The question of the polygraph?

[stephen25000]

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

If the system is no good, then why are polygraphs used around the world ?

[Benice]

No system is perfect.

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

Dear me  - I'm not sure the innocent person who failed the test would have been too thrilled if that was the explanation given to him. 

''Oops sorry we thought you were a murderer  - but no system is perfect - OK?''

[Mr Gray]

No system is perfect.

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

that is called anectdotal evidence and has no value

[Alice Purjorick]

Polygraphs are like so many other things in life, including dogs.
Some folk swear by 'em others swear at 'em depending upon the point one is attempting to make.
Are the arguments on either side scientific or pseudo-scientific?
Tune in next week.

[stephen25000]

Dear me  - I'm not sure the innocent person who failed the test would have been too thrilled if that was the explanation given to him. 

''Oops sorry we thought you were a murderer  - but no system is perfect - OK?''

You do realize of course that will be used normally as part of an investigation, and not the only singular element of one ?

[Mr Gray]

If the system is no good, then why are polygraphs used around the world ?

spiritualist mediums are used all round the world.....
again...if you think polygraphs are reliable it is a good indication of your poor understanding of what is...and is not ....proper evidence. So in both the UK and Portugal Kate's testimony would be accepted in court as evidence...a polygraph would not...does that tell you anything

[stephen25000]

that is called anectdotal evidence and has no value

Read my previous answer.

[stephen25000]

spiritualist mediums are used all round the world.....
again...if you think polygraphs are reliable it is a good indication of your poor understanding of what is...and is not ....proper evidence. So in both the UK and Portugal Kate's testimony would be accepted in court as evidence...a polygraph would not...does that tell you anything

What scientific basis do spiritualists have ?

With the polygraph, there is a difference.

[Mr Gray]

Polygraphs are like so many other things in life, including dogs.
Some folk swear by 'em others swear at 'em depending upon the point one is attempting to make.
Are the arguments on either side scientific or pseudo-scientific?
Tune in next week.

but it's not our opinions that count..it's the court's.....which accept neither...that is a fact...which 100% supports my argument

[Mr Gray]

What scientific basis do spiritualists have ?

With the polygraph, there is a difference.

polygraphs claim scientific basis...they are still unreliable

[Mr Gray]

What scientific basis do spiritualists have ?

With the polygraph, there is a difference.

I'm sure you will find cases ..around the world....of police forces using psychics

[stephen25000]

but it's not our opinions that count..it's the court's.....which accept neither...that is a fact...which 100% supports my argument

Some states in America do accept their use dave, as long as both sides agree to their ususer ?

and are subject to the discretion of thge trial judge in the Federal Court.

[stephen25000]

I'm sure you will find cases ..around the world....of police forces using psychics

I am already aware of that.

Have you asked SY if they are ?

[Mr Gray]

Some states in America do accept their use dave, as long as both sides agree to their ususer ?

and are subject to the discretion of thge trial judge in the Federal Court.

so now it's some states...not all..at the discretion of the judge and if both sides agree...because they are unreliable

[stephen25000]

so now it's some states...not all..at the discretion of the judge and if both sides agree...because they are unreliable

So why do some use them ?

I never said everyone, I.e. court or police investigation used them.

I said they are used around the world.

and that is true.