Polygraph

The polygraph is a just what the name says. "Poly" meaning "many" and "Graph" we all know what a graph is. A polygraph is a simple machine with many graphs. These graphs monitor what is called physiological indices which are: blood pressure, pulse, respiration, and skin conductivity (sweat). 
I must first state that this is not a device designed to detect deception, but it is only used for that. It is in fact no different than the normal blood pressure monitor. The only difference is that it can monitor a couple things simultaneously. Another name for this device is psychophysiological detection of deception (PDD) I am going to call it a PDD (shorter to type than polygraph).

The person controlling the PDD is called a "Polygrapher". He is trained in the skill of understanding how humans react to questions. There are a few ways to use a PDD. I am going to talk about the most common way; the CQT (Control Question Test). But before we get ahead of ourselves, let’s go back a bit.

Let’s say that you are being interrogated, while hooked up to a PDD. There are 3 main phases a Polygrapher goes through in the full test.

1. Pre-test.
2. In test.
3. After-test (I am not sure about the last part but it does exist)


Ok, let’s start. In the pre-test, there is no actual lie detection going on. In fact, this phase is all about mind games. Let me give you an example... Very few people know what the exact capabilities of a PDD are, and how it works. But in this phase the Polygrapher basically lies to you about its capabilities. He does this to get your mind into the state of knowing "I can't fool him", and by knowing that, you give much more reaction to his in-test questions. Let’s see how this pre-test is done.

The Polygrapher shows you a deck of cards it just looks like a normal deck. He shuffles the deck and tells you to take off the top card. You see that it is a 2 of spades. But he doesn’t know that. So he proceeds to ask you the following questions, you answer NO to all of them

Is it a face card? (No)
Is it a number card? (No)

Then he says: "It is clearly a number card"

Is the number, one? (No)
Is the number, two? (No)
Is the number, three? (No)
Is the number, four? (No)
Is the number, five? (No)
Is the number, six? (No)
Is the number, seven? (No)
Is the number, eight? (No)
Is the number, nine? (No)

Then he says: "It is clearly a two"

Now he asks:

Is it Diamonds? (No)
Is it Spades? (No)
Is it Hearts? (No)
Is it Clubs? (No)

Then he says: "You picked a two of Spades"

You know he is right, but what you don't know is that the deck was fixed. All of the cards are two of spades. It was a Svengali deck (used in card tricks to make all the cards look the same.)

Now you "think" that he is good, and that he easily found out when you were lying. Your body will now stress more if you tell a lie.

Now we move on to the in-test phase.

There are 2 types of questions asked here.
1. Control
2. Relevant

He asks the control questions to establish a base line. As I said in the post about body language: There must always be a base line to work from.

The control questions are known to be true, like:

Is your name Hanno Lambrechts? (Yes)
Are you currently 16? (Yes)
In what school are you? (Home Schooling)

If the Polygrapher ask me this, and those were my answers, he would see my base line of telling the truth. While he knows my base line, he proceeds to ask me relevant questions:

Did you kill William Anderson? (No)
Do you know who did? (No)
Do you sometimes spy on your cat? (Skip that, it’s dumb)

Then the Polygrapher look for deviations in your baseline to determine which answers was a lie.

Now, let’s have a look at the after test.

The Polygrapher says that he got all he needs. But he keeps monitoring. Now that you are relaxed, he looks for a rapid change in the base line to see if you tried to counter. And to counter the polygraph is easier than you think.



Maybe I will do another post on how to counter the PDD. But I hope that you now know how it works.

For interest sake, a good person to look into is: Aldrich Ames. He was a spy from the KGB who was inside the CIA. The KGB trained him to counter the polygraph.

http://en.wikipedia.org/wiki/Aldrich_Ames