Computer-generated evidence: testing the envelope.

• Author: Hannan, Edward A.
• Position: Coping with Science

RECENT reductions in cost and exponential increases in capacity and processing speeds have rendered computer technology not only accessible to courts and increasingly essential to litigation management, but also ever more influential over the fact-finding process. Text, numbers, equations, photographs, videos, sounds--all can be reduced to binary expressions, stored electronically and fully manipulated.

The potential applications and uses of computer technology in the courtroom are limited only by counsel's imagination. The evidentiary issues underlying the admissibility of still photographs pale in comparison to the conundrums spawned by dynamic, computer-generated images, which are as "persuasive" as they are capable of subtle distortion. Computer-generated evidence highlights some fundamental weaknesses in the implicit assumptions underlying the evidentiary rules. This article attempts, ataxically, to identify and comment on a few.

THE HUMAN EQUATION

Although human beings are capable of speaking at rates of 150 to 200 words per minute, it is believed they are capable of receiving, processing and "comprehending" data at a much higher rate. Studies have suggested that a mode presenting information that engages both the senses of sight and sound yields retention six times greater than mere verbal presentation alone.(1) Yet, the method by which human neural synapses process two-dimensional retinal phenomena into three-dimensional images, or waves of certain frequency and amplitude into the sense of sound is, simply put, not understood.

"Seeing" may not necessarily justify "believing." Perfectly familiar examples of mirage--of "misperceiving" matters as they "are"--abound. The stick immersed in water appears to be "bent," although "in reality" it is "straight." Trees on a distant mountainside "appear" to be greyish-blue, although on approach they "are" dark green. Two lines in the Muller illusion--one with arrows pointing inward and the other with arrows pointing outward--appear to be of different "length," although they are equally long. When illuminated by primarily yellow light, a "blue" dress appears to be "black." As the train or ambulance approaches, the whistle or siren seems to be of higher "pitch" than when it recedes, although the frequency and amplitude is "constant." Water in the same vessel will seem "warm" to a hand that has been immersed in cold water and "cold" to another hand that has been immersed in warmer water, although the "actual temperature" is uniform throughout the vessel. Indeed, perceiving phenomena that do not "exist" is well known: press your eyeball and you will "see" two candles or light bulbs when only "one" is "there."

Without the aid of instrumentation or machinery, the five senses are quite capable of deception by sublime "illusions" from relatively "static" and seemingly "familiar" objects and circumstances. These initial sensory deficits are compounded immeasurably by the mysterious ways in which the brain processes "data" received by the senses. Such compounding is magnified inestimably through emotion, bias, prejudice and habit.(2) What, then, are the "circumstantial guarantees of trustworthiness"(3) that ought to govern the admissibility of computer-generated evidence and how ought these circumstances be assessed and applied to this versatile tool?

THE COMPUTER EQUATION

Computer-generated evidence, CGE for short, is indeed extraordinarily versatile. For example, it has been proffered to re-create airplane accidents,(4) to re-enact automobile accidents,(5) to assess the fair market value of land based on projected present values of royalty interests in gas and oil wells,(6) to demonstrate the perfectibility of products,(7) and to construct hypothetical markets in an antitrust claim for purposes of illustrating anticompetitive behavior.(8)

The suitability of applying to CGE the evidentiary rules antedating the arrival of computerized technology by some distance has been and continues to be the subject of substantial debate in contemporary literature.(9) The academic debates reflect substantial suspicions that the versatility of CGE is offset by its subtlety and by its potential for confusion and for misleading errors.

But it's here to stay, and defense counsel must anticipate that its prevalence in the courtroom will continue to grow.(10) It would be wise to invest some time to become familiar with the various types of CGE, their potential functions, and the evidentiary concepts currently governing the admissibility of CGE.

TYPES AND USES OF CGE

CGE can be classified generally into four categories: (1) static images or still illustrations, (2) general animations, (3) simulations or recreations and (4) computerized models.(11) The evidentiary hurdles that CGE must surmount may depend in part on how a court classifies the evidence.(12)

1. Static Images

   Static images or static illustrations are merely two or three dimensional, non-moving pictures drawn by a computer rather than by hand. An example is an accident reconstruction diagram or a CAD drawing for building components. The images may be printed on paper or displayed on a monitor or screen. This style of evidence is akin to traditional pictorial evidence.

2. Animations

   Animations consist of a series of computer-generated images that are subject to manipulation. The persuasive force of an animation springs from engaging the sense of sight dynamically, engaging multiple senses simultaneously (sight and sound), or both. Animations enable zooming in and out of scenes, enlarging or reducing objects, telescoping or collapsing of time, and the rotating of objects. Animations can be placed in three sub-categories, according to their function--general animations, simulations or re-creations, and models.

   1. General Animations (Dynamic Illustrations)

      A general animation, or dynamic illustration, introduces movement into otherwise still images for purposes of general illustration. Two- or three-dimensional objects may be rotated to permit viewings from differing angles or perspectives, a sort of "fly-by" of a building, or people may move from point to point for illustrative purposes. General animations, however, are not intended to simulate or re-create an event.(13)

   2. Re-creations or Simulations

      A computer-generated re-creation, or simulation, employs animated two- or three-dimensional images purporting to show what actually happened at a given time and place.(14) The data used to create the images are based on empirical measurement of the size, shape, mass and other physical or mechanical properties of an object and are processed by formulae that simultaneously and accurately plot movement in three independent coordinate planes, according to principles of Newtonian mechanics and other physical laws.(15)

   3. Computer Models

      One writer notes that a computer model differs from a computerized simulation in that the former is used by an expert to arrive at [an] opinion, while the latter is used to illustrate [the] opinion so that it can be visualized by a jury. This writer describes a computer model as follows:

      Computer models are nothing more than a compilation

      of mathematical formulae and expressions

      that are integrated into a sophisticated computer

      program or series of programs. The formulae

      are based on scientific principles, such as porosity,

      permeability, absorption and flow. An expert

      is able to input into the computer several

      variables along with well known information in

      order to test different hypotheses. Based on the

      results of the computer model, the expert is able

      to form an opinion on the subject that he is studying.(16)

      Computerized models are the most sophisticated form of CGE and, not surprisingly, the form subject to the heaviest evidentiary burdens for admissibility.

      WHEN WILL CGE BE HELPFUL?

      CGE is not required in every case, nor is CGE necessarily the best medium. Photos and sketches can go to the jury room, while evidence requiring access via computer is not likely to be routinely sent to the jury room. CGE also is expensive to produce, requires significant supervision for authentication of underlying data, and is likely to be viewed with greater judicial suspicion than would be routine photos or even videotapes.

      While CGE may not be appropriate in every instance, it can be of assistance in explaining conditions and events not within the daily experiences of the average juror. For example, a computerized simulation is capable of simultaneously placing each juror in the driver's seat of a car moving through a blind intersection or in the co-pilot's seat of an aircraft as it hurtles into oblivion. Or, through a simulation, a jury may be afforded a collective view of the origin of a warehouse fire and experience the progress of the conflagration in real time as the flame front spreads upward and outward over materials stored on racks. CGE can assist in enabling a person to visualize difficult abstractions, such as cash flows among related corporate entities, the vagaries of equity financing as opposed to debt financing, or submarkets within general markets.

      CGE should be considered when:

      * the visualization of an event, object or condition is complicated by dynamic factors that may be difficult to explain verbally;

      * the "real time" of the event is important, such as the timing of an automobile accident;

      * physical re-creation of...