Polygraph testing is very much like psychological examinations. A polygraph exam is conducted using a series of tests which are designed to evaluate the truthfulness and deception or fallacies in various situations and aspects.
Companies may use it to screen job candidates but more commonly, it is used to investigate criminal incidents. This kind of examination uses different polygraph tests and questioning techniques which we will learn in this article.
Types of Polygraph Questioning
The major tool of any polygraph examination is the measure of a person’s responses to a set of questions. The various polygraph techniques or tests differ in the way the questions are structured. In polygraph testing, there are basically four types of questions used. In one examination, only one or two kinds of question are used as well as the type of questioning technique.
The different kinds of questions used in polygraph examination are relevant questions, control questions, irrelevant questions, and concealed information questions.
Relevant questions are questions pertaining to the topic under investigation. They can be general in structure and specific at the same time. An example of a relevant question is “Did you steal $500 from your office?” The responses of the subject from the relevant questions have a great impact on the investigation and are of great interest to the examiners.
Control and irrelevant questions are the opposite of relevant questions with a purpose of making comparisons. Control questions can be compared to the relevant question asked. Based from the question “Did you steal $500 from your office?” a control question for this would be “Have you ever stolen anything in your life?” Responses to control questions can affect and create physiological responses to relevant questions.
Irrelevant questions are questions which create no impact and no relation to the focus of the investigation. It is only meant to get the subject ready for the questioning procedure. An example could be “What day is it today?”
The last type of question used in polygraph testing is the concealed information questions. It aims to elicit information and details about the crime that only a guilty subject would exhibit such as the crime scene and the means of committing the crime. The questions are hypothesized in a way that will make guilty suspects reveal a different response from their answers to the relevant questions.
Various Polygraph Questioning Techniques
There are three basic types of polygraph questioning techniques that combine the four types of questions mentioned above. These are relevant/irrelevant technique, control question technique, and the concealed information technique.
The relevant/irrelevant (R/I) technique is generally used during employment hiring interviews. The premise underlying this test is that a deceptive subject has an obviously different reaction or response to the relevant questions than if irrelevant questions are asked. An innocent subject has the same kind of reaction to both types of questions.
The control question (CQT) technique is the most widely used technique in criminal investigations. The technique is to make non-deceptive subjects to reflect on the truthfulness of their answers. Control questions can trace back past experiences which arouse the subject to be doubtful of the sincerity of the answers.
The third technique, concealed information test, is based on a different principle than the first two tests. The test is designed to distinguish a guilty person through the information based on the crime. There are two primary types of concealed information technique. The first one is the peak-of-tension test and the other one is the guilty knowledge test.
The peak-of-tension technique (POT) is composed of five to nine closed questions that are closely similar in structure. The guilty knowledge test (GKT) is about the same as the POT but uses more of open ended questions or multiple choice type.
What is Polygraph Testing used for?
It was mentioned in the earlier paragraph that polygraph examinations are useful in many situations. It could serve as a tool in conducting job interviews or used in crime investigations. The ultimate goal of this kind of testing is to identify any deception or evidence of veracity of information. In the part of private employers, the company is able to screen potential job candidates well. Crime justice investigations have found polygraph testing very helpful in identifying the crime suspect easily and relieving innocent individuals of the investigation.