Welcome to Truth Lab

Lie Detection

The need for truth is basic. Man’s tendency to lie is basic, too.

The first efforts to determine the truthfulness of a situation seem humorous to us now. One of the earliest was "The ordeal of the Sacred Ass" (India).   Suspects were told to walk through a darkened tent containing a donkey and pull the tail of the donkey. They were told that the donkey was a Sacred Ass and that it would bray when the guilty subject grasped it tail.

The Sacred Ass would have lamp black dust on its tail unknown to the suspects.  The innocent suspects would pull the tail as directed and would exit the tent with lamp black on their hands. The guilty suspect, believing in the supernatural, would pass by the Sacred Ass without touching the tail for fear the ass would bray. He would then be judged guilty because of his clean hands.

Today's Polygraph

Today, polygraph is designed to protect the innocent/accused person, as well as discover the guilty. It is a scientific instrument that can be as accurate as 99-100%. The skill of the examiner and the techniques used are important as well.

Humans have a complex, physiological make-up. When we feel threatened in life, it does not matter what the threat is from, it could be a radar camera or a rattlesnake or someone raising their voice but the sympathetic nervous system kicks in and we go into a fight, flight, or freeze mode.  It's our body’s way of defending itself in that given situation.  In this "protective" mode, changes occur in our breathing, heart rate, blood pressure, and sweat glands. 

So when we see the radar camera, we hit the brake.   At the sight of the rattlesnake, we may freeze or run away. The person raising their voice may cause us to try to talk them down, or we may simply get ready to defend ourselves physically. 

How this Relates to the Polygraph

When the polygraph examiner asks a question and the person lies in response, they feel threatened and have a physiological reaction.  They are fearful that the polygraph instrument will detect the physiological reaction they are trying to hide.  The subject knows the truth, and if they try to hide that fact from themselves or their examiner, their body responds with stress … a readiness to run or defend.  The subject's reaction may not be visible to the examiner, but it will be to the polygraph instrument.