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Mann - Suspects, Lies, and Videotape: An Analysis of Authentic High-Stakes Liars
Terms in this set (15)
Liars are said to avoid eye contact and show signs of fidgeting such as touching their face, playing with objects and putting a hand over their eyes of mouth. Research shows these things to be wrong because research into lying is usually done artificially in a laboratory, with actors telling lies that are not important and have no consequences; where they have no guilt and they know they are being videotaped. What is needed is a study of 'real' people telling lies that matter, with Major consequences if they are found out. In other words, a study of authentic high-stakes liars is needed.
To conduct a study examining the behavior of liars in very high-stakes situations - real people in police custody who are telling genuine lies (along with some truths). Based on research, it is expected that liars will make fewer movements, show an increase in speech disturbances, with longer pauses, and blink their eyes less.
Natural experiment with 'naturalistic' observation because the participants did not know their behavior would be analysed for a psychological study.
The researchers did not manipulate an IV. It was the choice of a suspect whether to tell a lie of the truth, but the IV could be said to be a truth or a lie. The dependent measure was the behavior shown by the suspects on the videotape, which was observed and categorized.
As the IV was 'truth' or 'lie' and as all participants told both 'truths' and 'lies,' the design was repeated measures.
observation coding/response categories
The two observers were told to 'code the video footage'. They were not told what the study was about or that truths and lies were involved. They had to code (mark on a sheet if a behavior happened) 8 different behaviors: gaze aversion, blinking, head or finder movements, speech disturbances and pauses. At the end of the tape it could be determined which behaviors happened the most and whether these were during the telling of a lie or truth (which the experimenters knew, but not the observers).
participants and sampling technique
16 police suspects (13 male and 3 female) aged between 13 and 65. Suspected crimes included murder, attempted rape, theft and arson Interviews with suspects had been videotaped by Kent police and the tapes were used in the study. The sample was self-selecting because the suspects were known to have made both truth and lie statements. Lies were known to have made both truth and lie statements. Lies were known because the suspects later confessed to the crimes.
Mann et al. set up the study and then analyzed the results. the coding of the video clips was done by the two naive observers.
A 1-hour videotape with 65 clips of the 16 suspects. Of the 65 clips 27 were truths and 38 were lies. Each suspect had between 2 and 8 clips; each clip lasted between 41 and 368 seconds.
Coding scheme/scheme/response categories on which the observers could record their observations.
The researchers did not code the video clips because they may have been biased and 'seen what they wanted to see'.
The suspects' truths and lies were confirmed by police and because the suspects later confessed and admitted lies.
The observers were not told what the study was about. They did not know whether a statement was true or false. They merely recorded the number of times each of the 8 target behaviors occurred.
1. Video tapes of authentication liars from police records were obtained. Clips were broken down so there was at least one truth and one lie per participant. A final tape was created, lasting 1 hour.
2. Observer 1 watched the videotape, coding (recording if a behavior happened) the 8 behaviors in the response categories. The observer was told nothing more than to 'code the the video footage'.
3. Observer 2 watched a random sample of 36 clips (at least one of each suspect) rather than all the clips.
4. Checks were done to see if there was good agreement (inter-rater reliability).
It was excellent between the two observers was excellent. Observations were analyzed with a correlation test (Pearson product-moment test) with correlations on a scale of 0 (no agreement) to 1 (perfect agreement). Agreement was: gaze aversion 0.86, blinking 0.99, head movements 0.95, self-manipulation 0.99, illustrators 0.99, hand/finger movements 0.99, speech disturbances 0.97, and pauses 0.55.
Qualitative data were gathered; each time a target behavior occurred a mark was placed on the tally chart or sheet of response categories. The 8 categories were: gave aversion, blinking, head movements, self-manipulations, illustrators, Hand/finger movements, speech disturbances and pauses. Observations were converted to give a truth telling score and a lie telling score for each participant.
There was no behavior that all liars exhibited. This means that there were many individual differences, making generalization problematic.
No difference was found for head movements and speech disturbances, with 50% of suspects showing an increase and 50% a decrease when lying.
No difference was found for gaze aversion, with 56% showing more gaze aversion and 44% showing less gaze aversion while lying.
More participants (69%) showed a decrease than an increase (31%) in hand and arm movements during lying.
The most reliable indicators of lying were blinking and pauses, where the majority of participants paused longer (81%) and blinked less (81%) while lying. Both these showed significance levels of p<0.05 between lying and truth telling.
These findings contradict the popular belief that liars behave nervously by fidgeting and by avoiding eye contact. They confirm the hypotheses and it can be concluded that the most reliable indicators of telling a lie are pausing for longer and blinking less.
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