ewt: anxiety

• study 1: Johnson + Scott(1976) anxiety has a negative effect

  procedure: pp's sat in a waiting room believing they were going to take part in a lab study. Each pp heard an argument in the next room

  • low-anxiety condition : a man when walked through the waiting room carrying a pen with grease on his hands
  • high-anxiety condition: the heated argument was accompanied by the sound of breaking glass. a man then walked through the room holding a paper knife covered in blood

  pp's were later asked to pick the man from a set of 50 photographs
• study 1: Johnson + Scott(1976) anxiety has a negative effect

  findings + conclusions : 49% of pp's in the low-anxiety condition were able to identify him. the corresponding figure for high-anxiety pp's was just 33%. the tunnel theory of memory argues that a witness's attention is on the weapon (weapon focus), because it is a source of danger + anxiety
• study 2: Yuille + cutshall (1986) anxiety has a positive effect


  procedure: In a real-life crime a gun-shop owner shot a thief dead. There were 21 witnesses, 13 agreed to participate in the study.

  Participants were interviewed 4-5 months after the incident. Accounts were compared to the police interviews at the time of the shooting. Witnesses rated how stressed they felt at the time of the incident
• study 2: Yuille + cutshall (1986) anxiety has a positive effect


  findings: Witnesses were very accurate and there was little change after 5 months. Some details were less accurate, e.g. colours of items, and age/weight/height.

  Participants who reported the highest levels of stress were most accurate (about 88% compared to 75% for the less-stressed group)
• explaining the contradictory findings

  • 'inverted u' theory. - Yerkes and Dodson (1908) argue that the relationship

  between performance and arousal/stress is curvilinear rather than linear

  • Affects memory - Deffenbacher (1983) found that lower levels of anxiety did produce lower levels of recall accuracy. Recall accuracy increases with anxiety up to an optimal point. A drastic decline in accuracy is seen when an eyewitness experiences more anxiety than the optimal point.
• limitation - Johnson + Scott's study is that it may test surprise not anxiety

  pp's may focus on a weapon because they are surprised at what they see rather than because they are scared. Pickel (1998) used scissors, wallet, raw chicek as hand-held items in a hairdressing salon. EWT accuracy was poorer for high unusualness. so the weapon focus effect is due to unusualness rather than anxiety/threat and therefore tells us nothing specifically about the effects of anxiety on ewt
• strength - Yuille & Cutshall's study is ecologically valid. It uses real life data which makes it more reliable. The participants had experienced the event firsthand. This means their memories will be fresh and vivid. They also have no reason to lie or exaggerate their recollection. Therefore we can trust the results of this experiment.
• weakness - Yuille & Cutshall's study is limited by its small sample size. Only 13 out of 21 witnesses participated in the research. This limits the generalisability of the findings. We cannot say that all witnesses would show similar patterns of behaviour. Also, only 13 people took part meaning that the results could be chance findings. More participants need to be tested to ensure the reliability of the findings.
• weakness - Yuille & Cutshall's study lacks control over variables. We cannot say whether the increased accuracy is caused by anxiety or other factors such as the passage of time. Participants could have been influenced by media coverage of the case. Also, some people might feel anxious even if they don't report feeling anxious. So we do not know whether the increase in accuracy is due to anxiety or something else entirely.