Evidence other than testimony that is presented during the course of a civil or criminal trial. Demonstrative evidence includes actual evidence (e.g., a set of bloody gloves from a murder scene) and illustrative evidence (e.g., photographs and charts).
Many trial attorneys view the presentation of evidence to the jury as analogous to the presentation of information by a teacher to students. As in the classroom, the involvement of more than one of a juror's senses in the courtroom increases the amount of information retained by that juror. For example, combining verbal testimony from witnesses with before and after X rays, or introducing a defective machine part that jurors can hold in their hands for inspection, makes for compelling courtroom activity. In a modern, "show-me" society, the ability of a trial lawyer to use demonstrative evidence effectively can make the difference between winning and losing a case.
One common and effective example of demonstrative evidence is the still photograph. Photographs of a plaintiff's bruises taken immediately after an accident can help a jury understand those injuries in a trial that occurs months or even years after the accident, when the injuries may have healed. Aerial photographs of the scene of a vehicular accident can show how a particular intersection is laid out, and can make more clear an ambiguous description of a blind intersection given by a witness.
X rays and medical models and illustrations can be very helpful to a jury in physical injury cases. These examples of demonstrative evidence help the jury "see inside" the victim to understand the nature and extent of the injuries. X rays can show not only fractures but also permanent metal pins and plates. Accurate models of a plaintiff's head and neck can show the interaction between the cervical area of the spine and the surrounding muscle and tissues in a soft-tissue injury case. Sometimes, partial or full skeletons are brought into courtrooms to demonstrate losses or restrictions of movement due to injuries. Modern computer-generated illustrations can show the exact injury to a specific plaintiff, as opposed to the generic injury represented in a stock medical illustration.
Graphs and charts are perhaps the most useful forms of demonstrative evidence. These tools can vividly illustrate a loss of earnings, a decrease in life expectancy, and past and future medical bills. Clear and concise charts can help a jury to arrange a complex set of events in a chronological fashion. These time lines can be crucial in organizing evidence, whether in a criminal trial or in a complex SECURITIES litigation. Often, maps and other geographic charts are used to show water flow, elevation, and other physical characteristics of real property (land).
Graphs and charts can be presented to a jury in a variety of ways. In addition to offering the standard large prepared poster board on an easel, some attorneys prefer to create charts as they speak to the jury, using large blank pieces of poster board and colored marker pens. Other attorneys like the dramatic effect of dimming the courtroom lights and using an overhead projector or computer screen to focus visual attention on their illuminated charts and graphs. Whatever the style of presentation, well-constructed charts and graphs that make good use of color and are clear and easy to understand are appreciated by jurors and can have a big effect during deliberations.
Articles and objects are also forms of demonstrative evidence. In addition to actual evidence that is introduced at trial (like the knife from a murder scene), other physical articles and objects can be used to help the jury understand the testimony. For example, in a PRODUCT LIABILITY action based on a defective artificial hip, giving the jury models of ball-and-socket joints to manipulate and examine with their own hands can clarify testimony regarding the replacement joint that is still inside the plaintiff. Three-dimensional models and mock-ups of roadways, accident sites, or proposed buildings can simulate the outside world inside the courtroom to give proportion and scale to a witness's testimony.
With the permission of the judge, attorneys may be allowed to take the jurors to the scene of the crime or accident. Here, all a juror's senses are at work, and testimony presented in court can be compared to and contrasted with the physical scene. A list prepared by both attorneys of items to "notice" may be read by the bailiff at the scene. Many juries appreciate not only the chance to get outside the courtroom but also the opportunity to see for themselves the place where it all happened.
With the advent of low-cost videocassette players and recorders, it has become more and more common to see videotape in the courtroom. A "day in the life of …" video can graphically demonstrate the activities of a plaintiff living with debilitating injuries. For example, a plaintiff witness may say, "I can't pick up my children," whereas a video can actually show the plaintiff's young children milling about with the plaintiff able only to sit by and watch them. Videotapes can also show the traffic volume at a busy intersection or provide a driver's-eye view of a road sign obstructed by brush and leaves. If a jury is unable to leave the courtroom to visit the scene of a fire, a video camera can provide a tour through the burned-out remains of the family's residence. Some attorneys have actually begun hiring stuntpersons to re-create vehicular accidents, driving comparable vehicles at the speeds they were going when the accidents occurred, and filming the results. Unlike a controlled dramatic re-creation, this kind of actual re-creation, with its inherent danger yet accurate representation of accident conditions, can be an effective tool at trial.
Though waning in popularity owing to the greater availability and lower cost of computers, slide projectors and human-created animation are still used by some attorneys. By taking two slide projectors, superimposing their projections, and connecting them with a sophisticated mechanical device, an attorney can make a before picture fade into an after picture with dramatic results. As with a presentation using an overhead projector, the dark courtroom and brightly-lit screen of a slide presentation focus the jury's visual attention. Animated cartoon shorts, hand inked by artists, are eye-catching and can portray exactly what the attorney wants to emphasize to the jury: for example, a cutaway "operating" engine might show how a defective part can cause the engine to break down.
Computers and computer-generated displays are at the cutting edge of demonstrative evidence. Computer-enhanced graphics can demonstrate anything from the speed of a vehicle to the loss of range of motion on an injured portion of the body. Computers also provide high storage capacity. One CD-ROM disc can store thousands of still photos, graphs, charts, digitized video clips, and even three-dimensional computer animations. An attorney who uses a computer to coordinate a presentation can combine many different forms of demonstrative evidence into a cohesive and dramatic whole. Still photos of an injury might be followed by a digitized video showing limited physical abilities after the injury. X-ray images can fade into graphs showing a loss of earning capacity. All these exhibits can be stored in a laptop computer and presented with minimal setup and distraction to the jurors. And the attorney making the presentation can instantly return to a particular demonstrative exhibit when making a point during closing arguments.
Another significant development in courtroom technology is the use of bar codes. This technology is helpful in organizing evidence in cases with numerous exhibits. Bar codes function in court much as they do in the department or grocery store. Exhibits, be they photographs or documents, are stored on CD-ROM according
to bar code. By entering or scanning the number, the item is immediately retrieved and can be displayed on the computer screen.
Many newer courtrooms are now equipped with individual computer terminals, so that jurors may view computer displays by attorneys on individual screens in the jury box. A future development may be the use of virtual reality—where individuals see and hear computer-generated images and sounds, and through body sensors "see" their hands and body within the simulation.
No matter the technology, demonstrative evidence must still conform to standard evidentiary rules. The trial court may disallow any item of demonstrative evidence that is inaccurate or incomplete. Courts can also strike evidence if it is unnecessarily cumulative: for example, 30 photographs of one bruise that can be seen clearly in one or two photographs constitute evidence that is unnecessarily cumulative.
An attorney must keep in mind that demonstrative evidence is not real evidence: it merely illustrates the points being argued to the jury and court. Computer-generated animation may only portray evidence that has been properly presented to the jury through testimony or as physical evidence. A chart or graph may only present numbers and amounts that have been properly calculated and proved. No matter how exciting the "show," the attorney must remember that items of demonstrative evidence are merely props, and that the witnesses and their testimony are still the primary method of presenting evidence to a jury.