# Can a human being beat a polygraph test?
**URL:** https://boards.straightdope.com/t/can-a-human-being-beat-a-polygraph-test/499542
**Category:** Factual Questions
**Created:** [June 12, 2009, 1:21pm UTC](https://boards.straightdope.com/t/can-a-human-being-beat-a-polygraph-test/499542 "2009-06-12T13:21:04Z")
**Posts on this page:** 12
**Page:** 2
### Author:  [@janeslogin](https://boards.straightdope.com/u/janeslogin)
#### Post date: [June 12, 2009, 6:04pm UTC](https://boards.straightdope.com/t/can-a-human-being-beat-a-polygraph-test/499542/21 "2009-06-12T18:04:09Z")
It seems to me that a much, much more important question is ‘Can the polygraph operators use the test to falsely incriminate me?’
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### Author:  [@HorseloverFat](https://boards.straightdope.com/u/HorseloverFat)
#### Post date: [June 12, 2009, 6:26pm UTC](https://boards.straightdope.com/t/can-a-human-being-beat-a-polygraph-test/499542/22 "2009-06-12T18:26:34Z")
Mythbusters isnt exactly a proper study. 3 tries with TV-friendly editing and personalities? Really now. Its entertainment first and education last. [These guys here have forgotten more about science, research, and metholodoly than all the mythbusters crew combined. They do not have a favorable view on polygraphs at all.](http://books.nap.edu/openbook.php?record_id=10420&page=212)
Not only are these machines inaccurate, they are dangerously inaccurate and can, and have been, abused by those in authority. The conventional wisdom of the polygraph today is as an interrogation tool. It stresses the usually uneducated criminal suspect to believe that the state has a window into his mind. Its just another tool in in bag of the unethical interrogator. Spreading the meme that they are ‘perfect’ is part of the charade.
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### Author:  [@Kobal2](https://boards.straightdope.com/u/Kobal2)
#### Post date: [June 12, 2009, 6:53pm UTC](https://boards.straightdope.com/t/can-a-human-being-beat-a-polygraph-test/499542/23 "2009-06-12T18:53:03Z")
> [@janeslogin](#):
>
> It seems to me that a much, much more important question is ‘Can the polygraph operators use the test to falsely incriminate me?’
That scares the hell out of me as well. The way I imagine it’d go (assuming I was innocent, obviously) would be :
1. I’m scared that polygraphs can’t tell shit from gravy
2. If the interrogators believe my gravy is shit based on the polygraph, I’m in deep, deep trouble
3. Profit !
No, wait, that doesn’t make sense.
3) baseline high stress (and I’m a nervous wreck at the best of times, too)
5) interrogator asks a particularly perceptive, sneaky, decisive etc… question
6) Stress level goes off the chart because I know that if I “flub” this question, I’m done for.
7) I’m done fo, as my high reaction is interpreted as a lie.
Combine that with the assumption, on the part of the jury who believes the false meme, that if I answer “no” to the question “would you be willing to take a polygraph test over it ?” it’s most probably because I’m lying…
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### Author:  [@Chronos](https://boards.straightdope.com/u/Chronos)
#### Post date: [June 12, 2009, 6:56pm UTC](https://boards.straightdope.com/t/can-a-human-being-beat-a-polygraph-test/499542/24 "2009-06-12T18:56:10Z")
Oh, they can be used effectively. If the suspect thinks it works, then he might give up and confess as soon as you say you’re using it. The thing is, though, it doesn’t have to actually work to get that effect: Stories are told of a police department getting a confession out of a perp using a fake lie detector they cobbled together out of a copier and a colander.
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### Author:  [@DocCathode](https://boards.straightdope.com/u/DocCathode)
#### Post date: [June 12, 2009, 10:37pm UTC](https://boards.straightdope.com/t/can-a-human-being-beat-a-polygraph-test/499542/25 "2009-06-12T22:37:19Z")
I was hooked up to pneumatrodes, Galvanic response sensors, photoplathysmagraph, and thermistors all the time (I was the newest employee) in order to demonstrate their utility in _detecting stress_. The boss, and most of the doctors who bought from us, could easily control everything the sensors read. I was convinced that polygraphs don’t work with spit to detect lies.
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### Author:  [@Skald\_the\_Rhymer](https://boards.straightdope.com/u/Skald_the_Rhymer)
#### Post date: [June 12, 2009, 10:44pm UTC](https://boards.straightdope.com/t/can-a-human-being-beat-a-polygraph-test/499542/26 "2009-06-12T22:44:53Z")
> [@RealityChuck](#):
>
> It’s not the machine – it’s the interpretation of the data. Different polygraphers can give different interpretations to the same set of data. It’s also much like N-rays – what you see can be biased by what you want to see.
Which is why **Philster** said he was using _polygraph_ to mean the entire process & system–that is, the machine plus the operator.
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### Author:  [@Skald\_the\_Rhymer](https://boards.straightdope.com/u/Skald_the_Rhymer)
#### Post date: [June 12, 2009, 10:47pm UTC](https://boards.straightdope.com/t/can-a-human-being-beat-a-polygraph-test/499542/27 "2009-06-12T22:47:32Z")
> [@Oakminster](#):
>
> Polygraphs are generally not admissable in court. Pretty much tells you all you need to know.
**Oak** , if I am accused of a crime and le gendarmes offer me the chance to take a polygraph, can they force me to do so? If I decline to take it, can the prosecutor mention that in court, or is such verboten, like drawing undue attention to the defendant’s declining to testify in his own defense?
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### Author:  [@Sage\_Rat](https://boards.straightdope.com/u/Sage_Rat)
#### Post date: [June 13, 2009, 2:17am UTC](https://boards.straightdope.com/t/can-a-human-being-beat-a-polygraph-test/499542/28 "2009-06-13T02:17:07Z")
> [@HorseloverFat](#):
>
> Mythbusters isnt exactly a proper study.
Well you can look at my other post, and note a link to some guys talking about a few dozen studies on thousands of people.
Ultimately, if someone can achieve a 90% rate consistently, it’s not obvious (outside of manufacturing data), how this can be due to a _mistake_ of methodology. What _bad_ methodology allows one to read another person’s mind?
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### Author:  [@Sage\_Rat](https://boards.straightdope.com/u/Sage_Rat)
#### Post date: [June 13, 2009, 2:18am UTC](https://boards.straightdope.com/t/can-a-human-being-beat-a-polygraph-test/499542/29 "2009-06-13T02:18:50Z")
> [@runcible\_spoon](#):
>
> Well, if he knows in advance that the Mythbusters are trying to lie and get away with it, being a fraud would certainly help him declare that the polygraph had caught them.
And the Mythbusters would have told him the correct results in advance for what reason? What evidence is there that they did so?
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### Author:  [@Oakminster](https://boards.straightdope.com/u/Oakminster)
#### Post date: [June 13, 2009, 4:42am UTC](https://boards.straightdope.com/t/can-a-human-being-beat-a-polygraph-test/499542/30 "2009-06-13T04:42:09Z")
> [@Skald\_the\_Rhymer](#):
>
> **Oak** , if I am accused of a crime and le gendarmes offer me the chance to take a polygraph, can they force me to do so? If I decline to take it, can the prosecutor mention that in court, or is such verboten, like drawing undue attention to the defendant’s declining to testify in his own defense?
At least in my state, you can’t be forced to take a polygraph in a criminal case. An employer can require a polygraph before or during employment, on pain of getting fired for refusal or failure. Then again, we’re an employment at will state, so you could get fired for wearing a loud tie if management was so inclined, barring contract or union protections.
Prosecutors will sometimes offer a polygraph, and agree to drop charges if you pass it. I’d advise against taking it anyway in most cases. Prosecutors can’t mention anything about a polygraph in front of a jury–whether one was offered, passed, failed, refused. That would be grounds for a mistrial, and likely sanctions as well.
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### Author:  [@runcible\_spoon](https://boards.straightdope.com/u/runcible_spoon)
#### Post date: [June 13, 2009, 4:56am UTC](https://boards.straightdope.com/t/can-a-human-being-beat-a-polygraph-test/499542/31 "2009-06-13T04:56:27Z")
> [@Sage\_Rat](#):
>
> And the Mythbusters would have told him the correct results in advance for what reason? What evidence is there that they did so?
Well, I haven’t even seen the episode in question, so I can’t say who told what to whom, but if the Mythbusters call you in to give them a polygraph, do you _think_ they’d be telling the truth? However, I don’t know anything about the circumstances of the test, so I’ll refrain from anything more definite.
As for the links you gave, one is from the American Polygraph Association, and will sell you their research for $25, one says that most of the scientists they talked to thought the polygraph was suspect, one says that the studies they looked at produced results ranging from chance to 100% success rates (which, I’d point out, is true of psychics, too), and one said that subjects taught a simple technique could fool the test 50% of the time.
Now, I’m not an expert, and I didn’t go into the data of any of those studies, but it’s hardly a slam-dunk case.
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### Author:  [@regginbrow](https://boards.straightdope.com/u/regginbrow)
#### Post date: [June 13, 2009, 5:15am UTC](https://boards.straightdope.com/t/can-a-human-being-beat-a-polygraph-test/499542/32 "2009-06-13T05:15:47Z")
> [@Chronos](#):
>
> Oh, they can be used effectively. If the suspect thinks it works, then he might give up and confess as soon as you say you’re using it. The thing is, though, it doesn’t have to actually work to get that effect: Stories are told of a police department getting a confession out of a perp using a fake lie detector they cobbled together out of a copier and a colander.
The Wire FTW!
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