Eye Witness Testimony

Leading questions

Loftus and Palmer (1974) - 45 students shown several films of road traffic incidents & then given a questionnaire to describe the accident & answer a series of questions about their observation. One critical question varied between condidions with one group asked how fast the vehicles were going when they 'hit' each other while other groups has verbs implying different degrees of collision such as 'bumped, smashed, contacted, collided'. Results found the world that implied a stronger collision resulted in greater average estimates of speeds from participants. Those exposed to 'smashed' gave the highest estimates (41mph) while contacted resulted in the lowest speed estimate (30mph), demonstrating how leading questions could influence memory recall. 

The experiment was recreated with another group with the verbs 'smashed' and 'hit' while a control group was not exposed to such leading questions. They were questioned 1 week later and asked a series of questions with one critical question being whether they witnessed any broken glass, There was no broken glass in the film however results found that those exposed to 'smashed' were more likely to report seeing broken glass. This highlighted how misleasding information post-event can change the way information is stored or recalled.

Leading questions 

Loftus and Pickrell (1995) conducted a study into how misleading information could create false memories in individuals. 24 Ps ranging from 18-53 were giving 4 stories about their childhood gathering from relatives. 3 of the stories were true while one was false and it included being lost in a department store when ages 5 and an elserly lady rescuing them. Ps were then asked questions on whether they recalled these stores and results fould 29% of the fake stories were recalled by Ps believing them to be true. 68% of the true stories were recalled correctly also. This highlighted how false memories could be created from suggestion and misleading information. 

Real life tudies outside the lab setting by Yuile and Cutshall have found that witnesses to real events tended to have accurate recall even many months after witnessing events with misleading questions having little affect suggesting previous findings by Loftus into leading questions may possibly be limited to lab settings. Forster et al found supporting evidence for this in one study where Ps who tought they were watching a real life robbery and believed their responses would have an impact on an upcoming trial actually be more accurate in their recall.

The strength of Loftus' studies is that the lab consitions allowed researchers to control for extraneous confounding variables and clearly see the link between leading questions and recall. The lab settings also make it easier to establish cause and effet relationships between leading questions and memory recall which would be difficult to do in real world settings. 

One weakness here is that studies are lab studies and therefore lack ecological validity and realism. Due to this the results gained in such settings may lack external validity and wider generalism. The use of students in lab studies may have been a counfounding variable in itself rather than leading questions as they are not representative of the ranges of ages in the normal population and therefore the sample lacks population validity.

Also research suggests age may be a confounding variable in itself when it comes to leading questions with Warren et al finding younger children were more susceptible to influence to misleading information than older. Therefore this study may lack internal validity as it may be more of a measure on how leading questions affects one particular age group rather than the wider population.

The use of questionnaires is also another possible weakness as questions can be easily misunderstood by Ps or misinterpreted without clarification. People's responses may also be misunderstood by researchers. 

Deffenbacher reviewed 21 studies finding the stress-performance relationship followed an inverted U as proposed by the Yerkes-Doson Curve. This means that the efficiency of EWT depended on the level of stress/anxiety with low and high amounts of anxiety resulting in poorer recall while modert elevels of anxiety yielded thebest and most optimum level of recall and performance. The practical application here is that establishing eye witness level of arousal/anxiety may be key in court evidence to determine the validity of their account. However, this in itself is likely to be difficult and purely based on a subjective measure in itself. 

Loftus et al found similar findings when two groups in different conditions observed a violent and non-violent event. In condition 1 a man exited a discussion holding a pen while condition 2 saw a man existing holding a paperknife covered in blood after a loud altercation. The group who observed the pen were more accurate (33%). A possible explanation is the weapon may have distrated their attention from everything else happening and may explain why some witnesses struggle for other details in violent crime as their focus switches to the weapon. 

Clifford and Scott found that people who saw a film of a violent attack remembered less than people in a control group who saw a less stressful version. They concluded that witnessing stressful situations in real life will be far more stressful than observing a film and memory accuracy may well be affected in real life with poorer recall.

General criticisms and strengths of lab studies - demand characterisytics, lacking ecological validity however, easily replicable, establish cause and effect relationships. Due to this other studies have found Deffenbacher and Loftus' results to be reliable. 

Yuille & Cutshall's study contradicts lab findings however showing the importance of stress in EWT. Witnesses to a real life violent crime (a bank robbery) were found to have accurate memories 5 months after the event; even with misleading Qs which were in the questioning. 

Studies that have found stress/anxiety to aid recall were likely to have experienced the first increasing levels of stress in the Yerkes-Dodson curve while those suffering from poor recall may be due to them being within the second part with over-arousal resulting in poor recall performance. Such studies involving violence to heighten anxiety levels also raise ethical concerns. 

there is also research to suggest the Yerkes-Dodson curve is far too simplified to explain how anxiety affects EWT. Fazey & Hardy's (1988) Catastrophe theory may be a better explanation. This includes performance, psychological arousal (PA) and cognitive anxiety. This proposes that as PA increases beyond the moderate optimum level, unlike the curve where there's a steady decline, a drastic drop in performance is caused by increasing anxiety and worry. 

Is a conversation between co-witnesses after a crime which may contaminate the witness's version of events. 

Gabbert et al (2004) - Two groups of Ps, young adults (17-33) and older adults (58-80). Both groups wathed a staged crime and wereexposed to misleading information in one of two ways. Through conversation with a confederate or reading a written report of the crime, supposedly wrtten by another P. The Ps were then given a recall test about the event they witnessed. It was found that both groups were more likely to report innacurate information after a conversation with a confederate than after reading the report. 

Fisher and Geiselman (1972) argued that EWT could be improved if the police used better techniques when interviewing witnesses. They recommended such techniques should be based on psychological insights into how memory works, and called this the cognitive interview. 

• Report everything: Witnessses are encouraged to include every detail of the event, even though it may seem irrelevant or the witness doesn't feel confident about it. Seemingly trivial details may be important and, may trigger more important memories. 
• Reinstate the context: The witness should return to the original crime scene and imagine the environment. This is related to context-dependent forgetting. 
• Reverse the order: Events should be recalled in a different chronological order to the original sequence. This is done to prevent people reporting their expectations of how the event must have happened rather than the actual events. It also prevents dishonesty.
• Change perspective: Witnesses should recall the incident from other people's perspectives. This is done to disrupt the effect of expectations and schema on recall. The schema you have for a particular setting generate expectations of what would have happened and it is the schema that is recalled rather than what really happened. 

Fisher et al (1987) developed some additional elements of the CI to focus on the social dynamics of the interaction. For example, the interviewer needs to know when to establish eye contact and when to relinquish it. The enhanced CI also includes ideas such as reducing eyewitness anxiety, minimising distractions, getting the witness to speak slowly and asking open-ended questions. 

• -Police may be reluctant to use the CI becaise it takes much more time than the standard police interview. More time is needed to establish rapport with the witness and allow them to relax. The CI also requires special training and many forces have not been able to provide more than a few hours. It's unlikely that the proper version of the CI is actually used. 
• + Milne and Bull (2002) found that each individual element was equally valuable. Each technique used singly produced more info than the standard police interview. However, they found that using a combination of report everything and context reinstatement produced better recall than any of the conditions. Confirmed police officers' suspicions that some aspects of the CI are more useful than others. Proves the CI helps EWT for the police.
• + Research suggests that the enhanced CI may offer special benefits. For example, a meta-analysis by Kohnken et al (1999) combined data from 50 studies. The ECI consistently provided more correct information than the standard interview used by the police. This is a strength because it gives the police a greater chance of catching criminals. 
• - The techniques of the CI aim to increase the amount of correct information but the recall of incorrect information may also be increased. Kohnken (1999) found an 81% increase of correct information but a 61% increase in incorrect information when CI compared to standard interview.