How does a lie detector test work is one of the main questions our clients ask, so here we have given a brief synopsis as to how it works and an insight as to each of the four phases which form a Lie Detector Test.
The lie detector test records manifestations of a person’s nervous system from at least three systems in the body whilst questioned about concerns of a specific issue, incident or event. The examiner will analyse the charts collected and render an opinion as to the persons truthfulness.
A polygraph examination consists of four phases and will typically take between 2 to 3 hours to complete.
The four phases of a polygraph examination are known as the pre-test, chart collection, test data analysis and finally the post-test phase.
Pre-test phase.
During the pre-test, the examinee is required to complete a consent form and medical form.
The examiner will provide the subject with an overview of the examination and testing process and conduct a pre-test interview. The interview will provide the examinee with an opportunity to discuss their circumstance with the examiner in greater detail and to assist with test question construction. It is imperative to be truthful, open and honest with the examiner as any undisclosed information may affect the outcome of the test results.
Chart collection phase.
Sensors will be attached to the subject and the test questions reviewed. The examiner will go onto administer and collect a number of charts. The number of questions asked and charts collected will vary depending on the format of the test used and the test technique.
Test data analysis phase.
On completion of the chart collection phase, the examiner will review the data collected and analyse the charts. An opinion of the examinee’s truthfulness regarding the specific issue, incident or event will then be rendered.
Post-Test phase.
The examiner will provide the examinee with a verbal result and where appropriate the examiner will offer the examinee an opportunity to explain physiological responses to the questions presented during the test.