The Test

Because the polygraph is a portable machine, a lie detector test can take place in almost any surroundings. Sometimes subjects are directed to go to the examiner's office for the test. Other examiners may visit the company or other locale where people are to be tested and set up shop in any available room or office. Some examiners prefer to bring their own office with them and work out of a trailer or camper in the parking lot. In general, the room in which the test is given should be reasonably plain so as not to distract the subject. Some polygraph examiners, in an effort to heighten subjects' perception of the test as a professional procedure, go so far as to wear a white coat, stethoscope dangling from the neck, and to spray the air of the examining room with ethyl alcohol.^[31] About the only piece of furniture specifically designed for lie detection is a straight-backed chair with concave armrests long enough to provide support for the subject's hands, where the fingertip clips are attached. This is not essential, however, for the test can be effectively conducted with the subject's arm resting on a table or on chair arms of normal length.

The typical lie detector test begins with a pretest interview. The examiner explains how the polygraph machine works and reviews the questions to be asked. While most polygraph examiners agree that the pretest interview is an extremely important part of the overall process because it sets the general ambience for the test, they are not of one mind as to precisely what that ambience should be. Some attempt to set the subject at ease, while others strive to increase nervous tension. In the latter case, the examiner's goal is often not so much to conduct a reliable polygraph test as it is to extract a confession. A police officer told me that occasionally the polygraph is used in this manner as a last resort in cases where the evidence against a suspect is not conclusive and the likelihood of a conviction is small. The suspect is told that things look very bad but that it might be possible to clear the record by means of a polygraph test. If the person can be induced to confess during the course of the test, charges will be filed (on the basis of the confession, not the polygraph test). If not, the suspect will

be released regardless of what the polygraph chart shows about innocence or guilt (the evidence of polygraph tests rarely being accepted in court).

The polygraph is an effective tool in the hands of a skilled interrogator, who can use it to help convince suspects that their lies are not fooling anyone. When the aim is confession, other interrogation techniques may be used in the pretest interview, such as the suggestion of one polygraph instructor that the questioner sit close to the subject and that there be no table or other obstacle between them. Any kind of obstacle gives the person being questioned a certain degree of relief and confidence. The questioner may start with his chair two or three feet away and move closer as the questioning proceeds, so that ultimately the knees are in close proximity. This physical invasion of the subject's territory by the questioner, the crowding in as he is questioned, has been found in practice to be extremely useful in breaking down a subject's resistance. When a person's territorial defenses are weakened or intruded on, his self-assurance tends to grow weaker.^[32]

Whether or not the examiner wishes to intimidate the subject, a ubiquitous aim of the pretest interview is to convince the subject that the polygraph really works. "The polygraphist . . . ," writes Abrams, "must engender enough of a feeling of confidence in the subject to relieve the anxiety of the innocent and at the same time increase the fear of the guilty."^[33] Fred Inbau and John Reid suggest that the examiner tell the subject quite emphatically, "if you're telling the truth this machine will show it; if you're not, the machine will show that, too."^[34] An examiner I interviewed habitually tells subjects just prior to the test, "Every story has three sides—your side, his side, and the truth. This machine is going to get the truth."

Lie detector tests are used not only to ascertain the subject's own improprieties but also to learn what one may know, or suspect, about the wrongdoings of others. The stage is often set for this during the pretest interview by convincing the subject that "divulgence of the suspicions is necessary for the subject's own test purposes."^[35] The polygraph, that is to say, is presented as a machine with rather mysterious properties that necessitate that a

person betray any suspicions about other employees or suspects to be found innocent oneself.

One common means of instilling respect for the machine is to run a "stim" (stimulation) test prior to the actual test.^[36] The examiner, saying that he is going to demonstrate the accuracy of the polygraph, hooks the subject up to the machine and directs her, in one type of stim test, to draw a card from a deck. The subject is told to sit still, look straight ahead, and, for the purposes of the stim test, answer "no" to all questions. The examiner proceeds to ask if it is any of a number of possible cards and then identifies the correct card on the basis of the polygraph chart readings. (Some polygraph examiners, it seems, cover their bets on the stim test by using a trick deck of cards.)^[37]

Actual examinations vary according to whether they are concerned with the subject's general honesty and history of wrongdoing (as in applicant screenings and periodic and random tests of current employees) or are part of the investigation of a specific crime. In general, however, the test consists of some ten to fifteen questions of three basic types. Irrelevant questions have to do with nonthreatening matters regarding which the subject can fully be expected to give honest answers: questions such as "Is today Thursday?" or "Do you live in Chicago?" or "Were you born in 1946?" The chart readings for these questions depict the subject's physiological profile when responding truthfully. Control questions are designed to be threatening and to evoke an untruthful response from anyone. These may vary a good deal with the particular sort of wrongdoing one is interested in uncovering and the particular history of the subject. For a person with a criminal record, a control question might be, "Did you ever commit a crime that was not found out by the police?" A person being investigated for assault might be asked, "Did you ever desire to hurt anyone?" An applicant in a preemployment screening might be asked, "Did you ever steal anything?" The chart readings for control questions show the physiological signs of anxiety connected with deception. Finally, the relevant questions (or "hot" questions, as they are often called in the trade) pertain to the particular issue under investigation. If this is a specific crime, the question focuses directly on it, such as, "Did you rape Judy Barnes

on July 17?" or "Do you know who stole $500 from the cash register two weeks ago?" Relevant questions in periodic tests of current employees or applicant screenings are perforce somewhat more general, such as, "Have you stolen any money from the company during the last six months?" or "Did you steal any merchandise from your previous employer?" or "Have you ever been fired for reasons of dishonesty?"

Analysis of the chart is basically a matter of comparing responses to the relevant questions with those to the irrelevant and control questions. If the subject is lying in responding to the relevant questions, the readings for them will resemble those for the control questions; if the subject is telling the truth, they will resemble the readings for the irrelevant questions. Or, phrased somewhat differently, a deceptive subject will show greater perturbations for the relevant questions than for the control questions, while a nondeceptive subject will react more strongly to the control questions. The reason is that the guilty individual is more threatened by the relevant questions than the control questions, while the innocent individual, having nothing to fear from the relevant questions, is more threatened by the control questions.^[38] Test results are usually reported as "DI" (deception indicated), "NDI" (no deception indicated), or "Inconclusive." The last is used when no clear pattern is discernible on the charts.

Polygraph examiners are interested in creating conditions in which the charts will be as "good" as possible; charts, that is to say, that lend themselves most unequivocally to an interpretation of either DI or NDI. Examiners may differ, however, on how to bring about these optimal conditions. According to Phillip Davis and Pamela McKenzie-Rundle (herself a former polygraph examiner), the subject who has been "pumped up" during the pretest interview is most likely to produce the sharply different responses to relevant, irrelevant, and control questions that are essential for "good" charts.^[39] However, a polygraph instructor told me that his main goal is to put subjects at ease during the pretest interview, partly to facilitate the production of "good" charts. An overly nervous subject, he explained, is likely to give erratic responses even to the irrelevant questions. This makes the chart as a whole much more difficult to interpret and produces a result of Incon-

clusive. Moreover, the subject who has been "pumped up" by the test situation may even be driven by the pressure to make a false confession.

A careful polygraph test involves running several charts, that is, going through the same set of questions three or more times, with periods of interview/interrogation in between. This provides additional opportunities for the subject to make a confession, or, conversely, for areas of apparent deception or guilt that showed up on the first chart to be resolved in the subject's favor. In either event, the charts and the overall result of the test are clarified with repetition.

One technique for such clarification, which seldom works to the benefit of the subject, is the following:

Once a test has been administered to a guilty individual it is extremely effective to display the records to him and point out the deception criteria—at the same time reminding the subject that the recordings represent his own heart beats, his own blood pressure changes, etc., and not those picked up by the machine out of thin air or placed there by the examiner.^[40]

A particularly powerful technique is to go through the test two or three more times, pointing out to the suspect how, with each successive chart, the indications of deception become more pronounced. Eventually the evidence from the polygraph becomes so self-evident that only the most intransigent subject can avoid confessing.

But, of course, the alternative explanation is not difficult to imagine. Subjects "hit" more and more decisively on the relevant question with repeated testing not necessarily because of guilt but because they are distressed about how the response to it appears on the previous chart and are increasingly apprehensive about it when the test is run again.^[41] This, incidentally, sheds additional light on the practice of reviewing the questions with subjects prior to administering the test. This is done, they are told, as an assurance that no surprise questions will be sprung while the chart is running. That is true enough, but the practice also has certain advantages for the test itself which are not so

immediately apparent. For one, a subject might be surprised by an unexpected question, and even if the person has nothing to hide on that question, the surprise itself could produce physiological responses that might be difficult to distinguish from those associated with deception.^[42] For another, to review all questions in advance alerts deceptive subjects to just when in the test a relevant question is coming. Their attention focuses on it, and they become increasingly apprehensive as it approaches and then relax after it has passed. This produces a characteristic response pattern known as "peak of tension," which is taken as particularly damning.

Is is possible, however, that the peak of tension might also characterize the responses of innocent individuals who go into lie detector tests knowing full well that they are suspected of certain misdeeds and who therefore are apprehensive about the relevant questions. This is obviated in another testing format, known as the Guilty Knowledge Test.^[43] Suitable only for investigations into specific acts of wrongdoing and not for general preemployment or periodical checkups, the Guilty Knowledge Test trades on information that only the guilty individual would know. The precise location of a rape, for example, or some characteristic of the clothes the victim was wearing might not have been made public. One could then construct a polygraph test with a series of alternatives, for example, she was wearing a red blouse, a blue blouse, a sweatshirt, a woolen sweater, and so on. Regardless of how much anxiety an innocent suspect might have about the test, he would not be likely to "hit" on the correct alternative because he simply does not know it. The guilty suspect, however, is much more likely to react. And if the possibilities and the order in which questions would be asked were reviewed in advance, it is reasonable to expect that the responses would manifest the typical peak of tension pattern.

Polygraph examiners I have interviewed enjoy telling stories of their most interesting cases, including their greatest triumphs. One of these was a classic use of the Guilty Knowledge Test and is interesting in addition because it demonstrates that the verbal answers given by the subject are really not an essential part of the test. A murder suspect agreed to be hooked up to a polygraph but

refused to answer any questions. "That's all right," said the examiner, "all you have to do is to sit there." He informed the subject that they were going to find out just where the body was hidden. He produced a map of the city, divided it into quadrants, and, pointing to each in turn, asked, "Did you hide the body in this section? In this section?" and so on. Although the subject sat mute, the chart showed a larger response for one of the quadrants than for the other three. The examiner divided that section into quadrants and repeated the questions. The narrowing process continued with, it can be imagined, the subject becoming increasingly apprehensive. Finally, a bit of territory the size of a house lot was specified. The police dug there and discovered the body.

Polygraph examiners may use ingenious—if on occasion remarkably simple—techniques to ascertain if someone is lying. Keeler, who also tried the technique of identifying the location of a body by means of pointing to quadrants on a map,^[44] was once asked to use the polygraph to determine if an individual who claimed to be blind was in fact so. Keeler did not find it necessary to ask any questions of the individual at all. He simply hooked him up to the polygraph and then held a picture of a nude pinup girl in front of him. The needles went wild, and they had their answer.^[45]

Polygraph subjects too have developed a set of techniques—some simple and some more ingenious—to "beat" lie detector tests. The technique that usually first springs to mind, especially among persons with little experience of the polygraph, is to maintain such rigid control over one's physiology that no telltale perturbations will disturb the polygraph when one lies. This is extremely difficult to accomplish, although in one case an enterprising individual may have made it work. A highly experienced examiner told me about a subject whom he had tested before and whose previous tests had indicated a great deal of deception. This time, however, the charts indicated no deception at all; they looked, indeed, too perfect. The examiner said to the subject, "This is too good to be true. What are you doing?" The subject, apparently prouder of his ruse than apprehensive about being discovered in an effort to beat the test, unbuttoned his shirt and

displayed his torso, completely wrapped in aluminum foil. In principle, this should have no effect whatsoever on the polygraph readings, but the examiner surmised that the trick gave the subject such confidence that he succeeded in muting the physiological responses that normally accompany deception.

Another technique is to use some substance prior to the test in an effort to mask one's responses. Typewriter correction fluid such as White-Out is believed by some to be effective for this purpose. (Does the rationale have to do with some supposed generic capacity of the liquid to cover things up?) Subjects have been known to paint their fingertips with it to thwart the galvanic skin response measure—surely a ruse that would not be difficult to detect. Alternatively, the subject can drink it. One individual who was told by a friend that he could beat the test with correction fluid "drank five bottles of White-Out, threw up during the pretest interview, and confessed."^[46]

The most effective way to thwart a lie detector test, however, is not to attempt to minimize one's reactions to the relevant questions but to maximize them on the irrelevant and control questions. Chart analysis rests on identifying differences among these three types of question. The assumptions are that all subjects will show little reaction to irrelevant questions, that an innocent individual will react more strongly to control questions than relevant questions, and that a guilty subject will show the reverse profile. Thus, a conclusive finding of deceptiveness is not possible if the responses to control questions are stronger than to relevant questions,^[47] while the entire test is thwarted if responses to irrelevant questions are stronger than those to relevant or control questions.

Subjects may resort to a variety of techniques if they wish to intensify their responses to irrelevant or control questions. Pain is effective for this, and one practice is to come into the examination room with a tack in one's shoe and to press the foot down on it when one wants to provide a heightened response. Somewhat simpler is to bite one's tongue; easier still is to tighten the sphincter muscle, which produces a minor perturbation in the blood pressure. Finally, it is easy for any subject to confound a lie detector test simply by refusing to sit still. Wriggling, coughing,

and intentionally varying the rate of one's breathing all have the effect of defeating the polygraph's physiological measures. A common method to distort the readings produced by the psychological stress evaluator, which measures voice patterns, is to wear a necktie and to press one's throat against its large Windsor knot while answering irrelevant or control questions.

Many countermeasures are not difficult for the examiner to detect. People with tacks in their shoes often limp painfully into the examination room. Some examiners have subjects sit on an air-inflated pillow that is connected to the polygraph machine in order to detect sphincter tensing. And, of course, subjects who deliberately cough and squirm are often not even trying to hide their refusal to cooperate.

A deceptive subject who uses subtle techniques that escape the notice of the examiner may achieve the false negative test result of NDI (no deception indicated). The examiner who detects efforts to defeat the test is likely to attempt by cajoling or by threats to convince the subject to desist from them and to cooperate fully with the test. If the subject will not do so, it will be impossible for the examiner to reach a conclusion of DI (deception indicated) on the basis of the charts. The only option is to report an inconclusive test result, although very possibly with a notation on the report that the subject's refusal to cooperate might in itself indicate deception.