Lecture 3 part 2 Flashcards
Stages of deception detection process
- Appropriate attention must be given to relevant cues
- Relevant cues may be interpreted as a sign of deceit
- Errors can occur at each stage (Othello error, Brokhaw hazard)
Othello error
- Truthful but appears to be lying
- looks anxious or nervous
Brokhaw hazard
- Idiosyncrasies misinterpreted as deceit
- Something seems off about the person
Polygraph technique
- Based on belief that deception is related to physiological change
- Breathing, heart rate, blood pressure, sweating
- Helps in criminal investigation
- Verify a crime has occurred
- Monitoring sexual offenders on probation
- Pre-employment screening for security agencies and police
Types polygraph tests
- Comparison question test (CQT)
- Concealed information test (CIT) (aka guilty information test)
Comparison question test (CQT)
- Irrelevant questions
- Relevant questions
- Comparison
- Compares physiological responses between relevant and comparison questions
Phases of comparison question test (CQT)
- Pre-test interview
- Polygraph exam
- Scoring
- Post-test interview
Comparison question test assumptions
- Assumes guilty people react more to relevant questions and innocent people react more to comparison questions
- Suspect falsely accused of a crime might react more strongly to questions about the crime than to vague questions concerning past behaviour
- Guilty suspects may not react as strongly to relevant questions if they have been repeatedly exposed to those questions
Concealed Knowledge test
- Assumes suspect has information that only the criminal would know
- Asks multiple choice questions
- Assumes if suspect guilty they will react strongly to correct answers
- Rarely used in Canada and USA
Validity of polygraph studies
- Laboratory studies (ground truth known, limited application to real-life situations)
- Field studies (real-life situations and actual suspects, ground truths not known)
Accuracy of comparison question test
- Majority of suspects correctly identified
- ~90% guilty correctly identified
- ~15% not guilty falsely identified
Accuracy of concealed knowledge test
- Very accurate
- 95% correctly identify innocent
- ~80% correctly identify guilty
Countermeasures of polygraph test
- Both physical and psychological can dramatically reduce effectiveness
- Some drugs can have an impact
- Personality
Admissibility of polygraph
- Did not pass general acceptance test when first admitted as evidence in court
- Not admissible into evidence in Canadian courts
Brain-based deception research
- Event-related brain potentials (ERP), electrodes measure brain activity in response to significant stimulus (>P300)
- Functional magnetic resonance imaging (FMRI), measures differences in brain activity between honest and deceptive
Verbal cues for detecting deception
- Higher voice pitch
- Increased speech disturbance
- Slower speech
- Pattern on verbal clues may depend on cognitive complexity of lie
Verbal cues that indicate being honest
- Make corrections in account
- Admit to lack of memory
Verbal cues that indicate being deceptive
- Little detail
- Less compelling accounts
- More nervous and tense
Malingering
- Psychological or physical symptoms are voluntary
- External motivations for production of symptoms (mental illness to avoid criminal punishment or for drugs)
Defensiveness
- Refers to conscious denial or minimization of physical or psychological symptoms
- Might want to appear high functioning
- May not want to admit certain things
Explanations of malingering
- Pathogenic model
- Criminological model
- Adaptational model
Pathogenic model
- Assumes malingering results from underlying mental disorder
- Patient attempts to gain control over their pathology by creating fictitious symptoms
- Little empirical support
Criminological model
- Malingering in forensic assessments suspected due to antisocial personality disorder (APD), lack of cooperation during assessment, or discrepancy between self and others reports
- Research does not support association between APD or cooperation and malingering
Adaptional model
- Asserts malingering is likely to occur when a perceived adversarial context is present, personal stakes are high, or no other viable alternatives are perceived
- Research findings support this model
How to study malingering
- Case studies
- Simulation
- Known groups
Case studies to study malingering
- Useful for generating wide variety of hypotheses
- Only way to study rare syndromes
Simulations to study malingering
- Most frequently used
- Participants told to malinger specific disorder and compared to control group and clinical comparison group
- High experimental rigour
- Limited generalizability to real world
Known-groups design to study malingering
- Involves establishing criterion groups and analysis of similarities and differences between criterion group
- Good generalizability to real-world settings
- Problems classifying criterion groups
Detecting malingered psychosis
Clues regarding symptoms:
- Report rare, atypical symptoms
- Report atypical delusions or hallucinations
- Absence of subtle symptoms
- continuous hallucinations rather than intermittent
SIRS assessments for malingered psychosis
- Structured Interview of Reported Symptoms
- Uses structured interview
- 172 items organized into 8 scale
- Research indicates good validity
MMPI assessments for malingered psychosis
- Self-reported personality inventories
- Contains scales such as infrequency (F) scale and back F (Fb) scale selected to detect unusual or atypical symptoms
- Research indicates these scales are the most useful at detecting malingerers
