Lie Detection

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Lie Detection
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• History of Lie Detection
• Current Methods
• What is the validity of lie detectors?
• Legal Issues
• Can you beat a lie detector?
• How to tell when someone is lying
• How to lie

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History of Lie Detection

• Greeks would ask questions and feel the
  subjects pulse.
• Torture as a means of interrogation
• Romans used crucifixion.
• Strappado was a means of medieval inquisition
  torture which would dislocate joints. The rack
  would stretch the victims joints to breaking
  point. Red hot pinchers would be applied
• Modern Leave a victim with no visible damage.
• In 1948, following the horrific abuses of World
  War II, the General Assembly of the United
  Nations inserted the prohibition against torture
  in the landmark Universal Declaration of Human
  Rights. Article 5 states "No one shall be
  subjected to torture or to cruel, inhuman or
  degrading treatment or punishment." The
  prohibition against torture is well established
  under customary international law as
• jus cogens.
• The Supreme Court in 1963 ruled that a confession
  extracted under truth serum drugs such as
  sodium pentothal, sodium amytal, and scopolamine
  - violated a defendant's constitutional right
  against self-incrimination.
• Should torture/ truth serum be permitted if its
  use would save lives or benefit society?

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Current Methods

• Modern polygraphy uses physiological changes in
  the peripheral nervous system (PNS) measure
  deception
• 1. Skin conductance changes (sweating)
• Blood pressure
• Respiration
• Heart rate
• Facial Micro-expressions (developed by Paul
  Ekman)
• It would have the advantage of not requiring any
  obvious intervention with the subject. Could be
  used secretively by videotaping.
• Neurotechnological Lie Detection (NTLD)
• Measurements of blood flow or electrical impulses
  in the brain to identify distinct indicators of
  deceptive communication.
• Measure lying more directly by measuring brain
  activity rather than second-order indicators like
  pulse or respiration.
• Advantages over polygraph testing
• Fear or other strong emotions may affect
  physiological responses and thus may confound the
  data in polygraphy.
• Polygraphy requires trained experts to read the
  graphs, while NTLDs would only require computers.
  
• Does this mean that NTLDs are reliable evidence
  in court?

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Two categories of NTLD

• Blood Flow Patterns
• By studying blood flow patterns during deception
  and comparing them to blood flow patterns during
  non-deception in similar situations, researchers
  can learn which regions of the brain are
  activated when people are lying.
• Functioning Magnetic Resonance Imaging (fMRI) is
  currently the most commonly used method for
  measuring blood flow in the brain. Images are
  constructed based on blood-oxygenation-level
  dependent (BOLD) contrast. When a brain region is
  more metabolically active, there is a local
  increase in MR signal or BOLD contrast. When
  people lie, the anterior cingulate cortex is
  activated. No Lie MRI started offering its
  fMRI-based lie detection services in 2006.
• Near-infrared spectroscopy (NIRS) focuses on
  activity in the prefrontal cortex and provides a
  way to measure changes in blood flow without the
  complex apparatus of an MRI machine. The basis of
  the technology is the measurement of how near
  infrared light is scattered or absorbed by
  various materials. Small devices are attached to
  the subjects skull, which shine near-infrared
  light through the skull and into the brain. This
  scattered laser light is picked up by sensors on
  the subjects skull. The pattern of scattering
  reveals the pattern of blood flow through the
  outer regions of the brain.
• Thermal imaging When people lie their eyes give
  off more heat.

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• Patterns of Recognition
• Use event related potentials (ERPs) through
  electroencephalogram (EEG) to identify patterns
  of recognition for the wave pattern of the P300
  wave. With EEG, the researcher uses electrodes
  placed on the subjects scalp to detect and
  measure patterns of electrical activity emanating
  from the brain.
• Brain fingerprinting attempts to discern
  whether a person has knowledge of a particular
  event or an image stored in his brain. The P300
  wave occurs when a subject recognizes information
  or a familiar stimulus. It is the only technique
  considered for admission into evidence.

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Is this ethical?

• Because these methods rely on correlations to
  determine lies, are they reliable?
• Should personal privacy be sacrificed for the
  better of society because NTLDs could serve
  forensic, security, and military purposes? Is
  personal privacy even being invaded?
• What about the self-incrimination clause of the
  Fifth Amendment that states that no person shall
  be compelled in any criminal case to be a witness
  against himself?
• Garnering the evidence vs. entering the
  suspects mind is violating
• Brain imaging and brain fingerprinting require
  clear testimonial response from the suspect, such
  as pressing a button. Is this the same as blood
  or hand writing samples used to solve a crime?
• Previously, in order for the contents of a
  persons mind to be exposed, he had to
  communicate that content actively, whether by
  speaking, writing, gesticulating, or some other
  deliberate means. Is this still considered
  communicating?

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What is the validity of lie detectors?

• United States v. Scheffer (1998)
• A host of studies show that polygraph testing
  shows 85 to 90 accuracy while critics state
  that it is 70.
• More likely to show innocent people guilty than
  vice versa.
• 1. False positive
• Leads to an incorrect accusation against
  the communicator. These may be more serious than
  false negative.
• 2. False Negative
• The "liar" gets away with the lie. This has
  been the traditional focus
• for assessment of the accuracy of a
  communication.
• Polygraph tests can discriminate lying from
  truth telling at rates well above chance but well
  below perfection.
• Hence, for the control question theory to be
  valid, two assumptions must hold. The first
  requires innocent individuals to be more
  responsive to control than relevant questions.
  The second requires guilty persons to respond
  more intensely to relevant than control
  questions. The plausibility of both of these
  assumptions can be easily challenged.
• The notion that guilty suspects will necessarily
  respond more strongly to relevant than control
  questions is unlikely for several reasons.
• The notion that a guilty suspects will
  necessarily respond more strongly to relevant
  than control questions is unlikely for several
  reasons.
• If a guilty person passed the test, there would
  be no confession to guilt and that the test was
  wrong? So how accurate are the studies dont for
  lie detection?
• How can lie detection be verified as accurately
  recording the truth or not?
• Brain fingerprinting Is this an accurate method
  when people have memory problems? What if
  someone is telling the truth but is factually
  wrong?
• There is not a 100 accurate way lie detection
  method

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Legal Issues

• Frye vs. United States The Frye standard is a
  legal precedent regarding the admissibility of
  scientific examinations or experiments in legal
  precedings. To meet the Frye standard, scientific
  evidence presented to the court must be
  interpreted by the court as "generally accepted"
  by a meaningful segment of the associated
  scientific community.
• Daubert v. Merrell Dow Pharmaceuticals (1993)
  The Daubert standard is a legal precedent
  regarding the admissibility of expert witnesses
  testimony during legal proceedings.
• United States v. Scheffer (1998) Military Rule
  of Evidence 707 (failure to take, or taking a
  polygraph examination shall not be admitted into
  evidence) v. 6th Amendment (right to defend
  oneself)
• After United States v. Scheffer, most
  jurisdictions exclude all polygraphic evidence.
  However, two federal circuits held that
  polygraphic tests could be admitted on a
  case-by-case basis and New Mexico admitted
  polygraphic evidence.
• The Employee Polygraph Protection Act of 1988
• Established guidelines for polygraph testing and
  imposed restrictions on private employers such as
  companies and corporations
• Does NOT affect public employers such as police
  agencies or other governmental institutions.
• Should public employers be trusted more than
  private employers?

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Legal Issues cont.

• Iowa v. Harrington
• a post-conviction relief action undertaken 26
  years after a murder EEG responses to probes
  such as across street, parked cars, and
  weeds and grass, all of which related to the
  crime scene, showed that he had no memory of the
  crime the district judge ultimately did not find
  the evidence persuasive
• By allowing scientific testimony regarding
  truthfulness into evidence, is the court invading
  the purview of the jury?
• Can you test defendants? Can you test
  nondefendant witnesses?
• Bias detection can we test a jury to see if they
  will be biased?
• Should lie detection methods be used in courts?

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Can you beat a lie detector?

• There are three basic types of questions you will
  be asked relevant, irrelevant, and control.
• Dont admit anything relevant.
• Say only what you need to. Yes or No answers
• Maintain a normal breathing rate of 15-30 breaths
  per minute but alter it during control questions.
• Bite your tongue. Bite the side of your tongue
  hard enough to cause pain.
• Insert a small nail or tack in the toe area of
  your shoe and press down on this during the
  control questions to elicit a pain response.
• Contract your anal sphincter muscle when a
  control question is asked (pressure-sensitive
  seat pads).
• Your first impulse will be to try to conceal all
  emotion, but that is exactly what not to do. The
  physical effort required to conceal emotion shows
  up and could often be detected without a machine.
  So, in beating the lie detector, intensify them
  as much as possible.
• To confuse the test from the start, you might
  tense your muscles when the rubber is wrapped
  around your arm.
• The way to beat the association test is simply to
  blurt out the first word you think of in
  association. The body was found in a park, so
  when one of the key words given you is "park,"
  naturally the first word you think of, whether
  you're guilty or innocent, is "murder."
• Seeing that you appear to be not afraid of his
  machine, the operator will be naive enough to
  think you innocent.

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How to tell when someone is lying

• General Verbal Responses
• May take longer to start answering
• May answer to quickly or before the question is
  completed
• Often ask the questioner to repeat the question
  or they repeat it themselves
• Overly polite or apologetic dialog
• Persistent complaints
• Unnatural silence
• The Behavioral Clusters of Deception
• Deceptive people follow certain behavioral
  patterns.
• - Macro Patterns -
• General Behaviors
• Increased discomfort and anxiety, hostility,
  unmerited anger towards you, persistent
  evasiveness, resistance
• Posture
• Early signs of extreme rigidity followed by
  alternating stiffness and relaxation. Hands,
  legs, objects put in front of body to form a
  barrier (folding arms, crossing legs, etc.).
  Feigned lack of interest. Posture changes caused
  by topic changes. Not facing you. Distancing or
  leaning away from you.
• Gestures and Movements
• Rubbing the forehead near the temple region.
  Squeezing the face, rubbing the neck, or stroking
  the back of the head with the hand. Using fewer
  hand movements to illustrate their actions than
  usual. Movement away from you. Lip licking and
  hard swallowing. Wringing hands. Hiding the eyes
• - Micro Patterns -expressed on the face
• General Expressions
• Averting the eyes. Focusing the eyes - some will
  try to stare down to show control. (A truthful
  person stares only half the time on average).
  Face whitening.Face flushing.

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Eye Movement
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How to lie

• The first thing you do when lying is to tell the
  truth -- not the whole truth, but just enough to
  make the lie itself seem true. If you sense that
  someone else suspects you of lying, admit to
  something small or untrue. Think of some specific
  true thing (place, person, event, story) that
  your lie will fit into and use those details if
  you are questioned. This gives you a bank of
  specific details to draw on so you don't have to
  keep making things up as you go along.
• The trick is convincing your sub-conscious mind
  that you're telling the truth. An example of this
  may be, "Did I wreck the car? Well, I drove it
  into a wall. So, the wall wrecked the car. I just
  moved it!
• Look the person you are lying to in the eye.
  Don't look around. Try making your eyes go big
  and letting your mouth hang open a little for an
  innocent/shocked look.
• Never forget about your lie, and treat it like it
  actually happened. Mention it in conversations
  the way you would if it was true. Silence about a
  certain subject can arouse suspicion, especially
  in retrospect.
• Use named, recognizable people.

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But most importantly Always tell the truth!
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Youre Detective Poly.

• 1. Start with invasive CONTROL questions to begin
  to recognize his/her regular behavior.
• YOU What class do you have tomorrow?
• YOU Who is your favorite musician? Whats the
  favorite concert you have ever been too?
• YOU What restaurants do you recommend? What kind
  of food do they serve?
• 2. Now lets get to the truth!! Here are some
  suggested ?sFeel free to ask different ones, but
  the key is to probe.
• YOU Have you ever lied to your best friend? What
  did you say to them?
• YOU Since youve been at Vanderbilt have you
  washed your bed sheets?
• YOU Where were you born? What was the name of
  the hospital?
• YOU In the past month, have you deliberately not
  answered someones phone call? Who was the
  person?
• 3. DID HE/SHE PASS?

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Youre Suspect Suspicion

1. You will be asked a set of control questions
   first that you must answer truthfully for the
   experiment
2. Let the lying begin! (Note You may answer all of
   the questions right or all wrong if you want.
   This might throw Detective Poly off.)
3. Evaluation from Detective Poly