Factors Affecting EWT Accuracy: Anxiety

• Define 'anxiety'

  A state of emotional and physical arousal. The emotions include having worried thoughts or feelings of tension. Physical changes include an increased heart rate and sweatiness. Anxiety is a normal reaction to stressful situations, but it can affect accuracy and detail of EWT.
• Anxiety has a negative affect on recall: Weapon focus


  - Johnson and Scott (1976) conducted research into weapon focus.

  - 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, followed by a man carrying a pen and with grease on his hands walking out.

  - In the high-anxiety condition, participants overheard a heated argument and breaking glass, followed by a man walking out with a bloody knife.

  - Later, the participants had to identify the men from a group of 50 photos.

  - 49% in the low-anxiety condition were able to identify the man, compared to 33% in the high-anxiety condition.

  - The tunnel theory of memory argues that people have enhanced memory for certain events. Weapon focus as a result of anxiety can have this effect.
• Anxiety has a positive effect on recall


  - Research conducted by Yuille and Cutshall (1986).

  - They investigated an actual shooting in a gun-shop in Vancouver, Canada where the shop owner shot a thief dead.

  - There were 21 witnesses, 13 of which participated.

  - The participants were interviewed 4-5 months after the event. These interviews were then compared to the police interviews that took place at the time.

  - Accuracy of recall was measured by the number of details remembered.

  - The witnesses also had to use a 7-point scale to rate how stressed they felt and if they experienced any emotional problems such as sleeplessness.

  - Overall, the witnesses were very accurate in their recounts, though some details were less accurate, such as age, weight and height estimates.

  - Those who reported higher levels of stress were the most accurate (88% accuracy compared to75% accuracy in the less-stressed group.

  - Yuille and Cutshall (1986) suggests that anxiety does not have a negative impact on recall and EWT accuracy in a real-world context.
• Explaining the contradictory findings of Johnson and Scott (1976) and Yuille and Cutshall (1986)


  - Yerkes and Dodson (1908) suggested that he relationship between emotional arousal and recall looks like an inverted U.

  - Deffenbacher (1983) reviewed 21 EWT studies and used the Yerkes-Dodson law to explain the contradictory findings of anxiety and EWT studies.

  - When we witness a crime, we become emotionally and physiologically aroused, i.e. we experience anxiety.

  - Lower levels of anxiety produce lower levels of accuracy, and then memory accuracy increases as anxiety increases. There is also an optimal point of anxiety which produces the most accurate recall, however any more arousal after this point will lead to a drastic decline in accuracy.
• Evaluating anxiety: Unusualness not anxiety

  - A limitation of Johnson and Scott's (1976) study is that it may not have tested anxiety.

  - Participants may have focused on the weapon as they were surprised rather than scared.

  - Pickel (1998) conducted a similar experiment using scissors, a handgun, a wallet and a raw chicken. The study was done in a hairdressing salon where the scissors and wallet would be 'normal' items and the handgun and raw chicken would be considered unusual.

  - Pickel's study suggests that the weapon focus effect is as a result of unusualness rather than anxiety or a threat.
• Evaluating anxiety: Support for negative effects


  - A strength is evidence supporting the view that anxiety has a negative effect on recall.

  - Valentine and Mesout's (2009) research supports weapon focus research and its negative effects on recall.

  - The researchers used heart rate as an objective measure of anxiety, and from this, divided participants into a high or low-anxiety groups.

  - In the study, anxiety clearly disrupted the participants' ability to recall details about an actor in the London Dungeon's labyrinth.

  - This suggests that anxiety has negative effect on the immediate eyewitness recall on a stressful event.
• Evaluating anxiety: Support for positive effects (with counterpoint)

  - Another strength is that there is evidence showing that anxiety can have a positive effect on recall.

  - Christianson and Hübinette (1993) interviewed 58 witnesses of bank robberies in Sweden. Some witnesses were directly involved (bank employees) and others were indirectly involved, i.e. bystanders.

  - The researchers assumed that those directly involved would have experienced the most anxiety. They found that recall was over 75% accurate across all witnesses. The direct victims had an even higher accuracy.

  - These findings confirm that anxiety does not reduce recall accuracy, and may even enhance it.

  
  

  - Counterpoint: Christianson and Hübinette interviewed their participants 4-15 months after the event. Therefore, the researchers had no control over what happened to the participants between the robbery and the interview, e.g. post-event discussion.

  - The effects of anxiety may have been overwhelmed by these factors and impossible to assess when the participants were interviewed.

  - As a result, it is possible that there was a lack of control over confounding variables, which invalidates their results.
• Evaluating anxiety: Problems with the Yerkes-Dodson law

  - The inverted-U theory seems to be a reasonable explanation of contradictory findings across anxiety studies.

  - However, it ignores the fact that anxiety is multi-faceted, it has cognitive, behavioural, emotional and physical aspects.

  - The inverted-U theory focuses only on the physical aspects of anxiety, and assumes this is the only element linked to EWT.

  - For example, the way we think (cognitive) may be important, but the Yerkes-Dodson law disregards this.