memory - eyewitness testimony Flashcards
What is meant by eyewitness testimony?
Eyewitness testimony (EWT) is the ability of people to remember details of events they have seen, such as crimes or accidents.
Outline a study into how leading questions can affect eyewitness testimony
- Loftus and Palmer (1974)
- They showed participants a film clip of a car accident, then asked them questions.
- One question was changed for different groups of participants- ‘about how fast were the cars going when they hit each other?’.
- For other groups, ’hit’ was replaced with ‘smashed’, ‘bumped’, ‘contacted’, or ‘collided’.
- Those given ‘smashed’ as their verb estimated a speed of 40.5mph.
- Those given ‘contacted’ estimated 31.8mph.
This shows how the phrasing of the question suggested how fast the car was going, and affected the participant’s answer (the response-bias explanation). Another explanation is the substitution explanation, where the question actually changes the witness’s memory.
In another study by Loftus, an additional question was asked- ‘did you see any broken glass?’ (there was none). Those given the ‘smashed’ question were more likely to say that they did see broken glass.
Outline research into how post-event discussion can affect eyewitness testimony
- Gabbert et al (2003)
- Studied participants in pairs. Participants watched a video of the same crime filmed from different points of view.
- This meant that each participant could see things that the other could not (for example, the title of a book being carried).
- Both participants discussed what they had seen before individually completing a test of recall, testing whether they (not them and their partner) had seen certain things.
- It was found that 71% of the participants mistakenly recalled aspects of the event that they did not see in the video but had picked up in the discussion.
- A control group, where there was no discussion, was also tested, and the number of errors made like in the experimental condition was 0%.
- The conclusion was that witnesses often go along with each other, either to win social approval or because they believe the other witnesses are right and they are wrong.
Evaluate research into factors affecting eyewitness testimony - lab
Studies such as Loftus and Palmer take place in labs, watching film clips, meaning that the emotional aspect of witnessing an accident or crime is not present. The experiments may therefore not tell us about how EWT may work in the real world.
Evaluate research into factors affecting eyewitness testimony - demand
Answers that participants may give may be due to them wanting to please the experimenter or guess what the experimenter wants from them (demand characteristics), so they may not answer in this way if recalling a real-life event. This reduces the validity of these findings.
Evaluate research into factors affecting eyewitness testimony - real-life application
The findings from these studies have potentially useful real-world applications- they can be used to amend how questions are asked in police interviews, for example. This strengthens the value of research into EWT.
Outline research showing anxiety has a positive effect on recall
- Yuille and Cutshall (1986)
- They studied a real-life robbery of a gun shop.
- 13 witnesses took part. They found that participants who reported experiencing the highest levels of stress were more accurate in their recall of details of the event than those that reported feeling less stressed (88% compared to 75%).
- This suggests anxiety can have a positive effect on EWT.
Outline research showing anxiety has a negative effect on recall
- Johnson and Scott (1976)
- Conducted a study using two groups of participants.
- One group heard an argument in an adjacent room, followed by glass breaking, then a man walked into the room holding a pen with grease on his hands.
- A second group saw the man walk in with a paper knife, with blood on his hands, to create a higher level of anxiety than the other condition.
- 49% of the ‘pen group’ later accurately identified the man in a line-up, compared to 33% of the ‘knife group’.
- This suggests anxiety has a negative effect on EWT, as witnesses will focus on the weapon as a source of anxiety and not concentrate on any other details (the tunnel effect).
What is the Yerkes-Dodson curve
Given the contradictory findings into anxiety’s effect on recall, it has been concluded that a moderate amount of anxiety can have a positive effect on recall, but once the level of anxiety gets too great, performance will decline.
Evaluate research into anxiety affecting eyewitness testimony - internal validity
The Johnson and Scott study may have actually tested surprise rather than anxiety over the weapon. Pickel (1988) found that participants were less accurate with recall when viewing a scene in a hairdressers including items such as a raw chicken (when compared to scissors, for example). The internal validity of Johnson and Scott is therefore in question.
Evaluate research into factors affecting eyewitness testimony - extraneous variables
Field studies such as Yuille and Cutshall cannot be controlled, for example how good the participant’s memories are generally, or whether they talked about what they saw. The research is therefore weakened as a result.
Who invented the cognitive interview?
Fisher and Geiselman developed the cognitive interview (CI) as a way of improving the accuracy of EWT.
Outline the 4 elements of the cognitive interview
1) Report everything: the witness recalls every possible detail of the event, because minor details may act as a cue to trigger more important information.
2) Reinstate the context: the witness is encouraged to return to the scene of the event (which could be real or imaginary), in the hope that this may provide cues to help recall detail. For example, imagining what the weather was like, what else happened that day, and so on.
3) Reverse the order of recall: for example, starting with the last thing they remember. This is to prevent the witness’s expectations of what happened interfering with their memory of what actually happened.
4) Change the perspective: for example, reporting what another witness or a victim may have seen. This is done to prevent reporting of the individual’s expectations, as in reverse the order.
What is the enhanced cognitive interview?
The enhanced cognitive interview was developed in 1987 and added further elements to the CI, focusing on the dynamic between the interviewer and witness- for example, when to maintain eye contact and how long for, asking open questions, and speaking slowly.
Evaluate the cognitive interview - time-consuming
The CI is very time-consuming, and many police forces don’t have the resources to properly use it, limiting its usefulness as an interview technique.
