Ethical Use of Lie Detectors

The polygraph often leads to the innocent being accused of lying.

The lie detector test, also known as a polygraph, looks for physical reactions to emotional stimulus, such as an increase in blood pressure, to determine if a person tells a lie.

Function

Lie detector tests that look for physiological responses are consistent, but not necessarily accurate. The National Academy of Sciences estimated that a lie detector test could catch eight of ten spies working for a government with 10,000 employees, but would also "catch" 1,598 honest people. Lowering the sensitivity would only accuse 41 innocent people, but let eight of the ten actual spies go free.

Considerations

Some lie detectors use a voice analyzer to look for stress in a person's responses. This type of test could be used on people who do not agree to undergo an analysis, such as those who give recorded speeches.

Employment

In the U.S., lie detector tests are, in general, only used during criminal investigations and by employers whose workers handle sensitive information. Some other countries, such as the United Kingdom, allow employers to test any job applicant who agrees to take the polygraph exam. However, the Aston Business School's Dr. Steve Woods believes that polygraphs are useless for determining whether someone will become a good employee.

Features

Lie detector tests rely on a person reacting to information that only the criminal and the investigators know. However, the person administering the polygraph might only have one or two pieces of information to go on--not enough to make an accurate estimation of a person's guilt. Due to the questionable nature of polygraphs, the test results are generally inadmissable as evidence in court.

Potential

A new type of lie detector test uses sound waves to remotely detect lies. This poses new ethical questions because one can use it in real time without a person's consent. Also, this test looks for changes in sweat glands, which could lead to a false-positive if someone is nervous about something else.

References

• Skeptic's Dictionary: Polygraph
• University of Colorado-Denver: The Polygraph
• Jishka: The Lie Detector - Does It Really Work?; Gershaw, David

Resources

• BBC News: Employer lie detector use 'grows'
• ABC Science: Remote lie detection raises ethical issues