Vrijj And Mann: Detecting Lies (Suspects)

Question 1

PPs?

Answer 1

Volunteer same

• EXP1: 1 convicted criminal
• EXP2: 59 male, 6 female police officers West Sussex

Question 2

Method EXP1?

Answer 2

Coding study (prep)

Question 3

Method EXP2?

Answer 3

Lab exp using independent measures

Question 4

Procedure EXP1?

Answer 4

•suspect (later convicted of murder) videotapes during several hours of interview
-police had 2 eyewitness testimonies
-2 experienced officers present+his lawyer
-suspect denied involvement but later proved guilty
•6 fragments isolated+codes for 12 behaviours
(E.g gaze aversion, smiling, speech rate)

Question 5

Results EXP1?

Answer 5

• during pre-confession interviews: longer pauses, spoke slower, more speech disturbances than when telling truth
• in confession interview, showed similar patterns of behaviour
• appears when lying he had to think harder, telling truth he had to control behaviour

Question 6

Procedure EXP2?

Answer 6

•selected videotape fragments shown to 65 police officers who were asked after each:

1. Is he lying? (Yes or no)
2. Is he tense? (Likert scale 1-7)
3. Is he controlling his behaviour? (1-7)
4. Is he having to think hard? (1-7)

Question 7

What were the 2 IVs in EXP2?

Answer 7

• whether murderer lying or not in tape

* whether clips taken before or after confession

Question 8

Results EXP2?

Answer 8

• accuracy 64% (above level of chance+most deception studies)
• better at detecting truth (70%) than lies (57%)
• high individual differences (some based on stereotypes, some more perceptive)

Question 9

Conclusions?

Answer 9

• murderer contradicted stereotypical lying behaviours e.g nervousness
• murderer had been previously interviewed so possible d.c

Question 10

Strengths?

Answer 10

• lab exp= high control, standardised, cause+effect
• quantitative data
• high Eco validity

Question 11

Weaknesses?

Answer 11

• low Eco v as lab
• ethnocentric
• androcentrically biased
• small sample
• reductionist= irl have background info

Question 12

Aim?

Answer 12

To investigate the behaviour of a suspect telling lies during police interviews+to assess the accuracy of with which the police identify lies.