2.8 Anxiety - Factors affecting EWT

2.8 Anxiety - Factors affecting EWT

1. Yerkes-Dodson effect

   • States that when anxiety is at low and high levels, EWT is less accurate than if anxiety is at a medium level. Recall improves as anxiety increases up to an optimal point.

2. Negative effect on recall

   • Anxiety creates a physiological arousal in the body which prevents us from paying attention to important cues meaning recall is worse. Weapon focus is an explanation for forgetting.
   • Johnson and Scott (1976)
     • Procedure: Participants believed they were taking part in a lab study. While seated in the waiting room, there were two situations: In one a conversation was heard and a man came out holding a pen with grease on his hands, the other a man leaving with a knife covered in blood.
       • Findings: 49% who had seen the man with the pen were able to identify the man, but only 33% of those who had seen the bloody knife could identify him.
         • Tunnel theory of memory argues that people have enhanced memory for central events. Weapon focus as a result of anxiety can have this effect.

3. Positive effect on recall

   • Witnessing a stressful event creates anxiety triggering fight or flight increasing alertness and in turn improving memory.
   • Yuille and Cutshall (1986)
     • Procedure: Conducted a study of an actual shooting at a gun shop in Canada where the thief was shot dead. The witnesses were interviewed 4-5 months after the incident. Accuracy was determined by the amount of details correct with the police report. They were also asked how stressed they were during to assess anxiety.
       • Findings: Witnesses were accurate in their accounts. Those participants who reported high levels of stress were most accurate with an accuracy of 88% compared to 75% for less stressed group.

4. Evaluation

   • Weaknesses:
     • Extraneous variable. The witnesses who experienced the highest levels of stress were actually closer to the event so that may have had effects on their memory recall.
   • Strengths:
     • Support for negative effect. Study by Valentine and Mesout (2009) supports research on weapon focus. Researchers used an objective measure of heart rate to divide participants into low and high anxiety groups. Then they were asked to describe details about the actor in London Dungeon.
     • Support for positive effects. Christianson and Hubinette (1993) interviewed 58 witnesses to actual bank robberies and found that recall was best in high anxiety witnesses.