Psychology and the Law: Jury Compilation

by Emily Kabalin

Law and Psychology are largely intertwined. The purpose of law is to control behavior, and the purpose of psychology is to observe, explain, and predict behavior. Therefore, psychology can help to evaluate the assumptions that law makes about human behavior. Psychologists study laws by focusing on the individual, and how the individual is responsible for his or her own actions. Psychology examines the thoughts and behavior of individuals, which provide reasons for the laws to be established. It is also an important factor within the legal system, as it helps to determine whether a defendant and his lawyer may choose to go to trial or to accept a plea bargain, or whether a juvenile offender may be better off in a residential treatment facility, or whether an ethnic judge or juror will be more sympathetic to a case than a non-ethnic judge or juror. Since the inception of these fields, there has been a constant need to find a balance between the two disciplines. Even with empirical proof, this balance is sometimes difficult to achieve.

In the late 1970s, Michael J. Saks, a psychologist and law professor, conducted a study in which he observed the differences between a large jury and a small jury and the effect that the number of jurors had on the discussion and verdict. During the study, he created two juries, one with six members and another with twelve members, showed each jury a videotaped trial, and then asked them to deliberate and present a final verdict. Saks then observed the process of the group decision-making and the product of their debates. The study found more benefits associated with the larger group of jurors, in terms of sentencing. In the small jury, the individual members participated equally in the discussion, worked cooperatively and cohesively, and found the discussion to be satisfying. However, in the large jury, the members had heated debates, made more consistent decisions, and recalled significantly more evidence from the trial video. Saks concluded that, in criminal cases, as juries grow smaller they will make more errors in acquitting guilty defendants and convicting innocent ones. In civil cases, smaller juries are inconsistent and unpredictable in their verdicts despite the similarity among cases. Later data determined that a large jury is more likely than a small jury to contain members of minority groups. Studies have also shown that groups of people with different abilities, personalities, backgrounds, and experiences are better problem solvers and critical thinkers than are groups made up of similar people who share a common background and perspective. Heterogeneous juries are more likely to evaluate data from different points of view and to have better discussions than are homogeneous juries. Juries of mixed races have many advantages over all-white juries, and they typically have longer and more thorough discussions and are more likely to discuss racially charged topics. Juries that are representative and diverse are more thorough and accurate in fact-finding and in discussions, which leads to more proper and consistent verdicts.

Despite over 600 years of common law tradition and 200 years of constitutional decisions holding that juries must consist of twelve people, the Supreme Court in the 1970s reversed its decision, claiming that the Constitution did not explicitly require juries to be comprised of exactly twelve members. The Court declared that if the behavior of smaller juries equaled that of larger juries, then they served the same purpose and were equally constitutional. With limited research and empirical data, the Court then decided that juries of six would perform equally as well as juries of twelve, thus causing many federal and state courts to reduce the size of their juries. Because the Supreme Court lacked empirical data around which it framed its decision, the holding could only be questioned and tested by empirical psychological data on jury behavior.

As shown by Michael J. Saks’ study, the Supreme Court’s decision was clearly flawed. In response to this, other government organizations presented this research as cited proof to stop the Court from condensing juries even further. It was not until the Georgia criminal courts reduced their juries to five members that the Supreme Court finally halted the reduction and decided that juries of less than six members was unconstitutional. Some of the other states simply refused any action to reduce their juries, as they believed that the empirical research showing the negative effects of smaller juries was unarguable. Also, the Committee on Federal Civil Rules attempted to combat the Supreme Court’s decision by trying to restore federal civil juries to the traditional twelve members.3 Similarly, the United States Department of Health and Human Services attempted to manipulate the predictability of jury awards in medical malpractice cases by mandating that states use juries no smaller than twelve members for malpractice lawsuits. The Supreme Court, despite these retributions, has yet to reverse the decision and re-establish the traditional constitutional minimum number of jurors at twelve. If or when the Supreme Court reverses their decision, the balance we must maintain between the law and psychology will be closer to restoration.