4.1.2 Eye Witness Testimony - misleading information Flashcards
Research on leading questions - experimenter
Crime incident
LOFTUS AND PALMER
1974
Research on leading questions - procedure
LOFTUS AND PALMER
45 student participants watched clips of 7 different car accidents and then were asked leading questions about them.
In the critical question (leading question or misleading information) the participants were asked to describe how fast the cars were going.
There were 5 different groups of participants and 5 different verbs were used to describe speed varying in severity (contacted, hit, bumped, collided + smashed)
Research on leading questions - results
LOFTUS AND PALMER
As the verb ‘smashed’ has connotations with increased speed, this group estimated the speed as higher than the other groups. This shows that misleading or suggestive information can distort Eye Witness Memory.
Research on leading questions - findings
LOFTUS AND PALMER
The mean estimated speed was calculated for all 5 groups. The verb ‘contacted’ (the least severe) gave the average speed of 31.8 mph, whereas the verb ‘smashed’ (the most severe) gave an average speed of 40.5mph.
This showed that the leading question, in this case the severity of the verb used, biased the eyewitness’s recall of the event.
How do leading questions affect EWT?
The ‘response-bias’ explanation suggests that the wording of the question has no real effect on the participants’ memories, but just influences how they describe the answer.
LOFTUS AND PALMER (1974) conducted a second experiment that supported the substitution explanation, which proposes that the wording of a leading question changes the participant’s memory of a film clip.
Experiment two
LOFTUS AND PALMER
150 student participants were shown a short film that showed a multi-vehicle car accident and they were asked questions about it. The participants were split into 3 groups (with 50 in each group).
1st group – ‘how fast were the cars going when they hit each other?’
2nd group – ‘how fast were the cars going when they smashed into each other?’
3rd group – asked nothing about the speed
All groups returned a week later and were asked:
“Did you see any broken glass?” even though there was none in the film.
Experiment two - results
Response Smashed Hit Control
Yes 16 7 6
No 34 43 44
Research on leading questions - result
LOFTUS AND PALMER
Contacted - 31.8 mph
Hit - 34.0 mph
Bumped - 38.1 mph
Collided - 39.3 mph
Smashed - 40.8 mph
Research on post-event discussion - experimenter
Eyewitnesses to a crime may sometimes discuss their experience and memories with each other.
Fiona Gabbert et. Al (2003) looked at post-event discussion (PED)
Research on post-event discussion - procedure
Fiona Gabbert et. al (20003)
Studied participants in pairs
Each participant watched a video of the same crime but filmed from different points of view
Each participant could see something the other could not
Both participants then discussed what they had seen before individually completing a test of recall
Research on post-event discussion - findings
Fiona Gabbert et. al (2003)
71% of participants mistakenly recalled aspects of the event that they did not see in the video but had picked up in the discussion
They also completed this study with a control group where NO discussion occurred. In this experiment there was 0%
This was evidence of memory conformity
Why does post-event discussion affect EWT? - explanation one
Memory contamination
When co-witnesses to a crime discuss it with others, their testimonies become altered or distorted
This is because they combine (mis)information from other witnesses with their own memories
Why does post-event discussion affect EWT? - explanation two
Memory conformity
Gabbert et al. concluded that witnesses often go along with each other, either to win social approval or because they believe the other witnesses are right and they are wrong. Unlike with memory contamination, the actual memory is unchanged
Research on post-event discussion evaluation - real world applications
Important practical uses in the criminal justice system – the consequence of inaccurate EWT can be very serious
Loftus (1975) believes that leading questions can have such a distorting effect on memory that police officers need to be extremely careful about how they phrase their questions when interviewing eyewitnesses
Psychologists are sometimes asked to act as expert witnesses in court trials and explain the limits on EWT to the juries
Research on post-event discussion evaluation - real world application counterpoint
The practical applications of EWT may be affected by issues with research
Loftus and Palmer’s research was carried out in a lab – the participants watched the crashes on a screen
This is a very different experience to real life and a lot less stressful
Rachel Foster et. Al (1994) stated that what an eyewitness remembers in real-life can have important consequences. However, responses given in a lab situation are less important so participants may be less motivated to be accurate
This suggests that the research by Loftus and Palmer is too pessimistic about the effects of misleading information – EWT may be more trustworthy and reliable that many studies suggest
Research on post-event discussion evaluation - evidence against substitution
- One limitation of the substitution explanation is that EWT is more accurate for some aspects of an event than for others
- Rachel Sunderland and Harlene Hayne (2001) showed participants a video clip
- When participants were later asked misleading questions – recall was more accurate for central details rather than the peripheral ones
- The participants attention was focussed on the central focus and these memories were relatively resistant to misleading information
- This suggests that the original memories for central details survived and were not distorted, an outcome that is not predicted by the substitution explanation
Research on post-event discussion evaluation - evidence challenging memory conformity
Evidence challenging memory conformity:
* Another limitation of the memory conformity explanation – evidence that post-event discussions actually alters EWT
* Elin Skagerberg and Daniel Wright (2008) showed their participants film clips. There were two different versions e.g. 1st clip the mugger had dark brown hair and the 2nd clip the mugger had light brown hair
* Participants discussed the clips in pairs – each having seen the two versions
* They did not report what they had seen or what they had discussed between themselves but instead a ‘blend’ between the two
* This suggests that the memory itself is distorted through contamination by misleading post-event discussion
Research on post-event discussion evaluation - demand characteristics
Demand characteristics:
* Lab studies have identified misleading information as a cause of inaccurate EWT
* Maria Zaragoza and Michael McCloskey (1989) argued that many answers given by participants in lab studies are due to demand characteristics
* Participants want to be helpful and not let the researcher down so they guess when they are asked a question that they don’t know the answer to
Anxiety - weapon focus
Anxiety has a negative effect in recall (weapon focus):
* Psychological arousal in the body prevents us from paying attention to important cues – recall is worse.
* Looking at the effect of anxiety and EWT when a weapon is present.
* The weapon creates anxiety which reduces the witness’s recall of the event.
Anxiety weapon focus study - procedure
Craig Johnson and William Scott (1976)
Procedure: The participants believed they were taking part in a lab experiment and were seated in the waiting room.
There were two different groups:
* High anxiety condition – overheard a heated argument, smashed glass and then a man walking out of the room with a knife covered in blood
* Low anxiety condition – overhead a casual conversation and then a man walking out of the room carrying a pen with grease on his hands
Anxiety weapon focus study - findings and conclusion
Craig Johnson and William Scott (1976)
Findings and conclusions: The participants were then shown 50 photos and they had to correctly pick out the man they had seen
49% who had seen the man carrying a pen were able to identify him
33% were able to identify the man with the knife/blood
The tunnel theory of memory argues that people have enhanced memory for central events – weapon focus as a result of anxiety can have this effect
Weapon focus evaluation
- Unusualness NOT anxiety
- One limitation of Johnson and Scott’s study (knife/pen) is that it may NOT have test anxiety
- Focussing on the object being carried may have been surprised rather than being scared
Weapon focus evaluation - study
Kerry Pickel (1998)
conducted an experiment in a hairdressers using the following four items – a handgun, a wallet, scissors and raw chicken.
High anxiety, low unusualness = scissors
High unusualness = chicken/handgun
Eyewitness accuracy was significantly poorer in the high unusualness conditions – chicken and handgun
This suggests that the weapon focus effect is due to unusualness rather than anxiety
Weapon focus evaluation - support for negative effects
- Tim Valentine and Jan Mesout (2009) supports the research on weapon focus – negative effects on recall
- They used an objective measure (heart rate) to divide participants into high and low anxiety level groups
- In the study, anxiety disrupted the participants’ ability to recall details about the actor in the London Dungeon
- Therefore, high levels of anxiety do have a negative effect on the immediate eyewitness recall of a stressful event
Anxiety has a positive effect on recall
- Witnessing a stressful event creates anxiety through psychological arousal within the body
- Fight or flight is triggered – this may improve memory as we become aware of cues in the situation
Anxiety has a positive effect on recall
John Yuille and Judith Cutshall (1986)
Procedure:
* Study of an actual shooting in a gun shop in Vancouver, Canada.
* The shop owner shot the thief dead.
* 21 witnesses – 13 took part in the study
* They were interviewed 4/5 months after the event and these interviews were compared to the original police interviews
* Accuracy measured – number of details reported in each account
* Had to rate how stressful the incident was (7 point scale) and whether they had emotional problems (sleeplessness)
Findings and conclusions:
* Witnesses were very accurate and very little changed in recall – some details were less accurate (colours, age, height, weight)
* Those who reported the highest levels of stress were most accurate.
* This suggested that anxiety does not have a detrimental effect on the accuracy of eyewitness memory and may even enhance it
Support for positive effects
- Sven-Ake Christianson and Birgitta Hubinette (1993)
- Interviewed 58 witnesses to actual bank robberies in Sweden
- Some witnesses were directly involved (e.g. bank worker) and others were indirectly involved (e.g. bystander)
- The researchers assumed (hypothesised) that those directly involved would experience the most anxiety
- It was found that recall was more than 75% accurate across all witnesses
- The direct victims (experiencing higher anxiety) were even more accurate
- These findings from actual crimes show that anxiety does not reduce the accuracy of recall and may even enhance it
Positive effects counterpoint
- Christianson and Hubinette interviewed their participants several months after the event had taken place – between 4-15 months
- The researchers had no control over the participants in this time – post-event discussion/news reports
- Therefore, the effects of anxiety may have been overwhelmed by other factors and impossible to accurately assess
- Therefore, it is possible that a lack of control over confounding variables may be responsible for the findings, invalidating the research
Explaining the contradictory findings
Yerkes and Dobson – inverted u theory of arousal
Yerkes and Dobson (1908) looked at the relationship between emotional arousal and performance
Deffenbacher (1983) reviewed 21 studies of EWT and notified contradictory findings of the effects of anxiety
He used Yerkes and Dobson’s law to explain this
When you witness a crime/accident you become emotionally and physically aroused
Lower levels of arousal/anxiety produce lower levels of recall accuracy
Memory becomes more accurate as the level of arousal/anxiety increases
There is an optimum level of arousal/anxiety where there is maximum accuracy – over this level, recall suffers drastically
