13 - Lie Detection Flashcards
What is deception?
A successful or unsuccessful DELIBERATE attempt, without forewarning, to create in another a belief which the COMMUNICATOR considers to be untrue
Comes from perspective of deceiever
Involves two people
What are the three types of lies?
Outright
Exaggerations
Subtle
What are 5 main reasons to lie?
To gain personal advantage
To avoid punishment
To make a positive impression on others
To protect themselves from embarrassment/disapproval
For the sake of social relationships (e.g. mother taking blame for son)
What does the frequency of lying depend on?
Personality & Gender of Liar
- extroverts > introverts
- m&f similar, but different lies (women social, men earning)
Situation in Which Lie is Told
- 90% to get prospective date, 83% lie to get job
People to Whom the Lie is Told
- lowest with spouses, highest with strangers
Overall, what are three things that can catch liars out?
Observe their verbal and nonverbal behaviour
Analyse the content of what they say
Examine their physiological responses
What are the behavioural indicators of deception?
Emotion
- deception results in different emotions, strength depends on liar’s personality and lie’s circumstances.
- may influence NVB (guilt -> avert gaze)
- but sometimes exhibit this NVB when not deceiving
Content Complexity
- lying is difficult, but so can some truths
- different NVB occur; more speech fillers, pause more, move limbs less, avert gaze
Attempted Behavioural Control
- liars might modify their behaciour to avoid getting caught (look into eyes, stop fidgeting)
- sometimes overcontrol, and become rigid
Micro-expressions
What are some verbal cues to lying?
Higher pitch of voice
Increased response latency
Increased errors in speech
Shorter length of description
What are some nonverbal cues to lying?
Decreased nodding
Decreased foot and leg movements
Decreased hand movements
What are micro-expressions?
Behavioural indicator of deception
A fleeting facial expression discordant with the expressed emotion, and usually suppressed within 1/5 to 1/25 of a second.
What can measure content indicators of deception?
Statement Validity Assessment (SVA)
What is a statement validity assessment?
Determines credibility of witness testimony.
Started with child witness’s in sexual offences trials.
Contains three elements;
- Semi-structured interview
- Criteria-based content analysis of transcribed version of statement given during the interview
- Evaluation of the CBCA outcome via a set of questions (Validity check list)
Describe the Criterion-Based Content Analysis in SVA’s
Trained evaluators judge presecne or absence (or strength) of 19 criteria in a statement derived from memory of actual experience. Determines if it differs in content and quality from a statement based on invention and fantasy.
Presence of criterion GENERALLY means truth. Crtieria of: - General characteristics - Specific contents - Motivation content - Offence Specific Elements
What are the criteria of general characteristics within the CBCA?
Logical structure
Unstructured production
Quantity of details
What are the criteria of specific contents within the CBCA?
Contextual embedding Descriptions of interactions Reproductions of conversation Unexpected complications Unusual details Superfluous details Accurately reported details misunderstood Related external associations Accounts of subjective mental state Attribution of perpetrator's mental state
What are the criteria of the motivation-related content within the CBCA?
Spontaneous corrections Admitting lack of memory Raising doubts about testimony Self-deprecation Pardoning the perpetrator
What are the criteria of general characteristics within the CBCA?
Describe characteristics of the offence
Why are the CBCA criteria absent in lies?
Lack of imagination in inventing relevant characteristics
Do not realise judgements based on these characteristics, so don’t include them
Lack of knowledge to incorporate certain criteria
Difficult to incorporate some criteria
Wary of including details in case they forget, that can be checked
In terms of the validity check list of CBCA, what is involved?
Evaluators consider alternative interpretations
- Psychological characteristics (age, social skills)
- Interview characteristics (type of questioning)
- Motivation to report
- Investigative questions
What does the experimental evidence about SVA suggest?
Criterion 3 received most support; quantity of details
4 and 6 also received strong support (contextual embedding and reproductions of conversations)
Cognitive criteria (1-13) received more support than motivational (14-18)
Overall accuracy; 55-90%
Accuracy for truths 53-91%
Accuracy for lies 35-100%
Truth verification method
What are some concerns about SVA?
No formal decision rules, profiles for truth or deception, or cut points
Criterion should be given different weight
Different types of lies may yield different levels/kinds of characteristics
SVA assessments are subjective and inter-rater reliability can be low, even after extensive training
CBCA assessments are time-consuming
In DePaulos (2003) study what did they find in terms of cues to deception?
Liars are less forthcoming Liars tell less compelling tales Liars are less positive and pleasant Liars are more tense Lies include less ordinary imperfections and unusual details
What are some of the difficulties in detecting deception?
Cultural differences in NVB
Individual differences in ability to control: some people are natural liars
Bokaw Hazard: individual differences in emotional expression, vocal and body movement characteristics
Deception research often conducted in research labs.
