Partisanship and Prosecutorial Decision Making: An Experiment

Abstract

This paper reports an experiment that simulated prosecutorial decision making. Prosecutorial decision making is of great importance since upwards of ninety percent of criminal verdicts are meted out by prosecutors. That means that prosecutors, rather than judges and juries, dispense the lion share of criminal convictions. The study was designed to examine three questions. First, the study examined the objectivity of prosecutors’ assessment of the facts of cases. A prior study (presented at CELS, 2008) demonstrated that the mere assignment of participants to adversarial roles distorts and polarizes their views of the case (as compared to one another, and vis-a-vis a neutral assignment). The current study finds that a prosecutor’s view of the case is affected also by situational variables which can be characterized partisanship. This effect is of practical importance given its influence on prosecutorial decision making, especially in the plea bargaining (process by which more than 90% of convictions are obtained), and also because the structure and incentives in DA offices often promote partisanship. Second, the study was designed to test the specific role of anger in the making of a prosecutorial decision. Normatively, judgments of culpability in such cases ought to be based entirely on a factual determination; emotions, particularly anger, ought to play no role. Research on anger has found that arousal of anger results in higher attributions of blame, perception of intentionality, lower thresholds of evidence, and dismissal of alternative explanations and mitigating circumstances. Our manipulation of partisanship resulted in greater anger towards the suspect. Mediational analysis and Structural Equation Modeling revealed that while anger mediated the effect of the assignment on the verdict and the interpretation of the facts, it was also mediated by them in return. This bi-directionality is consistent with coherence based reasoning and the underlying mechanisms of parallel constraint satisfaction. This finding also complicates the distinction between “integral” and “incidental” arousal of anger. The study was designed also with novel basic-psychological objective in mind. Specifically, it was designed to explore the underlying cognitive mechanism by which “hot” and “cold” cognitions interact. Though a considerable body of past research has demonstrated that the two types of cognition affect one another, there is scant evidence pointing to the mechanism by which this occurs. This study provides experimental support for the conclusion that hot cognitions are incorporated in coherence based reasoning, alongside cold cognitions. Both types of cognitions are driven by Gestaltian forces (specifically, parallel constraint satisfaction processing) towards a point of equilibrium, at which all cognitions involved - the assessments of the facts, overall judgments, motivation, affect, and emotions - come together at a point of maximum coherence.