Obtaining information from eyewitnesses : effects of retrieval support in eyewitness interviews

Abstract

In many police cases eyewitness statements are the only available evidence. Hence, whether a crime can be solved may critically depend on the statement quality. Seeking to improve the reliability of eyewitness statements, the thesis examined the effectiveness of retrieval support during the interview when the witnessing conditions were suboptimal (e.g., experience of stress during the crime), as well as retrieval support through repeated interviews. Retrieval support refers to techniques that help witnesses get access to their recollections (e.g., asking the witness to picture the incident in his/her mind). The results showed that retrieval support improves recall performance only after some suboptimal conditions. Furthermore, recall performance can be enhanced when witnesses are interviewed several times. Unfortunately, police detectives in the Netherlands are not aware of the latter, as this research has shown. Therefore, interview trainings need to be revised to improve police detectives’ knowledge about human memory.