Biased interpretation of evidence by mock jurors

Predecisional distortion is jurors' biased interpretation of new evidence to support whichever verdict is tentatively favored as a trial progresses. In 2 experiments, students and prospective jurors distorted evidence from a mock trial. Further, the magnitude of prospective jurors' distortion was twice that of students. Consistent with previous research, distortion increased with juror confidence in whichever verdict was currently leading. In spite of clear instructions to ignore prior beliefs, general proplaintiff or prodefendant attitudes influenced the verdicts of prospective jurors, but not of students. These findings suggest that jury instructions should warn against not only premature decisions but also any tentative judgments, lest such opinions influence jurors' evaluations of subsequent evidence. Predecisional distortion in jury trials may lead to biased outcomes resulting from evidence order effects.