Memory: Eye Witness Testimony - Factors Affecting The Accuracy

Question 1

Why is EWT important?

Answer 1

• Fruzetti et al (1992) has suggested that thousands of people are wrongly convicted because of inaccurate EWT every year
• In UK - Devlin report of 1976 found in England and Wales EWT was only form of evidence offered in court in many cases.

Question 2

What is EWT?

Answer 2

Eyewitness memory goes through 3 stages:
- Encoding
- Retention
- Retrieval
Things can go wrong at each of these stages, leading to unreliable memories

Question 3

How is encoding important in EWT?

Answer 3

Witness encodes into LTM details of event and people involved. May only be partial or distorted as crimes often happen quickly, at night and can be accompanied by rapid, complex and violent action.

Question 4

Why is it important to retain in EWT?

Answer 4

Witness retains info for a period of time. Memories may be lost or modified during retention, and other activities between encoding and retrieval may interfere with the memory itself.

Question 5

Why is retrieval important in EWT?

Answer 5

Witness retrieves info from storage. What happens during the reconstruction of the memory - e.g. the presence or absence of appropriate retrieval clues or the nature of the questioning may significantly affect its accuracy.

Question 6

What was Loftus and Palmers study in 1974?

Answer 6

45 students watched films of car accidents and then given a question-
‘about how fast were the cars going when they hit each other?’
Control group were given the verb hit. Other groups were given either ‘smashed’, ‘collided’, ‘bumped’ or ‘contacted’
- mean speed calculated for each group
They found - smashed = 40.8mph, collided = 39.3mph, bumped = 38.1mph, hit = 34mph, contacted = 31.8mph.

Question 7

What’s some evaluation of Loftus and Palmers study?

Answer 7

+ high control
+ good cause and effect - the IV affected the DV (the words caused the difference in recall)
- low ecological validity
- demand characteristics

Question 8

Why do leading questions affect EWT?

Answer 8

• Response-bias explanation - suggest the wording of the question has no real effect on the memory, but just influences how they answer. E.g. the word ‘smashed’ encourages ptps to choose a higher speed estimate.
• Substitution explanation - Loftus and Palmer conducted a second experiment and found the wording of a leading question actually changes the ptps memory of the film. Ptps who originally hear ‘smashed’ were more likely to report seeing broken glass (there was none) than those who heard ‘hit’. The critical verb altered their memory of the incident.

Question 9

What did Zaragose and McCloskey (1989) argue?

Answer 9

Ptps in lab studies of EWT give demand characteristics. This is because they guess the aims and try to give the answers they think the researcher wants to hear.

Question 10

Why is individual differences a problem?

Answer 10

There is evidence that older people are less accurate than younger people when giving eyewitness reports.
- Anastasi and Rhodes (2006) found people aged 18-25 and 35-45 were more accurate than people in the group 55-78 years. However, all age groups were more accurate when identifying people of their own age group (own age bias)

Question 11

What are the factors affecting EWT?

Answer 11

• memories are not accurate snapshots of events experienced; instead they are reconstructions based on schemas that were active at the time of recall
• schemas involve a readiness to interpret sensory info in a pre-set manner.

Question 12

What are schemas?

Answer 12

A mental representation that we have of something that helps us understand how things work. It is based on previous experience and helps use categorise info easily.
- an example of how schemas may effect EWT is seeing a women arguing with a man who has a knife, but remembering the man as having the knife due to holding sexist stereotypes of males being aggressive.

Question 13

How is misleading info a factor that can affect the accuracy of EWT?

Answer 13

Misleading info is info that suggests a desired response
- e.g. Loftus and palmers different verbs when asking how fast the cars were travelling when collided.

However - Yuille and Cutshall (1986) interviewed 13 armed robbery witnesses in Canada more than 4 months later, with 2 misleading questions - however, witnesses provided accurate recall which matched their original statements. This suggests that misleading questions may not completely affect the accuracy of the of EWT.

Question 14

How is Post Event info a factor that affects the accuracy of EWT?

Answer 14

Post event info is info added to a memory after the event has occurred.
- e.g. when more than one witness discusses a crime they both saw, their testimonies become containated because they combine info from their own memory with others memories. This can make it more inaccurate.
- there are two types of it (source monitoring theory and conformity theory)

Question 15

What is source monitoring theory?

Answer 15

Memories of the events are genuinely distorted. They can recall info about the event (accurate and inaccurate), but they can’t recall where it came from. Was it there own memory or did they hear it from someone else - known as source confusion

Question 16

What is conformity theory?

Answer 16

Eyewitness memories are not actually distorted, but instead, the recall changes only because they go along with the accounts of co-witnesses. They do this either to win social approval, or because they genuinely believe other witnesses are right and they are wrong

Question 17

What is some evidence to support post event discussion?

Answer 17

• Gabbert et al (2003) set up ptps in pairs and each pair watched a video of a crime but on their own. The crime was the same but the video was for 2 different points of view. This means one ptp can see element of the crime the other couldn’t have seen.
• then ptps paired and discussed the crime
• findings showed that 71% of ptps mistakenly recalled aspects of the event they could not have seen in the video but got from discussion.
• in the control group (who didnt have the post event discussion) they recalled 0% of things they could not see.
  This concludes there is a memory conformity happening where ptps go along with other witnesses

Question 18

How is Anxiety a factor affecting the accuracy of EWT?

Answer 18

• depending on the incident, you may have been anxious and this will affect your recall.
• research suggests that frightening situations may affect recall because, as well as weapon focus, stress itself may have a negative effect of performance.
  The Yerkes - Dodson Curve/Law (1908) says that performance (memory/recall) is best in moderately arousing conditions. Daffenbacher (1983) reviewed 21 studies and hypothesised the stress and performance follows an inverted ‘U’ curve. This suggests if there is too much anxiety their memory will be adversely affected

Question 19

What’s some evidence to support anxiety affecting EWT?

Answer 19

• Clifford and Scott (1978) - found that people who saw a violent film attack remembered fewer than 40 items of info about the event than a control group, who saw a less stressful version. Showing stress has a negative effect on recall.

Question 20

What is a study providing evidence for the Weapon focus affect affecting EWT?

Answer 20

• Loftus et al (1987) - ptps heard a discussion in another room - cond 1; ptps saw a man emerge holding a gen with grease on his hands, cond 2; man emerged holding a penknife covered in blood. When asked to identify the man from 50 photos, cond 1 = 49%, but cond 2= 33% accurate. This suggests the weapon may have distracted their attention - also helps explain why witnesses may have a poor memory of violent crimes.
• Loftus also found that when monitoring eye movements, they were physically drawn to the weapon and away from the persons face.

Question 21

What’s a real life study of the weapon focus affect?

Answer 21

• Yuille and Cutshall (1986) - showed that witnesses of a real life incident had remarkable accurate memories of a stressful and anxious event involving weapons.
• a thief stole guns and money in daylight, shot the store owner, who in turn shot and killed him. All of this happened in front of several witnesses. The witnesses recalled much important, accurate and detailed into and it corroborated with others (even after police used leading questions to try and throw them).
• this study shows there are cases of real life recall where memory for an anxious/stressful event is accurate and recall in lab studies (Loftus) may not have the same effect as real life.

Question 22

What is the evaluation of Loftus’ research?

Answer 22

• low ecological validity
• not all senses are involved - e.g. smell, sound, vision etc.
• research may have a different arousal level to what a real life situation will be.
• unrepresentative sample - Loftus used her students, this increases the likelihood of demand characteristics.
  + practical applications - e.g. in courts, convictions aren’t allowed where the evidence consists of only one EWT and the cognitive interview