Polygraphing and its application in the Conventional Investigative Process can be a contentious issue. There are many reasons for this, but ultimately, as in all things, the level of input is equivalent to the resultant product.
The bulk of research done over the years, irrespective of personal opinion, is indicative of the fact that properly conducted polygraph examinations produce findings significantly better than chance.
As such, this investigative tool has significant potential in the conventional investigative field.
Where did polygraphing come from?
The detection of lies – and the importance of truth – has long been valued and sought in decision-making processes. Inarguably, with elevated knowledge and insight, we have the ability to make improved decisions, irrespective of circumstance.
In 220 BC, Chinese subjects who were under investigation were made to chew on rice for a period of time, then spit it out. If the chewed rice was hot and lumpy, the subject was deemed truthful. If it came out dry, he was considered deceitful. This simple yet effective physiological response to threat was one of the first known starting points in the pursuit of truth, using means other than the spoken word.
Today, although methodologies and technologies are much improved, the ability of the investigator to reduce the scope of any given pool of potential suspects remains key in any investigative process. This is where professionally administered polygraph testing can be of great value, offering the most accurate means of differentiating truth from lies in the world today.
What is the polygraph?
It is not a “lie detector,” but rather an instrument that is used to measure physiological changes in relation to a stimulus or question. A good comparison may be the use of a thermometer to measure temperature changes.
In this case involuntary physiologically activity, as well as intentional, disruptive physical activity (physical attempts at countermeasures) are recorded and analysed, using various components, which are mostly attached to the subject.
How do I choose my polygraph examiner?
The most critical aspect of the entire examination is the examiner. The following is a list of “musts” which should be complied with, failing which the examiner should not be engaged:
- International accreditation/qualification
- Not exceeding the maximum number of four tests per day
- Proper test durations of 90 minutes per exam
- Willingness to have his/her work reviewed, to confirm outcome and/or quality
- Proper technology, including uninterrupted recordings, of the entire process and anti-countermeasure sensors
Is polygraphing admissible?
The only test in terms of the admissibility of any form of evidence is in terms of its relevance.
It follows that if the evidence gathered during the course of any given polygraph examination, relates to the issue under scrutiny, should therefore be admissible.
This evidence, then, has to be heard and the value thereof tested. To refuse polygraph evidence without reason, could flaw the process (See: Truworths Ltd v CCMA & others (2008) 17 LC 1. 11. 73).
Reported in (Butterworth’s)