"Traditional arguments in favor of diversity often focus on ethics, morality and constitutionality," said Samuel R. Sommers, Ph.D., assistant professor of psychology in the School of Arts and Sciences at Tufts University. "I wanted to look at the observable effects of diversity on performance."
In a study involving 200 participants on 29 mock juries, panels of whites and blacks performed better than all-white groups by a number of measures. "Such diverse juries deliberated longer, raised more facts about the case, and conducted broader and more wide-ranging deliberations," said Sommers. "They also made fewer factual errors in discussing evidence and when errors did occur, those errors were more likely to be corrected during the discussion."
Surprisingly, this difference was primarily due to significant changes in white behavior. Whites on diverse juries cited more case facts, made fewer mistakes in recalling facts and evidence, and pointed out missing evidence more frequently than did those on all-white juries. They were also more amenable to discussing racism when in diverse groups.
Study expands traditional psychological, legal assumptions
"Traditionally, most psychologists and legal scholars have assumed that the influences of racial diversity result from the contributions of minority group members, who in effect bear the burden of bringing new perspectives and experiences to the table," said Sommers. "This study offers the novel hypothesis that majority group members are also responsible for effects of diversity, and that performance advantages to jury diversity are not limited to white and black jurors bringing different experiences to the jury room and sharing different perspectives."
The study is published in the April issue of the Journal of Personality and Social Psychology.
Sommers studied 121 individuals from a jury pool at a Michigan courthouse and 79 jury-eligible individuals recruited through newspaper advertisements. All were randomly assigned to six-person panels, most with an alternate, that were either all white or included four white and two black members.
Panels watched a 30-minute video summarizing the trial of a black defendant and white victims. Jurists were then polled in writing as to the guilt of the defendant. Half the jurists in all-white panels thought the defendant was guilty, compared with 34 percent of whites on diverse panels. "Changes in whites' behavior began as soon as they were aware of the composition of their group, before jury deliberations began," said Sommers.
The research also showed that whites were much more willing to talk about race in a diverse setting. In all-white panels, when one juror brought up race, another member would try to change the subject, minimize discussion or suggest that race was irrelevant.
Implications go beyond legal system
While the research examined the benefits of diversity in criminal juries, Sommers believes that the study has significant applications for business, higher education and other institutions that grapple with difficult or controversial issues.
"Because the study examines group decision-making in a realistic setting, the findings have potential implications for a variety of contexts--from the classroom to the boardroom, or wherever a premium is placed on fact-finding and reaching a good decision," he said. "Diverse groups show a number of advantages and benefits when it comes to this type of decision making."
Tufts University, located on three Massachusetts campuses in Boston, Medford/Somerville, and Grafton, and in Talloires, France, is recognized among the premier research universities in the United States. Tufts enjoys a global reputation for academic excellence and for the preparation of students as leaders in a wide range of professions. A growing number of innovative teaching and research initiatives span all Tufts campuses, and collaboration among the faculty and students in the undergraduate, graduate and professional programs across the university's eight schools is widely encouraged.