How does the procedure of a lie detector test work?

Most of us can conjure up some pretty vivid imagery about exactly what happens during a lie detector test.  Some of it is no doubt fed by movies featuring heavies interrogating either the good guy or the bad guy, and waiting to put the screws on once the results are in.

The truth is that a polygraph, or lie detector, as daunting as it seems to most of us, is a rather ordinary machine that needn’t instil fear in you if you are on the up and up.

Let’s face it though, despite its innocuous appearance, even the most transparent of us would rather not go through the experience of a lie detector test.

Let’s look at what happens during a lie detector test:

At the outset it’s important to note that anyone taking a lie detector test is going to experience a degree of nervousness, but this is not the type of nervousness that will affect the outcome of the test.

The stress responses measured by the lie detector are way above the norm, and are those that are not ordinarily obvious to the naked eye.

The highly sophisticated equipment that makes up the lie detector is rigged to measure physiological responses that we’re generally not able to control, such as:

  • Cardiovascular
  • Perspiration
  • Respiratory response

These are the three stages of a lie detector or polygraph test:

Pre-testing phase

This is an important phase during which the polygraph examiner and the subject will establish a report, a kind of a get to know each other time, which helps to get the subject as relaxed as possible ahead of the test phase.

The subject will be given information about how the lie detector equipment works and given the time to voice any questions they may have about the process.

The reason for the lie detector test will be discussed, so that the subject is able to put forward their version of the situation that has resulted in the necessity for the test.

Questions will be discussed and agreed upon at this stage too.

This is also a chance for the examiner to get a good feel for the subject by observing their body language, speech patterns and responses during this period, which is actually the longest part of the whole test procedure.

The test itself

Without getting into the technicalities of the equipment used (by the time you get this far, you’ll know all about it from the first stage anyway), this is when you’ll be attached to the equipment.

The results collected by the equipment will be sent through to the monitor during the test, the results of which will be discussed in the last stage of the lie detector, or polygraph test as it’s sometimes known.

The final phase

If you’re the one in the hot seat, so to speak, this is when the examiner will analyse all the data collected by the equipment and provide you with the results immediately.  It’s important to note that you’ll be able to sign each sheet reflecting the results to make sure that there’s no chance your results will be confused with anyone else’s test.

King Investigators have an experienced team of polygraph examiners available to carry out professional lie detector tests in South Africa.

As the top private investigators in Pretoria and Johannesburg, you can be absolutely sure that the entire procedure will be carried out with the highest level of integrity and professionalism.

If you’d like in-depth information about the tests carried out by King Investigators, please don’t hesitate to call the team, or chat with them online.