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Chapter 2
Varieties of Polygraph Testing and Uses
INTRODUCTION
Polygraph examinations have been likened topsychological testing (cf. 89, 92, 101). As such,polygraph testing is best described not in thesingular but, instead, as a series of tests. Thesetests are designed to assess truthfulness and deceptionin situations that range from screening jobapplicants to investigations of specific criminalincidents. Polygraph examiners, employed bothwithin and outside Government agencies, use avariety of polygraph testing techniques, each ofwhich has a somewhat different underlying logicand demonstrated validity.The choice of polygraph technique dependsprimarily on the circ*mstances under which thepolygraph is being used. The test of a subject whois suspected of a specific criminal activity typicallyinvolves application of a different polygraph techniquethan the examination of a prospective Governmentemployee. Some variation in techniqueis also related to examiners' training, but such differencesprobably affect the way in which a techniqueis employed rather than which techniqueis used. A description of the instrument used inpolygraph testing and an analysis of the types oftest situations and polygraph techniques are presentedbelow.
POLYGRAPH INSTRUMENT
Although there are numerous variations in testingprocedures, the polygraph instrument itselfis fairly standard. The polygraph measures several,usually three, physiological indicators ofarousal. Changes in physiological arousal exhibitedin response to a set of questions are taken toindicate deception or truthfulness, The polygraphinstrument, it should be noted, is not a "lie detector"per se; i.e., it does not indicate directlywhether a subject is being deceptive or truthful.There is no known physiological response that isunique to deception (108,122,123). Instead, a polygraphexaminer obtains a subject's responses toa carefully structured set of questions, and basedon the pattern of arousal responses, infers the subject'sveracity. This assessment has been called the"diagnosis" of truthfulness or deception (139).In actual field testing, subjects' physiologicalresponses are measured by a three- or four-channelpolygraph machine that records responses ona moving chart. Usually, three different types ofphysiological responses are measured. The rateand depth of respiration is measured by pneumographsstrapped around the chest and the abdomen.A blood pressure cuff (sphygmomanometer)placed around the bicep is used to measure cardiovascularactivity. In modern polygraph instruments,sphygmomanometer readings are electronicallyenhanced so as to permit lower pressure inthe cuff. The electrodermal response (EDR), ameasure of perspiration, requires electrodes attachedto the fingertips. This has also been referredto as galvanic skin response (GSR) or skinconductance response (SCR). Each of these physiologicalassessments has been shown to be relatedto physiological arousal (36). There is some literatureto suggest that one or more of the physiologicalchannels (EDR, in particular) is most sensitive(e. g., 123). Actual field testing, however,almost always involves measurement of all threetypes of responses.
TYPES OF TESTING PROCEDURES
A polygraph examination normally takes anywherefrom 1 to 3 hours, although shorter orlonger tests may result in a variety of circ*mstances.The length of an examination depends onthe purpose of the examination, as well as the subject'sattitude and a number of other factors. Examinationsmay be very short because a subject"confesses" or may be lengthy when an examinerseeks to resolve an inconsistent or inconclusivepattern of responses. The examination can be dividedinto at least three components: pretest interview;question procedure; and post-test interview.The actual questioning aspect of the examination,which may be repeated three or fourtimes, lasts no longer than a few minutes for eachquestion set (limited, in some cases, because theblood pressure cuff can be inflated for only 10 to12 minutes without causing the subject undue discomfort).Each aspect of a polygraph test isdescribed below in detail. Unless specificallynoted, generally used polygraph procedures aredescribed, Federal Government procedures areoften different and, where important such differencesare noted.The Pretest Interview
The pretest interview has been considered anindispensable component of the polygraph examination(121,139,194). The importance of thepretest is not only in its role to provide subjectswith information about the examination and toinform them of their legal rights, but also in itsability to generate the psychological climate considerednecessary for a valid polygraph test. Animportant purpose of the interview is to persuadea subject that the examination is professionallyconducted and that any deception attempted "willbe very obvious to the examiner" (20). Such instructions,it is thought, place truthful subjects atease and increase anxiety in subjects who intendto be deceptive. Persuading subjects about the effectivenessof the examination should sharpen differencesbetween deceptive and nondeceptive subjectsin their reactions to questions about a particularincident.
The pretest also allows the examiner to assessthe effect of special conditions or circ*mstanceswhich might affect physiological responsiveness.Thus, for example, subjects are typically queriedabout medical problems and use of drugs thatcould influence autonomic responding. Such assessmentsare usually made without collecting"hard" data, such as blood samples.
Consent Procedures
Depending on which polygraph method is employed,as well as the subject's attitude and thesituation under investigation, pretest interviewsmay take from 20 to 90 minutes (20,27). One aspectof the pretest interview involves obtainingthe subject's consent to be examined. Consent proceduresvary depending on the nature of the interview,most importantly between criminal orpreemployment polygraph tests. According toBarland and Raskin (20), a typical polygraph examinationconducted as part of a criminal investigationrequires that the examiner advise the examineeof his or her Miranda rights (or rightsunder the Uniform Code of Military Justice). Thesubject is also told that the polygraph examinationis voluntary. Subjects should also be informedwhether or not the examination will beobserved from outside the room or recorded.These disclosures are usually included in a writtenform which the subject is asked to sign. Accordingto Reid and Inbau (139), criminal suspectsmay already have been informed of their Mirandarights and been asked to sign a consent formbefore coming to the examination room.
Applicants for employment need not be advisedof their right to speak with an attorney but may,depending on local laws, need to be advised aboutthe voluntarism of the examination. In the caseof such employment-related tests, along with aprovision concerning voluntary consent, subjectswill be told how the results of the examinationwill be used. Thus, for example, they maybe toldthat a copy of the test results will be provided tothe sponsor of the exam, that the subject has aright to obtain a copy of the test results, that thesubject will not be asked questions concerningsuch areas as political activities, union affiliations,racial or religious beliefs, or sexual activities unlessthese areas are specifically related to the issueunder investigation (37).
Examples of consent forms used in criminal investigationsby Federal agencies are shown in appendixA. The contents of Federal consent formsvary somewhat by agency, although all requirethat the subject "voluntarily" consent to the examination.Some agencies (e. g., Department ofthe Treasury (186)) indicate that the subject hasthe right to stop the examination at any time. Althoughthe National Security Agency (NSA) reportsthat the full cooperation of the subject "isessential or the results will be inconclusive, " NSAalso reports (see app. B) that the polygraph examinationis part of the Agency's security processing,and that failure to complete processing (whichincludes polygraph testing) may result in failureto be accepted for employment. As discussed morefully below (see Current Federal GovernmentUse), NSA conducts polygraph examinations primarilyin the context of preemployment and periodicsecurity screening; most other agencies conductpolygraph examinations as part of specific-incidentcriminal investigations.
The remainder of the pretest interview alsovaries. In the method taught to Federal examinersat the U.S. Army Military Police School(USAMPS), * the interview focuses on questionsabout the subject's background: employment,family, education, health, and any previous legalproblems (20). The examiner aims to learn enoughto assess the subject's readiness for the examinationand to prepare anxiety-provoking controlquestions, if they are to be used. The polygraphexaminer then explains the polygraph techniqueto the subject and queries the subject in detailabout the incident being investigated.
- *The USAMPS provides polygraph examiner training for almost all Federal Government polygraph examiners, with the except ion of CIA and NSA examiners.
Another form of the pretest interview advocatedby Reid (founder of the Reid College of LieDetection) in criminal investigations makes useof a structured series of questions and deempha-sizes gathering biographical data (77,139). Questionsdeal with matters such as the subject's suspicionsabout who committed the crime and thesubject's feelings about the test. Questions are intendedto provoke so-called "behavioral symptoms"(139) that are believed to be indicators ofdeception. These symptoms include evasivenessin answering, or complaints that one's physicaldisabilities will invalidate the recordings. Whenan examiner who uses the Reid method latermakes an assessment of truthfulness, this informationis used to supplement the data gatheredfrom the physiological measures.
Whatever the format of the pretest interview,if control questions are to be used in the test, thelast part of the interview will be used to designsuch questions and review them with the subject.In this phase, biographical and behavioral informationcollected earlier becomes essential. The informationpermits the examiner to tailor controlquestions to the individual subject. The processof designing control questions is complex and isdiscussed further in the section below which describesthe control question technique (CQT).
Testing Procedure
Actual testing procedures have been describedin detail by Barland and Raskin (20) and Reidand Inbau (139). Polygraph measuring devices,including pneumographs, a sphygmomanometer,and electrodes, are placed on the subject eitherduring the pretest interview or at its conclusion.After the end of the pretest interview, the sphygmomanometeris inflated, and the recording ofresponses begins. A short period, of about 10 to15 seconds, is used to observe initial respiratorycycles (baseline) and to allow any initial responseto fade; then, the examiner asks the first question.Between each question, the examiner waits about15 to 20 seconds until the response to the last questionis finished and physiological response is closerto baseline. The examiner notes on the chart whenthe exam begins, when questions are asked, andwhen it ends. Extraneous behavior that affects therecordings may also be noted. When questions forthe first chart end, the examiner deflates the cuff.
The examiner then inspects the chart and asksthe subject about his or her reaction to the questions.The usual purpose for obtaining subjects'reactions is to allow refinements in the questions.The questions are reviewed again, and, when necessary,further clarified. The examiner may thenadminister a stimulation test, designed to improvetest validity. The examiner will then continue totest and obtain two or three more charts in thesame way. The examiner may use other stimulationtests between charts, and different questioningtechniques (see below) to record differentcharts. Different questioning techniques may thenbe used based on information revealed by the subject.In most techniques, any new questions wouldbe discussed with the subject before being asked.The procedure in preemployment screening or inother personnel screening tests may differ.
Stimulation Tests
Polygraph examiners typically conduct what isknown as a "stimulation" or "stim" test, designedto further convince subjects of the accuracy of thepolygraph examination. Although not actually apart of the pretest, stimulation tests can be giveneither before the first actual set of test questionsor after the first chart has been recorded. Stimulationtests are intended to reassure truthful subjectsand provoke anxiety in deceptive subjects(cf. 15). Their effect should be to increase differentialresponsivity of deceptive and nondeceptivesubjects to different questions on the examination.Some research suggests stimulation tests increasethe validity of polygraph examinations (35,149).
The most common "stim" test is a "number"or "card" test. A subject is instructed to select,from a deck, a card that has a number, word, orsuit on the back, or to write a number within acertain range (50,57). Sometimes, the cards aresecretly marked or otherwise arranged so that theexaminer is sure to know the correct answer (139).Many polygraph examiners claim this is unnecessary,however, because the technique is accurateenough without use of such deception (cf. 123),and secret markings are not employed by Federalagencies. The examiner then may repeat a rangeof suits, numbers or a set of words, asking thesubject if each is the concealed item. The suit,number, or word that is actually the concealeditem is supposed to provoke the greatest physiologicalresponse. Often, the examiner will showthe subject the polygram (i.e., the actual chartrecordings) to further convince subjects of the instrument'sefficacy.
Types of Questions
The central element of any polygraph examinationis the test of subjects' responses to a set ofquestions or items within questions. How thesequestions are structured represents the principaldifference among polygraph techniques. There arefour different kinds of questions or items used inpolygraph testing, different combinations of questions(generally referred to as question techniques),and different applications for the varioustechniques. Distinctions among questions andtechniques are important. Only one type of questiontechnique in one application (CQT in criminalinvestigations) has been extensively researched(see chs. 4 and 5); and there are significant differencesbetween CQT and other techniques. Therange of questions, techniques, and applicationsis described more fully below.Questions
The kinds of questions that are used for polygraphtesting have been labeled relevant questions,control questions, irrelevant questions, andconcealed information or guilty knowledge questions.Basically, relevant questions are questionsabout the topic under investigation (a theft, druguse, contact with foreign agents). Suspects' responsesto relevant questions are of greatestinterest to polygraph examiners.
Control and irrelevant questions can begrouped together as questions used for purposesof comparison to relevant questions. It is importantto note, however, that the name one givesto a question may depend on the specific contextin which it is used. Thus, one cannot easily givean example of a relevant question or a controlquestion because in different situations and at differenttimes during an examination relevant questionsmay be used as control questions. Likewise,irrelevant questions may become relevant, dependingon a subject's response (201).
Relevant Questions
Functionally, relevant questions are questionsdirectly related to the focus of an investigation.In the investigation of a theft, for example, a relevantquestion might be "Did you steal thatmoney?" or even more specifically, "Did you take$750 from Jones' office?" Relevant questions canbe broader, however. In preemployment screeningand periodic or aperiodic screening, the areaof interest may be the subjects' entire background.Thus, there may be a series of relevant questions,such as "Have you ever been fired from a job?"or, "Have you stolen more than $50 in moneysin any one year from any of your employers?"(115). Intelligence agencies may ask broad questionsconcerning unauthorized contact with foreignintelligence agents or involvement in communistactivities. Questions in an intelligencescreening may also deal with areas which, potentially,may make an applicant susceptible toblackmail. It is important to note, however, thatwhen several relevant questions relating to differentissues are used, subjects are not expectedto exhibit physiological responses to all of them;the relevant questions that do not evoke responsesare used, after the fact, as a type of controlquestion.
To summarize, relevant questions are questionsabout the topic under investigation, but topics canbe very specific (Did you take $750 from Jones'office?) or cover a long period of time and a varietyof acts (Have you ever stolen money from anemployer? Have you ever had unauthorized contactwith a foreign agent?). It is not clear whateffect, if any, the breadth of a relevant questionhas on polygraph results, nor has there been anyresearch done on this issue. As is discussed furtherin chapters 4 and 5, the preponderance ofresearch evidence concerns the use of relevantquestions to evoke reactions to specific acts.
Comparison Questions
In contrast to relevant questions, which concernissues of direct interest to the examiner, controland irrelevant questions are used for purposesof comparison. As noted above, there is noknown physiological response unique to lying.Thus, a polygraph examination could not consistmerely of relevant questions. If only relevantitems were used, an examiner would not be ableto establish the actual reason for the response.There are a number of reasons, other than fearof detection (or another hypothetically lying relatedreaction (19)) for a subject to become physiologicallyaroused during the presentation of relevantquestions (48,108,136, 194). Even with theaddition of nonrelevant comparison items, it isnecessary to run several polygraph charts usingthe same questions (though, perhaps in differentorder) to be sure that reactions are consistent. Ifseveral charts are not run, a subject's responsescould be attributed to surprise, physical movement,or some reasons for concern other than alying-related cause (203). On the other hand, theadministration of several charts could theoreticallyjust repeat the initial situation leading to thephysiological response if the cause were not a randomone (e.g., presence at the scene, knowledgeof the incident, concern over being falsely identified).Thus, the essence of polygraph testing isthe comparison of responses to the relevant questionswith responses to nonrelevant questions,which have been labeled control questions andirrelevant questions.
Control Questions
Control questions, then, are used for purposesof comparison. Essentially, truthful subjects arebelieved by polygraph examiners to be more concerned(and, thus, more physiologically aroused)about control than relevant questions. The responsesto both control and relevant questions arecompared. However, control questions, like relevantquestions, vary in breadth and type. Onetype of control question concerns what is hypothesizedto be the same kind of issue that is underinvestigation at the time of examination. For example,a control question for "Did you take the$750 from Jones' office?" might be "Other thanwhat you have told me [during the pretest interview],have you ever stolen anything in your life?"In an investigation of unauthorized disclosure ofclassified information, a control question mightbe "Have you ever betrayed anyone who trustedyou?" Subjects innocent of the crime under investigationare presumed to be more concernedabout having ever done anything of this sort (and,thus, being the "kind of person" who might havecommitted the crime under investigation). It istheorized that although guilty subjects will alsobe concerned about control questions, they willbe more concerned about and thus exhibit morephysiological reactions to relevant questions.
There are a number of views, however, aboutwhat distinguishes a control question from a relevantquestion. One distinction among controlquestions is whether a question is inclusive or exclusive.Inclusive control questions are questionswhich include the specific incident under investigation.An example of an inclusive control questionin an investigation of an internal theft wouldbe "Have you ever stolen money from an employer?"Exclusive control questions, on the otherhand, cover a period of time not including the incidentunder investigation. An example is, "Beforeage 18, did you ever take anything of value?"There is some controversy over how far back intime an exclusive control question must be set forthe subject to consider it psychologically separatefrom the incident under investigation and, thus,not a relevant question. Because inconclusive controlquestions may, from the suspect's perspective,include the act under investigation, somepolygraphers contend that they are really relevantquestions; i.e., they cannot be used for purposesof comparison. The Federal Government, for example,typically uses exclusive control questionsbecause it views inclusive controls as relevantquestions. Examiners from the private polygraphfirm of John E. Reid & Associates use both inclusiveand exclusive control questions.
Other kinds of nonrelevant questions other thanthose that cover the same kind of incident as theone under investigation, or which cover it in adifferent way, are also considered to be controlquestions. Thus, for example, "Have you ever fantasizedabout giving a document to a foreignagent?" is a type of control question used in someintelligence investigations. In some screening examinations,in which contact with a foreign agentis of primary concern (i. e., constitutes the relevantquestion), "Have you ever done anything forwhich you are now ashamed?" could be a controlquestion. When a different issue than susceptibilityto blackmail is under investigation, "Haveyou ever done anything for which you could beblackmailed?" can be used as a control question.It is noteworthy that in a different context, suchas a broader screening examination, these wouldbe considered relevant questions.
Control questions, then, are questions forwhich the responses are designed to be comparedto responses to relevant questions. In some screeningexaminations, relevant questions may functionas control questions after the fact. That is,if a relevant question produces a relatively mildphysiological response, it may be compared toother relevant questions that produce greater response.Most often, control questions are designedto be arousing for innocent subjects (i.e., thosewho are not being deceptive on the relevant questions),relative at least to relevant questions. Thisis usually the central point of control questions,and is central to the control question technique(CQT) discussed below.
Irrelevant Questions
Another type of question used, in part, for purposesof comparison to responses to relevant questionsis the socalled irrelevant question. Examplesof irrelevant questions commonly used in investigationsare; "Are you called [subject's name]?"or "Is today Tuesday?" Irrelevant questions arequestions which are believed to have no, or verylittle, emotional impact on a subject. Thus, suchquestions can be used as an indicator of a particularsubject's normal baseline level of arousal; nouniversal standard of physiological arousal canbe applied because individuals differ markedly.Irrelevant questions are hypothesized to serve purposesother than providing a physiological baseline(139). Perhaps most important, irrelevantquestions interspersed among relevant questionsare hypothesized to provide a type of rest periodfor the subject.
Concealed Information Questions
Questions about concealed information are thefourth type of question used in polygraph testing.Unlike control and relevant questions, which asksubjects whether they have committed a crime,concealed information items aim to detect informationabout a crime that only a guilty subjectwould have. Such information might include detailsabout the site of the crime or the means ofcommitting it, such as the type of murder weaponused. It is hypothesized that guilty subjects willexhibit a different physiological response to thecorrect (relevant) detail than to the incorrect details, but that innocent subjects will respond thesame to all the items. Different types of concealedinformation tests are described below (see ConcealedInformation Tests).
Summary
For any technique, deception is detected bycomparison of suspects' physiological responseson critical or "relevant" questions or items withtheir responses on noncritical (irrelevant or control)items. Greater physiological responses torelevant items than to noncritical (control, irrelevant)items are assumed to be indicative of deception.
Polygraph Question Techniques
Three types of question techniques combiningthe four question types are described below: therelevant/irrelevant (R/I) technique, the controlquestion technique (CQT), and concealed informationtechniques. Each of these test types tends tobe used for particular purposes; e.g., the R/I techniqueis used in the great majority of preemploy mentscreening interviews, while CQT is normallyused in criminal investigations. There have beenadaptations of these techniques for other uses,some of which are discussed below. Also, examinersmay combine different techniques in an investigation(see, e.g., 139). In general, R/I has thebroadest potential use while the concealed informationtechniques are the least applicable. Withineach category, particularly CQT, there is considerablevariability and several versions of eachtechnique are employed.Relevant/Irrelevant (R/I) Techniques
The R/I technique was the first standard methodof polygraph questioning. The method was developedby Marston (114), a psychologist and theoriginal proponent of polygraph examinations.An adaptation of this traditional technique is usedin most of the preemployment screening conductedin the United States.
However, the R/I technique as used by the FederalGovernment involves somewhat differenttypes of questions than the traditional R/I, andit must be explained separately. As currently usedby Federal examiners, the R/I relies on a type ofcontrol question, and is claimed to be a versionof the control question technique. The versionsdiscussed in this section are:
1. the traditional R/I;
2. the Federal version of the R/I; and
3. the R/I as used in typical preemploymentscreening tests.
There are numerous well-recognized problemswith the traditional R/I technique, at least fromthe perspective of psychologists who have evaluatedpolygraph test validity (cf. 108,126,136).First, the intent of the relevant and irrelevant questionsis transparent, which means that the relevantquestions are likely to be more arousing forthe truthful as well as the deceptive subjects. Second,questions in the R/I technique are not usuallyreviewed with the subjects before the test. A largerresponse to the relevant question may, thus, bedue to surprise or misunderstanding, as well asdeception. Third, as with any question technique,reactions may be flattened by drugs or by the generallyreduced responsivity of certain subjects(136). These effects are probably more difficultto detect with R/I than with other question techniques.
Because of these problems, the confidence onecan place in the R/I technique is limited (136). Asa consequence, the R/I technique is typically notused in the case of specific incident examinationsby either public or private examiners. It is usedalmost exclusively with employees in nonspecificinvestigations. The Federal Government occasionallyuses the traditional R/I and also a versionof the R/I which is claimed to function as a controlquestion test. The Federal Government versionof the technique is called the general questiontest (GQT). Like the Reid CQT (discussedbelow), it uses inclusive control questions, whichpertain to the subject's entire life, such that a completeanswer would also include the specific incident being investigated. Thus, with a questionlike, "Did you ever steal anything from a placewhere you worked?" the theft being investigatedwould in actuality be part of the answer, Technicallythese are seen as "relevant" questions,because they are pertinent to the incident in question.Yet they are claimed to function as controlquestions, because they are intended to provokea greater response in innocent subjects than questionsabout the misdeed provoke.
An adaptation of the R/I technique is the principalmethod of questioning used in preemploymentand periodic or aperiodic personnel screening.Unlike the questions used with other techniques,R/I questions need not focus on one specificwrongdoing (20,108). The examiner can,thus, use the method to assess any number ofissues for which the subject's veracity is to beevaluated.
In polygraph examinations used to screen employees,the polygraph examiner usually presentsa series of relevant questions, with several irrelevantquestions interspersed to provide a baseline.Most relevant questions ask about past behaviorthat might disqualify the subject from a job (e.g.,employee theft, drug use, fighting on the job, incurringa large debt). Some examinations may includequestions about a potential employee'sbackground or intentions regarding a job, for example,"Did you actually graduate from college?"(201) or "Are you seeking a job with this companyfor any reason other than legitimate employment?"(115). Listed below is an example of questionsfrom a preemployment screening protocolused by a commercial firm (115; also see 56,204).
Relevant questions:
- Did you tell the complete truth on your job application?
Have you deliberately withheld information from yourjob application?
Have you ever been fired from a job?
Are you seeking a permanent position with thiscompany?
Since the age of ( ) have you committed an undetectedcrime?
Since the age of ( ) have you been convicted of a crime?
During the past year, have you used marihuana (sic)more than ( ) per ( )?
Have you used any other narcotic illegally in the past( ) years?
Have you sold marihuana (sic) or other narcotics illegallyin the past ( ) years?
Have you ever stolen more than ($ ) worth of merchandisein any one year from any of your employers?
Have you even stolen more than ($ ) in moneys in anyone year from any of your employers?
Have you ever used a system to cheat one of your employers?
Have you ever had your driver's license suspended orrevoked?
Have you ever had any traffic citations in the past five(5) years?
Are you seeking a job with this company for anyreason other than legitimate employment?
Have you deliberately lied to any of these questions?
- In the last five years did you steal any merchandisefrom previous employers?
In the last five years did you steal any money fromprevious employers?
In the last ten years did you take part in or commitany serious crime?
Did you falsify any information on your application?
The Reid firm also uses what it regards as controlquestions in preemployment interviews. Controlquestions include, "Did you ever steal anythingin your life?" and "Did you lie to any ofthe questions you answered during the applicationprocess for this job?" It is not clear, however,how the Reid preemployment control questionsdiffer from the relevant questions. It seems reasonableto suppose that both truthful and non-truthfulsubjects (in terms of the relevant questions)may be just as concerned with the subjectmatter of the control questions as they are withthe relevant questions. It is also not clear whyemployers would be less concerned with the controlthan with the relevant questions.
In the R/I questioning technique, a diagnosisof truthfulness or deception indicated is made bycomparison of responses to each relevant questionwith the responses to the irrelevant questionsand the remaining set of relevant questions (orin the Reid, and Army examples, control questions).Presumably, an applicant will be deceptiveon no more than a few questions. These questionswill provoke a greater physiological responsethan the others, leading to further inquiries andan eventual diagnosis (56,204).
Other types of questions are used in somescreening examinations, such as questions aboutsexual practices or gambling. Such questions seekinformation about an applicant's character ratherthan his or her job performance and are consideredby some to be unduly invasive (173). In responseto this practice, ethical standards havebeen developed for use of the polygraph in preemploymentscreening (cf. 154), and some States(e.g., Illinois) prohibit their use. Preemploymentpolygraph examinations fall under the guidelinesfor employment interviewing of title VII of theEqual Employment Opportunity Commission,and so examiners are obliged to conduct the examinationsin a way that would not discriminateon the basis of sex, race, etc. (cf. 154). One centralprinciple of ethical standards is that relevantquestions be related to the job applied for.Whether questions meet this criterion depends onthe job; e.g., information about one's drivingrecord would be important in hiring a deliveryperson, but not in hiring a bank teller. Screeningapplicants for positions involving national securityapparently require questions about sexual behavior,drug use, and mental health as well asareas more directly related to national security(e.g., involvement in espionage). The range oftopic areas covered in national security pre-employmentscreening examinations by NSA isdiscussed below under Current Federal GovernmentUse.
In so-called periodic or aperiodic checking forinternal security purposes, employees are askedto submit to occasional polygraph examinations.These examinations can assess drug use, subjects'own or others' employee theft, and other mattersincluding job satisfaction and commitment. In thistype of examination, almost all of the questionsare relevant questions and apparent deception(arousal) in response to any of the items is explored.Examples of the kinds of questions usedin aperiodic screening in a supermarket (204),include:
- Are you relatively satisfied with this job now?
Do you, as far as you know at this time, intend to staywith this employer?
Have you ever intentionally underpriced or underweighedmerchandise?
Is there a particular person at your store that is responsiblefor damaging merchandise due to real carelessness,not caring or intentionally?
Control Question Technique (CQT)
The CQT is the most common technique usedin investigations of a specific issue. The CQT wasdeveloped to deal with some of the inherent problemsin the traditional R/I technique (139). Likethe R/I technique, it asks relevant questions aboutthe crime like "Did you steal the $750 from Jones'office?" As with R/I, the deceptive subject isassumed to produce a greater autonomic responseto the relevant than to other questions. But CQTalso adds control questions, which, as discussedbriefly above, are designed to provoke a greaterresponse in subjects who are innocent and truthfulabout the crime being investigated.
As discussed above, control questions are designedto be arousing for nondeceptive subjects.The questions are designed to cause innocent subjectsto be doubtful and concerned about whetherthey have actually told the truth or told a lie.These questions usually probe for past misdeedsof the same general nature as the crime being investigatedbut they are transgressions that poly grapherssuspect most people have "committed"or considered committing in some form (139). Anexample of a control question might be, "Beforethe age of 25, did you ever steal anything froma place you worked?" Control questions are designedto cover a long period of time, which maymake the subject even more doubtful about theveracity of answers provided.
Considerable attention in the pretest interviewis devoted to development of control questions(139). The process of developing control questions,reviewing them with the subject, and thenrefining them is designed to develop the most appropriatequestions, and to convince subjects toview control questions as seriously as relevantquestions. In addition, the pretest review is designedto get subjects either to be deceptive to controlquestions or at least to be concerned aboutthe accuracy of their recollections (20,37,91,139).It is considered crucial to produce in the subjectthe right psychological set in relation to the controlquestions. This set is then thought to lead subjectsto be more concerned about control questionsthan relevant questions, and so to respondmore to them physiologically. This difference betweenresponse to control and relevant questionsis then the basis for the diagnosis of deceptive ornondeceptive. Since the subject's psychological setis so crucial when control questions are used, differentialresponding to relevant or control questions(and ultimately, the validity of CQT), dependson the nature of the interaction betweenexaminer and subject. This is true regardless ofthe act in question, the particular CQT methodused, or the method of making assessments oftruthfulness or deception. Even the validity of anentirely computerized system of scoring and diagnosiswould depend on the nature of the interactionbetween examiner and subject. In this sense,CQT examinations, as the technology to conductpolygraph tests now stands, always require examinersto make important judgments about and interventionsin their interaction with subjects.
The polygraph examiner does not tell the subjectthat there is a distinction between the twotypes of questions (control and relevant). Controlquestions are described as intending to determineif the subject is the "type of person" whowould commit a crime such as the one being investigated(136). The examiner stresses that thesubject must be able to answer the questions completelywith a simple "yes" or "no" answer, thatthe polygraph will record any confusion, misgivings,or doubts, and that the subject should discussany troublesome questions with the examiner (20).Thus, the situation is set up such that the subjectis persuaded that the examiner wants the truth.In reality, however, the examiner wants the subjectto experience considerable doubt about hisor her truthfulness or even to be intentionallydeceptive. According to Raskin (91), "Controlquestions are intentionally vague and extremelydifficult to answer truthfully with an unqualifiedNo'."
To produce the final version of a control question,the examiner begins by asking the subjecta broad version of the question used in the pretestinterview. Thus, for example, the question mightbe structured, "Did you ever steal anything inyour life?" At this point, different polygraph examinersuse slightly different methods to handlethe discussion of past wrongdoing in response tothe control questions asked during the pretest interview.In the USAMPS method (91), if the subjectconfesses to a small transgression in the past(e.g., taking home pencils from work), the examinerwill dismiss it as of no consequence. For othermisdeeds, the examiner will rephrase the controlquestions to rule them out (e.g., "Other than whatwe have discussed, did you ever steal anythingin your life?"). The examiner will actively interveneto prevent subjects from unburdening toomuch of their anxiety over their past wrongs withthe intention of keeping them concerned duringthe actual polygraph testing. Any troublesomepast transgressions the subject brings up are excluded(by such phrases as "Other than what wehave discussed, . . . ?") so the subject is alwaysbrought to the point at which he or she answers"No" to the control question. The control questionis then ready to be used in actual testing.
The Reid method varies from the Federal methodin some ways (139). If the subject does not admitto a past wrongdoing, the examiner mayprobe until the subject admits to one, even a crimeas small as stealing pocket change from a relativeduring childhood. Such transgressions are thenruled out by adding the kind of exclusionaryphrase discussed above (i. e., "Other than whatwe have discussed, . . . ?"). However, as in theUSAMPS method, it is assumed at this point thatthe subject is either concealing other misdeeds oris worried that there are others he or she hasoverlooked (139). This worry has been heightenedbecause of the examiner's emphasis on learningthe truth to "ascertain" that the subject is not thekind of person that could have committed thecrime referred to in the relevant questions. Inaddition to relevant and control questions, irrelevantquestions are included during the actual interviewin order to provide a baseline of physiologicalresponsiveness.
Several versions of CQT are regularly employedand adaptations depend both on the trainingof the examiners and the testing situation. TheReid version can include relevant questions aboutseveral aspects of the crime (139). For example,one chart could include questions about breakinginto an office, stealing a check, and thencashing it. Examiners who use Reid's CQT makea global comparison between the responses to therelevant and the responses to the control questions.They also note the subject's behaviorthroughout the interview (as discussed above, theReid technique includes a series of questions inthe pretest interview designed to provoke certain"behavioral symptoms" in deceptive subjects).The examiner uses the global comparison of polygraphresponses supplemented by informationabout the behavior of the subject to make a judgmentof the subject's veracity. An example of aReid control question sequence, excluding thepretest behavior provoking items, follows (139):
- 1. Do they call you "Red?" (where the pretest interviewhad disclosed he is generally called "Red.")
2. Are you over 21 years of age? (or reference is madeto some other age unquestionably but reasonably,and not ridiculously, below that of the subject. )
3. Last Saturday night did you shoot John Jones?
4. Are you in Chicago (or other city) now?
5. Did you kill John Jones?
6. Besides what you told about, did you ever stealanything else?
7. Did you ever go to school?
8. Did you steal John Jones' watch last Saturdaynight?
9. Do you know who shot John Jones?
10. Did you ever steal anything from a place whereyou worked?
A version of ZOC is used by Federal polygraphexaminers. The Federal version differs from theBackster ZOC in that it may ask about severalaspects of the crime in one chart. Relevant questionsare asked about primary involvement (e. g.,"Did you steal _____?"), secondary involvement(e. g., "Did you help steal _____?"),and so called evidence connecting (e. g., "Do youknow where any of that money is now?"). In additionto relevant, control, and irrelevant questions,the Government ZOC test contains a versionof the peak of tension test (see below), and"symptomatic" questions of two types. One typeof symptomatic question (e. g., "DO you understandthat I'm not going to ask any trick or surprisequestions?") is designed to test whether theexaminee trusts the examiner's word that no surprisequestions will be asked. A large response issymptomatic of distrust. A second type of symptomaticquestion (e.g., "Is there something elseyou are afraid I will ask you a question about,even though I have told you I would not?") is totest whether there is some other issue the examineeis concerned about (e. g., another crime) that maybe absorbing his or her arousal.
Other versions of CQT or related techniquesare also used by Federal agency examiners. One,the modified general question test (MGQT), resemblesthe Reid CQT with the following differences:1) only the polygraph charts are used tomake determinations of truth and deception andglobal evaluations using inferences about behaviorare dispensed with; 2) charts are numericallyscored; 3) control questions exclusively concerna time and place separate from the time and placeof the crime under investigation, with the intentionof clearly separating responses related to thecrime and the control question; and 4) the contentof control questions is always related to thecrime under investigation, i.e., control questionsabout theft are used to investigate a theft, control questions about assault are used to investigateassault, etc. Presumably, when unauthorized disclosuresare at issue, control questions would concernsome sort of unauthorized disclosures in thepast.
To summarize, there are a number of controlquestion techniques, the most commonly used beingthe Reid CQT, MGQT, and ZOC. Despite differencesamong them, they share the same premiseand underlying rationale. Use of each of the controlquestion procedures relies on subjects' notknowing when they are being asked the relevantand control questions. If they know which questionsare more important for scoring purposesthey may be able to make anticipatory responseswhich could invalidate their charts (see ch. 6).
Concealed Information Tests
Another polygraph questioning techniqueworks on an entirely different premise than eitherCQT or R/I. Instead of detecting deception abouthaving committed a crime per se, concealed informationtests aim to detect whether a suspecthas information about a crime that only a guiltysubject would have or, in some cases (e. g., theactual amount of money embezzled) to detect theinformation itself. Such information might includedetails about the site of the crime or the meansof committing it (e. g., the type of murder weaponused). Raskin (136) has aptly described these as"concealed information tests." Concealed informationtests take two forms: the peak of tension(POT) test and the guilty knowledge test (GKT).
POT was developed by Keeler (cf. 69) and haslong been used in criminal investigations. ThePOT test uses a set of five to nine nearly identical"yes or no" questions asking if the subjectknows about a particular detail related to a crime.The detail may be a type of object used, or thecolor of an item. One question actually includesthe relevant detail, while the others include plausiblebut false details of a parallel nature. The questionsand the sequence in which they are askedare reviewed with the subject in the pretest interview.The subject is usually instructed to answer"no" to each question. The question with the truedetail is usually presented in the middle of thesequence, so that the subject's physiological reactions will increase up to the critical question,where they will reach a peak, hence the name,and fall back down again. The card and numberstimulation tests discussed above are actually examplesof POT. Barland and Raskin (20) providea hypothetical example of a POT in a criminalcase:
- 1. Regarding the color of the stolen car, do you knowit was yellow?
2. Do you know it was black?
3. Do you know it was green?
4. Do you know it was blue?
5. Do you know it was red?
6. Do you know it was white?
7. Do you know it was brown?
The GKT, described initially by Lykken (105,106) works in much the same way as POT. GKT,however, often includes a larger set of questions,and the questions may be of the multiplechoicetype rather than the "yes or no" type. Also, studiesinvestigating GKT have only used the electrodermalresponse, while POT tests have employedstandard three-channel polygraph recordings. Anexample of two questions from a GKT used in alaboratory study by Lykken (105) is listed below:
- 1. If you are the thief, you will know where the deskwas located in the office in which the theft occurred.Was it (a) on the left, (b) in front, or (c)on the right?
2. The thief hid what he had stolen. Where did he hideit? Was it (a) in the men's room, (b) on the coatrack, (c) in the office, (d) on the windowsill, or (e)in the locker?
Concealed information tests have, according toseveral reviewers (e.g., 108,136), other importantlimitations. One problem is that they may not bewidely applicable. Knowledge about an incidentmay not differentiate between a guilty and innocentperson where, for instance, a suspect is presentat the scene of a crime but claims that someoneelse is responsible (108,136). Furthermore,concealed information tests require investigatorsto gather information that is not always possibleto obtain, or must be disclosed to suspects in otherparts of the investigation (136). In some cases,publicity about the details of a crime eliminatesthe possibility of a concealed information test,since the information is public knowledge (136).
POST-TEST INTERVIEW
Interspersed among test questioning and measurementof physiological responses are a numberof opportunities for examiners to discuss the testwith the subject. At each occasion, the examinerreviews the questions, and, depending on the responses,questions subjects about their responses.At the end of the examination, the examiner willmake an assessment of whether a subject is beingdeceptive or nondeceptive. In some methods, e.g.,Reid's (139), the assessment is a global one employingbehavioral as well as polygraph data. Butthe USAMPS Backster's ZOC and other methodsattempt to rely strictly on polygraph chart interpretation(11,20). In examinations conducted bythe Federal Government, the final official determinationis made after supervisory review of polygraphcharts. If the subject is judged to be deceptiveduring the examination, the examiner will attemptto elicit a confession. Usually, this is notdone directly but is couched in terms of providingthe subject with an opportunity to clarify/explainthe responses and differences obtained.USES OF POLYGRAPH TESTING
As has been implied in much of the above discussion,polygraph examinations are used for avariety of purposes. The goal of all such applicationsof the polygraph is the detection of deceptionor substantiation of truthfulness. The natureof the test situation, however, leads to importantdifferences in the way a polygraph examinationis conducted. Unfortunately, the published researchliterature deals almost exclusively with theuse of the polygraph by police and military examinersfor criminal investigations. The researchliterature on a number of important uses of polygraph testing, such as for national security purposesand for employment screening, is extremelylimited.Current Use
The majority of uses of polygraph testing appearto be on behalf of private employers, the nextgreatest number are in the context of local criminaljustice investigations, and the remainder are doneby the Federal Government. Of greatest concernfor the present analysis are the numbers and typesof examinations currently conducted by agenciesof the Federal Government. This section will devotemost attention to such uses, although localgovernment and private use are briefly discussedin order to place Federal use in context.
Current Federal Government Use
In order to assess the extent of polygraph useamong Federal agencies, the Office of TechnologyAssessment (OTA) conducted a survey of Governmentuse during May 1983. The request forinformation was sent to the Departments ofDefense (DOD), State, Justice, Treasury, the U.S.Postal Service, and the Central Intelligence Agency(CIA), all of which were believed to employpolygraph examinations. Information was requestedabout the number of examinations, purposes,and results, as well as about research conductedand/or planned (see app. B). At the timeof this technical memorandum, all agencies exceptingCIA had provided written responses tothe request for information about the number andtype of polygraph examinations that have beenadministered.
CIA declined to respond because of the classifiednature of the information. However, somedata about CIA's use for background investigationswere reported in a 1980 study (165). Thenumber of polygraph examinations are summarizedin table 1. Table 1 indicates that Federalagencies reported administering a total of 22,597polygraph examinations in fiscal year 1982. Asshown in appendix B, about half of these werein the context of criminal investigations. Polygraphexaminations are also reported to be usedfor intelligence and counterintelligence investigations(some (NSA) at aperiodic intervals), andpreemployment screening. The largest single numberof polygraph examinations conducted in 1982were conducted by NSA, a component of DOD,primarily for preemployment screening. Thesenumbers can be compared to previous surveysconducted in 1963, when Federal agencies, excludingNSA and CIA, conducted 19,796 polygraphexaminations, and 1973, when 6,946 examinations(including 3,081 by NSA) were conducted.
Table 1Polygraph Examinations Conducted by Federal Agencies, 1982Agency TotalDepartment of Defense:Army Criminal Investigation Command3,731Army, Intelligence Command279Navy 1,337Air Force 3,019Marines263National Security Agency9,672Department of Justice:Federal Bureau of Investigation2,463Drug Enforcement Agency211Department of the Treasury:Secret Service714Bureau of Alcohol Tobacco and Firearms 256U.S. Postal Service652Central Intelligence Agencyn.a. [c]Totals22,597a. Data were also reported for fiscal years 1980, 1981, and, in some cases yearto date 1983. See app. B for complete report. b. The US. Customs Service (Department of the Treasury), Department of Healthand Human Services, and Tennessee Valley Authority conduct a limited butunknown number of polygraph examinations c. classified or partly classified.SOURCE: Office of Technology AssessmentAs shown in appendix B, NSA reports that ituses primarily the R/I technique. NSA reportsthat counterintelligence-type screening examinations-- i.e., tests given to NSA (or affiliated) personnelwho already have access to classified information--would have relevant questions on thetopics of involvement in espionage or sabotageagainst the United States; knowledge of others involvedin espionage or sabotage against the UnitedStates; involvement in giving or selling classifiedmaterials to unauthorized persons; knowledge ofothers giving or selling classified material to unauthorizedpersons; and unauthorized contactwith representatives of a foreign government(187). Examinations that are given to applicantsfor employment and contractors who are applyingfor access to Sensitive Compartmented Information(SCI) consist of questions about the topicscovered in counterintelligence-type aperiodicscreenings (phrased as "Do you plan to commit.. . ?") as well as questions about a broaderrange of issues: involvement in communist, fascist,or terrorist activity; commission of a seriouscrime; involvement in adult hom*osexual activity;involvement with illegal drugs or narcotics;deliberate falsification of security processingforms; treatment for a serious nervous or mentalproblem (187). According to NSA, the scope ofspecific issue examinations is limited to questionsthat are relevant to the issue to be resolved. Presumably, specific issue examinations would beconducted using the control question technique.
Current DOD regulations also allow the use ofpolygraph examinations to investigate situationsin which credible derogatory information aboutan individual with clearance is provided to officials.The frequency of this type of investigation,however, was not reported, Prior to thePresident's National Security Decision Directiveof March 11, 1983, use of the polygraph in personnelinvestigations of competitive service applicantsand appointees to competitive servicepositions was limited to executive agencies withhighly sensitive intelligence or counterintelligencemissions affecting the national security (e. g., amission approaching the sensitivity of that of CIA;see 188). Approval to use the polygraph could begranted for only 1-year periods. Refusal to consentto a polygraph could not be made a part ofan applicant or appointee's personnel file. Seechapter 3 for a description of proposed changesin Federal use of polygraph testing.
Non-Federal Government Use
Outside the Federal Government, polygraph examinationsare administered as part of criminalinvestigations, as well as preemployment screeningand periodic screening of employees for purposesof controlling internal crime and recommendingpromotions. Less frequent uses includeexaminations in such situations as paternity investigationsand workers' compensation cases. Ithas been estimated that over a million polygraphexaminations are given a year (107), 300,000 ofthem for employment purposes alone (128).
Both private and police polygraphers use polygraphexaminations in the process of criminalinvestigations (see 136). In some cases (most typically,rape and kidnapping cases, but also, forexample, investigations of improper or illegal conductby public officials (177)), witnesses and victimswhose veracity is in doubt are asked to takea polygraph examination. Suspects who claim innocencemay be asked by their defense attorneysor the prosecution to support their claim by takinga polygraph examination. In such cases, prosecutorsand defense attorneys may make informalagreements to drop the charges if the polygraphexamination indicates no deception. Or, theprosecution and the defense may formally stipulatethat if deception is indicated, results of thepolygraph examination will be admissible at trial.In some cases (New Mexico, Massachusetts, andthe 9th Federal Circuit Court of Appeals (8,136,156,157)) polygraph evidence has been admittedover objection. Polygraph evidence is also usedoccasionally in postconviction proceedings suchas sentencing and motions for a new trial (136).In polygraph examinations as part of criminal investigations,some version of the control questiontechnique is typically used.
The use of the polygraph examination by employersis reported to be widespread (144). Althoughit is illegal to ask employees to take anexamination in 19 States and the District of Columbia,it is legal to do so in 31 States (8,156,157).Polygraph examinations are used most commonlyin commercial banking, investment banking, andretail operations. In such settings, both risk oftheft and fraud are high and, in addition, employeeturnover is high. The use of polygraph examinationsis also recommended to employers as acheck before making promotion decisions (204).
CONCLUSIONS
What is often referred to as "the polygraph" isactually a set of relatively complex procedures forasking questions and measuring physiological responsesin order to detect deception or establishtruth. Polygraph testing is employed for a varietyof uses, ranging from ascertaining the guilt ofa criminal suspect to assessing the honesty of aprospective employee. Because different polygraphprocedures are required depending on intendeduse, it is necessary to consider validity bypolygraph technique and situation. In subsequentchapters, such a variegated analysis is presentedand the scientific and policy contexts are morefully described.| [Back] | [Index] | [Next] |
