Criminal and personal injury defense lawyers, pencils ready. Next time you ask a judge to keep gory pictures and other disturbing material out of evidence, cite David Bright. "Jurors presented with gruesome evidence, such as descriptions or images of torture and mutilation, are up to five times more likely to convict a defendant than jurors not privy to such evidence," a recent press release about his work says. The research in question isn't brand new; Mr. Bright's most recent papers are from 2006 and 2004. But he recently presented a seminar on his work in his native Australia (you can listen to the audio and see a syllabus here) — and the University of New South Wales, where he is a Ph.D. candidate, used the occasion to issue the press release recapping his recent work. Be glad they did. With his colleague Jane Goodman-Delahunty, Mr. Bright has spent the last five years exploring the effect of gruesome evidence on juries.
Pictures or no pictures
The research Mr. Bright describes in his 2006 paper — "Gruesome Evidence and Emotion: Anger, Blame, and Jury Decision-making," in volume 30 of Law and Human Behavior — is a straight-up comparison. Just over 100 subjects were assigned to read a summary of the murder trial. The facts were the same in each summary, but the researchers varied the amount of detail in the description of the victim's wounds. In addition, some subjects got photographs of the victim's wounds with their summaries, some got "neutral" pictures of the crime scene, and some got no pictures at all.
The photographs had a huge influence. Only 8.8% of the mock jurors who didn't see pictures voted to convict the defendant, compared to 38.2% of those who saw neutral pictures and 41.2% of those who saw gory pictures. The level of verbal detail, on the other hand, seemed to have no effect. Why did the photographs make such a difference? Another finding suggests the answer: the jurors who saw gruesome pictures "reported higher levels of anger directed at the defendant" than the others.
Changing the facts
The 2004 study ("The Influence of Gruesome Verbal Evidence on Mock Juror Verdicts," in volume 11 of Psychiatry, Psychology and Law) focused solely on verbal evidence, but it is less striking because the researchers varied the underlying facts. In the case file they used, a husband was accused of killing his wife — but some subjects read a summary where the victim was tortured (and her mutilation was described in detail), while others read a summary where the victim was stabbed once in the chest.
Those who read the torture summary were more likely to convict, but it might not have been the gore that did it. I'm no expert, but it would seem that jurors might be more willing to believe that a random attacker was guilty of a stabbing, and that an enraged husband was more likely than a stranger to have committed the torture in the gruesome version. The paper doesn't attempt to rule out this possibility.
Protecting trials, protecting jurors
Both papers recap other research in the field. The 2006 paper also suggests another reason courts should consider excluding lurid pictures: the impact on the jurors themselves. Bright's mock jurors reported significant levels of disgust, sadness, and fear when they had to see gruesome pictures. The researchers called these intense reactions "unexpected," but real courtrooms see them often. The same week Bright's press release came out, an Australian juror vomited after hours of medical evidence including photographs of horrific injuries inflicted on a little girl.