Public Release:  'Jury Decision Making: The State of the Science'

Indiana University-Purdue University Indianapolis School of Science

(INDIANPOLIS) A new book by a psychology professor in the School of Science at IUPUI uses scientific research and a healthy dose of reality to form a new theory about how juries historically have reached decisions in jury trials.

Dennis Devine, Ph.D., and an associate professor in the Department of Psychology, has spent more than a decade researching the behavior of juries. His new book, "Jury Decision Making: The State of the Science," introduces a new, integrative model of the jury decision-making process that delivers the science behind this pillar of the legal system.

"There really is no other book that does this," said Devine, who specializes in industrial and organizational psychology at IUPUI.

"I didn't want to look at one jury and analyze how it made a decision," he added. "This book attempts to move this field forward and hopefully become an authoritative resource on this topic."

He examined several hundred published studies on juries conducted since the 1950s. Past research has analyzed everything from the impact of bias at the individual level to how juries are influenced during the deliberation process.

Devine's Integrative Multi-level Theory attempts to fill the gaps left by past theories about this complex and evolving process. The new theory could have considerable impact on understanding jury behavior because it is meant to apply broadly across the estimated 150,000 jury trials each year, he said.

The multi-level theory integrates decision making on two levels: the individual juror and the jury as a whole. Each level corresponds with a distinct model of decision making within the larger theory. The final product of the juror-level model serves as the starting point for the jury-level model.

Past research has produced many well-known models about the jury process. For example, the Story Model proposes jurors base their decision or verdict on a chronological narrative they create from the evidence, and these stories often vary across jurors because of their different backgrounds. The Social Decision Scheme model examines the influence of initial jury votes on how people are swayed to join the majority opinion.

In his integrative theory, Devine explores the "Director's Cut" model for individual jurors, in which jurors create an "edited" version of the facts of each case by what is the most satisfying and plausible. The jury, on the other hand, utilizes a "Story Sampling" model, in which jurors enter deliberations with their personal stories and then share them with each other. Other jurors, the individual's participation in the deliberation discussion and the personal characteristics of the juror influence the final narrative from which a verdict is made.

"Currently, there are some real disconnects between the legal system and the scientific research," Devine said. "Attorneys value precedent and rationale. This book comes from a scholarly perspective, where we attempt to learn something from the systematic collection of data and use it to better understand this process and improve it in the future."

Devine said the book will appeal to academics who study and teach about juries and "progressive-minded judges and attorneys who might ask 'I wonder what science has to say about this.'"

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The School of Science is committed to excellence in teaching, research and service in the biological, physical, behavioral and mathematical sciences. The School is dedicated to being a leading resource for interdisciplinary research and science education in support of Indiana's effort to expand and diversify its economy. For more information, visit www.science.iupui.edu.

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