Eyewitness Testimony (Forensic Psychology)

Flashcards covering key vocabulary and concepts from an eyewitness testimony lecture.

How is memory processed?

Information enters through the sensory system, briefly registering in sensory memory; selective attention moves information into STM, and sufficient rehearsal moves information into LTM.

Memory Stages

Attention, Encoding, Sensory Memory, Short-Term Memory (STM), Long-Term Memory (LTM).

Archival Data

Police reports.

Field Studies

Accompanying police to crime scenes and interviewing witnesses AFTER police.

Most common research paradigm used to evaluate eyewitness testimony

Laboratory simulations, where an unknowing participant views a critical event (crime)

Laboratory Simulations

An unknowing participant views a critical event.

Categories of Eyewitness Memory Retrieval

Recall Memory or Recognition Memory

Variables in Eyewitness Studies

Estimator variables and system variables.

Estimator Variables

Variables present at the scene that cannot be changed (e.g., age, intoxication, weapon presence).

System Variables

Variables that can be manipulated to increase eyewitness accuracy (e.g., lineup type, interviewing procedure).

Dependent Variables in Eyewitness Studies

Recall of the event, recall of the perpetrator, and recognition of the perpetrator.

Open-Ended Recall

Witnesses provide all they remember about an event without interruption.

Direct Question Recall

Witnesses are asked specific questions about an event.

Recall Memory

Reporting details of a previously witnessed event or person; describing what the perpetrator did.

Recognition Memory

Determining whether a previously seen item or person is the same as the one currently being viewed; identifying the perpetrator's voice.

Open-Ended Recall (Free Narrative)

Witnesses are asked to write/state all they remember without questioning.

Direct Question Recall

Witnesses are asked a series of specific questions about the crime.

Lineup

A set of people presented; the witness must state if the perpetrator is present and, if so, which person it is.

Memory Conformity

When what one witness reports influences what another witness reports

Misinformation Effect

A witness who is presented with inaccurate information after an event will incorporate that misinformation into a subsequent task.

Misinformation Acceptance Hypothesis

Explanation for the misinformation effect. The incorrect information is provided because the witness GUESSES what the officer wants the response to be.

Source Misattribution Hypothesis

Explanation for the misinformation effect. Witness has two memories (original + misinformation) but cannot remember where each originates.

Memory Impairment Hypothesis

Explanation for the misinformation effect. The original memory is replaced with the new, incorrect information leading to misinformation effect.

Cognitive Interview

Interview procedure based on memory storage and retrieval principles.

Enhanced Cognitive Interview

Interview procedure including social dynamics principle + memory retrieval principles used in original cognitive interview.

Suspect

The person the police suspect committed the crime.

Perpetrator

The guilty person who committed the crime.

Foils (Distractors)

Members known to be innocent.

Fair Lineup

Lineup where the suspect does not stand out.

Target-Present Lineup

Lineup that contains the perpetrator.

Target-Absent Lineup

Lineup that does not contain the perpetrator.

Simultaneous Lineup

All lineup members are presented at one time.

Relative Comparison (or Judgement)

Witness compares lineup members to one another. Person who looks MOST like the perpetrator is identified.

Sequential Lineup

Lineup members are presented serially; witnesses must decide yes or no before seeing another member.

Absolute Judgement

Witness compares each lineup member to their memory of the perpetrator.

Showup

Shows one person to the witness: the suspect. Asks yes/no?

Walk-by

Occurs in a naturalistic environment. Police take witness to public location where suspect is likely to be + ask whether they see the perpetrator.

Cue-Utilization Hypothesis

When emotional arousal increases, attentional capacity decreases.

Similarity-To-Suspect

Matches lineup members to the suspect’s appearance.

Match-To-Description

Sets limits on the number of features that need to be matched based on witness’s description.

Biased Lineup

A lineup that “suggests” whom the police suspect.

Cross-Race Effect

Phenomenon of witnesses remembering own-race faces with greater accuracy than those of other races.

Weapon Focus

Witness’s attention is focused on the perpetrator’s weapon rather than on the perpetrator.

Why is it bad when police officers ask a predetermined + random list of questions?

Questions are NOT related to a witness’ present testimony. They can mix auditory + visual memories, miss a relevant question + lose out on richness of witness answer.

Why is mixing auditory/visual questions bad?

Decreases recall by 19%

Why is interrupting the witness not good during a police interview?

Limits amount of info witness has in their collective memory

Why are asking short/specific questions in police intterview bad?

Requires more superficial level of concentration than open-ended questions; very short answers.

Why is missing a relevant question bad during a police interview?

Could miss a descriptor (e.g a tattoo) that could narrow the suspect pool if not asked about.

Fisher et al. (1987) Findings

Police officers' approach limited their ability to collect complete and accurate information.

Memory Conformity

When one witness’s account influences another’s. Occurs if witnesses communicate with each other OR come to learn what the other has reported.

Misinformation Effect

Introducing an inaccurate detail AFTER the event leads them to report that inaccurate detail when questioned later.

Loftus & Palmer (1974) Experiment

University students watched a videotape of a car accident; word used to describe accident influenced their responses.

Lineup Identification

Typical method used to gain proof about the identity of a perpetrator.

Purpose of Lineup Identification

Reduces uncertainty of whether suspect is the perpetrator, increases likelihood suspect is the perpetrator, informs police about physical characteristics of perpetrator.

Strategies used to decide on physical appearance of lineup distractors

Similarity-To-Suspect + Match-To-Description

Research Paradigms for Lineup Studies

Target-Present Lineups + Target-Absent Lineups

Distractors

Lineup members known to be innocent of the crime.

Lineup Techniques

Done with live people, photographs OR videos. Done simultaneously OR sequentially.

Two Conditions Required For Lineup Research

Police have arrested the right person, the guilty suspect OR Police have arrested the wrong person, an innocent suspect.

Target-Present Lineup

Contains a picture of the perpetrator.

Target-Absent Lineup

Perpetrator’s picture is substituted with another photo.

Only Correct Decision in Target-Present Lineup

Correct identification.

Only Correct Decision in Target-Absent Lineup

Correct rejection.

Photo Arrays

Using photos instead of live persons.

Problems with live simultaneous lineups

Results in relative judgement, police sometimes give cues + witnesses assume culprit is in the lineup.

False Positive Rate for Live Simultaneous Lineups

43%

Rate of False Positives for Live Sequential Lineups

17%

Simultaneous Lineup

Witness sees suspect + foils at the same time. Results in relative judgement.

Sequential Lineup

One person is viewed at a time, witness answers yes/no before proceeding onto next person. Results in absolute judgement.

Benefits of photo arrays

Less time-consuming to construct (mug shots v. finding live persons), portable (can bring photo array to witness), no right to counsel for perpetrators (unlike live lineups), suspect behaviour does not matter, witness LESS anxious.

Rejection rates for video arrays

DID NOT DIFFER across live and video-recorded lineups, except when witnesses requested additional viewings (more likely to guess).

Rejection Rates for Simultaneous Lineups

42%

Rejection Rates for Sequential Lineups

65%

benefits of video lineups v. photo arrays

Can enlarge faces + focus on particula features. Members can be shown walking, turning + talking.

Showup

Shows one person to the witness: the suspect.

Showup Challenges

Absolute judgements MORE LIKELY with a showup and can INCREASE likelihood of false identifications. Showups NEVER resulted in higher accuracy, even with biased lienups

Acceptable instances where showups can be used

Deathbed identifications; if suspect is apprehended immediately at OR near the crime scene.

Benefits of Showup

Suspect MORE LIKELY to be identified (76%) in.a showup vs. a photo array.

Foil Bias

When the suspect is the ONLY lineup member who matches the description of the perpetrator.

Clothing Bias

When the suspect is the only member wearing clothing similar to that worn by the perpetrator.

Instruction Bias

Police FAIL to mention to the witness that the perpetrator MAY NOT be present OR IMPLY that the perpetrator is present.

How to Improve Lineups

Person who conducts the lineup should not be aware of suspect’s identity, eyewitness should be informed culprit may not be present, suspect should not stand out, statement of witness confidence taken AT the time of identification.

Voice Identification Factors that INCREASE rates of identification

HIGHER with longer voice samples. MORE likely with laughter, familiar accent.

Voice Identification Factors that Decrease Rates of identification

Whispering, muffling or emotion. If the target voice occured later in a lineup. WORSE if speaker’s face is visible OR # of foils increased.

If witnesses report the suspect has an accent…

Witnesses LESS likely to provide as many accurate details as to how the perpetrator looked.

Are several identifications better than one?

Exposing witnesses to more than one lineup (e.g clothes v. face) increased the ability to determine the reliability of an eyewitness’ identification of the suspect.

Relationship between Eyewitness Confidence & Accuracy

Small correlation between witness confidence + accuracy, HEAVILY time-dependent.

Eyewitness Confidence & Accuracy @ First Identification

Particularly strong when target-present decision made (90%).

Eyewitness Confidence & Accuracy @ Repeated Identifications

When witness recall is REPEATED ⇒ ACCURACY declined but NOT confidence. Longer intervals associated with decreased confidence for incorrect answers, NOT correct answers + decreased accuracy.

How can witness confidence be manipulated?

Post-identification feedback + encouragement + repetition of identification (more often you express decision, greater your confidence becomes in subsequent reports).

Cross-Race Effect

Own-race faces produced HIGHER correct identifications + LOWER false positives than other faces. LARGER when intoxicated.

Explanations for the Cross-Race Effect

Attitudes, Phsysiognomic Homogeneity, Interracial Contact.

Attitudes (Explanation for the Cross-Race Effect)

People with fewer prejudicial attitudes more inclined to distinguish among members of other races.

Physiognomic Homogeneity (Explanation for the Cross-Race Effect)

Some races have less variability in their faces (LITTLE empirical support). BUT persons from other races may NOT pay attention or encode relevant features that distinguish between members of a particular race (e.g hair color for white people but nose bridge for Asians)

Interracial Contact (Explanation for the Cross-Race Effect)

MORE contact you have with other races, the BETTER you will differentiate them. SOME empirical support (white basketball fans).

Old Age (Estimator Variable)

Older adults (60+) appear LESS likely to correctly identify the perpetrator from a target-present lineup + MORE likely to incorrectly identify from target-absent. CONSISTENTLY underperformed compared to young ppl.

Younger Age (Estimator Variable)

Younger adults made more correct rejections when perpetrator also a young adult, but older adults did not show any own-age bias.

Weapon Focus

Term used to describe the phenomenon of a witness’ attention being focused on the weapon rather than on the perpetrator.

Expalantions for Weapon Focus

Arousal + Unusualness

Arousal (Weapon Focus)

Cue-Utilization Hypothesis. As emotional arousal increases, triggered by a visible weapon, attentional capacity decreases.