eyewitness testimony Flashcards
what is an eyewitness testimony?
evidence given in court or a police investigation by someone who has witnessed a crime or accident
misleading information - leading questions
loftus and palmer (1974) experiment 1
- effect of leading questions of EWT accuracy
- 45 american students in 5 groups in independent design. all watched video of a car crash and then asked question about the cars speed. the verb was manipulated: “how fast were the cars going when they smashed/collided/bumped/hit/contacted with each other”
- speed was affected by verb used. when given the verb ‘smashed’ average speed was 40.5 mph, when given ‘contacted’ it was 31.8 mph
- the accuracy of EWT is affected by leading questions
loftus and palmer (1974) experiment 2
- 150 american students in 3 groups. watched 1 minute video of car accident then given a questionnaire. one group asked “how fast were the cars going when they smashed into each other”, another asked “how fast were the cars going when they hit each other”, the control group was not asked about the speed. a week later they were asked a series of questions, the main being “did you see any broken glass” (there was none in the clip)
- 32% of those given verb ‘smashed’, 14% of those given verb ‘hit’, and 12% of control group reported seeing glass
- memory for the earlier event was distorted by the leading questions one week prior
give a strength of loftus and palmer
1/1
done in a lab so was highly controlled, this reduces the chance of ev’s which then increases the validity of the results. so it is easier to replicate the research to see if the same results are achieved within a different population
give a limitation of loftus and palmer
1/2
questionable ecological validity, but questioning participants about daily events like a car crash appears to be a genuine measure of EWT. when watching the video of the car crash they saw every part from start to finish which rarely occurs in real life. so it can be argued the results don’t reflect everyday car accidents, so we can’t conclude eyewitnesses in real life accidents with a stronger emotional connection would react to leading questions similarly
give a limitation of loftus and palmer
2/2
lacks population validity. the 2 experiments used 45 then 150 uni of washington students. it could be argued that these are less experienced drivers who may be less accurate at estimating speeds. so results can’t be generalised to other populations like older or more experienced drivers who may have more accurate speed judgements so are less susceptible to learning questions
misleading information - post event discussion
gabbert et al (2003)
- 60 uni of aberdeen students and 60 older adults from a local community watched vid of girl stealing money from a wallet, they were either tested individually or in pairs. those in pairs were told they had watched the same video, but they had actually watched different perspectives of the same crime and only one watched the girl steal, they discussed the crime together. all then did a questionnaire about their memory of the event
- 71% of those in pairs recalled info they hadn’t seen and 60% said the girl was guilty despite not seeing the girl steal
- shows the issue of post event discussion and its affect on EWT
give a strength of gabbert et al
1/1
tested two separate populations and found little differences between the two. so the results have good population validity, letting us conclude post event discussion affects younger and older adults similarly
give a limitation of gabbert et al
1/2
results have questionable ecological validity. those in pairs witnessed different perspectives of the crime which is like real life, but they also knew they were taking part in an experiment so were more likely to pay close attention to the videos details. so the results don’t reflect everyday crime where witnesses may have less information
give a limitation of gabbert et al
2/2
the results provide insight into the effect of post event discussion on ewt accuracy, but we can’t conclude why the distortion occurs. it could be the result of poor memory where people put new info into their account of the event and can’t distinguish between the two. it also could be due to conformity and social pressures from their partner
anxiety
loftus (1979) / johnson and scott (1976)
- participants invited to lab and waited in the reception, the receptionist left. used independent design with two conditions. in ‘no weapon’ condition, participants overheard conversation then the target left and walked past participants with a pen. in ‘weapon’ condition, participants overheard argument and breaking glass then the target ran into reception with a bloodied letter knife. all then showed 50 photos and asked to identify the suspect, who they were told may or may not be in the photos
- those in ‘no weapon’ condition correctly identified target 49% of the time, compared to 33% of those in ‘weapon’ condition
- suggested those exposed to the knife had higher anxiety levels and were more likely to focus on the knife not the targets face, known as the weapon focus effect
give a limitation of the effect of anxiety on EWT
1/3
case study by yuille and cutshall (1986) contradicts loftus and weapon focus effect. they investigated anxiety in a real life shooting where one person was killed and another seriously injured. 13 of the 21 original witnesses aged 15-32 agreed to take part in the research 4-5 months later. they found these were accurate in their ewt 5 months later and little change was found from original testimonies, all major details stayed the same, only minor ones changed. witnesses didnt respond in biased ways to leading questions and anxiety had little effect on subsequent memory. this refutes the weapon focus effect and loftus, showing in real life cases of anxiety ewt accuracy isn’t affected
give a limitation of the effect of anxiety on EWT
2/3
research lacks ecological validity. although the participants waited in the reception outside the lab, they may have expected something would happen which could have affected the accuracy of their judgements. also, the results of case studies contradict loftus, suggesting the results don’t reflect real life extreme anxiety
give a limitation of the effect of anxiety on EWT
3/3
multiple ethical guidelines were broken. participants were deceived and not protected from harm. loftus exposed some participants to a man holding a bloodied knife which could cause extreme anxiety. this means participants may have left the experiment feeling stressed or anxious, even more so if they have personal experience with knife crimes
