What is a Lie Detector Test?

A lie detector test is also known or commonly referred to as a polygraph test or polygraph examination. It is one of the most powerful, robust and useful scientific tools in truth verification or the detection of deception regarding a specific issue, incident or event.

The term “polygraph” derives from the Greek words poly (many) and graph (writing) “many writings”.

A polygraph examination involves an in-depth procedure, using state of the art, computerised equipment and validated test techniques. During an examination, manifestations of a person’s nervous system are recorded from at least three systems in the body.

Two convoluted tubes are placed around the upper chest and abdomen of a person to record respiratory activity. Two metal plates or disposable adhesive electrodes are attached to a person’s fingers to record sweat gland activity and a blood pressure cuff will record cardiovascular activity. A motion sensor will monitor general movements throughout the examination.  A finger plethysmograph may also be used to monitor blood volume.

Voice stress tests should not be confused with a Polygraph Test. The two are completely different tests with voice stress testing working no better that pure chance (i.e. the accuracy of such voice stress instruments are similar to making a decision based on a flip of a coin). We therefore do not use it in our examinations.

An examination should only be conducted by an experienced and trained polygraph examiner.