Mann -- Lying Flashcards
Define deceptive behavior.
Behavior that indicates lying
What is the Old theory of Non-functional movement in liars?
People who are lying avoid eye contact, fidget or act nervous, touch their face, or put hands over eyes or mouth.
What does the previous research say?
There is no relationship between eye contact and deception and they usually become unnaturally still
What was the previous method to observe lying behavior? What was the issue?
Experimental lab.
Lying wasn’t natural.
Define cognitive load.
The total amount of mental effort being used in the working memory
AIMS/Hypothesis?
AIM 1: to investigate whether there are systematic differences in behavior between lying and truth telling
AIM 1: to investigate individual differences in behavior during lying and truth telling
AIM 3: to investigate real-life lying
AIM 4: to investigate high stakes lying
AIM 5: to extend the work of Vrij and Mann
Hypothesis: liars will not display nervous behavior because…
- Cognitive load and behavioral control
- Previous research supports that liars become unnaturally still, do not decrease eye contact, and that there is no relationship between eye contact and deception
Participants/sampling?
16 police suspects (9 theft, 2 arson, 1 attempted rape, 4 murder)
13 males, 3 females
4 juveniles (13-15) and 12 adults (below 65)
15 Caucasian, one Asian
10/16 already known to police/had been previously interviewed
Got interviews from U.K. police department (self-selecting)
VERY HIGH ECOLOGICAL VALIDITY!!
Sampling for truths/lies?
Files were scoured looking for forensic evidence or substantial reliable independent witness statements to corroborate instances of truth or lie as implicated by the investigating officer
O R
In some cases the suspect initially denies any involvement in the crime, and then confesses after being presented with substantial forensic/witness evidence
Method?
Natural experiment with observation
Design?
Repeated measures (participants are told both truths and lies)
Experimenters?
Mann et. al set up the study and then analyzed the results but didn’t code the video clips
Coding was done by two naïve observers
Observation coding?
2 observers watched the clips, not knowing the study, and would code if the behavior happened
At the end of the tape it would be determined which behaviors happened the most and whether these were during the lie or the truth
Behaviors coded?
Gaze aversion, blinking, head movements, self-manipulations, illustrators, hand/finger movements, speech disturbance, pauses. KNOW WHAT IS MEANT BY EACH OF THESE
Controls?
Double blind design (participants and observers did not know the AIM, researchers didn’t do coding)
Suspects’ ‘truths’ and ‘lies’ were confirmed
Info such as name and address were not included in the clips due to the ease of answering these questions
Apparatus?
A 1 hour videotape with 65 clips of the 16 suspects
27/65 clips were truths and 38 were lies
Each suspect had between 2 and 8 clips
Each clip lasted 41 seconds-6 mins
Coding scheme/response categories on which the observers could record their observations