Selecting lineup foils in eyewitness identification experiments: Experimental control and real-world simulation

Experimental research on eyewitness identification follows a standard princ iple of experimental design. Perpetrator-present and perpetrator-absent lin eups are constructed with the same foils; so that the two conditions ave id entical except for the presence or absence of the true perpetrator of the c rime. However this aspect of the design simulates conditions that no nor co rrespond to those of real criminal investigations. Specifically, these cond itions can create perp-absent lineups in which the foils are selected based on their similarity to an unknown person-the real perpetrator. Analysis of the similarity relations predicts that when foils for perp-absent lineups are selected based on their match to the perpetrator the false identificati on rate will be lower than if the foils are selected based on their match t o the innocent suspect. This prediction was confirmed ire nit experiment th at compared these two perp-absent lineup conditions These results suggest t hat false identification rates in previous experiments would have been high er if the foils had been selected based on their match to the innocent susp ect, rather than the absent perpetrator.