Factors Affecting Accuracy of Eyewitness Testimonies Flashcards
Eyewitness Testimony
the details people can remember from events such as accidents and crimes which they have observed.
What two factors can affect EWT
Misleading Information, and Anxiety
Misleading Information
incorrect information given to an eyewitness usually after the event.
What two forms can Misleading Information take
leading questions, and post-event discussions
Leading Questions
a question which suggests a certain answer due to the way it is worded.
Key Study of Leading Questions
Loftus and Palmer (1974). Had 45 participants watch film clips of car accidents and then asked questions. In the critical question (leading question) they were asked to describe how fast the car travelled. There were five groups who were each given a different verb in this question, hit, contacted, bumped, collided, or smashed. Mean estimated speed was calculated. Contacted = 31.8mph, and smashed was 40.5mph. It biased their recall of event.
Explanation for how leading questions affect EWT
Response-Bias suggests word of question has not effect on memories but influence how decide to answer. Substitution proposes the words change the participants memory. Those who originally heard smash were more likely to report seeing broken glass than those who heard hit (no broken glass). (Loftus and Palmer).
Post-Event Discussions
Occurs when there is more than one witness who discuss experience with other witnesses influencing the accuracy of recall.
Key Study for Post-Event Discussions
Gabbert et al (2003). Each participant watched a video of same crime but filmed from a different view than their partners. Pairs then discussed what they had seen. 71% mistakenly recalled aspects of event they did not see in video but picked up in conversation. 0% in control group where no discussion.
Explanation for Post-Event Discussion
Memory Contamination suggests when discuss the event becomes altered or distorted because combine information from other witnesses with their own memories. Memory Conformity is when witnesses go along with each other, either for social approval or because they are right but memory is unchanged.
(M) Strength
Important use in CJS
Loftus (1975) believes leading questions distort memory so officers need to be careful how they phrase questions.
Understand impact to then limit this.
However… as psychologists asked to be expert witness it can cause victim testimonies to no longer be believed, which is especially detrimental on rape survivors, and hinders convictions of guilty people.
(M) Weakness (L)
More accurate for some and not other aspects.
Sutherland and Hayne (2001) found recall of more central details was better than peripheral when asked leading questions on a clip they watched.
Focus on central aspects more so more resistant which weakens validity of substitution.
However… did still affect response to not paying attention to and in real life when crime is happening may not be focused on central details due to stress and shock so real life recall may be impacted.
(M) Weakness (C)
Contradicts memory conformity.
Skagerberg and Wright (2008) showed film clips where one had mugger’s hair as dark brown and one had it as light brown. They discussed with people who watched opposite version to them and reported a blend e.g. medium brown hair.
Memory was distorted decreasing validity.
However… Bodner et al (2009) suggests discouraging participants from sharing information makes it more accurate.
Anxiety
EWT are often used after violent crimes which cause high anxiety which impacts EWT but as no research into this creates an emotional impact they have low validity.
Anxiety can have a negative Impact
Creates physiological arousal in body which prevents paying attention to details making recall worse. One approach is to look at effect of weapons as it leads to them focusing on the weapon and reduces the recall of other details (weapon’s focus effect).
Key Study for Negative Impact
Johnson and Scott (1976). Participants believed taking part in lab study but in waiting room in a low anxiety condition heard a casual conversation in next room and man walked out with pen and grease on hands. In high anxiety condition heard a heated argument and breaking glass and man walked out with knife and blood on hands. Had to pick the man from 50 photos 49% who saw pen man identified him but only 33%. Tunnel theory argues enhanced memory for central aspects and weapons focus effect could explain this.
Anxiety can have a Positive Impact
The fight or flight response is triggered which increases alertness which improves memory of event and so are more aware of situation.
Key Study for Positive Impact
Yuille and Cutshall (1986). Conducted study of actual shooting in a gun shop in Vancouver which left thief dead. 13/21 took part. Interviewed 4-5 months after which was then compared to police interview at the time. Asked to rank how stressed they felt and if there were any emotional issues since. Little changed and still very accurate. Those with highest level were more accurate. Suggests anxiety enhances it.
Positive and Negative Effect
Yerkes and Dodson (1908) found relationship between emotional arousal and performance which looked like inverted U (Yerkes and Dodson’s Law). Low levels of anxiety help memory recall but there are optimum levels for the maximum accuracy but if experience more anxiety than that then rate declines.
(A) Strength (W)
Research support for weapons focus.
Johnson and Scott’s showed that when there was a weapon people focus on that and have poor recall of other details.
Increased anxiety cause tunnel vision.
However… may not have focused on it due to fear, Pickel (1998) found there was significantly poorer recall in the unusual conditions of raw chicken and handgun regardless of if they were dangerous. Weapons focus due to unusualness.
(A) Strength (N)
Research support for negative effect.
Valentine and Mesout (2009) monitored heart rate of those who went into London Dungeon and found those who experienced higher anxiety had worse recall.
Suggesting has negative effect on memory.
Furthermore… Peter’s (1988) found patients could recall the researcher better when they were present when a nurse gave them a needle injection than the nurse.
(A) Strength (P)
Evidence for positive effect.
Christianson and Hubinette (1993) interviewed witnesses to a bank robbery and found those directly involved had better recall than those but the overall recall rate was 75%.
Ecological validity gives generalisability and enhances it.
However… interviewed several months after so may be impacted e.g. post even discussions. Impossible to assess.
