Polygraph Testing

What is a Polygraph Test?

A polygraph is a scientific way to determine deception or truth regarding any specific incident or general honesty.  It is a powerful tool to utilize during an investigation process and to determine honesty within the working environment.
How does the polygraph work?
The working of the polygraph is based on the recording and interpretation of psycho physiological changes in the body when someone is answering particular questions. These changes are the result of messages received through the autonomic nervous system. "Autonomic" means automatic or involuntary, so it deals with those aspects of the body that cannot be controlled voluntarily. It is helpful in the detection of deception because the individual being examined is unable to control these reactions in the body.
There are two branches to the autonomic nervous system. The first one has to do with growth and development, and the second one is an emergency system. The emergency system becomes dominant only when there is some threat to an individual and he or she becomes fearful, stressed or deceptive.  When that happens, a series of physiological changes occur, such as: the heart contracts more quickly and strongly, which sends more blood throughout the body, breathing increases as so does perspiration.
The polygraph instrument records these physiological responses through four sensors. If you tell the truth, you will function at your normal physiological level. If you are asked a question to which you are going to lie, your brain will register a threat because you do not want to be caught in a lie. As soon as your brain registers the threat, your body automatically shifts into the emergency system. These are involuntary responses and can not be controlled, as opposed to spoken words.
The Polygraph records physiological responses and the polygraphist interprets the changes that occur in response to various questions. As the individual does not have control over physiological responses, the recording of these changes in the body, by the polygraph, remains one of the most effective methods of establishing truthfulness.
Procedures followed during an examination
A typical polygraph examination will include periods referred to as a pre-test phase, a chart collection phase, post-test phase and a test analysis phase. This procedure usually takes one to one and a half hours.
·         In the pre-test phase, the polygraph examiner will complete required paperwork and explain the theory of the polygraph in an understandable way to the examinee. The examinee will be given the opportunity to discuss their roles or perceptions regarding the case under investigation and provide relevant information. During this period, the examiner will discuss the questions to be asked and familiarise the examinee with the testing procedure.
·         During the chart collection phase, the examiner will administer the examination and collect a number of polygraph charts. No questions will be asked during the examination that have not been discussed and reviewed with the examinee.
·         In the post-test phase, the examiner will analyse the charts and render an opinion as to the truthfulness of the person taking the test. The examiner, when appropriate, will offer the examinee an opportunity to explain physiological responses in relation to any questions asked during the examination.
Frequently asked questions
Is there any law controlling use of polygraph in South Africa?
Polygraph Testing is a fairly new concept in South Africa, especially in disputes relating to employment relationships.  There is no legislation at this point to control the use of the test or to protect the employee’s right against the abuse of the test. Polygraph results are not admissible in a criminal court.
Can one be compelled to undergo a Polygraph Test?
It is against the Constitution of South Africa to compel a person to undergo a Polygraph examination, unless she or he consents to it.  The consent must be in writing.
The individual should be informed that –
  • The examinations are voluntary;
  • Only questions discussed prior to the examination will be used;
  • He/ she has a right to have an interpreter, if necessary;
  • Should he/she prefer, another person may be present during the examination, provided that person does not interfere in any way with the proceedings;
  • No abuse, in whatever way, will be allowed;
  • No discrimination with be allowed;
  • No threats will be allowed.
When is the employer permitted to use Polygraph?
Generally, employers are permitted to use the polygraph to investigate specific incidents where –
  • Employees had access to the property which is the subject of the investigation;
  • There is a reasonable suspicion that the employee was involved in the incident;
  • There has been economic loss or injury to the employer’s business like theft of property;
  • The employer is combating dishonesty in positions of trust;
  • The employer is combating serious alcohol, illegal drugs or narcotics abuse and fraudulent behaviour within the company;
  • The employer is combating deliberate falsification of documents and lies regarding true identity of the people involved.
Who gets the Polygraph results?
Polygraph results cannot be released to any person but to an authorised person.
Generally it is the person who has undergone the Polygraph Test (examinee), or anyone specifically designated in writing by the examinee, firm, corporation or government agency that requested the examination.
What is the status of the Polygraph Test at the CCMA?
Polygraphists have been accepted as expert witnesses whose evidence needs to be tested for reliability.  The duty of the Commissioner is to determine the admissibility and reliability of the evidence.
Polygraph Tests may not be interpreted as implying guilt but may be regarded as an aggravating factor especially where there is other evidence of misconduct.  In other words, Polygraph Test results, on their own, are not a basis for a finding or guilt.  It can be used only in support of other evidence.
It is advisable to use a Polygraphist that is registered with an organisation such as PASA (Polygraph Association of South Africa) and to ensure that they will be willing and available to testify at a CCMA hearing. You will be able to find a registered Polygraphist on the PASA website at www.pasa.co.za
Extracts taken from the PASA website and CCMA website.
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