1/20
Looks like no tags are added yet.
Name | Mastery | Learn | Test | Matching | Spaced |
---|
No study sessions yet.
factors affecting the accuracy of EWT
misleading information
-leading questions: police may direct a witness to give a particular answer through question wording, which usually arises with eye witness testimonies.
-procedure- elizabeth loftus and john palmer (1974) arranged 45 student participants to watch car crash film clips and then questioned them on what they had seen. the wording of the questions was manipulated; for example, some participants were asked how fast the cars were going when they "smashed" into each other, while others were asked the same question using the word "hit." this subtle change in wording significantly affected the participants' speed estimates, demonstrating how easily memory can be influenced by external factors.
findings
findings- the mean estimate speed for ‘contacted’ was 31.8mph, however for the verb 'smashed,' the mean estimate was significantly higher at 40.5 mph, illustrating the impact of language on memory recall. this shows the leading question biased the eyewitness’ event recall.
why do leading questions affect EWT
-response-bias explanation suggests that the wording has no real effect on participants’ memories, but just influences how they decide to answer their recollections. this implies that witnesses may adjust their memories to align with the expectations set by the phrasing of questions, ultimately leading to inaccuracies in their testimonies. (‘smashed’ encourages them to choose a higher speed estimate while a neutral term like 'hit' would likely result in a more conservative estimate, demonstrating how subtle variations in language can shape a witness's perception of an event).
research on post-event discussion
procedure- fiona gabbet et al (2003) studied participants in pairs. each watched a video of the same crime filmed from different povs, meaning one could see elements in the event that the other could not. both then discussed what they had seen before individually completing a recall test
findings- 71% of participants mistakenly recalled aspects of the events of the event that they did not see in the video but had picked up in the discussion. those in a control group with no discussion was 0% therefore showing evidence of memory conformity (NSI), and memory contamination (when eyewitnesses combine (mis)information from other witnesses)
why does post-event discussion affects EWT?
-memory contamination: when co-witnesses to a crime discuss their recollection of events with eachother, their EWT become altered or distorted due to them combining (mis)information from other witnesses to their own memory.
-memory conformity: where witnesses alter their memories to match others due to ISI or NSI, further complicating EWT. unlike memory contamination, the actual memory is unchanged.
evaluation of factors affecting accuracy of EWT (misleading information)
strengths
-high external validity: research has important practical uses in the criminal justice system - loftus (1975) showed leading questions can affect memory and aided development of the cognitive interview, improving the legal system and protecting the innocent of faulty convictions
counterpoint: loftus and palmers p’s watched film clips in a lab - very different from witnessing a real event (less stressful). rachel foster et al. (1994) states that what EW remember has real world implications but p’s responses don’t matter in the same way (less motivated to be accurate), suggesting researchers are too pessimistic, and that EWT may be more dependable than suggested.
evaluation of factors affecting accuracy of EWT (misleading information)
limitations
-evidence against substitution: rachel sutherland and harlene hayne (2001) showed participants a video and later questioned with misleading questions. recall was more accurate for central details than for peripheral ones - presumably because p’s attention was more focused on central details so the memories were more resistant to misleading info ∴ an outcome not predicted by the substitution explanation.
-evidence that post-event discussion actually alters EWT: elin skagerberg and daniel wright (2008) showed partnered p’s two variant film clips (difference was hair colour). the findings were often a blend, not just one p’s answer, suggesting memory contamination is more prominent than memory conformity.
factors affecting EWT accuracy (anxiety)
negative affect on recall (weapon focus)
-anxiety affects psychological arousal, preventing us paying attention to important cues, so recall is worse
procedure: craig johnson and william scott (1976) p’s were seated in a waiting room, in the low-anxiety condition, and heard a casual conversation in the next room, then saw a man walk past carrying a pen with grease on his hands.
other participants heard a heated argument, accompanied by the sound of breaking glass. a man walked out the room holding a blood covered knife; the high-anxiety condition.
findings
the participants later picked out the man from a set of 50 photos, 49% who had seen the pen-carrying man were able to identify him, however the figure was 33% wet able to identify the man holding the blood-covered knife.
tunnel theory of memory: people have enhanced memory for central events; weapon focus as a result of anxiety can have this effect.
anxiety having a positive effect on recall
-the fight or flight response, triggered by the physiological arousal the body may improve memory for the event as we can become more aware of cues.
procedure: john yullie and judith cutshall (1986) conducted a study of an actual shooting in a bodega. 13/21 witnesses took part in the study five months post-incident. accuracy was determined by the number of details reported in each account, and asked to rank their fear on a scale and whether they had had emotional problems since.
findings and conclusions
-witness were very accurate in their accounts, there was little change in the amount recalled; the p’s who reported highest stress levels were most accurate, suggesting anxiety doesn’t have a detrimental effect on accuracy of eyewitness memory in a real world context, and could even enhance it.
evaluation of factors affecting EWT accuracy (anxiety)
strengths
-countering evidence that anxiety has a negative effect on the accuracy of recall. tim valentine and jan mesout (2009) supports the research on weapon focus, finding negative effects on recall. the researchers used an objective measure (heart rate) to divide p’s into high and low anxiety groups; where the was a significant difference. suggests anxiety has a negative effect on the immediate EWT of a stressful event.
-evidence suggesting positive effects: sven-ake christianson and birgitta hubinette (1993) interviews 58 witnesses to actual robberies; workers and bystanders. the direct witnesses (workers) had more accurate recall than bystanders. suggests, from findings from actual crimes, anxiety doesn’t reduce accuracy of recall for EWT
evaluation of factors affecting EWT accuracy (anxiety)
limitations
study johnson and scott may not have tested anxiety; reason for p’s focusing on weapon could have been due to surprise rather than fear. kerri pickel (1998) conducted an experiment using scissors, a handgun and a wallet or a raw chicken as the handheld item in a hairdressing salon video. EWT was significantly poorer in high unusualness conditions, suggesting weapon focus effect is due to unusualness rather than anxiety/ threat and tells us nothing about the effects of anxiety on EWT
improving the accuracy of EWT - cognitive interview
-developed by ronald fisher and edward geiselman (1992) argued EWT could be improved if police used better interviewing techniques based on psychological insights.
4 main techniques used:
report everything
reinstate the conext
reverse the order
change perspective
1- report everything
-encourage witness to include every detail of the event although it may seem irrelevant and the witness doesn’t feel confident about the information or accuracy.
-done as seemingly trivial details may be important and may trigger other important memories
2- reinstate the context
-witness should return to original crime scene in their mind and imagine the environment (weather, sight, senses) and their emotions at the time
-related to context-dependant forgetting
3- reverse the order
-events should. be recalled in a different order from original sequence, out of chronological order
-done to prevent people reporting their expectations of how events must have happened rather than reporting the actual events + prevents dishonest accounts (harder to produce an untruthful account reversed)
4- change perspective
-witnesses should recall the incident from the perspective of others. (eg of other witnesses, victim or perpetrators)
-done to disrupt expectations and disrupt the effect of schema on recall (contrast between what would have happened vs what actually happened
enhanced congnituve interview (ECI)
fisher et al. (1987) developed additional elements of the CI to focus on the social dynamic of the interaction (eg interviewer needs to know when to establish eye contact and when to relinquish it)
-ECI also includes ideas such as reducing eye witness anxiety, minimising distractions, getting the witness to speak slowly and asking open-ended questions
evaluation of improving accuracy of EWT - cognitive interview
strengths
-evidence that it works: meta-analysis by gunter kohnken et al. (1999), combined data from 55 CI and ECI comparison studies with a standard police interview. the CI gave 41% increase in accurate information, showing CI is effective to recall memory information that is available but not immediately accessible
counterpoint: kohken et al found increase in amount of inaccurate information recalled by p’s (more with ECI). they may sacrifice EWT quality in favour of quantity, so officers should treat eyewitness evidence with caution.
evaluation of improving accuracy of EWT - cognitive interview
limitations
-not all elements are equally effective or useful. milne and bull (2002) found each four techniques used alone produced more information but using a combination of first two steps produces better recall than any other combination ∴ casting doubt in overall credibility of CI
-police officers may be reluctant to useCI as it’s more time consuming and requires more training. (eg more time needed to establish rapport with eye witnesses and allow them to relax) many forces don’t have the resources for this (kebbell and wagstaff 1997) - suggests it’s not a realistic method.