Polygraph Evidence and Juror Judgments: The Effects of Corroborating Evidence1


  • 1

    Portions of this study were presented at the annual meeting of the American Psychological Society, Denver, Colorado, June 1999. The authors thank Rachel Latter for her comments on an earlier version of the manuscript.

Correspondence concerning this article should be addressed to Bryan Myers who is now at Department of Psychology, Social and Behavioral Sciences Building, 601 South College Road, University of North Carolina at Wilmington, Wilmington, NC 28403. E-mail: myersb@uncw.edu


A total of 169 college freshman were presented with a mock transcript of a sexual assault trial. We varied both polygraph expert testimony indicating that the defendant was deceptive (polygraph/no polygraph) and testimony by a medical expert and eyewitness who further corroborated the defendant's guilt (corroborating evidence/no corroborating evidence). Whereas the presence of corroborating evidence influenced verdicts as well as probability of commission (PC) estimates regarding the defendant, evidence of a failed polygraph test did not significantly influence verdicts or PC estimates, nor did the presentation of polygraph evidence interact with the corroborating evidence.