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komponisto comments on The Amanda Knox Test: How an Hour on the Internet Beats a Year in the Courtroom - Less Wrong

42 Post author: komponisto 13 December 2009 04:16AM

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Comment author: komponisto 04 March 2011 03:57:58AM 1 point [-]

I'm ashamed to say I failed this one, and badly...this illustrates that I have a long, long way to go.

On the other hand, you'd be surprised at how difficult it is for people to understand this even after seeing the explanation. While of course it's always preferable to get things right on the first try, the fact that you saw it so clearly after reading this post places you in a high percentile for learning speed.

(I know whereof I speak here, because I've spent some time arguing about this in other parts of the internet, only to be dismayed by the true extent of people's ability to clack. Heck, even here in the comments section of this post there are some pretty confused comments with depressingly high scores.)

I think your analysis is excellent, and is an admirable example of "cognitive debugging". This part in particular is worth dwelling on:

Everything else was unreliable, and I did not treat it as such even though in my mind I even thought that it was unreliable.

It is really difficult for people to discount information, and to actually update on evidence of the form "that information may not be reliable", rather than treating it as an "opposing argument" to be rationalized away, or simply forgetting it altogether. Something like the bra clasp provides an example of this: people hear about it, and decide that Sollecito is guilty. Then, when they hear the defense argue that it's unreliable, they mentally dismiss it as "the defense trying to poke holes in the prosecution's case". They may respect the social obligation to provide some sort of answer to the defense's arguments, but they don't consider that the defense arguments should actually impact their belief about whether Sollecito is guilty; the belief-formation process was over and done with at the first stage!

It's not that they explicitly, consciously think like this, of course; rather, they have just failed to fully incorporate the "rules" into their unconscious belief-generating system. The third and fourth virtues are hard.

I like the star-gazing-at-noon analogy, and may use it myself in the future.

Comment author: bigjeff5 04 March 2011 05:07:27AM 2 points [-]

I think your analysis is excellent, and is an admirable example of "cognitive debugging". This part in particular is worth dwelling on:

Everything else was unreliable, and I did not treat it as such even though in my mind I even thought that it was unreliable.

That's what upset me the most. I made a special note of it, in order to give it a very low weighting, yet it was still a major factor in my assessment. It had to be, because the prosecution's case hinged on it.

I think next time I notice something like that I will have to assign it a specific weight as soon as I decide that it should be given a low weight. Instead I just labeled it as "weak" in my head and moved on.

So when I think "that's likely true" I should stop and consider what the actual number is that I would assign to it. This would help considering in spotting cases where I assign more than 100% total probability to an outcome. If I am thinking it is 70% likely that they are guilty and 60% likely that they aren't, there is an obvious problem. If I don't assign any numbers until I'm finished looking at the problem then I'll never spot this error, as I'll simply calculate not-guilty likelihood from the guilty likelihood.

Much to think about and much to learn still.