test3- deception Flashcards
(54 cards)
Cesare Lombroso (1885)
- first person to look at blood pressure with cuff to see if someone lying
- founder of movement that criminality could be bred out of species of humans
William Marston- pneumography
- Frye Criteria; advocated to have him testify with his lie detection device, ruled against (device not generally accepted in field)
- was a polygrapher; called himself father of numograph (however wasn’t actually inventor)
what does a numograph measure?
-primarily blood pressure
what does a Polygraph measure?
- measured many things (ANS response)
- skin conductance, heart rate, breathing rate
what were polygraphs primarily used for until the late 80s in the US?
- employee testing (on hiring or some point during employment to identify theft or drug use on the job)
- now illegal
- no longer allowed in court (still used in investigation)
common uses of polygraphs
- criminal investigation
- interrogation
- insurance
- employee testing (limited to specific investigations of job-related wrongdoing)
- screening (assess candidates reliability and loyalty)
- polygraph disclosure tests (uncover info about offenders past behavior)
what is the main element that varies when giving a polygraph ?
how the questions are provided/ how user is questioned
Name the three main polygraph techniques
- relevant/ irrelevant test
- comparison questions test (CQT)
- concealed information’s test (CIT)
Relevant/ irrelevant polygraph test
- most primitive, not used much
- ask irrelevant questions and compare response to relevant questions (know ground truth of irrelevant questions so can tell when lying)
- often used on Dr. Phil
Comparison Questions Test (polygraph)
- most common technique worldwide
- relevant, irrelevant, and control/comparison questions asked (repeated multiple times)
- comparison questions should be emotionally arousing and know ground truth of, usually don’t have reason to lie about, tailored to person, not about issue at hand
- includes pre-test interview where develop comparison questions, learn about background, and convince suspect of accuracy of test
- guilty assumed to respond more to relevant Qs, innocent more to irrelevant Qs
- don’t have to respond to questions but better if do
Concealed Information Test (polygraph)
- determine if suspect knows info about crime that only person who committed would know
- ask multiple choice questions, give them time to pick answer (better to answer as know they are listening)
- measure ANS response (skin conductance) to correct answer
- only works if remember details of crime and if salient details only known by perpetrator
- most popular in Japan and Israel
- not used a lot b/c need many questions for accuracy, hard to come up with them as must be very familiar with case, and not a lot of motivation by polygraphers to switch to diff technique
how are lab studies conducted to test polygraph accuracy?
- have people lie and tell truth and see if can tell
- advantage: experimenter knows ground truth
- disadvantage: limited application to real world (motivational differences)
how are field studies conducted to test polygraph accuracy?
- involve real-life situations, actual suspects and actual polygraph examinations
- compare original examiners to blind evaluators
- see where used, if person fund to be guilty and said guilty= success (PROBLEM: conviction doesn’t necessarily mean guilt)
- could look at cases where DNA evidence said they are guilty
- many use confessions to establish ground truth
what are two ways to establish ground truth?
- judicial
- confessions
* both have their own issues*
what did CQT lab and field studies discover?
- results do not suggest that polygraphs are very accurate (bust still better than guessing)
- bias towards false positives (say your lying when telling the truth)
what are some CQT countermeasures?
- physical: tongue biting, pressing toes to floor
- mental: counting backwards from 7
- Honts, Raskin, Kirchner (1994): showed success with both measures; something mentally taxing while answering can show success
- can also learn to escape deception if learn rationale underlying CQT
what did CIT lab and field studies discover?
- false positives low, but false negatives high
- goof at identifying innocent, not as much for guilty
- Ben, Shakhar & Elaad (2003): accuracy improved with motivation, 5 or more q’s and verbal response
- in field study, if add more autonomic measures, false neg rate went down a lot and false pos increased slightly
CIT countermeasures?
- ant-anxiety drugs (ex. diazepam) –> have found to be ineffective
- other measures not well studied
which polygraph type should police be more inclined to use and why?
CIT b/c lower false positive rate- ppl are innocent until proven guilty, and wouldn’t accuse as many people falsely
Patricj & lacuna (1989) ‘group contingency threat’ study
- in real life there are consequences for polygraphs
- got ppl to participate from corrections facility, told them there was a bonus for participating
- told to convince a person you are telling truth, if everyone succeeds, all get bonus, if you fail, no one gets and they get told it was you who failed (increases stakes)
- Results: no difference between psychopaths and those with APD, no difference between psychopaths and non
NRC 2003- review of polygraph evidence
- tried to come up with recommendation regarding the polygraph
- physiological responses measured by polygraph are not uniquely related to deception (happen for many reasons)
- theoretical rationale for CQT is weak (compare and relevant questions are weak)
- lab studies overestimate accuracy
- no field studies satisfy min criteria for quality study
- claims about polygraph today are same as those throughout history (claim high accuracy but rarely reflected in research)
polygraph admissibility in Canada
- not admissible in Canadian criminal court of law
- results first submitted as evidence in US court in Frye v. US, but denied to be admitted
R. v. Beland (1987)- polygraph admissibility case
- only evidence was testimony of accomplices (hinged on witness credibility)
- tried to introduce polygraph evidence; just re-established rules against oath helping (bolstering credibility) which you cant do
- issue= distraction, as may get into question of if polygraphers are valid experts instead of actual issue
- if polygraphers had no machine wouldn’t be allowed to testify
- if whole case hinges on credibility, maybe should be allowed?
‘mystique of science’ or ‘aura of infallibility’
- worry that juries are inordinately influenced by scientific backing of the polygraph
- bias may make polygraph less accurate
- research done to see if jurors really influenced, found to be spotty with little affect on jurors
- other things jurors make decision on, but if case hinges on believability, may have an effect