Product: Lie Detector
Polygraph Photo ID   (+3, -2)  [vote for, against]
"Just relax and look at the faces"

Victims of violent crimes may be asked to pick out the perpetrator from a book of arrest photos or examine composite pictures ('photofits') to find a similar face. These are both conscious processes and will be subject the limitations of conscious recall as well as being repressed by certain stress reactions of the brain.

What if we could tap into the unconscious memories, unfiltered by expectations, predudices and the stress repression of the experience of the crime. Maybe we can.

During a polygraph photo ID, the witness would be hooked up to a variety of biometric sensors that together form a polygraph or 'lie detector'. Polygraphs work by looking for stress reactions so this should be just what we are looking for. The witness would then be shown a set of pictures, or a gradually evolving photofit while trained operatives examine the sensor feedback and talk to the witness to eliminate false positives.

[changed 'serious' to 'violent' as that is what I meant in the first place.]
-- st3f, Dec 20 2005

I once saw on television a set up in which a woman caused a scene and a man ran away with her hand bag, Derren Brown then asked a spectator to consciously recall the thief. He then put her into a trance like state and she unconsciously recalled the perpetrator - giving a lot more details than she was previously able to. Of course I can't vouch for exactly how honest the show was, it could have all been a set up, but it just goes to show.
-- fridge duck, Dec 20 2005

It's equally easy to implant false memories this way. inadvertently or not.
-- DrCurry, Dec 21 2005

doesn't a lie detector only woik on conscious thought processes?

+1 'cos its you, 'cos its christmas and 'cos its interesting.
-- po, Dec 21 2005

Polygraphs take biometric readings. The stress patterns of lying are the axis of a lie detector test. The stress patterns of the remembering a traumatic incident would be used as an axis here. Note that I am only suggesting the use of the polygraph on victims of crime, not passive witnesses, as passive witnesses might not have a stress reaction associated with the crime.

Say the victim has a stress response to photographs of people with goatee beards yet does not remember the perpetrator of the crime having one. It is possible that the victim has some other memory associated with a man with a beard. It is also possible that the attacker had a beard and that the victim has not consciously remembered that fact.

I guess this is where DrC is coming from. If the victim is not carefully interviewed and the results treated as facts rather than possibilities then it is possible that police would arrest a man with a goatee beard, not because he attacked the victim, but because the victim was beaten by their uncle as a child and the uncle had a goatee beard.

I'm not suggesting that this is an automatic solution. I'm suggesting that it might be a tool. Like all tools it would have to be used with skill to obtain good results.
-- st3f, Dec 21 2005

I personally don't think this will work. It follows the same methods as lie detecting, and lie detectors haven't become institutionalised into criminal law or anything, and are mostly seen in movies. There's a reason for this; most likely lie detectors are very fallible. So why would you want to institute a method of criminal identification that is easily fallible?

If this does get intergrated into the system, then plenty of innocents will get locked up just because the witness identifying them had a bowel movement, or something. [-]
-- Honduras, Dec 21 2005

I've never seen a real ID parade, but I often wonder if they could be made more dynamic (for want of a better word) and more natural, to see how the person moves or holds themselves, cues which we often unconciously take in. Maybe CCTV footage of the parade members arriving could be replayed.
-- coprocephalous, Dec 21 2005

"'He... he had a rose in his teeth, sarge.'"
-- po, Dec 21 2005

I was in a line-up once. It was a farce as the victim knew the accused before the crime took place. At the time I thought that the police had not interviewed the victim sufficiently to find this out. Later I realised that it might be a tactic to get the accused to confess and save police time. I never found out.

I've also been the victim of a mugging (some years back). At the trial, nearly a year after the crime, I was worried about not being able to confidently identify the accused. Because a witness had turned up, he decided to plead guilty and I was around for a quick discussion between the lawyers before they went into court.

When I saw the man and heard his voice I had a huge stress reaction. It was as if every hair on my body wanted to stand on end. I couldn't breathe and my body stiffened ready to attack or be attacked. It only lasted a couple of seconds but it is this reaction that has me convinced that the idea has at least a chance of working.

po: A rose you say?
-- st3f, Dec 21 2005

Interesting, [st3f]. Of couse, it would have to be done in a way which minimized the pressure and stress that the victim was put under, which is kind of tricky with a polygraph attached to you. But it's a very interesting thought, so +
-- moomintroll, Dec 21 2005

yeah, Nobby said so!
-- po, Dec 21 2005

random, halfbakery