A Moral Foundations Approach to How Jurors Weigh Aggravating Evidence

This award is funded in whole or in part under the American Rescue Plan Act of 2021 (Public Law 117-2). Capital jurors who find a defendant guilty are subsequently tasked with making the decision on whether that person should live or die. This decision is arguably the toughest moral decision to make, and capital jurors have to make the decision and develop a justification for that decision.

It is currently unclear what goes into this decision-making process and how capital jurors weigh different evidence that involves aggravating and mitigating circumstances. Though most research to date has assumed jurors' uniform interpretation of evidence, most jurors probably weigh evidence differently based on their own values, beliefs, and experiences.

By assessing jurors'own moral beliefs and by mapping moral beliefs onto their interpretation of evidence and ultimately their death penalty recommendations, the current research provides a much more precise way of thinking about how people actually judge evidence. This research assesses both the inherent value of the evidence and the subjective value of the juror's appraisal of that evidence to better explain how and why jurors come to very different verdicts across similar cases and similar verdicts across very different cases.

This research will extend research on moral decision-making and help address and explain some of the variability in evidence evaluation in the death penalty sentencing phase of capital trials.

The current project applies moral foundations theory to mock jurors' moral evaluations of aggravating and mitigating evidence presented in death penalty trial vignettes to determine which aggravators represent more severe moral violations and subsequently impact death sentences, and if the influence of the aggravators on death sentences is contingent upon the jurors' moral beliefs and values. This is accomplished by using experimental designs and a multi-study approach to identify and isolate particular moral mechanisms triggered by the presentation of specific aggravators in the trial's sentencing phase.

Each subsequent experiment extends the prior experiment by varying aspects of the defendant, evidence, and circumstances of the crime. This project provides the first experimental test of some of the underlying assumptions of moral inferences embedded in jurors' evaluations of aggravators and mitigators. Though moral justifications underlie the use of the death penalty, a proper theoretical moral framework has yet to be applied to jurors' evaluations of evidence during the sentencing phase of a capital trial, and this project fills this gap.

Findings will be used to advance theory, and provide recommendations for attorneys and judges involved in capital trials. This project also contributes to the development of research opportunities at minority serving institutions through a collaborative research lab.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.