FACTORS AFFECTING EYE WITNESS TESTIMONY Flashcards
EYE WITNESS TESTIMONY
legal term to describe the evidence provided in court by a person who was present at the time a crime took place.
factors affecting eye witness testimony
- misleading information ( leading questions and post event discussion
- anxiety.
misleading information
incorrect information given to the eye witness usually after the event has taken place. Barlett argued that memories are not accurate snapshots of events but are reconstructions. schemas are mental shortcuts and the recall of memories is highly influenced by schemas.
leading questions
questions that imply a particular answer can influene how a memory is recalled. this could be due to an actual change to the memory ( substitutional bias explanation) or not to a change in memory but due to an emotional pressure to give a particular response ( response bias explanation)
post event discussion
post event discussion is when two witnesses have a conversation after a crime takes place which may contaminate a witness memory for the event.
research into the effects of the leading questions
Loftus and Palmer. 45 participants were shown clips of traffic accidents. after watching the clips they were asked the following critical ( leading) questions. how fast were the cars going when they __ into each other? the missing verb was changed into smashed, collided, bumped, hit, contracted. it was found that the more extreme the verb, the more faster the estimation of the MPH. contacted - 31.8 and smashed - 40.8.
This suggests that misleading information in the form of leading questions can influemce the recall of the eye witness testimony.
extended study by loftus and palmer
after one week the participants were invited again. 150 participants were shown a car accident clip without a broken glass. after viewing they were asked how far the car was going including verb either hit or smashed or a control group. after one week participants completed a questionnarie, did you see a broken glass? it was found that participants were twice as likely to respond yes in smashed condition rather than the hit condition. this suggests the effect of misleading information in the form of leading questions can be long lasting and actually changes memories via substitution rather than response bias.
research into post event discussion by gabbert.
Participants watched a video of a girl stealing money from a wallet. The participants were either tested individually (control group) or in pairs (co-witness group). The participants in the co-witness group were told that they had watched the same video, however they had in fact seen different perspectives of the same crime and only one person had actually witnessed the girl stealing. Participants in the co-witness group discussed the crime together. All of the participants then completed a questionnaire, testing their memory of the event.
Gabbert et al. found that 71% of the witnesses in the co-witness group recalled information they had not actually seen and 60% said that the girl was guilty, despite the fact they had not seen her commit a crime. These results highlight the issue of post-even discussion and the powerful effect this can have on the accuracy of eyewitness testimony.
anxiety
anxiety is a mental state of arousal that includes feeling of extreme tension and concern.
anxiety and the weapon focus effect
the presence of a weapon increases anxiety. this makes the eye witness focus on central details i.e the weapon rather than the peripheral details. this means that the eye witness may struggle to recall key details of what they saw. they are so focused on the weapon making the eye witness testimony inaccurate.
Yerks Dodson law of arousal
this theory states that eye witness testimony accuracy increases as the anxiety increases as the witness becomes alert upto an optimal point. however at a point anxiety becomes too high and more distress or stress results in lower accuracy.
research into the effect of anxiety on the eye witness testimony
Johnson and Scott
they conducted a lab experiment where participants were split into two conditions and instructed to wait outside the room before the study began. in both conditions participants heard a discussion in the neighbouring room. in condition 1 , a man came out holding a pen and with grease on his hands. in conditin 2, the discussion was more heated and a man emerged holding a paper knife covered in blood. the participants were later asked to identify man from 50 photographs. it was found that participants in condition 1 ( pen and grease were 49% accurate and participants in condition 2( paper knife and blood) were only 33% accurate. it can be concluded that anxiety caused by the weapon narrowed focus of attention making recall les detailed and accurate.
