DoLie Detector Tests Accurately Determine Truthful Statements?
DoLie Detector Tests Accurately Determine Truthful Statements?
Shniderman(2011) provided the historical context of lie detectors invention byexplaining that lie detection tendencies began as far as 300 BC.During ancient periods, people used to listen to heartbeats ofexaminees during interrogation processes. Others used to monitor theeye movement and other non-verbal cues in the attempt of determiningthe truthfulness of the statements provided. However, as the worldmoved towards industrialization, neoliberal ideas facilitated theinvention of machines that people believe could be used to detectlies in the process of ascertaining the truthfulness of theinformation provided by people. These devices have found extensiveusage in the criminal investigation department where law enforcementagencies use them to determine whether the information they receivefrom suspects are truthful. In Britain and United States, the deviceshave been used to facility therapy treatments for sexual offenders.Specifically, the origin of polygraph tests can be traced to 1730when a scientist, Daniel Defoe, made a recommendation for the lawenforcement department to embrace scientific approaches in solvingmost cases (Shniderman, 2011). He called out for investigators tomonitor the heart rate and other physiological characteristics ofpeople during interrogation to determine the truthfulness of theinformation they provided. This recommendation and others formed thebasis upon which lie detectors emerged.
Alie detector or a polygraph as sometimes referred is a device thatcriminal investigators use in most cases to determine whether aperson is telling the truth or lies. The design of the instrumentallows it to monitor the vital physiological aspects of a person’sbody, including blood pressure, pulse, respiration, and palm sweat todetermine whether a person is truthful (Houser & Dworkin, 2009).The device combines the various instruments that would normally beused to check on the physiological conditions of an individual basedon specific stimuli. The working process includes asking specificquestions that would trigger particular emotional responses. Theseresponses are monitored and displayed on the device. A logicalconclusion is formulated based on the records provided by theinstrument. The signals picked by the device are compared with thenormal physiological status of a person to make logical conclusions(Houser & Dworkin, 2009). Variations in the physiological levelswould imply that fake. The analysis of the information is done byexperts in the field of such analysis. However, the ability of liedetectors to be accurate has been a source of controversy in thescientific, social and political arenas across the world. Therefore,this paper seeks to determine whether lie detector tests accuratelydetermine truthful statements.
Principleof Operation of Lie Detectors
Polygraph’sworking principle is based on the tenet that truth tellers havedifferent physiological responses from liars. Therefore, if thehomeostatic physiological statuses of people can be predetermined,then they can serve as the basis for comparison for otherphysiological responses (Ligons, 2000). The idea of this process isthat any slight variation in the comparison of the two statutes ofphysiological responses can be used to determine whether a person istruthful or a liar. Therefore, the resultant data after polygraphtest is compared against the predetermined homeostatic physiologicaldata to determine whether there was any meaningful variation. Liedetector machines are fitted with various sensors capable ofdetecting variation in physiological aspects of a person’s body.Such physiological aspects include blood pressure, heartbeats, andrespiration among others. The examiner is trained and skilled indetecting these physiological variations. The second assumptionregarding the process is that physiological variations result fromfear of being caught or guilt after providing false information.There are various methods of examining subjects. However, the mostcommonly used method controls Question Technique (CQT) (Ligons,2000). CQT involves asking three types of questions. The firstquestion is neutral in nature. The second question is relevant whilethe last question is meant to serve as the control.
Neutralquestions seek to assess the physiological status of a person whenanswering questions truthfully (Ligons, 2000). Therefore, theexaminer asks questions whose answers are predetermined. Forinstance, the examiner can ask the subject his or her name, age, nameof spouse or location of residence and monitor the physiologicalbehavior displayed by the polygraph. The relevant questions are theinterrogation questions or the questions of interest to the wholeprocess. For instance, such questions would seek to determine whetherthe subject participated in a particular criminal activity (Ligons,2000). Control questions revolve around the areas of relevantquestions. For instance, an examiner may ask the subject whether hehas ever participated in the crime in his life. The examiner may alsoask whether the subject may have taken something that is not his orhers at any particular age. Like neutral questions, control questionscan also be known. Their relevance to the test process is that theyprovide credibility to the responses provided when relevant questionsare asked. Control questions tend to make people lie with the aim ofdetermining their physiological responses when they lie. In thisapproach, the examiner has physiological details of a subject when heor she is being truthful and lying. Therefore, the relevant responsescan be analyzed by neutral and control responses to determine theircredibility.
The truthfulness of the replies provided is thus determined by theextent of variation from the truth level established by neutralquestions. Correspondingly, the lack of truth in the responses isdetermined by variation from the deception level determined by thecontrol questions. The credibility of the outcome depends heavily onthe ability of the examiner to illustrate beyond doubt that the testprocess was objective and accurate. However, the process has severalassumptions that have formed the basis of most criticism. Firstly, itis assumed that physiological responses are triggered by stressresulting from guilt or fear of being caught. The process alsoassumes that people have similar physiological characteristics, andthus can be tested using similar methods. The process also impliesthat people cannot develop countermeasures that can be used to passpolygraph tests despite providing false statements. These factorsform the most important variables that determine the credibility oflie detector tests. Therefore, this paper hypothesizes that liedetector tests do not determine truthful statements accurately.
Thoseon the opposing side maintain that whereas polygraphs can detectphysiological changes in a person’s body, it cannot determine truthfrom a lie accurately (Houser & Dworkin, 2009). The supportingside claims that the device can be used to determine the truth ofstatements because physiological changes in a person’s body aretriggered when he or she is not telling the truth. Furedy andHeslegrave (2008) explained that the validity of lie detectorsregarding their abilities to detect whether a person is telling thetruth when interrogated depends on various factors. Such factorsinclude the level of skills of the interrogator, the physiologicalstatus of an individual during the before the process, the processesused to determine scores, the manner of questioning used, and thephysiological measurement indices targeted. The ability of polygraphsto provide reveal whether someone is telling the truth can be said tovary according to how the mentioned factors are controlled (Furedy &Heslegrave, 2008). An appropriate control of the determinant factorswould lead to a high degree of accuracy in the conclusions gatheredafter the examination. Correspondingly, lack of proper control of thedeterminant factors would compromise the ability of the device toperform its function accurately.
Theevidence supporting the inaccuracy of polygraphs in determiningwhether a person is telling the truth is overwhelming. Furedy andHeslegrave (2008) also discussed that the fact that the device worksby measuring the physiological changes of a person`s body againstpreviously established baseline measurement makes it a useful toolfor determining the guilt level of the person rather than whether heor she is telling the truth. People can both be guilty of telling thetruth or lies about a situation depending on their perception of theinfluence their responses have on the situation. If a person answersquestions truthfully, but feels guilty for speaking it, they arelikely to be stressed and trigger specific physiological responses.The device would most likely pick these signals. However, it wouldnot determine whether the physiological signals were triggered as aresult of guilt for speaking the truth or as a result of speakinglies. Correspondingly, a person may feel less stressed even afterproviding a false response, especially if he or she feels thatproviding the incorrect response was necessary than telling the truthabout a situation. The polygraph, in this case, would reveal thatthis person is truthful because of the lack of variation in his orher physiological status.
Iacono (2000) dismissed the relevance of polygraph tests by the lackof scientific proof in its principles of operations. The authormaintained that there is no distinctive physiological aspect thatserves as an indication of truth or lie. Examiners have tried toredress the lack of scientific basis in their approach to developingquestions upon which they compare the responses of the examinees.These items are known as control questions (CQT). Control questionsdetermine the homeostatic status of an individual`s physiologicalresponse before interrogation. Any slight variation from thishomeostatic status of a person`s physiological response would signifythat he or she is deceiving the examiner. The general assumption ofthe process is that when people give false information, they tend totrigger specific physiological signals such as sweaty palms andincreased heart rates as a response to the amount of stress they areexperiencing. It is this assumption that Iacono (2000) disputes byasserting that there is no distinctive physiological aspect thatserves as an indication of truth or lie. Physiological processes canbe triggered by various factors such as sicknesses, boredom, andstresses among others.
Thecontrol questions do not provide adequate physiological controlbecause one is left to wonder whether the physiological response ofthe person being interrogated was triggered by lies or because he orshe upset for being wrongly accused. The probability of passingpolygraph test rests on how a person answers the related questionsrather than whether he or she answered the questions truthfully. Thefact that there are no specific physiological responses signifyinglying may be exploited by people. Studies have demonstrated that theaccuracy of polygraph tests varies on how well a person is conversantwith the related process. Those who are aware of the similar processcan find ways of manipulating it to give the false impression thatthey are truthful whereas they are providing false information aboutthe interrogation. According to Gershman (2008), the level ofpolygraph test accuracy has always been said to range between 70% and90% depending on how it is used. However, this has not stopped mostcourts from disputing the reliability and accuracy of the relatedinformation.
Inmost courts of law in Britain and America, polygraph tests do notcount as beyond the reasonable doubt evidence. Such courts refuse togive search and arrest warrants based on the evidence collected frompolygraph tests because of the related controversies. The accused caneasily argue that polygraph tests lack scientific basis thus, itsresults cannot amount to anything useful in court proceedings(Gershman, 2008). In technical terms, polygraph tests measure theactivities of the autonomic nervous system. The autonomic nervoussystem is responsible for maintaining the homeostatic status of aperson`s body in a way that allows him or her to adapt to changingenvironments (Langan, 1995). Therefore, the autonomic nervous systemregulates the body`s physiological changes such heart rates and palmsweats normally in ways that people are not aware. The concept of"flight or fight" describes how the autonomic nervoussystem prepares a body in threatening or scary circumstances. Whereasit is true that lie detectors measure the activities of autonomicnervous system, the same cannot be said for honesty or truth (Langan,1995). This fact makes polygraph evidence inadmissible in the courtof law. The fact that physiological responses can be triggered byvarious circumstances at the time polygraph tests are conducted makesit unrealistic to assert that the process can determine whether aperson is lying or telling the truth accurately.
Maschke& Scalabrini (2005) discussed that lie detectors can bemanipulated into providing false signals using various tactics. Thefocal point of every manipulation strategy revolves aroundconditioning the body to produce false physiological responses whenregardless of the controlling questions. The most predominanttechnique used to augment the physiological status of a body whileanswering controlling questions involves diverting the mind bysolving arithmetic mentally, focusing happy moments, and causing painto the body by biting the tongue. Furthermore, there is no convincingrecord of any interrogator having demonstrated that he or she cancounter such measures (Maschke & Scalabrini, 2005). Therefore,the ability of lie detectors to determine truthful statements is notassured until measures are developed to counter the techniques usedto manipulate the body’s physiological status when answeringcontrolling questions.
Frequentexposure of people to certain control questions results inhabituation. Habituation is the case whereby the physiologicalresponses of a person diminish if he or she is repeatedly exposed toa particular stimulus. In this context, it is not easy to determinethis factor before polygraph testing. The test conclusions may befaulty because of habituation. A person who has undergone habituationmay not show adequate physiological changes when asked specificquestions because he or she has become accustomed to such questionsfrom past experiences. Some people can also train before the test. Ina situation where a lot of unknown factors can compromise thevalidity of results, it is not realistic to make an absoluteassertion that lie detectors can be used to determine the truth inthe responses people give (Rosky, 2013). A guilty person may bewrongly set free if a major decision was to be based on the resultsof the polygraph. Correspondingly, an innocent person may be wronglyconvicted for lying whereas the physiological process was triggeredby other feelings such as fear, anger and depression.
Inmost cases, polygraphs are used in a way to scare people intosurrendering information. Grubin (2010) maintained that there is noreal scientific basis supporting the working principle of liedetectors when used in the context of creating fear. He furtherdiscussed that polygraph tests are inaccurate. In most cases,examinees are frightened by the idea of a lie detector, and not thatit detects when a person is not disclosing accurate informationregarding a circumstance. In other words, lie detectors are devicesused by examiners to con people their private information. In thiscontext, the reliability of the instrument is in doubt owing to itsweak principle of operation. Examinees who know that a lie detectoris just an idea to scare people into giving information would bedifficult to deal with or coerce into surrendering information.
Grubinet al. (2004) conducted a study to determine whether polygraph testsor the idea of such tests, would make past sex offenders would reducerisky behaviors. The study engaged fifty adult male sex offenders whowere being treated in community treatment programs. They were dividedinto two groups, including the polygraph test aware and unawaregroups. The idea was to establish whether there would be asignificant difference in the behavior of participants between thetwo groups. The first groups were made aware of the polygraph testingafter a particular period while the second group was unaware ofpolygraph testing. The hypothesis of the study was that polygraphtesting would make sex offenders to engage in fewer risky behaviorscompared to those who are not aware of polygraph tests. The firstpolygraph test between the two groups revealed no significantdifference in the behavior change. However, the subsequent testsshowed a substantial difference between the two groups. The firstgroup engaged in fewer risky sexual behaviors than the second groupowing to the fact that they were afraid of being caught.
However,a usable conclusion could not be drawn from the test because thereliability of the responses provided by the first group could not bedetermined. Participants may have said what they thought theexaminers wanted to hear about their behaviors. The determination ofwhether the information provided by examinees is valid is challengingto determine. An individual’s physiological characteristics canchange due to different reasons such as guilt after providing a rightanswer or just fear that he or she may still be regarded as a liardespite providing accurate information. Scientists are yet to providea conclusive means of differentiating the physiologicalcharacteristics of people. Until then, polygraph tests cannot beregarded as accurate owing to the fact that the device tests for thephysiological changes in a person during the examination. Kokish etal. (2005) shared a similar view by inferring that lie detector testsare probabilistic in nature and do not follow any known scientificprocess. The validity of the information is further compromised bythe inability of examiners to control variables such as habituation,error in physiological signals were given and the ability of theexaminee to manipulate the process. The situation is furthercomplicated by the fact that in most cases, polygraph tests followscreening test routines rather than diagnostic test routines.
Currently,there are few pieces of evidence supporting the validity of polygraphtests because mostly they are used in screening tests. Screeningtests are where the outcome is not known in advance. Investigationtests would allow examiners to compare the results they get frompolygraph tests against the known outcomes (Kokish et al., 2005). Inthis case, it would be easy to estimate the accuracy probability ofsuch test. The probabilistic nature of the results makes lie detectortests an enormous gamble when used to make important decisions, suchas the ones concerning behavior change of sexual offenders. There isno evidence regarding the control of polygraph testing variables suchas habituation. Thus, examiners cannot declare that their tests havea high degree of accuracy. Investigative questions are not ambiguousbecause they revolve around known circumstances. Screening questions,on the other hand, are vague because they try to find the examinee`srole in a circumstance that is not determined.
Consideringthe principle of the usage of lie detectors, investigations would bethe ideal framework for the application. Lie detectors focus ondetermining the changes in physiological aspects of an examinee whenspecific questions are asked. The data collected are analyzed laterto determine variations. The rationale is that deception triggersspecific physiological responses such as sweaty palms and increasedheart rates among others. In this context, it may not be realisticto make conclusions based on a person`s physiological responses whenscreening questions are asked. The application of polygraph tests indetecting validity of the answers is relatively more realistic ininvestigations than in screening tests (Janušauskas, 2014). Liedetector tests can be perceived as a good idea whose time is yet tocome. If all the doubts surrounding the control of variables would besolved, then there would be no question that the tests are accurateand rightly determine whether an individual is telling the truth ordeceiving the examiner.
Polygraphsare extensively used to solve crimes, especially those regarding sexoffenses. Polygraphs are used to determine the truthfulness of theinformation provided by sex offenders with the aim of facilitatingappropriate therapy treatment processes (Meijer et al., 2008). Sexoffending is widely regarded as originating from psychologicalchallenges of a person. For instance, most males force females intohaving sex with them to feel powerful and domineering. Thesetendencies cannot be corrected through incarceration alone, but alsothrough appropriate therapy sessions. Thus, polygraphs have beenwidely used to determine the validity of information provided by bothvictims and perpetrators of sex offenses. However, studies indicatethat recidivism among sex offenders continue to be a challengedespite using lie detectors to determine the validity of informationprovided by sex offenders and victims of such offenses.In theUnited States, Bureau of Justice Statistics reported thatapproximately 5% of the 10,000 sex offenders released in 2003 wererearrested for the same crime (Meijer et al., 2008). The high rate ofrecidivism among sex offenders highlights the fact that most of thelie detector tests are inaccurate and may not be relied on to makethe therapy treatment decisions.
Langan(1995) maintained that dishonesty cannot be measured using anyprocess. Other aspects of human behavior that cannot be measured arelove, hatred, anger, and happiness among others. This fact is thereason there is still a high rate of recidivism of sexual offendingand white collar crimes among others in most countries. People areunique when it comes to their autonomic liability. Some people wouldmaintain astonishing calmness even in the face of danger whileothers would flee the scene of the danger or potential dangerimmediately (Langan, 1995). Correspondingly, some people do not showwhen they are hurt while others cry over the same. It is alsodifficult to determine whether some people get angry because they areever happy. On the other hand, it’s hard to determine whether somepeople are impressed because they are ever sad, even in situationswhen one would expect them to be happy. The concept of autonomicliability further compromises the credibility of lie detector testsabout their ability to accurately determine whether a person is lyingor telling the truth. In one test process, it would appear as if theexaminee is telling the truth, whereas he or she can maintaincalmness in stressful situations. In another testing process, itwould appear as if an examinee is telling lies whereas he or she hasthe tendency of panicking whenever confronted with stressful issues.
Vrijet al. (2010) examined various literature that conductedmeta-analysis studies to determine whether there were verbal andnon-verbal cues associated with lying. The authors dwelt extensivelyon the most extensive and thorough meta-analysis in the scholarshiphistory to enhance the reliability of their findings. The mostextensive and detailed meta-analysis study of all the analyzedstudies identified 158 cues. Apparently, 118 of those cues did notsignify deception in any way. Among them were the cues commonlyassociated with deception, such as shifting gaze, shifting posture,and pauses among others (Vrij et al., 2010). Interestingly, the fewcues that had some significant association with deception were oftenoverlooked and not easy to determine using the conventional liedetection processes. The study also determined that part of thereason it would be difficult to detect lies using polygraph tests isbecause liars and truth tellers portray insignificantly differentbehaviors. The thin line of difference between liars and truthtellers makes most police manuals containing deceit cues inaccurateand unrealistic to use.
Vrij et al. (2010) also maintained that the polygraph tests arefurther compromised by the fact that most people are often afraid touncover truth because of their unpleasant nature. The effect ofunpleasant truth on people is sometimes referred to as the “OstrichEffect” to mean that some people prefer to deal with thefabrication of truth rather than the main truth. The fact that mostexaminers are afraid of uncovering the truth gives examinees theopportunities to use countermeasures to their advantage.Countermeasures include the techniques that would make it appear asif a person is providing truthful information even when he or she isnot truthful (Vrij et al., 2010). Embedding lies in truth is one ofthe common ways of passing polygraph tests. In this case, examineesconsole themselves that they have provided a substantial amount oftruth, just not the entire truth. In this case, the physiologicalsigns remain at homeostatic state due to lack of stress. In normallife scenarios, people tend to overstate facts when they do not likethings. They overstate facts to avoid judgments and convincethemselves that their behaviors are justified.
Thispaper has adequately determined that while a lie detector is animportant idea towards enhancing criminal investigation processes, itstill lacks scientific enhancements to make it credible. As it isnow, it cannot be conclusively declared that lie detectors liedetector tests accurately determine truthful statements because ofvarious loopholes in the process. Firstly, cognitive processes suchas deception, anger and happiness cannot be measured throughpolygraph tests. Secondly, most of the cues commonly observed duringinterrogation processes do not have an association with lying.Thirdly, the polygraph test process can be counteracted by hardcorecriminals using clever approaches such as embedding lies within thetruth. The concept of habituation also compromises the credibility ofthe related process. Correspondingly, the notion of autonomicliability also compromises the credibility of the process. Lastly, anoverwhelming amount of application evidence suggests that polygraphtests have not been effective in facilitating recidivism of sexualoffenses. Therefore, it is the recommendation of this paper that thementioned variables be controlled using scientific means to enhancethe credibility of polygraph tests.
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