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Flashcards in Task 5 - Polygraph testing Deck (13)
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Controlled Question Test

- "history"
- assumptions
- administration

- before CQT: control questions were psychologically insignificant to questions of interest
(Are you from Leipzig?)
- CQT replacing the irrelevant query with a comparison/control (accusatory) question
> control questions are likely to elicit lies = "probable lie test"
> probes the integrity of a suspect by asking about past misbehaviours
- is the most commonly used in US

- truthful people will fear/respond more strongly to control question because it is likely that they misbehaved in the past but the did not "misbehave" now (specific crime)
- liar will fear/respond more strongly to relevant questions
--> greater physiological response to what is feared more
--> stress/fear response can be measured

1. Pre-test:
o interview and formulation of questions
--> goal: convince subject that control questions are as important as relevant questions
2. Asking questions while physiological reactions are recorded (skin conductance, heart rate, blood-pressure, fingertips, respiration)
o 3 mins, 10 questions (repeated 3 times)
> Control questions: "Did you ever steal something?"
> Relevant question: "Did you steal the diamond?"
3. If deemed deceptive: confronting to gain admission/confession

--> is not so much one test and more a collection of procedures which have in common that control and irrelevant questions are asked


Controlled Question Test - Criticism

- efficacy
- countermeasures
- accuracy
- theory

- unknown efficacy = conclusive result
> around 90+% --> BUT only claims or field studies --> n valid is lacking!!

- can be cheated pretty simply by countermeasure (e.g.: biting your tongue)

- accuracy claimed by practitioners = near 100% if correctly used
> BUT is over-estimated because no knowledge of ground truth + also, circular argument!
- estimates around 60% = better than chance level but not at all good (especially, if you want to hinder miscarriage of justice)
- efficacy depends on the ability of the practitioner to make the suspect take the control questions as serious

- No theoretical basis
- fear of detection is indistinguishable from the fear of false detection
- biased against innocent suspects (problem if you want to prevent miscarriage of justice)
> if don’t lie in pre-test, machine can’t detect if lying = you are guilty
--> if key ingredient is examiner (make up the questions) = problem because of bias

=> not (very) accurate, not valid, not standardized, nor objective!!!


Controlled Question Test - Why we still use it?

- pros
- other reasons

- more info once you show results to suspects – new disclosure of evidence
- some people with empirically sound approaches find a good validity

- helped occasionally in solving important cases = remembered and used as anecdotal evidence
- risk to the innocent is perceived as minimal = presumption of guilt
- it is confession inducing
- practitioners are blind to criticism (claim they do it correctly)


Offe, H., & Offe, S. (2007). The comparison question test: Does it work and if so how?


- examine the suitability of the CQT for determining guilt

- 60 student pps in a mock crime study (innocent vs. guilty
- pps motivated through monetary reward to be perceived as innocent
- half of pps were informed about CQT and its importance in determining behaviour and the other half was not
- effects of comparison questions were again discussed with half of the participants
- then polygraph examination (CQT) was performed one week and five months after the crime
- interpreted by a law enforcement practitioner

- overall high identification rates (90%) for guilty and innocent people
- consistently quite high identification for innocent suspect (important): lowest ca. 80% in no explanation/no discussion condition
- different identification rates for guilty suspects (less important): lowest 35% in no explanation/no
discussion condition
=> highly successful in identification (win for CQT)

- relatively small sample size



Guilty Knowledge Test

- What is it?
- Japan

= series of multiple-choice questions, each having one critical alternative (true feature of crime) and several noncritical alternatives – need to deny each alternative
- if psychophysiological responses to several critical alternatives are consistently larger than to neutral
--> knowledge is inferred =detects guilty knowledge

- around since 50s in Japan
- used on ca. 5000 criminal cases
- arousal usually measured by respiration (around the chest and abdomen), electrodermal activity (skin resistance response; SRR) and plethysmograph
- has restrictions: not to use with people with heart conditions, mental and/or intellectual handicap, substance abuse disorder, sleep problems
- should be carefully monitored with knowledge is out in the media
- relies on guilty knowledge/memory so things that are more central work better


Guilty Knowledge Test

- procedure

1. Explanation of what is going to happen
2. Attach sensors
3. Card test - to practice the procedure of denying
4. Presenting GKT questions --> no psychophysiological recording made yet
- orienting responses (OR) is reactions evoked by any novel stimulus -> repeated presentations of stimuli, involuntary ORs undergo habituation/response declines
- suspects (if guilty) identifies critical alternatives and recognise critical alternatives beforehand, thus enhance voluntary orientating response by stimulus significance during the polygraph test
- if stimulus meaningful greater orientating response
5. Actual GKT
6. "Double Check" if no item had a special meaning
7. Suspect leaves, no post-hoc interrogation to not give away critical knowledge


Guilty Knowledge Test

- pros

- cons

+ not as many false positives as CQT (study found 6% GKT vs. 16% CQT)
=> protects innocent suspects (rather 10 guilty free than 1 innocent imprisoned!!!)

- less applied in field, so less data
- memory problems = GKT problems
- salient details of the crime are available in the media (try to counteract that with pre-GKT but still!!)
- less efficient (more timely and more work)


Why is the "Guilty Knowledge Test" better than the "Controlled Question Test"?
(Ben Shakhar et al., 2002)

- Daubert criteria better: testability, known error rate, peer review and publication, and general acceptance
--> GKT fulfils it better
- GKT has discriminant validity (CQT is lacking)
- GKT has more theoretical basis
> orientating response
> measures the present of certain knowledge, not
guilt per se
- GKT can and is done blinded --> better to avoid bias and contamination (CQT is not really possible to do blinded because of the nature of the questions)
- can be less abused and is not biased against innocent --> no knowledge = no response (GKT)
--> nervous = response --> assumed guilt (CQT)
- countermeasures are more difficult with GKT
> electrodermal activity (CQT) require 20 s (need to return to baseline) -> enough time for countermeasures
> EEG P300 signal (GKT) only requires 2 s -> not
enough time for countermeasures


Spence, S. A., Kaylor-Hughes, C. J., Brook, M. L., Lankappa, S. T., & Wilkinson, I. D. (2008). ‘Munchausen's syndrome by proxy’or a ‘miscarriage of justice’? An initial application of functional neuroimaging to the question of guilt versus innocence.

Case study

- explore possibility of functional neuroimaging as lie detection

- woman poisoned her child – she denied it
- served prison sentence but continues professing her innocence
- ‘Munchausen's syndrome by proxy’ or ‘miscarriage of justice’?

- scanned her while she affirmed her version and the accusation with modified fMRI protocol
- subject was scanned 4 times at 3 Tesla

- significantly longer response times and relatively greater activation of ventrolateral prefrontal and anterior cingulate cortices when she endorsed her accusers' version
=> neural correlates of making false statements/lying (relating to orienting response)
=> NOT proving her innocence but demonstrating that her behavioural and functional anatomical parameters behave as if she were

Not very conclusive because of many limitations:
- very indirect measure of lying
- if your convinced your right --> cannot be detected
- if so often heard may became automatisms --> cannot be detected
- many countermeasures:
> could move, thus introduce noise
> could deliberately slow response during the putative "lie"
> use alternative cognitive strategy


Should polygraph testing be used with sex offenders?
- Experiment

Grubin et al., 2004


- examined whether polygraph testing would result in sex offenders engaging in fewer high-risk behaviours
(treatment benefit)

- 50 adult male sex offenders taking part in community treatment programs
- assigned to 2 groups:
> "Polygraph Aware" - told they would receive a polygraph examination in 3 months regarding their high-risk behaviours
> "Polygraph Unaware" - told their behaviour would be reviewed in 3 months
- baseline interviews (established relevant behaviour)
- both groups were polygraphed at 3 months
- again at 6 months
- at 3 moments offenders could disclose information:
directly before polygraph, in pre-test, after polygraph

- 1st polygraph: 97% disclosing an average of 2.45 high-risk behaviours (previously unknown to supervisor or probation officer)
- 2nd polygraph: 71 % disclosing an average of 1.57 behaviours
--> no significance btw. the groups
- mostly disclosed during the pre-test or when having failed the polygraph
- majority failed the first do everybody did a second
=> concluded that polygraph testing resulted in offenders engaging in less high-risk behaviour
- more reporting to supervisors afterwards (but not recoded only mentioned by supervisor)

- no control group with no polygraph (so saying high risk behaviour was lowered is a bit of stretch)
- also the reported behaviours got lower (maybe the suspects got better in counter measures)
- small sample
- selection bias: there was a high drop out rate so it could be that the motivation was the factor which lowered the high-risk behaviour and not the polygraph testing

That is really my least favourite experiment of all time!!!


Should polygraph testing be used with sex offenders?
- The statement: NO

Ben-Shakhar, 2008

-> see critique of the CQT

- in case of sex offenders it is even less applicable because the nature of the questions
> normally: relevant question about known crime
> sex offenders: relevant questions about possible or hypothetical, future crime (event free)
--> more vague, less valid
- cognitive distortions of sex offenders may lead to inconclusive results because they are not nervous about these acts
- repeated examination of sex offenders may result in habituation

- discourse are hard to verify (no ground truth)
- can elicit false confession (to explain wrong failing)


Should polygraph testing be used with sex offenders?
- The response: YES

Grubin, 2008

- pro post-conviction sex offender testing (PCSOT)
- criminal record often underestimated
- could help for treatment
- could help to decide for/against parole etc.
--> can facilitate disclosure
- not unethical = voluntary
- bogus pipeline effect is a good thing

- 4 types of tests employed
> sexual history disclosure
> maintenance (to see whether the person stays cooperative)
> denial, or index offence disclosure (to get a better idea of circumstances which led to offenses)
> specific issue / monitoring exams (monitors single issue)

- different to suspect interrogation
> not an interrogation but a interview
> regularly applied --> rewards progress
> not so impactful (no one is going to jail for failing it)
> accuracy rates in the region of 80% are sufficient to inform treatment and management
> CRUCIAL: false positives are not detrimental (different criteria)
> false confession rates are lower (less than 10%) and do not have such a bad impact (already in jail or under supervision)

- Verifying info
- Compliance with parole
- Low rate of reoffending --> caution – can fake
- Large increases in self-disclosing info
- Reductions in high risk behaviour
- Increased reporting of relevant behaviours to supervising probation officers
- Report it to be helpful


Should polygraph testing be used with sex offenders?
- Critical Review

Meijer et al., 2008

- research shortcomings
- Bogus Pipeline

=> main take away: the research with supports the beneficial effect of using polygraph test on sex offenders is either unsound or lacking altogether

methodological pitfalls:
- no controls
- sampling bias (only highly motivated)
- no ground truth

- no/little research if it reduces recidivism (which should be the main goal)

Bogus Pipeline Effect:
= expectation of an upcoming polygraph examination is enough to make offenders disclose information
- offenders are required to be completely honest for successful completion of their treatment program, BUT CQT relies on deception toward the examinee