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Public Servant,

I, for one, have little problem with specific incident testing. Especially given fairly high confession rates. I do have a number of questions though.

1) have you any experience with GKT's?  From what I understand they are dominant in Japan but rarely used in the US and they avoid the issue of a false positive due to fear of consequences.

2) SDPD did a pretty good job with Westerfeld, they tracked down info from his ex that he was violent at times when drunk and used it for a control question. Nice.  They didn't get a confession but he pretty much collapsed.  They also taped the whole thing (yay!). Do you think they might of gotten a confession if they had used a GKT based on details like the house's interior etc. It looked like a ripe candidate for GKT to me and since he was an engineer, he would likely find the results more compelling. If he confessed it would have saved the state millions.

3. Do you think false positives may be more common with forensic polygraph CQT's?  I would think fear of consequences would create quite a reaction among purely innocent examinees. OTOH, you probably could come up with better control questions from the crime investigation than the guys that do screening.

-Marty

Marty,

1.) I have little experience in utilizing the GKT.  I have seen the assertion regarding its use by the Japanese.  I am not sure if this is true. However, I was once told by a Japanese law enforcement officer (not an examiner) that they heard that the type of examinations used in the U.S. did not work on Japanese.  This person was not an expert in the field and I believe did not understand what had been stated by a Japanese examiner.  I believe, however, my acquaintance's examiner friend was alluding to a perceived cultural issue which might hamper the CQT technique.  Purely my take on a brief conversation.

2.) Here's the problem with GKT, as I see it.  First, finding characterisitics of an incident that only the perpetrator knows could be difficult.  Impossible in some instances.  ...More difficult with todays information saturation by media (as high profile cases would be) ...And especially if a thorough interview had been conducted with the suspect prior to offering examination (as usually is the case), and in an effort to give the suspect reason to confess by showing the suspect he is "caught", the interviewer tips his hand on what is known about the incident.

A GKT could also give the suspect "wiggle room" in post-test interview.  He could say he only had tangential involvement and thus knew something about the scene.  And in reality, the examiner would not know if the DI was due to actual perpetration or simply knowledge withheld.  This is what I saw as the weakness to the Brain Fingerprinting Technique espoused by Drew.  It might prove a memory of a fact about the crime scene, but does not put the gun in his hand.  This is why I once asked him about a CNS monitoring technique getting to guilt, not knowledge/memory of characteristics of the incident. When a suspect is DI to CQT, he failed a "did you do it?" question(s).  Claims of other tangential knowledge/involvement can be easily countered by the interviewer, because that was not what he responded to.

3.)  I know that PhD types (actual ones, and those on both sides of the poly debate), advocate the GKT as likely more valid.  I know that research seems easier to conduct in pursuit of validation (see earlier posts of mine in past threads for discussion of difficulties in proving CQT, specifically SI CQT).  However, there is much more room for error in devising a good exam for each specific case (as you could also surmise from the above).   I'd say practicality and cutting to the heart of the matter are why most agencies use CQT for SI exams (again I'd refer to the above).  I could not comment on false positive rates, without sitting down in front of someone else's research (many persons', none of which is mine).

Again these are only my thoughts on the topic.  I have provided them off the top of my head referring to no research literature and on a topic for which I am by no means an authority (I have offered my meager credentials in a previous discussion with Drew, which should serve as sufficient disclaimer).  Hope I addressed them as you wanted.   

Take Care!

Public Servant

Public Servant, 

I am afraid your demonstrated understanding of scientific evidence with regard to polygraph validity and countermeasure efficacy is severely lacking.  Specifically, with regard to the latter, by convention you are blind to 100 percent of all who successfully (and I repeat, 100 percent of all who) utilize countermeasures in your polygraph suite.  Without the benefit of ground truth, you are proving absolutely nothing there by simply performing your duties to the best of your abilities other than perhaps something about time and attendance for your employer’s purposes.  You may have a genuine desire to perform well, hope you have performed well, and in your gut feel you have performed well, but you have demonstrated precious little regarding your ability to detect countermeasures.  The notion that you periodically put forth about polygraphers meeting the challenge on a daily basis in the real world in individual polygraph suites is complete balderdash.  There may well be reasonable ways to do so other than through accepting and performing successfully with my challenge, but the nonsense you have suggested is nothing but either grand self-delusion or a desperate attempt at institutional mis/disinformation.  Largely thanks to George et al your self-delusion will never again be pandemic.

Public Servant,

Thanks for your notes. Kleiner's compilation survey has an article by a Japanese researcher who details the use of GKT's in Japan. I would cite more details but they are not handy. I referenced the book in one of my earliest posts though. It may be that, since the poly did not come into wide use in Japan until long after the US, there was a natural proclivity to utilizing GQT which was widely considered superior by academics, if not pratitioners, and there was not the existance of a trained group reluctant to adopt something unfamiliar.

In any case, the author stated that CQT's were so rare in Japan that most polygraphers had never actually even given  one. Amazing in that the GKT typically takes more preparation and is less widely applicable.

Fascinating dichotomy.

-Marty