Computer-Assisted Lineups

Lineup Construction

Researchers at the University of Northern Iowa have developed a Web-based program that allows officers to construct a lineup in the office or in the field. Internet capability (via modem, cable, wireless, or cell phone) allows the computer to link to a central database of faces that can be searched on the basis of a description of the perpetrator. The officer can then construct the lineup. Researchers use a method to evaluate lineups in order to determine if nonsuspect lineup members are serving as adequate fillers. This is referred to as a mock witness evaluation, and it involves providing a person who is not the actual witness with a description of the suspect. The mock witness is then given a lineup and asked to pick out the suspect. If mock witnesses can pick out the suspect at a greater than chance rate, the lineup is said to be biased. Typically, the realization that a lineup is biased occurs well after the lineup administration procedure, usually at the criminal trial. However, the computerized method allows for a mock witness test to be conducted during the course of the investigation, and in the event that the lineup is biased, new lineup members can be selected, thereby avoiding biased lineups being shown to witnesses. The police can accomplish this by sending the lineup and the description of the suspect to officers not associated with the case (across the hall or the state), providing for the lineup to be evaluated prior to administering it.

Lineup Presentation

Police lineups in the United States have traditionally been administered by presenting the witness a photo array, typically arranged six photos to a page. (These are sometimes referred to as “6-packs.”) In this type of lineup, photos are presented simultaneously, and the witness chooses a photo by pointing at or stating the [Page 131]position number of the lineup member. There has been a recent movement toward administering lineups sequentially, so that witnesses see only one photo at a time. Unlike the simultaneous lineup, in which there is only one lineup decision, witnesses make a decision for each photo in the sequential lineup (“yes” or “no”). One benefit of the sequential lineup is that it has been demonstrated to reduce false identifications of innocent individuals.

Administrator Bias

An additional benefit of the sequential method is that the photos can be randomized so that the administrator does not know which photo the witness is looking at, reducing the likelihood of administrator bias. Administrator bias occurs when the administrator inadvertently gives cues to which photo belongs to the suspect. When neither the administrator nor the witness knows who the suspect is, the procedure is referred to as “double-blind” administration. Computer-assisted lineups provide for reduced interaction between administrator and witness, which greatly reduces the unintentional cues that can pass from the administrator to the witness.

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