The question of the polygraph?

[stephen25000]

it isn't my opinion..it's a scientific fact

Cite.

Now if lie detector tests are unreliable, why are they used around the world ?

Echoes of the use of dogs here.

[Mr Gray]

Cite.

Now if lie detector tests are unreliable, why are they used around the world ?

Echoes of the use of dogs here.

if you think lie detectors are reliable you are seriously deluded..

[Benice]

Cite.

Now if lie detector tests are unreliable, why are they used around the world ?

Echoes of the use of dogs here.

Please provide the scientific  proof that polygraph tests are 100% accurate.

[Mr Gray]

The county prosecutors offered Buzz a deal: they would drop all charges if he agreed to take a polygraph – a lie detector test – to prove his innocence. Convinced the whole episode was one big mistake, Buzz readily agreed. He took two tests but both suggested he was lying about his innocence. This, along with circumstantial evidence, sealed his 1979 conviction and he spent two-and-a-half years in prison for a murder he didn't commit.

During his time in prison, Buzz studied the polygraph. He sent his results to a number of experts but received wildly different interpretations. Determined to show the test was fallible, he developed a training exercise to help people fool the lie detector and after just 15 minutes of instruction, 23 out of 27 inmates beat the polygraph. Buzz was eventually exonerated, helped by the testimony of the real killer's mother, and his case has become one of the most notorious episodes in the history of the technology.

[stephen25000]

if you think lie detectors are reliable you are seriously deluded..

I asked you for a cite.

[stephen25000]

Please provide the scientific  proof that polygraph tests are 100% accurate.

Who said they were.

[Mr Gray]

I asked you for a cite.

it's like asking me for a cite that father Christmas isn't real.......

[stephen25000]

it's like asking me for a cite that father Christmas isn't real.......

Dear oh dear.

So why are they used around the world?

[Benice]

Who said they were.

You said this:

''Now if lie detector tests are unreliable, why are they used around the world ?''


In view of your reply I take it you have no scientific evidence to prove that polygraph tests are not unreliable.

However, that's not surprising - as there isn't any.

[stephen25000]

You said this:

''Now if lie detector tests are unreliable, why are they used around the world ?''


In view of your reply I take it you have no scientific evidence to prove that polygraph tests are not unreliable.

However, that's not surprising - as there isn't any.

You really must try and comprehend.

I have never said they were 100%

Why do you fear them so much, in connection with the mccanns ?

Now that is a very pertienent question.

[Lace]

and of course, if the mccanns had both done the test and failed, guess what, it could show they had been lying.

 

Stephen have you ever watched any 'True Crime'   programmes which reveal true crimes committed in America and how they go about catching the people responsible?

If you do,   you would know that many times a person they have as a suspect has failed the test,   yet have been proven to be innocent.

One man in particular was smiling when asked if he had killed someone [they thought,   this guy is the one]  turned out he failed the test,  they thought they had their man,  but he wasn't he was innocent.

[G-Unit]

If it was so easy to spot a liar - there would be no such thing as a '[moderated].'

Some people believe everything they're told and can't spot liars. Others can. [moderated]s pick their victims for a reason. I watched a programme where several silly older women were complaining because they'd been tricked out of money by young foreign men. They had convinced themselves that a young attractive man had fallen in love with them. People who get tricked usually have a weakness such as loneliness or greed. Con men home in on these weaknesses.

[Brietta]

I've found nothing which states categorically that polygraph tests are infallible and in my opinion the demand for the Drs McCann to take one is merely another entertainment exercise for those with little else in their lives, to damn them if they do and to damn them if they don't.

Predictable and tiresome


AMERICAN PSYCHOLOGICAL ASSOCIATION

The Truth About Lie Detectors (aka Polygraph Tests)

Most psychologists agree that there is little evidence that polygraph tests can accurately detect lies.

**snip
The accuracy (i.e., validity) of polygraph testing has long been controversial.

An underlying problem is theoretical: There is no evidence that any pattern of physiological reactions is unique to deception.

An honest person may be nervous when answering truthfully and a dishonest person may be non-anxious.

Also, there are few good studies that validate the ability of polygraph procedures to detect deception.
As Dr. Saxe and Israeli psychologist Gershon Ben-Shahar (1999) note, "it may, in fact, be impossible to conduct a proper validity study." In real-world situations, it's very difficult to know what the truth is.

A particular problem is that polygraph research has not separated placebo-like effects (the subject's belief in the efficacy of the procedure) from the actual relationship between deception and their physiological responses.

One reason that polygraph tests may appear to be accurate is that subjects who believe that the test works and that they can be detected may confess or will be very anxious when questioned.

If this view is correct, the lie detector might be better called a fear detector.


Some confusion about polygraph test accuracy arises because they are used for different purposes, and for each context somewhat different theory and research is applicable.

Thus, for example, virtually no research assesses the type of test and procedure used to screen individuals for jobs and security clearances.

Most research has focused on specific incident testing. The cumulative research evidence suggests that CQTs detect deception better than chance, but with significant error rates, both of misclassifying innocent subjects (false positives) and failing to detect guilty individuals (false negatives).
http://www.apa.org/research/action/polygraph.aspx

[Benice]

You really must try and comprehend.

I have never said they were 100%

Why do you fear them so much, in connection with the mccanns ?

Now that is a very pertienent question.

So do you agree  that if they are not 100% reliable then it can never be claimed that 100% of the test results are accurate?   In that case how could a test have ''exposed the McCanns for what they are'' - which is what you also claim?     You can't have it both ways.

[stephen25000]

Stephen have you ever watched any 'True Crime'   programmes which reveal true crimes committed in America and how they go about catching the people responsible?

If you do,   you would know that many times a person they have as a suspect has failed the test,   yet have been proven to be innocent.

One man in particular was smiling when asked if he had killed someone [they thought,   this guy is the one]  turned out he failed the test,  they thought they had their man,  but he wasn't he was innocent.

No system is perfect.

How about giving examples of cases where it has proved more than useful.