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Re:Attempts to Censor AntiPolygraph.org by rightbyte on Saturday June 29, 2019 @06:30AM (#20311802)
"Lie detectors" are in practice a measurement of nervousity, right?

"Oh, his heart rate jumped when I asked what the end score was in the game he said he saw in his home at the time of the murder even though he gave the correct score maybe he guessed."

Re:Attempts to Censor AntiPolygraph.org by rndgermandude on Saturday June 29, 2019 @07:12AM (#20311928)
Not even nervousness per se.

If you get angry, it will "measure" that too, as a lie. Or if you get embarrassed, that "measures" as a lie. My grandma would have failed any cheater polygraph test horribly, as she turned red every time anybody mentioned anything related to sex in general. You could have asked her if somebody she never heard of had extramarital sex, and her answer, no matter what she said, would have showed up as a lie every time.

Physical or psychological exhaustion change the "results", too, of course. Or if you sit next to a window and the test takes long enough so that you start when you still sit in the shades but later the sun comes around and you sit in the light, that can be enough, too.

Or if you deliberately clench your anal sphincter, that's enough to change results. And yes, that actually works; that's why some lie detectors now feature ass-clenching detention technology.

Re:Attempts to Censor AntiPolygraph.org by EForEndeavour on Saturday June 29, 2019 @09:30AM (#20312448)
> that's why some lie detectors now feature ass-clenching detention technology

This is one of the most entertaining sentences I've ever read on this website.

Re:Attempts to Censor AntiPolygraph.org by api on Saturday June 29, 2019 @11:32AM (#20313129)
Sounds like psychopaths would do the best on these tests.
Re:Attempts to Censor AntiPolygraph.org by rndgermandude on Saturday June 29, 2019 @12:22PM (#20313389)
Not necessarily, but it's certainly not unheard of:

>In 2003, Gary Ridgway admitted he was the Green River Killer, having murdered 49 women in the Seattle area. Ridgway had passed a lie detector test in 1987, while another man - who turned out to be innocent - failed.

https://www.bbc.com/news/magazine-22467640

Re:Attempts to Censor AntiPolygraph.org by spiraldancing on Saturday June 29, 2019 @07:33AM (#20311997)
Lie detectors are a measure of heart rate, respiration, and galvanic skin response (roughly == how much you sweat).

What relationship—if any—those have to the truthfulness of a person at any given moment, remains debatable at best.

Re:Attempts to Censor AntiPolygraph.org by sneak on Saturday June 29, 2019 @03:09PM (#20314195)
There is no “debatable”: no correlation exists. Anyone who claims otherwise has to prove otherwise, and nobody has ever done so.

No correlation exists.

Re:Attempts to Censor AntiPolygraph.org by spiraldancing on Monday July 01, 2019 @12:31AM (#20322467)
And yet we appear to be debating.
Re:Attempts to Censor AntiPolygraph.org by aasasd on Saturday June 29, 2019 @07:31AM (#20311988)
In one of Cory Doctorow's books, the trick to cheat a lie detector is said to be to clench and unclench the anus repeatedly for several minutes (in advance before the test). Purportedly, this agitates the nervous system so the measurements hike up, and on this background your legitimate discomposure will look like smooth sailing. The anus is probably chosen just for the inconspicuousness.

Dunno how true this is and haven't heard of this trick elsewhere, though admittedly I haven't researched the topic. Other techniques in the ‘Little Brother’ books are real, apart from two or three that are doubtful to me.

Re:Attempts to Censor AntiPolygraph.org by Fjolsvith on Saturday June 29, 2019 @08:32AM (#20312212)
In the US, they use a sensor pad the subject sits on to detect such attempts to modify the results.
Re:Attempts to Censor AntiPolygraph.org by EForEndeavour on Saturday June 29, 2019 @09:32AM (#20312462)
I wonder if vividly picturing a cavalcade of ultraviolent mental images is enough to disrupt the test.
Re:Attempts to Censor AntiPolygraph.org by Fjolsvith on Saturday June 29, 2019 @10:01AM (#20312626)
Unfortunately, disrupting the test is the same as failing it. Typically, subjects are expected to pass it to avoid negative consequences.

I once went through a polygraph and used my meditative breathing techniques to calm my mind, and failed the test because I was "controlling my breath".

Re:Attempts to Censor AntiPolygraph.org by kevin_thibedeau on Saturday June 29, 2019 @12:39PM (#20313474)
I mostly belly breathe and have little upper chest expansion at rest. This caused some consternation during my test.
Re:Attempts to Censor AntiPolygraph.org by kofejnik on Saturday June 29, 2019 @12:27PM (#20313407)
I was subjected to a polygraph test once, and I successfully misled the operator several times, by slightly biting my tongue (so I was asked, "you show heightened emotional response to X and Y, something you're trying to hide?")
Re:Attempts to Censor AntiPolygraph.org by aj7 on Saturday June 29, 2019 @08:13AM (#20312134)
Exactly, you use all sorts of ways to screw up the baseline.
Re:Attempts to Censor AntiPolygraph.org by ap_org on Saturday June 29, 2019 @06:39AM (#20311839)
Polygraphs measure heart rate, breathing, and palmar sweating, which are affected by nervousness, but are not systematically correlated with lying. Voice stress analyzers don't actually measure stress in the voice.
Re:Attempts to Censor AntiPolygraph.org by 0815test on Saturday June 29, 2019 @07:01AM (#20311901)
Even worse than that, there are in fact plenty of people who will systematically fail to show nervousness when lying, or more generally in socially-stressful situations, viz. psychopaths (in a broad sense, including Dark Triad traits more generally). As it happens, their lies are incredibly easy to detect for other reasons (basically, they never keep their stories straight, especially since they like to embellish them with all sorts of fanciful details), but still, it's hard to imagine a more catastrophic failure of this whole "lie detectors as infallible" paradigm.
Re:Attempts to Censor AntiPolygraph.org by TazeTSchnitzel on Saturday June 29, 2019 @09:55AM (#20312584)
This video with a former FBI agent about how they interpret body language was interesting to me: https://youtube.com/watch?v=4jwUXV4QaTw

Lie detectors are basically like one of those body language tells. They don't tell you if someone is lying, but they can give you a hint as to how someone is feeling that might be useful in deciding what lines of questioning to pursue further.

Re:Attempts to Censor AntiPolygraph.org by derefr on Saturday June 29, 2019 @11:33AM (#20313130)
The goal of the use of a polygraph in witness interrogation during criminal investigation (its original purpose, separate from all this bunk about “passing” or “failing” polygraph “tests”) isn’t to get the information the interrogation needs from the polygraph, but rather to use that information to steer the interrogation toward whatever seems to most upset the witness, because that’s usually something they’d rather not be talking about (and ergo something that may have involved them committing a crime, moving them from “witness” to “suspect.”)

Of course, polygraphs don’t guide toward lies specifically, just toward uncomfortable subjects—which is why you hear about e.g. TSA screeners demanding to know if you were cheating on your wife, when that has nothing to do with things the TSA could care about. Whether or not they’re using a polygraph, the interrogation process involves digging for upsetting subjects; and so, if you have something upsetting you unrelated to the case at hand, they have to “dig it up” to “weed it out” of the interrogation, i.e. to put the way you’re reacting to questions about the subject they do care about in context. A witness who is very nervous because they’re off to visit their mistress, has had their nervousness “explained away”, and so being nervous is no longer suspect. (But other responses, like anger, still are leading. Being an interrogator requires recognizing differences in subtly-triggered emotions, because they usually have different sources. This is why so much was made of the power of “recognizing micro-expressions” back when, before that got mostly debunked.)

And, of course, it’s pretty easy to train someone to control a polygraph signal, and some people are even naturally “immune” to being read by one. Mindfulness meditation works pretty well to defuse most of the physiological responses to stressful stimuli, for example, and interrogators have no idea whether you’re doing it. It works even better—if you’re a professional spy and have some time on your hands—to just sit around hooked up to a polygraph, watching its output yourself, as someone tries to upset you. (The polygraph is, in this case, acting as a https://en.m.wikipedia.org/wiki/Biofeedback mechanism.)

Still, polygraphs were never intended to aid in the interrogation of professional spies; they were intended to be used like a drug-sniffing dog, to act as a quick heuristic to filter a large pool of “ordinary passers-by” (e.g. in a murder committed in a crowd) down to a few suspects who seem genuinely uncomfortable about something. Since most crimes aren’t committed by sociopaths, or Zen monks, or spies, but rather by people who think they have a momentary opportunity and usually regret their crime somewhat afterward, looking for discomfort tends to be fairly helpful in pre-filtering a large suspect pool; and using a machine that can detect “silent” discomfort is indeed an enhancement to that pre-filtering. (But, again, it’s only a pre filter. It’s a weak heuristic that needs following-up with further interrogation and detective work, to know whether to put these people on an actual suspects list. It’s common, when using such a heuristic, to filter some people in on the first pass, but filter every one of them back out in a second pass, and then realize you have to start from scratch with a different approach.)

And, of course, there are going to be departments who know none of this, whose understanding of the use of a polygraph comes from cop movies, but who go out and buy one anyway, ditch the highly suggested training offered by the manufacturer (or don’t get access to it because they’re buying the device used), and then do stupid pass/fail polygraph “tests” where “passing” the “test” is exclusionary, as if you had a non-matching blood type to the suspect’s blood or something. (And there are also departments who just use a polygraph—real or fake—as a prop to perform “enhanced interrogation.” Interrogation doesn’t need “enhancement” IMHO—it doesn’t even need a stern voice—but at least interrogation with a polygraph-prop isn’t literally a crime and an abridgement of human rights in the way some other “enhancements” are.)