A01 A Factors affecting EWT

• Anxiety has a negative effect on recall

  Anxiety creates physiological arousal in the body which prevents us from paying attention to important cues so recall is worse. One approach to study EWT and A looks at effects of weapons on accuracy of recall on witness
• Procedure of weapon study

  Johnson and Scott led ppts to believe they're going to be in a lab study. While in waiting room, ppts heard argument in other room.
• Low anxiety condition

  Man walking through waiting room holding a pen with grease on his hands
• High anxiety condition


  Same argument but with accompanied sound of glass breaking. Man walked out with paper knife covered in blood
• Findings of weapon study

  Ppts looked at 50 pictures where 49% ppts identified man with pen and 33% ppts identified man with knife
• Tunnel theory

  Argues that a witness's attention narrows to focus on a weapon because its a source of anxiety
• Anxiety has a positive effect on recall

  Fight/flight response triggered increasing our alertness and improves memory
• Procedure of shooting experiment

  Cutshall and Yuille conducted research on real life shooting in gun shop in Canada. Shop owner shot thief dead and there were 21 witnesses where 13 agreed to take part in interviews 4-5 months after incident
• Witnesses in shooting experiment

  Their accuracy was determined by the number of details reported. Witnesses also asked to rate their stress levels using a 7 point scale and asked if they had emotional problems
• Findings of shooting experiment

  Witnesses were very accurate in their accounts and little change in their details. Some details were less accurate like age/height/weight. Pts with high stress levels were more accurate. 85% to 75% of non-stressed groups
• Explaining the contradictory findings

  Dodson and Yerkes argued that a relationship between emotional arousal and performance looks like an inverted u
• Deffenbacher


  Applied Yerkes-Dodson Law to EWT. When anxiety increases, memory increases. However, when person reaches optimal level of anxiety and eyewitness experiences any more than this stress, recall of event suffers a drastic decline