factors effecting the accuracy of eyewitness testimony Flashcards
what is research on leading questions (misleading info)
wording of question may lead or mislead to give certain answer
eyewitness testimony-police questions may direct witness ti give particular answer
loftus and palmer- 45 pps t watch film clips of car accidents and asked them questions about accident- asked to describe how fast the cars were travelling, five groups of pps and each group given differnt verb in critical question- hit, contacted, bumped, collided smashed
mean estimated speed calculated for each pps group
contacted- mean estimated speed of 31.8mph
smashed- 40.5mph
biased eyewitness recall of event
what is why do leading questions affect ewt (misleading info)
response bias explanation suggests wording of question has no real effect in pps memories but influences how they decide to answer
when pps get leading question using word smashed, encourages them to choose hgiher speed estimate
loftus and palmer- second experiement support substitution expkanation whcih proposes wording of leading question changes pps memory of film clip, shown becayse pps originally heard smashed more likely report seeing boroken glass when there was none than those who heard hit, critical verb altered memory of incident
what is research on post event discussion (misleading info)
gabbert-studied pps in pairs, each pps watched video of same crime but dilmed from different points of view, each pps could see elements in video the other couldnt, both pps discussed what they had seen before indvidiually completing test of recall
researchers found 71% ppps mistakenly recalled aspects of event that they didnt see in video but picked up in discussion, corresponding figure in control group where no discussion was 0%, evidence of memory conformity
what is why does post event discussion affect ewt (misleading info)
memory contamination- co witness to crime discuss it with each other, their ewt may become altered or distorted
they combine misinformation from other witnesses with their own memories
memory conformity- witnesses go along with each other to win social approval or because they believe the other witnesses are right and they are wrong
actual memory is unchanged
what is real world application (misleading info eval)
important practical uses in criminal justice system
consequences of inaccurate ewt serious
loftus- leading questions can have distortin geffect on memory that police officers need to be careful about how they phrase questions when interviewing ews
psychologists sometimes asked to act as expert witness in court trials and explain limits of ewt to juries
shows psychologists can help to improve the way the legal system works- protect innocent people from faulty convictions based on unreliable ewt
practical applciations of ewt may be affected by issues with research
pps watched film clips in lab- different experience from witnessing real event
foster- what ews remember has important consequences in real world but pps responses in research dont matter in same way
suggests researchers are too pessimistic about effects of misleading info- ewt more dependent than many studies suggest
what is evdence against substitution (misleading info eval_
ewt more accurate fro some aspects of event than for others
sutherland and hayne- showed pps video clip when pps asked later misleading questions recall was more accurate for central details of event than peripheral ones, pps attention focused on central features of event and memories were relatively resistant to misleading info
suggests original memories for central details survived and were not distorted- outcome not predicted by substitution explanation
what is evidence challenging memory conformity (misleading info eval)
evidence that post event discussion alters ewt
skagerberg and wright- showed pps film clips, two versions- muggers hair dark brown in one but light brown in other, pps discussed clips in pairs, did not report what they had seen in clips or what heard from cowitness but blend of two
memory distorted through contamination by misleading post event discussion rather than result of memory conformity
what is anxiety has a negative effect on recall (weapon focus) (anxiety)
creates phsyiological arousal in the boyd why prevents us paying attention ti important cues so recall worse
ewt- look at effect of presence of weapon which creates anxiety, leads to focus on weapon reducing witnesses recall for other details of event
johnson and scott-pps believed taking part in lab study, seated in waiting room pps in low anxietty condition heard casual conversation in next room and saw man walk past them carrying pen with grease on hands, others heard heated argument accompanied by sound of breaking glass, man walked out of room holding knife covered in blood- high anxiety condition
pps later pickd out man from set of 50pics 49% seen man carrying pen able to identify him, corresponding figure for those in high anxiety was 33%
tunnel theory of memory-people have enhanced memory for central events, weapon focus can have this effect
what is anxiety has positive effect on recall (anxiety)
fight or flight response triggered increasing altertness- may imrpvoe memory for event as become more aware of cues in situation
yuille and cutshall-actual shooting in gun shop vancouver- shop owner shot thief dead, 21 witnesses, 13 took part in study, interviewd four to five months after incident and these itnerviews compared with original police interviews at time of shooting, accuracy determined by number of details reported in each account, witnesses asked to rate how stressed they felt at the time and wehrther they had ant emtoional problems since
witnesses accurate and little change in amount recalled or accuracy after five months, some less accurate such as colour of items age height weight estimates, pps reported highlest levelsof stress most accurate 88% compared to 75% for less stressed group
anxiety does not hace detrimental effect on accuracy of ew memory in real world context and may even enhance it
what is explaining contradictory findings (anxiety)
yerkes and dodson-relationship between emtional arousal and performances looks like inverted u
deffenbacher- reviweed 21 studies of ewt and noted contradictory findings on effects anxiety
yerkes dodson law-when witness crime become emotionally and physiologicall aroused, experience anxiery as well as physiological changes in body, lower levels of anxiety or arousal produce lower levels of recall accuracy and memory becomes more accurate as level of anxiety increases
optimal level of anxiety, point of max accuracy, if person experiences more arousal then their recall suffers drastic decline
what is unusualness not anxiety (anxiety eval)
johnson and soctt-may not have tested ancxiety
pps focused on weapon may be because they were surprised at what they saw rather than scared
pickel-condcted experiment using scissors hangun wallet or raw chicken as hand held items in hairdressing salon video
ew accuracy signf poorer in high unusalness conditions
suggests weapon focus effect due to unusualness rather than anxiety or threat and tells us nothing specifically about effects of anxiety on ewt
what is support for negative effects (anxiety eval)
evidence supporting view anxiety has negative effect on accuracy of recall
valentine and mesout- supports research on weapon focus finding negative effects on recall, researchers used objective measure to divide pps in high and low anxiety groups, anxiety disrupted the pps ability to recall details about actor in london dungeons lanrybth
high level of anxiety does have negative effect on immediate eyewitness recall of stressful event
what is support for positive effects (anxiety eval)
evidence showing anxiety can have positive effects on accuracy of recall
christianson and hubinette interviewd 58 witnesses to actual bamk robberies in sweden
some witnesses directly involved and some indirectly involved
researchers assumed that those directly involved would experience the most anxiety
found that recall was more than 75% accurate across all witnesses
direct victims were even more accurate
actual crimes confirm anxiety does not reduce accuracy of recall for ew and may even enhance it
christianson and hubinette interviewed their pps several months after the event
researchers had no control over what happened to their pps in the intervening time
effects on anxiety may have been overwhelmed by these other factors and impossible to assess by the time the pps were interviewed
possible that lack of control over confounding varuables may be responsible for these findings invalidating their support
