187Dick wrote on Apr 1
st, 2006 at 11:10pm:
Sergeant,
There is a flaw to your logic. Using that logic, we could say that the judicial system in the United States is flawed because innocent people have been inprisoned; therefore, we should abandon the system and just rely on what? God to administer justice?
You could also say that doctors misdiagnose illnesses all the time (I'd venture that this is much more common than false positives in the polygraph field); therefore, we should do away with the medical profession and just let our bodies heal themselves.
Now we could argue statistics back and forth, and both of us could provide numbers from reliable and valid studies to show the effectiveness of the polygraph, but I believe the debate is weakened. I prefer a common sense approach. The problem is how do you know when someone is lying about an important issue. One of the solutions is to use an istrument that has proven the abiltiy to detect physiological changes in a persons body that are related to the fear of detection of deception. It may not be perfect, but there is nothing else that comes close. Your solution is to abandon the practice because it is not perfect and I disagree with that logic as I pointed out. I see it as a tool that is very useful when used properly by a well trained and ethical examiner.
I am not yet ready to let everyone out of prison because the criminal justice system is not perfect.
Rather than changing the subject and getting into the criminal justice system and the medical profession, let’s try to stay on the topic of the polygraph.
I applaud your suggestion to use a common sense approach in the debate on the validity of the polygraph. Let us endeavor to do so. My suggestion was not to scrap the polygraph because it has not achieved deception-detection perfection; it was to scrap the polygraph because it does not work at all.
Looking at it from a common sense perspective I don’t see how you can argue in favor of using a deception detection system that does not, in fact, detect deception.
As an intimidator used to scare people into making a confession, the polygraph performs admirably if the person being interrogated believes it is capable of detecting lies. If they do not believe that then the polygraph is worthless in that regard.
When used as a device used to measure a subject’s heart rate, respiration rate, and galvanic skin responses, the polygraph functions admirably in that regard as well. Does that correspond with an ability to detect deception? Not according to me, not according to many others on this site, and not according to the Office of Technology Assessment or the National Academy of Sciences.
Falling back on the argument of, “It may not be perfect, but nothing else comes close” is what is truly flawed. When assessing the validity of any system or tool the only common-sense way of doing so is to determine if and how well the system or tool performs its assigned function. If it does not do so (like the polygraph and its inability to detect deception) then it is wholly irrelevant how much better or worse it is than other systems or tools that likewise fail to perform the same function.