Polygraph Techniques: CQT and CIT

Polygraph Techniques

• Polygraph techniques operate on the principle that deception correlates with psychological changes, measuring respiration, heart rate, and sweating.
• Polygraphs aid criminal investigations, verify crimes, monitor sexual offenders on probation, and pre-employment screening.

Types of Polygraph Tests

• Comparison Question Test (CQT) and Concealed Information Test (CIT) are two main types of polygraph tests.

Comparison Question Test (CQT)

• CQT includes irrelevant, relevant, and comparison questions.
• Deception is determined by comparing psychological responses to different question types.
• During the pre-test interview, the suspect is interviewed to develop comparison questions.
• The polygraph exam involves asking questions while measuring physiological responses.
• After the exam, the results are scored, and a post-test interview may occur.

Control Question Test

• Control Question test assumes guilty people react more to relevant questions, while innocent people react more to comparison questions.
• Suspects falsely accused may react strongly to crime-related questions.
• Guilty suspects' reactions to relevant questions may diminish with repeated exposure.

Concealed Information Test (CIT)

• The CIT assesses whether a suspect has knowledge only the criminal would possess.
• Suspects are asked multiple-choice questions with one correct option.
• It is assumed that guilty suspects will react strongly to correct information.
• The CIT is more commonly used in Europe and rarely used in Canada.

Validity of Polygraph

• Laboratory studies offer known ground truth but limited real-world applicability.
• Field studies involve real-life situations but lack known ground truth.

Accuracy of the CQT

• The majority of guilty suspects are correctly identified (84% to 92%).
• A relatively large number of innocent suspects are falsely identified as guilty (9% to 24% false positive errors).

Accuracy of CIT

• No field studies have been conducted in North America on CIT accuracy.
• CIT is very accurate at identifying innocent participants.

Countermeasures

• Physical and mental countermeasures can significantly reduce CQT effectiveness; 50% of guilty suspects can beat the polygraph.

Admissibility of Polygraph

• Polygraph evidence did not pass the general acceptance test and is not admissible in Canadian courts.

Brain-Based Deception Research

• Event-related brain potentials (ERPs) measure brain activity in response to stimuli.
• P300 responses to infrequent, significant stimuli are stronger in guilty suspects for crime-relevant questions.
• Functional magnetic resonance imaging (fMRI) measures differences in brain activity during honesty versus deception, activating different brain regions.

Verbal Cues to Deception

• Consistent verbal cues to deception include a higher voice pitch, increased speech disturbances such as "ahh" and "ummm," and slower speech.
• The pattern of verbal cues depends on the cognitive complexity of the lie.

Verbal Cues when Honest

• Making corrections in account
• Admitting to lack of memory

Detecting Deception: Professionals

• Lie detection rates among professionals and lay people may not differ under some conditions.
• Professionals tend to detect high-stakes lies better than low-stakes lies.

Disorders of Deception

• In factitious disorder, individuals intentionally produce physical or psychological symptoms with an internal motivation to assume the sick role, without gaining anything tangible.
• Malingering involves voluntary psychological or physical symptoms for external motivations such as avoiding punishment or obtaining drugs or compensation.
• Defensiveness refers to the conscious denial or minimization of physical or psychological symptoms.

Eyewitness Testimonies

• Eyewitness testimony relies on encoding, storing, and retrieving information.
• Storing memories requires attention, encoding, short-term memory, and long-term memory, with potential problems at each stage.

Stages of Memory

• The stages of memory include:
  • Perception/attention stage: Sensory input is received and noticed.
  • Encoding stage: Information is converted into a usable form.
  • Short-term memory: Temporary storage of information.
  • Long-term memory: Storing information for later retrieval.
  • Retrieval stage: Accessing stored information for recall.

Perception

• Sensory input is transformed and organized meaningfully by processors in the cerebral cortex through interpretive and non-conscious processes.
• The end product is selective and incomplete, and sensory defects may be present in some individuals.

Types of Eyewitness Memory

• Recall memory involves reporting details of a previously witnessed event or person.
• Recognition memory involves determining whether what is currently being viewed or heard is the same as the previously witnessed item or person.

Studying Eyewitness Issues

• Eyewitness issues can be studied using archival data (police reports, transcriptions), naturalistic observation, and laboratory simulation.

Types of Eyewitness Independent Variables

• Estimator variables, such as the age of a witness, are present at the time of the crime and cannot be changed.
• System variables can be manipulated to increase or decrease eyewitness accuracy, such as lineup procedures.

Types of Eyewitness Dependent Variables

• Common dependent variables in eyewitness studies include:
  • Recall of the event;
  • Recall of the perpetrator;
  • Recognition of the culprit.

Recall of the Event/Perpetrator

• Recall of the crime takes two forms:
  • Open-ended recall/free narrative, where witnesses recount what they witnessed without prompting.
  • Direct question recall, where witnesses are asked specific questions about the event/perpetrator.

Recognition of the Perpetrator

• Recognition of the perpetrator is usually done through a lineup.

Questioning Witnesses (Gathering Information)

• Lack of training, interview content, and failure to recognize the dynamics of the interview can affect the quality of information gathered.

Lack of Training

• Police traditionally receive little training in interviewing witnesses.
• Training manuals often do not cover effective interviewing techniques.

Interview Content

• Police interviews often involve asking witnesses to describe what happened, asking brief, direct questions, and providing little assistance to enhance recollection.
• The goal of the interview is to obtain a complete and accurate report of the event.
• Police officers may impede the interview process by interrupting witnesses, asking short specific questions that may not elicit critical information, asking questions not relevant to what the witness is currently describing, and using inappropriate sequences of questioning.

Dynamics of Interview

• Some police may be insensitive to the dynamics in a witness interview
• Demand characteristics: pressure to give the “correct” answer
• Negative effect of leading question
• Insensitivity to consequence of errors in their own interview

Witness Recall Examined For:

• Amount of information reported
• Type of information reported
• Accuracy of information

Witness Recognition Examined For:

• Accuracy of decisions
• Types of errors made

Witness Contamination

• Witnesses can be "contaminated" by information from other witnesses, leading to "memory conformity."

The Effect of Misinformation

• Misinformation occurs when a witness is provided with inaccurate information about an event after witnessing it and incorporates the "misinformation" in their later recall.
• Subtle differences in phrasing can bias witness responses and cause inaccurate reporting (e.g., using "smashed" instead of "hit").

Explaining the Misinformation Effect

• Theories explaining the misinformation effect:
  • Misinformation acceptance hypothesis: Brain likes to fill in when we miss information, and uses it for recall
  • Source misattribution hypothesis: Where get mixed up as to where we saw the information
  • Memory impairment hypothesis: Need to be paying attention to remember details

Interviewing Aids

• Procedures used in the investigative process to aid eyewitness recall include:
  • Hypnosis.
  • Cognitive interview.
  • Enhanced cognitive interview.

Hypnosis

• Hypnosis facilitates the retrieval of memories, but the accuracy may vary.
• More information is recalled when participants close their eyes.
• Not admissible in court

Cognitive Interview

• Based on memory retrieval techniques:
  • Reinstating the context (think back to that day, close your eyes and think).
  • Reporting everything.
  • Reversing order.
  • Changing perspective.

Enhanced Cognitive Interview

• Components added to the original cognitive interview:
  • Rapport building.
  • Supportive interview boundaries.
  • Transfer controls.
  • Focused retrieval.
  • Witness-compatible questioning (catering to who you are interviewing, using different techniques for different ages).

Recall of Perpetrator

• Descriptions of the perpetrator by witnesses often lack detail and accuracy.
• Gender, hair, clothing, and height are the most frequently described features.

Recognition Memory

• Recognition memory can be tested through lineups, video tape of lineup, walk-bys, and stand-in lineups.

Lineup Identification

• Witnesses are frequently asked to identify a perpetrator from a lineup containing the suspect placed among known innocent individuals called foils or distractors.

Estimating Identification Accuracy

• Two types of lineups are used to predict accuracy:
  • Target-present lineup, which contains the perpetrator.
  • Target-absent lineup, which contains an innocent suspect.

Lineup Presentation Procedure

• Lineup presentation procedures vary:
  • Simultaneous lineup: All members are presented together.
  • Sequential: Members are presented serially.
  • Show-up: Only the suspect is shown.
  • Walk-by: Witness is taken to a public location suspect where the member is likely to be.

Type of Lineup Judgments

• Two types of judgments are used in lineup procedures:
  • Relative judgment: Comparing lineup members to one another and choosing the one who looks most like the perpetrator.
  • Absolute judgment: Each member is compared to the witness's memory of the perpetrator.

Effectiveness

• Sequential lineups increase the likelihood of a correct rejection compared to simultaneous lineups.
• However, recent research suggests that this superiority may be due to methodological factors.

Biased Lineups

• Biased lineups suggest who the police suspect, thereby influencing the witness's identification.
• Types of biases that increase false identification include foil bias, clothing bias, and instruction bias.

Voice Identification

• Longer voice samples lead to greater accuracy.
• Voices with an accent that are whispered are more difficult to identify.

Multiple Identification

• If witnesses accurately identify multiple features of the suspect, the suspect is more likely to be guilty.

Witness Confidence

• A small positive correlation exists between a witness's confidence and identification rate.
• This correlation increases when identification decisions are made quickly.
• Confidence can be manipulated with post-identification feedback.
• Mock jurors do not appear sensitive to "inflated confidence."

Estimator Variables

• Age: Younger and older adults (over 60) produce lower correct identification rates from target-present lineups, and older adults have lower correct rejection rates from target-absent lineups.
• Race: Witnesses are able to remember faces of their own race more accurately than faces of other races; this is known as the cross-race effect. The cross-race effect may relate to attitudes, physiognomic homogeneity, or interracial contact.
• Weapon focus: Witness attention focuses on the perpetrator's weapon rather than the perpetrator themselves. This may be explained by the cue-utilization hypothesis (emotionally charged cues are better remembered) or the unusualness hypothesis (unusual things compared to things that we see everyday.

Eyewitness Expert Testimony

• There is controversy regarding the application of research on eyewitness issues to the court.
• Points of contention include the reliability of results across studies, the applicability of laboratory simulations to real-life situations, and a lack of theoretical basis.

Identification Guidelines

• The person who conducts the lineup should not be aware of the suspect.
• Eyewitnesses should be informed that the perpetrator may not be present in the lineup.
• Suspects should not stand out. A clear statement regarding witness confidence should be taken at the time of identification.

Sophonow Inquiry: Recommendation for Canada

• The lineup procedure should be videotaped or audiotaped.
• Officers should inform the witness that it is just as important to clear innocent suspects.
• Photo lineups should be presented sequentially.
• Officers should not discuss a witness's identification with them.