Backloading in the Sequential Lineup Prevents Within-Lineup Criterion Shifts That Undermine Eyewitness Identification Performance
Horry, R and Palmer, MA and Brewer, N, Backloading in the Sequential Lineup Prevents Within-Lineup Criterion Shifts That Undermine Eyewitness Identification Performance, Journal of Experimental Psychology: Applied, 18, (4) pp. 346-360. ISSN 1076-898X (2012) [Refereed Article]
Although the sequential lineup has been proposed as a means of protecting innocent suspects from
mistaken identification, little is known about the importance of various aspects of the procedure. One
potentially important detail is that witnesses should not know how many people are in the lineup.
This is sometimes achieved by backloading the lineup so that witnesses believe that the lineup
includes more photographs than it actually does. This study aimed to investigate the effect of
backloading on witness decision making. A large sample (N = 833) of community-dwelling adults
viewed a live "culprit" and then saw a target-present or target-absent sequential lineup. All lineups
included 6 individuals, but the participants were told that the lineup included 6 photographs
(nonbackloaded condition) or that the lineup included 12 or 30 photographs (backloaded conditions).
The suspect either appeared early (Position 2) or late (Position 6) in the lineup. Innocent suspects
placed in Position 6 were chosen more frequently by participants in the nonbackloaded condition
than in either backloaded condition. Additionally, when the lineup was not backloaded, foil
identification rates increased from Positions 3 to 5, suggesting a gradually shifting response
criterion. The results suggest that backloading encourages participants to adopt a more conservative
response criterion, and it reduces or eliminates the tendency for the criterion to become more lenient
over the course of the lineup. The results underscore the absolute importance of ensuring that
witnesses who view sequential lineups are unaware of the number of individuals to be seen.