The Lie Detector: Why is it Used?

It is based on junk science, is not accurate and is dangerous, but there are several reasons why the lie detector or polygraph test is still used. Here are four of them.

1. It scares people. The test is valued by governments and others because it is useful for getting damaging admissions from people. This is especially true in the usual cases where the subject doesn't know that the test is a sham. In other words, for many who use the test, it is used to intimidate. It is essentially an interrogation tool.

2. There is nothing better. Many are reluctant to give up the only machine they have for detecting lies, even if it doesn't work very well. Perhaps some companies would even find it acceptable to wrongly fire a hundred loyal employees based on failed polygraph tests - as long as they also got rid of the one who was stealing from them.

3. Examiners and examinees are ignorant. Probably most examiners believe that the polygraph is an effective lie-detecting tool. Certainly the industry that produces them doesn't have an incentive to educate them about the flaws of the test, and the lack of scientific evidence for it. Examiners aren't looking for a reason to quit their lucrative profession. And members of the public, in their ignorance, tolerate a test that they think can prove their innocence.

4. Appearances. It is important for government agencies to provide the appearance of security. The public wants to feel that they have some way of catching spies, terrorists and regular criminals. A belief in the lie detector or polygraph test provides this pretense.

The US is, so far as I know, the only nation which places such extensive reliance on the polygraph....It has gotten us into a lot of trouble. - Convicted spy (double-agent) Aldrich Ames, who passed two polygraph tests while spying for the Soviet Union.

Continues here... Polygraph Testing 101

Beat a Lie Detector Test | The Lie Detector: Why is it Used?