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Taking the Mystery Out of the Polygraph Test

Taking the Mystery Out of the Polygraph Test

Sergeant Betsy Brantner Smith

A polygraph exam is often a “make or break” part of the police testing process, but it’s often difficult to prepare for and even understand. As Richard Nixon said “I don’t know anything about lie detectors other than they scare the hell out of people!” Polygraph testing is used far more in government pre-employment processes than in the private sector. In recognition of this, the APA Research Center at Michigan State University surveyed 699 police executives from some of the largest police agencies in the United States to determine the extent of, and conditions in which, polygraph testing is being used for pre-employment screening (this survey excluded federal agencies). The major results of the survey showed that of the respondents 62% had an active polygraph screening program, 31% did not and 7% had discontinued polygraph screening. Admittedly, polygraphy is not an exact science, but if it’s going to be a part of your next law enforcement employment process, take the time to learn the basics.

The polygraph, or “lie detector” is an instrument that measures and records physiological responses like breathing rate, pulse, blood pressure and perspiration. The underlying theory of the polygraph is that when people lie they get measurably nervous about lying. Its name stems from “poly” for the multiple sensors used and “graph” for a single strip of moving paper that records information, although most polygraph examiners now use computer images instead of analog instrumentation. A polygraph examiner is generally a highly trained interrogator as well as the technical operator of the devise and will use their experience in addition to the machine to detect your truthfulness.

One of the most intimidating parts of the polygraph exam is being attached to the sensors that will collect physiological data from at least three systems in the human body. After being attached to four to six sensors, your polygraph exam will likely start with a pre-test interview to gain some preliminary information which will later be used for control questions; this is called the “Control Question Test,” or CQT. Often, the examiner may ask you to deliberately lie several times to test your responses; this is a “Directed Lie Test,” the DLT. They may also ask “probable-lie” questions, such as “have you ever stolen anything?” (even the most honest person has “stolen” a pen from work or a candy bar from their little sister or some other “theft” that concerns them enough to show a stress response when answering).

Finally, they may use the “Guilty Knowledge Test,” GKT, a test that compares physiological responses to multiple-choice type questions about particular facts that only the examiner and you would know. The majority of American Psychological Association members surveyed think that the GKT is the most accurate of these tests and consider it “a promising forensic tool.” However, polygraph testing is still largely controversial in the U.S., so why do so many police agencies use it?

In the Michigan State survey the great majority of the agencies using polygraphs indicate that lie detectors reveal information that cannot be obtained by other selection methods. They also stated that polygraph testing makes it easier to establish background information, that it deters undesirable applicants, and that it is faster than other methods of selection. About half of the agencies using polygraph testing for sworn positions also use it for non-sworn employment, such as dispatchers, records clerks, and even secretarial personnel.

CIA operative-turned-spy Aldrich Ames, convicted in 1994 of spying for the Soviet Union, famously passed several lie detector tests by allegedly being told by his Soviet handler to "Get a good night’s sleep, and rest, and go into the test rested and relaxed. Be nice to the polygraph examiner, develop a rapport, and be cooperative and try to maintain your calm.” Often subjects are also told to try and control their breathing or artificially raise their heart rate during control questions (IE: thinking about a scary movie scene even while you are telling the truth), but the bottom line is this: tell the truth.

Come to your polygraph exam well-rested and well-fed, dress appropriately, and answer the questions truthfully to the best of your ability. Most police agencies don’t expect you have lead a perfect life, but they do expect you to be truthful. After all, law enforcement is profession of honor and integrity. Good luck.


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  • Mark_twain_and_me_max50

    mexilad

    almost 4 years ago

    82 Comments

    Aldrich Ames and Robert Phillip Hanssen both passed polygraph exams while they were actively spying against the United States. It can help a backgound investigator to focus their investigative efforts, but that is about it.

  • 687-45b_5270

    JCastelot

    about 4 years ago

    228 Comments

    Going through the hiring process soon and hearing stories about people who are innocent not getting jobs because of a "failed" poly and I feel that it is my biggest fear. I feel that they should not be used in hiring. I feel that the background check will unlock more about a person than a machine will.

  • Thumbnailcaf8y9in_max50

    edoering84

    about 4 years ago

    996 Comments

    I think poly's are useless or the examiner didnt know how to read it in my case. Poor guy took three tries to guess the number i was lying about in the control test. Either that or im a very good at lieing! lol

  • B-25_max50

    michaelramz

    about 4 years ago

    36 Comments

    My opinion is that the polygraph should be taken out of the hiring process. While a lot of information about a person can be learned with a polygraph, there are way too many inconsistencies in the testing and too many ways that a polygraph can be defeated.

  • Photo_user_blank_big

    FlyingDutchman

    about 4 years ago

    178 Comments

    irony of the "lie detector"

  • Photo_user_blank_big

    Anonymous

    about 4 years ago

    Sorry to say it, but this article doesn't "take the mystery out any polygraph test".
    It is, nevetheless informative. Perhaps some good advice for potential applicants to prepare themselves and have some knowledge of what to expect.

    That said, my personal (and modest) opinion on "Lie Detectors" of any kind: They are USELESS.
    One day, using science and applied technology we should be able to develop a TRUE LIE DETECTOR... So far, no good.

  • Dscn0026_max50

    tinbadge50

    about 4 years ago

    84 Comments

    I am a former poly examiner. I switched agencies and decided not to continue doing exams. Why? Because they simply don't work as advertised. I have had people have "deceptive" test results who were later determined to be innocent (myself included). When I took my poly exam back in the day, I was asked if I "ever used marijuana?". I said "no", since I never have, but was nervous because of the fact that most people have used it. I ended up reacting to the question. Luckily the examiner believed me rather than his charts. But the school that trained me stated "score your charts and believe them". Folks, life is not so black and white. Without a doubt, nervousness can effect the outcame of the test. If you are applying to be a cop, you must get all of your past garbage out on the table prior to the test. You will still be nervous, but hopefully less nervous. Final point, the multi-issue format of the pre-employment examination is also known as a "fishing expedition", and is the most unreliable format as far as accuracy is concerned. Most of these tests end up "inconclusive". The main point of the process is to get you to spill your beans before the test. Be polite, professional, articulate and personable with the examiner, because the way you actually present yourself prior to the test during pre-test questioning can really make the difference between failing or passing the process. The polygraph itself, in my opinion, is all smoke and mirrors. I think it could be improved if it integrated voice stress technology, but both of those industries compete against each other so it's never gonna happen. For learning the "real" truth, nothing compares to an extensive background or criminal investigation. My 2 cents!

  • Photo_user_blank_big

    Anonymous

    about 4 years ago

    @ mucholucho Congrats! I read your previous post and got a laugh, I'm the same way so it's what I'm nervous about too. Glad to hear you passed with flying colors... I won't worry about those pens anymore =P

  • Img_3265_max50

    mucholucho

    about 4 years ago

    214 Comments

    Follow up - I PASSED! It was really kind of neat. I talked with the examiner for about 2.5 hours about everything and anything. He had his list of question, "have you ever..... when....how many times? etc. etc." but we would deviate from the questions and talk about all kinds of things -family, religion, politics, etc.
    Then came the testing! I suddenly began to feel nervous and I thought I was going fail for sure. I don't know why, but I guess after laying out my dirty laundry, I felt really guilty or something. Anyway, the poly lasted about 8 minutes and I tried to remain as calm as possible. All went well apparently b/c I received my conditional letter of hire.
    Qeustions for those who asked:
    Have you ever stolen from an employer?
    Have you ever lied?
    Have you ever used drugs?
    Have you ever sold drugs?
    Have you ever looked at "kiddie porn"?
    Have you ever been a peeping tom?
    Have you ever hired a prostitute?
    What drugs did you use?
    When was the last time you used drugs?
    have you ever committed a crime that you have not been convicted of?
    And, many, many more.
    Then out of all these, when I was hooked up to the machine he maybe asked some 20 questions and we were done.

  • Christmas_picture_1_max50

    diderr

    about 4 years ago

    66 Comments

    The polygraph is the only real thing I'm afraid of during the screening process. I'm afraid even if I tell the truth I will somehow fail. I understand how the machine works, but I don't know how they base information that the test reads. I personally don't think the machine is entirely accurate. Is that why it's not used in courts anymore? I have a college prof that swears the poly is 99.9% accurate.

  • Img_3265_max50

    mucholucho

    over 4 years ago

    214 Comments

    Mine is in 30 minutes, AAAAHAHHAHAHAHAHAAHAH! Honestly I am kind of freaked, I am trying to keep my cool but, I am afraid of blanket questions -"have you ever lied, have you ever stolen, have you ever....etc.
    I was lying in bed and I am thinking to myself, "Did I ever steal money from an employer? and I suddenly remembered that I did on 2 occasions when I worked for Wendy's when I was 17 (now I am 33). I couldn't remember that distant detail in my oral board and Background investigation last month and I told the investigators -No. Now what, this is nuts. What if I am not "sure" if I ever did X or Y in my past, I think I will answer nervously or in doubt.......Ahahahahaha 25 minutes!!

  • Photo_user_blank_big

    Anonymous

    over 4 years ago

    Also the Plygee. does not hold up in court. does it?

  • Photo_user_blank_big

    Anonymous

    over 4 years ago

    My God if Bill Clinton can pass it everyone of us home free!!

  • Voiced_max50

    boxingbabe

    over 4 years ago

    2 Comments

    just the thought of a polygraph test frightens me!...I havent led a bad life or nothing,but im the kind of person that gets nervous and feels guilty even if i havent done a thing..go figure. Im afraid I'll fail it even if im being truthful.You think or am i just paranoid?

  • Photo_user_blank_big

    Anonymous

    over 4 years ago

    what are some ?'s asked on the test?

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