Lie Detector Testing

What can I expect from the Lie Detector Testing?

Lie Detector Testing usually takes around 2 hours from beginning to end and consists of three different phases; pre-test interview, collection of charts, and analysis of charts. Lie Detector Testing is the most fool proof method of testing if someone is lying.

Pre-test interview & formulation of questions 
During the pre-test interview the examiner will explain how the lie detector testing works, discuss the issue and develop and review all questions to be asked on the lie detector test. This stage is normally the longest to complete, and will take anywhere between 45 and 90 mins.

Collection of Charts-
During this phase the subject will be attached to the lie detector. The set of questions which were developed during the pre-test interview will be asked 3 or 4 times.

Analysis of Charts-
Once the examiner has collected the charts he will analyse the results before giving a decision as to the subject s truthfulness or deception to the given issue.


What Questions Can be Asked?

The examiner will work with you to construct questions that cover the test issue as well as meeting the strict rules for the latest polygraph techniques.

All questions are discussed with the subject thoroughly before the test commences and will be answered "yes" or "no".

How Does the Lie Detector Work?

The lie detector works by tracing changes in a person s physiological conditioning during questioning. These changes are recorded directly on to the polygraph charts in order that they can be reviewed. Some of the changes that occur may replicate those that have been linked with truth or deception for many years. These physiological changes have been the subject of various research projects and our examiners have undertaken many hours of polygraph chart analysis instruction to interpret them.

The lie detector charts are generated by attaching four components to the subject.

Pnuemograph 
Two rubber pnuemograph tubes are placed around the subject s upper chest and abdomen on the outside of their clothing, these record breathing and movement.

G.S.R 
The GSR or Galvanic Skin Response is produced by placing two finger plates across fingers on one of the subject s hands. These trace changes to the skin resistance during the examination.

Cardiosphygmograph 
This component traces changes to the subjects relative blood pressure and pulse rate and it is similar to the pressure cuff your doctor uses when taking your blood pressure.

After the questions have been asked with the subject attached to the polygraph the examiner will read the generated charts to establish truth or deception. The agreed questions will always be asked at least twice.


How reliable is lie detector testing?

There is no doubt that the polygraph is highly reliable, providing the person using it is properly trained and the technique they use is validated. The American Polygraph Association (APA) has gathered over 200 studies on the subject, you can view further information at their web site www.polygraph.org

At Distress services, we specialise in Lie Detector Testing.