A01

• Define anxiety

  A state of emotional and physical arousal
• What is the Yerkes-Dodson Law?

  States that extreme anxiety (too high or too low) reduces EWT accuracy and moderate anxiety enhances EWT accuracy
• What is the weapon focus effect?

  A weapon in a criminal's hand distracts attention from other features (because of the anxiety it creates) and therefore reduces the accuracy of identification of the perpetrator in a crime.
• Name the study which shows the negative effect of anxiety on EWT accuracy (weapon focus effect)

  Johnson and Scott (1976)
• Describe the procedure and findings of the study which shows the negative effects of anxiety on EWT accuracy


  - participants were asked to wait in a reception area of a lab where they overheard an argument in the next room before a man leaves the room. There were 2 conditions:

  1. low anxiety condition -> participants overheard argument in lab and man walks out holding a pen, with hands covered in grease

  2. high anxiety condition -> participants overheard heated argument, sound of breaking glass and crashing chairs before a man runs out holding a bloodied letter opener

  - both groups were shown 50 photos and asked to identify the man they saw leaving the room

  - findings showed 49% accuracy in the low anxiety condition and 33% accuracy in high anxiety condition
• Name two studies which show the positive effect of anxiety on EWT accuracy

  1. Yuille and Cutshall (1986) - Canadian robbery

  2. Christianson and Hubinette (1993) - Swedish bank robbery
• Describe the procedure and findings of Yuille and Cutshall (1986)

  - real-life shooting in a Canadian gun shop where shop owner shot thief dead

  - witnesses were interviewed 3-5 months later and compared with the original police interview made at the time of the shooting

  - witnesses were asked to rate how stressed they had felt at the time of the incident

  - it was found that witnesses accounts were very accurate and there was little change in accuracy after 5 months

  - participants with highest stress were most accurate (about 88% compared to 75% for less-stressed group)
• Describe the procedure and findings of the Christianson and Hubinette study (1993)

  - questioned 58 real witnesses to Swedish bank robberies

  - witnesses were either victims (bank teller = high anxiety) or bystanders (employee/customer = low anxiety)

  - interviews were conducted 4-5 months after robberies

  - it was found that all witnesses had good memories for details of robbery and the most anxious witnesses (victims) had the best recall