I gave up doing 


years ago 

because I was 


doing what I

perceived as an 





Polygraph: Take It Or Leave It


 By Anonymous 


The author of this article has worked as a certified polygraphist, police lieutenant and licensed private investigator. He quit polygraph work because he felt many of the procedures were unethical. He has asked that his name not be used. This article may not be reprinted without the permission of the author, who retains all rights.

B ack in the sixties I taught a course in criminal investigation at Oakland City College. As is the practice of many teachers, I would occasionally bring in a guest lecturer or demonstration so my students would get a change of pace from the sound of my voice and so I could goof-off and get paid for it.

     One of my guests was the departmental polygraphist for a local police agency and he brought his instrumentation with him. After his basic explanation as to how the various components operated and how they were allegedly designed to monitor the physical reflexes that would give the examiner an indication as to the truth-telling propensity of the suspect, he asked for a volunteer. Somehow or other, I was elected. Up to that moment I had no experience with the so-called “lie detector,” never having been involved with its use. I was, however, a believer because of some of the things I had heard about its results. I cheerfully cooperated in the test which was designed to indicate whether or not the equipment was in good working order and tuned-in on the subject in order to operate accurately. The examiner explained that people came in different sizes and shapes and the instruments had to be adjusted accordingly if one were testing a male or female, a jockey or football player, a pregnant woman, etc.

     The testing involved the guinea pig selecting one of seven blind cards, cards placed face down with no markings or designations on the back. The person retained all the cards and made a mental note of the number he had chosen. After being attached to the device, he was instructed to answer nothing but “NO” when asked if he had chosen the various numbers. Then according to pitch, if the instrument is properly operating and adjusted, it would tell the expert on what number the lie had been told.

     Lo and behold, wouldn’t you know it ... the test worked like a charm and I was told the exact number I had chosen ... magic. I was a believer, and so was everyone in the class. If any of us had been taking a real examination, we would surely have known we were at the mercy of this great machine and would certainly have believed it was fruitless to lie to it. That’s what it is all about. If the tester can convince the subject he can’t “beat the machine,” he is putty in your hands.

     My rude awakening came years later when I spent six weeks in intensive study and practice at one of the nation’s most prestigious polygraph schools, long established and well-known, in New York City. I was taught the relatively simple card trick, the same one that had been performed on me years ago, and it was just a trick. The examiner knows in advance the number of the card chosen and his patter about having to check to see if the instruments are properly adjusted and operative on the individual is nothing but a sales talk designed to convince the person being tested that the process is infallible, so he might as well tell the truth in advance. That, in a nutshell, is the polygraph technique: Get the subject to confess by overwhelming him/her with a conviction that the lies will all come out so he/she might as well tell the truth.

     It is illegal for a police interrogator to promise reward or immunity in exchange for a confession, but a civilian polygraph examiner is under no such prohibition. Quite often, “It would be best if you tell the truth, rather than be called a liar,” is the statement that convinces the subject to tell all. It is then common for the examiner to submit a written report commending the subject for his/her truthfulness but, of course, delineating the incriminating admissions.

     The fake card trick was not the only ploy built into the school curriculum to give the examiner some help in reaching his conclusion. One such item was a serious plea to the testee to go to the washroom and scrub both hands thoroughly - because “the instruments won’t give me good results unless your hands are spotlessly clean.” When the person goes to the empty bathroom by himself, the examiner spies on his activity through a one-way mirror. If the individual seems intent on foiling the examination by failing to wash the hands, the examiner gets a pretty good hint that he is not a truthful person. Often one hears the water running and sees the individual pretending to wash his or her hands.

     A similar stunt is to leave him/her in the room alone with the polygraph itself, always laying on a stern injunction not to touch or even breathe on the equipment because “it’s so delicately balanced it will screw up all my results if it’s moved or shaken.” Once again a one-way mirror comes into play. It is amazing how many times one sees a wise-guy trying to loosen a wire or otherwise shake-up the instruments.

     In addition to a number of such physical procedures, there are numerous psychological traps designed to indicate truth or deception. For example, suppose we take a simple case of a man accused of car theft. A fake phone call is received by the examiner, who then turns to the subject and says, “What if I tell you that our identification technician just reported that he found your fingerprint on the car?”

     The innocent person will say something like, “That’s utterly and completely impossible.” The lying person may say something like, “Well you know anything is possible. I may have walked by the car in a parking lot or shopping center and accidently brushed against it.”

     Another part of the training that made me question the polygraph’s scientific infallibility was the instruction not to do any examination on a criminal matter without getting a copy of the police report and studying it carefully. We were even advised it was acceptable to telephone the officer handling the case to get additional details. It occurred to me that there must be a weakness somewhere in the procedure if such additional help was required. After all, a lab technician does a blood test without asking for your life’s history.

     I could go on and on about the nuts and bolts of the process itself, but the bottom line is, we were required to memorize about a ten-page script to take us through the entire session verbatim. In a way, it smacked of door-to-door selling or TV direct marketing.

     The standard polygraph instrumentation consists of a blood pressure cuff, an electrical connection to the thumb (plethysmograph), and two devices to measure chest and stomach respiration activity. All four are hooked-up to pens which inscribe their movement on a graph. This graph is what the examiner has at the end of the test to refer to for his final conclusion if a confession is not obtained. Unless something overt has occurred during the course of the examination, the “expert” has to rely on his gut reaction, his experience, his overall ability, etc. There is no question that some examiners become quite skillful at making accurate assessments, but often the charts are about worthless.

     Theoretically, the instruments work as follows: The blood pressure cuff is used on the theory that telling a lie creates an increase in heart action. The thumb connection, allegedly, measures increased perspiration (sweat being a good conductor of electricity), another alleged indicator of lying. The breathing measuring devices supposedly work along similar lines, that the stress of telling a lie increases the activity.

     A case I had makes a point. I was undecided as to how to write my report because I was having trouble making up my mind about the individual and deciphering my charts. During the test he claimed truthfulness throughout. I had tested him twice, just to be sure. I showed my charts to two other certified examiners and there was a difference of opinion. So I then took them to Los Angeles where there was a statewide convention of the California Association of Polygraph Examiners. I showed my charts to three different acknowledged “experts” in the field. I got three different interpretations of my results: lying, truthful and inconclusive.

     Most pre-employment testing is a fake examination in that not enough time is allotted to do the job properly. A routine examination is supposed to require two and one-half hours, but a pre-employment exam usually lasts less than one hour. I visited a fellow graduate a number of months after we got out of school and he was running eight exams of police applicants daily. Our training stressed a maximum of two tests per day. I asked him why. He told me he eliminated much of the technique and concentrated on convincing the subject he couldn’t lie and get away with it. He was getting good results weeding out undesirable candidates who would voluntarily incriminate themselves.

     I did a few of those myself and was amazed at what people would admit once they were convinced they couldn’t beat the machine and they would be forgiven all sins once they started off with a clean slate by telling the truth here and now. I recall two cases where the subject had already been cleared through routine police background checks for applicants, yet my examination divulged previous arrests which did not show up on any rapsheet because the individuals were not fingerprinted at the time of the arrests.

     I gave up doing polygraphs years ago because I was uncomfortable doing what I perceived as an unethical procedure. However, none of the above criticism diminishes in any way the value of a polygraph examination in its use as an interrogative device in criminal matters.

     A skilled and clever examiner can often get results that will shortcut unnecessary trials and the extensive and time-consuming investigation of “red herring” and false alibi tales. Polygraph can definitely pay off in terms of saving time, manpower and expense (taxpayer, take note). Polygraph should never be allowed in a court of law. It is just not reliable enough, regardless of the examiner’s skill and experience. There are some examiners who have no more ethics than a used car salesman. There are a number of ways of jiggering the results imperceptibly. Short of a complete confession in writing and properly witnessed, anything else should be barred from court. Given a total confession or even some pertinent admission, the polygraph examination results are not needed in court.

     There have been cases where the defense in a criminal matter produces an examiner who states the subject is truthful when he denies the act charged. This should never be allowed to influence the District Attorney, judge, jury or probation officer. There is nothing to prevent a sharp defense attorney from shopping around for a favorable opinion. The way it can work is, he gets Examiner A to run the test on a very confidential basis. If his guy fails the test, he then goes to Examiner B and buys another very confidential test. He goes on and on, until he strikes paydirt. He then waves those results around and talks about his client’s innocence. Polygraph examiners generally keep their tests confidential, so only the last examination is publicized. Of course, this stunt can only be worked when the defendant is out on bail. For example, it couldn’t be done in the Simpson case, or we might have heard about it.

     I have always made two statements about polygraph. For one, I have said that if the examiner has a police report which appears to be totally conclusive regarding the defendant’s involvement, no examiner will clear him on the polygraph. Even more strongly, given such a police report which absolutely nails the tested individual to the crime, if, by some trickery or false identification, an uninvolved person is substituted for the defendant such that this totally innocent person takes the test in his place, the results will come out as “lying.”

     In my 20 years of involvement in this field, I have never learned anything to make me change those statements.

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