In 1973, Justice Thurgood Marshall wrote in the U.S. Supreme Court ruling in Peters v. Kiff, "When any large and identifiable segment of the community is excluded from jury service, the effect is to remove from the jury room qualities of human nature and varieties of human experience, the range of which is unknown and perhaps unknowable." Since then, social psychologists have explored what happens when juries are deprived of diversity.
In a landmark 2006 study, social psychologist Samuel Sommers used a mock jury exercise to examine the processes through which racial diversity impacts group decision-making
[1]. Sommers recruited jury-eligible citizens and divided them into 29 deliberation groups. The groups were assigned to one of two conditions - a racially diverse group or an all-White group.
Jurors then watched a trial video where a Black defendant faced charges relating to sexual assault. Even before the deliberation process, members of diverse juries were nearly 10% less likely to presume guilt than the all-White juries. Furthermore, an analysis of the deliberations showed that jurors in the diverse group were more thorough when evaluating evidence. They deliberated for more time, discussed more facts about the case, made fewer factual errors, and were more open to engaging in conversation about issues of race. Sommers observed that the diverse juries did not necessarily outperform their homogenous counterparts because of Black jurors' contributions. Rather, he observed that the diversity element helped both Black and White jurors. He observed that White jurors in the diverse groups exchanged more information and considered a broader range of facts before casting a verdict than did White jurors in the all-White groups.
"They deliberated for more time, discussed more facts about the case, made fewer factual errors, and were more open to engaging in conversation about issues of race."
Similar results were observed when the discussion did not revolve around a racially charged case study such as the one seen in Sommers research. In a 2004 study, Anthony L. Antonio, Associate Professor at Stanford University, and colleagues, found that racially diverse groups that were discussing targeted social issues, such as child-labor practices in developing countries and the death penalty, engaged in more robust discussions than non-racially diverse groups [2]. They found that White jurors "demonstrated more complex thinking when assigned to a diverse group than when assigned to an all-White group." Put simply, diverse groups are more likely to have fruitful discussions.
Looking beyond the scope of racial diversity, the quality of deliberations is also observed to be enhanced with gender diversity. In a 2002 study, Nancy S. Marder, Law Professor and Director of the Justice John Paul Stevens Jury Center at Chicago-Kent College of Law, distributed a questionnaire to jurors from 26 criminal juries (including both violent and nonviolent crimes) in Los Angeles County after they had concluded their deliberations (3]. Marder observed that jurors who served on gender-diverse juries reported more thorough and longer deliberations. In contributing their different perspectives, jurors provided a greater array of ideas for group consideration, which led to more thorough deliberations.
A diverse jury panel may be beneficial as it can reduce the manifestation of a cognitive bias known as "groupthink." Groupthink occurs when cohesive decision-making groups suppress dissent or refrain from discussing contrary information to avoid disagreeing with the consensus. Psychology research on the topic has found that groupthink develops in a group when decision-making is a novel or unfamiliar experience (i.e., when jurors deliberate on issues that are unfamiliar to them) or when placed in a challenging decision-making environment that could include stress from moral dilemmas. Groupthink can negatively impact juror decision-making because biases shared by a homogenous group are more apt to be reinforced - and even amplified - as a result of like-minded group discussion [4).
As seen in the research centered on racial and gender composition, diverse jurors are more likely to engage in wide-ranging and complex discussions. Lawyers must be mindful that a more diverse jury will have more in-depth deliberations, which can be a good or bad thing, depending on your case.
While the research suggests that more diversity increases the depth and quality of jury deliberations, it is important for you to be objective about the strength of your case when de-selecting a jury. For instance, if you are representing the plaintiff and feel that you are relatively strong on the merits and have a straightforward theory of liability, then all other things being equal, a more homogenous jury is advantageous. Conversely, if you are representing a criminal defendant and (in addition to the tall odds that ordinarily confront anyone accused of a crime) you are dealing with some daunting emails or text messages, a diverse jury is your friend. As we are well aware, there is no simple answer to what ultimately influences the outcome in a group decision-making dynamic such as a jury. However, the foregoing provides yet another variable to consider as you exercise your challenges.