The identification of suspects by eyewitnesses is anything but a precise science. In order to account for this imprecision, courts have instituted a number of rules regulating the process by which witnesses attempt to identify perpetrators. The ultimate goal is to avoid suggestiveness: If an identification process is tainted in that regard, a court will suppress the resulting ID.
The Psychology of Eyewitness Identification
Cognitive psychologists have conducted literally thousands of experiments examining factors that might affect the accuracy of eyewitness identifications.
Lineup Procedure in Criminal Cases
Generally, live lineups don’t seem to be more likely to produce accurate identifications than showups and
Face-to-Face Eyewitness Identification: "Showups"
Showups bring suspects and witnesses or victims of a crime together in face-to-face meetings.