WHAT IS A POLYGRAPH EXAMINATION?

A System To Measure
Physiological Responses
To Psycholgical Stimulus

The term "polygraph" literally means "many writings." The name refers to the manner in which selected physiological activities are simultaneously recorded. Polygraph examiners may use conventional instruments, sometimes referred to as analog instruments, or computerized polygraph instruments.

It may be important to the inquirer to understand what the polygraph examination process entails. A polygraph instrument will collect physiological data from at least three systems in the human body. Corrugated rubber tubes that are placed over the examinee's chest and abdominal area will sense respiratory activity and record it. Two small metal plates, attached to the fingers' tips, will semse sweat gland activity and record it. In addition, a blood pressure cuff, or similar device will placed on the arm and inflated to record cardiovascular activity.

A typical polygraph examination will start with:

1.) Pre-test phase
During the pre-test phase, the polygraph examiner will complete the required paperwork and talk with the examinee about the test. During this period, the examiner will discuss the questions to be asked and familiarize the examinee with the testing procedure.

2.) Chart collection phase
During the chart collection phase, the examiner will administer and collect a number of polygraph charts. This usually begins with an aquaintence test that allows the examinee to experience the instrumentation and for the examiner to adopt to the examinee's individual physiology.

3.) Test data analysis phase.
Following the actual testing, the examiner will analyze the charts and render an opinion as to the truthfulness of the person taking the test. This statement is based on numerical scoring.

The examiner, when appropriate, will offer the examinee an opportunity to explain physiological responses in relation to one or more questions asked during the test. It is important to note that a polygraph does not include the analysis of physiology associated with the voice. Instruments that claim to record voice stress are not polygraphs and have not been shown to have scientific validity.

LINK TO AMERICAN POLYGRAPH ASSOCIATION

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