Polygraph Questioning Techniques
All polygraph questioning techniques that aim at some form of standardization or reproducibility involve comparisons of physiological responses to questions of central interest for the investigation or screening (“relevant questions”) against physiological responses to other questions (“comparison questions”). Questioning techniques may differ in the nature of the comparison questions, the sequencing of questions, or the choice of which comparison questions in a sequence of questions will be compared with which relevant questions. They are also typically associated with particular approaches to conducting pretest interviews and interpreting polygraph charts. This appendix briefly describes some of the main polygraph questioning techniques and some of their variants.
All polygraph testing techniques normally begin with a pretest interview. The examinee and examiner discuss the test, test procedure, examinee’s medical history, and details of the test issues. The examiner also observes the behavior of the examinee and, in test formats that allow for discretion in question design, may gather information to be used in choosing comparison questions for the test. Depending on the complexity of the case, examiner-examinee interactions, and testing technique, the pretest interview may last from 30 minutes to 2 hours or longer (Krapohl and Sturm, 2001).
As its name implies, the relevant-irrelevant test format compares examinee responses to relevant and irrelevant questions. A relevant question is one that deals with the real issue of concern to the investigation. These questions include asking whether the examinee perpetrated the target act or knows who did it and perhaps questions about particular pieces of evidence that would incriminate the guilty person. An irrelevant question is one designed to provoke no emotion (e.g., “Is today Friday?). Irrelevant questions are typically placed in the first position of a question list because the physiological responses that follow the presentation of the first question are presumed to have no diagnostic value; they are also placed at other points in the question sequence. Guilty examinees are expected to show stronger reactions to relevant than to irrelevant questions; innocent examinees are expected to react similarly to both question types.
The relevant-irrelevant test format was the first widely used polygraph testing format and was long the dominant format. The format was originally used in criminal testing. Currently, it is also used in multiple-issue screening applications, for example, at the U.S. National Security Agency.
Relevant-irrelevant polygraph tests are not normally standardized for question selection or for interpretation. Examiners typically interpret the test results globally by inspecting the charts to see whether or not there is a pattern of stronger responses to relevant questions. The lack of standard procedures for administration and scoring makes the relevant-irrelevant test unsuitable for scientific evaluation. It is not possible to support general conclusions about its accuracy because the procedure can vary uncontrollably across examiners and examinations. Polygraph researchers generally consider the test outmoded. For example, Raskin and Honts (2002:5) conclude that the relevant-irrelevant test “does not satisfy the basic requirements of a psychophysiological test and should not be used.”
COMPARISON QUESTION (CONTROL QUESTION) TEST
Comparison question tests (also called control question tests) compare examinees’ responses to relevant questions to their responses to other questions that are believed to elicit physiological reactions from innocent examinees. Relevant questions are defined as in the relevant-irrelevant test. Comparison questions ask about general undesirable acts, sometimes of the type of an event under investigation. For example, in a burglary investigation, one comparison question might be “Have you
ever stolen anything?” In probable-lie comparison question tests, the instructions are designed to induce innocent people to answer in the negative, even though most are lying. Innocent examinees are expected to experience concern about these answers that shows in their physiological responses. In directed-lie tests, examinees are instructed to respond negatively and untruthfully to comparison questions (e.g., “During the first 20 years of your life, did you ever tell even one lie?”). In both forms of test, the expectation is that innocent examinees will react more strongly to the comparison questions, and guilty examinees will react more strongly to relevant questions.
Comparison question tests are widely applicable and are used both in specific-incident investigation and in screening. Some of the varieties of comparison question tests are described very briefly below. They vary in question selection, test construction, test scoring and interpretation, and other characteristics not discussed here (see Raskin and Honts, 2002, for more detail).
Reid Comparison Question Test
The Reid comparison question test, also known as the modified general question test, was the earliest form of comparison question test. It includes probable-lie comparison questions and is interpreted by the examiner’s global evaluation of the charts, combined with other observations made during the examination. Other characteristics of the test include a discussion of the examinee’s moral values during the test procedure and the use of a “stimulation” test between the first and second presentations of the questions (see Reid and Inbau  or Raskin and Honts  for more detail).
Zone Comparison Test
The zone comparison test, which was developed by Backster (1963), is named for the three “zones” or blocks of time during the test: the relevant questions (called the red zone), the probable-lie comparison questions (the green zone), and other questions (the black zone). Black zone questions are included to uncover examinee concerns about an issue outside of the scope of the red and green zones, such as involvement in another crime. Each zone is presumed to be threatening to someone; however, depending on the examinee’s mental set, it is anticipated that one particular zone is more threatening than are the other two (information from Donald Krapohl, U.S. Department of Defense Polygraph Institute, private communication, October 5, 2001). This was the first comparison question test to incorporate a numerical scoring system. It used a seven-point
rating scale applied to each physiological measure for each relevant question on the test.
Utah Probable-Lie Test
The Utah probable-lie test, developed by Raskin and colleagues (Raskin and Honts, 2002) is constructed with question modules, typically consisting of irrelevant, probable-lie comparison, and relevant questions. Examiners are instructed to conduct the test, including the pretest interview, in the low-key manner of a psychological interview rather than in the confrontational manner of an interrogation that is common in some other questioning formats: “It is critical that the examiner’s demeanor and behavior be professional and objective” (Raskin and Honts, 2002:18). Attention is paid to going over the questions with the examinee carefully during the pretest period. Charts are scored on a numerical scale that is a modification of the one developed for the zone comparison test. Computer interpretation programs have also been developed for this test.
Utah Directed-Lie Test
The Utah directed-lie test was developed to address some problems that were associated with the Utah probable-lie test, including the perceived need for highly skilled examiners, problems of standardizing the questions, and the possibility that examinees may misunderstand the purpose of the probable-lie questions and therefore fail to respond as the theory presumes. The test is administered and scored like the probable-lie version. The comparison questions are like those in the Utah probable-lie test, except that the examinee is told that anyone who gives a negative answer would be lying and is then asked to give a negative answer.
Test of Espionage and Sabotage
The Test of Espionage and Sabotage is a directed-lie test that was developed at the U.S. Department of Defense Polygraph Institute and is used by some U.S. government agencies, including the U.S. Department of Energy, for security screening. A repeated series of relevant and di-rected-lie comparison questions is used to address multiple issues (espionage, sabotage, unauthorized foreign contacts, and unauthorized release of information). This test is scored by the conventional seven-position scoring system used in the Utah tests, with the total score being the sum across the three examination parameters for each question on all charts. Numerical thresholds are predefined for judging whether or not a test indicates a significant response that might indicate deception or is incon-
clusive. A judgment of a significant response is normally followed by further questioning and possibly further testing with single-issue format polygraph tests.
The stimulation test, sometimes called the stim test or acquaintance test, is used by examiners in some test formats either during the pretest or between charts. Examinees are presented with a question set of very similar items and directed to lie about one. The examinee may be asked to pick one of several playing cards (card test) or to pick a number between three and seven (numbers test), and then to deny having picked each of the cards or numbers while connected to the polygraph machine. The main purpose of the procedure is to induce or strengthen in examinees the expectation that the polygraph can accurately determine the truthfulness of their answers.
CONCEALED INFORMATION TEST
Concealed information tests (more often called guilty knowledge or concealed knowledge tests) present examinees with sets of very similar items, much in the manner of stimulation tests, except that the similar items include one true and several (usually, four) false details of some aspect of an incident under investigation that has not been publicized, so that the true answer would be known only to the investigators and to those present at the incident. In a burglary, examinees might be asked about several possible points of entry into the house, one of which the burglar actually used. (For more detail about question construction and administration of concealed information tests, see Nakayama .) When an examinee is asked whether he or she used each of these routes, the answer is expected to be negative regardless of the examinee’s innocence or guilt. Guilty examinees are expected to reveal their concealed knowledge by responding more strongly to the true item than to the others.
Concealed information tests are applicable only under restricted conditions: when there is a specific incident, activity, or thing that can be the subject of questioning and when there are several relevant details that are known only to investigators and those present at the incident. Thus, these tests are not applicable in typical screening situations in which the only possible relevant questions concern generic events, such as unspecified acts of espionage that may or may not have occurred.
The peak-of-tension test is similar in format to concealed information tests, but is distinct because questions are asked in an easily recognized order (e.g., “Was the amount of stolen money $1,000? $2,000? $3,000?” etc.). A guilty examinee is expected to show a pattern of responsiveness that increases as the correct alternative approaches in the question sequence and decreases when it has passed. Stimulation tests often have this format. In a known-solution peak-of-tension test, the examiner knows which alternative is the one truly connected to the incident and evaluates the examinee’s pattern of responses for evidence of involvement in the incident. It is also possible to use the peak-of-tension test in a searching mode when the examiner does not know which answer is connected to the event but wants to use the test for help in an investigation. It is assumed that the pattern of a guilty person’s autonomic responses will reveal the correct answer.
Backster, C. 1963 The Backster chart reliability rating method. Law and Order 1:63-64.
Krapohl, D.J., and S.H. Sturm 2001 Terminology Reference for the Science of Psychophysiological Detection of Deception, updated from 1997 book by the American Polygraph Association.
Nakayama, M. 2002 Practical use of the concealed information test for criminal investigation in Japan. Pp. 49-86 in M. Kleiner, ed. Handbook of Polygraph Testing. San Diego, CA: Academic Press.
Raskin, D.C., and C.R. Honts 2002 The comparison question test. Pp. 1-47 in Handbook of Polygraph Testing, M. Kleiner, ed. San Diego, CA: Academic Press.
Reid, J.E., and F.E. Inbau 1977 Pp. 13-71 in Truth and Deception: The Polygraph (“Lie-Detector”) Technique. 2nd ed. Baltimore, MD: The Williams & Wilkins Company.