anxiety on EWT

• what is anxiety

  an unpleasant emotional state that is often accompaied by increased heart rate and rapid breathing
• what effects does anxiety have on EWT

  it has been suggested that it has a negative effect

  and a positive one
• who researched the negative effects of anxiety on ewt

  johnson and scott
• johnson and scott procedure

  -participants left in a waiting room waiting for the 'real' study to start

  2 conditions:

  1) participants overhear an argument followed by a man leaving with a grease covered pen

  2) participants overhear an argument followed by a man leaving with a blood covered paper knife
• johnson and scott findings and conclusion

  when asked to identify the man from 50 photos

  - 49% identified man with the pen

  - 33% identified the man with the knife

  
  

  this suggest higher anxiety associated with seeing a knife reduces the accuracy of ewt

  + there is a weapon focus effect
• what is the weapon focus effect

  where a witnesses attention is drawn to the weapon and excludes other details
• why does the weapon focus effect support the effect of anxiety on ewt

  the prescence of a weapon is likely to increase anxiety

  - we focus on the weapon which could cause us harm instead of other details like the mans face

  
  

  this explains why identification was poor in the knife condition but in the pen, their attention was not needed on the pen
• who researched positive effects of anxiety on ewt

  christianson and hubinette
• how did christianson and hubinette study positive effects of anxiety

  they questioned 58 real witnesses to bank robberies in sweden

  they were either the bank tellers or bystanders and therefore high or low anxiety respectively
• christianson and hubinette results and conclusion

  the researchers found that all witnesses showed generally good memories for details, better than 75% accuracy and that the witnesses who were most anxious (the bank tellers) had the best recall

  
  

  this shows that anxiety does not reduce accuracy
• explanation of why anxiety increases accuracy

  the flight or fight responce

  - a stressful event readies the body for fight or flight

  -psychological arousal increases alertness which improves memory for an event because we become more aware of cues in the situation
• how can the two effects of anxiety on accuracy be explained

  the yerkes dodson effect

  
  

  essentially:

  - the principle that the effect of anxiety on accuracy is a bell shaped curve and has an optimum level of anxiety which maximises recall but any higher than this and recall begins to become less accurate
• who evaluated the weapon focus effect

  pickel
• pickels procedure


  participants watched a theif entering a hair salon with 4 diff items, measured in suprise and threat

  
  

  a gun : high threat + surprise

  scissors : high threat + low surprise

  a wallet : low threat + low surprise

  a raw chicken : low threat + high surprise
• results + conclusion of pickels study

  correct identification was lowest in the high surprise conditions rather than the high threat

  
  

  this suggests that the weapon focus effect is actually related to surprise rather than anxiety
• more negative evaluation for effect of anxiety on ewt

  natural experiments (C+H) sometimes lack control

  - many extraneous variables eg proximity to incident and previous training potentially given to react to a robbery

  
  

  demand characteristics in lab studies (J + S)

  
  

  individual differences

  - some people may be more sensitive to the effects of anxiety

  - it has been investigated and people described as stable have accuracy increased by anxiety and people who are neurotic have accuracy decreased by anxiety

  
  

  ethics

  - protection from harm