The Pivotal Voter Effect: Jurors and members of other decision-making groups are motivated to be decisive

Does the potential for indecision skew group decision making? Our research finds that pivotal voters (i.e., voters who can either “tip” their group into a decision or not) are biased to vote for options that result in conclusive (vs. inconclusive) group decisions independent of how they might have voted as a non-pivotal voter, of pressures to conform, and of reaching unanimity. Using rich field data from Louisiana court cases, we find sharp discontinuities in juries’ voting distributions at thresholds for indecision (i.e., for conviction/acquittal vs. hung juries; Study 1). In controlled lab experiments, we find equivalent discontinuities in a third-party punishment paradigm (Study 2) and in an incentive-compatible group trivia paradigm (Study 3). We find the effect is primarily driven by social forces and may function on an individual cognitive level. These findings inform how to better structure group decision making systems to ensure outcomes reflect individual group members’ beliefs.