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SforSingularity 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: SforSingularity 27 December 2009 08:05:16PM 1 point [-]

I had heard about the case casually on the news a few months ago. It was obvious to me that Amanda Knox was innocent. My probability estimate of guilt was around 1%. This makes me one of the few people in reasonably good agreement with Eli's conclusion.

I know almost nothing of the facts of the case.

I only saw a photo of Amanda Knox's face. Girls with cute smiles like that don't brutally murder people. I was horrified to see that among 300 posts on Less Wrong, only two mentioned this, and it was to urge people to ignore the photos. Are they all too PC or something? Have they never read Eckman, or at least Gladwell? Perhaps Less Wrong commenters are distrustful of their instincts to the point of throwing out the baby with the bathwater.

http://www.amandadefensefund.org/Family_Photos.html

Perhaps it is confusing to people that the actual killer is probably a scary looking black guy with a sunken brow. Obviously most scary looking black guys with sunken brows never kill anyone. So that guy's appearance is only very weak evidence of his guilt. But wholesome-looking apple-cheeked college girls don't brutally murder people ever, pretty much. So that is strong evidence of her innocence.

Comment author: Eliezer_Yudkowsky 27 December 2009 08:27:31PM 7 points [-]

Girls with cute smiles like that don't brutally murder people.

[citation needed]

Comment author: gwern 27 December 2009 08:37:34PM 7 points [-]
Comment author: Bo102010 27 December 2009 10:44:33PM *  1 point [-]

Although "unattractive individuals commit more crime in comparison to average-looking ones, and very attractive individuals commit less crime in comparison to those who are average-looking" is evidence for SforSingularity's claim, his comment is absurd enough to be taken as satire.

Comment author: gwern 28 December 2009 12:53:24AM *  9 points [-]

It's clearly absurd to say that pretty girls never murder people. But allowing for the normal hyperbole and inexactitude of conversational English, I don't think that's what SforSingularity means, rather, 'pretty girls are one of the demographic least likely to be responsible for a brutal murder'.

This isn't too unreasonable.

  • First off, the number of murders so ascribable are small: females make up half the population and if we limit pretty to the top 5% or so (a reasonable guess at % for 'pretty enough that a guy will actively note and think "pretty!"'), we're already down to less than 2.5% of the population.
  • Second, women in general commit far fewer violent crimes than men. http://www.ncjrs.gov/html/ojjdp/jjbul2002_10_1/page4.html mentions that for juveniles, at one point, the male:female ratio was 22:1. Let's be conservative and put the young adult ratio at 5:1; now we're down to 0.4%.
  • Third, attractiveness is correlated with IQ, and IQ is well-known to correlate with lower crime rates. (see Wikipedia for a few links; IIRC, WP understates the case but I can't be fashed to dig up the stronger correlations). Let's cut another 10% off the rate, down to 0.36%.
  • Fourthly, attractiveness correlates to higher socioeconomic status through multiple mechanisms, which cuts down violent crime even further. (I don't think I need to adduce any citations for that!)

And so on. I've missed many factors (eg. maybe happier & less stressed people are more attractive, and that too is correlated to less propensity for murder; maybe pretty women have fewer violence-inducing mental diseases and substance abuse habits; etc.). But I've already knocked their murder rate way down. I suspect it has much further to go in a true reckoning.

Does his comment still look satirical to you?

Comment author: DanArmak 28 December 2009 12:33:06PM *  5 points [-]

we limit pretty to the top 5% or so (a reasonable guess at % for 'pretty enough that a guy will actively note and think "pretty!"')

Interesting. When I read "pretty", I thought of a binary division (make guys judge "pretty or not") and I thought it would yield at least 30-40% as pretty. (Possibly much more, but I've a high degree of certainty that at least that much.)

Granted that your test is different than mine, what leads you to your 5% estimate, which looks low to me even with your test?

Comment author: Jack 28 December 2009 12:42:21PM *  5 points [-]

30-40% seems reasonable for Knox's age group (early twenties). Something closer to 5-10% seems reasonable for the entire female population. Keep in mind pretty people are almost certainly more visible than the non-pretty (especially if you have high socio-economic status).

Comment author: gwern 01 January 2010 11:20:43PM 1 point [-]

I think 30-40% is unrealistic: something like 20-30% of females in that age group are overweight or obese, leaving 70-80% in an attractive weight bracket; are we really going to call half of those 'pretty'?

It may just be my media-biased high standards, but I don't think I'd call half of all thin young women that.

Comment author: DanArmak 28 December 2009 12:56:36PM 0 points [-]

Right... I was a fool to miss that. You're perfectly right of course.

Which leads us to the question of what "natural category" to put Knox in. Should it be "a pretty woman out of all women" or "a pretty young woman out of all young women"? Or lots of other options, of course. (We use some category the moment we compare her to women and not to all humans.)

But I'm sure this has been discussed, I haven't read all of this subthread...

Comment author: gwern 28 December 2009 02:12:03PM 1 point [-]

Here's one exercise: take your highschool yearbook, open one of the dense pages (with dozens of pics on it), and let your eye drift along the columns with no particular intent (this is hard); how many of the girls will actually catch your attention for being attractive and not for having, say, bizarre & outdated hairstyles? For me, it was less than 1 in 10. (One plain forgets about the bottom 50% and between that and 90% is the 'unoffensive' range.) Considering that my highschool was private and that selection effects were already operating, I have to revise the estimate further down; ~5% seemed good & is a nice round number.

Comment author: Technologos 28 December 2009 03:47:49PM 4 points [-]

For what it's worth, I remember a study on Stanford undergrads with what was essentially speed dating; men suggested their interest in a second date with ~90% of the women they met, and simultaneously their top criterion for that choice was attractiveness. Even granting that they had loose definitions caused by the study, I suspect that under Dan's metric (binary choice) a reasonably large minority might be tagged "pretty."

I also didn't get the impression from the photos on the website that anybody in the Knox case was pretty in the sense that you mean it--I think of your criterion as defining "remarkably pretty" rather than "pretty, if I had to choose," and I'd say you're probably right on <5% being remarkably pretty.

Comment author: Douglas_Knight 28 December 2009 09:22:41AM 3 points [-]

First off, the number of murders so ascribable are small: females make up half the population and if we limit pretty to the top 5%..., we're already down to less than 2.5% of the population.

That's like saying very few murders are committed by people named Amanda. That's OK, if you're very careful, but you have to, at least, weigh it against the very few murders by people named Rudy. 2-4 are OK, though.

Comment author: gwern 03 April 2013 06:00:51PM 0 points [-]

Reference class tennis. Being an attractive female with a (formerly) well-off family is far more important a reference class than being named Amanda; and the corresponding reference class for Rudy would be being an unattractive man who is a poor African immigrant.

Comment author: Douglas_Knight 03 April 2013 11:44:24PM 1 point [-]

Reread your comment. What is the point of your your first bullet point that pretty girls are rare? That tells you nothing, just as the fact that Amandas are rare tells you nothing. Points 2-4 about the relative propensity to murder are relevant. But I'm explicitly talking about point 1 in isolation.

Comment author: gwern 03 April 2013 11:53:42PM 0 points [-]

What is the point of your your first bullet point that pretty girls are rare? That tells you nothing, just as the fact that Amandas are rare tells you nothing.

Yes, it does. If there is any sort of inverse quasi-linear relationship between prettiness and propensity to murder, as one would expect, we would expect the reduction in murder rates compared to the average to be the largest at the extremes - that is, for rarely pretty girls we will expect rarely large effects.

Comment author: Douglas_Knight 04 April 2013 12:18:20AM 0 points [-]

That's not how you used it in your post. Seriously, just read your post. What do these numbers mean?

Comment author: Bo102010 28 December 2009 01:14:46AM *  1 point [-]

I think the "My probability estimate of guilt was around 1%" bit is probably pretty spot on (for the reasons you state), and not absurd.

I think the "I only saw a photo of Amanda Knox's face. Girls with cute smiles like that don't brutally murder people" and "Perhaps it is confusing to people that the actual killer is probably a scary looking black guy with a sunken brow" bits are absurd-enough-to-be-satire.

Comment author: Alicorn 27 December 2009 08:26:31PM 5 points [-]

Via what mechanism does wholesome appearance and apple-cheekedness correlate with a disinclination to commit murder? For example, does a murderous disposition drain the blood from one's face? Or does having a cute smile prevent people from treating the person in such a way as to engender a murderous disposition from without? I wouldn't be exactly astonished to find a real, strong correlation between looking creepy and being dangerous. But I'd like to know how it works.

Comment author: SforSingularity 01 January 2010 02:28:44PM *  6 points [-]

Think about it in evolutionary terms. Roughly speaking, taking the action of attempting to kill someone is risky. An attractive female body is pretty much a guaranteed win for the genes concerned, so it's pointless taking risks. [Note: I just made this up, it might be wrong, but definitely look for an evo-psych explanation]

This explanation also accounts for the lower violent crime rate amongst women, since women are, from a gene's point of view, a low risk strategy, whereas violence is a risky business: you might win, but then again, you might die.

It would also predict, other things equal, lower crime rates amongst physically attractive men.

Comment author: Jack 29 December 2009 09:03:34AM 3 points [-]

One of the comments about the photos was mine I believe. I tried to avoid the photos of both Knox and Kercher (though I failed spectacularly). The fact that Knox is pretty and has a cute smile is worth updating on, perhaps. But for me it would be better to be told those facts rather than figure them out by staring at pictures. Millions of years of evolution have made attractive girls my age more bias inducing than just about anything else in my life. For the lonely I imagine the effect is considerably more dramatic. Surely we don't think the men who wrote Knox letters telling her how beautiful they thought she was are seeing things clearly and objectively.

And everyone is programmed to have their protection instincts kick in on the sight of a young, baby- like face (this is why the facial expression of fear resembles the face of a baby).

Comment author: RonnyRaygun 10 January 2010 09:02:49PM *  1 point [-]

Hello, everyone, my first post, and while I'm not sure it will be seen as entirely rational, here it is anyway :)

I don't know if attractive girls of Amanda Knox's age are more bias inducing. I would tend to think that cute faces do make people feel a certain protective, nurturing instinct. I also think, however, that SforSingularity has a point. I haven't seen any evidence to back it up, but I believe it is rare for "cute" girls to commit violent murder without severe provocation. That's not to say it doesn't happen.

From personal observation, it seems that people who look agressive are more likely to be agressive. Would this be due to the balance of testosterone / oestrogen in the womb, throughout childhood and adolescence, and into adulthood? It would be interesting to find out if studies have been done to prove or disprove this theory. Also, I certainly believe that the above assertions appear to be true in the animal kingdom. Agressive looking animals, almost without exception tend to be more agressive predators. We, both as individuals and as a species, are animals so I see no reason why the same shouldn't apply to us.

Finally, I recently read a study concerning the domestication of dogs. Dogs are known to have evolved from wolves (they can still interbreed very sucessfully) and the hypothesis was that humans selected the most docile wolves and bred them, as they would make better companions and would be easier to train.

To test this, a study was carried out on Russian Silver Foxes. For the last fifty years the most docile foxes have been selectively bred. The current generation is now incredibly docile, and actively seeks out human companionship, but more importantly, they look cute (i.e. they bring out a protective, nurturing instinct in their carers), and show little agression towards people or other animals.

Finally, I don't think any of the above has any bearing on the guilt of Amanda Knox. I am still absolutely amazed that a jury could have convicted her and Sollecito guilty based on the evidence provided.

Comment author: mattnewport 10 January 2010 09:23:18PM 2 points [-]

From personal observation, it seems that people who look agressive are more likely to be agressive. Would this be due to the balance of testosterone / oestrogen in the womb, throughout childhood and adolescence, and into adulthood? It would be interesting to find out if studies have been done to prove or disprove this theory.

I don't know of any studies specifically on aggression but this recent study found evidence that people are able to make significantly better than chance personality judgements based on a single photograph.

Comment author: ideclarecrockerrules 10 January 2010 09:29:46PM 2 points [-]

Signaling may play a significant role in this.

Comment author: orthonormal 16 January 2010 03:43:54AM 0 points [-]

As may microexpressions and other things of which we're not often consciously aware. This doesn't go to the level of a single photograph, but the (badly-named) truth wizards can "observe a videotape for a few seconds and amazingly they can describe eight details about the person on the tape."

We communicate more than we think.

Comment author: lispalien 25 March 2010 06:22:23AM 0 points [-]

I followed this link, and found the blog of one of the "truth wizards" from the study. She writes about the Amanda Knox case. It seems to entirely focus on Amanda Knox.

Comment author: komponisto 25 March 2010 05:44:06PM *  5 points [-]

This has been mentioned before; I'll reiterate my reaction in more detail here.

First of all, there is very little "Truth Wizard" analysis of Amanda Knox on that blog (whatever one thinks about the strength of such evidence in the first place). There are several posts about the case, but in only one of them does the author actually attempt to apply her own "lie-detecting" skills to Knox. (In particular, the most recent post on the case just consists of the author's commentary on someone else's argument that Knox is a sociopath; contrary to orthonormal, there is no claim by the author that she herself has detected sociopathy.)

The one post where the author does analyze Knox concerns her statement at Guede's trial, of which only audio (not video) is available. (Of Knox's videotaped testimony at her own trial, the author says: "...without hearing the questions asked of Knox, it is impossible to identify if she is lying." -- emphasis added.) Thus, there is no data about facial expression, which is apparently an important component of the author's technique. Hence confidence in this analysis must be presumably be lowered from what it would be if the author were working from a video recording.

But in any case, the reasoning in that post is awful. To the extent the author is skilled in detecting lies, she is obviously not particularly skilled in explaining how she arrives at her conclusions. Here is an example:

Does this make any sense? She couldn't remember because she was tired? It was the middle of the night? Does anyone believe this is a good reason for a lack of all memory? When Amanda is telling us this, a year has passed from the crime, so why doesn't she elaborate more in this statement? Why isn't she setting the record straight for the judge here and now?

The author seems to be expecting Amanda's memory of an incident to improve over time. Now, I'm not an expert on memory, but this is directly contrary to my understanding of how it works. In fact, (to invoke my own memory here) I distinctly recall Eliezer mentioning once that memories are re-created each time we remember something. If this is true, it implies that memories -- even if they become more vivid! -- would become less entangled with reality over time, not more; which is anyway what you would expect from....physics.

Here is another, well, "red flag", concerning Knox's account of being hit on the back of the head by a police officer:

So, what ended up happening was.... the fact that I had been pressured so much, and I was....(sigh), I was hit in the back of the head by one of the police officers...who said she was trying to make me...help me remember the truth.

She was pressured so much that she was hit on the back of the head? Does that make sense? Why does she change "make me" which is a strong statement to "help me", which is much softer? I find this odd. If someone is hitting me on the back of the head, they aren't "helping me" do anything. They are making me forcefully and brutally react. Why aren't her emotional memories matching her story?

The author completely misses the obvious interpretation (in the absence of prejudice), which is that the phrase "make me" reflected Amanda's emotional interpretation of the situation, but that she corrected it to "help me" in order to more accurately recount what the officer(s) actually said!

This kind of shoddy reasoning is, I regret to say, characteristic of the author's (rather limited) discussion of the case. Whatever truth-detecting skills she may possess, I don't think her posts have provided us with very much useful information at all.

Finally, I will point out that the author (who by the way links to True Justice but not to any pro-Knox site) claims not to have made an incorrect judgement in 5 years...and yet now lists this case among her "successes"! Obviously, that's more than a bit problematic. (It should be noted that not only is the appeals process ongoing, but the conviction only intensified the controversy, if anything.)

Comment author: komponisto 16 January 2010 03:58:07PM 0 points [-]

Link (1:44) for those interested in trying the video experiment on themselves in the present context.

For a much more extended sample, see here.

Comment author: Jack 10 January 2010 09:44:39PM 1 point [-]

Welcome! Feel free to introduce yourself here.

Comment author: DanArmak 10 January 2010 10:24:53PM 0 points [-]

my first post, and while I'm not sure it will be seen as entirely rational [....]

And then:

I haven't seen any evidence to back it up, but I believe [doesn't matter what exactly....]

Belief without evidence - that's irrationality, right there. You may be misunderstanding the meaning of "evidence" - especially as that word is used in this community.

Comment author: Jack 10 January 2010 10:32:46PM 0 points [-]

I assume he means studies or 'scientific' evidence (as if there were some other kind).

Comment author: DanArmak 10 January 2010 10:39:22PM 0 points [-]

The other kind is rational (Bayesian) evidence. That's what most people here mean by unqualified "evidence", I think.

Comment author: Jack 10 January 2010 11:02:36PM 0 points [-]

Scientific evidence is Bayesian evidence, no? I was just implying that I didn't think there was a special category of evidence gathering delimited as 'science'.

Comment author: Technologos 10 January 2010 11:14:37PM 0 points [-]

Best I can tell, Science is just a particularly strong form (/subset) of Bayesian evidence. Since it attempts (when done well) to control for many potentially confounding factors and isolate true likelihoods, we can have more confidence in the strength of the evidence thus obtained than we could from general observations.

Comment author: Jack 10 January 2010 11:28:57PM 0 points [-]

Yeah, though a lot of science is just building localized, domain specific ontologies (here's what kinds of fish there are, here's what kind of stars there are etc.) and I'm not sure this kind of scientific knowledge is much better than observations you or I make routinely. Also, some evidence gathering is every bit as powerful as science (or more so) and yet is rarely counted as a science ( advanced sports statistics or marketing studies for example).

Comment author: komponisto 29 December 2009 07:11:09AM 1 point [-]

My probability estimate of guilt was around 1%. This makes me one of the few people in reasonably good agreement with Eli's conclusion.

As far as I am aware, all we know about EY's number is that it is bounded from above by 15%.

Since the average estimate was 35% (and that was before this post, after reading which some people said they updated downward, and no one said they updated upward), it's fair to say a lot of people were in reasonably good agreement with EY's conclusion.

Perhaps Less Wrong commenters are distrustful of their instincts to the point of throwing out the baby with the bathwater.

I don't know whether SfS's comment is to be taken as attempted satire or not, but I did wonder if a sort of "Spock bias" might result in reluctance to update on the sort of evidence presented here or here. As it turned out, that didn't seem to be so much of an issue here on LW (for all that character assassination of Amanda played a role in the larger public's perception). By far the biggest obstacle to arriving at probability estimates close to mine was that old chestnut: trusting in the fundamental sanity of one's fellow humans. (The jury must have known something we didn't, and surely Judge Micheli knew what he was doing...)

Comment author: Eliezer_Yudkowsky 29 December 2009 08:32:45AM 2 points [-]

The idea was that anything over 15% was wildly unreasonable.