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Demonstrative Evidence – Powerful Persuader

05 Aug Demonstrative Evidence – Powerful Persuader

Commentators generally agree on one fundamental point: “Visual, tangible evidence has powerful impact.”[52]

No doubt – but there are two sides to the fact that people remember the pictures.

Chayko and Gulliver in Forensic Evidence in Canada[53] suggested that “both real and demonstrative evidence are important because they are impressive. Although one can still argue about their usefulness in deciding some fact, they are closer to the real event than a witness’ verbal testimony…most types of demonstrative evidence allow more accurate and clearer descriptions of the person, place or thing than verbal testimony by a number of witnesses.”[54]

John Olah described “demonstrative evidence” as “perhaps the most powerful tool of persuasion available to the trial lawyer… a silent witness that speaks for itself. Demonstrative evidence can be used in any phase of the trial… the only limiting factor is your imagination.”[55] Olah quoted American trial lawyer Melvin Belli in describing demonstrative evidence as “the highest proof man can achieve in the absence of a scientific standard.”[56]

An American commentator advocated the use of “trial graphics” because they “grab… audience attention, simplify complex issues and relationships and aid retention of key points.”[57]

“Human factors research has shown that the majority of people are actually visual, as opposed to auditory, learners. They process visual information more efficiently.”[58]

Legate wrote that retention of information presented both visually and orally is greatly enhanced over information presented only orally. “We must cast off our own perceptions of how we learn (reading and listening) and seek to understand how our audience, jurors, learn (seeing, listening, touching, reading, experiencing) in a very visual and interactive world… nor can we assume that there is something mystical and untrustworthy or inherently suspect about visual learning. Indeed, the evidence is otherwise. Retention of information presented both visually and orally is greatly enhanced over information presented only orally. Understanding is enhanced – a picture is worth a thousand words…The litigator who ignores the power of demonstrative evidence does so at his or her client’s peril.” [59]

According to advocacy speaker Todd Winegar, more than 80 percent of the information we learn comes through our eyes. “Your jury (and judge, and mediator) is accustomed to learning information through their eyes, not their ears. Most attorneys are tied to the radio generation. Years of law school lectures have dulled our senses. To communicate effectively, you must graduate to the television generation and present a wide array of visual information which compliments your oral presentation and explains your case.”[60]

David Hennes quoted a panel discussion on communicating with juries for the proposition that individuals and jurors enhance their capability to perceive and learn through the use of sight. Information received via sight has a profound impact upon individuals…far more learning occurs via sight than through any of the other senses:

“This reality has led to the conclusion that if a lawyer keeps in mind that the great majority that jurors learn will be through their eyes, he can be sure the jury will learn and remember the facts as he wishes them remembered and render their verdict accordingly. Practitioners are well aware of the benefits of using visual presentations and are frequently advised to ‘show the jury’ in addition to telling them. Oral testimony is not the primary source of information retained by jurors; visual presentations account for the vast majority of retained information.”[61]

Thus, Legate wrote “more than one lawyer has expressed the view that the failure to use demonstrative evidence in any complicated case approaches negligence.” [62]

Olah described demonstrative advocacy as “so persuasive” because it permits the recipient to visualize what is given in oral testimony. It is said to accomplish this by transforming complicated evidence into a simple, visual presentation. Thus, it “graphically portrays and underscores” oral testimony.

“It is highly compelling because it is vivid: it brings oral evidence alive. More importantly, the amount of information retained by the trier-of-fact is substantially increased when the information is conveyed by demonstrative evidence in conjunction with oral testimony. Not only does it help the trier to understand the evidence, but it increases the probability that the testimony will be remembered. When demonstrative evidence is advanced by an expert witness, it adds to his credibility, and it reinforces his testimony.” [63]

It has also been suggested that those who support extensive use of demonstrative evidence subscribe to the view that it is easier to show jurors what is being described, rather than waste time and risk the confusion of jurors by relying solely on oral testimony.”[64]

However, the enthusiasm of commentators for visual evidence seems not to be limited to its impact on learning. Rather, the emphasis is on the advocate’s ability to make certain evidence vivid. In other words, the power of demonstrative evidence is not just because it aids understanding – it is because of its impact. It is the evidence that will be remembered.

Sheila Block wrote that “life is full of experiences that cannot truly be described.”[65] However, experiences are not simply being described. They are being dramatized.

Indeed, demonstrative evidence is not recommended or used simply because it assists witnesses to describe experiences or events or because it assists the trier-of-fact in understanding or remembering complicated evidence. Demonstrative evidence, particularly computer-generated animations, have come to be regarded as a form of reality by which the trier-of-fact is virtually transported back to the scene of an experience or event such as to become an “eyewitness” and then draw her or his own inferences.

In 1992, an American commentator predicted that “criminal trials are on the verge of a technological revolution that will allow lawyers to transform experts’ dry, verbal testimony into dynamic, TV-like shows that can mentally transport jurors to crime scenes and play out for them an advocate’s version of events.”[66]

In an article on the animation of accident reconstruction reports, an interviewee enthused that:

“(With animation) you can almost transport the jury back there”[67]…‘This animation was incredible’ a pathologist was quoted as saying. ‘The courtroom was so silent you could hear a pin drop, it was just overwhelming.’[68]… when somebody looks at something, it integrates in their subconscious… they get a sense that they witnessed it and they’ve seen someone’s version of it…”.[69]

However, this note of caution in the same article:

“That’s the power and danger of forensic animation. It’s a double sided coin. It really has a tremendous psychological power and that’s why judges have been so afraid of it.”[70]

Hennes suggested that: “Thus, it can be concluded that when an individual or a juror views videotaped material, that material is in fact vivid, resulting in enhanced availability in the inferential process and potential overvaluation in decision-making.”[71]

A company called MedLegalVisuals boasts that it specializes in creating demonstrative evidence with “dramatic impact for all types of personal injury and medical malpractice cases.” The company’s ad boasts:

“Maximize your case presentation with medical exhibits that are visually dramatic, accurate, easy to understand and cost effective.”[72]

“Trial Exhibits graphically depict the nature and extent of the specific injuries suffered by your client. Created directly from your client’s diagnostic films, operative reports and medical records, these visual aids can maximize the effectiveness of your settlement negotiations and increase the value of your case.”[73]

This type of promotion is not mere puffery. According to a 1982 study by Whalen and Blanchard, colour pictures presented during a trial of a child’s injuries were more dramatic and had more impact on monetary awards than other evidence.[74]

Hennes cited articles in which defense lawyers discussed potential objections, strategies and motions to counteract a plaintiff’s use of “day in the life” videos because “they will rivet the jury’s attention like no other evidence and bring home to the most hardened heart the plight of a severely injured plaintiff”, and “can present a more persuasive picture of the nature and extent of a severe injury than other types of evidence.”[75]

However, should there be different monetary awards for the same injury? In some cases the visual presentation may help the trier-of-fact understand the injury so as to properly assess damages. In other cases, its purpose may be to diminish more probative, albeit oral, evidence as to an excellent recovery from the same injury.

The greatest benefit/danger of demonstrative evidence is its ability to dramatize, much more so than to illustrate or explain. It is the “vivid” in visual that has the greatest impact. It is also the vivid that has the greatest potential to induce bias, distort fact-finding and cause cognitive error.

Indeed, one well-known lawyer and author has written that there should be limiting factors apart from John Olah’s suggestion that the only limit is “your imagination”.

Geoffrey Adair wrote in “On Trial” that:

“Counsel are now making every effort to dramatically expand the repertoire of acceptable demonstrative evidence aids. Complex and expensive computer reconstructions of motor vehicle accidents or other occurrences, videos demonstrating the sheering nature of a brain injury and video tapes of out-of-court experiences by experts are illustrative of the new wave of purported demonstrative aids. All of this material is presented under the guise that it will assist the trier-of-fact in determining the real merits of the case.

“These expanded efforts, however, raise serious issues centering upon fairness in the trial process and the extent to which the adversary system will become a ‘virtual’ contest to the detriment of the fact-finding exercise. Is it fair to allow a jury to swayed by a high-tech computer reconstruction of a motor vehicle accident prepared on the basis of facts that are much in contest? Does the introduction video purporting to show how a brain injury may be caused by sheer forces really help illustrate the plaintiff’s medical evidence, or does the video carry the impact of evidence (which cannot be cross-examined upon) tending to bolster the plaintiff’s claim that he sustained a head injury even in the absence of a direct blow? When does the use of charts summarizing certain pieces of evidence in colour cross the line from assisting the court’s recollection of same to providing one party or the other with an additional chance during deliberations to play up only part of the case to the trier-of-fact?

“…the lack of criteria for the use of demonstrative aids at trial is most unfortunate. It is beyond argument that visual materials (especially those in colour that simulate or record movement) may have a substantial impact upon the viewer. They may represent a reasonable and valuable tool for educating the trier-of-fact, and yet by their varying nature they cannot be cross-examined upon. If a picture is truly worth one thousand words, then an aid which lacks true simulation with ultimately accepted fact may leave a strong but false impression as to how an occurrence took place. Visual aids are subject to all sorts of inaccuracy and distortion, intended or otherwise.”[76]

Adair suggested that the sole legitimate use of demonstrative aids is to illustrate the evidence of a witness. Accordingly, such aids should not be permitted either where their true purpose is other than illustration of the evidence of the witness or where such illustration is not reasonably necessary or would risk introducing a note of unfairness in the trial process.

“The court must be particularly vigilant to guard against the introduction of demonstrative aids whose real purpose is to persuade the trier-of-fact to the righteousness of a contentious theory that is in issue in the case.. (and) a trial becoming a contest as to which side has the most impressive simulations of the injury or accident regardless as to whether either simulation accords with the facts the court may ultimately accept as correct.”[77]

The difficulty, of course, is discerning when the “true purpose” of demonstrative evidence is merely to illustrate the evidence of a witness. As noted, the advocate’s true purpose is persuasion far more than illustration. As well, and as noted, the impact of the evidence may be subtle and, hence, undetectable.

As Adair noted, the issue is not simply one of reliability but also of distortion.

Some may argue that whereas demonstrative evidence cannot be cross-examined upon those who testify as to its reliability may be cross-examined.

However, cross-examination is no safeguard if no one is listening.

As Vincent Bugliosi wrote concerning the O.J. Simpson case: “The much greater part of mankind only hears the music, not the lyrics, of human events…”[78].

People remember the pictures.

Hennes suggested that when evidence promotes the imaginability or sensory imagery of the event in dispute, it is more likely to be vivid. “Vivid information attracts attention, makes the information seem more concrete and personable, and most importantly, makes information more memorable.”[79]

Hennes argued:

“Informing the jury that the victim died of fatal injuries suffered in a car accident is less likely to provoke a vivid response in a jury’s mind than is informing them that the victim was killed when run over by an 18-wheel truck that flattened the car and crushed the driver’s skull… in the latter description, the jury’s instincts of concern and outrage could lead to a desire to punish the wrongdoer or to impose compensatory damages for such grievous bodily injury. As a result of the former description, a juror’s response may more likely be ‘well, accidents happen.’

“Similarly, the description ‘plaintiff was severely injured’ is not likely to have nearly the impact of ‘blood was gushing from the knife wounds in the plaintiff’s back.’ Thus, although both forms of the testimony relate to the same event, the latter description is more vivid, and thereby will have more of an impact on the decision-making process. Yet vividness bears no relation to actual liability or culpability and is likely to cause inferential error if used as the primary source of information or decision-making.”[80]

Thus, vivid information, which is concrete and image-provoking, affects inferential processes through memory because it is more readily retained and more quickly recalled. “By impacting memory in this manner, vivid information is likely to be more available for decision-making and more likely to be accepted as representative of the objects or events it describes than is pallid evidence.”[81]

Hennes argued that the dangers posed by vivid evidence occur when that evidence’s vividness exceeds its objective probative value. This will cause “cognitive overreliance” upon that piece of evidence and unfair prejudice to occur, because the jury will rely disproportionately on the vivid piece of evidence. Hennes called this “inferential error”.

Concern as to the persuasive power of a “day in the life” film motivated an American court in 1979 to exclude the evidence. In her article on film evidence in court[82], Jessica Silbey referred to the 1979 trial involving a man who was burned very badly in an automobile accident. A month after his accident, while enduring the painful and intense physical therapy required to rehabilitate burn victims, the plaintiff’s attorneys arranged to film one of the physical therapy sessions. The defendant filed a motion to exclude the film from evidence at trial. The court acknowledged that words generally are inadequate to fully capture the plaintiff’s pain and suffering. Nevertheless, according to Silbey, the court felt that the film would unduly dominate the evidence at trial.

“During the course of the trial, the presentation of the tape may consume an appreciably greater proportion of the anticipated trial time. The novelty of using a video tape in the courtroom in and of itself may make the tape stand out in the minds of the jury. Unquestionably, it will dominate the evidentiary scene.”[83]

Crime Reenactments and Inferential or Cognitive Error

The need for judges to be “circumspect” in relation to evidence that may be given more weight than it deserves has been confirmed in relation to expert evidence. The concern is that evidence may be given more weight than it deserves simply because it emanates from an “expert”.[84]

As noted, evidence that is vivid may also be given more weight than it deserves. Thus, it follows that judges must also be circumspect in relation to all vivid evidence.

Some suggest that “people today because of their exposure to television and motion pictures can be expected to be much less sensitive to graphic displays of injuries than average nineteenth or early twentieth century citizens. This is particularly true of graphic and sometimes shocking photographs or videotapes.”[85]

However, and with respect, this proposition appears not to be supported by a significant, or any, body of accepted psychological or other study. It is, in fact, contrary to the conclusion expressed in at least one study and may be nothing more than a manifestation of egocentric bias which the study’s authors found even judges to exhibit.[86]

As well, to focus solely on whether or not a graphic or vivid piece of evidence is likely to inflame the trier-of-fact is to ignore the equally important concern that graphic, vivid evidence will be given greater weight than it deserves and therefore distort the fact-finding process.

Kirker and Mason recognized that the issue of probative value versus prejudice was not limited to appeals to emotion:

“Ultimately, trial judges have the discretion to exclude relevant evidence if the probative value of the evidence is overcome by its prejudicial effect, the evidence is potentially misleading, or its admission consumes an inordinate amount of court time which is disproportionate to its evidential value. In other words, there exists a discretion to disallow otherwise admissible evidence where it would have an unfair effect on the fact finding process.”[87]

The authors quoted from a study in which computer animations had the dual effect of clarifying physical evidence but also biasing verdicts in the direction of the animation. In other words, study participants who witnessed a neutral animation of a man falling to his death at a construction site were more likely to render a verdict consistent with the physical evidence in the case. However, participants who saw a more biased animation – depicting a man losing his balance and falling – were more likely to vote in favour of the plaintiff’s theory of an accidental death even when the physical evidence supported the defendant’s theory that the man jumped.[88]

Clearly, vivid evidence distracts the attention of the trier-of-fact from more cogent, but less vivid, evidence.

Kirker and Mason cited Green v. Lawrence[89] as an example of a crime scene reenactment that was ruled inadmissible because it failed the test of reliability and necessity. Indeed, having found the animation “scientifically unreliable in showing the motion, movement and interaction” between the two subjects, Justice MacInnes seemed to consider the potential for distortion essentially within the context of reliability:

“In my view, the proposed evidence is misleading in the sense that its effect on the trier-of-fact is out of proportion to its reliability.”

However, a matter of at least equal concern is the potential for animated and other vivid evidence, even if scientifically reliable, to distract the trier-of-fact from more cogent but less vivid evidence.

The Court of Appeals of Texas remarked on the danger of vivid evidence distracting jurors from lengthy oral testimony in Lopez v. State[90]:

“While videotape recreations of criminal activities may be acceptable in some jurisdictions, the concept of recreating human events with the use of actors is a course of conduct fraught with danger. The general appearance of an actor, his facial expressions or the slightest gesture whether intended or not may sway a juror who has listened to lengthy testimony. The danger of jurors branded with television images of actors, not testimony, is too great to ascertain. No court instruction could remove highly prejudicial evidence of a re-enacted rape or murder if we establish a precedent.”[91]

The court ruled that there was no necessity for having used the reenactment except to make more vivid the prosecution argument. “This film would constitute an extra witness for the State.” The court envisioned defendants “with ample funds and a flair for the dramatic competing with the State in making their own films for trial.”

“Defendants will soon be shown acting out alibis or affirmative defences.”[92]

David Hennes wrote fifteen years ago that the reason people remember the pictures is that vivid individual examples tend to distract attention from a considerable amount of relevant evidence that is more representative of “the whole”. He cited studies indicating that “all other things being equal, most people are more deeply influenced by one clear, vivid, personal example than by an abundance of statistical data.”[93] Such influence from, for example, a videotaped crime scene reenactment may lead to what Hennes termed “inferential error” because the reenactment has the potential to “dwarf other more probative, yet less vivid, testimony and evidence”.

To focus purely on the potential for inflammation is to ignore the risk recognized in Lopez that demonstrative evidence may diminish or dwarf more cogent evidence. There needs to be much greater judicial scrutiny as regards the use at trial of demonstrative evidence before it may be said with confidence that demonstrative evidence should be treated for the purposes of admissibility and/or use as simply another acceptable, albeit better, method of persuasion.

David Hennes’ analysis was applied by the Ontario Court of Appeal in R. v. MacDonald[94]. The accused was charged with various offenses including aggravated assault with a dangerous weapon after a failed police “takedown”. The accused’s version of events differed from that of the police officers involved in the takedown. The Crown sought to rely on a videotaped reenactment of the Crown version of the takedown based on an amalgam of the evidence of four police officers. The four officers had discussed the incident among themselves before making the video.

The accused objected on the traditional ground that the reenactment was more prejudicial than probative. The trial judge allowed the reenactment to be viewed by the jury. The accused successfully appealed to the Court of Appeal, which ruled that:

“A serious concern with videotaped reenactments, particularly those created without the participation of the accused, is their potential to unfairly influence the jury’s decision-making. Because a video reenactment has an immediate visual impact, jurors may be induced to give it more weight than it deserves and, correspondingly, to discount less compelling or less vivid evidence which is nonetheless more probative of the facts in dispute.”[95]

The Court of Appeal also noted that the danger increases when the videotape depicts not just the undisputed positions of persons and things but one side’s version of disputed facts.[96] In effect, the video becomes an extra witness for the prosecution.[97]

The Court of Appeal quoted Hennes as to the concern over “the high sensory impact of video images and their tendency to remain at the front of the viewer’s mind”.

Beyond Animated Reenactments

If there is a valid concern that evidence with high sensory impact will remain at the front of the viewer’s mind, the concern should not be restricted to animated reenactments.

Nevertheless, in R. v. MacDonald the Court of Appeal declined to enunciate a general principle of judicial caution or special scrutiny. It refused to “lay down rigid rules governing the admissibility of video reenactments” for fear of taking a technological step backward. Instead, the Court applied the traditional approach that whenever prejudicial impact outweighs probative value a video reenactment should not be admitted. Further, “trial judges should at least consider the video’s relevance, its accuracy, its fairness and whether what it portrays can be verified under oath.”[98]

The Court of Appeal also declined to list “necessity” as a disqualifying factor, on the ground that the availability of alternate and less graphic evidence would apply to charts, graphs, diagrams and maps which are routinely admitted into evidence to help the trier-of-fact understand the evidence of a witness. Thus, necessity was to be a factor in the weighing of prejudicial effect versus probative value.[99]

Nevertheless, I suggest that the court’s expressed concern as to the impact of evidence with high sensory impact opens the door to objections to the use of any demonstrative evidence that has high sensory impact. Thus, photographs, diagrams, charts or illustrations with high sensory impact may be objected to as having the potential to stay at the front of the viewer’s mind to the exclusion of more probative evidence.

R. v. MacDonald should not be limited to videotaped reenactments. Nor should it be considered as sanctioning use without careful scrutiny of charts, graphs, diagrams and photographs that may have more subtle, but no less prejudicial, sensory impact.

Reenactments were again considered in R. v. Badgerow.[100] Justice D.J. Gordon considered the admissibility of a Crime Stoppers video reenactment of an assault on a woman who was walking home late at night. Actors portrayed the attacker and the victim.

The Crown sought to tender the video reenactment at trial to give the jury an impression of the area of the attack as it was at the time of the event. Many of the businesses in the area were no longer there, streets had been improved and residential development had taken place on the other side of the street. The Crown argued, in effect, that the triers-of-fact could be transported back to the scene of the attack, arguing that “there is probative value in the video as it provides a picture of the area that is no longer there.”[101]

The defendant, by pre-trial motion, requested an order prohibiting the admission of the video. Counsel argued that the prejudicial effect of the video would be in distracting the jury from their proper fact-finding responsibility. The nature and extent of the attack were among the matters in issue. Lighting was used to highlight the attack and the face of the actor portraying the attacker. Thus, the jury might wrongly infer that the victim could easily identify her attacker. Nor was the video necessary, it was submitted. Maps and aerial photographs could depict the area as it had been.

Justice Gordon applied R. v. MacDonald and disallowed the use of the video reenactment.

“The focus of the video is the actors and the events portrayed. Any benefit to the jury as to observing the area involved is minimal… prejudice, or at least the potential for prejudice is a very real concern… (referring to Hennes’ article as quoted in R. v. MacDonald) “The danger in the use of this video reenactment is that the focus is on the events which may well leave a ‘lasting impression on the jurors’ mental process’. In our jury system, we will never know the impact, if any, resulting from viewing this video.”[102]

Again, the analysis is applicable to any demonstrative evidence and not just crime reenactments. All demonstrative evidence that is not purely illustrative is intended by advocates to leave a “lasting impression” on the trier-of-fact. Are we more capable of ever knowing the “impact” of seeing any type of memorable demonstrative evidence? Is there not as great a need for judicial vigilance as regards all forms of demonstrative evidence in the continuum from the purely illustrative to the highly dramatic?

The Spectrum or Continuum of Evidence and Admissibility

Kirker and Mason in The Dangers in the Use of Demonstrative Evidence in Canadian Civil Litigation[103] argued that demonstrative evidence may be seen as being on a spectrum:

“At one end of the spectrum are the non-substantive demonstrative aids used to assist the judge or jury in understanding the evidence. This evidence is tendered to explain, clarify, or illustrate verbal testimony. Unlike ‘true’ real evidence, it is not intended to speak for itself.

“At the other and most ambitious end of the spectrum is the complex or predictive demonstrative evidence intended to visually demonstrate the results of a mathematical analysis or other available evidence. The analysis can be undertaken to illustrate an expert’s opinion or as the substantive basis for the expert’s conclusion. In either case, the reconstruction purports ‘to have a greater probative value than the accumulation of (the) foundational real evidence without further analysis…’”.[104]

The authors quote Barbara Legate’s proposition that “demonstrative evidence cannot be categorized by any hard and fast rule. Rather it lies on a continuum of purpose and complexity”. According to Legate, if “the purpose is only to illustrate testimony, it is non-substantive. If it is intended to be a substitute for an event in a lawsuit, it is substantive. The greater the accuracy and probity, the more likely it will be received as substantive.”[105]

However, the proposition ignores the potential for inferential error based on cognitive over-reliance. Thus, David Hennes argued, the relevant continuum in relation to demonstrative evidence is “the continuum of decreasing admissibility”.

According to Hennes:

“When the videotaped evidence in a civil trial can be regarded as attenuated or related to a collateral matter, such as in the case of recorded depositions or the scenes of accidents, the videotape’s acceptance level can be considered routine or high. But, as the content of the videotaped evidence moves closer to dramatizing the issues in dispute (such as in the case of reconstruction in civil cases) judicial scrutiny and instances of exclusion increase. Thus, the recognition that courts will apply a heightened standard of review to certain forms of videotaped evidence in both civil and criminal settings serves as a harbinger of the even closer judicial examination that courts confronting the issue have given criminal reenactments.”[106]

Unfair Prejudice and Inferential Error

When are advocacy and/or evidence unfair?

Hennes suggested that “unfair prejudice” has not been easily defined[107]:

“Generally, all evidence presented by an opposing party is in some way prejudicial; therefore, prejudice does not simply mean damage to the opponents’ cause…

“The use of emotion in decision-making is a relevant consideration, though not necessarily the only consideration in measuring unfair prejudice…

“It has been argued that the most compelling and workable definition of unfair prejudice is that by Professor Gold, who quantifies evidence as unfairly prejudicial when it detracts from the accuracy of fact-finding by inducing the jury to commit an inferential error.”[108]

Unfair prejudice has been described as occurring when evidence is employed that causes the trier-of-fact to commit inferential error.[109]

Hennes cited Gold in arguing that inferential error “occurs when the jury incorrectly decides that evidence is probative of an alleged fact or event, when it is in fact not probative of that particular fact.”

Gold’s example was the use of evidence for an irrelevant purpose. For example, the more serious the injury, the greater chance that liability would be imposed.[110]

Guthrie, Rachlinski and Wisterich[111] describe this as “hindsight bias”, to which bias they concluded that judges, as well as jurors, are susceptible. “Knowing the outcome significantly affected judges’ assessments”:

“Table 2, below, shows that judges informed of a particular outcome were much more likely than the other judges to have identified that outcome as the most likely to have occurred….

“Thus, the judges exhibited a predictable hindsight bias; when they learned that a particular outcome had occurred, they were much more likely to identify that outcome as the most likely to have occurred.

“When predicting the likelihood of something after the fact, judges cannot help but rely on facts that were unavailable before the fact. Judges’ susceptibility to the hindsight bias is troubling because judges are frequently expected to suppress their knowledge of some set of facts before making decisions…when assessing the reasonableness of precautions taken by a tort defendant, judges are expected to disregard their knowledge of the plaintiff’s ensuing injury. Although we did not test the operation of the hindsight bias on judicial decision making in these circumstances, our results suggest the judges are vulnerable to the influence of the hindsight bias in these and other contexts.”[112]

Gold thus drew a distinction between demonstrative evidence that appeals to emotion and demonstrative evidence that induces inferential error:

“The prejudicial impact of photographs of a victim’s gory remains derives from the potential such vivid evidence has to so dominate the minds of jurors that they exaggerate its probativeness. The fact that evidence of this type may evoke an emotional reaction from the jury does not necessarily make it prejudicial. There may be nothing wrong with shocking a jury with the repulsiveness of a crime, as long as the impression made by the evidence in question is commensurate with its probative worth.”


“The juror ideally should ascribe to an item of evidence only the probative value that the item deserves…giving the item undue weight would constitute an inferential error.”[113]

Thus, scientific evidence often poses the risk of inducing inferential error because jurors may overestimate the objectivity and certainty of scientific testimony.[114]

Inferential error becomes unfairly prejudicial when opposing counsel is unable to expose the error or otherwise negate its harmful effects. Exposing this form of error is a difficult, if not impossible task, because the inferential error often distorts the truth in such a subtle way that its dangers cannot be explained to the jury.[115]

In an American case, the court disallowed a videotape reenactment of an incident leading to a defendant’s arrest to be introduced into evidence. The Court reasoned that the videotaped reenactment violated “basic fairness” because “seeing the events depicted exactly as the State’s witnesses said they happened is bound to affect the jury out of all proportion to its value as evidence.”[116]


Kirker and Mason wrote that “charts, maps and diagrams are the simple tools routinely introduced to assist the decision-maker to better understand verbal testimony.”[117]

However, even as to this apparently innocuous demonstrative evidence bias, distortion and resultant error may be subtly induced in ways that are probably undetectable by even a highly-trained and discerning judicial eye.

Graphic design is an art with which many lawyers are not familiar. One author who advocated the use of graphic design during trials wrote that “small changes, which an attorney may consider irrelevant”, make a large difference in the readability and persuasiveness of a graphic:

“Color is Important. Colors have meaning. Make sure you choose them appropriately. Our language is full of meanings associated with color: A person red with anger; green with envy; a bit of blue today; this is a black day for all of us; he’s just plain yellow. A plaintiff may well use red in a damage chart. A defendant would be unlikely to. Choose your colors carefully, yet use them sparingly. Generally, black print on which background using color (particularly red) for emphasis is well accepted. Some conventional wisdom:

a) Use darker colors with more educated persons (add black, making reds burgundy, etc.);

b) Greens hold attention longer, are more calming, and are associated with money;

c) Browns are usually uninviting, but peach allegedly invites giving;

d) Red arouses emotions;

e) Blue denotes calm truth, experience, and is the most widely accepted color;…”[118]

Graphic artists can visually communicate emotions that may not be warranted on a neutral, impartial weighing of the evidence. Changes in colour may communicate anger (red), envy (green) or truth (blue).

“Using color helps reinforce themes. To many people, green conveys an image of safety, while red suggests danger. To show that a defendant doctor ‘ran a medical red light,’ consider a graphic depiction of a stoplight, where green represents a safe condition and red the patient’s clinical presentation.

“Medical risk factors can be highlighted with a red flag instead of bullets or numbers. For example, to illustrate a plaintiff’s risk factors for pulmonary embolism, the lawyer might put a list of the words ‘nausea, dyspnea, fatigue, obesity, and syncope’ under the heading ‘Charlotte’s Risk Factors fro Pulmonary Embolism.’ But a chart titled ‘Ignored Red Flags for Charlotte’s Pulmonary Embolism,’ with red flags pointing to the listed risk factors, would pack more visual punch.”[119]

If attorneys miss the persuasiveness – fair or unfair – of demonstrative evidence such as coloured graphics, trial judges and jurors may similarly be completely unaware that they are being persuaded or becoming predisposed to a particular result by a communication tool rather than by evidence.

Subtly-induced bias is not limited to colour graphics. In his 2002 article on the use and abuse of graphics[120] Alan Davis warned “never take graphs for granted”. Pointing out that approximately one-quarter of the graphs in the annual reports of large corporations around the world are seriously flawed, he suggested that since distortion tends to favour the reporting entity an intentional bias is indicated.[121]

As to the potential to create bias by distracting the trier-of-fact, Davis warned that:

“Graphs can speak loudly, not just when being displayed, but from the viewer’s memory, so getting them right, and not letting the other side get them wrong, is important. Impressions made by graphs may be difficult to dislodge.”[122]

Bias-inducing impressions include distortion such as when the “pies” in a pie-chart are not drawn to scale. The visual impression that is created is that a proportion is larger or smaller than it actually is. Another bias-inducing graph technique is to use non-zero baselines. These alter perceived proportions particularly as to increasing or decreasing trends such as post-injury decline in income. Trends can be made to appear more dramatic than is actually the case.[123]

Davis wrote concerning advocacy that:

“In trying to support a particular position, litigators may be tempted to present graphs that make their claims more dramatic… (whether or not to do so) would involve assessments not only of the graph in question but of the predisposition of the court and the extent of any damage from trying to ‘push the envelope’ too far.”[124]

Regarding photographs, Roger Oatley wrote for the 2003 Law Society of Upper Canada Special Lectures[125] that “one abuse is the variation or enhancement of photographs” by scanning and computer-generated alteration, cropping so as to encourage the viewer to focus on a particular aspect of a scene and filtering of colours and enhancement of contrast.

“There is an even simpler way in which photographs have been misleading us for years without our knowing. A skilled photographer will tell you that a telephoto lens makes objects appear closer. In so doing, the lens compresses distances in a way that distorts reality. Similarly, the wide-angle lens makes objects appear farther away and creates a misleading appearance that distances are greater. Police photographs are usually taken with a wide angle lens…

“In the motor vehicle cases that consume my practice, the potential for abuse requires little imagination. Where a wide angle photograph portrays the subject at a considerable distance, the viewer can be left with the mistaken impression that an individual would have had ample time to perceive and react to any given situation. Alternatively, where the telephoto lens portrays the subject as very close to the viewer, the viewer might be inclined to excuse a failure to react in time. If distorted photographs are used as the basis of a computer animation, the resulting distortion can be even more dramatic and even harder to detect.”[126]

Oatley suggested that there is nothing inherently abusive about the enhancement of photographs or the use of telephoto or wide angle lenses so long as the technique is “declared, clarified and understood so that it does not mislead”[127]. However, declarations and clarifications may have little or no effect if no one is listening after seeing the image.

Hennes argues that the dangers of inferential error are particularly profound because the error is often subtle, occurring when the jury diligently pursues the issues it is charged with deciding.

“Inferential error becomes ‘unfairly prejudicial’ when opposing counsel is unable to expose the error or otherwise negate its harmful effects. Exposing this form of error is a difficult, if not impossible task, because the inferential error often ‘distorts the truth in such a subtle way that its dangers cannot be explained to the jury’.”[128]

What of a limiting instruction from the judge to the jury? According to Gregory Jones[129]:

“Limiting instructions theoretically offer some protection against confusion, but in light of the difficulty that courts have had in grappling with this ‘demonstration’/‘re-creation’ distinction, it is unrealistic to assume the average juror will fully appreciate the subtleties of the distinction. Furthermore, as a practical matter it is doubtful that the juror will actually remember such a distinction (or admonitions contained in any limiting instruction) when, after what may be days or weeks of intervening evidence, the juror finally enters the jury room to evaluate all the evidence and decide the case. After all, the memory of a vivid videograhic depiction may outlast any recollection of the warning contained in an oral limiting instruction.”[130]

No One Is Listening – They Can See That O.J. Simpson’s Bloody Glove Does Not Fit

People remember more than pictures. They remember demonstrations and rhyming couplets in preference to more cogent evidence.

O.J. Simpson was tried for, and acquitted of, a double murder.

It may be that fewer people remember the names of the victims than remember an item of real evidence – the “bloody glove” – and the in-court demonstration that prompted O.J. Simpson’s lawyer to argue to the jury: “If it doesn’t fit, you must acquit.”

O.J. Simpson never testified in his own defence. Or did he?

O.J. Simpson tried on a bloody glove. Prosecution witnesses testified that it was found at the crime scene. As O.J. Simpson contorted his face in his apparently futile effort to make the glove fit he was heard by some to say “too small”. He said no more in his own defence and some never heard the words. But the members of the jury saw something memorable.

Prosecutor Marcia Clark wrote of the demonstration that after it was over she knew that the prosecution had lost the case even though the prosecution planned to, and did, call evidence to explain why the demonstration was flawed and should be given no weight by the jury.


Vincent Bugliosi set the stage in his book Outrage: The Five Reasons Why O.J. Simpson Got Away with Murder[132]:

“The glove demonstration, of course, we all know about. Many feel it was the pivotal point in the trial, from which the prosecution never recovered….

“ ‘Too tight’ (some newspapers reported the words were ‘they don’t fit’), Simpson said loudly enough for the jury to hear as he seemingly struggled to tug the leather gloves over his broad palms.

“In Madam Foreman, Simpson juror Carrie Bess writes: ‘When I saw that demonstration, I thought, why in the hell didn’t the prosecution try that glove on somebody else that had the same size hands as O.J. before they allowed him to get out here and do this? I was sick when I saw they didn’t fit because I just thought for sure that they were going to fit.’

“It is, of course, astonishing that the prosecutors would ask Simpson to try on, before the jury, the left-hand glove found at the murder scene and its right-hand mate found on the grounds of Simpson’s Rockingham estate without knowing, for sure, they would fit. You simply don’t take an enormous gamble like that at a trial, particularly when there is no pressing need to.”

Bugliosi blamed lead prosecutor Marcia Clark for the demonstration.

“But whoever is to blame, it was a disaster, and although the prosecutors put in evidence to mitigate the damage (the evidence the gloves had shrunk, though this was disputed by the defence; the new gloves, which were the same as the evidence gloves in style, make, and size, were eventually used in a demonstration, and fit Simpson well, etc.), the vivid memory etched in the jury’s mind was that the gloves they knew the killer used did not fit Simpson comfortably – he was not able to extend his fingers fully into the tips of the gloves. ‘In plain English,’ Simpson juror Brenda Miran told reporters after the verdict, ‘the gloves didn’t fit.’

“But should these very same gloves have fit Simpson properly? Perhaps forgetting he was still on stage, Simpson did in fact slip these same gloves off his hands quite easily, a fact which Marcia Clark noted to the jury in her final summation.”[133]

Mr. Simpson’s lawyer, Johnny Cochrane, argued to the jury: “if it doesn’t fit, you must acquit”. Bugliosi suggested that this singsong, childlike rhyme was suggested to Mr. Cochrane by co-counsel Gerald Uelman.[134]

“And like trained Mynah birds, two jurors after the trial informed the media, ‘if it doesn’t fit, you must acquit.’”[135]

Marcia Clark has clarified that the prosecution had planned for Mr. Simpson to try on duplicate gloves. They had been requested from the glove manufacturer “just like the ones found at the crime scene to try on Simpson when the time was right.”[136] However, when the supposed duplicates had arrived they were not the gloves that were contemplated. Co-prosecutor Chris Darden wanted the demonstration to proceed and so after the gloves were tried on by a person whose hands were “at least as big as Simpson’s”[137] the demonstration took place.

Marcia Clark has blamed Chris Darden entirely for what ensued:

“I turned to Chris. ‘Don’t do it. I’m warning you.’

“‘ We’ve got to do it,’ he insisted.

“‘Why won’t you fucking listen to me. This is a trap!’ My voice was hoarse with tension and anger.

“‘This is my witness,’ he snapped. ‘And I say we have to put those gloves on him now before they do!’

“I couldn’t dissuade him.”[138]

Ms. Clark admitted that the demonstration was a disaster:

“Then Johnny and one of the sheriff’s deputies escorted Simpson over to the Jury box, where Simpson began pulling it on. He grimaced and mugged like Cinderella’s stepsister trying to get into that glove.

“He got it only part of the way up his wrist.

“Chris handed him the right glove. Same performance.

“Simpson smiled broadly and displayed his mitts to the jury – and to the camera – as though he were holding up the ball at the goal line. Can you believe this? Here is Simpson wearing gloves splattered with his murdered ex-wife’s blood and he’s grinning ear to ear. Any normal person in these circumstances would cringe.

“I felt like dying…

“Chris held up valiantly. He had Simpson pick up one of the felt-tipped pens on counsel’s table and demonstrate how he could have held a knife. He then had Simpson make stabbing motions. It was a brave recovery. I gave him credit for that.

“When the demonstration was finally over, Simpson casually snapped the gloves off. And I thought to myself, if they were so hard to get on, why are they so easy to get off, Sparky?…

“I looked down at the bloody, weathered leather, and I said to myself, that’s it, we just lost the case.”[139]

Christopher Darden admitted that the demonstration was his idea.[140]

“My heart was pounding and my mouth was dry, but someone had to do this. Someone had to stop the games these defence lawyers were playing and just put the damned gloves on his hands.

“I gave him the left glove, the leather stiff and cold in my hand. Asshole was shaking. I watched his hands closely. His fingers seemed cocked and it was apparent he wasn’t really trying to pull it on.

“‘Your Honour,’ I said sarcastically, ‘apparently Mr. Simpson seems to be having a problem putting on his glove.’

“He was bullshitting and I hoped everyone could see that, hoped the jury could see it. But as I glanced quickly around the courtroom, I saw that everyone else was staring at his hands and not his face.”[141]

Darden wrote in his book on the trial that he called evidence to explain away the demonstration that had failed:

“I had Simpson make a fist and hold a pen before he took the gloves off to show that he could have wielded a knife in the tight gloves. When Richard Rubin got back on the witness stand, I asked if the latex glove would’ve affected the fit of the leather gloves. I asked Rubin if the gloves should have fit Simpson’s hands and he said yes.

“‘At one point in time,’ Rubin said, ‘those gloves would be actually, I think, large on Mr. Simpson’s hand.’

“In the coming days, we brought in experts to testify that the gloves could’ve shrunk. We had Simpson try on another pair of the same kind of gloves without latex underneath, and they fit fine.

“Sixty-one per cent of people polled said they thought the gloves had actually fit. More than even the ice cream defence, the glove experiment brought letters from people who offered explanations for what had happened. On his television program, Rush Limbaugh used a pointer to show that Simpson hadn’t pulled the latex gloves all the way onto his hands, his knuckles showing up in the latex well below the fingers of the gloves and bunching up under the leather gloves.

“But I knew what the damage truly was. People ask me now would I do it again. No. Of course not. I should have taken into account shrinkage and the defence team’s trickery. But, while I wouldn’t do it again, I know those are his gloves. I look at the photograph in the newspaper of him smiling in front of the jury and I see Marcia in the background, a look of disgust on her face. Not for him, for me.”[142]

The vivid impact of the demonstration was fully explained away. Yet, it was the vivid impact that the jurors remembered and it is the demonstration, flawed as it was, that is remembered. “If it doesn’t fit, you must acquit”, Johnny Cochrane argued and the jury agreed, notwithstanding far more relevant and probative evidence called by Christopher Darden that before shrinkage caused by blood the gloves would actually have been large on Mr. Simpson’s hand.

In the race between vivid and cogent, vivid wins.

Pit Bulls Are Vicious[143]

The December 29, 2008 edition of Sports Illustrated included an article on pit bull dogs that had been trained to kill by former Atlanta Falcon quarterback Michael Vick.

A non-menacing dog, at least in appearance, was shown on the cover. The dog is named Sweet Jasmine, and was described as a pit bull “rescued” from Michael Vick’s property. The dog was said to have “found a happy home”.

The theme of the December 2008 Sports Illustrated article was that pit bulls have an unfair reputation as killers. According to the article’s author, pit bulls are unusual, but not inherently vicious.

“‘A pit bull is like a Porsche. It’s a finely tuned, highly muscled athlete,’…and just like you wouldn’t give a Porsche to a sixteen-year-old, you don’t want just anyone to own a pit bull. It should be someone who has experience with dogs and is willing to spend the time, because with training and proper socialization, you will get the most out of them as pets.”[144]

According to the author of the more recent article on pit bull dogs:[145]

“The pit bull’s p.r. mess can be likened to a lot of teens driving Porsches – accidents waiting to happen. Too many dogs were irresponsibly bred, encouraged to be aggressive or put in situations in which they could not restrain themselves, and pit bull maulings became the equivalent of land-based shark attacks, guaranteeing a flush of screaming headlines and urban mythology. Some contend that this hysteria reached its apex with a 1987 Sports Illustrated cover that featured a snarling pit bull below the headline BEWARE OF THIS DOG.”

“Despite the more balanced article inside, which was occasioned by a series of attacks by pit bulls, the cover cemented the dog’s badass cred, and as rappers affected the gangster ethos, pit bulls became cool. Suddenly, any thug or wannabe thug knew what kind of dog to own. Many of these people didn’t know how to train or socialize or control the dogs, and the cycle fed itself.”[146]

A cover photograph of a snarling pit-bull had, in the author’s opinion, far greater impact than the “more balanced article inside”.

Should the Trial Judge Decide?

Kirker and Mason cited R. v. Mohan as confirming that trial judges have the discretion to exclude relevant evidence if it would have an unfair effect on the fact-finding process.[147]

However, Legate suggested that the court’s discretion may be exercized only if it is of the view that probative value is outweighed by prejudicial effect, including fairness, and that prejudicial effect is considered only when probative value is thought to be slight.[148]

In Draper v. Jacklyn, which Legate cited as leading authority on photographic evidence, Justice Spence acknowledged that weighing probative value against prejudicial effect is “always one which is difficult for the trial judge” and is “essentially a decision in which the trial judge must exercise his own carefully considered personal discretion”.[149]

If the discretion is personal and no more scientific than “carefully considered”, why must it be the trial judge who rules? Indeed, if viewing vivid evidence may leave a lasting but unwarranted impression on the trial judge, should another judge not rule on the issue of admissibility?

Obliging the trial judge to make such ruling appears to be based on the premise that judges, unlike jurors, are not vulnerable to the prejudicial effect or potential to mislead of certain evidence.

Kirker and Mason quoted this remark from Sopinka J. in Mohan: “…or if it is misleading in the sense that its effect on the trier of fact, particularly a jury…”.[150]

The authors also quote this from Justice C.D.A. McKinnon in Jenkyns v. Kassam:

“Generally speaking, the admissibility of demonstrative evidence is subject to less strict rules in a judge alone trial than in a jury trial. This was recognized by the authors of The Law of Evidence in Canada, namely the late Justice John Sopinka, Mr. Justice Lederman and now Mr. Justice Bryant… ‘people today because of their exposure to television and motion pictures can be expected to be much less sensitive to graphic displays of injuries than average nineteenth or early twentieth century citizens’… This is particularly true of graphic and sometimes shocking photographs or videotapes, which is not the issue in our case. But generally the fear of prejudice is not as great in a non-jury as in a jury trial, and I think the authors have acknowledged this commonsense proposition.”[151]

There are problems with this “commonsense” proposition. As Justice McKinnon noted, the issue with which he was confronted was not that of the graphic photograph, which was the subject of the text writers’ comment. Justice McKinnon cited no reliable, or any, scientific basis for assuming that modern jurors are less sensitive to graphic displays. Justice McKinnon also made no mention of the potential that modern jurors are just as vulnerable to cognitive error caused by memorable – even if not graphic – demonstrative evidence.

In other words, the commonsense proposition seems to be entirely without foundation except that it was the opinion or belief of the particular trial judge ruling on the issue.

Finally, and as significantly, Justice McKinnon gave no apparent consideration to the possibility that judges are also vulnerable, albeit perhaps to a lesser degree, to cognitive error induced by demonstrative evidence such that the trial judge should not be the judge ruling on the admissibility of such evidence.

Kirker and Mason relied on Jenkyns to suggest that “when dealing with a jury, the danger of prejudice is heightened.” They quoted from Kassin and Dunn’s previously referred-to finding that computer animations had the dual effect of clarifying physical evidence but, at the same time, biasing verdicts in the direction of the animation.[152]

The issue is whether the concern as to such induced error is limited to jurors. For if it is not, should trial judges not also be protected from viewing potentially bias-inducing material? Put another way, should trial judges, sitting with a jury or alone, be called upon to subject such evidence to the special scrutiny required in relation to such evidence or should such scrutiny occur before the trial judge takes charge of the relevant and admissible evidence at trial?

I suggest the latter if there is any concern that judges are not immune to the potentially biasing or error-inducing effect of vivid, memorable, demonstrative evidence.

Guthrie, Rachlinski and Wisterich[153] noted that people fall prey to cognitive illusions that produce systemic errors in judgment and that judges are no exception:

“Even though judges are experienced, well-trained and highly-motivated decision-makers… (and) although the judges in our study appeared somewhat less susceptible to two of these illusions… we found that each of the five illusions we tested had a significant impact on judicial decision-making. Judges, it seems, are human. Like the rest of us, their judgment is affected by cognitive illusions that can produce systemic errors in judgment.”[154]

In a study of 167 U.S. federal magistrates, the authors found that judges are vulnerable to cognitive illusions caused by anchoring (making estimates based on irrelevant starting points), framing (treating economically equivalent gains and losses differently), hindsight bias (perceiving past events to have been more predictable than they actually were), the representative heuristic (ignoring important background statistical information in favour of individuating information) and egocentric biases (overestimating one’s own abilities).[155]

Morell Mullins, Sr., defined “heuristics” as “mental shortcuts and rules of thumb”. He commented:

“Unfortunately, biases and errors are inseparable from heuristics. To use imprecise ‘rules of thumb’ in making decisions under conditions of complexity and uncertainty is to invite biases and errors stemming from the decisions makers’ own psychological backgrounds and tendencies. In fact, the ‘literature’ on heuristics understandably emphasizes the biases and errors more than the basic ‘heuristics’ themselves….

“To use a more familiar term, a major bias or source of error in using the ‘representativeness’ heuristic is stereotyping.”[156]

Thus, and with respect, Justice McKinnon’s previously-quoted remarks in Jenkyns may have been nothing more than the product of egocentric bias rather than “commonsense”.

The authors found, for example, that although judges were less susceptible than laypersons to making categorical judgments based on irrelevant factors they were still vulnerable to doing so on the basis of whether the evidence conforms to their pre-conceived notions.

Such pre-conceived notions, or “representative heuristic” were described in Sanchirico’s article on cognitive error as inducing fact-finders to place too much weight on whether the evidence matched their mental picture of, for example, negligent behaviour, and too little weight on the base frequency of such behaviour in the population.[157]

Guthrie et al. noted as regards the representative heuristic that:

“When the evidence appears representative, or similar to, the category (for example, defendant is nervous and shifty), people judge the likelihood that the evidence is a product of that category as high (for example, evidence of guilt). When the evidence being analyzed does not resemble the category (for example, defendant appears at ease), people judge the likelihood that the evidence is a product of that category as low (for example, evidence of innocence). Psychologists refer to this phenomenon as the ‘representativeness heuristic’.”

The authors argued that although the representativeness heuristic is useful, it can lead people to discount relevant statistical information in favour of that which is vivid and, hence, compelling:

“Psychological research does not clearly indicate why people ignore base rates and rely on the representativeness heuristic when making categorical judgments. Individuating evidence is more salient and vivid and hence more compelling than pallid base-rate statistics. Also, because relevant statistical evidence is commonly unavailable, it might simply be more efficient for people to focus on individuating evidence.

“What is clear, however, is that excess reliance on the representativeness heuristic leads people to commit a variety of decision-making errors. In legal decision-making, for example, the failure to attend to base rates can induce a troublesome problem known as the ‘inverse fallacy’. The inverse fallacy refers to the tendency to treat the probability of a hypothesis given the evidence (for example, the probability that a defendant was negligent given that a plaintiff was injured) as the same as, or close to, the probability of the evidence given the hypothesis (for example, the probability that the plaintiff would be injured if the defendant were negligent).”[158]

The authors’ testing indicated that although judges performed better than other groups, 40% of the judges who responded fell into the trap that the representativeness heuristic creates.

The authors also found that judges were vulnerable to anchoring when obliged to rule on a motion to dismiss a personal injury action on the ground that it does not meet the jurisdictional minimum for a diversity case of $75,000.00.

“Ruling on the motion might have caused the judges to consider the possibility that the true damages in the case were exceptionally low.”[159]

If judges are vulnerable to cognitive error in these respects, particularly after having had to rule on a legal issue, there would seem to be a valid concern that a judge who has to rule on the admissibility of demonstrative evidence might be induced to make cognitive error even if the ruling is that the evidence will not be admissible at trial.

To paraphrase Justice Gordon’s concern in Badgerow, the danger is that the judge may be left with a lasting impression of which we will never know the impact.

Guthrie et al. wrote of this “important advantage of a jury trial”:

“it creates a mechanism for keeping potentially misleading information away from the fact-finder. A judge will always know about subsequent remedial measures and statutory damage caps, whereas the information can be kept from juries. Generally, when the only means of avoiding the effect of a cognitive illusion is to restrict access to the information that triggers it, a jury trial has a substantial advantage over a bench trial.”[160]

If it is accepted that jurors should not have access to potentially misleading information to minimize the possibility of cognitive illusion and if Guthrie et al. are correct that judges are also vulnerable to such illusion, then should the trial judge, particularly if sitting alone, not also be protected from potentially misleading information, especially information that may leave a lasting impression?

Judges sitting alone can also be protected from possible cognitive illusion in a judge if a different judge rules before trial as to what, if any, demonstrative evidence is to be allowed at trial. Once the ruling is made before trial, judge and jurors alike, if there are jurors, are protected from any access to information that may induce cognitive error.

Is it feasible to have such rulings at the pre-trial stage? There is no reason why not. Rulings as to demonstrative and expert evidence, for example, could be made at criminal pre-trials and preliminary inquiry “focus hearings” conducted pursuant to the Criminal Code and described in Judicial Case Management section of the Lesage- Code Report of the Review of Large and Complex Criminal Case Procedures.[161]

The authors describe amendments to the Criminal Code as providing for a hearing to identify the issues, witnesses and any other matters that would promote a fair and expeditious hearing.[162]

The authors envision pre-trial and focus hearing judges making binding orders that “manage and shape” the trial or preliminary inquiry, as the case may be.[163]

Legate urged expansion of the limited scope of trial management hearings. She urged involvement of the trial judge so that rulings on admissibility could be obtained in advance.[164]

However, there is no need for the trial judge to have such involvement. Included in the Osborne Report “Recommendations for Reform” is the following regarding Ontario’s Rules of Civil Procedure:

“Amend Rule 50 to prescribe the dual purpose of a pre-trial conference: to discuss settlement of some or all of the issues, and to obtain any necessary orders and directions to ensure that the action is ready for trial and the trial proceeds in an orderly and efficient manner.”[165]

In 1998, the proposed model rules governing the admissibility in Maryland of computer-generated evidence provided for pre-trial objections where one party asserted that the probative value of evidence was substantially outweighed by the risk of unfair prejudice, confusion of the jury, or undue consumption of trial time. The benefit was seen as providing counsel with an opportunity to object to “an outrageously prejudicial computer animation” without waiting for a mid-trial relevancy ruling.[166] As with other portions of the contemplated pre-trial order, the court’s pre-trial ruling was envisioned as controlling the subsequent course of the action. The record of the objection for appeal purposes has been made during the pre-trial hearing. If the evidence is excluded before trial, the trial proceeds without considering the evidence but the proponent has made its record for appeal.

Young and Susser have suggested that Michigan lawyers file a motion in limine for approval of a demonstrative exhibit before trial.

“Such a motion can address the logistics of the necessary equipment in the court room and the relevance of the evidence. The motion also may suggest limiting instructions – for example, that the exhibit is not intended to be a precise simulation but is offered only to illustrate certain general principles. Seeking prior approval will stymie opposing counsel’s argument for prejudice and enable counsel to make alternative plans if approval is withheld.”[167]

Currently, the pre-trial in Ontario is settlement oriented.[168] If the pre-trial judge is to do other than “explore opportunities for settling all or part of the action”[169] trial coordinators will have to allow pre-trial judges more than the currently-allotted 30 minutes to effectively conduct and conclude each of the dual purposes of the new, expanded pre-trial.


Jessica Silbey started her article on films as evidence by juxtaposing quotes that confirm that the tension between admission and exclusion of vivid demonstrative evidence is not recent although admission is becoming more accepted:

From 1942 – “The errors here involved…permitting the plaintiff to convert the court into a ‘movie’ picture theater….Doubtless the show was highly entertaining to the jury, but entertainment of the jury is no function of a trial.” Hadrian et al v. Milwaukee Electric Railway & Transport Co., 1 N.W.2d 755, 758 (Wis. 1942)

From 1977 – “The films illustrate, better than words, the impact the injury has had on the plaintiff’s life in terms of pain and suffering and loss of enjoyment of life. While the scenes are unpleasant, so is the plaintiff’s injury.” Grimes v. Employers Mutual Liability Ins. Co., 73 F.R.D. 607, 610 (D. Ala. 1977)[170]

The process continues. Demonstrative evidence is not only here to stay its use as a tool of advocacy is increasing as technological developments make its production cheaper and more accessible.

However, I offer one last note of caution:

“During the past fifteen years judicial responses to proffered videographic evidence have closed some of the gap and ushered in a relatively more relaxed courtroom atmosphere toward admissibility. This can be seen not only in the promulgation of rules that have facilitated the use of videotaped depositions, but also in wider use of such foundational innovations as the ‘silent witness’ theory, and in greater receptivity towards the admission of videographic accident reconstructions and day-in-the-life documentaries.

“The irony is that, as courts have become less apprehensive about the technology – and particularly less wary about the prospects for fabrication – the technology itself has mutated. The emergence of digital technology has breathed new life into concerns about the prospects of manipulation and outright fabrication of videographic evidence. While this potential should not cast a pall over the entire field of videographic authentication, it does call for some degree of caution.”[171]

Although my concern is not as to fabrication of evidence but, rather, as to distortion of fact-finding, the need for caution remains as digital technology enables the subtle manipulation of evidence at the desk-top.

My concern is as much personal in origin as it is based on research.

As a child, I saw a film of an animal writhing in agony as it tried to free its leg from a trapper’s iron-toothed leg trap.

No rational argument in favour of continuing to allow leg hold traps could ever rid my mind of the image of that animal. I became and remain closed-minded on the issue.

I do not say that I am right. I say only that I am not unique – or probably even unusual – in my vulnerability to being overwhelmed by the vivid image.

As I finish this paper, the annual seal hunt has begun in Eastern Canada. The internet is again filled with postings, including that of the United States Humane Society, urging that the hunt be discontinued.

Videos are available that show baby seals being dragged from mothers and clubbed to death before being skinned. There is a YouTube video taken during the 2008 hunt. The numerous web sites urging that the seal hunt be banned invariably lead off with a photograph of a hunter swinging his wooden club over his helpless prey. The words that follow hardly matter.

Contrast the images to the benign, almost “way of life”, photographs on the Fisheries and Oceans Canada website. Under images of small fishing vessels moored in a rural harbour and of a fisheries department official on the ice with his binoculars – obviously ensuring that the matter proceeds strictly in accordance with government regulations – the government website promises “a factual and balanced account” of the annual seal hunt. Obviously, no graphic images of hunters standing over baby seals are presented. Readers should not be distracted, nor should they have their minds closed to persuasion, before they read the “balanced” account because people remember the pictures.

Pending further – or any – study of the impact of graphic images on contemporary judge and juror alike, I suggest that it borders on irresponsible to rely exclusively on assumptions based on nothing more than “common sense” in deciding that persons brought up in the television age can be expected to be less vulnerable to cognitive error induced by graphic or vivid images.

I finish by echoing Morell Mullins Sr.’s wish to emphasize that “insights from psychology and decision theory are not fool-proof” and “are especially fragile in the hands of a legal academic…who lacks systematic education in those disciplines”. However, I also suggest that Mullins very wisely continued by suggesting that although few lawyers and judges are qualified scientists “all of us can use insights from more scientific disciplines to study and think about”[172] issues involved in the administration of justice. Mullins’ issue was statutory interpretation. Mine is demonstrative evidence and I urge at least further study that should result in more informed “thinking about” the impact of demonstrative evidence to dominate the evidentiary scene and destroy the search for truth.