Lecture 2: Eyewitness Testimony and Memory Flashcards
1
Q
What are the 3 stages of memory?
A
- encoding: gathering info and putting it in a form that can be held in memory
- storage: holding encoded info in the brain over time
- retrieval: accessing and pulling out the stored info at a later time
2
Q
Do our brains objectively record data?
A
- No, memory is made up of subjective interpretations—some info is more salient than others
- Old information has more influence than new
- Belief perseverance
- Memory traces fade over time
- It is surprisingly easy to distort and/or create memories
- Memory is strongly influenced by our views, attitudes and beliefs at the time of recall
- Sensory input is influenced by expectation
- Psychologists have difficulty telling the difference between real and implanted memories
3
Q
What are heuristics and cognitive biases?
A
-
Heuristics are shortcuts, simplified processing
- Filling in the blanks w/ pre-existing knowledge
-
Cognitive biases are mental errors
- Often caused by heuristics
4
Q
What 4 criteria are jurors given for evaluating eyewitness testimony?
A
- (1) The reliability of the witness
- e.g. Was the eyewitness’s ability to observe the event impaired?
- (2) The circumstances under which the observation was made
- e.g. How good was the visibility? What was the duration of the observation?
- (3) The description of the observation given
- e.g. How specific was it? Did the eyewitness express certainty?
- (4) The circumstances of the procedure used to obtain an identification
- e.g. How much time had elapsed between the observation and identification?
- Was the lineup procedure fair?
5
Q
Is there any correlation between eyewitness confidence and accuracy?
A
- There is a very weak correlation (+0.10) between confidence and accuracy—might not be an actual correlation at all
- Jurors tend to not believe witnesses whose memory for trivial details is poor, but these are actually usually the best (most accurate) witnesses
- Why? The more details remembered about the scene, the less details remembered about the face + victim
- Discussion or questioning about events can alter or add to memory
6
Q
How do we distinguish between real and suggested memories?
A
Subtle differences:
- Actual memories tend to include more sensory details
- Suggested memories include greater references to cognitive processes
Real and suggested memories are often indistinguishable b/c:
- Suggested memories are retrieved just as quickly and w/ as much confidence as real memories
- Equally likely to be maintained following contradictory info
7
Q
Who is susceptible to misinformation and why?
A
- The relationship is complex—the most susceptible were those with either the best or the worst memory abilities
- Why? The incorporation of misinformation into memory requires two opposite memory demands:
- 1) Forgetting the original information → bad memory
- 2) Remembering the suggested → good memory; overconfident
8
Q
What causes misinformation to be integrated into memory?
A
- The act of recollection itself
- Specifically? Encouraging the remembering of misinformation reduces access to the original info
- Which happens a lot in the legal process when you have to go to the police several times, have to talk to lawyers, etc.
- Repetition also increases your confidence
9
Q
What is the cross-race effect (or “own-race bias”)?
A
- When it’s harder for people to recognize the faces of people outside their own racial group vs. w/in their own racial group
- Maybe b/c we encode features of people from other races more superficially
- Or b/c we have more experience + contact w/ people our own race → develop better rules for making useful distinctions between faces
- But our ability to recognize faces from other groups increases w/ increased contact
10
Q
Explain the Morgan et al. (2004) study on effects of stress on memory.
A
- Found that the rate of correct identifications (after a mock interrogation) was significantly higher for participants in the low stress vs. high condition
- High stress condition produced significantly more false positives
- Further studies have shown that high stress impairs memory
11
Q
What is the weapon focus effect?
A
- If eyewitnesses see a perpetrator holding a gun or a knife, their ability to recognize the assailant is impaired
- More focus on weapon since it’s more dangerous → less likely to remember details of the assailant
12
Q
What are the arousal/threat hypothesis and unusual item hypothesis?
A
- arousal/threat hypothesis → the danger imposed by weapon is an important part of this effect
- unusual item hypothesis → if you see a bank robber holding a goose hostage, your attention would be on the goose, not b/c it’s dangerous but b/c it’s unusual
13
Q
Explain the Loftus & Palmer (1974) study on the effects of leading questions.
A
- Ps watched a video of a minor fender bender
- 5 groups of Ps were asked separate Qs:
- How fast were the cars going when they _____ each other?
- Smashed vs. contacted; smashed on average over 10km faster
- Implications for research: Ps remembered the car as going faster depending on the language/verb being used
- Real life implications? Might be harsher sentences if witnesses report the car as going a faster speed, depending on how the police question them, where there shouldn’t be this difference
- Police officers should strive for more open-ended questions
14
Q
What is the misinformation effect?
A
- Happens when a person’s recall of episodic memories becomes less accurate because of post-event information
- Depends on an individual’s suggestibility + misattribution
15
Q
What is the source misattribution hypothesis?
A
- When info is retained in memory but the source of the memory is forgotten; i.e. confusion as to the source of details
- Attributes information to wrong source
- “Is this something I actually experienced? …or was I told about it?”
16
Q
What is the misinformation acceptance hypothesis?
A
- When people guess answers based on what they heard most recently and/or what they think the police or lawyer wants to hear
- And then begin to believe that info
- Especially if authority figures give subtle cues
17
Q
What is unconscious transference?
A
- When a face that is familiar from one context is transferred to the scene of a crime
- e.g. Identifying someone who closely resembles the perpetrator or someone else who was near the scene of the crime
18
Q
Explain the Loftus (1979) study about misleading cues including stop signs and yield signs.
A
- Ps came in + watched a video:
- A silver car is parked at a yield sign vs. stop sign
- Another car drives up and passes the silver car, turning a corner
- After a few seconds, you hear a crash/shattering glass sound
- Ps do a filler task, then asked Qs
- “Did another car pass the silver car while it was stopped [answer IS yes] at the stop/yield sign?”
- 4 different conditions: stop vs. yield + consistent vs. inconsistent
- Ps do another filler task, then asked whether they had seen certain pictures/stills from the video
- Inconsistent (misinfo effect group): 41% correct identification
- Higher amount of false positives + not recognizing things they actually have seen
- Consistent (control group): 75% correct identification
- Inconsistent (misinfo effect group): 41% correct identification
- Real world application: running a stop sign would carry much heavier penalties than running a yield sign—you would hope police actually go back to the site of the crime to confirm what kind of sign it was
19
Q
What is retrieval inhibition?
A
Selectively retrieving only some aspects of a scene “inhibits” recall for other aspects of that same scene
20
Q
What are hypnotic hypernesia and memory hardening?
A
-
hypnotic hypernesia: People usually recall more information when they are hypnotized than when they are not hypnotized
- But more info isn’t necessarily better info
- memory hardening: Once an event is vividly imagined under hypnosis, a witness may become confident that the memory is true
21
Q
What are the 4 admissibility guidelines for information obtained under hypnosis?
A
R v. Clark (1984): admissibility criteria for hypnosis-induced evidence
- (1) The hypnotic interview should be conducted by an independent and qualified professional.
- (2) The hypnotist should only be given minimal information to perform the interview.
- (3) The hypnotist should try his or her best to avoid any leading questions, suggestive body language, or any other potentially biasing interview techniques.
- (4) The interview should be recorded.
These were overturned in 2007 b/c they were found to be insufficient
22
Q
What are scripts?
A
Widely held beliefs about sequences of actions that typically occur in particular situations
23
Q
Explain the Holst & Pezdek (1992) study on the effects of scripts on recall of a crime.
A
- Ps heard a mock trial of a defendant accused of convenience store robbery
- Elements such as pulling out a gun + demanding money weren’t present
- But Ps ended up recalling these events happening
24
Q
What are system variables and how can they affect memory?
A
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System variables: Variables that are part of the Justice System, over which the police and justice system have at least some control
- e.g. procedures used to select members of line-up, the presentation, instruction given to witness, conditions in the interview, interview style
- How people respond to these questions can be controlled by interview style
- Closed or leading questions: “…when the car smashed…”
- vs. Open-ended questions: “What did you see?”
25
Q
What are estimator variables and how can they affect memory?
A
- Estimator variables: outside the control of the legal system (e.g. who witnesses a crime, if the victim is a different race than the criminal)
- Their impact on the accuracy of an identification can only be estimated
- e.g. physical and temporal context of the crime (distance, lighting, duration, weather), age + gender (both of suspect + witness themselves), emotional state, witness eyesight
26
Q
How can perception influence a person’s memory?
A
- We perceive events selectively and use imagination (familiarity/plausibility) to fill in the gaps
- Central vs. peripheral details; change blindness
27
Q
How can plausibility and familiarity contribute to misinformation effects?
A
- Plausibility is the apparent validity of the statement → increases the perceptions that an experience is correct
- Familiarity is having knowledge of the subject → provides additional details about a possible event
- Our plausibility is usually compared against our familiarity; e.g. What does a bank robber look like?
- Even if the robber didn’t have a gun or wasn’t wearing a balaclava, b/c these things are familiar, they’ll seem more plausible to you
28
Q
Explain the Loftus (1979) study on impact of eyewitnesses for conviction rates.
A
- Really weak robbery/murder case (insubstantial evidence)
- Conviction rate: 18% under normal circumstances
- Add an eyewitness → Conviction rate jumps to: 72%!
- Discredit the witness → Conviction rate falls to: 68%!
- Basically not statistically different compared to having an eyewitness
29
Q
Explain the Lindsay, Wells, & Rumpel (1981) study on the influence of confidence of eyewitnesses on jury’s belief.
A
- Viewing conditions vs. accuracy of witness
- Witnesses were much better at identifying the thief if the conditions were good (75% correct) vs. moderate (50%) or poor (35%)
- However, the confidence levels of all three groups were equivalent (83%)
- For jurors, they believed the witnesses in the poor + moderate conditions at around 60% (conviction rate) and 78% for the good condition
30
Q
What are 3 reasons why confidence is not a good indicator of accuracy?
A
- (1) Confidence increases over time; witnesses have to relive the same moment over and over, giving the same story + looking at the same photographs
- (2) post-identification feedback effect: tendency for biased feedback to distort the memory of eyewitnesses
- e.g. If you’re told you identified the right person → thinking you had a better view of the criminal + had paid more attention during the crime
- (3) cognitive dissonance: once you commit yourself to a particular course of action, you will become motivated to justify that course of action
- → once you’ve identified someone, uncertainty will make you uncomfortable
- → increase your level of certainty to reduce dissonance
