Effects of Jury Warnings on Perceptions of Eyewitness Credibility and Defendant Guilt

Jurors consider eyewitness confidence to judge eyewitness reliability, but verbal confidence (as obtained in practice) is inconsistently interpreted and there is no consensus about the extent to which confidence postdicts accuracy in real world circumstances. Given these caveats, jurors could receive warnings about the confidence-accuracy (CA) relationship and verbal confidence judgments. We tested the extent to which instructional warnings influence mock jurors’ perceptions of eyewitness credibility and defendant guilt. Participants read a vignette about an eyewitness’s identification decision on three lineups followed by a verbal confidence statement (low, medium, high) after each decision. Prior to rating credibility and likelihood of guilt, participants received either a non-specific warning, a warning about the CA relationship, or a warning about the CA relationship and variability in interpretations of verbal confidence. Results suggest warnings did not influence jurors’ perceptions. Moreover, jurors did not distinguish between low and medium levels of verbal eyewitness confidence.