Factors affecting the accuracy of eyewitness testimony Flashcards
what are the Factors affecting the accuracy of eyewitness testimony
misleading information, including leading questions and post-event discussion; anxiety
what is eyewitness testimony
Eyewitness testimony is when observers of events are asked to recall from memory details of what they have seen
What is Reconstructive memory
Reconstructive memory is memory that is not an accurate recording of events. It is reconstructed in recalling and may produce errors
What are leading questions
Leading questions are questions that imply a particular answer, and can influence how a memory is recalled. This could be due to an actual change in memory or due to the witness feeling emotional pressure to give a particular response. Memories could also be altered when recalled to be in line with a person’s pre-existing biases.
What are post event discussions
Post event discussion can also alter the memory, as one witness recalling events may alter the accuracy of the recall of another witness who heard their recall due to memory conformity, where witnesses go along with the accounts of others for social approval.
Study supporting leading questions
Loftus and Palmer (1974) aimed to investigate the effect of leading questions on the accuracy of eyewitness testimony.
Their sample consisted of 45 American students, who were divided into five groups of nine. All of the participants watched a video of a car crash and were then asked a specific question about the speed of the cars. Loftus and Palmer manipulated the verb used in the question, for example: “How fast were they cars going when they smashed / collided / bumped / hit / contacted with each other?’
They found that the estimated speed was affected by the verb used. The more extreme the verb, the faster the participants would estimate that the car had been going. For example, participants who were given the verb smashed reported an average speed of 40.5 mph, where participants who were given the word contacted reported an average speed of 31.8 mph, an overall difference of 8.7 mph.
The results clearly show that the accuracy of eyewitness testimony is affected by leading questions and that a single word in a question can significantly affect the accuracy of our judgements.
In a second experiment, Loftus and Palmer used a different sample of 150 American students, who were divided into three even groups. All the students watch a one-minute video depicting a car accident and were then given a questionnaire to complete.
One group was asked: “How fast were the cars going when they smashed into each other?”
Another group was asked: “How fast were the cars going when they hit each other?”
The final group (control) was not asked about the speed of the vehicles. One week later the participants were asked a series of questions via questionnaire about the accident. The critical question was: “Did you see any broken glass?” 32% of the participants who were previously questioned using the verb smashed, reported seeing broken glass; 14% of the participants who were previously questioned using the verb hit, reported seeing broken glass; and 12% of the control group reported seeing broken glass.
There was no broken glass in the video clip and the participants who were questioned previously using the verb smashed, were significantly more likely to report seeing the broken glass, as a result of the earlier leading question. The verb smashed has connotation of faster speeds and broken glass and this question led the participants to report seeing something that was not actually present. Their memory for the original event was distorted by the question used (response substitution) one week earlier. In conclusion this study demonstrates the power of leading questions, and implies that they can potentially have a longer term impact on accuracy of recall of the incident.
Loftus and palmer evaluation
•Loftus and Palmer’s research has questionable ecological validity. On the one hand, questioning participants about everyday events like a car crash appears to be a genuine measure of eyewitness testimony. However, the participants in their research watched a video of a car crash and witnessed the events unfold from start to finish. In everyday reports of car accidents, witnesses rarely see the whole event; they are either involved in the event directly, or see a small part of the event happen in their peripheral vision. Therefore, their results to do reflect everyday car accidents and we are unable to conclude if participants involved in real accidents, who would have a stronger emotional connection to the event, would also be susceptible to leading questions in the same way.
•A second weakness of Loftus and Palmer’s research is that their study lacks population validity. Their two experiments consisted of 45 and 150 American students. It is reasonable to argue that the students in their experiment were less experienced drivers, who may be less accurate at estimating speeds. Consequently, we are unable to generalise the results to other populations, for example, older and more experienced drivers may be more accurate in their judgement of speeds and therefore not as susceptible to leading questions.
Evaluations for post event discussion
•Gabbert (2003) videos of crimes shot from different perspectives were used. A different video was shown to each participant in pairs of participants, with unique information available in each film. In one condition the pairs were allowed to discuss what they had seen, and in another they weren’t. 71% of pairs allowed to discuss what they had seen included aspects of the film they had not seen in their recollection of the video. This compared to 0% in pairs who were not allowed to discuss what they had seen. This suggests that witnesses will change their accounts of crimes to match what other witnesses have said. This may be an attempt to seek social approval, resulting in memory conformity.
•However, this was a laboratory situation unlike real life (low ecological validity), and there were no consequences to participants for adapting their memories (low mundane realism as there would be in real life), so memory conformity may not be as common in real life.
What is anxiety
Anxiety is a mental state of arousal that includes feelings of extreme concern and tension. This often accompanies physiological changes such as increased heart rate.
How anxiety effects eyewitness testimony
Eyewitness testimony is often used after violent crimes that have caused eyewitnesses high anxiety. Research on eyewitness testimony often has no emotional impact on the participant, resulting in low validity. So research that does not cause anxiety cannot be generalised to the courtroom as the participants don’t have the same mental state as the eyewitnesses.
Research indicates that high levels of anxiety produces poor recall of the perpetrator. However, this may be due to Weapon focus. Weapons are a cause of anxiety, so witnesses may be distracted by them, thus focusing their attention on the weapon rather than the criminal.
However, some anxiety may increase recall as it is a state of arousal so could improve general alertness/awareness of the situation and surroundings. The emotional aspect could also improve memory encoding.
The Yerkes- Dodson Law of arousal states that these conflicting results could be explained by accuracy increasing as anxiety raises eyewitness accuracy up until a point where anxiety becomes too high and more stress results in lower accuracy.
Research on anxiety and eyewitness testimony
•Loftus (1979) placed participants outside a lab so that they could listen to conversations. In one condition it was a normal conversation about equipment failure, and a man walks out with greasy hands and a pen. In another condition the conversation is hostile and there would be the sound of breaking glass and furniture being knocked over. A man walks out with a knife covered in blood. Participants were then given 50 photographs and asked to identify the man who came out of the lab. Found more identified the man with the pen (49%) than the man with the knife (33%). This suggests that the high anxiety caused by the knife took focus away from the face, so this study acts as evidence for weapon focus.
•Peters (1988) found that participants who visited a healthcare centre and interacted with a researcher and a nurse were more able to recognise the researcher than the nurse because the nurse gave them an injection, suggesting that there was weapon focus on the needle. This is better as it has high ecological validity (normal setting) and high mundane realism (getting an injection is a normal procedure) so its results are more generalisable.
•Yuille and Cutshall (1986) interviewed 13 witnesses of a real shooting in Canada four months later. Despite leading questions recall was as high as 88%, and those who reported the highest levels of stress at the time gave the most accurate responses. This suggests that in real life situations anxiety many not have the same effect on witnesses as participants in a lab, making them more accurate, not less.
Evaluation of eyewitness testimony research
•There is research that suggests that individual factors such as personality and age can influence the impact of misleading information. For example, Warren et al (2005) found that misleading information such as leading questions are more effective on children than adults, which has implications for how children are treated as witnesses.
•As studies such as Loftus’s use films of staged crashes and crimes, and are conducted in a laboratory setting rather than in a courtroom there is lack of consequence for inaccurate eyewitness testimony. Also lab based studies suffer from demand characteristics as participants want to ‘help’ the researcher by giving them the responses that they expect.
•Loftus’ (1979) study can be seen as unethical as it was designed to create high levels of anxiety, so this goes against the psychologist’s duty to protect participants from (in this case mental) harm.
