Enhancing individual and collaborative eyewitness memory with category clustering recall.

Most crimes have multiple eyewitnesses. The police typically interview co-witnesses separately. In time-sensitive investigations, this could slow down evidence accumulation. Having co-witnesses collaboratively recall a crime could potentially expedite evidence accumulation. However, past research shows that collaborative group members often have conflicting retrieval strategies that disrupt each other, degrading overall recall. This cost could potentially be overcome by aligning group members' retrieval strategies with category clustering recall (CCR), which is a retrieval strategy where information is recalled from a series of forensically relevant categories (e.g., recalling the protagonists' appearance, then actions). This study examined the costs and benefits of collaborative eyewitness memory by having collaborative pairs of strangers, nominal pairs (i.e., two individuals whose recall is pooled) and lone individuals watch a crime and recall it using free recall or CCR. The collaborative pairs recalled the crime faster than the nominal pairs. They also recalled more correct information than individuals but less than nominal pairs, irrespective of the retrieval method. There is therefore a speed-recall completeness trade-off when collaborative groups recall crimes. Importantly, all participants recalled more correct information when using CCR. This provides initial evidence suggesting that CCR is superior to free recall. Further research examining CCR's benefits is recommended.