Aim: investigate how post-event leading questions affect EWT accuracy
Sample: 150 students
Method: lab experiment + IM design
Procedure:
Ppts shown short video of multi-vehicle crash
Ppts asked "how fast were the cars going when they hit/smashed into each other?"
One week later: ppts asked if they saw broken glass (there was none in the video)
Loftus + Palmer1974 - STUDY 2 (factors affecting EWT accuracy)
Findings: 'smashed' = more reports of broken glass than 'hit'
Conclusions: leading questions cause altered memories, not just response-bias
Gabbert et al. 2003 (factors affecting EWT accuracy)
Aim: investigate effect of post-event discussion on EWT accuracy
Sample: 60students from Uni of Aberdeen + 60older people from local community
Method: lab experiment + IM design
Procedure:
Ppts shown video of girl stealing money from a wallet
Experimental group discussed whether she stole the money with 'co-witness' -> both told they watched the same video but one person actually watched a different one with more detail
They both filled in questionnaire about the video afterwards
Control group filled in questionnaire without discussion
Gabbert et al. 2003 (factors affecting EWT accuracy)
Findings: 71% of experimental witnesses recalled details they hadn't seen + 60% said she was guilty despite not actually seeing her commit the crime
Conclusions: people = prone to 'memory conformity' -> post-event discussion = altered memory/reduced EWT accuracy