Polygraphtests were invented by William M.
Marston in 1971. Theyhave been conducted for many years and widely used by enforcement agencies wheninterrogating an offender. The lie detector machine measures their bloodpressure, heart rate and respiration while the law asks questions related totheir offence. One method of polygraph is Comparison Question Technique, or CQT,which compares responses to relevant questions with responses to controlquestions (Elaad, 2003). Control questions are used to deal with relations tothe crime but not the crime itself. This is to test the criminal, evoking themto lie.
Relevant questions address the crime and can be very specific. It’sbeen said that guilty people should show more psychological responses torelevant questions rather than control questions. The Comparison QuestionTechnique is very popular amongst law enforcement, forensics and nationalsecurity screening due to its accuracy, although its caused controversy.
Theseunderlying problems are mainly theoretical. There’s no evidence that certainpsychological responses are related to deception; innocent people could just benaturally nervous when asked questions. This can show that polygraph tests arenot always accurate or reliable. The lack of standardisation means that muchdepends on the skills of the individual polygraph examiner who formulates thequestions. This essay will look at the advantages and disadvantages of polygraphtesting and the CQT when catching criminals who have committed sexual offences. Gannon, Wood, Pina, Vasquez and Fraser (2012)carried out a pilot study to see whether mandatory polygraph testing should berolled out across England and Wales.
They wanted to find out if testing wouldmake offenders more honest when asked certain questions, while supervised bytheir managers. They found there was increase in clinically significantdisclosures which can change how they’re treated in prison. This study has beencriticised as the results were based more on the belief that the test wouldshow that the offender was lying rather than when. This throws doubt on thereliability of polygraph testing. Acritical review by Meijer, Verschuere, Merckelbach, & Crombez (2008) shows that recidivism is a serious problemamong sex offenders and must be reduced. This has shown a major increase inusing polygraph tests to assess convicted sex offenders. This is due to itbeing compared to the urine test analysis that is used on drug addicts (English, Jones, Patrick, & Pasini-Hill, 2003). Both of these methods have shown to be accuratewhen validating an offender’s truthfulness.
Over the years, probation officers have beentrained to carry out polygraph testing on sex offenders. This is to make surethat sex offenders are caught in time before more serious offences are caused,such as rape. Sex offenders are less likely to confess their crime compared topaedophiles and they may even argue their case in court to try and get alenient sentence. Unfortunately, this can lead them to re-offend. Polygraphtesting can be known to produce prediction errors, such as false positives andfalse negatives. False positives are when innocent people are deemed guilty andthey have a higher rate of community supervision. False negatives are theopposite with guilty people regarded as innocent and getting lower supervision,making it easier for them to re-offend.
Tounderstand a sex offender’s behaviour, past or current, they are asked to completea sexual history disclosure test. This requires offenders to complete a form listingtheir offences and victims. This list is then discussed by their supervisorsand therapists. Levenson (2009) argued that social workers are unable to assessrisk without essential past history. Without this information, it is not knownwhether the offenders are just a risk to adults, or children as well. Cook(2011) carried out a between-subjects test by taking a sample of 166 sexualoffenders, who were convicted between January 1999 and August 2005. Theseparticipants were male and had been convicted and supervised locally.
They weresplit into two groups: 93 received the sexual history test and 73 did not. Findingsshowed that those who had undergone the sexualhistory polygraph examination were less likely to re-offend. Children are known to be victims of sexual abuse. Thisis said to be linked to offenders’ cognitive distortions. They may minimizeharm caused by the abuse, perceive children as desiring sexual contact withadults, or perceive their sexual contact as socially acceptable (Gannon & Polaschek, 2006; Ward, Hudson,Johnston, & Marshall, 1997). A way to reduce cognitive distortions isto ask straightforward questions. Examiners are unable to determine whether theoffence took place, so they have to formulate their questions more vaguely.Offenders may be questioned about sexual contact but it could be normalinteraction; the examiner doesn’t know.
Due to cognitive distortions, theoffender may not respond, leading to a false negative outcome. Thereare many factors that can affect the accuracy of CQT. One is repeated testingof the same offender. Andreassi (2000) states that physiologicalresponses decrease when constantly triggered and can cause an incentive in theoffender. Repeated testing may force offenders to start using countermeasuresto alter test outcomes. This can be both physical or psychological techniques,such as “fooling” the machine or unable to use the results in court.
Unfortunatelyfor examiners this is easily undetectable and can be troublesome. Re-testingthe same offender multiple times can not only Thepost-conviction sex offender polygraph test has been said to have an effect onreducing recidivism. However, there is no proof that this is true. Grubin,Madsen, Parsons, Sosnowski, & Warberg (2004) thought that the polygraphtest would influence offenders’ behaviour therefore expecting to see areduction in high risk behaviour. Their study showed that using PCSOT canreveal new information this doesn’t stop offenders from participating in highrisk behaviour.
There hasbeen some debate among critics about how ecologically valid CQT is. It’s been argued that there’s no way to knowhow strong responses may show signs of a criminal’s guilt and it could be thatthe suspect is innocent. This is due to fear of being detected. Laboratorystudies have been known to lack ecological validity due to a non-real-lifesetting. Participant’s wellbeing is not affected by failing the ComparisonQuestion Technique.