Eyewitness Testimony; Anxiety

Eyewitness Testimony; Anxiety

1. Yerkes Dodson Law

   • Illustrates the relationship between anxiety and accuracy of EWT
   • Very low and very high levels of anxiety have a detrimental effect on memory recall
   • Moderate levels of anxiety are beneficial to performance

2. Negative Effect

   • Anxiety creates psychological arousal which prevents us from paying attention
   • Johnson & Scott
   • Aimed to show that anxiety as a result of a weapon can reduce accuracy of EWT
   • Weapon distracts attention from the perpetrators physical features and other events taking place
   • Procedure
     • Asked ppts to sit in a waiting room where they heard an argument in an adjoining room
     • Ppts saw a man run through carrying a pen covered in grease (low anxiety) or a knife covered in blood (high anxiety)
     • Ppts had to identify the man from a set of photos & accuracy was recorded
   • Findings
     • 49% could identify man with pen, 33% could identify man with knife
     • Used eye tracking equipment to show that wen a weapon is involved ppts attention is drawn to the weapon

3. Positive Effect

   • Fight or flight response increases alertness and improves recall
   • Yuille & Cutshall
   • Procedure
     • Real life shooting in a gun shop in Canada - shop owner shot a thief dead
     • 21 witnesses, 13 agreed to take part in study
     • Interviews held 4 months later and compared with police interviews
     • Accuracy determined by number of details reported in each account
     • Witnesses asked to rate how stressed they felt at the time using the 7 point scale, asked if they had problems since the event
   • Findings
     • Witnesses were very accurate in their accounts
     • Little change in the amount of accuracy (some details such as colours, age, height etc were less accurate)
     • Those who reported the highest levels of stress were the most accurate (88% compared to 75% for the less stressed group)