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News Release 97-002

Capital Punishment Decisions Hinge on Jurors Who May Not Understand Their Task

January 14, 1997

This material is available primarily for archival purposes. Telephone numbers or other contact information may be out of date; please see current contact information at media contacts.

People called upon to sit on juries for capital crimes often do not understand the language of the law, the factors they are supposed to weigh in considering a sentence, or even that they have final responsibility for imposing punishment. New research funded by the National Science Foundation (NSF) seeks ways to improve the judgment of jurors who literally make life and death decisions.

Richard L. Wiener, a psychologist at Saint Louis University who studies how juries make decisions, has received a three-year research grant for almost $200,000 from NSF to identify the most pervasive and problematic errors jurors commit which may influence deliberations and final sentencing in first-degree murder trials.

Earlier research shows that potential jurors do not reliably comprehend instructions which direct them to weigh "aggravating" and "mitigating" factors to determine whether to sentence a defendant to life in prison or to death. Wiener says many jurors are not clear about the legal definition of these terms, and are often confused about the difference between "counting" and "weighing" these critical factors. Many misunderstand what it means to find a defendant worthy of the death penalty "beyond a reasonable doubt," he says.

Not only do many jurors not comprehend legal terms, they may not understand legal procedures.

"Some jurors may base a decision to impose the death penalty on the belief that the final responsibility of imposing a sentence rests with the judge," says Wiener; "however, punishment in first-degree murder cases is the responsibility of the jury."

In the first part of his NSF-supported research, Wiener will interview potential jurors to assess their understanding of the legal process, such basic terms as "mitigating," and what the law in their states expects of juries in capital cases. Wiener and his team of researchers will develop modifications to common court procedures to help jurors better understand their responsibilities and make decisions that are more consistent with the law.

Wiener intends next to test his innovations with potential jurors. During jury simulations, he plans to show volunteers videotapes of the guilt and penalty phases of re-enacted murder trials and allow them to arrive at their own decisions. His modifications include presenting jurors a list of common conceptual errors to avoid in court, and using a diagrammed flow chart to trace the procedural path for jury decision-making rather than relying on a traditional description in legal language.

Evaluating the resulting decisions of mock juries should "contribute to a better understanding of how to improve the present process of guiding jurors in America's courtrooms," says Harmon Hosch, who directs NSF's Law and Social Science Research Program.


Media Contacts
George Chartier, NSF, (703) 292-8070, email:

Program Contacts
Harmon Hosch, NSF, (703) 292-8762, email:

The U.S. National Science Foundation propels the nation forward by advancing fundamental research in all fields of science and engineering. NSF supports research and people by providing facilities, instruments and funding to support their ingenuity and sustain the U.S. as a global leader in research and innovation. With a fiscal year 2021 budget of $8.5 billion, NSF funds reach all 50 states through grants to nearly 2,000 colleges, universities and institutions. Each year, NSF receives more than 40,000 competitive proposals and makes about 11,000 new awards. Those awards include support for cooperative research with industry, Arctic and Antarctic research and operations, and U.S. participation in international scientific efforts.

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