If Sheila Did It

[TheBrilliantMistake]

Would anybody here put their faith in a lie detector test if it was their life depending on it?

There's not big red light saying "lie", it's interpretation.


As silly as this may sound, it's like ABS on your car... it's quite good, and it can detect your wheels spinning, but it can't be sure WHY they are spinning...
In many instances it will give you the right results, but depending who's driving, it can give precisely the wrong results too.

At it's very basic level, lie detectors ALL work on the premise that when you lie, there are physiological changes in your body. The difficulty with this can be that some people don't even know they are lying, and others start to lie so much that 'lying' is not a new state for them it becomes the norm.

Many people DO exhibit physiological changes when lying - can't be denied. But the changes vary from person to person, and the levels of change are different from person to person.
However, being late for a meeting can cause physiological changes in people too. Likewise, being questioned about uncomfortable issues can affect you.

That does not mean if you sweat you must be late for something. If your GSR changes, it doesn't mean you're lying. It could be an 'indicator' that's all.

There's a final problem too... certain types of killers are able to divorce their emotions from their actions in a way the majority of us cannot - the ability to convincingly lie can be far less about 'technique' as their own belief in what they say. Once a person fails to differentiate fact from fiction in their own mind, no amount of physiological testing will detect a change.

Basically, it's useful, but no more than that.

[Roch]

Would anybody here put their faith in a lie detector test if it was their life depending on it?

There's not big red light saying "lie", it's interpretation.


As silly as this may sound, it's like ABS on your car... it's quite good, and it can detect your wheels spinning, but it can't be sure WHY they are spinning...
In many instances it will give you the right results, but depending who's driving, it can give precisely the wrong results too.

At it's very basic level, lie detectors ALL work on the premise that when you lie, there are physiological changes in your body. The difficulty with this can be that some people don't even know they are lying, and others start to lie so much that 'lying' is not a new state for them it becomes the norm.

Many people DO exhibit physiological changes when lying - can't be denied. But the changes vary from person to person, and the levels of change are different from person to person.
However, being late for a meeting can cause physiological changes in people too. Likewise, being questioned about uncomfortable issues can affect you.

That does not mean if you sweat you must be late for something. If your GSR changes, it doesn't mean you're lying. It could be an 'indicator' that's all.

There's a final problem too... certain types of killers are able to divorce their emotions from their actions in a way the majority of us cannot - the ability to convincingly lie can be far less about 'technique' as their own belief in what they say. Once a person fails to differentiate fact from fiction in their own mind, no amount of physiological testing will detect a change.

Basically, it's useful, but no more than that.

Good post. Though I'd like a 2nd opinion on that TBM. Maybe the forum could attract an independent expert on such technology and testing, if they exist.  In the case of JB, I suppose some might point to certain aspects / perceived aspects of his actions / demanour after the killings to argue that he falls in to your 'detached' category. However, I'm not aware of psychological testing of JB while he's been in prison that would indicate such a personality. But then i only have the info on his official site in that respect.  I'm stealing my own thunder here, coz i said i wanted to put a thread on 

[TheBrilliantMistake]

To make matters worse...

Eye witness statements are quite lousy too.

You really would not believe how inaccurate they are. Worse still, although not deliberate, you need to get eye witness statements before they even talk to each other... the moment they talk, their statements start to converge (natural phenomenon)

I mean most people will be able to say "I saw Jeremy climbing through the window"
But 10 minutes later, some will say it was a different window, some will say he was wearing jeans and some will say trousers. Some will say they heard 5 shots, some will say 3 and some 7. Some will say the window was already open and some say he seemed to have to leverage it.

Some really significant 'memorable' (you'd think) elements get completely screwed.

[mb1]

To make matters worse...

Eye witness statements are quite lousy too.

You really would not believe how inaccurate they are. Worse still, although not deliberate, you need to get eye witness statements before they even talk to each other... the moment they talk, their statements start to converge (natural phenomenon)

I mean most people will be able to say "I saw Jeremy climbing through the window"
But 10 minutes later, some will say it was a different window, some will say he was wearing jeans and some will say trousers. Some will say they heard 5 shots, some will say 3 and some 7. Some will say the window was already open and some say he seemed to have to leverage it.

Some really significant 'memorable' (you'd think) elements get completely screwed.

A colleague and I witnessed someone behaving strangely near public restrooms in a government building. A replica gun was found in a cistern.
Anyway, my colleague and I gave completely different descriptions and each voiced disbelief as the other relayed what they'd seen. Age was a huge bone of contention. The security officer decide to separate us!
Lord help anyone trying to draw a sketch...