Social Psychology and Plea Bargaining: Applications, Methodology, and Theory

Two experiments with male subjects were conducted to investigate the plea bargaining process. Experiment 1 used a role-playing procedure to identify variables that affect the acceptance of a plea bargain. Eighteen percent of the subjects playing the role of innocent defendants accepted the plea bargain, whereas 83% of the guilty defendants accepted. Two other main effects revealed that defendants were more likely to accept a plea bargain when relatively many charges had been filed against them and/or when the severity of punishment upon conviction was great, although internal analyses revealed that these effects were present in guilty defendants only. Experiment 2 was conducted using involved participants to provide validation for the major result of Experiment 1. Students were made to be innocent or guilty of having prior information about an exam. All were accused of having used prior information and were given an opportunity to plea bargain rather than face an ethics committee. In accord with Experiment 1, guilty students accepted the plea bargain significantly more often than innocent students. Results are discussed in terms of information differences between innocent and guilty defendants and the availability heuristic. Implications of the data for the criminal justice system are discussed, as are limitations of the present approach and suggestions for further research on plea bargaining.