People lie as a defense mechanism against avoiding trouble with bosses or the law or any other authority. Lie detector tests and lie detector testing are conducted with the use of instruments that help not so much in detecting lies but in determining - with the help of lie detector software - whether deceptive behavior is on display. The lie detector machines, the polygraph machine, the pocket lie detector, are all devices manufactured for the purpose of monitoring a person’s physiological reactions and to detect behavior that is perceived as untruthful.

Who Uses Lie Detectors

The use of polygraph tests and knowledge of how lie detectors work are limited in the private sector, but often made use of by the US government. The most frequent users of lie detectors like the polygraph machine are usually:

The FBI
The CIA
The Police Departments right through the USA
The State and Federal Governments
Many Private Agencies
In Pre-Employment Screening
Banks
Internal Affairs and Law Enforcement Investigations

The Employee Polygraph Protection Act

The EPPA or the Employee Polygraph Protection Act of 1988 helps in: 1. Preventing employers from subjecting their employees and those in pre-employment screening situations, from taking the lie detector tests - with certain exemptions.
Ensuring that generally employers cannot discriminate against any employee or any job applicant for exercising their rights under the Act, and refusing thereby to take the lie detector test.
Making sure that employer has the EPPA poster displayed prominently in the workplace for his employees.

The Three Basic Approaches to the Lie Detector Test

There are fundamentally three basic approaches to the lie detector test. They include:

The CQT or the Control Question Test

This sort of test compares the suspect’s physiological and biological response to core questions about the crime with his response to key questions about possible prior misdeeds.

The DLT or the Directed Lie Test

This type of test attempts to detect lying or deceptive behavior by comparing the test subject’s biological responses when he is asked to deliberately lie, to those responses when he tells the truth.

The GKT or the Guilty Knowledge Test

This crucial test compares the suspect’s physiological or biological responses to multiple - choice type of questions about the concerned crime, among which one choice alone would contain information that only the suspected criminal and investigators know of.

Do Lie Detectors Speak The Truth?

You must be wondering as to how the polygraph operator, with the help of sophisticated lie detector software (like the pocket lie detector for example), can confidently assert that a suspect is lying. After all, most persons, even the innocent among them, do get stressed out, when faced with questions that could land them in trouble. But the polygraph operator has certain methods that he employs to overcome this problem:

Before asking key questions like “Were you the one who did it?” or “Were you there when it happened?” or “Don’t you personally know what happened?” he first asks a set of questions some of which are designed to cause a measure of emotional discomfort according to the suspect’s personal situation and circumstance, and some of which can be called emotionally neutral in nature.
Then the test subject’s biologic responses to these questions are carefully and painstakingly recorded.
Next, when the operator skillfully gets round to the key questions, the subject’s responses to these core questions can be calibrated, measured and compared to his responses to the control and the neutral questions.

Though analysts are quick to point out the numerous devils in this sort of lie detector accuracy test, varied independent tests have shown an accuracy rating in the 80-90% range.

Continue to: How Lie Detectors Work and Lie Detector Accuracy

Do You Hear Footsteps Around the Corner? Confirm Your Suspicions with a Listening Device
Spy Camera – Get In Touch With The Basics
Fool The Intruders! Make Use of Voice Changers
Eavesdropping - Don't Fall Prey to It!

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