Eyewitness Testimony - Post-Event Discussion

Psychology: AQA A Level, topic 2.1.15

Gabbert et al (2004) - Staged Crime

Research aim: To investigate the effect of post-event information on accuracy of recall.

Laboratory experiment.
60 students from the University of Aberdeen and 60 local older adults were the participants.

Participants were allocated to one of two groups.
The control group individually watched a video of a girl stealing a wallet.
The experimental group (co-witness group) were put into pairs and watched the video individually. They were told it was the same video, but one half of the pair saw the scene from a different perspective and did not actually see the girl steal the wallet.
The co-witness group were then allowed to discuss what they had seen.
All participants then completed a questionnaire to test their memory of the event.

Results:
71% of the co-witnesses reported remembering information that they had not actually seen.
60% said she was guilty despite not seeing her commit the crime.
Conclusion: Participants in the co-witness group were influenced by the post event information given to them by their partner.

Strengths
Reliable – easy to replicate.
Practical applications – demonstrates unreliability of eyewitness testimony.
Limitations
Lacks ecological validity – the participants were aware it was not a real crime.
Demand characteristics.
Social desirability.