[ARCHIVED THREAD] - Polygraphs: How accurate? (Page 1 of 2)
Posted: 1/20/2007 12:51:20 PM EDT
| Polygraphs: How accurate are they? How well can they actually detect deceptive changes? |
If you could provide any information that they are any better than flipping a coin in detecting falsehoods I am sure everyone here would like to see it. The last time I checked there wasn't any such evidence -- which is why they aren't allowed as evidence in court. Personally, I will take witch doctors over lie detectors. They have the same level of accuracy in detecting lies, but the witch doctor is more entertaining. |
In other words, the odds are about 2-1 that it is wrong? I would hate to use that "compass" for navigation. Witch doctors get better results with "oooga-booga". |
I fail to see the connection between your reply and his statement. They ARE very useful in interrogations, if only because people out there believe they can detect lies. Many people have cracked and admitted to things when hooked up to them. They also magnify physiological reponses that are harder to detect just by looking at someone - and can provide interesting insight. |
Unfortunately, I have seen very few gifted operators. It can be very subjective. Yes the little needles hopped around on the paper. BUT WHY. It required WELL worded questions, and other indicators to understand why the response was indicated on the graphs. If the exact questions are not reviewed before being hooked up to the machine. Don't take a polygraph or depend on the results of a test. Being surprised by a question or being surprised by the question being changed can cause the readings to show a reaction to the question. I have taken two. Both pre-employment. I was asked to take a third after "money was missing" after searching a house for a fugitive. My response. Come back and ask me again after the complainant takes and PASSES a polygraph. That never happened. If you want to talk voodoo, get me in a conversation about the Voice Stress machines. I have heard of them being used off of tape recordings, monitored telephone calls, and in person like a polygraph. With the person each time declaring the subject was lying in the conversation. There is a reason the results of these "lie detectors" are not admissible in court. Too subjective, and the skill of the operator factors in heavily as to the actual results of the test.
Yes, but only to the point people will start telling the truth or out right confess to telling a lie before or after the test, because of fear of the machine or what they think it is capable of. I have heard of paper punches being used as a "lie detector" in the old days when interviewing juveniles who had no idea what a polygraph looks like. Yep... they started telling the truth. The accuracy of that paper punch or the paper punch operator did not have a thing to do with the results! |
| I wonder how the polygraph compares to this as an interrigation tool? |
In other words, they are only useful because they scare the ignorant. I prefer the witch doctor for that. Nice hypothesis. Now do you have any information that shows that your hypothesis is correct? You know, actual research that defines when and how they are accurate? |
The voice stress machine thing drives me batty! Why are so many people in the Law Enforcement and Intel fields so willing to believe voodoo science - and spend tax dollars on it? Of course, those stupid iodine "counterfeit detector pens" are all over the world now - people are just stupid, I guess. |
Your lack of reading comprehension does not support you claims of the benign nature of marijuana. |
Slight correction -- they are entirely subjective. There isn't anything that clearly says "lie" or "truth". It is all interpreted from a bunch of squiggly lines. They are no better than a Rohrschach test. A few years back a news show did a segment on lie detectors. They got the best "experts" in the field at the time. The lie detectors went 0 for 4 and, in every case, the person administering the test was absolutely sure they had found the guilty party. |
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An interesting "lie detector" That i know has been used in the past on a few of the more "unsophisticated" (read stupid) suspects is a copy machine. yes, a copy machine. You see, you take the subject, have him place his hand on the side of it, then ask him a question that you know he will lie about. Once he responds, hit the button and the machine (pre-loaded with paper with the word "lie" printed on it) should spit out it's response. at this point the investigator picks up the paper and says something to the effect of "you lying motherfucker..." I know of a few local cases solved by this technique, although it isn't as effective today since copy machines are more common. But back in the day it supposedly worked pretty well. |
Nationwide said it best in his post. The only thing they reliably measure is physiological responses. Nobody you seem eager to argue with here is saying otherwise. I have personally seen a thief thrown in jail thanks to a polygraph. They strapped him to it and he sung like a canary when the reader called his bluff and told him the machine said he was lying. He even went on to tell CID where they could find some of the stolen computers. Again: Useful interrogation tool - Yes. Lie Detector - No. Since the beginning of time, skilled observers have been able to watch people for signs of stress, responses to question, etc. to help them assess a situation. Some used those skills to fight crime, others to hustle people out of money (that "talking to the dead" guy, for example). The polygraph simply allows more to be observed. There is no science linking those observed physiological responses to lies. I never said there was. NOBODY in this thread has said there was. So WHY are you asking us to provide the science that shows this? |
OK, we agree on that. There is no evidence that they are accurate and nobody will come up with any. Then we have your assertion that they are useful because stupid people (who don't know that there is no evidence that they work) get scared and 'fess up. As I said, that is an interesting idea. However, I don't see anything to support that idea other than your own opinion. If your opinion is correct then somewhere there should be something besides your opinion (research) that shows that it is useful in those instances. As near as I can tell, there is no real research to support your idea, either. ETA: The question at the top of the thread asks whether they are "accurate". The answer to that would be "no". |
I have to take polygraph test to maintain my employment. A polygraph basically measures your response to deceptive answers. They give you a question or two to lie to, these are control questions. In my last test they even had me recall something and specifically think about it when I lied. They then have a series of questions that you answer truthfully and pertain to what you are taking the test for. In my case they involved National Security and Subversive activities aginst the U.S. All questions are throughly discussed before the test begins. The lie questions give them a baseline to measure your truthful responses against. On my last polygraph they had a pad to detect if you were clenching your ass. You have to remain perfectly still and breath normal or it can throw the whole test off. I screwed up and answered truthfully to a question I should have lied to. It tanked the whole test and I had to sit through a different test that you did not lie to any questions. What was screwed up about the control question in the second exam is they were not questions you could answer truthfully. They basically forced you to lie to get their baseline. I passed the second test with flying colors. |
My opinion? Are you suggesting that the FACT that a man was caught and thrown in jail thanks to a polygraph is just an "opinion." |
I am suggesting that any generalization about whether they are "useful" is an opinion, unsupported by any research. People see all kinds of strange things. Just because you saw one stupid person who was dumb enough to believe it doesn't mean that there is any evidence that the technique is generally "useful." In general, it isn't "useful" to waste your time with any pseudo-science, just because pseudo-science wastes your time overall and leads to bad decisions. If a witch doctor scared somebody into confessing would you recommend the use of witch doctors as a "useful" tool? |
Phone Books work too. If they happen to fall down the figure 4 leg lock works good and it does not look like your really doing anything. |
Then my statement that they only work on the ignorant is correct. Of course, never mind the fact that pseudo-science of any kind will give you just as many wrong answers as right one. Of course, the other question was whether you had anything but your own opinion (research, for example) that would show that even what you mentioned occurs with enough frequency to call it "useful." I take it there isn't any evidence of that, either. |
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ive taken the poly and the cvsa and they both are absolute crap, its just a big mind fuck. "uh oh the box says your lying, you better confess or your in big trouble" failed the poly passed the cvsa, same questions the grilled me on totally different topics. but I still passed the CVSA whatever the hell that means... 
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you're being incredibly argumentative for no reason. They are accurate (at measuring physical response) They are useful for the insight they give you into someone's state when responding to a question. You can use that info as an interrogation tool to break subjects down. Go to all of the anti-polygraph sites out there and they will all admit they are useful as an interrogation tool and the first rule is if you are lying, stick to your story. The reason there isn't a study out there is only a fucking moron would need a study to prove how it could be useful in an interrogation. I'm not even a cop and I've used the results of one to find out who was stealing computers from my company. Ask a cop, ask the experts, read the literature, every one points to it as an outstanding tool simply because people think it works. Its simply another mind game interrogators use (like claiming they have a confession from one of your friends saying you were both involved, claiming they have DNA evidence, etc..). Its all designed to force a confession. Once they have that, they don't need the evidence. |
Which, as noted, may have nothing to do with whether they are telling the truth.
Not if the original assumptions about why the needles are jumping is wrong.
Uuuuuh, yeah, the only reason there is no research to prove that is because anyone would be a fucking moron to ask for it. Just offhand, it seems to me that -- if there was such research -- it would be incredibly useful to the people who make polygraph devices. Advertising, and all that, you know.
Yeah, a news show did an experiment on that some time back and the best examiners in the business went 0 for 4. Of course, there is nothing to say that you didn't get lucky -- the odds are about even.
I have asked the experts thanks. The best answer I can get is that you would be a moron to ask for proof of such a thing. Nobody seems to come back with any actual research to prove it.
In other words, as I said before, it only works on the ignorant. If you get anyone with a halfway reasonable education on the subject, it would be useless even for that. |
We have come to a point of agreement. |
I take it you are "required" to take them -- therefore, both the ignorant and the educated would take them, I would presume. I would think that with that particular crowd, they would be somewhat better educated than most, so the whole routine would tend to be a bigger waste of time than most polygraphs. Except in the case where the polygraph examiner gets it wrong and they wind up falsely accusing someone of something. In that case, you would have to say that the people who give the polygraphs are just plain stupid. |
I don't see where we ever disagreed. You just have a habit of creating red herrings or straw men to get all irate about. |
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I had a friend with me one night while I was driving around town and we were drinking. I was 17 at the time. I was about to stop at the sign when a male black was walking across the street and he approched my window and asked if we wanted some 'caine. I punched him in the mouth and drove off. I made a right turn and then another right turn at the next street. It so happened that the guy ran to the next street and fired one round from a pistol which struck my buddy in the right ear. I drove to the hospital and was greeted by the police and I gave them a statement. I was asked where my truck was and gave them the keys. I was told to stay put as the homicide detectives were on the way and would interview me . I was allowed to drive to the station in my truck and parked it in the impound. Those guys grilled my ass all night long. They accused me of shooting him. They had a crime scene tech do a paraffin test which was negative. I finally had enough and VOLUNTEERED to take a poly exam. The next day I was driven to their examiner and failed miserably. I told the truth with every question asked. The only thing that kept my ass out of jail and being charged was the paraffin test. It didn't matter. They twisted my balls for two weeks. My buddy came out of his coma and told the Detectives exactly what I had origially told them to begin with. The Police found out who shot him but he lawyered up and no charges were filed. A few years later that same guy shot someone else at a party with a 357. He is now doing life w/o parole. I will never take another polygraph examination again. NEVER. |