Plumstead resident Thomas Kent spends most of his working life searching for the truth.
Mr Kent, 45, is a professional polygraph examiner and chairperson of the Cape Association of Polygraph Examiners.
He owns a polygraph-testing business and says he knows of approximately 40 working polygraph examiners in Cape Town.
A polygraph test is used to determine whether one has been deceptive or not.
The psychophysiological test is conducted by an accredited polygraph examiner, explains Mr Kent.
The person being tested is attached to a polygraph machine and asked a series of yes or no questions.
Their biological reactions are then reflected on a chart that the examiner uses to present a report and determine a result.
The accuracy of a polygraph is not 100%, however, the subject needs to score between 90% to 100% for both a pass or fail for the test to be valid. This is an international standard based on research conducted by the American Polygraph Association.
The process is clearly explained to the person being tested before it starts.
A consent form is signed and the test has to be conducted fairly and accurately. There is also a practice test taken before the real one begins.
The frame of mind of the subject is also taken into consideration, such as whether they are fit to take the test.
Mr Kent says that people often do not realise how much of a great investigative tool a polygraph can be. It can help in resolving conflict, especially in the working world.
The majority of his business comes from working with companies who seek to do polygraphs on their employees. This has become common and has led to the increasing demand of polygraph examiners in South Africa.
Other things that polygraph examiners get commissioned for are infidelity cases when one wants to know if their spouse has been cheating, or child molestation cases, which are more rare.
When working with companies, there are pre-employment tests to screen candidates.
Testing is voluntary by law and no one can be forced to do it, however, employees are often bound contractually to perform the test.
“It’s a good day if you can resolve the problem without the test. If there’s admission or a confession, then I withdraw,” said Mr Kent.
He said he would like the fearful perception of polygraph examiners to change.
“We’re not there to take away work from anybody. We’re there to mediate. We cannot enforce anything. We need permission from the client to take on the work.”
He said that it is unlikely for an employee to lose their job only because of a polygraph, as a polygraph should support other evidence presented. Polygraph examiners are also sometimes called into the Commission for Conciliation, Mediation and Arbitration (CCMA) to present their evidence based on the tests conducted.
To qualify, Mr Kent said he attended a 13-week course in Johannesburg in 2008 where one has to pass by 85% or above and complete 400 hours of practical work.
The course covers the history of the polygraph, psychophysiology, ethics and forensics, pre-testing procedures, question formulation, scenarios, interpreting and evaluating a chart, law on polygraph, labour law practices, post testing procedures, counter measures, and writing up reports.
Mr Kent graduated first in his class, obtaining a Diploma in Psychophysiological Detection of Deception with the American International Institute of Polygraph.
To do the course, Mr Kent said that factors such as maturity level are considered. One also has to have no criminal record, be above the age of 21 and have a good moral standing.
Advanced training is also provided annually by the regulatory American Polygraph Association to teach examiners about new developments in polygraph testing.