Memory: EWT Flashcards
What is Eyewitness testimony?
the evidence provided in court (and a police station) by a person who witnessed a crime, with a view to identifying the perpetrator.
They use their memory of the crime to give their testimony or a ‘reconstruction’ of what happened
4 brief general problems for EWT
Witnesses do not expect crimes, and may not pay close attention
Delays in questioning can be crucial, as memory degrades.
Context – was the account given at the crime scene or in court?
Emotions – emotions can often disturb memory performance, as can certain situations
What are the 3 factors affecting EWT
The spec wants us to look at 3 specific factors that affect EWT:
Misleading information: leading questions
Misleading information: post-event discussion
Anxiety
Describe study by Loftus and Palmer 1974
Sample: students
Watched film clips of car accidents and then gave them questions about the accident.
Critical question: ‘About how fast were the cars going when they …. each other?’
Five conditions of the IV - each given a different verb in the critical question:
Hit / contacted / bumped / collided / smashed
They then recorded the speed estimates given by the ppts and calculated an average speed estimate for each verb.
The verbs that suggest the cars were travelling at a higher speed (e.g., smashed) had a higher speed estimate than the verbs that suggested the cars were travelling at a slower speed (e.g., contacted).
These findings support the idea that leading questions significantly affect EWT.
Smashed= 40.8mph
contacted= 31.0mph
Describe study by Loftus and Zanni 1975
Loftus and Zanni (1975)
Method: Participants were shown a clip of a car accident. Some were asked “Did you see a broken headlight?” and others were asked “Did you see the broken headlight?” (the definitive.) There was no broken headlight in the film clip.
Results: 17% of the participants asked the definitive question replied that they had seen the broken headlight, while only 7% of those asked the non-definitive question said that they had.
Conclusions: The use of definitive or leading questions in an interview can lead to the creation of false memories by the eyewitness - thus eyewitness testimony is subject to inaccuracy and its reliability can be questioned. These findings offer compelling support to the idea even one word can make EWT less accurate.
Describe the study by Yuille and Cutshall 1986
Yuille and Cutshall (1986)
Method: 21 witnesses observed a shooting incident in which 1 person was killed and a 2nd seriously wounded. The incident took place on a major thoroughfare in mid-afternoon. All of the witnesses were interviewed by the investigating police, and 13 witnesses (aged 15–32 yrs) agreed to a research interview 4–5 mo after the event. In the present study, the eyewitness accounts provided in both the police and research interviews were analyzed.
Results: The witnesses were highly accurate in their accounts, and there was little change in amount or accuracy of recall over 5 mo. However, some aspects of color memory and age, height, and weight estimations were found to be erroneous. The eyewitnesses resisted leading questions, and their stress levels at the time of the event appeared to have no negative effects on subsequent memory. The findings above imply that laboratory findings about leading questions and EWT may be inaccurate.
Evaluation of research into leading questions: typically research is on only students
One issue with RESEARCH into leading questions affecting the accuracy of EWT is that typically the research was conducted on students. This creates problems generalising to the target population because…
Students may not be representative of the whole population. For instance, university students usually have an above average intelligence level and their memories may be more efficient because of this. Also, they tend to be of a younger age, and research has shown memory ability declines in older age, so we are not fully representing memory ability across age groups.
This means that study is limited in how far it can be used to explain the effect of leading questions on the accuracy of EWT as the findings cannot be generalised to everyone.
Evaluation of research into leading questions: practical applications
The research findings into the effects of leading questions on accuracy of EWT are strengthened by the fact that the research has led to useful PRACTICAL APPLICATIONS for society.
Research into leading questions has contributed to the development of the ‘enhanced cognitive interview’ used by the Police. This helps to reduce errors made by EWs by eliminating the use of leading questions as well as allowing the witness to initially report everything without interruption. Kohnken et al (1999) reviewed 53 studies and found this interview procedure led to a 34% increase in correct information.
This implies… that research into leading questions has had tangible effects in society by benefitted criminal investigations.
Evaluation of research into leading questions: high internal validity
One strength of research into leading questions is that most research in this area is well controlled LABORATORY experiments giving the research high INTERNAL VALIDITY. This means that we have increased confidence that it is the IV, not any EXTRANEOUS variables that is responsible for any changes in the DV.
For example, in the Loftus & Palmer experiment the IV was the verb given to the participants (smashed, collided, hit, bumped or contacted) within the critical question ‘About how fast were the cars going when they … each other’, which affected & changed the DV which was the estimation of the speed of the cars in mph. This means we can make statements about cause & EFFECT.
This means… the validity of the research strengthens the support it provides for the theory, making the theory that leading questions impact the accuracy of EWT more credible.
Evaluation of research into leading questions: low external validity
A weakness of the research used to investigate the effect of leading questions on EWT is that, because they are often LABORATORY experiments, they can be seen as being low in EXTERNAL validity.
This is because they take place in artificial and CONTROLLED settings that do not necessarily reflect REAL LIFE behaviour, like giving an EWT. In the above 2 studies on leading questions, the participants watched a film of a car accident: this is not the same as seeing a car accident in real life. For instance, seeing a car accident in real life is bound to create an emotional response in the witness, which could impact their ability to recall information as it is known anxiety can reduce recall. Also, the participants were told they were going to see a car accident, so they would have been paying attention. Usually, a witness doesn’t know an incident is about to take place and might be looking elsewhere when it happens, only catching the final moments of the event.
Therefore, it makes it difficult to GENERALISE the findings of such studies to real life eyewitness memory.
