Cognitive-Mann (lying)

Question 1

Aim

Answer 1

To determine if there are systematic indicators to distinguish between those who are lying and those who are telling the truth

To determine if cognitive load causes changes in behavior relevant to lying

Question 2

Background

Answer 2

The behaviors of liars has typically been studied in a laboratory decreasing the ecological validity, as it is an odd task.

Typically people say that fidgeting and decrease eye contact are products of lying

Question 3

Past Study

Answer 3

2001-Differences between lying in ‘real life settings’ & lying in an ‘experimental situation’ led to examining videotape of a murder in police custody.

This study extend the finding with a larger sample

Question 4

Cognitive Load

Answer 4

during complex mental activities amount of information & interactions that must be processed can cause an under/over load of the working memory.

Question 5

Sample

Answer 5

This was a self selecting sample, and an opportunity sample with 16 police suspects (13 males & 3 females) (4 juveniles 3=13, 1=15, the rest were adults under 65) (15 Caucasian & 1 Asian)

The crimes were 9 theft, 2 arson, 4 murder, 1 attempted rape

10 participants had been known to the police 7 had been interviewed about other crimes

Question 6

Method

Answer 6

A natural experiment with ‘naturalistic’ observation because the participant did not know their behavior would be analyzed for a psychological study

The design was repeated measures because the participant participated in both parts of the independent variable

Question 7

Independent Variable

Answer 7

The ‘truth’ or the ‘lie’

It was a quasi experiment because the researcher did not manipulate the IV. It was the choice of the suspect whether to lie or tell the truth, but the IV could be said to be a truth or lie

Question 8

Dependent Variable

Answer 8

the behavior shown by the suspects on the videotape, which was observed and categorized

Question 9

Apparatus

Answer 9

A 1-hour videotape with 65 clips of the 16 suspects. Of the 65 clips 27 of them were truths and 38 were lies. Each subject had between 2 and 8 clips, varying in length

Coding scheme/response categories on which the observers could record their observations

Question 10

Controls

Answer 10

The researchers (Mann et al.) did not code the video clips because they may have been biased and ‘seen what they wanted to see’.

The suspects truth and lies were confirmed by the police and because suspects later confessed and admitted the lies.

The observers were not told what the study was about. They did not know whether a statement was a true or false. They merely recorded the number of times each of the eight target behaviors occurred.

Question 11

Behaviors Recorded

Answer 11

Gaze Aversion, Blinking, head movements, speech disturbances, pauses, hand/arm movement,

Question 12

Procedure (4 parts)

Answer 12

1. Video tapes of authentic liars from police records were obtained. Clips were broken down so there was at least one truth and one lie per participant and a final tape was created.
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 video footage’.
3. Observer 2 watched a random sample of 36 clips (at least one of each suspect) rather than all clips.
4. Checks were done to see if there was good agreement (inter-rater reliability).

Question 13

Coders

Answer 13

Observers were instructed to ‘code the video footage’ – Content analysis (studying the content of communication while collecting quantitative data)

Inter-rater reliability between the two coders was excellent.

A Pearson correlation statistical test was used to analyze the observations on a scale of 0 (no agreement) to 1 (perfect agreement).

Question 14

Results

Answer 14

quantitative data

There was no behavior that all liars exhibited, making generalization a problem.

The most reliable indicators of lying were blinking and pauses, where the majority of participants paused longer (81%) and blinked less (81%) while lying

Question 15

Conclusion

Answer 15

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 lying are pausing for longer and blinking less.

Gives some support for the cognitive load process in explaining deceptive behavior, as both fewer blinking and longer pauses are possible indicators of cognitive load

However, because they did not measure nor manipulate cognitive load and nervousness in this study, all conclusions are speculative

Question 16

Strengths

Answer 16

High ecological validity

Inter rater reliability and single blind study

quantitavie data

Question 17

Limitations

Answer 17

Different Interviews used for different participants, and occasionally more than one interviewer

Small sample of only 16 people