Dear Editor,

Minister Dwight Nelson’s faith in polygraph tests is no doubt well meant. However, his faith seems ill-placed, as scientists have largely discredited polygraphy. Given scarcity of resources, it is important to spend tax dollars on the kinds of forensic tests that are credible.

Lie detector tests are supposed to identify emotions. Rates of breathing, sweating, and beating of the heart are expected to show whether persons such as policemen or senior civil servants are telling the truth.

Because these tests can be defeated or proved wrong, scientists consider them neither valid nor reliable. For example, someone who is nervous or fearful of the polygraph test may have increased breathing and heartbeat rates. However, a chronic liar may maintain stable breathing and heartbeat no matter the size of his lie. In addition, the examiner’s interpretation of the data is subjective. For those who might want to beat the system, internet research shows ways of outsmarting lie detector tests.

Security personnel in the USA tend to rely on polygraphy. However, a former director said, “(The CIA’s) reliance on the polygraph is truly insane.” An FBI special agent said, “Whether it is screening applicants or screening employees, the polygraph is a failure. I suspect that its days as a screening tool are deservedly near an end.” From 1945 to the present, at least six Americans had been committing espionage while they successfully passed polygraph tests.

According to findings of a 2003 report from the US National Academy of Sciences, the majority of polygraph research was “unreliable, unscientific and biased”. The research showed that the level of accuracy was particularly low when polygraphs were used to screen the police or civil servants.

Legal opinions do not support the use of polygraph tests. In 1998, a majority of United States Supreme Court judges stated, “There is simply no consensus that polygraph evidence is reliable.” Polygraph tests are generally inadmissible in courts all over the world.

Use of polygraphy may lower morale when the innocent lose their careers and reputations to tests known to be inaccurate and unscientific. On the other hand, these tests may open doors for the corrupt who are skilled at beating any system.

Perhaps there is still room for tax dollars to be invested in scientific methods with track records of success.

Yvonne McCalla Sobers

sobersy@yahoo.com