LS272 Chapter Notes - Chapter 4: Ground Truth, Polygraph, Autonomic Nervous System
Chapter IV: Deception
Polygraph Technique
• deception is associated with physiological change
• polygraph: device for recording an ind’s autonomic nervous system responses
• applications: help in criminal investigations, assess and monitor sexual offenders on probation
• polygraph disclosure tests: polygraph tests used to uncover info. about an offender’s past behaviour
Types of Polygraph Tests
• comparison question test/control question test:
• includes irrelevant questions unrelated to the crime, relevant questions concerning crime, and
comparison questions concerning person’s honesty and past history prior to event
• most commonly used
• critical component of interview is the pretest interview to develop comparison questions
• innocent = react more to comparison questions, guilty = react more to relevant questions
• has three possible outcomes: truthful, deceptive, inconclusive
• concealed information test:
• designed to determine if the person knows details about a crime
• series of questions in a multiple-choice format
Validity of Polygraph Tests
• types of studies: validity classified into either laboratory and field studies
• laboratory: main advantage is experimenter knows ground truth (knowledge of whether the
person is actually guilty/innocent)
• disadvantage: large motivational and emotional diffs. b/w volunteers and actual suspects
• field studies: involve real life situations and actual criminal suspects
• largest problem = establishing ground truth
• polygraph tests, accurate or not?
• CQT studies: premise underlying doesn’t apply to all suspects, innocent respond more to
relevant than comparison questions
• assessments of CIT based on lab and field studies
• great at identifying innocents, but not with guilty people
• vulnerable to false-negative errors (falsely classifying guilty as innocents)
Can the Guilty Learn to Beat the Polygraph?
• countermeasures: techniques used to try to conceal guilt
• physical: biting tongue, pressing toes on floor
• mental: counting backward by 7 from a number greater than 100
• worked, 50% beating guilty suspects
• anti-anxiety drugs: not worked, no effect
Admissibility of Polygraph Evidence
• polygraph results first submitted as evidence in court in Frye v. United States
• denied to have the results admitted as evidence
• requirement = must obtain general acceptance by relevant scientific community
• not admissible in Canadian criminal courts as well as U.S. courts
Brain-Based Deception Research
find more resources at oneclass.com
find more resources at oneclass.com
Document Summary
Some people better at detecting deception: the ability to distinguish lies from truth tends to be only slightly better than chance. It is possible to improve judgement accuracy through training. Assessment of malingering and deception disorders of deception: deception is a central component of some psychological disorders. The disorders described vary on two dimensions: 1. Whether the person intentionally or consciously produces the symptoms: 2. Whether the motivation is internal or external: somatic symptoms and related disorders, one of these disorders is factitious disorder in which the person"s physical and psychological symptoms are intentionally produced and are adopted for no external rewards. Includes falsification of physical or psychological signs or symptoms or induction of injury or disease . Presents themself as ill to others while being aware they are intentionally producing the symptoms: munchausen syndrome by proxy is called factitious disorder imposed on another to describe cases in which parents falsified symptoms within their children.