Social Question

DarkScribe's avatar

Who still believes that lie detectors can't be beaten?

Asked by DarkScribe (15405 points ) March 24th, 2010

With regard to recent discussion about how easy/difficult it is to beat a lie detector, this article is pretty illustrative of just how unreliable they are. (A man who committed a horrific murder when questioned by Police beat one easily. )

See: http://tinyurl.com/ydzr96h

I wonder how different things might have been if Police had not relied on a lie detector to eliminate suspects. Few agencies will do so nowadays.

Observing members: 0 Composing members: 0

12 Answers

ucme's avatar

Jerry Springer?

meagan's avatar

@ucme Maury ;P*

Seek's avatar

A lie detector only picks up changes in perspiration and heart rate. To have those changes, someone has to fear being caught, or feel bad about lying.

It doesn’t work with psychopaths. Anyone willing to set 5 kids on fire for stealing a couple of joints is obviously a psychopath.

jaytkay's avatar

I had to take a polygraph for a job 20 years ago. I thought it was really interesting, and asked the examiner a lot of questions.

He said it didn’t work really well as a physical detector. But it was amazing the stuff people would tell him once they were hooked up to the machine.

zophu's avatar

I think there are some more advanced ones that read things like eye movements and stuff, but yeah, if you control your body you beat the lie detector.

sidenote: let’s stop burning people alive, k?

DarkScribe's avatar

@Seek_Kolinahr A lie detector only picks up changes in perspiration and heart rate

No, they work with a lot more than that. They can use skin resistivity, blood pressure, oxygen gas levels, minute changes in temperature, some even include voice stress algorithms. There are many different kinds, but if someone does not react then they can beat them (and they need not be a psychopath – they just need to not be afraid of the detector and examiner) or, as I have stated before, to have taken a large dose of Valium or similar. Most technicians who work with them regularly can beat them quite easily.

robmandu's avatar

Since 1998, the U.S. Supreme Court has ruled polygraphs to be unreliable for evidence, specifically stating that “There is simply no consensus that polygraph evidence is reliable” and “Unlike other expert witnesses who testify about factual matters outside the jurors’ knowledge, such as the analysis of fingerprints, ballistics, or DNA found at a crime scene, a polygraph expert can supply the jury only with another opinion…”

mowens's avatar

The CIA trains people to beat them….

john65pennington's avatar

Polygraph examinations cannot be beat for this reason. the machine knows if you are high on drugs, high on alcohol or taking blood pressure medication. any of the above will disqualify a polygraph exam(lie detector test).

thriftymaid's avatar

It doesn’t matter if you believe it; it can be done.

DarkScribe's avatar

@john65pennington Polygraph examinations cannot be beat for this reason. the machine knows if you are high on drugs, high on alcohol or taking blood pressure medication.

The machines are beaten regularly – the link in the question is a perfect example. A murderer (who should have good reason to be nervous) beat one during a Police interrogation. As for a Polygraph “knowing”, it doesn’t know anything – it is not sentient. A good operator might guess at drug use, but without drug, urine testing etc., s/he cannot be sure. (There is no way that a polygraph can determine whether a person is taking blood pressure medication without a baseline for comparison.) You seem to have some strange ideas about what a polygraph actually is.

mattbrowne's avatar

Progress is slow, but there is progress. There are interesting developments in airport security. Cameras and software might be able to spot potential terrorists while being asked questions at the check-in counter for example.

Answer this question

Login

or

Join

to answer.
Your answer will be saved while you login or join.

Have a question? Ask Fluther!

What do you know more about?
or
Knowledge Networking @ Fluther