Polygraph Week Flashcards

Question

Verbal cues | Vrij, 2008

Answer 1

Negative statements Self-references (me, I) Immediacy (direct/clear not indirect/vague) Response length Plausible answers Consistency in answers Contradictions in answers

Answer 2

Pople think less self-references, less immediacy, fewer plausible answers, less consistency and more contradictions suggest deception. Actual indicators are more negative statements, less immediacy, shorter responses and less plausible answers.

Answer 3

Not much of what people believe about non-verbal deceptive behaviours matches research. Difficult to spot in real-time Slow/complex coding (reliability issues) Relate more to cognitive effort than arousal Need to be considered intra-personally

Answer 4

Verbal cues offer slightly better diagnostic ability but: Not reliable Subject to individual differences Need also to be considered Intra-personally Not easily coded in real time Coders can be subjective

Answer 5

``` Rate of breathing Changes in blood pressure Electro dermal activity (palmar sweating) Skin conductance Heart rate ``` Very accurate and sensitive to changes. No set standard to which variables to measure.

Answer 6

NO. It tells that there is a physiological reaction taking place but cannot tell what a person is thinking.

Answer 7

Polygraph uses it. Assumes liars will be more concerned than truth tellers so will show greater physiological changes

Answer 8

Polygraph plays major role in police investigations. Helps prosecutors decide whether to accuse and charge someone. A number of books claim that polygraphs "helped" clear the innocent and ‘solved’ crimes.

Answer 9

Procedures are not standardised to the extent in which they are satisfactory in psychometric terms. No easy way to check the practices used by individual polygraphers. Some aspects (e.g. misleading the examinee) might be contrary to current British Law.

Answer 10

Relevant/Irrelevant Test (Larson) Comparison/Control Question Test (Raskin) Directed Lie Test (Raskin) Guilty Knowledge/Concealed Information Test (Lykken)

Answer 11

Irrelevant: Do you live in the UK? Relevant: On March 12, did you shoot John Smith? Assumed that liars will show a larger physiological response to the relevant question. It was the first most widely used method of testing.

Answer 12

Phase 1: Questions discussed with the examinee. Phase 2: Demo the effectiveness of test Phase 3: Proper test: 3 relevant and 3 control questions run 3 times. Phase 4: Interpretation of results (global or numerical approach)

Answer 13

Compare responses to relevant questions to control questions. Control questions designed to control for effect of threatening questions.

Answer 14

Innocent people react to stronger comparison questions, and guilty examinees will react stronger to relevant questions. Innocents fear control questions more because they arouse concern about subject's past truthfulness whereas relevant questions aren't applicable to them.

Answer 15

Global: Looking at charts and inspecting whether a stronger response is seen for relevant questions. Numerical: Rating responses to each physiological measure on a numerical scoring system. Both subjective as numerical isn't standardised and global is open to interpretation.

Answer 16

Testing is not standardised as examiner has to formulate new control questions for each test (CQT). Examiner misleads examinee to create arousal on control questions (CQT). Scoring is not standardised so is subjective (Both). No evidence supporting assumption that innocents should show a stronger response to control questions (National Research Council, 2003).

Answer 17

Examined over 200 Polygraph field tests. Used scoring sheets of primary examiner who observed test and independent examiners who used only polygraph output. Original examiners: 90% accuracy. Independent examiners: 55% accuracy. Conclusion - Original examiners not solely using polygraph output to judge.

Answer 18

Polygraphs often conducted when no other evidence is available Means innocent suspects cannot prove their innocence via other means. They realise this will become more difficult if they fail test but refusing test may lead to suspicion.

Answer 19

False positive - false accusation of an innocent False negative - saying guilty suspect is innocent False positives more serious in investigations (opposite for catching and terrorists).

Answer 20

Lab and field

Answer 21

Participants lie or tell the truth about a staged event Certainty about who lies and who tells the truth (ground truth). Not realistic – Lies are about trivial issues and ‘liar’ has been told to lie by experimenter.

Answer 22

Polygraph tests in real cases examined Realistic (Ecologically valid). Uncertainty about who lies and who tells the truth as polygraph tests are only carried out when there is no evidence. (Ground truth unknown).

Answer 23

Information provided by direct observation (empirical) as opposed to information provided by inference. Checking the results of machine for accuracy against the real world.

Answer 24

Policemen - paper pencil test Scored own tests (7 cheated). Paper chemically treated so that changed answers could be detected All told suspected of cheating and offered polygraph. All agreed but one ‘guilty’ didn’t show.

Answer 25

3 guilty confessed before taking the test. Final sample 2 Guilty, 13 Innocent Both guilty detected, but 2 innocent rated guilty. 11 out of 13 correct sounds impressive but observer without polygraph also scored 11 out of 13 Independent rater using only polygraph = 7 out of 13

Answer 26

Difficult for examiners to receive feedback that contradicts their verdicts. Guilty verdicts lead to interrogations which lead to confessions or denials. Confessions (including false) are considered as support. Denials (likely from innocents) are considered as “no evidence”. Neither prove the examiner wrong. Confessions by the ‘real perpetrator’ (only way to prove examiner wrong) are unlikely to occur

Answer 27

``` Biting cheek Pressing foot down Contracting muscles Thinking scary thoughts Counting backwards ```

Answer 28

Floyd falsely convicted of murder based upon polygraph evidence. Studied polygraph in prison. Trained 27 prisoners, who admitted to him they were guilty, in countermeasures. 23 out of 27 passed the polygraph test

Answer 29

Based on orienting theory Presents suspects with sets of similar items, one of which will be true. Knowledge is supposedly only one a guilty suspect could have e.g. which murder weapon. Theoretically more sound and less disputed than the CQT. 75% of psychologists considered the GKT to be based on science whereas only 33% said so for CQT.

Answer 30

CQT: 85% accurate for guilty, 70% accurate for not guilty. GKT: 60% accurate for guilty, 95% accurate for not guilty.

Answer 31

CQT vulnerable to false positives because innocents are aroused when answering relevant questions. GKT vulnerable to false negatives because guilty suspects do not know what the correct response item was. Both vulnerable to countermeasures so field study results may not reflect genuine accuracy.

Answer 32

Limited applicability: Can’t use it whenthere are no case facts known and a suspect admits having guilty knowledge but denies guilt. Don't know that a guilty suspect knows the correct answer? Can't ensure that an innocents does not know the correct answer Innocents sometimes know correct answer because it was accidentally revealed in their police interview or in the media.

Answer 33

Guilty suspects will have increased physiological arousal to the correct answer e.g. "she was shot". Innocent suspects should have the same arousal for all answers.

Answer 34

Throughout history it has been assumed that lying is accompanied by a change in the body’s physiological activity. The polygraph accurately measures various physiological changes. Therefore it is claimed that the polygraph can detect deception.

Answer 35

Validity and reliability

Answer 36

Control questions deal with acts that indirectly relate to the crime but do not refer to the crime in question. The suspect has to lie as they are told that admitting the control questionwould conclude they are the type of person that would do the crime. The questions are formed based on what the examiner believes the examinee has done earlier in life.

Answer 37

DLT addresses the standardisation issue of CQT control questions. The control questions are standardised in all situations “Did you ever tell a lie?” People are instructed to lie on control questions rather than coerced into it by the examiner telling them that admitting it would conclude they were probably guilty. The examinees are specifically told to respond negatively and untruthfully to control questions.

Answer 38

Doesn’t consider that the reactions to familiar stimuli is continuous rather than dichotomous. Innocent examinees might have an unregistered gun similar to the murder weapon. The innocent examinee will still react to the gun and therefore be concluded as guilty.

Answer 39

Validity – the extent to which the procedure measures what it claims to measure. Lab studies use mock crimes. Favourable results but guilty participants have little incentive to beat the test and innocent ones won’t be concerned about relevant questions so results are likely inaccurate.

Answer 40

Quality of field studies is low. Hard to discover ground truth (whether a suspect is actually innocent or guilty). Confessions accepted as ground truth but this is problematic. A guilty suspect who is found innocent by the polygraph won’t confess. A lack of confession means the study won’t be included in a field trial and therefore the incorrect polygraph decision won’t be noted (publication bias).

Answer 41

Suppressing physiological reactions to relevant questions/items (mental countermeasures e.g. meditation) Reducing overall anxiety (use of drugs prior to exam) Increasing physiological reactions to control/neutral questions (inflicting pain e.g. muscle tension)

Answer 42

Number of people that can be expected to be guilty in criminal investigations. If 1/1000 employees in an organisation were spies then catching the spy with a polygraph is near impossible. Polygraphs falsely accuse some innocent employees (say 30%). Means 300 people will fail the polygraph test and so impossible to identify spy.

Answer 43

Increasing medication compliance Treating sex offenders Exploring mental states e.g. delusions.

Answer 44

Studied 50 offenders and asked them to take two polygraph tests six months apart. Polygraph increases the disclosure of information such as type of offenses, deviant fantasies/behaviours, number of victims etc. High drop out rate (18% left in final sample).

Answer 45

Not scientifically established as a treatment so unsure of effectiveness. High refusal/drop out rates. Could be perceived as coercive rather than voluntary e.g. sex offenders may be worried that it would make them look bad if they didn’t partake.

Answer 46

P300 response may be useful in line with the GKT test. Has similar accuracy when used alone but when used together it is possible that they may increase accuracy.

Answer 47

Expensive and time consuming. Brain activity more active in deception are also more active in non-deception tasks and therefore false positives are common. More research needed.

Answer 48

Theories CQT is based on suggest innocent suspects will under certain conditions show physiological responses similar to guilty suspects. Blood pressure, skin response and respiration are put into one category but respond differently to psychological states. Current knowledge on physiological response to social interactions have been ignored in polygraph theory. The ambiguity in polygraph measures that research into improving it will only bring minor improvements in accuracy. Research has not progressed over time and policy makers fail to demand better work.