Evaluation and integration of eyewitness reports

This study examined how mock jurors assess eyewitness credibility and integrate these assessments with judgments of probative value in simple, corroborating, contradicting, and facilitating inference structures. Subjects listened to an audiotape of a fictional, theft trial. In Experiment 1, contrary to prior research, amount of detail in the target witness's testimony did not influence perceived credibility. In addition, a normative Bayesian rule poorly described subjects' integration of the evidence. A rule that combinedp(event/guilt)weighted by credibility better described the judgments. Experiment 2 was designed to identify variables that affect credibility, given that amount of detail did not. Perceived credibility of the target witness was affected by the credibility of a second witness, and the nature of the effect depended upon the type of inference structure., The results of Experiment 3 suggest that an additive version of the decision rule describes judgments of guilt better than an averaging version.This article is based upon a doctoral dissertation submitted to Indiana University. I would like to thank my advisor, N. John Castellan, Jr., and the other committee members: Igor Gavanski, Margaret J. Intons-Peterson, and Steven J. Sherman. I also wish to thank Janet Magnuson for serving as legal advisor; Kelvin Bartel, Todd Dukes, Justin English, Katherine Harmening, Diana Heise, Nancy Lightfoot, Brigette Oliver, Chris, Reintz, Doug Smith, and Julie York for helping to prepare audiotapes; Tamara Levinson and Sandra Vitous for helping with data collection; and two anonymous reviewers for providing useful comments on an earlier version of this paper.