Reel to real: should you believe what you see?

AuthorHarts, Dean M.
PositionComputer-generated evidence

Keeping the good and eliminating the bad of computer-generated evidence will be accomplished through methods of self-authentication and vigilance

IN THE acclaimed and popular motion picture Titanic, the opening scene shows hundreds of people seeing off the ill-fated vessel on its maiden voyage. But the scene was created through digital techniques using fewer than 20 actors. In fact, one of the Academy Awards the film received was for best visual effects. Of course, Titanic is only a movie, whose audiences may not expect to see scenes true to life. What if the scene were played out in a courtroom for a jury? Who could say whether it is real or not?

This example highlights the persuasive power of digital imaging as evidence of reality. Modern jurors have grown up with television, and they believe and remember what they see. Advocates must realize digital imaging is the future, and the future is now. Today's jurors must be shown as well as told.


The legal system uses a targeted concept of evidence, defined by Black's Law Dictionary as "[a]ny species of proof[] or probative matter ... by the act of the parties and through the medium of witnesses, records, documents, exhibits, concrete objects, etc., for the purpose of inducing belief in the minds of the court or jury as to their contention." Evidence, including image-based or computer-generated evidence, is divided into two broad categories--substantive and demonstrative.

Substantive evidence is defined as that "adduced for the purpose of proving a fact in issue, as opposed to evidence given for the purpose of discrediting a witness (i.e., showing that he is unworthy of belief), or of corroborating his testimony." Demonstrative evidence is defined as that "addressed directly to the senses without intervention of testimony.... Such evidence is concerned with real objects which illustrate some verbal testimony ... [and] may include maps, diagrams, photographs, models, charts, medical illustrations, X-rays."

The purpose for which one intends to use computer-generated evidence such as charts, diagrams, simulations and reenactments may determine its admissibility.(1)

  1. Substantive Evidence

    The initial admissibility determination for computer-generated evidence remains with the trial judge using a preponderance of the evidence standard.(2) When witnesses are not testifying as experts, their testimony is admitted regarding observation and first-hand knowledge(3) but limited when based on opinion or inference.(4) The purpose of the Federal Rules of Evidence, as well as state rules, includes assuring that all scientific, technical, or specialized knowledge evidence and testimony admitted is relevant and reliable.(5)

    "High technology" evidence embodying independent probative value may be used as substantive evidence.(6) The rule for general acceptance of scientific evidence dates from the 1923 decision in Frye v. United States,(7) in which the D.C. Circuit required "general acceptance" within the scientific community from which the novel scientific evidence arose before it could be used as evidence. The Frye standard ruled for about 70 years, keeping several advances in scientific knowledge from being used as evidence until they were no longer novel. Some of the advances raising evidentiary issues include photography,(8) x-rays,(9) the polygraph,(10) hypnosis,(11) and more recently videotape,(12) computer simulations and animations,(13) and DNA.(14)

    Holding that the Federal Rules of Evidence superseded the Frye standard, the U.S. Supreme Court in 1993 in Daubert v. Merrell Dow Pharmaceuticals Inc. rejected the "general acceptance" standard as the sole test for admissibility of scientific evidence.(15) That case involved limb reduction birth defects allegedly linked to the mother's ingestion of Bendictin. The district court had granted summary judgment to the drug's manufacturer, holding that the plaintiff's expert evidence did not meet the general acceptance standard, and the Ninth Circuit agreed that the expert opinion was inadmissible because it was based on reanalysis of statistical data in earlier published studies, a technique not generally accepted.

    Writing for the Court, Justice Blackmun listed several flexible factors for admissibility consideration, including whether the evidence had been subjected to peer review, whether the expert's theories and methods could be tested, the error rates in studies and test results, and the degree of acceptance of the expert's theories and methods.

    Using computer-generated evidence frequently invokes the use of expert opinion.(16) Once a foundation has been provided to qualify a witness as an expert, the expert is free to use opinions and inferences to assist the trier of fact to understand the computer-generated evidence. Under Federal Rule 703, the expert also may base an opinion or inference on facts or data that are not admissible as evidence, and, under Rule 705, the expert need not disclose the underlying basis for the opinion or inference. However, the expert is still subject to cross-examination, during which the underlying facts must be disclosed. And Rule 706(a) permits the court to appoint its own experts or under Rule 201(b) to take judicial notice of any scientific basis when the theory has attained the status of accepted scientific validity.

    There is no requirement that involving a computer in the generation or presentation of evidence includes any science pertaining to the evidence.(17) One may generate an image entirely from the imagination, as well as generating an image of reality.(18) Since one creates computer-generated evidence first with input data and then through the use of computer software manipulates this data, the data, the software and any extrinsic statements of the computer programmer are subject to hearsay objections.(19) Of course, several exceptions are available to overcome the hearsay rule, including admissions by a party (Rule 801(d)(2)), the business records exception (Rule 803(6)), the public records exception (Rule 803(8)), and the "catch-all" exception (Rule 807). Each of these exceptions hinges on the nature of the computer-generated evidence.

  2. Demonstrative Evidence

    When evidence carries no independent probative value, it may be used as demonstrative evidence to aid counsel in opening or closing arguments or to aid the testimony of a witness. Generally, there are five purposes of demonstrative evidence: to educate your audience; to explain something; to persuade your audience of something; to dissuade your audience of something; to reinforce something your audience already believes.(20)

    The use of demonstrative evidence has a long history in the courtroom, from chalkboards, maps and diagrams to photographs, films and video.(21) Common spreadsheet and graphics programs allow one to create high-quality charts, diagrams and illustrations with a computer. While maps and diagrams have always played major roles in trials, the computer revolution has made a major impact by enabling these items to be generated quicker and much less expensively than ever before. Professional services use more complex modeling software to create more sophisticated graphics.(22)

    Litigators believe the maxim that "a picture is worth a thousand words." The expanding importance of demonstrative evidence has paralleled the increasing pervasiveness of visual media in today's world. Photographs have become "one of the most effective forms of evidence." Because people and courts believe photographs are truthful and accurate, their evidentiary value generally has been substantial.(23)

    The threshold test of admissibility of demonstrative evidence is relevance. Moreover, the probative value of the demonstration must not be substantially outweighed by the danger of unfair prejudice, misleading the jury, or wasting time. Finally, a proper foundation must be provided to prove the authenticity of the evidence.

    With computer technology impacting nearly every area of human activity, it probably was inevitable that it also would revolutionize photography and impact the law of evidence. There is, however, a key difference between photographic evidence and the typical videotape. A photographic process normally leaves a trail, the negative, while video is usually stored in a form of re-recordable computer media.(24) Computer-generated visual evidence may fall within the bounds of substantive evidence, demonstrative evidence, or include components of both.


  3. Definition

    A digital image is one stored in binary code via magnetic or optical media that can be displayed by using a videotape player or computer. This is quite unlike historical photographic images.(25)

  4. Types

    1. Still

      An image may be scanned into a computer from a photograph or even a hand sketch.(26) One may also download images from a digital camera or the Internet. Widely used computer image file storage formats usually are identified by the filename extension, such as bitmap (.bmp), JPEG (.jpg), .gif, .tif, .pic, and ZIP.(27) Most of these formats are independent of the computer's operating system. Thus, a .jpg image, for example, can be read or recorded by an IBM PC-type computer, typically running the Microsoft Windows operating system, or a Macintosh running the Apple system software.

      Several of these formats actually store a compressed version of the image, usually to save storage space, because image files normally consume vast quantities of memory and storage space. Examples include architectural or machine drawings, consisting mainly of lines and text, to stock photographs, and from simple objects to the extremely intricate.(28)

    2. Animation

      A basic computer animation can be prepared by drawing a series of related images and progressing from an...

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