- Study 1 - Johnson and Scott: Anxiety has a negative effect:
- Procedure - They led participants to believe they were going to take part in a lab study. While seated in the waiting roomparticipants heard an argument in the next room. in the 'low-anxiety' condition: a man then walked through the waiting room carrying a pen with grease on his hands. In the 'high-anxiety' condition: the heated argument was accompanied by the sound of breaking glass. A man then walked through the waiting room holding a paper knife covered in blood. The participants were the asked to pick the man out from a set of 50 pictures.
- Findings - 49% of the participants in the low-anxiety condition were able to identify him. The corresponding figure for high-anxiety participants was just 33%. The tunnel theory of memory argues that a witness' attention is on the weapon (weapon focu), because it is a source of danger and anxiety.
- Study 2 - Yuille and Cutshall: 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 ncident.
- Findings - Witnesses were very accurate and there was little cahnge 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…