Factors affecting the accuracy of eyewitness testimony Flashcards
What is eyewitness testimony?
Evidence provided by those recalling an event who were present when it took place
What are the three factors affecting eyewitness testimony?
Schema, misleading questions, anxiety (and post-event discussion)
What is schema?
A set of information built of the world that is constantly being changed and adapted
How did Bartlett say schema influenced eyewitness testimony?
Memories are not complete “snapshot” representations of what happened, they are inaccurate reconstructions of the event instead. These ‘memories’ are influenced by active schemas, which are based on our past experiences, moods and attitudes. When we have gaps in our knowledge and memories, our schema fills it with things from our past experiences or culture.
What was Bartlett’s “War of the Ghost’s” study?
A Native Indian story was found to Western participants.
After a short while, the participants were told to recount the story. It was found that they had filled gaps in their memory of the story with Western-cultured aspects, e.g. instead of bows and arrows there were guns. Bartlett concluded that participant’s schemas had filled in
the necessary gaps with things from their own past
What forms does misleading information commonly take?
Leading questions and post-event discussion
What are misleading questions and how do they reduce the accuracy of eyewitness testimony?
Questions that suggest an answer; Influences the individual to give an answer that is desired by someone and not necessarily the truth of what happened
What was the procedure used by Loftus and Palmer in their first study?
Participants were shown 7 video clips of car crashes and after each one participants wrote an account of the accident and answered specific questions, the key question being to estimate the speed of the cars (five conditions)
What were the five conditions used by Loftus and Palmer and what were the findings for each one?
Mean estimates used: Contacted: 31.8mph Hit: 34.0mph Bumped: 38.1mph Collided: 39.3mph Smashed: 40.8mph
Who were Loftus and Palmer’s original participants?
45 university students
What was the procedure of Loftus and Palmer’s second study?
150 students watched a video of a car crash. 50 were asked the key question using “smashed” and 50 with the word “hit” and a control group who weren’t asked at all. One week later they were asked if they had seen any broken glass (there wasn’t any)
What were the results of Loftus and Palmer’s second study?
Smashed: 16 said yes 34 said no
Hit: 7 said yes 43 said no
Control: 6 said yes 44 said no
Therefore misleading information in the form of misleading questions can affect memory recall
Who studied post-event information?
Loftus and Pickrell
What procedure did Loftus and Pickrell use and what were their results?
120 students who had visited Disneyland were divided into four groups and instructed to evaluate advertising, fill out a questionnaire and answer questions about a trip to Disneyland; 30% in condition 3 (advert containing BB) and 40% in condition 4 (fake advert and cardboard cut-out of BB) said they had met Bugs Bunny - an impossible event because he is a Hanna-Barbara character
What is the main criticism of EWT research?
It often uses artificial scenarios that have no emotional involvement for witnesses, which lacks ecological validity because real-life crimes often create high levels of anxiety that can greatly affect recall
Who argued for a “weapons effect” and what does this involve?
Loftus et al.; Witnesses to violent crimes focus on the weapon being used rather than the culprit’s face, which negatively impacts the ability to recall important details
What does Deffenbacher suggest? Explain this
The Yerkes-Dodson inverted-U hypothesis; moderate amounts of anxiety improve the detail and accuracy of memory recall up to an optimal point, after which further increases in anxiety lead to a decline in the detail and accuracy of recall
What does most research suggest about the Yerkes-Dodson IUH?
It is difficult to reach any firm conclusions
What did Loftus et al. find in relation to the weapons effect?
If a person is carrying a weapon, witnesses focus on the weapon rather than the person’s face, suggesting that anxiety can divert attention from important features of a situation
What did Freud suggest that anxiety causes and why?
Repression: Anxiety hinders the recall of memories because forgetting is motivated by the traumatic content of the memory, barring access to the memory to protect individuals from the emotional distress they would cause
What did Oue et al. find?
People who were anxious from viewing emotionally negative events recalled less details than participants witnessing emotionally neutral events, suggesting anxiety reduces witnesses’ fields of view
What did Deffenbacher find when he reviewed his findings?
They were over-simplistic, and his results actually supported an amended version of the catastrophe theory; performance increased up to extreme levels of anxiety, and then sharply dropping
What other mediating factors effect EWT?
Age and personality factors could also play a part in how anxiety affects recall
What did Yuille and Cutshall find?
Looked at real crime witnesses and found high stress levels led to very accurate recall (criticism of Yerkes-Dodson)
