Eyewitness Science and the Call for Double-Blind Lineup Administration

Abstract

For several decades, social scientists have investigated variables that can influence the accuracy of eyewitnesses’ identifications. This research has been fruitful and led to many recommendations to improve lineup procedures. Arguably, the most crucial reform social scientists advocate is double-blind lineup administration: lineups should be administered by a person who does not know the identity of the suspect. In this paper, we briefly review the classic research on expectancy effects that underlies this procedural recommendation. Then, we discuss the eyewitness research, illustrating three routes by which lineup administrators’ expectations can bias eyewitness identification evidence: effects on eyewitnesses’ identification decisions, effects on eyewitnesses’ identification confidence, and effects on administrator records of the lineup procedure. Finally, we discuss the extent to which double-blind lineup administration has been adopted among police jurisdictions in the United States and address common concerns about implementing a double-blind standard.