
 Finding Sociopaths on Facebook - anu_gupta
http://www.schneier.com/blog/archives/2013/06/finding_sociopa.html
======
DanBC
An excellent post by Schneier.

> The problem isn't just that such a system is wrong, it's that the
> mathematics of testing makes this sort of thing pretty ineffective in
> practice. It's called the "base rate fallacy." Suppose you have a test
> that's 90% accurate in identifying both sociopaths and non-sociopaths. If
> you assume that 4% of people are sociopaths, then the chance of someone who
> tests positive actually being a sociopath is 26%. (For every thousand people
> tested, 90% of the 40 sociopaths will test positive, but so will 10% of the
> 960 non-sociopaths.) You have postulate a test with an amazing 99% accuracy
> -- only a 1% false positive rate -- even to have an 80% chance of someone
> testing positive actually being a sociopath.

Interestingly here he uses percentages to describe base rates and risk. Gerd
Gigerenzer has a nice book, _Reckoning with Risk_ , where he explains with
many examples the problems of this approach. Gerd asks people to use real
numbers instead, which are much easier to understand for most people.

Thus, Schneier's example becomes:

> _Out of 1,000 people about 40 of will be sociopaths. You have a test that
> will tell you if someone is, or is not, a sociopath. The test will be
> correct 9 times out of 10. Bob has taken the test, and has been identified
> as a possible sociopath. The chance that Bob is actually a sociopath are
> actually about 1 in 4. This is because the test will tell you that 36 of the
> 40 sociopaths are sociopaths, but it will also incorrectly tell you that 96
> non-sociopaths are sociopaths._

My writing is lousy, and other people will be able to clean this up, but even
with my poor writing style it's easier for most people to follow and
understand than the percentages.

This is alarmingly important when you're making a health decision - "Should I
remove my breasts to reduce my risk of breast cancer?" for example.

([http://www.amazon.com/Reckoning-Risk-Learning-Live-
Uncertain...](http://www.amazon.com/Reckoning-Risk-Learning-Live-
Uncertainty/dp/0140297863))

EDIT: I use "sociopath" because it's in the source article. I agree with NNQ
that it's very troubling to bandy around diagnostic labels like this, and deem
people to be dangerous, just because of a tentative probabilistic diagnosis.

~~~
coffeemug
This is a pretty bad example to illustrate the fallacy because a 25%
confidence is actually _extremely_ good. I don't know what good a test for
sociopathy is, but if we had a test this good at identifying terrorists, it
would be incredibly useful. If signals intelligence could produce a list of
people and guarantee that a quarter of the people on that list are terrorists,
it would absolutely revolutionize law enforcement.

~~~
paganel
> and guarantee that a quarter of the people on that list are terrorists,

Honest question, what would happen to the other three quarters?

~~~
anigbrowl
Most likely nothing. It depends on what sort of test it is; if it's something
non-intuitive like (say) a habit of writing sentences that always have a prime
number of words in them, you'll get your false positives but most those people
won't pass any other tests, whereas the actual terrorists will.

What Schneier is missing is that while you can't ID people that well from a
single test, you can apply a bunch of them. In his example, one test improves
the probability of correctly ID a sociopath from 4% to 24%. Apply another,
different test of similar efficacy to that result set and you'll have a
population of 21 true positives, and 8 or 9 false positives, increasing the
probabiliy of a successful ID from 25% to ~70%. Sure, there's no single test
that will give you reliable answers, but so what? It's OK to use a multi-
pronged solution.

~~~
bandushrew
Waiting until someone actually commits a crime provides a list that is 100%
accurate.

~~~
anigbrowl
No, it doesn't. People commit crimes and get away with them al the time, in
fact. I'm not proposing that we put people in jail for having criminal
potential.

~~~
bandushrew
Nothing that is being proposed will stop people getting away with crimes.

Waiting until someone actually commits a crime will stop people being
persecuted for a coincidental similarity of their behavior to that of a
terrorist, sociopath or mime artist.

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codex
The "fallacy" described here is a non-issue. Medical tests have the same
characteristics but are still incredibly useful. HIV testing is roughly 99%
accurate, but given the large number of tests performed, a very large
percentage of people will end up with the wrong result. And yet this test is
vital.

Even wildly inaccurate tests can be useful. Imagine that driving drunk will
result in a accident 10% of the time. 90% of the time, however, a driver will
make it home safely. This is a wildly inaccurate predictor, but it still
critical to know someone's blood alcohol level before giving them their keys.

One must simply be aware of the uncertainty involved in any test, and treat
test results as probabilistic signal, not as proof.

~~~
DanBC
I tend to agree with you, except it is not a non issue.

Look at the numbers of people getting very serious medical treatment because
they, and their clinicians, have not understood the numbers.

If doctor (well educated intelligent person) cannot get this right I'm scared
that labelling someone as "POTENTIAL TERRORIST" on the basis of a 1 in X
possibility is going to have disastrous consequences.

~~~
_delirium
Yes, this is an active area of debate in evidence-based medicine (EBM). If you
aggregate outcomes, administering some tests actually appears to worsen
prognosis, in the sense that if you take two groups of people with identical
distributions of (unknown) conditions, and test one group while not testing
the other, the tested group has worse overall outcomes. For example, in some
cases people have surgery for a condition that, absent the test, would have
remained asymptomatic and benignly ignored. With certain kinds of conditions,
negative outcomes from retrospectively unnecessary treatment are frequent
enough to outweigh the cases where discovery and treatment improves outcomes,
if we're talking about aggregate outcomes.

Of course, discovery does not require treatment, so you could test, find a
positive, and not do anything. But EBM people tend to view idealized responses
with suspicion, and some argue that taken in real-world conditions, not
administering certain tests, or administering them in more restricted
situations, or at least not recommending them as the default, would improve
aggregate outcomes (and the data seems to support that). They would then
restrict the tests to cases where testing statistically improves outcomes.

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nnq
Being "positive on a sociopathic personality test" does now equal being "a
potentially dangerous pathological sociopath"!

Even if you get a system good enough to overcome the base rate problem, you'll
only end up labeling a bunch of mostly harmless people. Think a about a
hypothetical uber-villain that would want to recruit children or teenagers,
brainwash them and turn them into assassins or other kind of agents. He may
find out that people with _some_ sociopathic traits are better candidates for
this, so he will target them. Now think the uber-villain is, uhm... (working
for) your government :)

...not to mention the mislabeling of people with atypical social interaction
patterns, like ones with mild/pseudo aspies which combined with the base rate
fallacy brings serious mislabeling.

I'm sure this kind of electronic-psycho-profiling is already in use, and I
even think it may have interesting side-benefits, like cool work being done in
AI research for use in this (no better way to start "humanizing" and AI than
to have it model human personalities and predict their actions), but there's
tons of things that can go south with it for lots of innocent people that just
happen to be "different" (like most people who end up making breakthrough
discoveries or world changing inventions, you know...).

~~~
hrktb
Agreed. And perhaps the notion of "dangerous sociopath" can be revised
altogether. I'm no expert but in my understanding sociopathy is more about non
empathic social behavior. It can be felt as creepy and depicted as violent in
fiction, but that's doesn't make it a dangerous behavior in itself, and can
actually be socially rewarded.

It can be argued that the lack of empathy can lead to a more violent behavior,
but violent acts comming from deep personal relationship are plenty a dozen as
well, who knows.

~~~
jbondeson
The problem here is that people are using a term that has a long and colorful
history in a very imprecise manner. Sociopath hasn't been in the literature
for years, but people still seem to use it interchangeably to speak of
antisocial behavior and/or psychopathic traits which are not at all
interchangeable.

The DSM doesn't even list psychopathy as a diagnosis any more, only antisocial
personality disorder which requires a history of, and we might as well just
quote the DSM "... a pervasive pattern of disregard for, and violation of, the
rights of others..." So yes, a diagnosis of ASPD does generally indicate
someone who could be considered dangerous to others.

Now if we're talking about someone with psychopathic traits that scores high
on a Hare, then no it does not necessarily indicate dangerous behavior.
However, a Hare is still important when dealing with criminals as you do not
want to give a psychopath treatment as it simply makes them _better
criminals_.

~~~
nnq
> you do not want to give a psychopath treatment as it simply makes them
> better criminals.

What do you mean by "treatment" in this context? I thought that caught
psychopathic criminals can end up in criminally insane facilities and such in
most developed countries and somehow treated or at least attempt to do so.

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michaelfeathers
Bruce has a great point about how people overreact due to the base rate
fallacy, but I'm afraid that it will forever be too subtle for legislators and
judges.

My immediate thought is that if the base rate fallacy were part of their
education, society would be better off, but legislators still have to play to
their constituents and it's hard to have hope in that sphere.

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shubb
I'm expecting social networks to be used 'voluntarily' for insurance soon.
Likely the no social network quote will be higher, because it's higher risk
because it's based on less information.

So you get a quote through their app, which uses your likes, your social
network, and maybe some NLP on your posts to decide if you qualify for a lower
quote.

Insurance people in the UK tell me this would be very useful, but probably
isn't possible from a legal perspective, but there will be other countries
where it is.

An effect of this would be to penalize people who don't use social networks.

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swamp40
What happens if the "terrorist" is a normal person who loves his family and
his country, and believes his sacrifice is honorable?

"Even bad men love their mommas." \- Ben Wade (Russell Crowe), 3:10 to Yuma.

~~~
honzzz
I doubt that 'normal people' would be able to commit terrorist attacks because
normal people experience empathy which would prevent them from hurting people
voluntarily (even soldiers who act under strict orders in a war that is
perceived as just are often traumatized by hurting/killing an enemy
combatant... and this would be much more severe if victims were known to
include innocent people or even children).

The problem is that there is always enough people who are not normal (there is
a great book about it by Erich Fromm: The Anatomy of Human Destructiveness)
and it's possible to 'make' people into something not normal in psychological
sense - i.e. suppress their empathy for certain group of people by some war
trauma or conditioning/brainwashing.

BTW, I think that it's a myth that even bad men love their mommas. It depends
how you define love. From what I remember based on one psychopath that I know
really well he claims that he loves his mother and maybe he even thinks he
feels something like that but he acts in such a way that his mother often gets
hurt by his actions and he acts with complete disregard of that. Not love in
my book.

------
msg
Here's the real problem: suppose you have a bunch of data on people and are
convinced that somewhere in the data exists the spectrum from sociopath to
non-sociopath.

Who is going to label the data with ground truth? Clinicians who "know it when
they see it"? What is the ground truth that the classifier is going to train
on?

If you're going to do an unsupervised classifier (eg clustering) who is going
to label the clusters? What is going to keep the data from turning into
uncorrelated mush?

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MaxScheiber
Two words: Bayes' theorem. I think I learned this in the fourth or fifth week
of my first probability course. Thought it was a bit more commonly known.

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squozzer
I think the word "sociopath", like "nihilist" and to a lesser extent
"traitor", never had much meaning outside of "someone whose characteristics or
actions I do not like".

So I question the basis on which Mr. Adams -- whose works some might consider
a sociopathic attack on American business practices, and by extension,
capitalism -- thinks content analysis is a good idea.

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fortepianissimo
Accuracy is known to be a unreliable metric to measure the quality of a test
(classifier). One paradox is that tests of higher accuracy might have less
predictive power than the one with lower accuracy.

[http://en.wikipedia.org/wiki/Accuracy_paradox](http://en.wikipedia.org/wiki/Accuracy_paradox)

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trimbo
If you are interested in this subject, check out "The Sociopath Next Door". It
changed my perspective quite a bit.

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ColinDabritz
Unfortunately the standard isn't even a lackluster 80%. We've learned that the
'go to' standard is 51%.

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fortepianissimo
I'm sorry, but 36/(36+96) = 27.27%.

~~~
EliRivers
Well, at least you're sorry about it. Try not to do it again :)

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isaacb
I hate that the author is using terrorist and sociopath interchangeably

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fredBuddemeyer
moralism is irrelevant in the face of producing simple intelligence. bet on
it, prohibition is futile. it can serve good as well.

------
gundy
In other news psychiatry is bullshit and I would say psychology is not far
behind. The whole point of society is that we don't assume people are a
certain way until they harm someone. If we no longer do that we're no
different from any of the other totalitarian regimes and religions that
prescribe their own flawed dogma about what constitutes a flawed person
deserving to be punished. Any such civilization should be overthrown because
it runs counter to all ideals of the enlightenment.

[http://blogs.scientificamerican.com/cross-
check/2013/05/04/p...](http://blogs.scientificamerican.com/cross-
check/2013/05/04/psychiatry-in-crisis-mental-health-director-rejects-
psychiatric-bible-and-replaces-with-nothing/)

------
androidb
There's nothing wrong with being a sociopath as long as you follow Harry's
code.

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jokoon
I really doubt sociopaths would use facebook at all anyway

~~~
Samuel_Michon
Perhaps you’re thinking of people who are antisocial? I wouldn’t be surprised
if some of the Facebook members who are most active and have the most
‘friends’ are sociopaths.

~~~
jokoon
I have no real idea. I was just saying this, as in, I don't think criminal
hang around facebook.

If that'd be the case, would facebook just be some sort of crime catching tool
?

I wonder though, is sociopathy a crime, or some trait that will turn people
into criminal ?

> I wouldn’t be surprised if some of the Facebook members who are most active
> and have the most ‘friends’ are sociopaths.

I doubt the people you are talking about can be criminal.

Crime and psychology, _sigh_

~~~
Samuel_Michon
I’m not talking about crime. Most sociopaths never commit any crimes and it’s
not illegal to be a sociopath. That would be silly, like jailing someone for
having red hair. Also, it’s quite possible that there are more sociopaths than
there are people with red hair – estimates range from 1% to 4% of the
population.

> I don't think criminal hang around facebook.

Are you sure about that?

~~~
jokoon
I just don't see where the correlation between sociopathy and crime comes
from.

~~~
Samuel_Michon
There’s a correlation, but one can’t say ‘All sociopaths are criminals’, just
as one can’t say ‘All drug addicts are thieves’.

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hownottowrite
On Facebook, you don't find sociopaths -- sociopaths find you!

