memory- EWT and post event discussion Flashcards
define eye witness testimony
the ability of people to remember the details of events such as crimes or accidents, which they themselves have observed
what can the affect the accuracy of eye witness testimony
misleading information- leading questions, post event discussion
effects of anxiety
misleading information
incorrect information given to the eyewitness usually after the event
leading question
a question asked in a way that suggests you have a preferred answer
what are the stages of memory relevant to EWT?
encoding to the LTM,
retention of memories (witness stores memories) ,
retrieval from LTM (witness recalls information at a later date)
what are the potential sources of error at each stage ?
encoding - poor viewing conditions, trauma responses eg. fight/flight/freeze
retention - memories may be lost or modified due to decay
retrieval - lack of appropriate cues, leading questions, post event discussion
leading questions research
loftus and palmer (1974)
loftus and palmer (1974) study aim
to investigate the effect of
leading questions on the
accuracy of eyewitness
testimony
describe the experiment done by loftus and palmer (1974)
45 participants were asked to watch video clips of car accidents, and asked what speed the car smashed/collided/ bumped/ hit/ contacted the car?
findings loftus and palmer (1974)
contacted mean estimate speed - 31.8 mph
smashed mean estimate speed 40.5mph
verb used in the leading questions biased the recall of car speed
explanation of findings loftus and palmer (1974)
response bias - ppt unsure of speed so adjusts estimate to fit question
substitution explanation- memory altered by critical verb so ppt recalls the accident differently
loftus and palmer secondary experiment
aim - to prove substitution explanation
loftus and palmer secondary experiment method
ppts shown a clip showing a car accident. They used 3 conditions - how fast were the cars going when they hit each other? ; how fast were the cars going when they smashed into each other? ; 3rd group not asked about vehicle speed.
a week later all ppts returned and were asked ‘did you see any broken glass?’ (there was none)
loftus and palmer secondary experiment results & explanation
verb used in original question affected whether the participants thought they saw broken glass. loftus and palmer therefore concluded that the leading question altered memory - substitution explanation
Loftus and Palmer (1974) evaluation
+ real world relevance, psychologist explains limitation of EWT in a court case
- artificial lab experiment so low ecological validity (less stressful than seeing a crime in real life)
evaluation of substitution explanation
- EWT is more accurate for some aspects than others. Sutherland and Hayne (2001) noticed that even for leading questions, recall of central events was more accurate than recall of small details. Substitution explanation did not predict that central memories would not be distorted by leading questions.
post event discussion
when co-witnesses of a crime discuss it together. this may influence the accuracy of witnesses’ recall of events
research on post event discussions - procedure
Fiona Gabbert et al (2003) used pairs of participants, each watched the same video of a crime but from a different point of view. Ppts discussed what they had seen before individually completing a recall test
Gabbert et al (2003) findings
71% of the pps mistakenly recalled details they did not recall but gained in discussion. Whereas the control group with no discussion had 0% recall of mistakes.
Gabbert et al (2003) conclusions
memory contamination -
co-witnesses discuss a crime and their memories become distorted as the combine (mis)information from other witnesses with their own memories
memory conformity-
witnesses go along with each other either to win social approval of because they believe the other witness is right and they are wrong (the actual memory is unchanged)
evaluation - evidence against memory conformity
post event discussion affects EWT. In a study, one clip showed a mugger’s hair to be light brown and another showed it to be dark brown. In pairs. ppts they discussed what they had seen, each having seen a different clips. After pps recalled it was said to be medium brown. Memory is distorted via communication in misleading PED, rather than memory conformity.
