Emotion, Proof and Prejudice: The Cognitive Science of Gruesome Photos and Victim Impact Statements

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The current framework for sorting the probative from the prejudicial considers “emotion” to be the hallmark of unfair prejudice. Emotions elicited by evidence are thought to “inflame” the jury and “cause them to abandon their mental processes.” This inaccurate view of emotion as the enemy of rationality is problematic for evidence law. We argue for a more sophisticated and nuanced view of emotion’s role in evaluating proof and prejudice. We use two types of evidence to illustrate our argument: gruesome photos and victim impact statements.

As some scholars have noted, emotional responses to evidence are not necessarily prejudicial responses. But this observation captures only a small part of the problem with the current evidentiary framework. Emotions do not always lead to prejudice, but they can lead to prejudice in more complex and subtle ways than previously recognized. The emotions elicited by evidence affect not only the decision maker’s appraisal of the evidence, but also the process of deliberation. For example, anger toward the defendant elicited by victim impact statements may result in an inability to remain open to evidence favoring the defense, to greater certainty about the verdict, and to a desire to punish. Other emotions, such as sadness or sympathy, have other effects on the deliberative process.

Conversely, emotional responses to evidence play a role in assessing probative value, and this function of emotion receives little or no recognition in evidentiary discourse. For example, to determine whether a gruesome photo is unduly prejudicial, it is also necessary to consider whether the photo contributes any additional value to the deliberative process beyond the medical examiner’s testimony. Without accounting for the role of emotion in the reasoning process, it is difficult to examine how the medium affects the message. The value added lies in the photo’s additional persuasive power, which is closely tied to its emotional impact.

Whether the emotions evoked by evidence interfere with deliberation depends on what emotions the evidence evokes, how they affect the deliberative process, and what the deliberative process is meant to accomplish. We argue that the cognitive sciences, including psychology and neuroscience, can shed substantial light on the first and second of these questions. The third is a legal question, but one that should be informed by a more informed and realistic understanding of decisional dynamics.