A recipe for bias: an empirical look at the interplay between institutional incentives and bounded rationality in prosecutorial decision making.

• Author: O'Brien, Barbara

1. Introduction II. The Prosecutor's Conflicting Roles A. The Dangers of Overzealous Advocacy B. Why the Duty to Advocate Can Trump Justice Obligations C. An Illustration: The Central Park Jogger Case III. Psychological Implications of Systems of Accountability A. Psychological Research on the Effects of Accountability B. Features of the Prosecutor's Job as a System of Accountability IV. Empirical Evidence of the Effects of Accountability on Legal Decision Making A. Procedures and Materials B. Measures 1. Study 1 a. Methods and Participants b. Results 2. Study 2 a. Methods and Participants b. Results C. Discussion and Limitations of These Studies: Do These Findings Generalize to Prosecutors? V. Implications for Reform A. Discovery Obligations and Dilemmas B. Cooperating Witnesses and the Risk of Perjury C. Investigatory Decision Making and Tunnel Vision VI. Conclusion APPENDIX Table 1 Table 2 I. INTRODUCTION

   Prosecutors wield tremendous power, which is kept in check by a set of unique ethical obligations. (2) They must prosecute offenders and do so with vigor. At the same time, they must serve as ministers of justice charged with considering the interests of the very defendants they prosecute. (3) In this Article, I argue that these "dual roles" (4) place demands on prosecutors that are untenable from a psychological perspective. Specifically, I apply the lessons of cognitive science to offer a comprehensive approach to identifying the ways in which prosecutors' distinctive institutional environment may undermine not just their willingness to play fair but also their ability to do so. This approach bridges prevailing schools of thought about the misuse of prosecutorial power, allowing for more nuanced predictions as to when prosecutors are most likely to transgress.

   Striking the proper balance between advocacy and justice obligations can be difficult, and prosecutors sometimes fall short. (5) In Part II, I discuss the problems that arise when a prosecutor's duty to advocate conflicts with the duty to serve justice and review the prevailing explanations for why advocacy goals sometimes triumph in these situations. In studying instances where prosecutors fail to honor their dual and arguably divergent obligations, many scholars focus on institutional incentives that foster misconduct. (6) These scholars lament an incentive structure that encourages prosecutors to seek convictions at all costs as well as the lack of effective sanctions to deter misconduct. (7) This approach implicitly treats the prosecutor as a rational actor who bases the decision to comply with a rule on an economic assessment of the expected costs and benefits of doing so.

   A second school of thought focuses on bounded human rationality. Cognitive science teaches that human beings share certain cognitive tendencies that cause them to deviate in systematic and predictable ways from purely rational information processing and decision making. (8) Scholars in this school draw on these teachings to argue that prosecutors fail to honor their multiple obligations not for sinister and calculating motives but because they labor under the same self-serving biases (9) and limitations that all humans do. (10)

   In Part III, I seek to synthesize the insights of both camps into one comprehensive view. Thus, I apply what cognitive research tells us about the general limits of human cognition to the prosecutor's unique institutional environment. To that end, I focus on accountability as an institutional feature with implications for prosecutorial decision making. I review the substantial body of psychological research exploring the ways in which different systems of accountability affect people's ability to process information in a thorough and evenhanded way. (12) This research generates testable predictions about how specific features of the criminal justice system can undermine prosecutors' objectivity. In particular, psychologists have found that when people must justify a decision to which they have already committed, they tend to engage in "defensive bolstering"--holding fast to that position even in the face of contrary evidence. (13) Thus, a system that rewards people for their ability to persuade others diminishes their willingness to acknowledge weaknesses in their arguments. The prosecutor's role as an advocate who must carry the highest evidentiary burden of proof imposes precisely this form of accountability and therefore fosters defensive bolstering.

   In Part IV, I present the results of two experiments supporting this hypothesis. In both studies, people reviewed a homicide file with the expectation that they would be judged for their performance on certain tasks. The criteria by which participants expected to be judged varied depending on the experimental condition to which they were assigned; that is, participants were randomly assigned to review the case under a particular system of accountability. Those who expected to be judged for their ability to make a persuasive case against a suspect viewed the evidence against that suspect as more compelling than did participants in other conditions. In other words, the task of building a case to persuade others colored how they personally viewed the evidence.

   In Part V, I discuss the implications of this research for reform. For many aspects of the prosecutor's job--namely, those related to the duty to advocate zealously--a one-sided view of the evidence presents no problem and may even enhance performance. (14) But when prosecutors are called upon to step out of the role of zealous advocate and instead to concern themselves with justice, these tendencies can undermine their ability to do so. I identify the situations that are likely to put prosecutors in this difficult position and argue that it is unrealistic to expect them to shift psychological gears gracefully to honor their dual roles.

2. THE PROSECUTOR'S CONFLICTING ROLES

   An observer of the American trial system could easily conclude that the prosecutor operates at a disadvantage. (15) At trial, the prosecutor shoulders the burden of proving the defendant guilty beyond a reasonable doubt. The prosecutor may not ask the defendant--often the person with the most relevant information--any questions to dispute or substantiate the charges unless the defendant chooses to testify. The prosecutor gets only one shot at victory; a not-guilty verdict bars retrial. And when the prosecutor does manage to meet the high burden of proof to secure a guilty verdict, the defendant may still appeal, seeking a new trial or outright reversal. Moreover, some judges may cut the defense leeway on close evidentiary matters rather than risk reversal on appeal should the defendant lose. (16)

   The rules that govern trial, however, give only part of the picture. Prosecutors enjoy certain advantages from the inception of a case. They are vested with substantial and virtually unreviewable discretion in deciding whom to charge and with what offenses. (17) They also enjoy an effective monopoly on fact-finding through their relationship with police. (18) These advantages have significant practical implications, as very few cases reach trial but are instead resolved by guilty pleas. Thus, much of the system's adjudication of guilt occurs outside the transparency of an adversarial trial. (19)

   In light of this considerable power, the prosecution's primary duty "is not that it shall win a case, but that justice shall be done." (20) But precisely how an individual prosecutor can be both an effective adversary and a servant of justice is unclear and the subject of much scholarly interest. (21) In some situations, these goals will be at odds. A prosecutor who suspects that defense counsel is incompetent, for example, should arguably intervene to protect the rights of the defendant and ensure a fair trial, even though doing so could make it harder to convict that defendant--someone the prosecutor believes is guilty notwithstanding counsel's shortcomings. (22) A prosecutor's duty to litigate zealously can therefore be difficult to reconcile with the general exhortation to proceed fairly, and few formal rules exist to guide that process. (23)

   1. The Dangers of Overzealous Advocacy

      Prosecutorial misconduct can occur in many forms, both on and off the record. (24) More transparent transgressions occur when prosecutors offer inappropriate opening statements (25) or inflammatory closing arguments (26) at trial. As for behind-the-scenes offenses, prosecutors have been accused of coercing witnesses, (27) knowingly or recklessly offering perjured testimony, (28) over charging defendants to extract a guilty plea, (29) and failing to disclose exculpatory information to the defense. (30)

      Not everyone agrees on the precise scope of prosecutors' duty to play fair (31) or on the frequency and pervasiveness of their failure to do so. (32) But some evidence suggests that misconduct is not a mere aberration, (33) as some have argued. (34) And even if the vast majority of prosecutors do behave scrupulously, relatively rare instances of misconduct can have devastating consequences, as illustrated most forcefully by instances of prosecutorial misconduct in wrongful convictions. (35)

      Focusing on prosecutorial misconduct, however, tells us only part of the story about prosecutors' willingness and ability to comply with the duty to administer justice. Prosecutors exercise their discretion in ways that are both well intentioned and within the law but that nevertheless profoundly affect the accuracy and fairness of the system. (36) False convictions--the most dramatic examples of the system's failure--often involve honest mistakes by ethical investigators and prosecutors. (37) Defendants rarely have the resources to conduct comparable investigations and may be limited in their access to the information that the government has collected. (38) Ideally, prosecutors offer a fresh pair of eyes to review...