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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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    ksmac

    over 4 years ago

    24 Comments

    I had a 2 polygraphs that came back inconclusive. interesting thing was when they asked if i was attempting to deceive the instrument i said no and that showed that I was being truthful. Other parts of the poly werent conclusive. i told the truth 100 percent was offered the position both times then they recinded it due to the inconclusive poly both times. Polys are useless.

  • Usmcrlee_max50

    Never_Again

    over 4 years ago

    70 Comments

    If I am a liar and I told you "I am lying," am I lying?

  • Photo_user_blank_big

    CubexDE

    over 4 years ago

    6 Comments

    Penn and Teller did a great show on the polygraph, everyone who has to take it should watch it.

  • Photo_user_blank_big

    LegAdv

    over 4 years ago

    20 Comments

    It's an investigative tool; no more and no less. I anticipate that the fMRI will eventually replace the polygraph, although that would probably be several years into the future.

  • 1_max50

    rVic88

    over 4 years ago

    6 Comments

    Great information!

  • Jen1_max50

    Jennifer_S

    over 4 years ago

    602 Comments

    Good information... I don't get why people lie on these things. Fess up to what you have done and take ownership.

  • Photo_user_blank_big

    Anonymous

    over 4 years ago

    My biggest fear is i did stuff when i was 18&19 yrs old that i completly regrat.I'm 29 almost 30 and ihope it doesn't come back and bit me.I will tell the truth,but becoming a cop is all i wanted to do 4 about 7to8 yrs.Great add if nothing else.

  • Photo_user_blank_big

    Anonymous

    over 4 years ago

    Really, tell the truth here, nobody is perfect and everyone has had some small thing they have done they regret. If they see a pattern of it, be nervous but really, keep the work pens at work, lol.

  • 1393794_10151798561878138_392793313_n_max50

    Blueblood1974

    over 4 years ago

    5192 Comments

    Just tell the truth and do not think about nothing.lol,lol.

  • Swat_3_max50

    futuresniper1989

    over 4 years ago

    14 Comments

    well i havent taken it but Im not to worried about it

  • Delicate_arch_max50

    ryanhatch

    over 4 years ago

    1372 Comments

    Good advice. "Tell the truth". It's simple and the best way!

  • M

    twistermike45

    almost 5 years ago

    100 Comments

    Interesting article. I have never been around them so this was good information for me.

  • Tactical_rappelling_max50

    thinblueline74

    almost 5 years ago

    170 Comments

    Here's a problem I had recently with a pre-employment polygraph (and I've been a cop for several years now at another agency): The room it was held in was a tiny enclosed room surrounded with 'soundproofing". One problem: I'm extremely claustrophobic. I panicked and had to walk out of the interview. I eventually retook it at another point (but only after my doctor prescribed me medicine to get through the setting of the closed in space). It seems to me that in my case, the test was probably invalidated by what it took for me to be able to sit in that tiny room....can anyone fill me in? And also, I'm curious as to why it had to be held in such a small room?

  • Photo_user_blank_big

    rtj1012

    almost 5 years ago

    18 Comments

    Good information to know.

  • Photo_user_blank_big

    HotTruman

    almost 5 years ago

    4 Comments

    I have a question. Can agencies ask you questions about things you did as a juvenile on a polygraph? Even if they do, cant you ethically and truthfully say no, because technically, it doesnt apply jamerson44@yahoo.com is my address, thanks guys!!

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