A position of influence: Variation in offender identification rates by location in a lineup

Researchers have identified several threats to the validity of the use of the lineup as a test of true recognition. One concern is related to the structure of the simultaneous lineup. It is argued here that a simultaneous presentation of an array nonetheless requires the viewer to undertake sequential processing of the items in the array. This sequential pattern is unlikely to be random and therefore the position of a culprit in a lineup may have a significant effect on the accuracy of witness selection. A simulated crime (snatching of a handbag) was shown to a convenience sample of 84 undergraduates aged between 18–23 years. In 84 subsequent live lineups, the offender was placed with four foils. He was positioned on the far left (position 1) in 42 cases (50%), and in 14 cases respectively in positions 3 (centre), 4 (centre right) and 5 (extreme right). A very strong association was found between position and correct identification with position 1 placement leading to a significantly lower proportion of correct identification (7.1%) compared to position 3 (50.0%), position 4 (64.3%), and position 5 (21.4%). Steps to remedy possible positional biases are considered. Copyright © 2009 John Wiley & Sons, Ltd.