FL8 - Lies and the detection of deception

Question 1

What is the definition of deception?

Answer 1

“A successful or unsuccessful deliberate attempt, without forewarning, to create in another a belief which the communicator considers to be untrue” (Vrij, 2000)

Question 2

What are the types of lies?

Answer 2

• Outright lies
• Exaggerations (Exaggerating remorse for better sentencing)
• Subtle lies (To suit your narrative and omitting details)

Question 2

What are the reasons to lie?

Answer 2

• Self-orientated lies
• Other orientated lies

OR

• To gain personal advantage
• To avoid punishment
• To make a positive impression
• To protect themselves from embarrassment/disapproval
• For the safe of the social relationship
• (Vrij, 2000)

Question 3

What is the frequency of lying in the personality and gender of liars?

Answer 3

• American diary studies:
  
  • College students told 2 lie(s)/day
  • Community members told 1 lie/day.
  • Most lies were self-serving (DePaulo, 1996)
  • Frequency of lying depends on:

1. Personality and gender of the liars

• Extroverts lie more than introverts (to potentially make more friends)
• Frequency of lies similar between men and women
• Women tell more social lies (e.g. women about image and men about earnings)
• When dating:
  
  • women lie to improve physical appearance
  • men lie to exaggerate earning potential

Question 3

What is the frequency of lying depending on the situation in which the lie is told?

Answer 3

• 90% of people lie to get a date
• 83% of people lie to get a job

Question 4

What is the frequency of lying depending on the people who the lie is told to?

Answer 4

• Lowest rate of lying with spouses (1/10 interactions – mostly subtle)
• Highest rate of lying with strangers
• College students lie frequently to their mothers (almost 50% of conversations!)

Question 5

What are the three ways to catch of a liar?

Answer 5

1. Examine their physiological responses*
2. Observe their verbal and nonverbal behaviour
3. Analyse the content of what they saw

Question 6

How do we examine physiological response?

Answer 6

• Polygraphs measure physiological change not lies.
  
  • Blood pressure
  • Heart rate
  • Respiration
  • Sweating (GSR)
  • Not that good at detected lies

Question 7

What are the different behavioural indicators of deception?

Answer 7

• Some verbal and nonverbal cues are more likely to occur during deception than others, depending on:
  1. Emotion evoked
  • Deception results in different emotions (Ekman, 1985):
    
    • Guilt
    • Fear
    • Excitement (duping delight)
    • The strength of the emotion depends on the personality of the liar and the circumstances of the lie
    • Assumption: Emotions may influence the liars non-verbal behaviour and betray the liar
  2. Cognitive and content complexity
  • Lying is difficult to do - is cognitively demanding so more cues such as filler words or avoiding eye contact
  • Assumption: People engaged in cognitively complex tasks exhibit different nonverbal behaviours that may betray the liar (Vrij, 2017)
  3. Attempted behavioural control
  • Liars may attempt to control their behaviour to avoid getting caught
  • When liars do this, they sometimes overcontrol themselves, resulting in behaviour that looks rehearsed and rigid, and speech that sounds too smooth
  • Nonverbal behaviour is more difficult to control than verbal behaviour
    
    • Verbal cues:
      1. Higher pitch of voice
      2. Increased response latency
      3. Increased errors in speech
      4. Shorter length of description
    • Nonverbal Cues:
      5. Decreased nodding
      6. Decreased foot and leg movements
      7. Decreased hand movements
  • Micro-expressions
    
    • A fleeting facial expression discordant with the expressed emotion and usually suppressed within 1-5 to 1-25 of a second
    • It is difficult to control facial communication and it can betray a deceiver’s true emotion to a trained observer (Ekman, 1992)
    • Inconsistent emotional leakage occurred in 100% of participants at least once. Negative emotions were more difficult to falsify than happiness (Porter & ten Brinke, 2008)
      
      • In a high stakes scenario are more likely to occur. Inconsistent emotional leakage on top half of face occurs more frequently. Negative emotions were more difficult to falsify than happiness (ten Brinke & Porter, 2012a, b; Porter, ten Brinke, Wallace, 2012)
      • Usage is limited as most reliable identification of micro-expressions is through video coding and not in real time.
      • Training of people to see micro-expressions have rendered mixed, but poor results.
      • Emotional leakage by the eyes and the moutch
• There are cue-based theories as to why this occurs.
  1. Ekman’s emotional leakage theory
  2. Zuckerman’s four factor theory

Question 8

Can we actually use behavioural cues to detect deception?

Answer 8

• DePaulo et al. (2003) examined 158 cues to deception:
  
  • Liars are less forthcoming
  • Liars tell less compelling tales
  • Liars are less positive and pleasant
  • Liars are more tense
  • Liars include fewer ordinary imperfections and unusual details
• However, many behaviours showed no discernable links, or only weak links, to deception.
• Many of the ones that do show links are the verbal-cues. Also, no clear cut-off points or profile for lies and liars.

Question 9

How are content indicators of deception measured?

Answer 9

• Examining the content of the story
• Statement validity assessment (SVA; Vrij, 2005)
  
  • Developed in Germany to determine the credibility of child witnesses’ testimonies in trials for sexual offences.
  • Extended to adults and other types of cases.
  • The approach has been accepted in some European Courts, but not UK Courts; and is divided in the United States.
  • ## The main use of this technique is to guide police investigations and decisions of prosecutors

Question 10

What are the three parts of content indicators of deception? (name only)

Answer 10

1. Semi-structured interview
2. Criteria-based content analysis (CBCA) of transcribed statements given during the interview
3. Evaluation of CBCA by a set of questions (validity check-list)

Question 11

What is the criteria based content analysis of transcribed statements stage?

Answer 11

1. Trained evaluators judge the presence or absence (or strength) of 19 criteria
2. The presence of each criterion strengthens the hypothesis that the account is based on genuine experience
   
   • Based on the “Undeutsch hypothesis”:
   • A statement derived from memory of an actual experience differs in content and quality from a statement based on invention and fantasy (Undeutsch, 1987).
     - 5 categories of criteria
   General Characteristics
   1. Logical structure
   2. Unstructured production - Liars think you can’t change your story
   3. Quantity of details
   Specific Contents
   1. Contextual embedding
   2. Descriptions of interactions
   3. Reproductions of conversation - Deceptive accounts don’t reproduce these details
   4. Unexpected complications during the incident
   Peculiarities of Content
   8. Unusual details
   9. Superfluous details (things that are out of the ordinary are often indicators of truth)
   10. Accurately reported details misunderstood (don’t have the knowledge of what happened to describe, e.g. in child sexual assault)
   11. Related external associations
   12. Accounts of subjective mental state
   13. Attribution of perpetrator’s mental state
   Motivation-Related Content
   14. Spontaneous corrections - Common in truthful accounts
   15. Admitting lack of memory
   16. Raising doubts about testimony
   17. Self-deprecation (e.g. I’m so dumb, I just can’t remember)
   18. Pardoning the perpetrator
   Offence-Specific Elements
   19. Details characteristic of the offence (Is it consistent?\0

• Content Analysis - Why might criteria not be present?
  
  • Lack of imagination in inventing relevant characteristics
  • Do not realise judgements based on these characteristics, so don’t include them
  • Lack knowledge to incorporate certain criteria
  • Difficult to incorporate some criteria
  • Wary of including details in case they forget
  • Wary of including details that can be checked
  • Wary of including certain characteristics in case their stories sound less credible

Question 12

What is the evaluation stage of CBCA by a set of questions stage?

Answer 12

• To standardise CBCA findings, evaluators consider alternative interpretations
  
  • Psychological characteristics (age, verbal and social skills)
  • Interview characteristics (types of questioning)
  • Motivation to report (specific things or not)
  • Investigative questions (consistency with other evidence)

Question 13

Does CBCA criteria indicate deception?

Answer 13

• Criterion 3: in 80% of studies truth tellers included more details
• Criteria 4 and 6: in 69% of studies truth tellers included more contextual embedding and reproductions of conversation
• Cognitive criteria (1-13) received more support than motivational criteria (14-18)
• Vrij (2005) reviewed 37 experimental and field studies on CBCA Field studies:
  
  • Statements made by persons in actual cases of alleged sexual abuse
  • Clear forensic relevance, but difficult to establish ground truth
• Experimental studies:
  
  • Statements of participants who lied or told the truth for the experiment
  • Easy to establish veracity of statement, but differ from real-life situations
  • In 92% of experimental studies, truth tellers received higher CBCA scores than liars
  • For experimental studies, Vrij (2005) reported:
    
    • Overall accuracy of 55%-90%
    • Accuracy for truths of 53%-91%
    • Accuracy for lies of 35%-100%
  • Truth bias: CBCA is “truth verifying method” not “lie-detection technique”
  • The absence of criteria does not necessarily mean the statement is fabricated (Vrij, 2005)

Question 14

What are the concerns about SVA?

Answer 14

• No formal decision rules, profiles for truth or deception, or cut points
• Criteria should be given different weight (Sporer)
• Different types of lies (from subtle to outright) may yield different levels/kinds of characteristics
• SVA assessments are subjective and inter-rater reliability can be low, even after extensive training
• CBCA assessments of written statements are time-consuming & even training may not improve accuracy (Akehurst et al., 2004)

Question 15

Should we use CBCA?

Answer 15

• Chance rate = 50%
• Memon, Vrij, & Bull (2003) conducted a meta-analysis
• Nonverbal behaviour: Average scores of 9 studies of 9 studies (mostly lab studies)
• CBCA: Based on 13 lab studies
• Recent evidence suggests that higher accuracy rates by combining nonverbal and CBCA

Question 16

Why is it difficult to catch liars/methods not be good?

Answer 16

• Lie detection is difficult and there is no give-away cue
• Othello Error: Truth tellers may show similar behaviour to liars because they, too, may experience emotions, may have to think hard, or may have to control themselves.
• Adequate comparisons between truth-telling and lie-telling are not made (e.g., small talk vs. Interrogation).
• Observers seem to have incorrect beliefs about how liars behave and people, including police officers, are taught wrong cues
• Liars can use countermeasures (e.g., can train themselves to beat techniques).
• Deception research is often conducted in university labs and the stakes aren’t high enough. It’s hard to establish ground truth in field studies.
• The Brokaw hazard: Individual differences in emotional expression, vocal and body movement characteristics.
• Individual differences in ability to control: Some people are ‘natural liars’, or have trained themselves to be very effective liars.
• Cultural differences in nonverbal behaviour - e.g. eye contact to authority figures in some cultures may be considered disrespectful

Question 16

What is an overall approach to detecting deception?

Answer 16

• Combine CBCA and non-verbal behaviours
• If focusing on verbal and nonverbal (Vrij, 2000):
  
  • Be suspicious – put aside your truth (or lie) bias
  • Probe – keep on asking questions
  • Do not reveal important information
  • Be informed
  • Ask liars to repeat what they have said before
  • Watch and listen carefully and abandon stereotypes
  • Compare liars’ behaviour with their natural behaviour
• Apply a framework:
  
  • Behaviour (verbal and nonverbal)
  • Content of conversation
  • Context
  • Why