The 3 basic steps of a professional polygraph test

Most of us can conjure up some pretty vivid imagery about exactly what happens during a lie detector test, in truth though, it is neither as frightening or as threatening as one may believe, provided of course that you’re one of the good guys!

Let’s face it though, even the most innocent of us would rather not go through the experience of a lie detector test. Let’s hope a bit more information will make it less stressful on the innocents!

What happens during a lie detector test?

Feeling nervous ahead of taking a lie detector test is only natural, however, this general kind of nervousness won’t count against you or affect the outcome of the test.

The stress responses measured by the lie detector are beyond the norm, and these stress responses are of a kind that aren’t ordinarily observable to the naked eye.

As a highly sophisticated piece of equipment the lie detector machine is set to measure specific physiological responses that in general we can’t control, such as:

  • Cardiovascular responses
  • Perspiration
  • Respiratory response

Here are three basic stages you can expect during a lie detector or polygraph test:


This is the part where the professional polygraph examiner and his subject will establish a report, where you’ll both of a get to know each other a little more before the test begins, which really helps to get you as relaxed as possible ahead of the real test phase.

You’ll be given information about how the lie detector equipment works and time to raise your own questions about what the process entails.

Obviously this is when the reasons behind the need for the lie detector test will be discussed, so that you’ll be able to share your version of the events that have led up to the necessity for the test.

As a professional, the polygraph examiner will also use this as an opportunity to get a good read on the subject prior to the test, observing body language, speech patterns and responses during this period. This is generally the longest part of the procedure.

The actual test

Once the preliminaries are over, you will be attached to the polygraph machine, at which time you’ll already be feeling a bit more comfortable about it all.

During the test, the results of the responses to questions will be sent through to the monitor, all of which will be discussed at the end of the polygraph test.

The last stage

The examiner will be able to examine the data collected by the equipment during the test in order to provide you with the results immediately.  It’s a good idea at this point to sign each sheet of the results so that you can be certain that your results won’t be confused with anyone else’s test.

As experienced polygraph examiners, King Investigators has a team of investigators available to carry out trusted lie detector tests anywhere in South Africa, at the drop of a hat.

As the top private investigators in Pretoria and Johannesburg, you may rest assured that the entire procedure will be carried out with the highest level of integrity and professionalism by this team.

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

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