Eyewitness collaboration

In the research project Eyewitness Collaboration, financed by the Society in Science in Switzerland, Dr. Annelies Vredeveldt and Prof. Peter van Koppen investigate what happens when witnesses remember together.

In the eyewitness literature, memory has been portrayed as unreliable and malleable. Further, research on discussion between witnesses has focused almost exclusively on its potential negative consequences, namely that witnesses can contaminate each other’s memory. From a practical perspective, the exclusive focus to date on harmful consequences of co-witness discussion has yielded only one recommendation for investigative interviewers: do not let witnesses talk to each other. This research project aims to shift the focus towards ways in which witnesses may be able to help each other remember more or better. For example, witnesses might help each other remember more, through a memory process known as “cross-cuing”. Moreover, they might correct each other’s errors, through a memory process known as “error pruning”.

Experiments to date show that the addition of a collaborative interview with pairs of witnesses, after initial individual interviews are completed, result in new information that is more accurate than can be obtained with repeated individual interviews. Research is currently underway to test whether these benefits are also observed in a field setting. If the benefits extend to real life, the increase in forensically relevant and accurate information as a result of collaborative eyewitness interviews could help solve criminal cases.

See also our publications about eyewitness collaboration.