Have you ever told a lie? Did you ever think youd get caught? Do you believe other people can tell if you are lying? Do you believe that a computerized machine that measures changes in an individuals respiration, heart rate, blood pressure, and perspiration in response to questions proposed by another human, can determine a persons truthfulness? Do you think we all might have something to gain by finding out about this exact, or not so exact, science?

The machine accredited with these properties, the polygraph, from the Greek meaning many writings, was invented in 1902, improved in 1921, and evolved from a manual or analogue instrument, to an electrically enhanced system, to a computerized digital system.

According to Erika Thiel, Licensed Professional Counselor (LPC) and Director 5 of the American Polygraph Association (APA): The polygraph is a measurement of psychophysiological data. This means there are components that are placed on a persons body that measure the biological responses to a persons thoughts/emotions/distortions towards a question. When a persons body responds to the questions that the examiner designs to help the client pass their test, then the person is considered to be telling the truth. When a persons body responds more to the questions about the relevant topic they came to be tested on then they are considered to not fully be telling the truth. Ultimately, we are looking to see if the person has told us all the information necessary to pass their test.

The components that Thiel references are rubber tubes wrapped around the waist and chest to measure respiration, a cuff on the upper arm to monitor blood pressure and heart rate, and tabs on the fingers to monitor perspiration. As polygraphers pose questions based on a pretest interview, their subjects responses, logged into a computer, are recorded and displayed as swiggling lines across a computer monitor. Early polygraphs would ultimately generate this information printed on long, rectangular paper charts.

The polygrapher asks a series of questions. These questions are referred to as 1) Irrelevant Questions to more or less establish a baseline: Is your name John Doe?; 2) Relevant [or what I call hot] Questions: Did you take the $50,000?; and, very often, 3) Control Questions: Have you ever taken any money from anywhere in your lifetime? to compare the difference in the responses between the Relevant and Control questions and see if the interviewee might be of the nature to be involved in the subject of the Relevant questions.

After the polygraph reviews the test results, a person may be said to have 1) passed the polygraph meaning they have been truthful 2) failed the polygraph meaning they have lied or 3) had a test that was determined inconclusive meaning that the results could not determine truth or deception.

According to Thiel, Some of the main types of tests are post-conviction sex offender testing, criminal investigation type testing, pre-employment type testing, community safety type testing (such as domestic violence or drug use), and tests that are done as disputes between family/friends. The entities are broken into three sections- Private Examiners, Government Examiners and Law Enforcement Examiners.

So, is this instrument capable of accurately measuring truth? Some polygraph practitioners have told us that polygraph test results are often contingent on the accuracy of the examiner. They expressed that the test cannot be beat, but the examiner may be.

Yes if you have a properly trained examiner utilizing a validated technique, then the polygraph can be a valuable instrument in the detection of deception, says Joseph P. Buckley III, forensic interviewer, polygrapher, and president of John E. Reid and Associates, Chicago.

Thiel comments: The polygraph will never be 100% accurate due to human error; however, research shows that the polygraph can have a confidence interval in the 80s to 90s depending on test type.

The Internet displays a plethora of information about beating the polygraph. Some say if you elevate the components (the respiration, heart rate, blood pressure, and perspiration) by doing something like stepping on a tack in your shoe, biting your tongue, squeezing your butt, or thinking of a positive distraction when being asked the control and irrelevant [more mundane] questions, the response to the relevant [or hot] questions, would not be as significant. Advice from the pros, many of those responsible for pre-employment polygraphs, is dont even think of it! An experienced polygraphed will know what you are doing!

A quick and dirty random survey of individuals, age 23-35, concluded that all had some concept of what a polygraph was, stating it was a lie detector, as depicted on television or in the movies. Over the decades those shady polygraph scenarios have popped up in crime capers, spy thrillers, gumshoe escapades and docudramas.

In 1948, Leonarde Keeler, who was responsible for adding the galvanometer, a device to measure the skins electrical response, to an early version of the polygraph, played himself in the classic noir movie, Call Northside 777. James Stewart starred in this historic piece based on the real-life efforts of Chicago Times reporter James McGuire to clear Joe Majczek, a Chicago man who had spent 11 years in a Joliet prison for the murder of a police officer.

More recently, theres the comic scene in Meet The Parents where Robert DeNiro questions a very nervous Ben Stiller, hooked up to a polygraph, on a variety of topics including whether he ate undercooked, a little rare, roast beef for dinner. In The Politician the polygraph examiner blurts outright, Shes telling the truth! during the examination. Then theres the scene in the movie Nothing But The Truth where Erica Van Doren (Vera Farmiga) is given a lie detector test because the CIA suspects that she leaked her own identity. Director Rod Lurie brought in a real life polygrapher for the scene. The once popular Australian-American science entertainment television program Myth Busters did a segment questioning as to whether it was possible to beat the box.

So has the actual polygraph machine changed much over the decades?

Thiel comments, The polygraph instrument itself has not changed all too much throughout history. There have been more components added, but the basic components used have ultimately been around from the beginning. The technology has improved by changing from manual testing to computer testing and there has been more research done on test technique and scoring method. As we move on throughout the years we get better at understanding the ways thoughts impact our biological reactions but since the human brain has not changed, the polygraph itself has not had massive changes.

Buckley adds, The primary change in the polygraph instrumentation over the last several decades has been the incorporation of a computer algorithm to read/interpret the physiological data recored by the instrument (respiration, bold pressure and the Galvanic Skin Response), which then provides the examiner with an assessment (via a numerical score) as to whether or not the subject is being deceptive. There are ongoing efforts to research whether other physiological data that might be helpful in the detection of deception, such as brainwaves, but no commercial instrument has been developed to incorporate any additional physiological responses.

Some question whether the computerized polygraph is a more accurate means of detecting lies than the former analogue system? Buckley has this to say: In my opinion it is not, because there are too many variables that can affect a persons physiology. When you consider such evidence as DNA, fingerprints, ballistics, etc., there are some objective criteria to examine, but with the polygraph technique you are measuring physiological responses that are influenced by the subjects emotional state. For example, a subject who is legitimately angry can show the same physiological changes (as recorded by the polygraph instrument) as a person who is being deceptive there is no way that a computer algorithm can make that distinction, but a trained examiner can. The examiner is an essential element in the polygraph process to assess the variables that can influence the recordings.

So, at the end of the day, or the end of the article, are you still not sure what you think about the polygraph? Makes sense. Guess the only sure deal is knowing the value of truthfulness and the consequences of practicing its alternative:

People think that a liar gains a victory over his victim. What Ive learned is that a lie is an act of self-abdication, because one surrenders ones reality to the person to whom one lies, making that person ones master, condemning oneself from then on to faking the sort of reality that persons view requires to be fakedThe man who lies to the world, is the worlds slave from then onThere are no white lies, there is only the blackest of destruction, and a white lie is the blackest of all. Ayn Rand

Excerpt from:
Off The Beaten Path: To Tell The Truth - Journal & Topics Newspapers Online