Eyewitness testimony

Eyewitness testimony

• Rattler (1998) concluded that 50% of all wrongful arrest due to inaccurate identification by eyewitness

• The leading research an EWT is Elizabeth Loftus

• She carried out many lab experiments using stimulus material that mimic real life situations

• She said memories of the sum of what people have thought, what they have been told and what they believe

• Factors that can affect the accuracy of EWT:

  • Misleading information, including leading questions

  • Post event discussion

  • Anxiety

Misleading information: leading questions study

Key study: Loftus & Palmer (1974)

Aim: to investigate whether the precise wording of questions could affect the accuracy of memory

Procedure: participants watched a film of a car accident. They were then asked a crucial question,’ what speed were the vehicles travelling when they ___” A week later, participants were also asked if they had seen any broken glass

Findings: researchers found that what word was used affected the estimates of speed participants gave

Contacted = 32mph

Hit = 34mph

Bumped = 38mph

Collided = 39mph

Smashed = 41mph

Those in the smashed group also consistently more likely to answer yes wrongly to the broken grass question

Conclusion: the wording of the question affected the judgements of speed and did reduce the accuracy of EWT

post event discussion study

Gabbert et al (2003)

Aim: To investigate the effects of post event discretion on individuals who witnessed and then discuss a crime

Procedure: Gabbert’s sample consists of 60 students from the university of Aberdeen and 60 old adults recruited from a local community. Participants watched a video of a girl returning a book to a university office and stealing money from a wallet found in a desk drawer. The participant were tested on their recall of the event. There were two conditions in which participants were either tested individually (Control group) in pairs (Co-Witness group) The participants in the co-witness group were told that they had to watch the same video, however they had in fact in different perspectives of the same crime and only one person had actually witnessed the girl stealing. Participant in the co-witness group discussed the crime altogether. All of the participants then completed a questionnaire, testing their memory of the event.

Finding: 71% of the witnesses in the co witness group recall information had not actually seen compared with 0% of the control group. There were no age related differences.

Conclusion: These results highlight the issue of post event discussion and the powerful effect this can have on the accuracy of eyewitness testimony

misleading information and post event discussion evaluation summary

• valuable contributions

• positive applications

• lacking ecological validity

• serious consequences

misleading information and post event discussion evaluation - valuable contributions

Positive application: EWT research has made a valuable contribution to our understanding of EWT and has presented convincing evidence that post event information (leading questions or discussion) can affect the memory of the original event. Loftus findings were highly influential in the writing of The Devlin Report, which concluded that eyewitness testimony should not result in a conviction in an English court without other corroborating evidence.

misleading information and post event discussion evaluation - positive applications

Positive application: Research shows that EWT can be distorted significantly by post event information; this has significant implications for using eyewitness in courtrooms & the use of leading questions/discussion in police interviews. Consequently, this research has led to the development of the cognitive interview. This is a technique used by the police to improve the reliability of the evidence. Witnesses will be asked very few questions but instead will be asked to imagine themselves back at the scene of the crime. Such techniques are thought to be 35% more effective than standard police interviews.

misleading information and post event discussion evaluation - lacks ecological validity

However, much EWT work has been criticised for lacking ecological validity.

Studies are carried out in artificial lab environments, therefore the results may not generalise to real life eye witnesses. Firstly, the research is artificial because it lacks the stress and emotion of real life. Supporting evidence for this lack of emotion being a problem comes from a study of real robbery of gun shop in Canada which has shown that real life witnesses can recall information more accurately. Yuille & Cutshall (1986) examined the recall of witnesses to a shooting in a town in Canada. A man had attempted to rob a gun shop. During the course of the robbery the shop owner was shot. He returned fire, killing the would-be robber. The incident occurred in daylight, in front of a large number of witnesses. Some months after the event, Yuille and Cutshall tracked down the witnesses and asked to interview them. Fifteen of them agreed to take part in the study Examining the EWT accounts, Yuille and Cutshall made several important findings:

• The witnesses were able to recall the incident in a great amount of detail.

• There was a very high level of agreement between the accounts given by the different witnesses

• The witnesses accounts did not despite being asked leading questions.

Findings like these, which are obtained from real-world witnesses and hence are high in ecological validity cast doubt on the validity of Loftus'/Gabbert's conclusions

misleading information and post event discussion evaluation - serious consequences

Secondly the research is artificial because there are no consequences in lab experiments. It is possible that participants in experiments are less accurate than in real life because they know inaccuracies will not lead to serious consequences (e.g. people wrongly being sent to prison). Supporting evidence for this weakness comes from a study by Foster et al. (1994). Participants were shown a video of a bank robbery and were subsequently asked to identify the robber in an identity parade. Half the participants were led to believe that the robbery was real and that their responses would influence the trial. The other half assumed it was a simulation. Identification was more accurate in the first group, therefore suggesting that consequences are an important factor in the accuracy of EWT.

The effective anxiety and eyewitness testimony

According to the Yerkes-Dodson Law, an increase in anxiety improves performance but only up to a point. Once arouse has passed a critical point called the optimum, performance and recall tends to decline. This is likely to be because seeing violence raises witnesses arousal level past the optimal, leading to poor memory performance due to the heightened anxiety.

The weapon focus

The tendency for witnesses of violent crimes to focus their attention on the weapon used. Weapon focus usually results in poor quality eyewitness testimony, as the witness is unable to describe any useful aspects of the incident. The presence of a weapon will also increase anxiety levels once again disrupting recall.

Weapon focus and anxiety case study

Loftus (1979)

Aim: To investigate the effect of anxiety on recall

Procedure: participants were asked to wait in a room when they arrived for the start of an experiment. Participants didn’t realise that the experiment had actually started. During that time in the waiting room participants overheard either:

• Low-key discussion in a nearby lab about experiment failure. A person that emerged from the lab holding a pen with grease on his hands and left the room.

• A heated and hostile exchange from the lab. After the sound of breaking glass and crashing chair, a man emerged from the lab holding a paper knife covered in blood and left the room.

Participants were given 50 photos and asked to identify the man

Findings: Participants in the pen group of 49% accurate but the ninth group was only 33% accurate and identifying the man

Conclusion: This suggests that participants will less accurate in the second edition as they were focusing on the weapon which would have heightened their anxiety levels

the effect of anxiety on EWT evaluation summary

• positive applications

• lacks ecological validity

• evolutionary theory

• surprise not anxiety

the effect of anxiety on EWT evaluation - positive application

Positive applicatión: EWT research has made a valuable contribution to our understanding of EWT and has presented convincing evidence anxiety can affect the memory of the original event. Such research findings were highly influential in the writing of The Devlin Report, which concluded that eyewitness testimony should not result in a conviction in an English court without other corroborating evidence.

the effect of anxiety on EWT evaluation - lacks ecological validity

However, much EWT work has been criticised for lacking ecological validity. Research is artificial because there are no consequences for inaccurate recall of events. It is possible that participants in experiments are less accurate than in real life because they know inaccuracies will not lead to serious consequences (e.g people wrongly being sent to prison). Supporting evidence for this weakness comes from a study by Foster et al. (1994).

Participants were shown a video of a bank robbery and were subsequently asked to identify the robber in an identity parade. Half the participants were led to believe that the robbery was real and that their responses would influence the trial. The other half assumed it was a simulation.

Identification was more accurate in the first group suggesting that consequences are an important factor in the accuracy of EWT.

the effect of anxiety on EWT evaluation - evolutionary theory

The Yerkes-Dodson Law and Weapon focus both suggest that anxiety causes poor EWT. However, there is a contradictory argument that suggests that high anxiety/arousal actually creates more enduring and accurate memories. For example, evolutionary theory suggests that it would be adaptive to remember events that are emotionally important so that you could identify similar situations in the future & recall how to respond e.g. what you did the last time you escaped from a lion! This would be beneficial for survival, therefore Evolutionary theory would argue that anxiety should cause accurate EWT.

the effect of anxiety on EWT evaluation - surprise not anxiety

Research suggests that anxiety caused by weapon focus will reduce accuracy of EWT. However, a weakness of this is that it has been proposed that the reduction in recall is actually due to surprise (not anxiety). To test this Pickel (1998) arranged for Ps to watch a thief enter a hairdressing salon carrying scissors (high threat, low surprise), handgun (high threat, high surprise), wallet (low threat, low surprise) or a whole raw chicken (low threat, high surprise). Identification was least accurate in the high surprise conditions rather than the high threat. These findings support the view that the weapon focus effect is related to surprise rather than anxiety. Therefore casting doubts on the conclusion that anxiety caused by weapon focus causes inaccuracy in EWT.

Cognitive interviews techniques

1. Info is organised so that memories can be accessed in a number of ways

2. Memories are context dependent, meaning that retrieval may be more effective if the cues present at the time of storage are reinstated

What happens during a cognitive interview?

There are no set questions and there is no time limit so that when it says don’t feel time pressured. It involves asking questions. The interview remains silent and will not interrupt the witness. The interview will record proceedings and may take notes. Any clarification or elaboration is only when the recall seems to have ended

What are the four cognitive interview technique?

1. Reinstate the context

2. Change sequence

3. Change perspective

4. Report everything

Cognitive interview - Reinstate the context

The witness needs to be returned, in their mind, to the situation in which the event occurred. I attempt will be made to re-create the original mood and environment in the imagination of the interviewee which may increase recall. The witness may be asked to think back to before, during and after the event and recall where they were, what they were doing, their mood etc. This should produce context pendant retrieval cues to trigger extra detail details.

Cognitive interview - Change sequence

Traditional interviews might ask a witness to recall events in the order they occurred. Cognitive interviews were asked witnesses to recall events in different orders including reversing the older events. They should ensure the important details are not missed out and it might help to fill in any gaps

Cognitive interview - Report everything

Witnesses are encouraged to report everything even if info seems relevant. This unrestrained recall your details which might otherwise be mentally edited out and provides cues for other details

cognitive interview evaluation summary

• effective

• takes time

• depends on skill of interviewer

• each element is valuable

cognitive interview evaluation - effective

It is effective - Geiselman et al. (1984) published the first empirical test of the CI. With relatively little training, cognitive interviewers obtained up to 35% more correct details about simulated events than untrained interviewers with no increase in the number of errors. This result was replicated in numerous studies in which both children and adults were witnesses. More recently, the CI has been found to increase the reporting of correct details in adults with learning disabilities as witnesses, senior citizens and in children of preschool age.

cognitive interview evaluation - takes time

From their interviews with police, Kebbell & Wagstaff report a problem with the CI in practice. Police officers suggest that the technique requires more time than is often available and that instead they prefer to use deliberate strategies aimed to limit an eyewitness's report to the minimum amount of information that the officer feels is necessary. Getting information fast is often important to catch the criminal before they have time to escape.

cognitive interview evaluation - depends on skill of the interviewer

The cognitive interview is a form of communication and its success depends on the skills of the interviewer. Whilst interviewers can be trained, it is difficult to assess their competence as they are doing more than simply following a set of learned technical skills. Similarly, it is very easy for an inexperienced or slightly clumsy interviewer to ask questions that might be considered as 'leading' the witness. The accuracy of information from the cognitive interview may be subject to the same problems as regular interviews where the wording of the question might play a very significant role.

cognitive interview evaluation - each element is valuable

A strength of the cognitive interview is that each individual element has been found to be valuable. Each technique produces more information than the standard police interview. However, some aspects of the CI are more useful than others. A study found that using a combination of report everything and reinstate the context produced better recall than any of the other techniques. Therefore, some aspects of the CI are more useful than others, so perhaps the police should use these two techniques to interview witnesses even if the full CI isn't used