Skip to main content

The Language of Mens Rea

Posted by on Friday, October 17, 2014 in Articles, Volume 67, Volume 67, Number 5.

The Language of Mens Rea

Appendix B: Full Text of Scenarios in the Revised MPC Definitions Experiment

Appendix B: Full Text of Scenarios in the Signal Variant and Revised Recklessness Experiments


This Article empirically tests two key questions. First: How sensitive are jurors to variations in the language that delineates the criminal mental state categories? Second: To what extent do jurors assign culpability in the manner assumed by the Model Penal Code (MPC)?

In prior work, we challenged numerous assumptions underlying the MPC mental state architecture, which divides guilty minds into four kinds: purposeful, knowing, reckless, and negligent. Our experiments showed that subjects had profound difficulty categorizing some of the mental states, particularly recklessness, in the context of scenarios in which hypothetical actors caused harmful results. And, when asked to punish hypothetical actors, subjects punished knowing behavior and reckless behavior indistinguishably.
Here, we extend our prior work in two main ways. First, we show that a person’s ability to apply the MPC mental states is susceptible to subtle variations in the language that defines and communicates them. For instance, we demonstrate that using slightly different wording can significantly improve participants’ ability to accurately identify the mental state of recklessness (notwithstanding that reckless and knowing mental states remain by far the hardest to classify). Second, we show that even when people can see the mental state distinctions that the MPC draws, they don’t necessarily rank order the mental states—by culpability level—in the order the MPC assumes.

These findings raise questions about the normative basis for the knowing/reckless distinction in the MPC’s mental state hierarchy in the context of result elements. Further, because even small changes in phrasing can produce significant differences in juror evaluation, the findings raise genuine concerns about the adequacy of MPC-based culpability instructions in criminal cases. Our results suggest the need for a critical reexamination of the substantial divide between the expectations and assumptions of drafters of criminal codes, on one hand, and empirical reality, on the other.


Matthew R. Ginther
J.D. Candidate, Vanderbilt Law School; Ph. D. Candidate in Neuroscience, Vanderbilt University.

Francis X. Shen
McKnight Land-Grant Professor & Associate Professor of Law, University of Minnesota; Executive Director of Education and Outreach, MacArthur Foundation Research Network on Law and Neuroscience.

Richard J. Bonnie
Harrison Foundation Professor of Medicine and Law, Professor of Psychiatry and Neurobehavioral Sciences, Professor of Public Policy, and Director of the Institute of Law, Psychiatry and Public Policy at the University of Virginia.

Morris B. Hoffman
District Judge, Second Judicial District (Denver), State of Colorado; Adjunct Professor of Law, University of Colorado and University of Denver; Member, John D. and Catherine T. MacArthur Foundation Research Network on Law and Neuroscience; Research Fellow, Gruter Institute for Law and Behavioral Research.

Owen D. Jones
Joe B. Wyatt Distinguished University Professor, New York Alumni Chancellor’s Professor of Law, and Professor of Biological Sciences, Vanderbilt University; Director, MacArthur Foundation Research Network on Law and Neuroscience.

René Marois
Professor, Department of Psychology and Center for Integrated and Cognitive Neuroscience, Vanderbilt University.

Kenneth W. Simons
Professor of Law and The Honorable Frank R. Kenison Distinguished Scholar in Law, Boston University School of Law.