why arent lie detector tests used in court?

Discussion in 'Off Topic' started by Corporate Thug, Jul 16, 2003.

  1. Corporate Thug

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    i know they arent full proof but they are pretty accurate, so why dont courts use them more often and include it as part of the defense or prosecution. i'm not saying use a lie detector test and use that alone to render an innocent or guilty verdict, just include it as part of the testimony
     
  2. Garet Jax

    Garet Jax Diamond Member

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    Its probably because of the effect it would have on the jury. Even though they can be beaten (lie detectors not jurors :)) my impression is that it takes an absolute professional to do so.

    As a result, I would be likely to give more weight to a lie detector result than to other evidence.
     
  3. tweakmm

    tweakmm Lifer

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    Because they wouldn't be accurate evidence.
     
  4. astroview

    astroview Golden Member

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    it's hearsay too in some ways.
     
  5. Encryptic

    Encryptic Diamond Member

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    From what I understand, you can beat them, but it's not like you can do that by accident or something. Probably too much potential for tampering in that case, I suppose. Same thing with photographic evidence.
     
  6. Corporate Thug

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    it takes a lot to beat them doesnt it? its not like its something that you can learn or just pick up
     
  7. yowolabi

    yowolabi Diamond Member

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    Because they aren't 100 %accurate , but juries would treat them as if they were more reliable than they actually are. You can tell a juror that the test is only __% effective, but after they see you failed the test, start fitting yourself for an orange jumpsuit.
     
  8. LikeLinus

    LikeLinus Diamond Member

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    Also I?ve heard of results not being "100%" conclusive. Things like anxiety and racing heart also can throw the test. It's really hard to rely on something that can be 1. Beaten 2. Isn't always 100% reliable

     
  9. yukichigai

    yukichigai Diamond Member

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    As people have mentioned, if you're really nervous you can get a false positive. That and it can be beaten. Were these admissible in court you would see professional criminals getting off because they learned how to beat a polygraph while some poor innocent guy who's nervous as hell during the test gets 20 to life.
     
  10. DougK62

    DougK62 Diamond Member

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    From my experiences, they're highly inaccurate. Once I fooled it when I was lying and it said I was telling the truth, and several other times I was telling the truth and it said that I wasn't. IMO, they're nearly worthless.

     
  11. weezergirl

    weezergirl Diamond Member

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    At work we have to take lie detector tests and SO many people fail it just because they are so nervous. It's basically normal for you to fail it and have to retake the tests several times in fact. Kind of dumb huh?
     
  12. LikeLinus

    LikeLinus Diamond Member

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    Totally defeates the point of being a Lie Detector :D After you've taken it a few times...who knows what the truth is!
     
  13. Dudd

    Dudd Platinum Member

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    In the immortal words of George Costanza: "It's not a lie if you can make yourself believe that it's the truth.
     
  14. Armitage

    Armitage Banned

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    Google on polygraph ... even the official studies only find them to be about 90% accurate with the general population in contrived cases. Compare that to the far less black & white information you're typically considering in a court case, and the possibility of training, to avoid detection, and I'd say they're nearly worthless. IMHO, the only reason the government uses them for security clearances is intimidation and self-elimination purposes.
     
  15. dmw16

    dmw16 Diamond Member

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    They arent very accurate. If you are nervous (and you should be if you are being questioned for a serious crime whether you did it or not) they can give false readings. I have a friend who is currently applying to the NSA and is having trouble w/ his polygraph because he is getting nervous.
    -doug
     
  16. CrazyDe1

    CrazyDe1 Diamond Member

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    Well the thing is they tell if you're being deceptive or not. I think if I were to take one, questions that are BS I'd try to be deceptive. Like if someone asked me my name I'd say it was Chris Smith instead of Christopher Smith so in my mind I'd know I tricked the machine because it's really Christopher. But if it said I was lying I'd be like what? My name is Chris Smith. That, and I think even if I was telling the truth my mind is deviant and I'd always be thinking about the wording of the questions. I don't know how it tells if you're lying but I heard it has something to do with heartrates which some people can control. I mean, then the funny thing is if I was lying then I could go to them and be like look, your machine said I was lying on my name, it just doesn't work.

    I'm not sure, but I always think people think I'm lying when I'm questioned about things.
     
  17. Siddhartha

    Siddhartha Lifer

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  18. amnesiac

    amnesiac Lifer

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    No, the polygraphs are VERY VERY accurate.
    They measure what they're supposed to do and do it well.

    The problem is that the people ADMINISTERING the polygraphs are, after all, only human.
    Plus, there is no standard ruling body for polygraph education and administration, so while you have some very good PIs that spent time with police work, detective work, and completed intensive polygraph education courses and are certified by the national organization, you have others who took a fly-by-night class that do the same thing but with much less accurate results.

    That being said, you can have the same test shown to two different testers - one with 30+ years experience and one with 2 years.. chances are the 30+ veteran will have an accuracy rating of well above 95%.

    That is not, however, acceptable as far as courts go. They can't have uncertainty when distributing justice, and that is why polygraphs are not admissable.
     
  19. amnesiac

    amnesiac Lifer

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    LMAO just do yourself a favor and never get in that situation.

    It's much, MUCH harder to fool a polygraph than people would have you believe. Those articles you read in magazines about using a tack in your shoe and everything don't work too well especially when you find yourself in the actual situation.
     
  20. ScottyB

    ScottyB Diamond Member

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    Most of the time they say truthful people are lying because they are nervous and lot's of times they say guilty people are telling the truth.
     
  21. Wallydraigle

    Wallydraigle Banned

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    I think it would violate someone's fifth ammendment rights if they were made to take a polygraph before a court. Putting polygraphs in court rooms would also undermine our justice system, the core principle of which is that when all the evidence is presented, the truth will be known. Letting a machine determine our guilt would undermine all of our inalienable rights. Just seems like a bad idea to me.
     
  22. element

    element Diamond Member

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    It's not really easy to 'fool' a polygraph test. The problem is false positives and negatives are rampant. What a polygraph machine tests is your vital signs like heartrate, breathing pattern, sweat, etc. The problem here is that these are not accurate indicators of lying! So while the polygraph machine itself isn't inaccurate in what it does, the body is inaccurate in changing patterns when you lie or tell the truth. Sometimes even if you're telling the truth your vitals will jump from being nervous, and sometimes the vitals will not change much at all even if you're lying. Ever answer a question without giving it much thought? There is an instance where you might lie and show no signs of it.
     
  23. Armitage

    Armitage Banned

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    Here's a good read on the subject: The Polygraph and Lie Detection

    Check out Chapter 8 to cut to the chase...

    Polygraph Accuracy Almost a century of research in scientific psychology and physiology provides little basis for the expectation that a polygraph test could have extremely high accuracy.

    Theoretical Basis The theoretical rational for the polygraph is quite weak....

    Utility Polygrap examinations may have utility to the extent that they can elicit admissions and confessions, deter undesired activity, and instill public confidence. However, such utility is seperate from polygraph validity.


     
  24. IamElectro

    IamElectro Golden Member

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    Being nervous has nothing to do with it. You are a asked a series of 10 questions and only 3 are pertaining to the subject at hand. This is repeated 3 times for a total of 30 questions and the questions are asked in random order each time. You take a break in between each group of questions and they play a game like write a number on a piece of paper and the examiner will ask a if the numer is say 10 you answer yes or no. The reason for this is they know your nervous and the do this to get a baseline of vitals. The deception is based on the fight or flee concept meaning you can lie but your body can't in short when the question is asked that you may be lying about your heart may speed up for a second or you hold yor breath etc. all of which is monitored by the polygraph and is compared to the rest of the graph any varations in the chart where the important questions are asked may show disception.

    Yes poloygraphs are accurate and yes they can be beat. They can be used in court only to show discovery in the investgation process.

    Why do I know this because a pizza shop I worked at while in school a couple a years ago got robbed "inside job" everybody working that day got a oneway ticket to a poloygraph. It sucked and the dude got busted because he failed the test got scared and admitted to it even though he could have gotten away with it because thats all the cops had was the test and that is not enough for a conviction, but his admitance was.

    Just my 2 cents
     
  25. element

    element Diamond Member

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    If only everyone reacted the same to a polygraph test as the subject in your case, it would be a more useful test.