eyewitness testimony-anxiety Flashcards
(7 cards)
anxiety
Anxiety has strong physical and emotional effects on people.
However, it remains unclear whether or not these effects are positive or negative.
There is research to support both.
the negative impact-Johnson and Scott
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) is to look at the effect of the presence of a weapon which creates anxiety. This leads to a focus on the weapon, reducing a witness’s recall for other details of the event.
Procedure Craig Johnson and William Scott (1976) did research on this. Their participants believed they were taking part in a lab study. While seated in a waiting room participants in the low-anxiety condition heard a casual conversation in the next room and then saw a man walk past them carrying a pen and with grease on his hands. Other participants overheard a heated argument, accompanied by the sound of breaking glass. A man walked out of the room, holding a knife covered in blood. This was the high-anxiety condition.
Findings and conclusion The participants later picked out the man from a set of 50 photos, 49% 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 33%. The tunnel theory of memory argues that people have enhanced memory for central events. Weapon focus as a result of anxiety can have this effect.
the positive impact-Yuille and Cutshall
Witnessing a stressful event creates anxiety through physiological arousal within the body. The fight or flight response is triggered, increasing alertness. This may improve memory for the event as
we become more aware of cues in the situation.
Procedure John Vuille and Judith Cutshall (1986) conducted a study of an actual shooting in a gun shop in Vancouver, Canada. The shop owner shot a thief dead. There were 21 witnesses - 13 took part in the study. They were interviewed four to five months after the incident and these interviews were compared with the original police interviews 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 (on a 7-point scale) and whether they had any emotional problems since the event (e.g. sleeplessness).
Findings and conclusion The witnesses were very accurate in their accounts and there was little change in the amount recalled or accuracy after five 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). This suggests that anxiety does not have a detrimental effect on the accuracy of eyewitness memory in a real-world context and may even enhance it.
inverted U theory
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) reviewed 21 studies of EWT and noted contradictory findings on the effects of anxiety. He used the Yerkes-Dodson Law to explain the findings. When we witness a crime/accident we become emotionally and physiologically aroused. That is, we experience anxiety (emotional) as well as physiological changes in our body (the fight or flight response). Lower levels of anxiety/arousal produce lower levels of recall accuracy, and then memory becomes more accurate as the level of anxiety/arousal increases. However, there is an optimal level of anxiety, which is the point of maximum accuracy. If a person (or eyewitness) experiences any more arousal, then their recall
s-weapon focus
Valentine and Mesout (2009) carried out a study in the real-world setting of the Horror Labyrinth at the London Dungeon. It is designed to be frightening with many ‘scares’ such as darkness, screams, gory models and sudden movements. Visitors to the Labyrinth were offered a reduced entrance fee if they agreed to complete questionnaires at the end of their visit to assess their level of self-reported anxiety. They wore wireless heart monitors to confirm that they were experiencing anxiety. On the basis of these two measures participants were divided into two groups: high anxiety and low anxiety.
The participants’ task was to describe a person encountered in the Labyrinth (played by an actor). The researchers found that the high-anxiety participants recalled the fewest correct details of the actor and made more mistakes. The researchers also found that 17% of the high-anxiety group correctly identified the actor in a line-up compared to 75% correct identification by those in the low-anxiety group.
One strength is evidence supporting the view that anxiety has a negative effect on the accuracy of recall.
The study by Tim Valentine and Jan Mesout (2009, see right) supports the research on weapon focus, finding negative effects on recall. The researchers used an objective measure (heart rate) to divide participants into high- and low-anxiety groups. In this study anxiety clearly disrupted the participants’ ability to recall details about the actor in the London Dungeon’s Labyrinth.
This suggests that a high level of anxiety does have a negative effect on the immediate eyewitness recall of a stressful event.
limitation-unusualness not anxiety
One limitation of the study by Johnson and Scott (facing page) is that it may not have tested anxiety.
The reason participants focused on the weapon may be because they were surprised at what they saw rather than scared. Kerri 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 high 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.
strength-support for positive effects
Another strength is evidence showing that anxiety can have positive effects on the accuracy of recall.
Sven-Ake Christianson and Birgitta Hübinette (1993) interviewed 58 witnesses to actual bank robberies in Sweden. Some of the witnesses were directly involved (e.g. bank workers) and some were indirectly involved (e.g. bystanders). The researchers assumed that those directly involved would experience the most anxiety. It was found that recall was more than 75% accurate across all witnesses. The direct victims (most anxious were even more accurate.
These findings from actual crimes confirm that anxiety does not reduce the accuracy of recall for eyewitnesses and may even enhance it.
Counterpoint Christianson and Hübinette interviewed their participants several months after the event (four to 15 months). The researchers therefore had no control over what happened to their participants in the intervening time (e.g. post-event discussions). The effects of anxiety may have been overwhelmed by these other factors and impossible to assess by the time the participants were interviewed.
Therefore it is possible that a lack of control over confounding variables may be responsible for these findings, invalidating their support.
