Editorial: ‘Lie detectors’ put under a microscope

Thursday, Oct. 10, 2002 | 8:32 a.m.

Polygraph machines, called "lie detectors" by their supporters, have been touted for ferreting out murderers, spies and other dangerous criminals. Of course, what backers of polygraphs don't like to note is that they're really not lie detectors at all. People who are in fact guilty have been known to use relaxation techniques to "beat" the polygraph machines, which are supposed to be able to detect lying by measuring someone's heartbeat, blood pressure and other factors. By the same token, someone who is just plain nervous can be wrongly cast by a polygraph machine as lying when they're actually telling the truth.

In view of all the limitations of polygraph machines, it was encouraging to see that the National Research Council recently concluded in a study that polygraph machines aren't reliable enough to determine if government employees pose security risks. The research council, part of the National Academy of Sciences, noted that overconfidence in polygraph machines could result in agencies failing to use other types of security reviews more often. We believe the federal government should stop its over-reliance on a machine that really is nothing more than a nervousness detector.

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