Suspects, Lies, and Videotapes:

An Analysis of Authentic High Stake Liars

Samantha Mann, Aldert Vrij, and Ray Bull

external image interrogator.JPG

Background and Aims of the Study:

The behavior of liars has always been studies experimentally, in the laboratory. Most people think that increased fidgeting and decreased eye contact is proof that someone is lying. However, there has been no credible study done to show any connection between eye contact and lying.

Vrij and Mann (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 on high-stake liars tries to extend these findings to a study with a larger sample.

1) To determine if there is any association or systematic behavioral indicators to distinguish between those who are lying and those who are telling the truth.
2) To determine if cognitive load ( hypothetical construct used to describe the load of control of working memory) causes changes in behavior relevant to lying or telling the truth.

Participant Group:

The participant group included an opportunity sample of 16 police suspects (13 males and 3 females). These suspects included 4 juveniles (three 13 year-olds and 1 15 year-old) and 12 adults (under 65). 15 were Caucasian (English as a first language) and 1 Asian (Punjab first; fluent in English)

Crimes for such police suspects being interviewed for includes:
a) Theft (9)
b) Arson (2)
c) Attempted Rape
d) Murder (4)

Researchers asked police detectives at Kent County, UK PD to collect videotaped interviews in which they were involved and where the suspect had lied at first, then told the truth.

-Police found tapes where suspects lied but later told the truth (64 video clips)

Research Method:

The research method was a quasi-experiment, where the independent variable was not directly manipulated by the experimenter.

Independent Variable - Where the police suspect was lying or telling the truth.

Independent observers had to control and manipulate this in the collection of data.

Data Collection Process:

Observers collected data by watching an hour-long video, consisting of clips of 16 suspects telling truths and lies. They were then asked to analyze the content by producing quantitative data, which was often numerical, to simply detection of trends and to remove subjectivity.

Type of Data Collected:

Quantitative data was collected - Hour-long videotape consisting of clips of 16 suspects. The truths that were displayed were also comparable to the lies that the suspects made. I.E. The truth about their name was not comparable to a response to them committing murder.
Total of 27 truth/38 lies - 65 Total Clips that varied in length


Observers, not the suspects, were instructed to code the one hour video footage, also called content analysis. This is where they were asked to analyze and record quantitative, numerical data to remove subjectivity and increase detection of trends . They were not told the hypothesis or the nature of the clips, to enhance ignorance and deception. Once they coded the behaviors, they transformed into a manageable format so that the truths and the lies could easily be compared. The result was one truth-telling score and one lie telling score for each behavior of each participant.

Then, two observers were asked to independently code the behavior. After all of this collection of data, a Pearson correlation statistical test was used between the two independent observers and the others, which showed a strong consistency between the two codes. This means that there was no significant difference between the two coders.

Special/Equipment and Materials:

- Collected Interview Video Tapes of Criminal Suspects


Behaviors recorded:

  1. Gaze Aversion
  2. Blinking
  3. Pauses
  4. Head Movements
  5. Speech Disturbances (stuttering)

-Behavioral results for the 6 categories were not significantly different
-Noticeable differences were found between the hand and arm movements and pauses
-The deceptive group paused longer and blinked less but there were many individual differences

Note: Because they did not measure nor manipulate cognitive load and nervousness in this study, all conclusions are speculative.
This gives some support for the cognitive load process in explaining deceptive behavior as both long pauses and fewer blinking suggest and indicate to cognitive load.
However, because they did not manipulate or measure cognitive load and nervousness, all conclusions are speculative.

external image 6416802_f260.jpg