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1. RGB 1 Detection of Lies & Deception ?Thou shalt not bear false witness against thy neighbor.? Ex. 20:16
?False words are not only evil in themselves, but they infect the soul with evil.? Socrates
2. RGB 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. RGB 3 Defining Deception Lies do not necessarily represent complete distortions of reality!
4. RGB 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 recorded the Social Interactions of College Students and Found That:recorded the Social Interactions of College Students and Found That:
5. RGB 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) Truth unless proved otherwise beyond reasonable doubt banning of Truth serums = torture US supreme courtTruth unless proved otherwise beyond reasonable doubt banning of Truth serums = torture US supreme court
6. RGB 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. RGB 7 Scientific Advancements Scientific Cradle (1890)
Galvanic Skin Response (GSR) (1897)
Polygraph instrument (1921)
Forensic assessment interview
Thermal images of the face (2002)
Dr. Angelo Mosso -- physiologist studying the effect of fear on the cardiovascular and respiratory systems
GSR -- discovered by Harold Sticker in 1987 a pyschologist who measured changes in sweat gland activities. Thermal imaging ?blood flow around the eyes see also ?brain fingerprinting? - electric voltage when memory is triggered so called p.300 response.Dr. Angelo Mosso -- physiologist studying the effect of fear on the cardiovascular and respiratory systems
GSR -- discovered by Harold Sticker in 1987 a pyschologist who measured changes in sweat gland activities. Thermal imaging ?blood flow around the eyes see also ?brain fingerprinting? - electric voltage when memory is triggered so called p.300 response.
8. RGB 8 Fight or Flight or Freeze Response Mechanism
9. RGB 9 GSR and Polygraph instrument
10. RGB 10 Why Do People Lie? To serve self-interest and self-promotion
Social lies - to avoid awkward situations or discussion
11. RGB 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. Can?t contradict prior information)
Lying by omission (this is a method of choice, involving less risk, simply concealing information so consider as passive deceit)
12. RGB 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. RGB 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)
14. RGB 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. RGB 15 Liars may experience 3 different processes (DePaulo, 1988): 1.?????The Emotional Approach
2.?????The Content Complexity Approach
3.?????Attempted Control Approach
16. RGB 16 2002 Class Experiment: Accuracy in Judging Deception
17. RGB 17 Guidelines for Detecting Deception (Aldert Vrij 2000) Be suspicious
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. RGB 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. RGB 19 Non-verbal behaviours (Vrij 2000) Vocal Characteristics
Pitch of voice
Frequency of pauses
20. RGB 20 Non-verbal behaviours (Vrij 2000) Facial Characteristics
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. 21 Cautions: the othello error & idiosyncracy errorCautions: the othello error & idiosyncracy error