The Effect of Police Officer Witness Versus Lay Witness Testimony on Juror Decisions

• In Event: Jurors, Evidence, and Court Decisions

Abstract

In a factorial survey administered online, 154 participants acted as mock jurors using a trial transcript. Participants read one of two trial transcripts that were identical in all regards except that the eyewitness was presented as being an off duty police officer or a layperson. The testimony given in both cases was exactly the same. Participants provided a verdict decision and a degree of certainty rating for their decision. A verdict certainty score was then calculated by multiplying the participant verdict decision (guilty = 1, not guilty = -1) by their verdict certainty rating. Therefore, larger negative scores indicate greater certainty for a not guilty verdict while larger positive scores indicate greater certainty for a guilty verdict. Results indicated that there was a significant difference in verdict certainty between conditions, F(1, 152) = 4.54, p = .04. Participants presented with the police officer witness had significantly higher verdict certainty scores than participants presented with the layperson eyewitness. This difference in verdict decision suggests that jurors’ perceptions of the eyewitness and his/her testimony vary when the eyewitness is a police officer as opposed to a layperson, even when all other aspects of the testimony are kept consistent.

Authors

• Lindsey Marie Cole, University of New Hampshire

• Ellen S. Cohn, University of New Hampshire