The Effects of Likelihood of Conviction, Threatened Punishment, and Assumed Role on Mock Plea Bargaining Decisions.

This article presents a quasi-experimental study on a defendant’s decision to plead guilty based on three sources of information: the defense attorney’s advice regarding the likelihood of conviction at a trial, the sentence if the plea is accepted, and the sentence if the plea is rejected. It discusses various decision-making models (i.e., a rational decision model, a mathematically-based decision model, an optimizing strategy, and a “satificing” strategy), and hypothesizes that defendants will utilize the optimizing strategy when deciding whether to plead guilty, which involves the defendant’s consideration of several sources of information and selection of the option that leads to the greatest reward with the smallest costs. Over 400 college students were assigned the role of either a guilty or innocent defendant and provided information regarding their likelihood of conviction at trial, the sentence if they accept the plea, and the sentence if they reject the plea. The results of the experiment lent little support to the hypothesis that an optimizing strategy would be used by a defendant when deciding whether to plead guilty. Although subjects did use several sources of information provided, each source (besides one exception) was considered independently. The experiment also indicated that an innocent person may be willing to accept a plea bargain if acceptance helps them “cut their losses.”

“Analysis of the percentage of subjects accepting a plea bargain lends only limited, at best, support for the optimizing strategy. . . . Subjects did use several sources of information that were . . . considered independently. The manner in which one piece of information was used was not significantly influenced by the others.” p. 71