It Must Have Been Him: Coherence Effects within the Legal System

Abstract

The present series of studies examine how jurors and public defenders evaluate different pieces of evidence and integrate them into a coherent conclusion within the context of a criminal case. Previous research has shown that in situations where both sides of the case are compelling, decision-makers nevertheless come to highly confident and polarized decisions, called coherence shifts (Simon, 2004). The present research sought to expand on coherence effects, improve upon the methodology of previous studies, and explore potential moderators of coherence. In Study 1, mock jurors (n = 306) read about a criminal case and evaluated multiple pieces of evidence at various points throughout the case. Results indicated that participants exhibited pronounced coherence shifts (i.e., their evaluations of the various pieces of evidence (a) became more consistent as the case progressed, and (b) were evaluated in line with their initial leanings) using an improved methodology that randomized evidence order and evidence valence.