how anxiety affect EWT accuracy

how anxiety affect EWT accuracy

1. anxiety has a negative affect

   • Deffenbacher et al. (2004)
     • they did a meta-analysis of 12 studies published between 1974 and 1997, looking at the effects of highlighted anxiety on accuracy of EW recall. From these studies it was clear that there was considerable support for the hypothesis that high levels of stress negatively impacted the accuracy of EW memory

2. anxiety enhances recall

   • Christianson and Hubinette (1993)
     • questioned 58 witnesses to real bank robberies. The witnesses that had been threatened in some way were more accurate in their recall, and recalled more details, than those who had been onlookers and less emotionally aroused. This continues to be true even 15 months later

3. weapon-focus effect

   • there is evidence that in violent crimes, arousal may focus on more central details of the attack (e.g. a weapon) than the more peripheral details (e.g. what else is going on)
     • Johnson and Scott (1976)
       • identified weapon-focus effect
   • in their initial experiment, Loftus et al. used two conditions, one using a weapon and one not. In both conditions ppts heard a discussion in an adjoining room. In condition 1 a man emerged with a pen and with grease on his hands. In condition 2 the discussion was rather more heated and a man emerged holding a paperknife covered in blood
     • when asked to identify the man from 50 photos, ppts in condition 1 were 49% accurate, compared with 33% accuracy in condition 2- suggesting that the weapon may have distracted attention from the person holding it, therefore explaining why EWs sometimes have poor recall for certain details of violent crime

4. evaluation

   • explaining the apparent contradiction
     • Deffenbacher suggests that this apparent contradiction in research findings could be best explained with reference to the Yerkes-Dodson law which states that performance improves with increases in arousal up to some optimal point and hen declines with further increases
       • many researchers believe that anxiety effects in EWT are curvilinear- meaning that small to medium increases in arousal may increase the accuracy of memory, but high levels interfere with accuracy
   • research supports the weapon-focus effect
     • a meta-analysis of studies concerned with the weapon focus effect (Steblay- 1992) showed that the presence of a weapon does indeed reduce the chances of a witness correctly identifying the person holding it
       • Loftus et al (1997) monitored EWs eye movements and found that the presence of a weapon causes attention to be physically drawn towards the weapon itself and away from other things such as the person's face