Can science step in and assist in Rule 403 determinations of “unfair prejudice”? When confronted with “gruesome” evidence, all too often autopsy photos or images of severe injuries, judges must assess whether there is a risk of unfair prejudice or misleading the jury and then, if the risk is present, “may” exclude the proof.¹

Yet there is no court-dictated workable metric for assessing when either risk is present beyond boilerplate terminology such as whether the “[e]vidence… makes a conviction more likely because it provokes an emotional response in the jury or otherwise tends to affect adversely the jury’s attitude toward the defendant wholly apart from its judgment as to his guilt or innocence of the crime charged.”² The standard is akin to that used to describe when material is obscene — an “I know it when I see it” approach to decision-making.³

This approach begets arbitrariness. That this is so may be seen by contrasting claims of unfair prejudice in criminal and civil cases. The default in criminal seems to be that of admissibility, demonstrated in the extreme in the 2015 Aurora, Colorado movie theater shooting trial. There, 226 prosecution witnesses were called over 34 days where the only disputed issue was sanity⁴, and testimony included a detective describing the interior of Theater 9 as “the kind of thing that nightmares are made of” and an EMT testifying that “he prayed over his friend, Jessica Ghawi [one of the 12 people killed during the shooting].”⁵ The more common occurrence is the prosecution’s presentation of multiple autopsy photos such as in Commonwealth v. Woodard, where “12 color photographs portrayed various parts of [the 2 year old’s] body… [and a] single black and white photo depicted the internal injury of [the child’s] lacerated liver…”⁶

By contrast, in civil cases the plaintiff herself/himself may be excluded where that person’s physical condition has the potential to arouse the emotions of jurors. “[A] court may exclude the plaintiff or limit [her] presence without denying due process… if her mere presence… would render the jury unable to arrive at an unbiased judgment concerning liability…. This is so because, in that situation, the court must balance the plaintiff’s due process rights with the defendant’s right to an unbiased jury trial.”⁷ This disparate treatment of cases involving money damages and cases involving liberty or even the loss of life confirms the absence of a uniform, other-than-gut-instinct, metric.

In addition to arbitrariness, a second problem is the judicial assumption that exposure to gruesome images in a courtroom in the context of trial will not be upsetting because jurors see such images elsewhere. “[T]oday’s society [sic] jurors are routinely exposed to similar materials that are equally if not more gruesome than the photographs admitted here.”⁸ Statements such as this presume that what somejurors see is actually watched by all and that all are inured to the emotional impact exposure brings. Neither conclusion has hard data to support it.

Is there a methodology to reduce arbitrariness and avoid evidence that “provokes an emotional response in the jury or otherwise tends to affect adversely the jury’s attitude toward the defendant wholly apart from its judgment…?” The suggestion here is to be cognizant of the science on how judgment is affected (if not impaired) by gruesome evidence, and then use that science in a more rigorous application of Rule 403 balancing.

Read the full article via the National Judicial College.

This article was co-written with Suzanne Mannes, Assistant Professor of Psychology at Widener University, Chester, Pennsylvania.