History of Polygraph Testing
Polygraph testing goes back a long way, for centuries in fact, from primitive ways and means.Over the years, the polygraph instrument and the testing techniques revolutionised, underwent many changes, in particular technological changes culminating into the modern computerised
instruments that are used today locally and internationally. According to research documents, the first portable polygraph instrument was developed by a John Larson in 1921. In South Africa and in fact around the world, polygraph testing is inter alia used for various applications in large organisations, medium to small enterprises as well as in the private sector. Larson chose the name Polygraph from Greek “many writings” as it could read and record multiple psychological responses The word Polygraph is also from Latin where poly meaning “many” – the number of sensors attached to the body sends multiple (“poly”) signals to the instrument which is recorded (“graph”)

What is a polygraph examination?

• A polygraph examination, often colloquially (commonly) referred to as a lie detecting test, is a three-part process where a computerised polygraph instrument is used to record select physiological activities of i.e. stress, breathing rate, skin conductivity activities, blood pressure, heart rate and blood pulse volume – depending on the amount and type of sensors used and placed on the examinee’s (person tested) body.      
• The different parts are commonly referred to as a Pre-test interview phase, the In-test phase and the Post-test-interview phase:

The Pre-test interview phase:

• Proper introductions are done and during this process the polygraph examiner puts the examinee at ease as much as possible, building rapport, and also ascertain whether an interpreter may be needed if the examinee was not comfortable that the entire polygraph examination would be conducted in English – the primary language used during the entire polygraph examination.
• The examinee is informed that the polygraph examination is a voluntarily process and that that the entire examination would be recorded using both audio and video.
• In terms of the framework of South African legislation including the POPI Act, the examinee also voluntarily signs a consent form to undergo a polygraph examination and to provide associated personal information.
• The examiner assesses the suitability of the examinee to be tested and continues with the process when it appears that the examinee is suitable.
• The examiner explains the test procedures including the function of the polygraph instrument and its sensors and how the examiner uses the polygraph recordings, also known as charts, to arrive at conclusions concerning the truthfulness of the examinee tested.
• An in depth discussion regarding the issue under investigation is accomplished.
• All the test questions that will be asked during the In-test phase of the polygraph examination are then reviewed with the examinee.

The In-test phase:

• The examinee is seated in a chair and all the various sensors are attached to the body of the examinee – the examinee remains fully clothed during the entire polygraph examination.
• The questions previously reviewed are asked while the polygraph instrument is constantly recording the select physiological activity.
• An acquaintance test to familiarise the examinee with the testing process and to permit the examiner to identify any problems associated with the examinee’s understanding of the process or with the data collection can be detected during this initial in-test phase.
• The acquaintance test is normally administered as the first test (chart). The examiner also uses the acquaintance test to conduct functionality checks to confirm that the instrument was in proper working order.
• The acquaintance test is considered a mandatory part of the polygraph examination process.
• A series of tests (charts) are administered during which the same questions are asked during each tests (charts).
• The minimum number and type of tests (charts) is determined by the specific type of polygraph technique being applied. In most polygraph techniques, the questions are asked at least three times by conducting three tests (charts). All test is of relatively short duration so determined by the number of questions asked during every tests (charts).
• The sequencing of the questions during each tests (charts) is determined by the specific technique being applied.

The Post-test interview phase:

• The examiner evaluates the polygraph test in an effort to determine the truthfulness of the examinee
• When possible and appropriate, the examination results are discussed with the examinee to afford the examinee an opportunity to explain noted significant reactions to relevant questions or any negative finding or to answer any examiner questions. Also to reveal any further information that could assist with the investigation/polygraph examination.