Serial killer passed polygraph. Will it ever sink in?

[hgc]

From this article.

But Ridgway told police he didn't know Malvar, and investigators cleared him as a suspect. Later that year, Ridgway contacted the King County sheriff's Green River task force — ostensibly to offer information about the case — and passed a polygraph test.

How many times do we have to hear about guilty people who have passed polygraphs, or vice versa, before public policy makers start to figure out that polygraph does not equal lie detector?

 

[Nyarlathotep]

It might sink in eventually but I don't think it will in the near future. The pollygraph is an idea that seems logical and scientific so even a lot of people who wouldn't believe in something like ESP will believe in the efficacy of the polygraph. Further, the media tends to trot out polygraph examinations as if they actually prove something, that doesn't help either.

However, it seems to me that a lot of people I know are aware of the fact that a polygraph examination doesn't mean anything so I think the message is getting out, if slowly.

 

[Crossbow]

Wow!

A while back I got to meet and talk to a police officer who did a great deal of work with polygraphs and he told me that they were such a good tool for investigations. I was not so sure since I was aware of some of the problems with polygraph machines, but I did not debate the point too seriously.

I hope that he sees this news.

 

[CFLarsen]

The pollygraph is an idea...

Polly have a cracker? (Sorry...)

 

[hgc]

Wow!

A while back I got to meet and talk to a police officer who did a great deal of work with polygraphs and he told me that they were such a good tool for investigations. I was not so sure since I was aware of some of the problems with polygraph machines, but I did not debate the point too seriously.

I hope that he sees this news.

That's what I'm talking about. We see these type of news items over and over again. Example after example of polygraph giving the wrong result. But people, and particularly in law enforcement, still believes in it. I'm not saying that anecdotes of faulty readings proves that it doesn't work. But we know that it's never been shown to work, and also why it's not likely to work (requirement of interpretation by examiner).

 

[Nyarlathotep]

Polly have a cracker? (Sorry...)

Oops. I am concentrating on other things and making even more than my usual number of typos today.

It is funny though, I suppose a pollygraph is waht you chart the number of parrots that you own on.

 

[Tez]

One of the more interesting things that comes out of left brain/right brain research is that different pieces of your brain become active when creating something versus when recalling something. I wonder why we don't use this to make a polygraph that actually works. Given the sort of things one reads at http://www.antipolygraph.org/ I'm not inclined to put any faith in regular polygraphs whatsoever...

 

[specious_reasons]

Wow!

A while back I got to meet and talk to a police officer who did a great deal of work with polygraphs and he told me that they were such a good tool for investigations. I was not so sure since I was aware of some of the problems with polygraph machines, but I did not debate the point too seriously.

I hope that he sees this news.

The polygraph is a good tool for criminal investigators, because they can use it to drag a confession out of an uninformed criminal. It's psychological leverage.

"We know you're lying. You failed your polygraph test. It's only a matter of time. If you confess now, we'll make you a deal."

What it's not good for is actually detecting if a person is lying.

 

[Tmy]

Why would anyone take a lie detector test. It cant help you. Its not admissable in court and you either fail, or get "inconclusive". Then theres the questions asked, that can affect things.

Arent there ways to cheat at lie detectors. Like holding your breath, stepping on a tack in your shoe (your reaction to pain screwes with the test). I have an irregular heartbeat, woudl that mess up the test.

 

[hgc]

Why would anyone take a lie detector test. It cant help you. Its not admissable in court and you either fail, or get "inconclusive". Then theres the questions asked, that can affect things.

Arent there ways to cheat at lie detectors. Like holding your breath, stepping on a tack in your shoe (your reaction to pain screwes with the test). I have an irregular heartbeat, woudl that mess up the test.

A polygraph can benefit you if a) you're guilty, b) you can pass and c) investigators believe it's a lie detector. Hell, could be good if you're innocent, but then you risk failing.

 

[hgc]

The polygraph is a good tool for criminal investigators, because they can use it to drag a confession out of an uninformed criminal. It's psychological leverage.

"We know you're lying. You failed your polygraph test. It's only a matter of time. If you confess now, we'll make you a deal."

What it's not good for is actually detecting if a person is lying.

I'm in favor of the police exploiting the ignorance and misconceptions of the general population to get legitimate confessions, but then I have to balance that against my desire to see ignorance treated and cured.

 

[pgwenthold]

Why would anyone take a lie detector test. It cant help you. Its not admissable in court and you either fail, or get "inconclusive". Then theres the questions asked, that can affect things.

Read the original article above for your answer. He was a suspect, but then passed a polygraph, and they dropped him from the suspect list.

Sounds like a great reason for a guilty person to take it to me.

OTOH, if you are innocent it is not as helpful.

 

[epepke]

A while back I got to meet and talk to a police officer who did a great deal of work with polygraphs and he told me that they were such a good tool for investigations. I was not so sure since I was aware of some of the problems with polygraph machines, but I did not debate the point too seriously.

I hope that he sees this news.

I don't see the problem here.

1. Polygraphs are excellent tools for investigations.
2. Polygraphs are next to useless for determining whether someone is telling the truth.

These two statements do not conflict. In fact, statement 2 supports statement 1.

If this person sees the news, he will no doubt conclude that polygraph examinations should be tougher.

 

[MoeFaux]

Not only is the polygraph test bullsh*t, it depends on the test giver. Your innocence could depend on whether or not someone likes the way you look. It's appalling.
I'm hoping P&T do a bit on it in their 2nd season.

 

[a_unique_person]

IIRC, a polygraph depends on the person being tested reacting to questions in a way that indicates stress, from feelings of guilt or fear of being caught.

A serial killer like this guy has no conscience, it doesn't bother him at all.

 

[Tricky]

IIRC, a polygraph depends on the person being tested reacting to questions in a way that indicates stress, from feelings of guilt or fear of being caught.

And because of this, the only way a person can be intimidated by a polygraph is if that person believes that the polygraph works. Thus, a person who realizes that the polygraph is worthless is not going to be caught by it. It is also pretty much worthless for the type of criminal who has convinced himself that he is without blame. He may lie with a clear conscience, knowing that he is doing "the right thing".

So it only works for criminals with a strong moral code. Actually, there probably are a fairly large number of these, but the truly heartless criminals (like serial killers) are not among them.

A serial killer like this guy has no conscience, it doesn't bother him at all.

My point exactly.

 

[Abdul Alhazred]

How many times do we have to hear about guilty people who have passed polygraphs, or vice versa, before public policy makers start to figure out that polygraph does not equal lie detector?

The current USA policy is that police cannot require a polygraph, but that an alleged perp can volunteer to clear himself. That's what happened here.

An exception is made for security clearances and national security matters.

The position seems to be that the polygraph really works, but that the Fifth Amendment prevents its imposition in ordinary criminal matters.

Sheesh! We might as well trust our national security to Tarot card readings.

 

[Abdul Alhazred]

Wow!

A while back I got to meet and talk to a police officer who did a great deal of work with polygraphs and he told me that they were such a good tool for investigations. I was not so sure since I was aware of some of the problems with polygraph machines, but I did not debate the point too seriously.

I hope that he sees this news.

Well, from a cop's point of view it might be of use as a bluff to extract a genuine confession.

This is possibly apocryphal, but there was a story going around when I was growing up about a New York City cop who got a confession out of a particularly stupid perp. The cop put the perp's hand in a photostat machine and told the perp it was a lie detector.

For you young'uns, a photostat machine was like a photocopier, but it made a negative copy so you had to run it though twice. Not as commomly used as photocopiers are now.

 

[CFLarsen]

One of the more interesting things that comes out of left brain/right brain research is that different pieces of your brain become active when creating something versus when recalling something. I wonder why we don't use this to make a polygraph that actually works. Given the sort of things one reads at http://www.antipolygraph.org/ I'm not inclined to put any faith in regular polygraphs whatsoever...

I doubt it would work anyway. We know that we can fool ourselves into believing that fictional events have actually happened. Wouldn't that result in the "recall sections" being activated instead of the "creative" ones?

Apart from the polygraph (it is wrong to call it a "lie detector", since it cannot detect lies), the brain research sounds very interesting. Amazing what science can tell us...