copyright © 2012 pearson canada inc.4 - 1 chapter 4 deception

Copyright © 2012 Pearson Canada Inc. 4 - 1

Chapter 4

Deception


Learning Objectives

• Describe the two types of polygraph tests

• Describe the most common errors made by the Comparison Question Test (CQT) and Concealed Information Test (CIT)

• Describe physiologically based alternatives to the polygraph

• Outline the verbal and non-verbal cues of deception


Learning Objectives

• Define malingering, and list the three explanatory models of malingering

• Differentiate between the types of studies used to examine malingering


Polygraph Method

• Based on the belief that deception is related to physiological change

• Measures:

– Respiration

– Heart rate

– Sweating


Uses of Polygraph

• Helps in criminal investigations (suspect is asked to take a polygraph test)

• Verify a crime has occurred (victim is asked to take a polygraph test)

• Monitoring sexual offenders on probation (United States)

• Pre-employment screening for security agencies and police


Types of Polygraph Tests

• There are two main types of polygraph tests:

– Comparison Question Test (CQT)

– Concealed Information Test (CIT)


Comparison Question Test

• Includes three types of questions:– Irrelevant– Relevant– Comparison

• Deception is assessed by comparing physiological responses between relevant and comparison questions


Comparison Question Test: Sample Questions

Question Purpose Example

Irrelevant Used to obtain a baseline.

Are you left handed?

Relevant Deal with the crime.

Did you assault Sam Smith on March 11th?

Comparison Deal with prior antisocial behaviour.

Before age 25, did you ever verbally threaten to hurt anyone?


Phases of the CQT

• Pre-test interview: Interview with suspect to develop the comparison questions

• Polygraph exam: Questions are asked while suspect’s physiological responses are measured

• Scoring: Polygraph examiner scores the physiological responses to determine if the suspect is truthful, deceptive, or inconclusive

• Post-test interview: If a suspect is judged deceptive they are pressured to confess


Control 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


Concealed Information Test

• Assesses if suspect has information that only the criminal would know

• Asks suspects multiple-choice questions, one option is correct

• Assumes if the suspect is guilty they will react strongly to correct information

• Rarely used in Canada or United States


Types of Polygraph Studies

• Laboratory studies

– Ground truth is known

– Limited application to real-life situations

• Field studies

– Real-life situations and actual suspects

– Ground truth is not known


Accuracy of the CQT

• Majority of guilty suspects correctly identified– 84% to 92% guilty correctly identified

• Relatively large number of innocent suspects falsely identified as guilty– 9% to 24% false positive errors

• Accuracy of original examiners higher than blind scorers


Accuracy of CIT

• No field studies have been conducted in North America

• Very accurate at identifying innocent participants

– Around 95% correctly identified

• Less accurate at identifying guilty participants

– Around 85% correctly identified


Countermeasures

• Both physical and mental countermeasures dramatically reduce the effectiveness of the CQT (Honts et al., 1994)

• The CIT does not appear to be effected by anti-anxiety drugs (Iacono et al., 1992)


Admissibility of Polygraph

• Did not pass general acceptance test when first admitted as evidence in court (Frye v. United States, 1923)

• Currently allowed in some States if agreed by both prosecution and defence

• Not admissible into evidence in Canadian courts (R. v. Beland, 1987)


Other Measures

• Thermal imaging:

– Detects facial warming due to blood flow

• Event-related brain potentials (ERP)

– Electrodes measure brain activity in

response to a significant stimulus

– P300 used to detect guilty knowledge


Other Measures: fMRI

• Functional magnetic resonance imaging (fMRI)

– Measures differences in brain activity when people are being honest versus deceptive

– Different parts of the brain are activated when person is deceptive versus when they are telling the truth


Detecting Deception:Verbal Cues

• Verbal cues most consistently related to deception include:

– Higher voice pitch

– Increased speech disturbance (ah, umm)

– Slower speech

• Pattern of verbal cues may depend on how cognitively complex the lie is


Verbal Characteristics of Deception (Table 4.3)

• Speech fillers

– Frequency of saying “ah” or “umm”

• Speech errors– Repetition, change, slips of tongue

• Pitch of voice• Rate of speech• Speech pauses


Non-verbal Characteristics of Deception (Table 4.3)

• Gaze aversion

• Smiling

• Blinking

• Fidgeting

• Illustrators

• Hand or finger movements

• Leg or foot movements

• Body movements

• Shrugs

• Head movements

• Shifting positions


Detecting Deception:Verbal Cues

• Verbal cues that are indicative of honesty:– Make corrections in account– Admit to lack of memory

• Verbal cues that are indicative of deception:– Little detail – Less compelling accounts– More nervous and tense


Detecting Deception: Professionals

• Vrij (2000) reported accuracy rates:

– Truths = 67%

– Lies = 44%

• Accuracy of professional lie catchers vary:

– Have a truthfulness bias

– Tend to rely on wrong cues


Factitious Disorder

• Intentionally produced physical or psychological symptoms

• Internal motivation to assume the sick role

• Absence of external incentives


Somatoform Disorder

• Physical symptoms that cannot be explained by organic impairment

• Symptoms are not intentionally produced

• Often co-occurs with depression or anxiety


Malingering

• Psychological or physical symptoms are voluntary

• There are external motivations for the production of symptoms– Malinger mental illness to avoid

criminal punishment, to obtain drugs, or for compensation such as disability

– Prevalence quite high in forensic settings


Defensiveness

• Defensiveness refers to the conscious denial or minimization of physical or psychological symptoms

– Might wish to appear high functioning to be seen as a fit parent

– Some patients may not want to admit they certain symptoms

Copyright © 2012 Pearson Canada Inc. 27


Explanations of Malingering

• Three explanatory models of malingering (Rogers, 1990):

– Pathogenic model

– Criminological model

– Adaptational model


Pathogenic Model

• Assumes malingering results from an underlying mental disorder

• The patient attempts to gain control over his or her pathology by creating fictitious symptoms

• Little empirical support


Criminological Model

• Malingering due to: – Antisocial personality disorder (APD)– Forensic assessment– Lack of cooperation– Discrepancy between findings

• Research does not support an association between APD or cooperation and malingering


Adaptational Model

• Asserts malingering is likely to occur when:– A perceived adversarial context is

present– Personal stakes are very high– No other viable alternatives are

perceived• Research findings support this model


Research Assessing Malingering

• Three basic designs:

– Case study

– Simulation

– Known groups


Case Studies

• Useful for generating a wide variety of hypotheses

• Only way to study rare syndromes


Simulation Design

• Most frequently used

• Participants are told to malinger a specific disorder and compared to

– Control group

– Clinical comparison group

• High experimental rigour

• Limited generalizability to the real world


Known-Groups Design

• Involves two stages:

– Establishing the criterion groups (e.g. genuine patients and malingers)

– Analysis of the similarities and differences between criterion groups

• Good generalizability to real-world settings

• Problems classifying criterion groups


Detecting Malingered Psychosis

• Clues regarding the symptoms:– Report rare, atypical symptoms, or

absurd symptoms – Report atypical delusions or

hallucinations– Absence of subtle symptoms – Continuous hallucinations rather than

intermittent

(continued)


Detecting Malingered Psychosis (continued)

• Other clues:

– Accuse clinician of not believing them

– Presence of accomplice

– Crime fits pattern of criminal history


Assessments: SIRS

• The Structured Interview of Reported Symptoms (SIRS; Rogers et al., 1992)

– Uses a structured interview

– 172 items organized into 8 scales

– Research indicates good validity


Assessments: M-FAST

• The M-FAST test (Miller, 2000)

– Interview-based method

– 25 items organized into 9 scales

– Useful and reliable screening test for malingering


Assessments: MMPI/MMPI-2

• MMPI/MMPI-2 are self-report personality inventories – They contain scales such as the

infrequency (F) scale and the Back F (FB) scale selected to detect unusual or atypical symptoms

– Research indicates these scales are the most useful at detecting malingerers (Rogers et al., 2003)

copyright © 2012 pearson canada inc.4 - 1 chapter 4 deception

Documents

pearson canada

types of questions

malingering slide

behaviour slide

relevant questions

police slide

polygraph examiner

polygraph method