[Special Feature: 10 Years of the Lay Judge System] The Lay Judge System from a Psychological Perspective

Ten years have passed since the start of lay judge trials. I am a cognitive psychology researcher studying human memory and thought, but even before the laws regarding lay judge trials were established, I was interested in the thinking and judgment processes of ordinary citizens participating in trials, and I have conducted empirical research from a cognitive psychological perspective. In this article, I would like to discuss what psychology can say about the following two issues in order to improve the lay judge system.

The first issue is whether the judgments of lay judges are inappropriately influenced by emotions. Humans are creatures easily influenced by emotions and moods, and trials often involve interactions accompanied by strong emotions. It would be unacceptable for a lay judge driven by emotion to make an irrational judgment because of it.

The second issue relates to the habits of human thinking revealed by cognitive psychological research. It is known that when humans hold a certain hypothesis, they tend to seek evidence that supports the hypothesis and ignore or overlook evidence that contradicts it (known as confirmation bias). I want to consider whether such things occur when lay judges make judgments, based on the results of psychological examinations. Finally, in connection with these issues, I would like to consider what psychological research can do to make the lay judge system better.

"I let my anger get the better of me and said something terrible to a friend. Now that my anger has subsided, I think my words and actions were inappropriate and I deeply regret it." It is easy to imagine such a situation occurring in daily life. Could the same thing happen in the judgments of lay judges? "Out of anger toward the defendant, I imposed an excessively heavy punishment. Now that my anger has subsided, I think the judgment was inappropriate and I regret it." If such a thing were to happen, it would be unfortunate for both the defendant and the lay judge themselves.

If one of the purposes of the lay judge system is to reflect the sensibilities of citizens in the judiciary, some might argue that it is not necessarily inappropriate for the emotions of lay judges to be reflected in the verdict to some extent. I often hear such opinions. However, while this way of thinking may have some merit regarding sentencing decisions, it can be said that it does not apply at all to the determination of guilt or innocence. No matter how strong the anger toward the perpetrator is, it has nothing to do with whether the defendant is the perpetrator.

Our research group has focused on this issue and, taking victim impact statements as one factor that stirs the emotions of lay judges, we have experimentally examined their influence on lay judges' determinations of guilt or innocence*1. Victims and their bereaved families are permitted to state their opinions in court regarding how much damage they have suffered due to the crime. These victim impact statements serve as a place for victims to vent their emotions regarding the crime and the perpetrator, and can sometimes sway the emotions of those listening. Although the magnitude of the damage and the strength of the victim's feelings of victimization are unrelated to whether the defendant is the perpetrator, it is possible that lay judges, exposed to victim impact statements, may have their emotions such as anger stirred and come to believe the defendant is the perpetrator.

To empirically examine this possibility, our group conducted an experiment in which mock lay judges were shown a summary of a trial and asked to judge the guilt or innocence of the defendant. The trial summary used was based on a case where a young woman, a complete stranger, was allegedly stabbed to death by a defendant who wanted to go to prison because he was ill, had no job, and could not support himself. There was no decisive evidence presented, and it could not be determined from the evidence whether the defendant was the perpetrator or not. This trial summary was presented along with a victim impact statement from the bereaved family, expressing sadness and anger over a blameless victim having her hopeful future unreasonably stolen and wishing for the defendant to be severely punished, and mock lay judges were asked to make a judgment of guilt or innocence. As a result, the percentage of those who handed down a guilty verdict was significantly higher than those who judged without being exposed to the impact statement. Furthermore, when exposed to the impact statement, mock lay judges often felt emotions such as anger, disgust, fear, and anxiety, and it was shown that those who felt these emotions had a stronger tendency to make a guilty judgment.

The results of this research indicate that interactions in the courtroom that stir emotions make lay judges emotional, and as a result, influence the determination of guilt or innocence, which should inherently be unrelated. Lay judges themselves are aware that they should avoid emotional judgments, and they may become wary when prosecutors or lawyers intentionally act in a way that fans their emotions. However, it is generally difficult to suppress emotions in many cases, and it is thought necessary to devise ways to avoid presenting information that unnecessarily fans emotions in trials.

Both lay judges and professional judges are required to evaluate evidence presented in court without holding a specific hypothesis in advance. They are then required to make a judgment on guilt, innocence, and sentencing after all evidence has been presented and the examination of evidence is completed. However, professional judges work in an environment where 99.8% of cases prosecuted over many years result in a guilty verdict, so it may be difficult for them to approach a trial without the hypothesis that "the defendant is guilty." In contrast, lay judges do not live in an environment where almost all criminal trials result in a guilty verdict, and as long as they participate as lay judges, they are thought to have a strong desire to make a fair judgment.

Can we then say that lay judges are unlikely to prematurely hold hypotheses such as the defendant being guilty or innocent, and therefore unlikely to be caught in confirmation bias? In reality, it is not only the environment of being exposed only to guilty verdicts as mentioned above that brings about hypotheses regarding guilt or innocence; there are many factors that cause lay judges to hold hypotheses, such as media reports and prejudice against specific groups or certain types of people. Our research group experimentally tested whether the opinions of other lay judges during interim deliberations cause a lay judge to hold a hypothesis about the defendant's guilt or innocence, and whether that influences the evaluation of evidence and the judgment of guilt or innocence*2.

Interim deliberations refer to discussions held by lay judges and professional judges during the course of a trial that takes place over several days, for purposes such as organizing the evidence and points of contention up to that point or exchanging opinions at that time. It is possible that exposure to the opinions of other lay judges or professional judges here could cause a lay judge to hold a hypothesis, influence the evaluation of evidence, and further influence the determination of guilt or innocence. In our experiment, we presented a trial summary of a case where a young man snatched an elderly woman's bag on the street and injured her in the process. The defendant claimed that he was mistaken for the perpetrator when he happened to pass by after the perpetrator fled into a shopping district and the pursuer lost sight of him; he claimed he was not the perpetrator. There was no decisive evidence, making it a case where it is difficult to judge guilt or innocence from the evidence. At the stage where several pieces of evidence had been shown, the opinions of other lay judges regarding specific evidence that had appeared up to then were presented as having been discussed in interim deliberations, according to the following four conditions.

(1) Both opinions presented condition: Both the opinion that the defendant is the perpetrator and the opinion that he is not are presented; (2) Guilty opinion condition: The opinion that the defendant is the perpetrator is presented; (3) Not guilty opinion condition: The opinion that the defendant is not the perpetrator is presented; (4) No interim deliberation condition: No opinions are presented. When asked about the probability of the defendant being the perpetrator at the time the interim deliberation opinions were presented, it was shown that presenting a guilty opinion led to a higher estimate of the probability of being the perpetrator, while presenting a not guilty opinion led to a lower estimate. Furthermore, the estimate of the probability of the defendant being the perpetrator at this point influenced the evaluation of evidence shown later; those who evaluated the probability of being the perpetrator as higher tended to evaluate evidence favoring guilt more highly and evidence favoring innocence lower, and further showed a tendency to ultimately hand down a guilty judgment.

The results of this experiment suggest that exposure to the opinions of other lay judges during the trial encourages lay judges to hold a hypothesis at an early stage, which causes bias in the evaluation and selection of evidence, and influences the determination of guilt or innocence, showing that lay judges may also be caught in confirmation bias.

Based on the research introduced above, let us consider what proposals are possible from psychology to make the lay judge system better. Regarding the first issue—that information stirring emotions presented in court influences lay judges' determinations of guilt or innocence—the first thing that can be considered is to keep the presentation of information that stirs human emotions to the necessary minimum. In fact, following this line of thought, attempts have been made, for example, to show monochrome photos or illustrations instead of color photos when presenting photos of a victim's stab wounds as evidence. While there seem to be legal arguments regarding such measures, it can be said that psychological research shows that such methods have a rational meaning.

The research results regarding victim (bereaved family) impact statements discussed in this article relate to a debate called procedural bifurcation. In a criminal trial, it is determined whether the defendant is guilty or innocent, and if found guilty, what kind of sentence the defendant should be given. In the current lay judge system, after all information such as evidence to be addressed in the trial—both related to guilt/innocence and related to sentencing—is presented and examined in court, lay judges and professional judges hold a discussion called a deliberation to decide on guilt/innocence and sentencing. Among the evidence shown in a trial, there is information that may be used when deciding the sentence after guilt has been determined, but must not be used when deciding guilt or innocence. Victim opinions are such information. Can lay judges make a determination of guilt or innocence while ignoring information they have already been exposed to that cannot be used for that determination? The results of our research introduced earlier empirically demonstrated that lay judges are unable to separate and use information for deciding guilt/innocence and information that can only be used for sentencing, and that there is a high possibility that the determination of guilt or innocence will be influenced by information that should not inherently influence it.

To address such issues, there is a debate called procedural bifurcation, which argues that the procedure for determining guilt/innocence and the procedure for determining the sentence should be separated. This suggests a form where, at the stage where only evidence related to guilt/innocence has been examined in court, professional judges and lay judges first make a determination of guilt or innocence, and only if found guilty, the court is opened again to examine evidence for sentencing and proceed to the determination of the sentence. Separation of trial procedures has been incorporated into the trial systems of many countries, and while some legal scholars and judges argue that it should be introduced in Japan as well, others argue that the current method is sufficient if lay judges are firmly cautioned, and that the flow of the trial should not be made complicated.

Findings from empirical research through psychological experiments can provide important and useful material for legal discussions on such issues. The research introduced earlier showed that victim impact statements from bereaved families, which are unrelated to the defendant's guilt or innocence, increase the guilty judgments of mock lay judges. Another experimental study showed that the caution that the opinions of bereaved families are unrelated to guilt or innocence and should not be used for the determination of guilt or innocence is not necessarily effective. Such findings are facts that cannot be ignored when discussing procedural bifurcation.

The second study dealing with interim deliberations can also be said to provide useful material for discussions on how interim deliberations should be conducted. Psychological empirical research on lay judge judgments is sometimes criticized for lacking reality because it asks for judgments while "pretending to be a lay judge," but it reflects the characteristics of human judgment. However, it seems that voices from psychology have not yet reached the discussions surrounding the lay judge system. I sincerely hope that psychological research on lay judge judgments will become more useful for real-world problems, and I intend to continue my efforts toward that end.

*1 See Yuji Itoh, "Psychology of Lay Judge Judgments: Approaching from Psychological Experiments" (Keio University Mita Philosophy Society, 2019). This book addresses many of the issues discussed in this article.

*2 Yuji Itoh, Hikari Tokunaga, and Hiromi Ujiie (Unpublished).