The role of Anxiety

• Yerkes-Dodson: Inverted-U theory of arousal

  Deffenbacher reviewed 21 studies and found a stress performance relationship followed an inverted U function. He suggested that the accuracy of EWT depends upon the level of anxiety. Accuracy is impaired when there is too much or too little anxiety. Accuracy increases when a moderate level of anxiety is experienced.
• weapon focus effect

  concentration from witnesses on a weapon in a crime scene results in reducing ability to remember details about the crime.
• Johnson and Scott - weapon focus effect study - Procedure

  PP were told to wait in a reception area for the experiment to start but it already started when the receptionist left the room. It was an independent group design study: condition 1 - no weapon/low anxiety - PP heard talking in the lab about a piece of equipment being broken and then an individual came out with a pen and greasy hands and condition 2 had weapon/high anxiety - PP overheard a heated argument which lead to smashing chairs and glass breaking and then an individual came out holding a knife with bloody hands.
• Johnson and Scott - weapon focus effect - results

  49% could correctly recall the man holding the pen with greasy hands compared to 33% correctly recalling the man holding the knife with bloody hands. This suggests the PP exposed to the knife had higher levels of anxiety so more likely to focus their attention on the weapon and not the appearance of the target.
• Christianson and Hubinett - bank robbery

  They interviewed 110 witnesses of a real bank robbery 4-15 months after it happened. Their original and recent statement were compared and assessed for accuracy. All witnesses showed good recall but the bank tellers statement was most accurate who had high anxiety which suggests high anxiety does not affect accuracy of EWT.
• Evaluation of role of anxiety

  -methodological issues: Johnson and Scott's research lacks mudane realism as PP knew they were part of a study so may have paid more attention to details. Can't generalise findings to real life.

  Christianson and Hubinett - high ecological validity as it was a real crime so EWT is more generalisable. However there is the issue of proximity being a confounding variable.

  +real life studies increases ecological validity so can be generalised to real life. Real experienced stress and anxiety so more realistic and accurate results from EWT.
• Yullie and Cutshall - challenges weapon focus


  Shopkeeper shot a thief dead. 21 witnesses were interviewed by the police. 4-5 months later 13 agreed to take part in study and then both interviews were compared. High levels of accuracy in their description 5 months later (asked how stressed they were during the event on a point scale up to 7). Results: refute weapon focus effect as shows real life cases of anxiety so accuracy of EWT increases. Findings have a greater impact as higher ecological validity and more representative.