Memory - The Eyewitness Testimony Flashcards
What is the eyewitness testimony?
- An eyewitness is someone who has seen or witnessed a crime, usually present at the time of the incident. They use their memory of the crime to give their testimony or a ‘reconstruction’ of what happened.
- Eyewitness testimony is the ability of the person who saw the crime to remember the detail of the events they have observed. They provide this evidence in court, with a view to identifying the perpetrator. Their accuracy can be affected by factors such as misleading information and anxiety.
Loftus and Palmer (1974)
- They arranged for participants (students) to watch film clips of car accidents and then gave them questions about the accident
- In the critical question (leading question) participants were asked to describe ‘how fast the cars were going when they hit each other?’ - this is a leading question because the verb ‘hit’ suggests the speed the car was going
- There were 5 groups of participants, with each being given a different verb in the critical question; ‘hit’, ‘collided’, ‘contacted’, ‘bumped’ and ‘smashed’
- The mean estimated speed for contacted was 31.8mph and for smashed was 40.5mph. The leading question biased the eyewitnesses’ recall of the event.
- According to the response-bias explanation, this is not because the wording has changed their memory; it just influences how they choose to answer. E.g. smashed makes them think faster, so they estimate higher.
- According to the substitution explanation, this is because the wording actually changes the participant’s memory of the film clip. This is supported by the finding that those who heard smashed were far more likely to report seeing broken glass (when there wasn’t any) than those who heard hit.
Gabbert et al (2003)
- They studied participants in pairs. Each participant watched a video of the same crime, but the crime was filmed from different points of view. This meant that each participant could see elements of the event that the other could not. For example, only one of the participants could see the title of a book being carried by a young woman. Both participants then discussed what they had seen before individually completing a test of recall.
- The researchers found that 71% of the participants mistakenly recalled aspects of the event that they did not see in the video but picked up in the discussion, the corresponding figure in the control group, where there was no discussion, was 0%
- Gabbert et al concluded 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 - this is called memory conformity
Post-event discussion
This occurs when a witness to a crime discusses it with another witness or someone else. This means that their eyewitness testimonies may become contaminated and therefore affects the accuracy of their recall of the event. This is because the witness combines (mis)information from other witnesses with their own memories.
Along with leading questions, post-event discussions contribute to inaccurate eyewitness testimonies.
Misleading information
Inaccurate information given after an event that affects the accuracy of the eyewitness testimony.
Evaluation of misleading information affecting eyewitness testimony - Supporting research and real-world applications
- Loftus and Palmer and Gabbert’s et al s studies
- Provide external validity for the explanations of inaccurate recall and help us to understand factors that impact the accuracy of the EWT - Loftus believes that leading questions can have such a distorting effect on memory that police officers need to be very careful about how they phrase their questions when interviewing eyewitnesses - research into the EWT is one area in which psychologists believe they can make an important positive difference to the lives of real people by improving the way the legal system works by appearing in court trials as expert witnesses.
- Provides external validity for the studies as they have proven to be helpful in improving the legal system and have ecological validity
Evaluation of misleading information affecting eyewitness testimony - Weakness of the studies
- Loftus and Palmer’s study involved watching films clips of accidents - this is different to witnessing an actual accident, as such clips lack the stress of real accidents, and this therefore does not account for the effect of emotions can influence on memory
- Therefore, the studies lack ecological validity as it is not fully representative of real-life eyewitness experience and so it is not fully generalisable - There is evidence that older people are less accurate than younger people when giving eyewitness reports. 18-25 and 35-45 year olds are more accurate than the 55-78 year old age group; but all age groups were more accurate when identifying people their own age
- This suggests that other factors affect the accuracy of the eyewitness testimony which the studies have not identified, and so these confounding variables could affect the internal validity of the studies
Evaluation of misleading information affecting eyewitness testimony - Weakness of the studies and undermining evidence
- The results of the lab experiments on EWT may be a result of demand characteristics - participants usually do not want to let the researcher down and want to appear helpful and attentive, so when asked a question where they don’t know the answer they may be more inclined to guess than they would in a real-life situation
- This suggests that the studies lack internal validity and that they are not fully generalisable to everyday situations of eyewitness testimonies - There are much greater consequences of being an eyewitness in real-life than in a lab (person could go to prison) and research has found that if participants thought they were watching a real-life robbery and that their responses would influence the trial, their identification of the robber was much more accurate
- This suggests that the studies lack ecological validity as there are other factors that increase accuracy of the EWT
How anxiety affects the EWT
- Is a state of emotional and physical arousal, including worried thoughts and feelings of tension. Physical changes include an increased heart rate and sweating.
- It is thought that anxiety affects the recall of eyewitnesses, but psychologists disagree on how.
- Some think anxiety has a negative effect on recall – the physiological arousal in the body prevents us paying attention to important cues, so recall is worse.
- Some think it has a positive effect on recall – the physiological arousal from anxiety triggers the fight or flight response which increases our alertness and improves our memory because we become more aware of cues in the situation.
What is tunnel theory?
Negative effects of anxiety -
- Tunnel theory argues that a witness’ attention narrows to focus on a weapon because it is the source of the anxiety. This leads to the weapon-focus effect where this tunnel focus then negatively affects the recall of the overall event.
The Yerkes-Dodson - Anxiety and the EWT
- This law states that performance improves with increases in arousal up to some optimal point and then declines with further increases.
- An increase in anxiety leads to an increase in physiological arousal. This heightens alertness and may improve our memory as we become more aware of cues in the situation.
- But if it gets too high; anxiety may cause you to lose focus and negatively affect performance.
(looks like the inverted U-theory)
Studies on the effects of anxiety - Johnson and Scott (1976)
- Participants in this study were left in a waiting area outside a laboratory whilst waiting for the ‘real’ study to start - while they were waiting one of the two situations occurred
- In the first situation (low anxiety) they overheard a discussion in the laboratory about equipment failure, followed by a man leaving the lab with a pen and grease on his hands
- In the second situation (high anxiety) participants overheard a heated discussion in the lab with the sound of breaking glass and crashing chairs, followed by a man leaving the lab carrying a paper knife covered in blood
- The participants were later asked to identify the man from a set of 50 photographs with the result that 49% correctly identified the man holding the pen, but only 33% could identify the man with the bloodstained knife
- Negative effects of anxiety on the eyewitness testimony
Studies on the effects of anxiety - Yuille and Cutshall (1986)
- They conducted a study of real-life shooting in a gun shop in Vancouver, Canada - the shop owner shot a thief dead
- There were 21 witnesses - `13 agreed to take part in the study, and the interviews were held 4-5 months after the incident and these were compared with the original police interviews made at the time of the shooting
- Accuracy was determined by the number of details recorded in each account
- The witnesses were also asked to rate how stressed they had felt at the time of the incident on a 7-point scale, and asked if they had any emotional problems since the event
- They found that the witnesses were very accurate in their accounts and there was little change in the amount or accuracy after 5 months, though some details were less accurate e.g. colour of items, age/height/weight estimates
- Those participants who reported the highest levels of stress were the most accurate (88% compared to 75% for the less-stressed group)
- Anxiety had a positive effect on the EWT
Studies on the effects of anxiety - Christianson and Hubinette (1993)
- 58 witnesses of 22 real-life bank robberies in Sweden were interviewed some time after the robberies - some of the witnesses had been onlookers or customers in the bank (low anxiety) and others were bank employees who had been directly threatened or subjected to violence during the robberies (high anxiety)
- They found that all witnesses showed generally good memories for details of the robbery itself (better than 75% accurate recall) those witnesses who were most anxious had the best recall
Evaluation of the effect of anxiety on the EWT - Undermining evidence and weakness of the studies
1) It has been suggested that the Johnson and Scott (1976) study is actually testing surprise rather than anxiety. The reason why participants may focus on the weapon may be because they are surprised at what they see rather than because they are scared. Pickel (1998) conducted an experiment using scissors, a handgun, a wallet or raw chicken as the handheld items in a hairdressing salon video. It would be assumed that the scissors would create low anxiety and low unusualness in this situation. They found that eyewitness accuracy was poorer in the high unusualness conditions – the raw chicken and the handgun.
- This suggests that there may be an alternative explanation for the weapon-focus effect. This finding suggests that it may be unusualness, rather than threat, that captures our attention, and therefore affects memory for the rest of the event. Therefore, the study may not actually tell us anything about the effects of anxiety on EWT at all.
2) In field and natural experiments researchers usually interview real-life eyewitnesses sometime after the event. In this time all sorts of things could have happened that the researcher has absolutely no control over, such as accounts in the media, interviews by police, post event discussion etc.
- It is possible that these extraneous variables may be responsible for the accuracy of recall. The effects of anxiety may be overwhelmed by these factors, and impossible to test by the time the participants are interviewed. Therefore, the studies can’t provide particularly strong support for the effects of anxiety on EWT.
