Lie Detection Flashcards
What are the main techniques used for lie detecting?
Polygraph
EEG
fMRI
What is Ekmans approach to lie detection?
That lies are hard to detect as they are meant to mislead, and may be given away by “micro-expressions”.
Edman suggests that _______ in ability to detect lies does not increase ______ _______, and that experts can only detect lies at _______ ________.
confidence; actual ability; chance level.
“Liars avoid eye contact” - evidence or belief?
Belief (no evidence).
“Lies are inconsistent over time” - evidence or belief?
Belief (evidence shows the opposite!).
“Liars show increased body movement” - evidence or belief?
Belief (no evidence).
“It’s easier to detect lies face to face” - evidence or belief?
Belief (observers better than interrogators).
Who was the first polygraph examiner?
Keeler.
What are “leakages”?
Pauses and errors in speech (lack of story prep).
Raised pitch/louder speech (suggests anger/fear).
Frequent swallowing, fast shallow breathing, sweating, blinking, pupil dilation (signs of emotion).
What types of questions are used with the polygraph?
Guilty knowledge
Relevant/irrelevant
Directed lie
Emotive control questions
What are the 3 main weaknesses of using the polygraph?
It is hard to tell whether someone is lying or just emotional.
Can learn to fake responses.
It is controversial but still widely used.
What is the most useful ERP response for lie detection?
P300
What are the weaknesses of EEG for lie detection?
P300 not easily detectable in schizophrenia and depression.
Only sows recognition rather than guilt.
Langleben (2005) suggested that participants who lied during fMRI scans showed increased activity in…
prefrontal and parietal regions.
What are guilty knowledge questions?
Questions which indicate awareness of information known only to police and the offender.
What are relevant/irrelevant questions?
Truth is indicated by similar responses to both types of questions.
What are directed lie questions?
Asking people to respond falsely to simple questions. Innocent people are more concerned about lying to control questions.
What are emotive control questions?
Innocent people show more emotion to control questions, and guilty dhow more emotion to relevant ones.
What is the main weakness of all lie detecting methods?
They rely on the expression of emotion, and therefore don’t indicate whether the emotion is due to guilt or not.
