Factors Affecting False Guilty Pleas in a Mock Plea Bargaining Scenario

Innocent defendants often plead guilty to crimes they did not commit. Numerous legal and psychological factors impact their decision. “Trial penalties”—extreme mandatory-minimum sentences resulting from trial conviction as punishment for refusing to accept relatively-lighter plea deals—are the primary mechanism by which prosecutors implicitly compel false guilty pleas. As explained by the “Shadow of Trial” model, a defendant’s perceived likelihood of conviction at trial and the value they place upon a discounted sentence weigh heavily upon their decision. Because of their positions of trust, defense attorneys may also urge defendants toward a particular decision. The researchers explored these phenomena through an experimental study of 460 introductory psychology students at a Midwestern university. Each participant played the role of an innocent defendant falsely accused of cocaine trafficking and was randomly assigned to trial-penalty, conviction-probability, and attorney-recommendation conditions. The results supported the researchers’ hypothesis that harsher trial penalties in the form of severe mandatory minimum sentences create a greater risk of false guilty pleas than less-costly trial penalties that allow for judicial discretion. The results also supported the researchers’ prediction that greater likelihood of conviction would induce false guilty pleas; those participants assigned a ninety-percent likelihood of conviction were much more likely to falsely plead guilty than those assigned fifty-percent and ten-percent likelihoods. Defense attorneys’ recommendation did not have any effect here. Women were more likely than men to falsely plead guilty, tending to perceive that the case against them was stronger.

“Our findings suggest that a severe, rigid trial penalty is more likely to compel an innocent defendant to plead guilty than a less severe trial penalty, providing some evidence of the feared mechanisms underlying false guilty pleas that past research has failed to definitively uncover. Furthermore, our research replicated the findings of previous studies illustrating that innocent defendants can be impacted by the perceived likelihood of conviction at trial, with more false guilty pleas as the likelihood of conviction increases.” p. 65