Polygraph prelim

• Polygraphy


  The scientific method of detecting deception with the use of a polygraph instrument. This is the new name of LIE DETECTION.
• Polygraph


  A recorder of psycho-physiological changes occurring within the examinee's body as the polygraph examiner asks a series of test questions. It is a combination of medical devices used to monitor the physical conditions of patients.
• Lie Detector


  The popular but misleading name of the Polygraph. It makes various ink recordings of a person's body functions which will be interpreted by the polygraphist to determine whether the subject has been lying or not.
• Truth Verifier


  Another name for the Polygraph, since statistics show that the vast majority of the instances the instrument verifies an innocent person's truthfulness.
• Concepts of Polygraph Examination


  • Used to test an individual for the purpose of detecting deception or verifying the truthfulness of his statements
  • It is done by recording identifiable physiological reactions of the subject, such as blood pressure, pulse rate, respiration and skin resistance
  • The effectiveness of the polygraph in recording symptoms of deceptions is based on the theory that a conscious mental effort on the part of a normal person to deceive causes involuntary physiological changes that are in effect a body's reaction to an imminent danger to its well being
• Objectives of a Polygraph Examination


  • Obtain additional investigation leads to the facts of the case/offenses
  • Ascertain if a person is telling the truth
  • Locate the fruits or tools of the crime and whereabouts of wanted persons
  • Identify other persons involved (accomplices of crime)
  • Obtain valuable information from reluctant witnesses
  • Eliminate the innocent suspects
• Principal uses of the Polygraph Examination


  • Aid in investigating criminal incidents and issues
  • Speeds up the process of investigation
  • Eliminates innocent suspects
  • Pre-employment screening
  • Honesty test (Periodic test)
• Lie


  An untruthful statement, falsehood, anything that deceives or creates false impression, untrue statements especially with intent to deceive or to give an erroneous or misleading impression. It is also synonymous to deceit, deception, fabrication, falsehood and untruth.
• Detection


  The act of detecting, discovery, perceiving, finding, or uncovering something obscure such as a lie.
• General Kinds of Lie

  • White Lie or Benign Lie - Used to protect or maintain the harmony of friendship or any relationship
  • Pathological Lie - Made by persons who cannot distinguish right from wrong
  • Red Lie - Involves political interests and motives, part of communist propaganda strategy
  • Black Lie - Accompanies pretensions and hypocrisies, intriguing to cause dishonor or discredit ones good image
  • Malicious or Judicial Lie - Very pure and unjustifiable kind of lie that is intended purely to mislead or obstruct justice
• Fabrication

  • Fabrication A lie told when someone submits a statement as truth, without knowing for certain whether or not it actually is trueen someone submits a statement as truth, without knowing for certain whether or not it actually is true
  • Contextual lies - Stating part of the truth out of context, knowing that without complete information, it gives a false
• Types of Liars


  • Panic Liars - Lie to avoid the consequences of a confession, afraid of embarrassment
  • Occupational Liars - Lie when it has a higher "pay off than telling the truth
  • Tournament Liars - Love to lie and are excited by the challenge of not being detected
  • Psychopathic Liars - Have no conscience and show no regret for dishonesty and no manifestation of guilt
  • Ethnological Liars - Taught not to be a "squealer" (reveal secrets of their organization)
  • Pathological Liars - Cannot distinguish right from wrong due to their sick mind
  • Black Liars - Always pretend what they are and what they think of themselves
• There is no instrument that could detect lies. The popular name, "Lie Detector," given to a polygraph, is somewhat misleading.
• Early Methods of Detecting Deception

  • Red Hot Iron Ordeal - Practiced on the hill tribe of Rajhmal in the North Bengal
  • Ordeal by the Balance - An ordeal practiced in the Vishnu, India
  • Boiling Water Ordeal - Common in Africa
  • Ordeal By Rice Chewing - An ordeal practiced by the Indians
  • Ordeal of the Red Water - Used in a wide region of Eastern Africa
  • Combination of Drinks and Food Ordeal - An ordeal practiced by the West African region
  • Trial by Combat - A fight between the accuser and the accused, originated in India
  • Trial by Torture - The accused was put into a severe physical test
  • Drinking Ordeal - The accused was given a decoction to drink by a priest
  • Trial of the Eucharist - This trial is reserved for the clergy, and administered with pomp and ceremony
• Popular Countries that Practiced Trial by Ordeal

  • Burma
  • Borneo
  • Greece
  • Nigeria
  • Europe and Early United States (17th Century)
• Trial by Water (Europe and Early United States)


  1. Accused was bound (hand and foot) and then cast into the body of water

  2. If the accused sank, he was hauled to the surface half-drowned and deemed innocent

  3. If he floated, he was deemed guilty and burned to death
• Observable Clues of lying


  Body postures and facial expressions that can be used as hints to determine whether someone is lying or telling the truth
• Hypnotism


  1. Subject is set up and instructed to sit quietly and gaze at flashing light or shiny object

  2. Used to detect deception but not admissible in court due to lack of scientific acceptance, possibility of fabrication, and subjectivity of the examiner
• Word Association Test


  1. Subject is given a list of stimulus words or objects and instructed to respond with the first word that comes to mind

  2. Used to observe how thinking reactions are linked to emotional habits
• Truth Serum Method


  1. Drug called Byosine Hydrobromide is administered to the subject to induce a state of delirium

  2. Subject is then questioned and expected to disclose everything truthfully

  3. Not admissible as evidence in court but useful for criminal investigation
• Narco-analysis or Narco-synthesis


  1. Drug Sodium Amytal or Sodium Pentothal is administered to the subject

  2. When the effects appear, questioning starts to obtain free speech from the subject

  3. Not admissible in court
• Intoxication


  1. Subject is allowed to take alcoholic beverages up to the point of intoxication

  2. Interrogation is done during the excitatory effect of alcohol

  3. Confession made while intoxicated is admissible if the subject can recollect the facts after the influence of alcohol has disappeared
• Psychological Stress Evaluator (PSE)


  1. Detects, measures, and graphically displays the voice modulations that are suppressed when a person is under stress, as when lying

  2. When a person is relaxed and responding honestly, the inaudible frequencies are registered clearly on the instrument
• Police Methods of Detecting Deception


  • Information gathering through record check, surveillance and intelligence check
  • Investigation and/or interview to obtain admission or confession
  • Instrumentation through interrogation or criminalistic processes with the use of different investigative forensic sciences
• During the 19th century, Dr. Hans Gross, an Austrian known as the "Father of Criminalistics", defined search for truth as the basis and goal of all criminal investigation
• Five Wives and One Husband

  WHAT, WHEN, WHERE, WHO, WHY and HOW
• Three Eyes (3 I's) of investigation

  • Information gathering
  • Investigation and/or interview to obtain admission/confession
  • Instrumentation through interrogation or criminalistic processes
• Criminalist's work


  Battle against lies, discover the truth
• DANIEL DEFOE - Suggested taking the pulse of a suspicious fellow as a method for distinguishing truthfulness from lying


  1730
• External Friction


  Electricity generated by the body, sweat glands store and discharge electricity
• Synthetic polymers


  • nylon
  • polyethylene
  • polyester
  • Teflon
  • epoxy
• Plethysmograph

  Instrument used by ANGELO MOSSO to study blood circulation and breathing patterns in response to stimuli
• Electro-dermal response


  Caused by an increase in the action of the heart and vital energy converted with human emotions
• Cardiograph

  Instrument constructed by SIR JAMES MACKENZIE to record undulated line tracings of the vascular pulses
• Hydrosphygmograph

  Modified by CESARE LOMBROSO to measure physiological changes in crime suspects during interrogation
• Galvanograph

  Suggested by GEORGE STICKER for detecting deception, influenced by exciting mental impressions
• Psychogalvanic Reflex


  Idea by OTTO VERAGUTH that the electrical phenomenon was due to the activity of the sweat glands
• Pneumograph

  Instrument used by VITTORIO BENUSSI to graphically measure an examinee's inhalation and exhalation, demonstrating changes in breathing patterns accompany deception
• Sphygmomanometer


  Used by WILLIAM MOULTON MARSTON to measure systolic blood pressure during interrogation
• Larson Polygraph


  Instrument developed by JOHN A. LARSON to continuously record blood pressure, pulse, and respiration