Factors affecting eyewitness testimony PDF

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in depth notes on the subtopics for independent reading for the dd102 module...

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Factors affecting eyewitness testimony – anxiety

The effects of anxiety Anxiety has strong emotional and physical effects. But it is not clear whether these effects make eyewitness recall better or worse. There is research to support both possibilities. Anxiety has a negative effect on recall Anxiety creates physiological arousal in the body which prevents us paying attention to important cues, so recall is worse. One approach to studying anxiety and eyewitness testimony (EWT) has been to look at the effect of weapons (which create anxiety) on accuracy of recall of the witness. Procedure Johnson and Scott (1976) did research on this. They led participants to believe they were going to take part in a lab study. While seated in a waiting room participants heard an argument in the next room. In the ‘low-anxiety’ condition a man then walked through the waiting area, carrying a pen and with grease on his hands. Other participants overheard the same heated argument, but this time accompanied by the sound of breaking glass. A man walked out of the room, holding a paper knife that was covered in blood. This was the ‘high-anxiety’ condition. Findings The participants later picked out the man from a set of 50 photos; 49% of the participants who had seen the man carrying the pen were able to identify him. The corresponding figure for the participants who had seen the man holding the blood-covered knife was just 33%. The tunnel theory of memory argues that a witness’s attention narrows to focus on a weapon, because it is a source of anxiety. Anxiety has a positive effect on recall The stress of witnessing a crime or accident creates anxiety through physiological arousal within the body. The fight-or-flight response is triggered which increases our alertness and improves our memory for the event because we become more aware of cues in the situation. Procedure John Yuille and Judith Cutshall (1986) conducted a study of a real-life shooting in a gun shop in Vancouver, Canada. The shop owner shot a thief dead. There were 21 witnesses – 13 agreed to take part in the study. The interviews were held 4–5 months after the incident and these were compared with the original police interviews made at the time of the shooting. Accuracy was determined by the number of details reported in each account. The witnesses were also asked to rate how stressed they had felt at the time of the incident, using a 7-point scale, and asked if they had any emotional problems since the event, such as sleeplessness. Findings The witnesses were very accurate in their accounts and there was little change in the amount or accuracy after 5 months – though some details were less accurate, such as recollection of the colour of items and age/height/weight estimates. Those participants who reported the highest levels of stress were most accurate (about 88% compared to 75% for the less-stressed group). Explaining the contradictory findings According to Robert Yerkes and John Dodson (1908) the relationship between emotional arousal and performance looks like an ‘inverted U’ (see graph below).

Kenneth Deffenbacher (1983) applied the Yerkes-Dodson Law to EWT. Lower levels of anxiety produce lower levels of recall accuracy. But memory becomes more accurate as the level of anxiety experienced increases, just as you would expect from the graph. However, there comes a point where the optimal level of anxiety is reached. This is the point of maximum accuracy. If an eyewitness experiences any more stress than this, then their recall of the event suffers a drastic decline

Stressful situations create anxiety. Crimes and accidents are no exception. When we witness such events, we experience physiological and psychological changes that could affect what we later remember. So now we turn our attention to the second major factor that can affect the accuracy of EWT – anxiety. Key terms Anxiety – A state of emotional and physical arousal. The emotions include having worried thoughts and feelings of tension. Physical changes include an increased heart rate and sweatiness. Anxiety is a normal reaction to stressful situations, but can affect the accuracy and detail of eyewitness testimony.

Evaluation Weapon focus effect may not be relevant The study by Johnson and Scott (facing page) on the weapon focus may test surprise rather than anxiety. The reason participants focus on the weapon may be because they are surprised at what they see rather than because they are scared. Pickel (1998) conducted an experiment using scissors, a handgun, a wallet or a raw chicken as the hand-held items in a hairdressing salon video (where scissors would be low anxiety, low unusualness). 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/threat and therefore tells us nothing specifically about the effects of anxiety on EWT. Field studies sometimes lack control Researchers usually interview real-life eyewitnesses sometime after the event. All sorts of things will have happened to the participants in the meantime that the researchers have no control over – discussions with other people about the event, accounts they may have read or seen in the media, the effects of being interviewed by the police, and so on (i.e. post-event discussions). This is a limitation of field research because it is possible that these extraneous variables may be responsible for the accuracy of recall. The effects of anxiety may be overwhelmed by these other factors, and impossible to assess by the time the participants are interviewed. There are ethical issues Creating anxiety in participants is very risky. It is potentially unethical because it may subject people to psychological harm purely for the purposes of research. This is why real-life studies are so

beneficial – psychologists interview people who have already witnessed a real-life event, so there is no need to create it. This issue doesn’t challenge the findings from studies such as Johnson and Scott but it does question the need for such research. One reason is to compare findings with the less controlled field studies – and the benefits of this research may outweigh the issues.

Evaluation eXtra The inverted-U explanation is too simplistic Anxiety is very difficult to define and measure accurately. One reason for this is that it has many elements – cognitive, behavioural, emotional and physical. But the inverted-U explanation assumes only one of these is linked to poor performance – physiological (physical) arousal. Consider: Explain why the inverted-U theory is an incomplete explanation of how anxiety affects EWT. Is there more to the relationship between anxiety and EWT than just physiological arousal, for instance? Demand characteristics operate in lab studies of anxiety Most lab studies show participants a filmed (and usually staged) crime. Most of these participants will be aware they are watching a filmed crime for a reason to do with the study. Chances are most of them will work out for themselves that they are going to be asked questions about what they have seen. Consider: How might demand characteristics affect the way participants respond? What might make them more or less accurate in their recall?...