Detection of Deception - complete Flashcards
What is the nature of deception?
lying and deception is a deliberate act
What is the frequency of lying?
Occurs everyday
DePaulo et al. (1996) College students told 2 lies a day, community members told 1 lie a day
DePaulo et al. (1998) frequency of lying alters between spouses, close friends and strangers
Why do we tell lies?
Vrij (2008)
- Personal advantage
- Avoid punishment
- Make positive impression/protect themselves from embarrassment
- Make others appear better
- Social lies to ease social situations
1-3 = self preserving 4 = other oriented 5 = both
What types of lies are there?
DePaulo et al (1996)
Outright lies - lies in which the information conveyed is completely different or contradictory to that the deceiver believes is the truth
Exaggerations - lies in which the facts are overstated or information is conveyed that exceeds the truth
Subtle lies - involve literal truths designed to mislead
What are non-verbal cues to detect deception?
Vocal characteristics - speech hesitations, rate and pitch
Facial characteristics - smile, gaze and blinking
Body movements - hand movements, head movements and shifting positions
What are the 6 fundamental errors?
- Behaviours wrongly associated with lying
- Actual cues to lying lack understanding or ignored
- Assumed lie behaviours are same across people and situations
- Assumed certain behaviours increase during deception
- People tend to show overt suspicion when doubtful of a persons credibility making person nervous and may elicit behaviours (stereotypical with lying), masking actual cues
- Assumed that a statement is believed simply because its plausible and consistent
What are the three processes liars may experience?
- Emotions
- Cognitive complexity
- Controlling processes - processes are likely to lead to different behaviours
What is the Emotional Approach?
Ekman (1992) - Guilt, fear and excitement. The combination and strength of the emotions depend on the situation and the person.
Guilt - liar, morals, consequences
Fear - liar, person being lied to, high stakes
Excitement - person being lied to, additional onlookers
What is the Cognitive Complexity Approach?
Vrij et al (2008) - Lying is more cognitively demanding that telling the truth
Increased cognitive load leads to neglecting body language
More speech errors and pauses
Looking at the face of our conversation partner is too distracting
What is the Attempted Behavioural Control Approach?
Liars will attempt to control their behaviour in order to look like they are behaving normally (truthfully)
Over-control = leakage of clues such as increased gaze, lack of movement and smooth speech
What are the issues with these underlying processes?
All three processes (emotional approach etc.) may occur together and are not mutually exclusive
One process could be more prevalent than the other according to circumstances e.g. if the lie is complicated the liar will have to think harder than if the lie is easy
Explain the background to ‘micro-expressions’
Porter et al (2005) - deception can be achieved by altering displayed emotions
- simulated, masked, neutral
Ekman suggested that concealed emotions can manifest into micro-expressions that last 1/25 of a second
Its claimed that trained observers can spot these expressions
Explain what a Statement Validity Assessment is? (SVA)
Analyses verbal and written consent
Linguistic analysis of a persons testimony
Undeutsch (1967) hypothesised that descriptions of events that actually happened differ in content and quality from fictitious accounts
Used in Germany and Netherlands to assess credibility of children’s statements of sexual abuse
What does SVA consist of?
Structure interview
Criteria Based Content Analysis
Validity Checklist
What does a structure interview in a SVA consist of?
Ask questions to elicit further critical information
Structure the questions around interviewee’s understanding of events
Avoid susceptibility of children to leading questions
Bull(1998) a child’s description of past events are notably incomplete