Mercible wrote on Oct 31
st, 2005 at 7:03pm:
Darkcobra states that the output of the machine can indicate stress. I think we can all agree that his statement is true, at least I didn't see anyone who opposes that statement.
I wouldn't disagree that reactions recorded by a polygraph
can be indicative of stress, but reactions might also be attributable to emotions such as fear, anger, or embarrassment or they could be the result of purposeful manipulation by the examinee.
Quote:So, now it boils down to whether the indication of stress on the charts can be reasonably interpreted to find a person deceptive or truthful.
It can't. The examiner has no way of knowing what caused a reaction. There is no "Pinnochio response" measurable by the polygraph that people produce only when they answer a question deceptively.
Quote:So, it's time to use another analogy. Navy submarines use sonar. If you have ever seen the output of a sonar system, it looks much like a bunch of garbled static on a screen. To the untrained eye, this waterfall display looks really neat, but doesn't mean a thing. With just a "few months of training" a sonar technician can use the data on the screen to draw conclusions about the output. What kind of contact they are seeing, man-made or natural. Whether the contact is on the surface or submerged. Where the contact is located, what speed and heading the contact is on. They can use a sophisticated computer to help them identify which ship they are looking at too. Yet, even this multi-million dollar system is not 100% accurate and the consequences of "getting it wrong" are much more dire than that of a botched polygraph exam.
So why do I use this analogy, you ask? Because, similar to polygraph, this interpretation of what appears to be nonsensical visual data is really more art than science. Even though a sonar technician only has a few months of in-class training, it takes a few years of patrols for a sonar tech to truly be competent. In other words "Experience" is needed. Even then, some sonar technicians are horrible at the job. They just don't have the knack for this kind of thing.
Your analogy is a false one. The principles of underwater sound propagation and the variables affecting it, such as pressure, temperature, and salinity, are well understood, and logical inferences can be made based on the data collected by active and passive sonar systems. The same is not true with regard to polygraphy, where 1) the psychophysiology of human deception is not well understood and 2) there is no clear correlation between the data collected by the polygraph instrument and lying.
Attempting to infer truth or deception by examining polygraph charts is more akin to trying to assess a person's character by feeling bumps on the head (
phrenology).
Quote:I put forth that an examiner, even with in-class training still has to have some real world experience and must be naturally inclined to this kind of work. I would submit that the vast majority of examiners don't fall into this category and therefore are the root cause of the problems you see with the exams. They simply cannot use the "wavy lines" on the page to draw a reasonable conclusion, much less an accurate conclusion.[/url]
The problem is that the underlying procedure is without validity.
[quote]I would submit to you that there are a few examiners out there who do have what it takes. They have real world experience both before and after polygraph school as well as a natural inclination to "reading" people. I don't think that kind of thing can be taught.
It has not been established that an interrogator who consults polygraph charts makes better determinations of truth versus deception than an interrogator who doesn't.
Quote:George, I think that you would be that kind of person. Because of your background in interrogation, you naturally know how to read people. You would know how to prepare a subject for the exam. You would know how to get them to focus on the relevant information. When you saw the "stress" reaction on the chart, you would not immediately assume the subject was lying to you, instead you would know how to properly probe for additional information to either account for or discount the reaction.
My experience at the poker table has given me a healthy skepticism regarding my ability to read people. And again, with regard to reactions on polygraph charts, there is simply no way of knowing what caused them. Moreover, it is wrong to assume that the absence of a reaction means the subject is telling the truth (a notion implicit in your post).
Quote:As stated in my earlier post, the medical community does not rely on a single medical test to make a diagnosis. One test simply becomes an indicator of something that needs to be further examined. A series of tests may need to be conducted to finally come to a reasonable diagnosis. Even then, they are sometimes wrong too.
As previously discussed, polygraph "testing" bears no semblance to medical testing. As with your sonar reference, you again make a false analogy.
Quote:In conclusion, I believe that the "machine" in the hands of the right person CAN be used to accurately detect deception. Even then, a further examination through interrogation, background check and other resources should be used to verify a "reaction" on a chart.
And I believe that astrological charts, in the hands of the right person
CAN be used to accurately predict the future. Even then, a further examination through
cold reading and other resources should be used to verify the results.
Okay, I don't really believe the foregoing. The point is, how does one identify the "right" person of whom you speak?