Letter to the Editor, Globe & Mail, August 28, 1996

By Russell Wodell

Your headline story “[General] Boyle passed lie detector test” unfortunately revives the highly lucrative mythology surrounded the use of polygraph testing. Despite the ludicrous claims of polygraph operators (such as the 90 percent accuracy rate attributed in the article to independent security consultant Gary Estabrooks), these devices cannot indicate truth or falsehood. All they can measure are various physiological changes indicating stress—usually the stress caused by subjecting a person to polygraph testing. Opponents of polygraph testing counter assert that the tests can be rendered meaningless by means as simple as biting one’s tongue before answering any question.

The results of polygraph testing must be interpreted by the polygraph examiner, much as the entrails of sacrificial animals used to be examined as omens by priests and soothsayers. Like priests and soothsayers, polygraph examines assert a high level of accuracy; scientific analysis invariably reveals that these tests are only as accurate as chance.

Legally and morally, the danger of employing such pseudo-scientific methods is that the results almost always reflect the unconscious biases of the examiners. Their use thus really amounts to an indirect method of intimidation.

Given that polygraphs really only measure stress, and given that military training is designed to enable soldiers to handle extraordinarily stressful situations, it would be rather disappointing if a high-ranking military official could not pass a polygraph test with ease.