Individual differences in eyewitness identification accuracy between sequential and simultaneous line-ups: consequences for police practice and jury decisions

Background 

Although previous research has indicated that sequential line-up procedures result in fewer mistaken identifications, this was found to be at the expense of accurate identifications more typical within simultaneous procedures. Hence, there remains a lack of agreement about which procedure is superior, and the interaction such procedures have with eyewitness confidence. The interaction between witness demographics and identification accuracy also remains unclear. participants and procedure The opportunistic sample, consisting of 60 people from the general population, was divided randomly into two experimental conditions: Simultaneous (SIM) and sequential (SEQ). Participants in the sequential procedure observed 12 photographs, one at a time, deciding if they believed the suspect to be the person shown in the current photograph and unable to return to a given picture once they decided the individual shown was not the suspect described. Participants in the simultaneous condition were shown all 12 photographs concurrently and asked to determine which, if any, of the photographs was the suspect described. results No significant differences were found in identification accuracy between line-up procedures, but significant differences in confidence levels between the two line-up procedures were found. Additionally, analysis of demographic features showed previous line-up experience to be significantly associated with identification accuracy. conclusions The present research provides new insight into the interaction of eyewitness confidence between line-up techniques, offering an alternative explanation of witness confidence as well as procedural fairness. Evidence of practice effects increasing the accuracy of identification provides beneficial future implications for police line-up procedures and safer jury decisions, often reliant on identification evidence.