What is a Polygraph Test / Lie Detector Test? 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 is important to understand
what a polygraph examination entails. A polygraph instrument will collect physiological data from at least three systems in
the human body. Convoluted rubber tubes that are placed over the examinee's chest and abdominal area will record respiratory
activity. Two small metal plates, attached to the fingers, will record sweat gland activity, and a blood pressure cuff, or
similar device will record cardiovascular activity.
A typical polygraph examination
will include a period referred to as a pre-test, a chart collection phase and a test data analysis phase. In the pre-test, the polygraph examiner will complete 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. During
the chart collection phase, the examiner will administer and collect a number of polygraph charts. Following this, the examiner
will analyze the charts and render an opinion as to the truthfulness of the person taking the test.
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 support.
