Either you accept it, meet your duties, and hold others to theirs--or you are antisocial.

If you still don't think this is easier said than done, you haven't learned anything from this discussion. Confabulation under stress is a fact of human psychology. You can't make it go away by just saying "try really hard to keep your story straight".

You are missing an important fact about police: They are not your friends, especially not if they are investigating a case and (rightly or wrongfully) suspect you of being involved. Police's incentives, and for the most part goals, are to get a conviction by hook or by crook, and they will lie and cheat to get it.

Allow me to say first that I appreciate your extended comment even if I can't say I embrace all you've said in it. I can believe the personal experience you've described was, as you say, surprisingly stressful; but let's note that you came through it without, as I gather, either falsely confessing or changing your story. Every one of us lives with crime; every one of us lives with the possibility that, at any moment, he or she will be arrested for, or questioned about, a crime with which he or she has had nothing to do. Every one of us lives, as well, with the knowledge that some humans are liars; every one of us knows that that knowledge complicates interrogation. If any one of us is subjected to interrogation, he or she is obliged to perform seriously through it. That fact is no more subject to change than is, say, the law of conservation of energy. Either you accept it, meet your duties, and hold others to theirs--or you are antisocial.

This seems like an unfairly high standard to hold people to in order to determine whether they are "antisocial." After all, in an interrogation where the police do not believe the subject's protestations of innocence, they generally take extensive measures to induce the subject to change their testimony. Interrogation subjects can be subject to considerable duress, and condemning people for changing their stories under circumstances is, hopefully, different in degree, but is not different in kind from condemning people for caving to torture. It would certainly take an unusual definition of "antisocial" to capture people who will falsely self incriminate under sufficient pressure from the police.

As you know by now, I mentioned, below, that I'd got the impression that the multiple-attacker theory was insubstantial, but I do appreciate the time you've taken to detail problems with it. I'm not sure it's accurate to say the police walked into the case with a vested interest in tying Knox and Sollecito to it; but I can believe the police early on developed a theory of a many-party-attack and a false break-in to cover it, a theory they never managed to abandon.

In fact, the police flagged Amanda Knox as a suspect on the basis of her mannerisms at the crime scene, which the lead investigator (who has come under fire for his use of implausible profiling techniques in other cases) judged to be unusual, before developing a multiple-attacker hypothesis behind the murder. Raffaele Sollecito was flagged by association with Knox, as was Patrick Lumumba on the basis of her phone contact with him. All of this is a matter of public record. Since the presumption of Knox's involvement was central to their investigation from the beginning, they had a major reputational stake in not admitting that it had been based on weak premises, and all the information they received was thus evaluated in light of their original hypothesis.

As for your distinction between false confession and story-changing, the relevance of false confession here is simply that it is generally the most extreme form of story changing under duress from the police- false self incrimination. If people can regularly be induced to falsely self-incriminate, it should be no surprise if they can be induced to falsely incriminate others. The fact that Amanda Knox changed her testimony should be evaluated in light of the fact that she changed it to something that the police had known motive to pressure her for, and when she was removed from her conditions of duress, she immediately recanted. If we are to take this as evidence of anyone's wrongdoing, it should be that of the police, since we can take it as a measure of their misconduct that they convinced an interrogation subject to point them to a suspect that they had already decided they wanted, who we know in light of present evidence could not have been involved.

If you change your story, the probability of your guilt is 1.00. If one version of your story includes a false accusation (i.e., of another person), that goes up to 2.00

...and if your accusers are people who say things like the above, your probability of innocence is 10.00.

In all seriousness, you appear to be completely ignorant of the subject of coerced statements, as well as wildly overconfident about your ability to predict your own (not to mention other people's) behavior in highly abnormal situations. This, indeed, will make it difficult for you to understand the case for Knox and Sollecito's innocence.

If you change your story, the probability of your guilt is 1.00.

This is equivalent to stating "no innocent person ever changes their story." Empirically, this is false.

Let me provide a personal example. Several years ago, I was nearby when a co-worker was injured on the job. Two years later, I received a summons - she had ended up suing the company, and as an eyewitness, my testimony was relevant. Lawyers for the two parties asked me questions for a while; I answered to the best of my ability, as honestly as I could. My memory of the event was somewhat fuzzy by then, so I tried to only state things which I was sure I remembered accurately, and expressed my uncertainty when I was uncertain.

Once they finished their questions, they handed me a photocopy of a document in my own handwriting, written on the day of the event. The company had gotten such statements from everyone present on the day of the incident, you see. Not only had I forgotten that I had written such a thing until they showed it to me, my own handwriting directly contradicted the things I'd stated from memory minutes before!

This was before I participated in Less Wrong or was otherwise aware of the breadth of human cognitive failings. I was quite taken aback! My brain had betrayed me - not in old age, in my early twenties! I do not generally consider myself forgetful - if anything, I have an unusually good memory - yet in a fairly short span of time, my brain had managed to confabulate almost every detail of the event.

Since I became aware of it, I've noticed myself mid-confabulation on a regular basis. Despite how much my conscious mind values truth, my underlying hardware doesn't seem to much care.

You may indeed be one of the lucky people with flawless recall. This is not, by a long shot, a universal human trait. Memory is fragile. It is quite easy for many humans to misremember things without knowing anything has gone wrong, especially when under significant amounts of stress.

I know very little of the Amanda Knox case specifically, so this should not be taken as an argument for either side particularly. I am only arguing that your simple rule is not a good rule - it doesn't actually work.

Such a thing is extremely anti-social and is, I hope, criminalized itself.

I doubt that criminalisation would change much. Without having researched this, I would assume that people make false confessions when they believe they would be convicted even if they didn't confess.

I'm also not sure what's supposed to be so extremely antisocial about it. It's not like the police will surely catch the responsible party if only you don't make that false confession to get a more lenient sentence.

If you change your story, the probability of your guilt is 1.00. If one version of your story includes a false accusation (i.e., of another person), that goes up to 2.00

Well, one shouldn't be using such heuristics without prior research into the matter, precisely because of the typical mind fallacy. You couldn't imagine innocent people changing their stories - but it happens. So what does that say about the validity of your inference from your own imagination to the expected behaviour of other people?

If you change your story, the probability of your guilt is 1.00. If one version of your story includes a false accusation (i.e., of another person), that goes up to 2.00

At most you could convict them of something like obstruction of justice or criminal defamation, if you could actually prove mens rea beyond reasonable doubt.
But convicting somebody of murder just because they made an incorrect or even deliberately false claim, would not serve the interests of justice.

In this case, Knox was actually convicted of "calunnia" against Lumumba.
It could be argued whether this conviction was fair, since Knox made the claim in a statement signed at the end of a lengthy interrogation without an attorney, in a language she was not familiar with, and the statement mentions that she "remembered confusedly".
Anyway, fair or not, she already served her term for that false accusation.

Although no examples come to my mind, the storylines of many pieces of fiction, I think, turn on such story-changing, whose significance the author feels no need to explain.

Detective fiction isn't exactly known for its realism.

Komponisto translated what documentation was available to the public in Italy for people on this site to peruse. They're probably still linked on this or some related page, but if you're not invested enough to check them out yourself, I'll at least say that having spent a fair amount of time examining them during a protracted debate on the subject, I'd regard them as pretty damning to the prosecution.

Given some of your statements in this thread though, I think it might be a good idea (at least if you want to get an understanding of why people have been downvoting your comments,) to check out Privileging the Hypothesis and 0 and 1 Are Not Probabilities. Reading the entire How To Change Your Mind sequence would definitely give a better understanding of where people in this thread are coming from, but to be fair, it's pretty long.