Purpose. Line-up administrators’ expectations have been shown to influence eyewitnesses’ identification decisions. Expectations may also influence administrators’ willingness to record witnesses’ decisions as positive identifications.
Methods. Single- and double-blind participant administrators presented a line-up to a confederate witness, who identified either the suspect or a filler.
Results. A hierarchical log-linear analysis revealed an interaction effect of blindness and witness choice on participants’ recording of the identification: Single-blind administrators were more likely to record the confederate's choice as a positive identification when the witness chose the suspect (vs. a filler), whereas double-blind administrators’ records were not influenced by the witness's choice. An interaction between blindness and witness choice also emerged for participant administrators’ witness evaluations. Single-blind administrators rated confederates who chose a filler as significantly less credible than those who chose a suspect; double-blind administrators’ ratings were consistent across photo selection.
Conclusions. Blindness influenced line-up administrators’ record of line-up outcomes. These results add to the growing body of research supporting the use of double-blind line-up administration.