A lie detector is also called a polygraph and it measures and then records a number of physiological indices like respiration, skin conductivity, pulse and blood pressure when one is asked some series of questions. The lie detector usually records different changes in the physiological makeup as one answer the questions. The examination is a blend of an interview and psychological testing technique.

Who should take a polygraph test?

Sometimes people want to take a lie detector test because they want to confirm their own innocence or the innocence of someone else. When you submit to such a test, do not take it lightly as it can actually alter life. You should understand why anyone wants to take such a test and be aware that the outcome can affect you positively or negatively. You need to take it voluntarily.

Is a lie detector test reliable?

The polygraph is actually highly reliable but that depends on whether the examiner carrying out the test is well trained and using the latest computerised equipment and validated techniques. There are lots of studies carried out regarding the reliability of these kinds of tests and it has proven that the examiners that are qualified have an accuracy rate of 98% in the conclusions that they make.

What should one expect during the test?

Usually, a lie detector test can take at least one and a half hours, but it can be up to four hours. The duration depends on what is being tested. The test has different sections.

You start with a pre-test interview. This is where you give consent for the conduct of the test. The equipment that will be used is then explained and some background information obtained from the examinee. The examiner then discusses the questions and then familiarise the examinee with the procedure that will be used.
Data collection is the second part of the polygraph. Here, the components are attached to the examinee. Here, you have the sensors to the chest and a blood pressure cuff at the upper arm. This helps in recording the pulse and heart rate. One also gets the electro dermal cuffs attached to 2 fingers aimed at measuring the skin conductance. The examinee also has to sit on a mat used to sense movement. The last phase is analysing of results and getting an opinion about the results.

Is it possible to fail a lie detector test because you are nervous?

It is quite possible to be nervous just before one gets the test. However, it cannot lead to failure of the test. The only thing that affects you is if you tell lies. You may be innocent but feel nervous. The reactions of nervousness that appear on the charts are not the same as the reactions recorded because of lying.

Can one beat the test?

It always happens in the movies, right? However, when one uses the latest equipment’s and techniques, this is rather improbable. The polygraph is used to record the autonomic reaction of a person as he/she answers the questions. If you try to distort the tracings, a trained examiner can tell. A qualified examiner can spot anyone trying to alter the test outcome and may decide to abandon the test altogether.

How much does the test cost?

The charges depend on the test provider. There are different modes of payment that may be given to make payment easy. Sometimes, a deposit may be requested when one books a test.

Where can you get the tests done?

The tests need to be conducted in an environment that is free from all distractions. There is also a need to have some two chairs and a table. Usually, the lie detector test can be done at the examiner’s office or at home if that is what you want but at an extra cost.

How should one choose a lie detector examiner?

For an examiner to be qualified, he needs to be trained professionally and then graduated from a polygraph school that is well accredited in the area of operation. In some areas, one has to be approved by some associations within the polygraph industry. The examiner needs to have computerised equipment that is up to date and all the techniques that have been validated. Since many changes have been effected, the examiner should keep track of them at all times

Is it legal for someone under the age of 18 to take the test?

Yes. As long as there is a written consent from the guardian or parent of the person in question. However, people below 14 years may not be tested.

What are the possible questions that may be asked?

Usually, the questions are formulated together with the client so as to ensure that the test issue is covered and also meet the rules that are required within the latest techniques. The examiner advises on the questions that may be asked to ensure the issue being tested for is covered.