What is a Polygraph?
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
According to the dictionary the polygraph is a measuring device, which makes a permanent recording of various physiological changes taking place within the body of the test subject as a result of certain psychological stimuli. These stimuli are brought about by asking questions, structured and phrased in a specific way, and by maintaining a certain environmental and emotional climate during the examination. During the pretest interview, the polygraph examiner will explain your legal rights, explain the polygraph instrument and how it works, discuss the issue, develop and review all questions asked on the polygraph test, cover general background information, and will provide instructions for the actual testing phase.
