Between Showers

Lie To Me’s Take on the Hand-held Lie Detector

The 2nd episode of the new Fox television series, Lie To Me, opened with a quick debunking of the polygraph. Cal Lightman, the shows main character, is a behavioral scientist who specializes in the study of facial expressions. Asked by the Department of Homeland Security to evaluate its new hand-held polygraph, he graphically illustrates how it is no better than a primitive trial by ordeal in which a person accused of a crime must hold an egg without breaking it.

It’s worth noting that the questions identified in the segment as “control” questions (“Do you work for the Department of Homeland Security?” and “Do you have black hair?”) are actually _irrelevant_ questions and would not be scored.

Unfortunately, the hand-held lie detector seen in this episode is not something made up by Lie To Me’s screenwriters. In 2008, the U.S. Department of Defense began fielding just such a hand-held polygraph in an attempt to screen out terrorists among the local populations in Afghanistan and Iraq. For more on the “Preliminary Credibility Assessment Screening System” (PCASS), see:

https://antipolygraph.org/cgi-bin/for…

and for information on how this scientifically baseless “test” can be passed whether or not one is telling the truth, see:

https://antipolygraph.org/cgi-bin/for…

For more on Lie To Me, see:

http://www.fox.com/lietome/

For more on the work of Paul Eckman that inspired the show, see: