Brian Kennedy, N Yorks asked:
Would someone with a psychiatric disorder be better able to pass a lie detector test as they may not feel remorse?
We put this to Jim O’Shea, Intelligent Systems Group, Manchester Metropolitan University:
Old-fashioned lie detectors like the polygraph only detect stress. If the lack of remorse meant that the interviewees had reduced stress levels that would help them pass. Our lie detector, Silent Talker, makes its judgement on non-verbal behaviour: crudely what people call body language. Silent Talker can detect stress but lying involves other factors. We can only juggle a certain number of mental variables at once while we’re thinking. If we’ve got to try and maintain a whole load of different factors about an imaginary story it’s very difficult to do all the mental processing to keep that consistent. That’s what’s known as having a high cognitive load which affects non-verbal behaviour. Also duping delight occurs when liars get a kick out of getting a lie across successfully and again this affects non-verbal behaviour. In one of our own experiments on the general population we taught silent talk to recognise guilty feelings the participants felt while they were lying. When we added this information to the general lie detection we got more accurate classifications. In another independent study conducted by a different university using Silent Talker it was found that Silent Talker was effective at detecting lies told by psychopaths in interviews. So there we have it: evidence that remorse is a factor in the general population but also evidence that in the case of one disorder it’s not the only factor.
A person with antisocial personality disorder (sociopath) would not feel remorse about committing an offence, but could be anxious about facing the consequences of their actions (e.g. imprisonment), the physiological signs of this anxiety could be detected on a polygraph (lie-detector) .
Disorders that manifest delusions may be advantageous to overcoming a polygraph. JnA, Wed, 26th Nov 2008
I'm sure that it's possible to train yourself to deceive a lie detector test.
They have tested this with people that done especially savage and disgusting crimes.
It's actually very easy to fool lie detector tests. I've done it countless times. I'm not sure I should disclose how. DoctorBeaver, Wed, 24th Dec 2008
There has been a recent Swedish research in which they have tested different lie detecting techniques. All failed:) http://www.thelocal.se/17188/20090127/ What is true is more like that samurai movie. Where, if four people, there will be four versions.. And this problem is an important one. Yoron, Fri, 30th Jan 2009
An Israeli manufacturer of lie detectors has threatened to sue researchers from two Swedish universities who collaborated on a study concluding that lie detector tests are useless.
If Nemesysco don't like it, they should publish research showing that their contracptions work not just try to silence the researchers. DoctorBeaver, Sat, 31st Jan 2009
Tut-tut Nemesysco. Chemistry4me, Sat, 31st Jan 2009
My ex-husband sexually abused my daughter and admitted it to me after I found out. We even took pictures of the bite marks he left on her. Yet, he has managed to pass a lie detector test. How is something like that possible? Troubled, Fri, 27th Feb 2009
My husband passed a lie detector test when I thought he was cheating. There were huge red flags and I've had some confessions also, which he then says are not true and he is saying it cause that is what I want to hear. My instincts tell me he did cheat, those confessions were some what truthful and so therefore, these lie detector tess don't work. I truly believe my husband may be a sociopath also. He never shows emotion. Disillusioned, Tue, 16th Mar 2010