Lie Detectors

[psi20]

If you were a murderer named John who was hooked up to a lie detector while being interrogated by police officers who asked you if you were a murderer and you answered no, would the lie detector pick up you told a lie no matter what? If five seconds later the next question was what is your name and you answered John, would the lie detector indicate you told a lie?

 

I'm assuming that this lie detector detects lies by the body's response.

 

If the person hallucinates often, can that person make the truth a lie and the lie the truth?

[Lance]

I think lie detectors are really a scam. I’m surprised it’s aloud as evidence in any states (isn’t it aloud in a few states?) If I was accused of a crime I would refuse to take it even if I was not guilty. They are extremely inaccurate and not only that people could judge the results differently. I’m assuming you’re talking about a polygraph?

[galaxygirl]

You're right psi20, lie detectors are used to see a persons physiological reactions, and don't detect lies. They do this by monitoring a subjects respiratory rate, blood pressure, and finger sweat. Those physiological changes can be caused by things other than lying, and some people can have no reaction at all. For example, someone that knows meditative breathing will be able to prevent these changes, whereas someone who is really nervous could experience reactions even when they're not lying.

[psi20]

Is there any lie detector that really works? Or can all of them be skewed and twisted so that each side of the case interprets the data differently?

[galaxygirl]

As far as I know there is no lie detector that works 100%, but there are some new ways of figuring out a suspect's involvement in a case. Brain fingerprinting worked 100% on a test with FBI agents, but I'm not sure how it would work with someone who has amnesia.

[zpoot]

that's so weird, i saw the end of a movie w/ someone having to take a polygraph and i was thinking that exact same thing. I don't think they're a very good way to tell if someone is lying or not. You might as well just interrogate them w/o a polygraph and, if you're observant, you could get the same information...

[Cap'n Refsmmat]

The thing is, lie detector operators don't say "Did you murder him?" They first ask simple questions to see what the person does when they lie ("Have you ever stolen?" is a good one because practically nobody hasn't) and then they ask questions like "Do you know this person?"

But the thing is, some people may not believe they broke the law because they think the murder was justified. Or, alternately, they may not remember the whole thing because they were on drugs. The only reliable lie detector in my opinion is the brain scan. Of course, that's way more expensive.

[[Tycho?]]

How does a brain scan allow for lie detection, I've never heard of this.

 

Polygraphs do work, they are not a scam. They just dont always work. You can train youself in various ways to cheat a polygraph. Falsy accusing someone is trickier. They always start with questions such as "what is your name" "what are your parents names" and stuff like that. Basically they start with very easy questions, so they know what sort of readings you give when you tell the truth. When you ask something that makes a person nervous, you get higher readings. When the person lies, you get extremely high readings. The question is, where is the line between nervousness and lying? This is why lie detectors are opperated by humans, so they can judge the responses.

[Cap'n Refsmmat]

The brain scan thingy apparently can tell with much greater accuracy when they are attempting to be deceptive. There's a section of the brain that "lights up" when they're lying.

[LucidDreamer]

Prediction: It doesn't work nearly as well as they claim it does.

 

The law enforcement groups and lie detector operators have been claiming that lie detectors are accurate for years because its in their best interest to claim so. I don't know if the brain fingerprinting is any more accurate but I will bet you that it doesn't work as well as they claim it does.

 

The research administered by the FBI, the police, and the inventors of the technology always seem to give better results than the tests done by independent investigators who are not somehow invested in the technology. But I guess we will see how this technology pans out.

[muad'dib]

In reply number two Lance seemed questionable over whether or not polygraph results are allowed as evidence in court in some states. I don't believe they are allowed in court in any state because they aren't perfect and can give false positives; they are accurate about 98 to 99% of the time.

[LucidDreamer]

they are accurate about 98 to 99% of the time.

They are not anywhere near that accurate.

[muad'dib]

I just checked and I found that the accuracy does depend on who performed the study (as is the case with most studies in which one group has a vested interest in the outcome) as someone stated earlier, and can vary from 50% to 87%. So I was obviously wrong with the last post I made. Thanks for the correction LucidDreamer; next time I'll be sure to check more thouroughly when I use any statistics.

 

I did find that the Supreme Court will not allow polygraph tests in court because of the unreliability, and that most polygraph examiners will say that polygraph tests do not detect lies, they measure physiological functions only, it was the media and public that first called them lie detectors.

 

Check out http://www.howstuffworks.com that's where I got any information in this post, as to its reliability....who knows

[Guest Cyberian]

According to the following website, it is not difficult to pass a polygraph, even if one is lying:

 

http://antipolygraph.org

[Guest Cyberian]

According to the following website, it is not difficult to pass a polygraph, even if one is lying:

 

http://antipolygraph.org

[TseTseFly]

I think lie detectors are a way to cover up the weak observation skills of the interviewer. We need to read people better. Communication is key.

 

Just because the interviewer is filing divorce because he can't read his wife's emotional problems doesn't mean he can't do his job. I think it's plain enough to be able to just judge the characteristics of the inmate when he lies and says the plain truth. Plus the old saying goes... Not quoting but meaning, once someone has committed a crime they are liable to commit another one.

[atinymonkey]

I'd love for you to try that with me, Mr 'I can smell when they lie'.

[TseTseFly]

Well its only natural human instinc to be able to read each other. Lying is just something that came with the Bible or human language, either one.

[atinymonkey]

Man is inherently self absorbed, and so is naturally inclined to lie.

 

 

Language and religion are not at fault, it' s human nature.

[Artorius]

liar

[dagoflores]

Are all a bunch of liars, or just afraid...?

[smommer]

As far as I know there is no lie detector that works 100%, but there are some new ways of figuring out a suspect's involvement in a case. Brain fingerprinting worked 100% on a test with FBI agents, but I'm not sure how it would work with someone who has amnesia.

 

Do you know the sample size of this galaxygirl? i remain a sceptic about all kinds of "lie detectors" and really dont buy the idea we can decide whether someone is telling the truth or not depending on the amount we sweat or our cutaneous reactions. Im also not really familiar with what "brain finger printing" is.

[smommer]

Man is inherently self absorbed' date=' and so is naturally inclined to lie.

 

 

Language and religion are not at fault, it' s human nature.[/quote']

 

i agree

 

the sooner we can all agree we are all alone and get the **** on with it the ****ing better

[Mayflower]

']

Polygraphs do work' date=' they are not a scam. They just dont always work. You can train youself in various ways to cheat a polygraph. Falsy accusing someone is trickier. They always start with questions such as "what is your name" "what are your parents names" and stuff like that. Basically they start with very easy questions, so they know what sort of readings you give when you tell the truth. When you ask something that makes a person nervous, you get higher readings. When the person lies, you get extremely high readings. The question is, where is the line between nervousness and lying? This is why lie detectors are opperated by humans, so they can judge the responses.[/quote']

 

So, how do they know exactly how my body should respond to each question?

I could easily be more nervous over one question than another in a way that wouldn't relate to how much truth I'm telling and what the consequences are.

[Douglas]

I've taken numerous polygraphs (not crime related) and passed them all. However, I don't trust them. My 1st polygraph, I went through all the questions, only to be chewed out by the guy administering the test, because I had my leg crossed and I was very slightly moving my foot. I decided then that polygraphs were not reliable.

 

I was told by NSA people that a person can be trained to pass a polygraph.

 

BTW, all questions that I answerd were yes or no questions