Lie Detection Flashcards
How successful is the lie detection rate of experts?
Who are the most successful experts?
54%
Secret service agents, professional gamblers
Why are experts not great at lie detection?
They rely too much on liar stereotypes (no eye contact, fidgeting, body language, voice)
What would be better methods for lie detection experts?
Content analysis - focuses on word choices, inconsistencies, factual errors
Increase cognitive load - reverse order of events, review details, make it more mentally taxing to keep story straight
What are the common themes among lie detectors?
Lying causes fear and therefore:
Fear activates the sympathetic nervous system
E.g., the dry mouth test
E.g., the bread and cheese test
What was the 1st “Lie Detector”?
It was a measure of blood pressure
By William Marston (1915)
John Larson
He was the first “police psychologist”
Blood pressure + heart rate + respiration = polygraph
His polygraph was used in high profile murder cases at the time
Polygraph means…
“many writings”
Explain the “Keeler Polygraph” by Leonarde Keeler
Blood pressure + heart rate + respiration + electrical resistance (sweat) = polygraph
Portable
Patented
Promoted Professionalized
Polygraph interpretation nowdays
Computer assignment
Automated process
Look to see if the indicators are low or high
Polygraph: Relevant-Irrelevant Technique (RIT)
Relative arousal for:
o _________ (unemotional questions)
o ________(crime relate) questions
Irrelevant
Relevant
Polygraph: Reid Control Question Test (CQT)
o True “control” questions must be _______, but not related to ______ ______.
o Subjects asked for ______ _____ (an instructed lie) and _____ _______ _______.
o It is now _______ _______.
o True “control” questions must be emotional, but not related to current issue
o Subjects asked for directed lies (an instructed lie) and guilt complex questions
o It is now standard method
Explain the Guilty Knowledge Test (GKT) (4)
Who is it by?
Based on the recognition of details
Multiple choice format
Required generally unknown details
By David Lykken
Polygraph and accuracy issues
o _________ ______ ____ ___ ______ (no “Pinocchio response”)
o _________are not ___________
o ______ ______ affects results (psychopathy, anxiety, etc.)
o ___________ __________ influence results (medications, stress)
o _____________ (mental + physical)
Autonomic changes are not specific (no “Pinocchio response”)
Procedures are not standardized
Mental status affects results (psychopathy, anxiety)
Examination conditions influence results (medications, stress)
Countermeasures (mental + physical)
What errors in detecting deception? (3)
Missing a guilty person
Accusing the innocent (false positives)
Errors = more likely to be false positives
Polygraph says for TRUTHFUL - __% actually lying, __% actually truthful
25%
75%
