Reconsidering the Relationship between Cognitive Psychology and Plea Bargaining

Abstract

Cognitive researchers have identified numerous ways in which human reasoning diverges from the rational choice model employed by mainstream economic theory and conventional law and economics. Applications of the insights of this cognitive research to the study of plea bargaining, however, gives rise to a puzzle. Most of the cognitive quirks and biases identified by researchers, such as loss aversion, overconfidence, overdiscounting, and self-serving bias suggest that defendants should be consistently disinclined to plead guilty, a prediction in stark tension with the overwhelming prevalence of plea bargaining in modern criminal practice. This Essay reconsiders the reigning explanations for plea bargaining's prevalence in light of the cognitive research, concluding that several common features of the criminal justice system are best explained precisely as mechanisms designed to overcome plea-impeding cognitive biases. A consideration of the impact of cognitive bias on plea-bargaining casts new light on the factors that drive plea-bargaining outcomes and helps to explain, among other things, the magnitude of sentencing differentials, the pervasiveness of pretrial detention, and the prosaic procedural brutality that is a universal feature of virtually every encounter with the system.

Keywords: Law and psychology, plea bargaining cognitive psychology, criminal procedure