George Zimmerman, Trayvon Martin & The Admissibility of Computer Generated Animations as Demonstrative Evidence

One of the big issues in the now-concluding George Zimmerman-Trayvon Martin trial was whether the defense would be able to admit an animation depicting the fatal fight between Zimmerman and Martin. Unsurprisingly, the court concluded that the animation would be inadmissible as substantive evidence to prove that the animation in fact accurately depicted how the fight occurred. The court, however, did deem the animation admissible as demonstrative evidence. As I have noted before,

In contrast to testimonial or documentary evidence, demonstrative evidence is "principally used to illustrate or explain other testimonial, documentary or real proof, or judicially noticed fact. It is, in short, a visual (or other) sensory aid." A diagram of the scene of a crime drawn on a board by a percipient witness who is present at trial to testify would be classic demonstrative evidence. Whereas the diagram illustrates the witness' testimony, it should, technically speaking, add nothing further. In this way and despite its title as "evidence," demonstrative evidence is more of a visual aid than evidence per se because it merely illustrates or "demonstrate[s]" a witness' testimony. Jessica M. Silbey, Judges as Film Critics: New Approaches to Filmic Evidence, 37 U. Mich. J.L. Reform 493, 503 (2004).

Perhaps the most (in)famous example of demonstrative evidence was the failed glove experiment in the O.J. Simpson trial.

Beginning in the 1990s, courts began to set forth tests governing the admissibility of computer animations and other computer generated evidence (CGE), and that's exactly when the District Court of Appeal of Florida, Fourth District, decided Pierce v. State, 671 So.2d 186 (Fla.App. 4 Dist. 1996).

In Pierce, the appellate court quickly decided that the trial court erred in its instruction regarding reasonable doubt, requiring reversal. Thereafter, the court noted that

because we are faced with an issue of first impression for any court in this state, we write to address the dynamic aspect of computer animations as substantive and demonstrative evidence.

Pierce was charged with vehicular homicide, and the prosecution had admitted a computer generated animation of the accident as demonstrative evidence at his trial. In reviewing the issue of the admissibility of such evidence, the court noted that

Computer animations have been used in the courtroom by civil litigators for reconstructing accidents, including automobile and truck accidents, aircraft collisions, construction equipment accidents, and industrial accidents, as well as in patent litigation....As demonstrative aids to illustrate and explain testimony of witnesses to the fact finder, such exhibits have been useful. Computer animations have also been offered as substantive evidence to supply missing information for the purpose of proving a material fact in dispute. In this context, unlike the case at bar, the expert uses the computer not to illustrate the expert's opinion, but to perform calculations and obtain results which form the basis of the expert opinion....Several cases have been decided in other jurisdictions that deal with the admissibility of computer animations as substantive scientific evidence. The Frye requirement that scientific evidence be admitted only if derived from principles and procedures that have achieved general acceptance in the scientific field to which they belong has been applied to such computer animations introduced as substantive evidence.

So, if a party seeks to admit an animation as substantive evidence, the typical rules regarding the admission of expert evidence -- the Frye test in Florida and some other states and the federal Daubert test that also applies in many states --govern the admissibility decision. Conversely,

Because the computer animation in [Pierce] was admitted solely as an illustration of [a detective]'s opinion of how the accident occurred, we do not now decide the standards applicable to computer animations introduced as substantive evidence. The trial court, following a lengthy pretrial hearing, determined that the demonstrative exhibit was not subject to the Frye analysis. We agree....

Therefore, when computer animations are simply offered as demonstartive evidence, they are not governed by the typical expert evidence rules. That said, the analysis is pretty much the same. Here is what the court said on the issue in Pierce:

In order to admit a demonstrative exhibit, illustrating an expert''s opinion, such as a computer generated animation, the proponent must establish the foundation requirements necessary to introduce the expert opinion. Specifically, (1) the opinion evidence must be helpful to the trier of fact; (2) the witness must be qualified as an expert; (3) the opinion evidence must be applied to evidence offered at trial; and (4) pursuant to section 90.403, Florida Statutes (1991), the evidence, although technically relevant, must not present a substantial danger of unfair prejudice that outweighs its probative value....

In addition, the proponent must establish that the facts or data on which the expert relied in forming the opinion expressed by the computer animation are of a type reasonably relied upon by experts in the subject area. The facts or data need not themselves be admissible in evidence....The reasonableness of the expert's reliance upon the facts and data may be questioned in cross-examination.... 

Finally, the computer animation must be a fair and accurate depiction of that which it purports to be. This is, of course, the same foundation which must be established to admit any pictorial representation, be it videotape, motion picture or photograph....

All preliminary facts, constituting the foundation for admissibility of evidence, must be proven to the court only by a preponderance of the evidence, even in a criminal case....In the case at bar, the trial court made appropriate findings of preliminary facts which were supported by the evidence adduced at the pretrial hearing. [The detective] was found to be qualified as an expert. His opinion as to how the accident occurred was in fact applied to evidence offered at trial, and the trial court found that the data relied on by the expert to form his opinion was of a type reasonably relied upon by experts in the field. Further, the trial court specifically found the computer animation tape was a fair and accurate depiction of the expert's opinion as to how the accident occurred, and found that the opinion, as well as the computer animation, would be helpful to the jury in understanding the issues in the case. Our review of the record has revealed no abuse of the trial court's discretion in these preliminary findings.

Furthermore, our review of the computer animation videotape in the context of this record convinces us that the trial court appropriately exercised its discretion in its balancing analysis...Although evidence in this case indicated a bloody scene with screaming victims, the computer animation videotape demonstrated no blood and replicated no sound. Further, the mannequins used in the computer animation videotape depicted no facial expressions. Although some testimony indicated that the truck was traveling up to twice the posted speed limit, the videotape depicted the truck travelling at the posted speed limit.  Moreover, we find there was no undue emphasis placed upon the computer animation videotape, which was shown to the jury for a total of approximately six minutes in the course of an eleven day trial. The judge appropriately explained to the jury that the videotape was being used only to illustrate the expert's opinion. Cross-examination was permitted and the record demonstrates it was made clear to the jury that if the information entered into the computer was inaccurate, then the computer animation itself was inaccurate.

So, when the judge in the George Zimmerman/Trayvon Martin case deemed the computer generated animation admissible as demonstrative evidence, this was basically the analysis that she applied.

-CM