Week 9 - Malingering, Deception, Psychopathy Flashcards
Polygraph uses in Canada
- To pressure a suspect to confess
- Alleged victims of crimes to verify if they are being truthful
- Used by insurance companies to verify a claim
- Used as screening for selection tests (RCMP)
The Comparison Question Test
- Most used test
- Yes or no questions, no elaboration
- The fist few questions are irrelevant to the crime – used to establish a baseline
- Relevant questions
- Comparison questions/control questions
- a person who knows stuff about the crime would react more to relevant questions than control question
The Concealed Information Test
Does the person know details about the crime that only the culprit would know?
- Asked a series of questions: real info and distractors (Did you kill the victim with a a) gun b) rifle c) knife d) crowbar)
- Which had the biggest reaction?
Concealed Information Test problems
- No details of the crime can be known by the public
- Limited number of questions they can ask
- More costly and difficult to put together
Polygraph accuracy
Comparison
- Most guilty suspects are correctly identified as guilty – more accurate than with identifying innocent people
- High number of false positives
Concealed Info
- Effective at identifying innocent participants but not so much for guilty ones
- High number of false negatives
Are polygraph test results admissible in court?
- Frye v. United States (1923): evidence rejected as it failed to meet a “general acceptance” by scienticts
- R. v. Beland (1987), the Supreme Court of Canada ruled that polygraph may cause jurors to weigh polygraph evidence more than it deserves when determining the verdict.
- Still used by law enforcement as an investigative tool
How to beat polygraph
increase arousal for control questions
- Physical countermeasures: pressing toes into floor, biting tongue
- Mental countermeasures: counting backwards for seven
Other Deception Detection Techniques
- Event-related brain potentials
- Verbal cues
- Non-verbal cues
- Hypnosis
Detecting deception - professional v. layperson
- people rely on behaviours that lack predictive validity (i.e., cues such as gaze aversion and fidgeting)
- most people have a truth-bias – which is the tendency of people to judge more messages as truthful than deceptive
- there are only small differences between liars and truth-tellers
many professionals who encounter deception within their profession are not very accurate at detecting deception, but better in high-stakes situations
Secret Service & deception detection
Secret Service agents perform better
- Accuracy was higher for participants who used multiple cues in their credibility judgments.
- It may be possible to increase accuracy through training
- Professionals are better at identifying truths than deception
Factitious disorder
A disorder in which the person’s physical and psychological symptoms are intentionally produced and are adopted to assume the role of a sick person
- There is an absence of external incentives
- Might be aware that they are intentional providing symptoms, but they don’t know the psychological reason why
- Munchausen syndrome – physical complaint
Somatoform disorder
A disorder in which physical symptoms suggest a physical illness but have no known underlying physiological cause and the symptoms are not intentionally produced
- Belief that they are sick
- The doctors don’t know what is wrong
- Eventually doctors will find that the symptoms are probably due to anxiety/stress (metal disorder)
Malingering
Intentionally faking psychological or physical symptoms for some type of external gain
- The psychological or physical symptoms are clearly under voluntary control
- There are external motivations for the production of symptoms (e.g., be declared unfit for trial)
Three explanatory models of malingering (Rogers, 1990)
- Pathogenic (pathologic) model
- Underlying mental disorder; exaggerates symptoms or creates symptoms to obtain control
- Criminological model
- Antisocial personality disorder; forensic assessment; lack of cooperation; marked discrepancy between subjective complains and objective findings
- Adaptational model
- Presence of a perceived adversarial context; personal stakes are very high, no other alternative are perceived
Cues to malingering psychosis
- Understandable motive for committing crime
- Presence of a partner in the crime
- Current crime fits pattern of previous criminal history
- Suspicious hallucinations
- Suspicious delusions
- Marked discrepancies in interview versus non interview behaviour
- Sudden emergence of psychotic symptoms to explain criminal act
- Absence of any subtle signs of psychosis
