Lord_Darkclaw wrote on Feb 10
th, 2007 at 1:07pm:
I read the National Academy of Sciences report, but it doesn't seem to criticize the validity of the polygraph machine - it does criticize the methods of testing, but it does not offer any damning criticsm of the accuracy of the machine.
Dr. Richardson is right, you should really question your reading comprehension ability...
Lord_Darkclaw wrote on Feb 10
th, 2007 at 1:07pm:
What the report gives, is a set of "what if" scenarios - situations in which the test subject may produce atypical responses.
Nope, the NAS gives situations based upon assumed levels of accuracy and the base rate of lying and calculates the predictive value of the test which show that even with an accuracy rate of 80%, the test would falsely accuse thousands of people for every spy it caught.
Lord_Darkclaw wrote on Feb 10
th, 2007 at 1:07pm:
But in testing for responses to specific questions - ie; questions that are not generic - the validity of the polygraph test is not called into question except in regard to countermeasure techniques - techniques which are now limited since the introduction of counter-counter measures (pressure-sensitive seat pads/foot pads etc).
Perhaps you missed the part where the NAS said that only area that the polygraph showed accuracy above chance but well below perfection was with specific incidents with subjects
untrained in countermeasures.
Lord_Darkclaw wrote on Feb 10
th, 2007 at 1:07pm:
So, for me, the question remains: when someone is strapped into a chair; pad on seat, pads under feet, tubes around chest, wires on fingers; can they really beat the test when asked direct questions?
For those trained in countermeasures, the answer is yes.
Dr. Richardson is right, there is no doubt that the polygraph machine accurately measures pulse, blood pressure, respiration, and sweating. And to echo him again, there is serious doubt as to whether changes in these measure correspond to deception.
An analogy to the polygraph would be ghosthunters that use electromagnetic field detectors who claim that when the EMF meter goes off, it means there's a ghost present. Does anyone question if EMF meter detect electromagnetic fluctuations? No, but to make a claim that the fluctuation corresponds to a ghost and not to some other cause such as electrical wiring, magnetized metal, etc., one should have evidence.
The CQT polygraph is seriously lacking in its evidence that it can detect deception because there is not a one to one correlation between lying and changes in physiology because these same changes in physiology can occur from other emotional, physical, and mental conditions. The CQT polygraph has no way of winnowing out these other causes and hence is an unreliable and invalid determination of deception.
In addition, countermeasures are a set of methods that allow individuals to exhibit the expected response for non-deception. How hard is it to believe that one can mimic these responses to beat the machine? This isn't the same as drug testing where one is employing a masking agent, one is merely demonstrating the expected physiological changes needed to demonstrate non-deception.
Again, your purported skepticism belies someone who thinks that the CQT polygraph actually works. A true skeptic would look at the evidence and come to the same conclusion as the NAS which is the CQT polygraph in any screening application is danger to society.