factors affecting accuracy of EWT

• leading questions

  directs you towards a certain answer, directed towards answering in this way due to the wording of the question. Did you see the broken glass? How drunk was the perpetrator?
• substitution explanation

  the wording of the question changes the participants memory of the event
• response- bias explanation

  the wording of the question has no real effect on the participants memories but influences how they decide to answer
• post event discussion

  includes memory contamination and memory conformity
• memory contamination

  when co- witnesses discuss a crime, they mix (mis) information from the other witnesses/other people with their own memories
• memory conformity

  witnesses go along with each other to win social approval or because they believe the other witnesses are right
• bonder et al (2009)

  found that recall of the event was more accurate for those participants who has been warned that anything they hear from a co- witness is second hand info and they should forget it and recall only their own memory of the event
• anxiety weapon focus effect

  witness focuses their attention on the weapon being used in the crime, causes a state of anxiety which leads to difficulty in recalling and the other details accurately. As they are focused on the weapon and not anything else, weapon memory worse.
• Johnson and Scott (1976)

  participants are taking part in a lab study. Sat in waiting room, low anxiety a man walked in with pen and grease on hand . overheard argument high anxiety was a fake knife covered in blood. had to pick out the men from 50 photos, 49% of participants who saw the man (pen) identified him. 35 % identified the man with the knife.
• tunnel theory - Johnston and Scott (1976)

  attention is focused on weapon
• John guile and Judith cutshall (1986)

  real life situation, in a gun shop in Vancouver in Canada. Shop owner shot the thief dead. 21 witnesses - 13 agreed to be part of the study, interviews held 4-5 months after the incident. Witnesses were asked how stressed they were using the 7 point scale, witnesses were very accurate and little change in accuracy after 5 months, those who reported the highest levels of stress were most accurate (88% compared to less stressed 75%)
• contradictory findings to Johnson and Scott - John guile and Judith catchall (1986)

  presence of weapon - anxiety - better recall
• anxiety - inverted u hypothesis

  low anxiety - poor performance

  optimum anxiety level - best performance

  performance decreases past optimum anxiety

  aka Yerkes - Dodson law (1908)