title: A problem with double-blind photospread procedures: photospread administrators use one eyewitness's confidence to influence the identification of another eyewitness.
abstract: In Experiment 1, photospread administrators (PAs, N = 50) showed a target-absent photospread to a confederate eyewitness (CW), who was randomly assigned to identify one photo with either high or low confidence. PAs subsequently administered the same target-absent photospread to participant eyewitnesses (PWs, N = 50), all of whom had viewed a live staged crime 1 week earlier. CWs were rated by the PAs as significantly more confident in the high-confidence condition versus low-confidence condition. More importantly, the confidence of the CW affected the identification decision of the PW. In the low-confidence condition, the photo identified by the CW was identified by the PW significantly more than the other photos; there was no significant difference in photo choice in the high-confidence condition. In spite of the obvious influence exerted in the low-confidence condition, observers were not able to detect bias in the photospread procedures. A second experiment was conducted to test a post-hoc explanation for the results of Experiment 1: PAs exerted influence in the low-confidence condition because they perceived the task as more difficult for the eyewitness than in the high-confidence condition. Independent observers (N = 84) rated the difficulty of the confederate's task as higher in the low-confidence condition compared with the high-confidence condition, suggesting that expectations of task difficulty might be driving the effect observed in Experiment 1. Results support recommendations for double-blind photospreads and emphasize that the same investigator should not administer photo lineups to multiple eyewitnesses in an investigation.
authors.affiliation: Psychology Department, Bates College, Lewiston, Maine, 04240, USA. abradfie@bates.edu
authors.forename: Amy Bradfield
authors.initials: AB
authors.lastname: Douglass
authors.forename: Caroline
authors.initials: C
authors.lastname: Smith
authors.forename: Rebecca
authors.initials: R
authors.lastname: Fraser-Thill
mesh_terms: D002755:Choice Behavior; D003415:Crime / Q000331:legislation & jurisprudence*; D006801:Humans; D021641:Recognition, Psychology; D014481:United States; D014743:Videotape Recording; D014796:Visual Perception