[The effect of suggestibility on eyewitness identifications: A comparison between showups and lineups]

There are two types of eyewitness-identification procedures: showups and lineups. Although the false-identification rate of showups was considered to be higher than that of lineups, experimental research has not always supported the superiority of lineups. Further, suggestibility of showups is believed to produce higher false-identification rates, but no experimental study has manipulated suggestibility. In this study, we manipulated suggestibility; 258 participants performed photo identification in a showup or lineup. The results revealed that the correct-identification rate was higher in the showups than the lineups, and the rate of dangerous false identification for the innocent suspect did not differ between showups and lineups. In lineups alone, the false-identification rate of the high-suggestibility.condition was marginally higher than that of the low-suggestibility condition. The results indicate that suggestibility, which results from the preconception that the perpetrator must exist in the photos, increases false identifications in relative judgments, such as in lineups.