Shedding Light on Lie Detectors

From MSNBC.com: An extensive study from the National Academy of Science published in 2003 concluded that in a very controlled setting — say, with college students in a psychology lab — a polygraph can discriminate lying at “rates above chance.”

But the machine — which measures pulse, blood pressure, sweat and other physiological parameters — often fails in the real world. Countermeasures, or ways to cheat the test, are well known and widely available. That's why the National Academy of Sciences concluded that “polygraph test accuracy may be degraded by countermeasures, particularly when used by major security threats who have a strong incentive and sufficient resources to use them effectively.”

The Academy found that reliance on polygraph testing to screen government employees who may be potential security threats results in “too many loyal employees falsely judged deceptive and too many security threats left undetected.” Rest of Article. . . [Mark Godsey]