The Court of Appeals has given the green light to the prosecution’s use of PowerPoint on summation, reasoning that visual demonstrations can be evaluated in the same way as oral statements (NYLJ, April 6). But the dissent points out that there’s a big difference between how we process images and words. Because we tend to uncritically believe what we see, the persuasiveness of visual demonstrations has the potential to interfere with the kind of reasoned deliberation we expect of a jury.
This controversy isn’t new. Wigmore observed over a century ago that visual demonstrations can positively substitute for proof. Does Doe accuse Roe of stealing a horse? Have a horse brought into the courtroom and triumphantly say, “If you doubt me, there is the very horse!” The jury will consider the sight of the horse to be definitive corroboration and ignore any weakness of the evidence against Roe. See 7 Wigmore on Evidence §2129.
