confused wrote on Apr 13^th, 2004 at 6:45pm:


Ah. Thanks for clarifying. Your initial description suggested the examiner hadn't completed the series before showing you charts and overall seemed quite odd.

-Marty

Thank you for your responses.

Anyway,  I  thought I'd clear up a couple things and say that indeed I was hooked up to the finger contacts, two tubes, and the blood pressure gauge.  Also, the examiner wouldn't stop and point at the spikes in the middle of the chart, but afterwards when finished with he chart.

I am pretty sure that there was only a single plot, so maybe it was a composite of the different readings.

As far as possibly being a "prop" chart, that is what I originally thought.  Especially since I was "spiking" the charts on questions that there would be no possible way for me to "fail" and wasn't even nervous or embarrassed about answering.

On the start of the next chart though, I began to get nervous about "well, what if those are my charts, and I really am 'spiking' them?  Those were topics I wasn't even embarrassed about, there is no way I'm going to be able to talk about drug/lifestyle questions without 'spiking' those too."

At this point, I couldn't believe that I might not be able to get a job I've always really wanted soley because a machine didn't "believe" me.  I kept wishing that they would just physically verify my statements by asking anyone and everyone that I've associated with.  Heck, I would gladly point them to all the people that knew the "worst" things about me.

confused,

Your polygrapher lied to you when he told you he was collecting a chart "to see if you could respond to the polygraph." The purpose of this procedure, formally known as the "acquaintance test," but commonly referred to as the "stim (short for "stimulation") test," is to dupe the examinee into thinking that the polygraph can actually detect deception. Everyone is told that they reacted strongly to the number they chose, whether or not they did. It is not uncommon for polygraphers to show the examinee the chart in cases where the examinee really does react strongly to the number chosen.

It is also not uncommon for polygraphers to show polygraph charts to examinees and point to supposed reactions and demand an explanation. However, your account is the first I have heard of a polygrapher showing a subject a chart with only one tracing. The standard polygraph chart includes four tracings: upper and lower pneumo, electodermal, and cardio. Polygraphs with a motion sensor (used in an attempt to detect countermeasures) may have a fifth tracing for that.

It's possible that the polygraph software enables the operator to print out a single tracing rather than all of them. It's also possible that the printouts you were shown (both from the "stim test" and later, during the "in-test" phase) were not actually your own, but pre-planned props. I don't know.

For more on polygraph procedure, see Chapter 3 of The Lie Behind the Lie Detector.

In any event, you'll be glad to know that the Department of Defense's counterintelligence-scope polygraph screening program has a pass rate of close to 100%. Although some individuals may be initially accused of deception and scheduled for a "re-test," virtually the only persons who ultimately fail are those who make "substantive admissions."

confused wrote on Apr 13^th, 2004 at 6:03am:


This would be unusual for a screening polygraph. Normally, metal sleeves are attached to two fingers, a cardio bp cuff to your upper arm, and one or two stretching hoses around your chest/abdomen. The finger sensors detect sweating which decreases your skin resistance, the BP cuff detects both heart rate and blood pressure changes. It is pumped up to a level that partially blocks blood flow. The one or two bands around your chest measure respiration. If all these attachments were made then it is possible that the "chart" you were shown was some sort of composite of the various channels used or perhaps, more likely, just the channel that was responding the most and the polygrapher selected it to go for some sort of confession. 

Interrupting the polygraph part way through a series and confronting you with charts is highly irregular and has been described in polygraph literature (Matte) as not desirable.

-Marty

The polygraph was a pre-employment screening for the
DoD.   

I am pretty sure that there was only a single
plotted line for the chart.  For both the initial test
and the actual questioning afterwards, the examiner
pointed to large spikes on the chart.

I guess my question needs to be added to then, why
would there only be a single line plotted, and why
would there be such a large spike to a question
answered truthfully?

confused wrote on Apr 13^th, 2004 at 12:31am:


First, a polygraph, by definition, measures more than one response. I am unaware of ANY polygraph instrument that only produces a single plot line.

Second, experienced polygraphers will ask questions evenly, without inflection, through a complete series, often multiple series.

What was the general purpose of the "polygraph" you took?

-Marty

I took a polygraph that had a little printer off
to the side of the examiners desk.  Before I took
the test though, he conducted a chart to see if I
could respond to the polygraph.  I guess my body
did and he ended up showing me a printout of a
huge spike on the chart.

Throughout the rest of the actual test though, the
examiner kept showing me charts that I was
"blowing out of the water".  When he would show me
the chart, there would be a single line plotted
with three or four very large spikes on it.  What
I do not understand though is that for a question
I was responding to truthfully, why would there be
such huge responses?  Also, is it typical to have
the charts displayed to you?