an aspiration, would ever even want to commit a deviant act. As long as they believe that, their fear of letting themselves down, of revealing themselves to be an unusually awful and inferior deviant, will keep them in line. They don't have to fear getting caught. It's enough for them to fear knowing what kind of an awful person they are.
To give another example, that's why Kinsey's original book Sexual Behavior of the Human Male was such a shock that society has never fully recovered from it. As I mentioned on at least one other occasion, when it comes to any one of society's rules the population can be divided into three categories: those who would naturally live by the rule, those who can't possibly live by the rule or who won't be allowed to do so, and a third middle group who could go either way. Much of the mechanics of social control is aimed at keeping that third group on the straight and narrow. Now let's play a little bit with the various surveys aimed at determining what percentage of society "is" homosexual. The way I read the shifting responses to subtle changes in the question is that something around 0.5% of society is going to swing that way no matter what, that somewhere between 4% and 10% of society would be gay or bi if they had little or no reason to fear doing so but can be persuaded not to, and the remaining 85% to 90% are straight as string. In this particular example, one of the mechanisms for minimizing the amount of homosexual behavior in pre-Kinsey society was to make every single "friend of Dorothy" feel so awful about it, to think that they must be a monster to even feel attraction for a person of their own gender, that they would never even mention it, let alone act on it. And after all, if they feel so guilty that they can't even tell the other person, then neither of them will ever know, and there's one less GLBT couple to undermine societal values.