Lie Detection Tests 101- Top Facts You Need To Know

Lie detection tests, in a layman’s term, are tests that work to figure whether a person is lying or not in answer to certain questions. A special machine, polygraph, is used to gauge the responses given by the subjects on questions asked by trained lie detection professionals. Lie detector tests are most commonly used on alleged criminals, especially sex offenders. However, these days some employers too take to lie detector test while screening potential employees. The post below offers a brief on the most crucial aspects of lie detection test.

What is it and how does it work?

Also known as “polygraph test”, a lie detection test is meant to analyze the physiological reactions of the subject in response to certain possible lie-control questions. The purpose of the test is to figure out whether the person being questioned is being honest with the answers pr not. The physiological responses gauged here include the subject’s blood pressure, breathing, perspiration and heart rate.

As part of the test, the subject would be connected to the polygraph. Now, the polygraph official will ask his questions and as the person answers, the polygraph will record his physiological responses. The polygraph officials will observe the polygraph monitor to study the physiological responses and pass his verdict based on those readings.

However, before the actual polygraph test, a polygraph official usually conducts a pre-test session with the subject. It is done to serve two purposes. One, to glean some basic preliminary data about the subject that would be utilized to frame the main diagnostic questions later. The other one is to explain the entire concept of polygraph test to the subject.

Types of questions

It’s to note here the subject will be asked three sets of questions- relevant, irrelevant as well as control questions.

The irrelevant ones are those that generate obvious answers. The relevant ones are those bear direct relation with the particular reason behind polygraph. The control questions are those which could be indirectly related to the specific reason behind your lie detection test and might refer to your past deeds. Responses received from control questions will compared with those received from relevant questions.

What decides pass or fail?

If the reactions of the subject are greater with control questions, the subject will be considered to have passed the test. But, if the reactions to relevant questions are greater, you will fail the test.

How long does it take?

A standard lie detection test will take around 1-3 hours to complete. The whole process will cover medical history and background assessment of the subject, explanation of test, the main polygraph as well as follow-up.

Cases where lie detection tests are used:

  • Legal investigation

Lie detection tests are sometimes used in criminal trials as an additional source to determine the credibility of a witness. Polygraph tests can also be a part of civil lawsuit probes. However, nobody can force a person to sit for lie-detection test. A subject has every right to refuse a polygraph test of s/he doesn’t want to take part in the test. However, the regulation regarding polygraph testing isn’t very lenient when it comes to sex offenders. In fact, in certain States, it’s now mandatory for these offenders to sit for the test prior to consideration for probation or parole. Sometimes, lie-detection tests are implemented to monitor and keep track on sex offenders.

  • Homeland Security cases

The FBI, the CIA, the NSA as well as other federal law-enforcement bodies responsible for national security use lie-detection tests on suspected individuals.

  • Investigations related to commercial theft

Businesses suspecting employee theft and fraud might conduct polygraph test to check employee loyalty and honesty. It’s especially relevant for businesses that deal with financial assets such as banks.

Is the test accurate?

Now, the accuracy of lie detection test is moot point and there have been long debates on its efficacy. There is no concrete evidence that the data gathered from lie-detection tests are always 100% accurate. In fact, certain medical conditions and consumption of drugs might badly affect a lie-detection test, usually leading to inconclusive results. However, the test is still routinely carried on in investigations and pre-employment screening procedures these days.

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