Vrij and Mann 2001 - Interviewing suspects - lie detection

Question 1

Aim

Answer 1

To investigate the behaviour of a suspect telling lies during a police interview and to assess the accuracy of which the police identify lies.

Question 2

Sample

Answer 2

Interviewee who was a convicted criminal

65 police officers (59 male, 6 female) from west sussex

Question 3

procedure 1

Answer 3

A suspect (later convicted of murder) was videoed whilst being interviewed. he denied involvement. 2 weeks later DNA evidence made him confess. tapes were analysed and coded for 12 behaviours.

during pre confessional interview there was longer pauses, slower speech. when lying he had to think about his answers longer.

Question 4

procedure 2

Answer 4

Lab study - 65 police officers shown the tapes and asked:

is he lying?
is he tense?
is he controlling his behaviour?
is he having to think hard?

After questions they wrote down what behavioural cues prompted their answers.

Question 5

results

Answer 5

overall accuracy - 64%
officers better at detecting truth than lies (70% vs 57%)
large individual differences

Question 6

Conclusion

Answer 6

the offender contradicted the widespread belief that liars behave in a nervous manor.
Police officers are much better at judging truths than lies