Chicago lawyer William Scott Stewart wrote an article published in the November 1941 issue of Esquire Magazine titled “How to Beat the Lie Detector.” This is probably the first article of its kind focusing on countermeasures against the polygraph, and Stewart pointed out that you could manipulate the polygraph’s results by intensifying your emotions when asked harmless questions. Such “control questions” are asked during the Control Question Test (CQT) and are designed as comparisons to the relevant questions. As for physical countermeasures, Stewart suggested biting the tongue or inside of the mouth or making muscle movements that cannot be seen by the operator, such as moving a toe or flexing a leg muscle.
The polygraph is still vulnerable to both physical and psychological countermeasures and it also suffers from a significant error rate based upon inconclusive, false positives, or false negatives results.
Manipulation During Control Questions:
- Subjects may control their breathing
- Contraction of sphincter muscles
- Biting the tongue or inside of mouth
- Thinking about horrible things
Manipulation During Relevant Questions
- Practicing relaxation techniques
- Doing mental calculations
- Thinking of calming subjects
Former polygraph examiner and Oklahoma City Detective Sergeant Doug Williams was sentenced to two years in prison by the federal government in 2015 for activities associated with his teaching people how to beat the polygraph. After years of using the technology, he came to distrust the results and taught thousands of people to use countermeasures. He rates the accuracy of the polygraph at 50 percent at most. In fact, U.S. government agencies have taught individuals involved in undercover operations to beat the polygraph, thus validating Williams claim that techniques can be taught to defeat the polygraph.