Lie Detectors

@hue-man,

Should you force a criminal suspect to take a lie detector test? Sure, I think that should be part of a normal investigation. Maybe it will help, maybe it will not help. Should the results of the lie detector test be admissible in court? No, because the standard lie detector is certainly not a 100% accurate machine. People could be naturally anxious or nervous which could influence the results of the test.

But take this situation into account. Say Alan and Bob hate each other. Alan really hates Bob and Bob really hates Alan. Bob really hates Alan to the point where he, in his mind, plans to kill him. One day Alan is found dead, but it was by the hands of Charles, who in no way had anything to do with Bob. Bob, known to everyone as someone who really hated Alan and had the motive to kill him, is questioned. In a lie detector test, the officer could ask "would you wish any harm on Alan?" The detector for all intensive purposes could find Bob guilty regardless of his answer. The officer could also ask "would you kill Alan if you had the chance?" Bob, who actually had thought of killing Alan would be screwed here to. But thinking of committing a crime and actually committing it are completely different things, and this is recognized under the law. Now you bring a machine into the mix, which quite possibly measures the intentions of an individual's as well as the actions and you blend these two aspects together, is fundamentally wrong because the machine measures both intention and actual crime.

But interestingly enough, FMRI tests are being evaluated right now to be used as permissible evidence in the court right now, and from what I understand it is actually looking very good for the tests. But the tests are said to be 97% accurate. That is certainly a good number, but I do not agree that something like this should be admissible unless it is 100% accurate. It's like the death penalty? it the system is not 100% foolproof, the chances are that some who are sentenced to death that may in fact be innocent are possible.

1 Reply

@hue-man,

I thought that a lie detector measures the rate of your heatbeat so when you're asked a question and if you lie you get nervous because you're lying and so your heart rate beats faster but i always thought if it were me i'd be nervous wether i was guilty or not and that's what concerns me about lie detectors, they dont actually detect lies they detect heart rate, i'd find a sereously good lawyer because on that basis i dont trust them, maybe im wrong? I also heard it has been known for crimianls to suss this out and learn to control thier heartbeat and slow it down when asked about crimes they did, so unless research proves otherwise they're a are not proven to be totally reliable. I think at best they're a bit of fun on the Jerry Springer Show to test an unfaithful partner but shouldnt be used as hard evidence in a court of law, i dont think they confirm anything and i think hard evidence is what is best/needed to convict a criminal.

1 Reply

@Caroline,

No. The lie detector machines are not 100% accurate and easy to fake. By lying, ironically enough.

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@hue-man,

What I dont understand is that in some cases lie detectors are used as evidence against or for someone in court.

1 Reply

@Caroline,

Caroline,

I completely agree with the fact that anxiety can have a factor in a polygraph test and may in fact influence the results of the test. But polygraph machines do in a sense detect lies, it's the method in which they record the body's response to the questions (and the "lie") that is the problem. In the typical polygraph test, looks not only at heart rate but blood pressure, respiratory rate, and electro-dermal activity (measured through the fingers). When the investigator asks you questions, they measure the fluctuations in the normal rates of the previously mentioned readings. But to do that, the investigator has to ask a series of control questions. These questions range from "what is your name" to "are you in this room?" I always thought it would be rather hilarious if an die-hard epistemologist or an existentialist answered these questions? would the answers be correct even though they superficially are? but not really? Could they then be used as control questions? But that brings up a good point, which is that control questions are almost never 100% accurate. So that is essentially evidence saying that a detector is faulty right there. And also because a criminal can essentially lie out a lie detector makes the whole system faulty as well.

Even on Jerry Springer, they shouldn't use those machines. I am still very confused as to whether or not what's on that show is real, but assuming it was, polygraph machines require a certain degree of discipline. The people that are put on those machines are?well? they are not the top of their class (both academically or genetically), so I would question their capacity to take the test and give a legitimate answer.

I mention the FMRI because it relies on the measurement of blood flow to specific parts of the brain. The essential gist of it is that neurons in the brain require more oxygen when activated and thus need more blood and hence increased blood flow. Those active areas then determine whether or not you are lying. But even this is not 100% accurate. And this is the only type that is even remotely close to being used as a standalone piece of evidence in court.

That you don't trust lawyers, I completely understand. They are there for you and they are there for the other guy as well. It's like the ancient Romans and actors. Any public gathering prohibited slaves, freedmen, and actors. But I would trust actors far less than lawyers. They in some instance represent people who are very bad people who really need to go to jail. But put yourself in that relative position and I think you would appreciate that aspect of a lawyers profession.

1 Reply

@hue-man,

Sorry im meant i'd find a seriously good lawyer as i dont trust them,ie, lie detectors, sorry i wasnt making myself clear although some lawyers cannot be trusted i actually had a really good one. I agree, i dont think they should use lie detectors on the jerry springer show, it all seems just a bit too ridiculas all for the sake of enertainment, most people who gone it want to be on tv and are quite happy if this means airing their dirty laundry to all and sundry, and the fights-if you notice the bouncers do take awhile to intervene because thats why alot of people tune in and if i've gone off topic that's only because im responding to ViciderSpoon's query.

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@VideCorSpoon,

VideCorSpoon wrote:

But take this situation into account. Say Alan and Bob hate each other. Alan really hates Bob and Bob really hates Alan. Bob really hates Alan to the point where he, in his mind, plans to kill him. One day Alan is found dead, but it was by the hands of Charles, who in no way had anything to do with Bob. Bob, known to everyone as someone who really hated Alan and had the motive to kill him, is questioned. In a lie detector test, the officer could ask "would you wish any harm on Alan?" The detector for all intensive purposes could find Bob guilty regardless of his answer. The officer could also ask "would you kill Alan if you had the chance?" Bob, who actually had thought of killing Alan would be screwed here to. But thinking of committing a crime and actually committing it are completely different things, and this is recognized under the law. Now you bring a machine into the mix, which quite possibly measures the intentions of an individual's as well as the actions and you blend these two aspects together, is fundamentally wrong because the machine measures both intention and actual crime.

This is without a doubt the best argument I've come across against the use of lie detector tests in criminal cases. It seems to me the methods used by the lie detector have no means of separating intention and action. And the questions can be asked in manipulative ways, so as to find someone guilty through clever semantics.

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@VideCorSpoon,

VideCorSpoon wrote:

Caroline,

Even on Jerry Springer, they shouldn't use those machines. I am still very confused as to whether or not what's on that show is real, but assuming it was, polygraph machines require a certain degree of discipline. The people that are put on those machines are?well? they are not the top of their class (both academically or genetically), so I would question their capacity to take the test and give a legitimate answer.

How do mean? I thought it didn't matter who you were, that the test is generic?

1 Reply

@Caroline,

Caroline wrote:

How do mean? I thought it didn't matter who you were, that the test is generic?

That a polygraph is generic? No, but I don't know if that is the right word to use though. As in the case of Alan and Bob (post #2), a polygraph is useful only so far as accuracy is concerned. The machine could pick up internal biases that have nothing to do with the issue the person is being questioned about, rather the capacity of the person. The fact of being human and having the ability to be hooked up the machine is immaterial compared to the mental capacity to answer those questions correctly.

Case in point. Take the "generic" Jerry Springer guest (assuming they are as mentally hilarious as they are portrayed). Supposing the generic guest has some serious social problems, mental issues, whatever, and you hook that person up to a polygraph machine, you would definitely not have a reliable result. They are not applicable to the standards of the test. This is where the comment on "polygraph machines require a certain degree of discipline" comes in. There are a few reasons for this assumption.

One assumption is that (in my mind) to have a reliable polygraph readout presupposes a "rational person." This is an issue that is highly debate within the context of the law. As in the case of pleas of insanity, a person who murders another (assuming the existing precedence) and is mentally challenged is not judged under the same rubric as a "rational person." In a sense, the mentally challenged person may not in some way understand that what they did was wrong. Theory and precedence determines that because they do not know that what they did was wrong, they cannot be held to the same standard as a rational person.

So with that being said, do all persons hooked up to a polygraph infer some manner of generic quality? I would say yes in so far as the physical component is concerned, that they have ears to hear the question, a mouth to provide the response, and vitals to monitor in order to gauge the responses. Of course responses could come via different ways, but that is just to deliver the point of responses etc. But on the whole, I would say no because what is truly meaningful in a polygraph is the mental component and assuming the clich? Springer guest, the prerequisites for a rational person are not there.

1 Reply

@VideCorSpoon,

I thought you all might be interested to know that there is a new lie-detection technology being developed:

fMRI (functional Magnetic Resonance Imaging) scans the brain chemistry for enzyme concentrations or significant blood increase to specific parts of the brain that denote lying.

Here's two companies that are developing the technology:

No Lie MRI - Home Page

and

Cephos Corp home page. We believe truth is a valuable commodity and have proven services to help you find it.

Liars of the world - watch out!

-ITL-

1 Reply

@IntoTheLight,

IntoTheLight;107727 wrote:

I thought you all might be interested to know that there is a new lie-detection technology being developed:

fMRI (functional Magnetic Resonance Imaging) scans the brain chemistry for enzyme concentrations or significant blood increase to specific parts of the brain that denote lying.

Here's two companies that are developing the technology:

No Lie MRI - Home Page

and

Cephos Corp home page. We believe truth is a valuable commodity and have proven services to help you find it.

Liars of the world - watch out!

-ITL-

There was a brief mentioning of it in a previous post.

VideCorSpoon;56576 wrote:

But interestingly enough, FMRI tests are being evaluated right now to be used as permissible evidence in the court right now, and from what I understand it is actually looking very good for the tests. But the tests are said to be 97% accurate. That is certainly a good number, but I do not agree that something like this should be admissible unless it is 100% accurate. It's like the death penalty? it the system is not 100% foolproof, the chances are that some who are sentenced to death that may in fact be innocent are possible.

Unfortunately, it is not entirely 100% accurate.

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@hue-man,

I think there are good Fifth Amendment reasons for not requiring criminal defendants to take polygraph exams -- even if the polygraph results themselves are not introduced as evidence at trial.

And it's not clear to me what people have in mind in speaking of "forcing" defendants to undergo polygraph exams. Is this supposed to mean physical coercion? Is it supposed to mean imposing legal sanctions on a person who refuses?

In any case, I don't think that the case against using lie detector tests in criminal trials necessarily turns on the accuracy of lie detection methods. It has a great deal to do with the way that lie detectors might be viewed by juries. In particular, there is a danger that juries will allow polygraphs and other forms of lie detection to usurp their function as the ultimate triers of fact in criminal cases. In this sense, even the most accurate lie detection machine raises cause for concern, since the more reliable the lie detector is thought to be, the more likely a jury will be to defer to its findings. Which of course would raise serious problems for any system of criminal justice based on trial by jury.

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@hue-man,

OF COURSE!
Though, we should not rely on them.
No technology can be trusted 100%
We should use them to help weigh on the final decision.
Though, difficult, it's possible to cheat them through changing your heart rate.
On the other hand, if they didn't work why would we still be using them?

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@hue-man,

Yes, since the psychological aspects of subjecting someone to a lie detector test reveal more than the results of the test itself.

If you tell a suspect/witness that a lie detector test will be taken, reactions to the thought of taking a lie detector test may prove more useful than the test itself. Lie detectors simply measure heartbeat as mentioned earlier, but there could be some other use.

1 Reply

@Leonard,

Leonard;125324 wrote:

Yes, since the psychological aspects of subjecting someone to a lie detector test reveal more than the results of the test itself.

If you tell a suspect/witness that a lie detector test will be taken, reactions to the thought of taking a lie detector test may prove more useful than the test itself. Lie detectors simply measure heartbeat as mentioned earlier, but there could be some other use.

Telling someone that they will be under a certain test will alter the results. The Hawthorne Affect.

1 Reply

@Ccalebb,

While certainly usefull for an investigation, I agree lie detector tests arent perfect enough to be considered proof, I think they should at most be considered something like a witness, that is, an uncertain proof.

I remember watching a myth busters episode where they were trying to fool lie detectors. They tested both the current technology and a new one under development. If I remember well, they (3 of then) failed to fool the current technology, but one of the managed to fool the new technology by mantaining his brain in constant activity during the test.

I also remember watching a program about a new lie-detector like technology that detects whenever the brain reconizes what is being show or not. The idea is this: They show several images and texts to the person, both related and unrelated to the crime, some of witch are undisclosed information that only the criminal or someone with some relation to the crime could know, then analyze the results. This sounds more reliable to me, but I think it probally can also be faked.

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@hue-man,

hue-man;56572 wrote:

Do you guys believe that we should force a suspect to take a lie detector test? Please explain why you do or don't?

Some are so unemotional that they can cheat a lie detector, it's not a fool proof way of catching criminals, as it will also mistakenly take those who are of frail mind.

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@hue-man,

All I know is the day I'm doing a lie detector for something that will effect the rest of my life I'll be nervous regardless.

If you were a suspect for murder wouldn't you be?

Contra to being unemotional the mind can create many states on it's own; especially if the person has a sensitive/dysfunctional temperament to begin with.

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