Detection of Deception by Facial Expression

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Detection of Deceptionby Facial Expression

• Telling Lies
• By Paul Ekman W.V. Friesen
• Presenter Michael Roth

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Detecting Deceit

• No outright signs lead to deceit
• Gestures
• Facial expression
• Muscle twitch
• Emotions
• Sound of Voice
• Facial Expression
• Body Movement

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Why it is hard to detect lies

• Too much to consider
• Language (diction use)
• Pauses in speech
• Facial expression
• Posture
• Head movement
• Respiration
• Flushing
• Blanching
• Sweating

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What lie catchers look for

• Untrained lie catchers
• Words (processed quicker)
• Facial expression
• Trained lie catchers
• Words
• Facial expression
• Body movements
• Respiration
• Summarize how all factors lead to a lie

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Liars

• Words
• Can choose words carefully (easy deception)
• Facial Expression
• Do not realize facial expression until extreme
• Face directly connected to emotional areas in the
  brain.
• Sensations in the face (ignored)

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Facial Expression

• Voluntary
• Misleading expression
• Showing expression
• Varying success
• Involuntary
• No thought/intention involved
• Muscle fire
• Initial facial expression
• Deception leaks

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Facial Clues to Deceit

• Lying and truth can exist simultaneously
• Most people cannot detect a lie
• Felt
• False expressions
• Felt False expression found in a single blend
• Face
• What liar shows
• What liar conceals

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Facial clues cont.d

• Pyramidal Neural system damage
• Damage persons
• Cannot make facial expressions on command
• Cannot deceive
• Undamaged persons
• Can make facial expression on command, cannot
  make facial expressions on their own.
• Exceptional liars

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Pyramidal Nerve(s)
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What the face can show

• Which emotion is felt
• Anger, fear, sadness, disgust, distress,
  happiness, contempt, excitement, and surprise
• Blending of emotions
• Two emotions can be expressed at same time
• Strength of felt emotion
• Intensity
• Rage, terror, annoyance and apprehension

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Culture and age with respect to facial expression

• Involuntary facial expressions
• Same as seen in primates
• Universal facial expression
• Race
• Age (even in small children)
• Gender
• Culture

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Facial deception cont.d

• To detect a lie other systems of lie detection
  can be used to backup an accusation
• Voice
• Body movement
• Word choice
• More than facial lie detection should be used
  when confirming a lie (use one above in addition
  to facial expression)
• Facial expressions should be repeated

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Facial Deception Cont.dWhat to look for

• Facial symmetry
• Asymmetry neg. emotions
• Usually noticed
• Eyes
• Brow Lowering
• Reliable facial muscles
• ANS (autonomic nervous system)
• Timing
• Duration of facial expression
• Onset vs. offset
• 10 seconds or more false (felt expression are
  short not long)
• Long expressions are mock expressions

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Facial Deception Cont.dWhat to look for

• Expression after wording deception
• i.e. a fist bang should come before an outburst
  in order to be a true expression
• Synchronization
• Facial expression and body movement should be
  synchronized

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Most important Facial expression

• The smile
• 18 different kinds
• listener, enjoyable-fear, enjoyable-anger,
  dampened, miserable, enjoyable-sadness, felt
  (longest smile), contempt, flirtatious,
  enjoyable-surprise, qualifier, compliance,
  embarrassment, coordination, enjoyable-excitement,
  and Chaplin.
• Zygomatic muscle
• 1 muscle for enjoyment expression
• 1-3 for more complex expressions of enjoyment
• Moves cheekbones, lip corners, skin under eyes,
  skin around ears and tip of nose
• Produces crows feet wrinkles (eye corners)

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Zygomatic muscle
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Smiles cont.d

• False smiles
• Asymmetrical
• Involve muscles around the eyes
• No raised cheeks
• No crows feet
• No bags below the eyes
• Slow decline of smile stepped decrease
• No eyebrow movement
• Lower face appears as a normal smile, upper face
  does not, however forehead wrinkles may appear.

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Smile Example
Genuine Smile
False Smile
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Summary

• Most liars can fool people (untrained people)
• Children good liars at age 8
• Believing a liar vs. disbelieving a truthful
  person
• Friendships, job, life at stake when detecting
  deceit
• Individual differences among facial expression
• Absence of sign not evidence of truth
• Medical history of individual Should be read,
  before a lie detection test is given
• Watch for leakage

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References

• Ekaman, Paul Freisen, W.V. Telling Lies Clues
  to
• Deceit in the Marketplace, politics, and
  Marriage. Pp.80-190. W W Norton Company New
  York
• http//images.google.com/imgres?imgurlhttp//www.
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  Anatomy of the human body. Fig. 883. 3 Oct. 2006.
• The lie Detective. http//images.google.com/imgres
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  ial_s26sa3DG. 3 Oct. 2006. Paul Ekman shows a
  genuine smile, left, and a false smile, right.