Reevaluating the Lie Detector Test
Bromley, Anne, Developments in Mental Health Law
A woman applies for a job with a county police department and is told she must take a polygraph test to be considered. During the testing she is asked the following questions: Have you ever had an affair? Have you ever participated in an orgy? Have you ever had sex with a dog? We know everyone has sexual fantasies, what are yours?
Sound far-fetched? This happened in Prince William County, Virginia, last year. The Virginia Polygraph Examiners Advisory Board is now investigating the woman's complaint along with seven others that are similar.
Although new regulations were added to those existing for polygraph examiners by the Virginia Department of Commerce, effective September 1, 1988, state and local government agencies remain exempt from the prohibition of asking questions about sex. This exception may prove to be an unfortunate defect in what are otherwise thorough and sound guidelines.
These events have taken place after a long Congressional battle was won to limit the use of the polygraph and a new law passed just this summer. Although this will eliminate almost all preemployment and routine tests by private employers, government agencies and security and drug-related industries remain exempt as long as they do not violate state laws.
This recent legislation may cause one to ask how the polygraph works and why it is so controversial that lawmakers have restricted the conditions under which it can be used.
The polygraph: does it work?
Although its results can be innocuous or devastating, the polygraph simply measures physiological reactions which are supposed to indicate deception to an examiner. The polygraph instrument doesn't actually reveal whether someone is lying or telling the truth. There are no known physiological reactions unique to lying, although societies through the ages have tried various physical tests to prove the truth. For instance, "the Bedouins of Arabia passed a heated blade across the tongue of a suspected liar. If innocent, he would be salivating normally and his tongue would be unburned; if lying, his tongue would be scorched." (1)
The rate and depth of respiration, cardiovascular activity, and galvanic skin response (or perspiration of the fingertips), which are measured by the polygraph instrument, can be attributed to anxiety, anger, fear or humiliation as well as deception. A recent report from the Office of Technological Assessment (OTA) observes that just "being required to take a polygraph test elicits precisely these feelings in many people." (2)
Researchers in the fields of psychiatry and psychology recognize that some types of lying are part of normal development, but the phenomenon is not well understood. Guilty psychopaths or antisocial subjects may escape detection, while innocent neurotics or psychotics will more often be identified as deceptive. The polygraph in particular has not been studied extensively by many psychologists. In 1984, psychologist Benjamin Kleinmuntz declared that "psychology is giving away a socially important tool by default." (3)
The American Psychological Association testified last spring before the House of Representatives that there is no scientific basis for using polygraph testing to screen job applicants, finding the high rate of false positives, where innocent people can be found deceptive, unacceptable. Psychologist Edward Katkin told a subcommittee of the Education and Labor Committee that the polygraph test does not conform to APA's standards, citing poor training of examiners as one reason.
In their 1983 report, "Scientific Validity of Polygraph Testing," the OTA concluded that
there is some evidence for the validity of polygraph testing as an adjunct to typical criminal investigations of specific incidents, and more limited evidence when such investigations extend to incidents of unauthorized disclosure. However, there is very little research or scientific evidence to establish polygraph testing validity in large-scale screening as part of unauthorized disclosure investigations, or in personnel security screening situations, whether they be preemployment, preclearance, periodic or aperiodic, random, or 'dragnet. …