Are you going to tell the truth today?

POLOKWANE – Lizette Snyman, a lie detection expert is an internationally accredited polygrapher.

This means she is contracted by companies to perform lie detection tests.

(video) Nothing but the truth: a step-by-step polygraph test

Snyman received her training as a forensic psycho-physiologist (polygraph examiner) from the Academy for Scientific Investigative Training, based in Philadelphia, US. She has gained a wide knowledge of the retail and logistics environment, forensic investigations and disciplinary procedures over the years and through numerous studies at various tertiary institutions: PCE, Wits University, Unisa, JD Learning Academy and Academy for Scientific Investigative Training (Philadelphia, US) and attended advanced courses offered by AIIP in the US.

Snyman also completed a course in the forensic analysis of statements (Scan). She testifies as expert witness at CCMA level on behalf of her clients upon her clients’ requests. “You cannot fail a polygraph test because you are nervous. We do a pre-test where we ask the person to lie just to see how his levels react. I work all over Limpopo and Mpumalanga and travel a lot. I have an interpreter for African languages.”

She says there are three types of tests, the pre-employment test, background screen specific test and the periodicals that take place once every few months.

“It is very difficult to test young children. Secondary school children are better. I test anyone from domestic workers to suspected child molesters. There are three types of questions, the irrelevant questions like your name, the control questions and then the relevant questions; these are the questions that will show if you are guilty or not. Before a test I always do a forensic assessment. I also advise the examinees they cannot be forced to submit to take the polygraph examination for any reason and it is voluntarily. With full knowledge of their rights and without duress, coercion, force, intimidation or promises of immunity or reward, they agree and give consent for the examination to be conducted for the mutual benefit of their company and themselves. In the consent, they also authorise the examiner to disclose all information, results, conclusions and opinions from the said interview and examinations to the polygraph examiner’s client, for whatever uses they may determine.”

Snyman explained the procedure and questions so nothing comes as a surprise for the examinee. She said the forensic assessment interview takes long and during this time she reads the person’s body language.

“We start by ‘walking the crime’ as we call it. That means the matter under investigation was discussed with them and was combined in the relevant questions. If there are questions the person does not understand, I explain them. The polygraph machine is a computerised polygraph system. It simultaneously records thoracic and abdominal breathing, electro-dermal activity and relative changes in pulse rate, pulse amplitude and blood volume.

“The examinations are conducted in the prescribed manner as stipulated by the Code of Conduct of Internationally Accepted Standards. The polygraph is a set of instruments attached to the body and handled by a qualified practitioner and certified forensic psycho-physiologist. The polygraph has the ability to determine whether a person has been truthful and whether they have disclosed all they know or suspect about a matter. The results of a polygraph examination are admissible in most labour tribunals, including the CCMA, and to a limited extent, in criminal matters where an examinee has confessed to a crime.”

Snyman said sometimes it happens the examinee confesses before the start of the test. “Before a test, I tell the story of a snake and how your heartbeat speeds up if you see a snake, to explain to the examinee what will happen if he lies.”

Snyman’s company is called Limpopo Polygraphs CC.