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Detection of Lies

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Title: Detection of Lies


1
Detection of Lies Deception
  • Thou shalt not bear false witness against thy
    neighbor. Ex. 2016
  • False words are not only evil in themselves, but
    they infect the soul with evil. Socrates

2
Defining Deception
  • Lies do not necessarily represent complete
    distortions of reality!
  • Mitchell (1986) Deception is a false
    communication that tends to benefit the
    communicator.
  • Krauss (1981)Deception is an act that is
    intended to foster in another person a belief or
    understanding with the deceiver considers to be
    false.

3
Defining Deception
  • Lies do not necessarily represent complete
    distortions of reality!

X X ACCIDENT
X X
4
Lying Everyday Social Interaction (DePaulo et
al. 1996)
  • People lied almost twice a day, lied to 34 of
    all interactions
  • Told fewer lies to people they felt emotionally
    closer
  • Told 1 lie in every 10 social interactions with
    spouses
  • Only 18 of the lies were detected by others
  • 83 would like to get a job (Heywood, 1998)
  • 90 wiling to lie to a prospective date

5
History of detection of deception
  • Trial by Combat (resolving issues through human
    strength)
  • Trial by Ordeal (based on religious beliefs, i.e.
    China, Middle East)
  • Trial by Torture (witch-hunts inquisition)
  • Trial by Jury (fact finders)

6
Concept of Lie Deception
  • Both psychological physiological phenomena play
    an important role in the truth finding process.
  • Physiological phenomenon occur as reactions to
    stress fear when we are under stress or
    serious threats, our autonomic nervous system
    will inhibit salivation and all digestive
    processes, and result in a dry mouth.
  • Others blood pressure, eye movement, breathing,
    sweating etc.
  • Freeze, fight or flight?

7
Scientific Advancements
  • Scientific Cradle (1890)
  • Galvanic Skin Response (GSR) (1897)
  • Polygraph instrument (1921)
  • Forensic assessment interview
  • Thermal images of the face (2002)
  • Biometrics

8
Fight or Flight or Freeze Response Mechanism
FIGHT
FLIGHT
FREEZE
9
GSR and Polygraph instrument
10
Why Do People Lie?
  • To serve self-interest and self-promotion
  • Social lies - to avoid awkward situations or
    discussion
  • Privacy concerns
  • Others?

11
Types of Lies
  • White lies (social conventions, reduce
    interpersonal conflicts, makes life easier
    sometimes by lying)
  • Intentionally harmful and self-serving lies (lie
    to evade responsibility/illegal acts, lie to
    defame or defraud others)
  • Lying by commission (fabricating information,
    active deceit, requires greater cognitive energy,
    i.E. Cant contradict prior information)
  • Lying by omission (this is a method of choice,
    involving less risk, simply concealing
    information so consider as passive deceit)

12
Non-verbal Behavior
  • Three categories Emblems, Illustrators
    Adaptors
  • Emotions - especially facial Expression
  • Six universal facial expressions of emotions
    Happiness, Sadness, Surprise, Anger, Fear and
    Disgust
  • Crucial - disjunction between verbal content and
    emotional display.
  • Play with emotions (www.do2learn.com)

13
Gender Differences
  • Male Self-oriented lies, to gain personal
    advantage (to make a positive impression on
    others)
  • Female Other-oriented lies (to protect others)
  • Other reasons?

14
Q Can we always accurately spot liars?
  • Manipulators, people who score high in social
    skills
  • Actors (more emotional control, ability to
    conceal true feelings)
  • Sociable People (extravert vs. introverts,
    socially anxious people tend to feel more
    comfortable telling the truth)
  • Adaptors (some people have special ways of coping
    with their insecurity by adapting themselves to
    others)

15
Liars may experience 3 different processes
(DePaulo, 1988)
  • 1.     The Emotional Approach
  • 2.     The Content Complexity Approach
  • 3.     Attempted Control Approach

16
2002 Class Experiment Accuracy in Judging
Deception
17
Guidelines for Detecting Deception (Aldert Vrij
2000)
  • Be suspicious
  • Probing
  • Do not reveal important information
  • Be informed (context personalities)
  • Ask liars to repeat what they have said before
  • Avoid abandon stereo-types
  • Compare liars behaviour with their natural
    behaviour - baseline.

18
Guidelines for Detection of Deception
  • Lies detectable via non-verbal cues if liar
    experiences fear, guilt or excitement (or high
    emotion) or if the lie is difficult to fabricate
  • Mismatches between speech content non-verbal
    behaviour
  • Deviation from normal or baseline behaviour
  • Judgement of lying only after other explanations
    have been negated
  • Encourage suspect to talk talk
  • Stereotyped ideas about cues to deception
    (avoidance of eye contact, fidgeting etc.) --
    individual differences are crucial

19
Non-verbal behaviours (Vrij 2000)
  • Vocal Characteristics
  • Speech hesitations
  • Speech errors
  • Pitch of voice
  • Speech rate
  • Latency period
  • Frequency of pauses
  • Pause duration

20
Non-verbal behaviours (Vrij 2000)
  • Facial Characteristics
  • Gaze
  • Smile
  • Blinking
  • Movements
  • Self-manipulations e.g. scratching/rubbing
  • Illustrators functional hand arm movements
  • Hand finger movement non-functional
  • Leg foot movement
  • Head movement nods shakes
  • Trunk movement or upper body e.g. shrugging
  • Shifting position re-arrangements of sitting
    position etc.

21
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