Leippe, M. R. (1985). The influence of eyewitness nonidentifications on mock-jurors’ judgments of a court case. Journal of Applied Social Psychology, 15, 656-672.
Two experiments examined the effect of an eyewitness nonidentificution on mock-jurors’ verdicts in robbery cases, as well as the effects of number of identifying eyewitnesses and status of the identifying witness (victim or bystander). Subjects read court case summaries that included variable eyewitness evidence and constant alibi, circumstantial, and character evidence. In Experiment 1, frequency of guilty verdicts was significantly less when an eyewitness testified in court that the defendant was not the perpetrator, even when this nonidentification opposed two positive identifications. In Experiment 2, a low guilty rate was again associated with the presence of a nonidentifier, but only when the nonidentifier actually testified in court and stipulated that the defendant is “not the man.” On the average, 70% of the jurors delivered guilty verdicts when both the victim and bystander gave identifying testimony, whereas 12.5% delivered guilty verdicts when the bystander gave opposing nonidentifying testimony. Guilty rates were unaffected by the identifying eyewitness’ status and (in Experiment 2, but not Experiment 1) were higher when there were two (vs. one) identifying eyewitnesses. Eyewitness testimony influenced juror postdeliberation verdicts. More convictions when 2 witnesses (victim, bystander) identified the defendant compared with 1, but conviction rate much lower when bystander contradicted victim’s identification.