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 (CPS). 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.
The word “polygraph” literally means “many writings”. The name refers to the manner in which selected physiological activities are simultaneously recorded. What we today refer to as a polygraph or lie detector is a scientific instrument, which is capable of simultaneously recording two or more channels of data. This data is the specific physiological changes produced by an individual when he/she is asked questions pertaining to a specific area under investigation. These recordings or graphs which are known as “polygrams” are then interpreted by a polygraph examiner.
The term “polygraph” derives from the Greek words poly (many) and graph (writing) — “many writings”. The name refers to the manner in which selected physiological activities are simultaneously collected, measured and recorded. The polygraph is a scientific diagnostic instrument that is used by a polygraph examiner to administer a polygraph examination for the purpose of verifying the truthfulness of a person’s statement with regard to a specific issue – whether criminal, civil or private – that is the object of an investigation. The polygraph is often called the “lie detector”. An examiner may use an analog polygraph, however, today, most polygraph examinations are administered using digital or computerized polygraph technology.
A polygraph is an analog or computerized instrument that measures selected physiological activities within the body. A polygraph instrument collects data from at least three systems in the human body including respiratory or breathing, blood pressure, and sweat gland activity. Convoluted rubber tubes are placed over the test subject’s chest and abdominal area which record respiratory activity and two small metal plates are attached to the fingers to measure changes in sweat gland activity. A blood pressure cuff, or similar device is used to record cardiovascular or blood pressure activity.
