Detection of Lies

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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

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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.

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Defining Deception

• Lies do not necessarily represent complete
  distortions of reality!

X X ACCIDENT
X X
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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

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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)

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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?

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Scientific Advancements

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

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Fight or Flight or Freeze Response Mechanism
FIGHT
FLIGHT
FREEZE
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GSR and Polygraph instrument
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Why Do People Lie?

• To serve self-interest and self-promotion
• Social lies - to avoid awkward situations or
  discussion
• Privacy concerns
• Others?

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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)

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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)

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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?

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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)

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Liars may experience 3 different processes
(DePaulo, 1988)

• 1.     The Emotional Approach
• 2.     The Content Complexity Approach
• 3.     Attempted Control Approach

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2002 Class Experiment Accuracy in Judging
Deception
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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.

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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

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Non-verbal behaviours (Vrij 2000)

• Vocal Characteristics
• Speech hesitations
• Speech errors
• Pitch of voice
• Speech rate
• Latency period
• Frequency of pauses
• Pause duration

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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.

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