Factors Affecting Accuracy of EWT: post-event discussion

• post-event discussion


  conversation between co-witnesses or an interviewer and an eyewitness after a crime has taken place which may contaminate a witness' memory for the event.

  the memory of an event may also be altered or contaminated through discussing events with others and/or being questioned multiple times
• Gabbert


  A: to investigate the effect of post-event discussion on accuracy of EWT

  P: ppts were 60 students + 60 older adults

  they were tested individually or in pairs. each watched a video of the same crime but filmed from different PoV. this meant each person could see elements that the other couldn't

  pairs of ppts discussed what they had seen before being given an individual recall test

  F: 71% of ppts mistakenly recalled aspects of the event they hadn't seen in the video but had picked up from the other ppt. in the control group, where there was no discussion, this was 0%

  C: witnesses often go along with each other to gain social approval or because they thought the other person was right and they were wrong (memory conformity)
• Strength - practical applications

  if we know post-event discussion biases EWT, police can ensure they keep co-witnesses separate to avoid them contaminating their testimony, preventing miscarriages of justice
• Strength - population validity

  Gabbert et al tested 2 different populations

  found little difference between these 2 conditions

  therefore her results provide good population validity and allow us to conclude that post-event discussion affects younger + older adults in a similar way
• Weakness - unclear explanation of WHY post-event discussion distorts EWT

  Gabbert's results provide an insight into the effect of post-event discussion on the accuracy of EWT -> unable to conclude why the distortion occurs

  distortion could be the result of poor memory - people assimilate new info into their own accounts of the event

  it could be that the distortion occurs due to conformity + the social pressure from the co-witness

  Further research is required to answer this question
• Weakness - ecological validity

  ppts in the co-witness condition witnessed different perspectives of the same crime

  like Loftus Palmer, these witnesses knew they were taking part in an experiment and were more likely to have paid close attention to the details of the video clip

  these results don't reflect everyday examples of crime, where witnesses may be exposed to less info