Using Polygraphs for Employment Screening - You've Got to be Kidding

February 6, 2008

The National Post recently ran an article titled ‘How they do it at the Precinct’. In it, the writer argues that while police interrogators and interviewers share a common desire to glean information from another party, police have become far more ‘sophisticated’ in achieving their goals. The writer proceeds to provide tips from police interrogators on getting people to ‘talk’.

The article then veers dangerously down another path. It discusses the use of polygraphs by police and attempts to make the case for their use in employment situations. It even quotes the manager of an Edmonton-based consulting firm who suggests that over 15% of his clients are now ‘corporate’ users who apply polygraphs for employment verification testing. The writer argues that the use of polygraph testing is a growing trend that should be watched for in the selection trenches. This can only be described as ludicrous.

The polygraph was first developed in the late 1800s by William Moulton Marston who is better known for having created the cartoon character ‘Wonder Woman’. Polygraphs are but one of many techniques developed over time to test for honesty. Ancient Chinese believed that liars generated less saliva than honest citizens so they asked suspects to chew a bowl of rice and spit it out so for weighing. The Greeks had an elaborate plan to assess facial features and gestures in distinguishing the honest from the deceitful. In medieval times, suspected liars were asked to lick a hot poker. If God wanted to commend their honesty, their tongues would not be burned.

Polygraphs are a decidedly American phenomenon with few other countries in the world embracing their use to the same degree. The machine works on the assumption that body changes accompany mental activity. By recording how individual bodies respond to questions, polygraphs purport to detect lies. Proponents argue that polygraphs are science, the original DNA testing if you will. They note that it is the polygraph machine and not the examiner which does the assessing. Much like an IQ test, polygraphs spit out numbers and the numbers always tell the tale. As the president of Edmonton-based polygraph services company, ITR (it stands for Is That Right), states in a subsequent National Post article, “It’s scientifically proven to detect deception…it cannot be beaten”.

But the numbers do lie, and quite regularly. While the graphs reflect body changes and emotions they must be interpreted by the examiner who has wide discretion over the findings. There is little science explaining how the body responses of the deceiver differ from the anxious innocent subject. As a window into the soul, the test is notoriously opaque and unreliable.

Furthermore, lie detector tests can only work if people are persuaded that they work. Even die hard proponents agree that the lie detector works as a classic placebo in which people have to believe it works in order for it to have any chance of working. As Ken Adler points out in his book The Lie Detectors, the device is an intensifier which heightens the subject’s self-consciousness in the hope of prompting self-disclosure. In some ways, it is similar to placing your hand on the Bible in a court of law. It raises the stakes, “the one by reference to the all-seeing eye of God, the other to the all-seeing eye of science”. The problem is, of course, that there is a wide variation in how liars, criminals, psychopaths and good guys respond to such a placebo. Polygraphs have never stood the test of science that it purports to represent.

Though its packaging has been updated, the basic technology behind the polygraph has hardly changed since the 1920s. Since that time it has been used to ‘out’ an assortment of communists, criminals and homosexuals. Though its popularity was on a decided decline in the 90’s, events surrounding 9/11 have propelled the polygraph back to a position of prominence in the US where it is now purportedly widely used as a tool by counter-terrorism experts and Homeland Security. The tool remains the defacto ‘truth serum’ and a month does not pass without some prominent businessperson, athlete or movie star demanding the opportunity to clear their name by submitting to a lie detector test. Just a few weeks ago, 60 Minutes’ correspondent Mike Wallace asked baseball pitcher Roger Clemens if he would submit to a lie detector test in order to clear his name in the ongoing steroids scandal. A new reality program, called The Moment of Truth will strap contestants to a polygraph before asking them a battery of personal, and likely embarrassing questions. All of this despite little evidence of the efficacy of the technology or the underlying assumptions about the relationship between deception and bodily reaction.

Let’s hope that it was a just slow news day in the National Post and that this ‘trend’ never makes its way to the employment trenches.