The research I’m about to present resonates with a personal experience of mine. Three years ago, I served on a jury that acquitted Cheswick, PA, councilman Jonathan Skedel on a charge of assaulting Joe Ferrero, president of the Cheswick Volunteer Fire Department. (I was stunned when the prosecutor allowed a retired college professor whose field is social psychology to sit on the jury.) The charge resulted from a fistfight between the two men in which Ferrero suffered facial injuries requiring dental surgery. The fight took place in the parking lot of a physical therapy clinic and the entire episode was captured by one of our ubiquitous surveillance cameras.
The video was played several times during the trial, both at real speed and in slow motion. In his summation, the prosecutor paused the video just before Mr. Skedel delivered the punch which injured Mr. Ferrero, and stated that Mr. Skedel could have stopped the fight at that point, but instead decided to assault Mr. Ferrero.
During the jury’s deliberations, I was disturbed to discover that some of my fellow jurors accepted the prosecutor’s definition of the situation. I tried my best to argue—with limited success—that pausing the video was an artificial intervention in what was, in reality, a continuous episode that provided little opportunity for conscious deliberation by either man. The jury eventually acquitted Mr. Skedel, but this was probably due to the majority’s belief that both men had acted equally badly, and it was unfair to single out one of them for prosecution.
Playing crime scene videos in slow motion, or pausing them at critical points, is common practice in jury trials and their effects should be investigated. The former of these issues was the subject of four experiments by Dr. Eugene Caruso of the University of Chicago and his colleagues. They compared the effects of watching a video either in slow motion or at regular speed. Their slow motion was 2.25 times slower than regular speed. The researchers measured participants’ estimates of how much time had passed, and their judgments of the intentionality of the defendant’s behavior.
Three of these experiments used a surveillance video from a Philadelphia trial in which the defendant, John Lewis, was convicted of first degree murder for shooting a man during a convenience store robbery. Here it is (in slow motion).
They measured the intentionality of the act because the real jury had to decide whether the defendant was guilty of first degree murder, which is premeditated, or second degree murder, which is not.
Study 1 showed that participants in the slow motion condition estimated that more time had passed than those in the real time condition, and saw the defendant’s behavior as more intentional. Further analysis showed that their judgments of intention were mediated by their estimates of how much time had passed. The researchers refer to this effect of slow motion on perceived intentionality as the intentionality bias. It occurs because the participants mistakenly infer that the defendant had more time to think before acting than he actually had. Study 2 replicated this finding with a video of a professional football tackle involving violent contact. (You might want to remember this the next time you watch a slow motion replay during a sports event.)
Mr. Lewis’s lawyers argued on appeal that showing the slow motion video had biased the jurors, causing them to see his actions as more intentional than they actually were. The judges rejected this argument because, they said, the jurors were shown the video at regular speed as well as slow motion, and because the amount of elapsed time was stamped on the video.
The researchers effectively demolished both of these arguments. Study 3 added a “time salient” condition in which participants were reminded that they could see how much time had elapsed from the time stamp on the videotape (which was present in all conditions). This reduced the amount of intentionality bias produced by slow motion, but did not eliminate it. Finally, Study 4 included a condition in which participants were shown the video twice, first at regular speed and again in slow motion. This too reduced the magnitude of the intentionality bias but did not eliminate it.
Summarizing the data, the researchers calculated that, prior to deliberation, juries randomly composed of Study 1 participants would be almost four times as likely to unanimously believe that the killing was premeditated in the slow motion condition.
Unfortunately, Dr. Caruso and his colleagues did not include a condition in which the video was paused immediately before the critical action took place. My guess is that such a condition would have further increased the intentionality bias, since it stretches the length of the presentation.
The use of slow motion is often justified on the grounds that it provides a “better” look at an event, and this may be true in some instances. However, when intentionality is at issue, slow motion also produces a biased causal attribution for the event. These studies are probably too late to help Mr. Lewis, who was sentenced to death and is awaiting execution.
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