The question of the polygraph?

[mercury]

Several press organisations reported them as agreeing to do so should the PJ request it.

But theres no  evidence a) they were asked or ever would have been or b) accepted so yes,..,press organisations John

[Alice Purjorick]

If the McCanns had taken a polygraph test and it showed they were not lying would .......................?
They didn't take one so all else is speculative opinion, perm any one from about a dozen  *&*%£

[Alfred R Jones]

If the McCanns had taken a polygraph test and it showed they were not lying would .......................?
They didn't take one so all else is speculative opinion, perm any one from about a dozen  *&*%£

Rubbish.  It is a fact that had the McCanns taken and passed a polygraph test, those who are convinced they hid their child's body would remain convinced that they were right.  No one is honest enough to admit it however.

[Mr Gray]

Rubbish.  It is a fact that had the McCanns taken and passed a polygraph test, those who are convinced they hid their child's body would remain convinced that they were right.  No one is honest enough to admit it however.

Precisely, had the mccanns taken the test and been exonerate all those championing the test here would then be telling us how unreliable they are...

[Carana]

In fact it is possible to test the efficacy of polygraphs, but the trouble is such experiments are rare – at least according to Richard Wiseman, professor of the public understanding of psychology at the University of Hertfordshire. Because you can’t simply ask a criminal whether he was lying or not, the only method would be to use polygraphs in cases where the true answer had already been established using other evidence. Then it would be possible to check the polygraph’s responses against reality in a high-stakes situation. “If the examiner was unaware of the true answers, then that would be a proper double-blind scientific study. But there have been very few trials like that,” says Prof Wiseman.

From what evidence there is, he adds that “the polygraph seems to be very good at catching liars. But it seems very likely to give false positives as well, to 'catch’ people who are telling the truth”.

Horder agrees, pointing to research which found that polygraphs were “70-97 per cent accurate for people who turned out to be guilty, but between 12-94 per cent accurate for people who turned out to be innocent

so between 12 and 94 % accurate when the suspect is innocent

Interesting, thanks.

I can see a use by police as intelligence, but not as evidence. A bit like dogs barking.

[G-Unit]

The error rate for false positives against an innocent person is quite high.....for that reason I would say the test would have proved nothing

Me too lol.

[Mr Gray]

Me too lol.

We actually agree on something... That's quite interesting

[mercury]

Interesting, thanks.

I can see a use by police as intelligence, but not as evidence. A bit like dogs barking.

not quite the same there carana, as dogs are more reliable than polygraphs and proven to be so and not by "chance"

[John]

The only reason the US authorities use the polygraph is to scare suspects into admitting things they might not otherwise do.

[Carana]

The only reason the US authorities use the polygraph is to scare suspects into admitting things they might not otherwise do.

And in some cases, they've announced to the media that they'd failed, haven't they?

[Carana]

not quite the same there carana, as dogs are more reliable than polygraphs and proven to be so and not by "chance"

Not necessarily, IMO. Both could be used as bluff to get someone to confess.

In either situation, there could be innocent reasons for reactions. The point, I would have thought, would be to probe further and find actual evidence.

[mercury]

Not necessarily, IMO. Both could be used as bluff to get someone to confess.

In either situation, there could be innocent reasons for reactions. The point, I would have thought, would be to probe further and find actual evidence.

Oh purleease, you think police use dog alerts as bluffs? That is just not possible unless police dont believe the dog alerts mean anything
And well yes, probe further is the key isnt it ie which means both tests and dogs mean something, no?

[pathfinder73]

Wasn't he already in prison when he offered to do a test?

Yes and he was still claiming his innocence (everyone in the village loved Adrian!) and wanted to do the test to prove it but he failed. That lie detector found Kate's body.

[Alfred R Jones]

Yes and he was still claiming his innocence (everyone in the village loved Adrian!) and wanted to do the test to prove it but he failed. That lie detector found Kate's body.

So he didn't have as much to lose as someone who has not been charged with any crime, in fact he had an opportunity of using the test to convince people of his "innocence" - anything's worth a try I suppose.

[pathfinder73]

So he didn't have as much to lose as someone who has not been charged with any crime, in fact he had an opportunity of using the test to convince people of his "innocence" - anything's worth a try I suppose.

No he was convicted and jailed for life without the body. He was still claiming he was innocent in jail and after he failed the lie detector he confessed and showed where he had hidden the body.

Debbie Garlick who began dating Prout a year after he murdered Kate had launched a campaign to win his freedom.