The Art

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The Art Scienceof Lie Detection

• Laura Freberg, Ph.D.
• Professor of Psychology
• California Polytechnic State University, San Luis
  Obispo
• laura_at_laurafreberg.com

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Todays Agenda

• What is a lie?
• Why do people lie?
• When are they easy or hard to catch?
• How do people telegraph their truthfulness?
• What are the emerging technologies in lie
  detection?
• A quick video of body language during a lie

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What Is a Lie?

• According to the American Heritage Dictionary, a
  lie is
• 1. A false statement deliberately presented as
  being true a falsehood.
• 2. Something meant to deceive or give a wrong
  impression.
• Note the emphasis on the persons intent.

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Types of Lies

• Protective lies Telling children that the
  stork brought them because you dont think
  theyre old enough to talk about sex, or
  reassuring your relative that he/she is not
  really terminally ill
• White lies Lies that do no harm, and may do
  good, such as complimenting your hostess meal
  even if you didnt enjoy it much (social tact)
• Lying by omission Failing to reveal ones belief
  in order to deceive.
• Bluffing Usually considered more of a tactic
  than a lie, as it occurs in the well-understood
  context of a game.

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More Types of Lies.

• Jest When we use sarcasm or tell tall tales, we
  assume others understand we are deliberately not
  telling the truth.
• Careful Speaking Avoiding the telling of an
  outright lie with carefully chosen words a
  half-answer that is accurate but does not fully
  answer a question.

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The Morality of Lying

• Many philosophers (e.g. Kant, Thomas Aquinas)
  prohibited ALL lying, even if it meant death.
• Lying is a misuse of the human faculty of speech.
• Lying undermines trust, which is essential to the
  community.
• Lying undermines others Lying makes a decision
  for the other person, rather than letting him/her
  decide based on facts.
• Others defend lying, such as telling a Nazi
  soldier that one has no Jewish children in the
  house.

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Why Do We Lie?

• We are not alone. Deception is common in the
  animal kingdom. All animals (including us)
  deceive others to obtain benefits or avoid costs.

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Lying in Animals

• Koko, the female gorilla who uses American Sign
  Language, signed cat did it, when confronted
  with a sink she had damaged during a tantrum. It
  is not clear whether or not Koko was making a
  joke or lying.
• Wolves often bluff during ritual fighting that
  maintains the hierarchy within the pack.

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The Development of Lying

• The ability is universal.
• Children demonstrate Theory of Mind at about
  the age of 4 years. Simultaneously, they are
  capable of lying effectively.
• The ability to lie precedes a moral understanding
  about the importance of honesty. Consequently,
  children lie frequently until they learn that
  this results in negative consequences.
• Adults probably lie as frequently as children,
  but about different things.

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Even Robots Will Learn to Deceive

• Laurent Kellers robots react to theenvironment
  with a computerized genome.
• Bots that find food mate with other successful
  bots and send their genome into the next
  generation. Bots can turn blue lights on and
  off.
• Bots evolved the ability to communicate with
  lights. Some flashed their lights near food,
  while others flashed their lights near poison.
• Bots gave correct information to relatives,
  but flashed their lights far away from food when
  surrounded by strangers.

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Catching a Liar

• Liars will look different ONLY when the following
  two conditions are fully met
• The person is deliberately and knowingly telling
  a lie.
• The person thinks lying is wrong.

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Reconstructive Memory

• When we retrieve information from memory to use
  it, the data are at risk for change. The person
  retrieving changed, inaccurate information will
  believe that he/she is telling the truth.
• Elizabeth Loftus and Eyewitness Testimony
• Loftus (1975)
• N150
• Video of an automobile accident
• IV
• How fast was the white sports car going when it
  passed the barn while traveling along the
  country road?
• How fast was the white sports car going while
  traveling along the country road?
• DV measured one week later
• Did you see a barn?

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Loftus Results
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When People Dont Care.

• People who do not believe that lying is wrong
  will show few, if any, detectable signs of
  arousal.
• Psychopaths, criminal or not, are incapable of
  empathy or guilt. Therefore, they do not perceive
  that harming others is a problem, and will be
  effective liars.

15
Signs That a Person Is Lying

• Detecting lies in people you know is FAR easier
  than detecting lies in a stranger. When dealing
  with strangers, use baseline questions that
  nobody would lie about to establish normal
  behavior.
• Assuming a person is deliberately lying AND
  recognizes lying as negative, you may observe
  some/all of the following
• Reduced articulation
• Facial and body responses that do not match
• Facial and body responses that pass quickly are
  are replaced by more conscious responses

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More Signs of Lying

1. Reduced upper body movement
2. Increased lower body movement
3. Nervous smiling or laughter that is inappropriate
   given the topic under discussion (smiling is a
   submissive signalIm okay, dont hurt me)
4. Eye contact (works in the generic American
   culture, but few others)
5. Timing Emotions are spontaneous, instantaneous
   reactions to our environment. Any delay in
   reaction should be suspect.

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Traditional Lie Detector Tests

• Polygraph tests are reliable about 65 of the
  time, even when conducted by experts.
  Consequently, they are not admissible in court.

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Other Tech Efforts

• Truth serum
• Brain fingerprinting
• fMRI
• Brain activity during the processing of real
  memories and imagined events is identical.
• fMRI requires cooperation (no moving)
• Cannot detect lies by omission
• CAN detect if a person is thinking about a place
  versus a face
• CAN detect extra brain activity required by lying

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Other Challenges for fMRI

• Small number of participants
• Generally typical, law-abiding participants
  without psychopathology
• Can we generalize from the laboratory (no risk)
  to the courtroom (huge risk)?

Lying
Truth
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Ethics of New Technologies

• Technology generally moves much faster than
  corresponding discussions of ethics.
• What if we can read the brain? How should that
  be used? What protections should we have for
  participants?

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Thank you! Any Questions?

• Feel free to email me
• laura_at_laurafreberg.com
• Or
• visit me on the web at
• http//www.laurafreberg.com