factors affecting accuracy of EWT: misleading info Flashcards
what is an eyewitness testimony?
when people remember the details of events (eg. accidents, crimes) which they have observed themselves
what factors can the accuracy of EWT affected by?
- misleading information
- anxiety
what is the procedure for research on leading questions? (loftus and palmer 1974)
- 45 students watched film clips of car accidents
- asked them questions about the accident
- in the critical question, ps were asked to describe how fast the cars were travelling: ‘about how fast were the cars going when they hit each other?’
- 5 groups of ps, each group had a different word in the critical question: hit, contacted, bumped, collided or smashed
what were the findings for loftus and palmer’s research on leading questions?
- mean estimated speed was calculated for each group
- ‘contacted’ - mean estimated speed was 31.8 mph
- ‘smashed’ - mean estimated speed was 40.5 mph
- therefore, leading questions biased the eyewitness’s recall of the event
what are 2 explanations for as to why leading questions affect EWT?
- response-bias explanantion
- substitution explanation
what is the response-bias explanation?
- wording of question has no real effect on ps’ memories, but influences how they decide to answer
- when a p has a leading question with the word ‘smashed’, it encourages them to choose a higher speed estimate
what is the substitution explanation?
wording of a leading question changes p’s memory of the event
what support is there for the substitution explanation? (loftus and palmer 1974)
- ps who originally heard ‘smashed’ were later more likely to report seeing broken glass, when there was none, vs. ps who heard ‘hit’
- critical verb altered memory of incident
what is a post-event discussion?
- occurs when there is more than one witness to an event
- witnesses may discuss what they have seen with co-witnesses or other people
- this may influence the accuracy of each witness’s recall of the event
what is the procedure for research on post-event discussion? (gabbert et al. 2003)
- studied participants in pairs
- each participant watched a video of the same crime, but filmed from different points of view
- this meant that each participant could see elements in the event that the other could not
- both participants then discussed what they had seen before individually completing a test of recall
what were the findings of gabbert et al.’s research on post-event discussion?
- 71% of participants mistakenly recalled aspects of the event that they did not see in the video, but had picked up in the discussion
- in the control group where there was no discussion, there was 0% mistaken recall
- this was evidence of memory conformity
what were the 2 explanations for as to why post-event discussions affect EWT?
- memory contamination
- memory conformity
what is memory contamination?
when co-witnesses to a crime discuss it with each other, the EWT may become altered or distorted
why might memory contamination happen?
co-witnesses combine (mis)information from other witnesses with their own memories, so the actual memory changes
what is memory conformity?
when witnesses go along with each other, so their actual memory is unchanged (gabbert et al.)
why might memory conformity happen?
- to win social approval
- genuinely believe other witnesses are right and they are wrong
evaluation: real-world application in criminal justice system
- consequences of inaccurate EWT can be very serious
- psychologists are sometimes asked to act as expert witnesses in court trials and explain the limits of EWT to juries
- psychologists can help improve the legal system, especially by protecting innocent people from faulty convictions based on unreliable EWT
evaluation: RWA research support (loftus 1975)
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
evaluation: practical applications of EWT may be affected by issues with research (foster et al. 1994)
- what eyewitnesses remember has important consequences in the real world, but ps’ responses in research don’t matter in the same way, so less motivated to be accurate
- L&P’s ps watched film clips in a lab, which is a very different experience from witnessing a real event (eg. less stressful)
- researchers (eg. loftus) are too pessimistic about the effects of misleading information; EWT dependable than many studies suggest
evaluation: false memory (cliasefi et al. 2013)
- attempted to use leading qs to plant a memory of an event that never happened
- gave ps a document claiming to be a personalised food and drink profile put together by a computer based on their earlier responses to a questionnaire
- in 1 group, their profiles contained the false information that they had once drunk so much alcohol they were sick
- later, the pps completed a memory test in which a leading question asked when they had become sick from drinking too much alcholol
- a significant number of the pps ‘recalled’ being sick due to drinking too much alchool when they were younger
- some of these pps also claimed that they now disliked certain alcoholic drinks because of this (non-existent) experience
evaluation: evidence against substitution (sutherland and hayne 2001)
- showed ps a video clip
- when asked misleading questions later, recall was more accurate for central details of event > peripheral ones
- ps’ attention was focused on central details so these memories were resistant to misleading info
- original memories for central details survived and were not distorted
- not predicted by substitution explanantion
- EWT more accurate for some aspects of an event than for others
evaluation: evidence that PED actually alters EWT, challenging memory conformity (skagerberg and wright 2008)
- showed ps film clips
- 2 versions eg. a mugger’s hair dark brown in one but light brown in other
- ps discussed the clips in pairs, each having seen different versions
- didn’t report what they had seen, what they had heard from the co-witness, but a blend of the two
> common answer to the hair question was not ‘light brown’ or ‘dark brown’ but ‘medium brown’ - therefore, memory itself is distorted through contamination by misleading PED, rather than the result of memory conformity
evaluation: disentangling PED (bodner et al. 2009)
- effects of PED can be reduced if ps are warned of their impact
- recall was more accurate for ps who were warned that anything they hear from a co-witness is second-hand information and that they should forget it and recall only their own memory of the event
evaluation: demand characteristics (zaragoza and mccloseky 1989)
- argue that many answers given by ps in lab studies are due to demand characteristics
- ps usually want to be helpful and not let the resarcher down so they guess when they are asked a question they don’t know the answer to
