Attorneys frequently seek to have admitted into evidence the results of demonstrations or experiments, whether performed pre-trial or to be performed in the courtroom, to prove that a claimed event, occurrence or condition, relevant to a contested issue in the trial, did or did not happen, or would or would not happen. Not only is such evidence a powerful means of proving or disproving the claimed event, occurrence or condition, but also, as former Appellate Division Justice Helen Freedman has noted, such evidence "enliven[s] trial proceedings and are effective tools for education both the court and jury." Freedman, New York Objections §13:110.

Notably, the New York courts have historically recognized the admissibility of the results of demonstrations and experiments. Thus, in 1908 the Fourth Department ruled that such evidence is "admissible and commonly resorted to … as evidence that an alleged result would or would not follow from the conditions proven." People v. Fiori, 123 App. Div. 174, 185 (4th Dept. 1908). Whether this evidence will in fact be admitted, the courts have consistently stated, lies within the discretion of the trial subject to be exercised depending on the facts and circumstances of each case.

This discretion is not, however, absolute. Guided by the principle that if evidence has "any tendency to exaggerate any of the true features which are sought to be proved," the trial court may exercise its discretion to reject the evidence. Boyarsky v. Zimmerman Corp., 240 App. Div. 361, 362 (2d Dept. 1934). Expressed differently, such evidence may be admitted in the trial court's discretion when it "tends to enlighten rather than to mislead the jury." Goldner v. Kemper Ins. Co., 152 A.D.2d 936, 937 (4th Dept. 1989). All of this means that admissibility of the results of demonstrations and experiments turns upon the establishment of a proper foundation for their admission into evidence. This column will explore the nature of this required foundation.

Before addressing the foundation issue, it is worthwhile to initially note the courts have not limited admissibility of the results of demonstrations and experiments to defined categories of subject matter or otherwise precluded admissibility for certain or specified demonstrations or experiments. Rather, the subject matter of demonstrations and experiments in both civil and criminal actions is virtually unlimited. Thus, for example, in Matter of Eighth Jud. Dist. Asbestos Litig., 32 A.D.3d 1268 (4th Dept. 2006), revd. on other grounds, 8 N.Y.3d 717 (2007), the Fourth Department in an asbestos case upheld the admission into evidence of a videotape, prepared by one of plaintiff's experts, depicting asbestos dust production caused by gasket production. In Washington v. Long Is. R.R. Co., 13 A.D.2d 710 (2d Dept. 1961), an action to recover for personal injuries sustained when plaintiff was struck by defendant's train after he had fallen to tracks from a passenger platform, the Second Department held the defendant should have been permitted to show the results of experiments as to the distances in which a train could be stopped when confronting an unexpected situation. In Goldner, a fire loss subrogation action involving a suspected arson, the Fourth Department held the trial court properly admitted the result of experiments which showed that, when placed in direct contact with a cotton bedspread, a lighted bulb would not cause that material to break into open flame until an appreciable period of time lapsed. In Thomas v. Central Greyhound Lines, 6 A.D.2d 649 (1st Dept. 1958), a personal injury action seeking to recover damages sustained as a result of a collision between defendant's bus and a truck, the First Department held the trial court should have admitted, for purposes of impeaching the testimony of plaintiff as to what he observed right before the accident, the results of an experiment establishing the angle of his vision to show his inability, by reason of physical circumstances, to see what he claimed to see. In People v. Birenbaum, 301 A.D.2d (1st Dept. 2002), a murder prosecution, the First Department held that a videotaped demonstration depicting how a pilot can, without any assistance, load a 110-pound body onto a Cessna 172 airplane, fly it over the ocean, and discard it overboard was properly admitted. A wide range of demonstrations and experiments, for sure and for different purposes, but they have a common thread, namely, a proper foundation for their admissibility was established.

The governing standard for the required foundation for the admissibility of the results of demonstrations and experiments is readily stated. Such results are admissible upon a factual showing that the conditions under which the demonstrations or experiments were performed are substantially the same, though not necessarily identical, as those existing at the time of the event, occurrence or condition to which they relate. See Barker & Alexander, Evidence in New York State and Federal Courts (2d ed.) Experiments and Demonstrations §11:18 (collecting authority). It is that identicality or substantiality between the conditions that makes the results achieved by the demonstration or experiment relevant. Suffice it to say, it is error to admit into evidence results of a demonstration or experiment without a showing that the demonstration or experiment was conducted under identical or substantially similar conditions to those in issue. See Weinstein v. Daman, 132 A.D.2d 547, 549 (2d Dept. 1987). Demonstrations and experiments must therefore be conducted upon a basis that replicates as much as possible the event, occurrence, or condition that they are seeking to prove or disprove.

Of note, a variation in conditions or circumstances affects the weight to be given to the results but is not a basis for their exclusion. The trial court is vested with broad discretion with respect to the question of the similarity of conditions. In this regard, it is not error as a matter of law for the court, when dissimilarities are present, "to determine that a party's legitimate interest could be sufficiently protected by affording [the party's] counsel unrestricted opportunity for cross-examination." Uss v. Town of Oyster Bay, 37 N.Y.2d 639, 641 (1975).

The Court of Appeals decision in Uss is instructive. In Uss, the plaintiff was allegedly injured when a street sign, mounted atop a metal pole, fell off the pole, striking plaintiff, when his companion struck the pole with his hand. The trial court permitted defense counsel during counsel's direct examination of the superintendent of the defendant town's Sign Bureau to conduct an in-court demonstration in order to show the sign would not have fallen when struck by a "human blow," as alleged. Counsel struck a model pole sharply with his hand. The sign was not unseated. The pole used was not the pole involved, nor was it identical to the pole as it was some four feet shorter than the original pole and was embedded in a movable concrete block rather than in stationary blacktop. The Court of Appeals held "the trial court did not abuse it's discretion in permitting the demonstration even though, the conditions in the courtroom were not substantially similar to those at the scene of the accident." Id. at 641. This ruling was based in large part upon the unrestricted opportunity afforded plaintiff's counsel upon cross-examination of the witness. This allowed an effective exploitation of the

dissimilarities between the model and the original which allowed counsel to minimize the significance to be attached to the demonstration. Id. Similar rationale was invoked by the Eastern District of New York Federal Court in Veliz v. Crown Lift Trucks, 714 F. Supp. 49 (ED NY 1989). The court observed in Veliz: "Courts have recognized, however, that when accompanied by limiting instructions or testimony detailing the dissimilarities between the demonstration and actual conditions, it is not error to admit demonstrations that are substantially similar to, but do not mirror, the actual conditions involved … ."

When, however, the conditions and circumstances under which the demonstrations or experiments were conducted are "quite dissimilar to those prevailing at the time in question," the results generated are not admissible. Martin et al, New York Evidence Handbook (2d ed.) §4.4, at p. 150. Exclusion is mandated because such dissimilarities render the results relevance and utility questionable and there is high potential for prejudice inherent in allowing the jury to hear or view them.

Whether the conditions are "quite dissimilar" is a determination to be made by the trial court. Illustrative cases abound. However, each case presenting the issue is sui generis. Two cases, one criminal and the other civil, are nonetheless worth noting.

In People v. Cohen, 50 N.Y.2d 908 (1980), defendant was charged with shooting to death her estranged husband. She maintained that he had committed suicide. The People at trial sought to show that suicide was not present because the husband was shot in the head from a distance, a fact which negated suicide. The powder burns on the husband's head was the basis for this claim, the powder burns being associated with a shooting from a distance. To show this, the prosecution was permitted to introduce evidence of the result of test-firing the murder weapon at a live rabbit, which had been shaved and human hair placed over the skin to simulate the conditions on the husband's head. The court held the evidence was inadmissible due to the obvious substantial dissimilarity between the skin and tissue of the rabbit and that of a human victim. Reversing defendant's conviction, the court added that if the People sought at the retrial to once against admit the results, proof that there was a substantial similarity between rabbit skin and tissue and that of a human victim would be a necessary element of the foundation for admissibility. Id. at 910.

As to the civil action, the Third Department in Cramer v. Kuhns, 213 A.D.2d 131 (3d Dept. 1995), addressed the issue of substantial similarities in the context of a videotape of a demonstration. Plaintiff was a passenger on a motorcycle. She allegedly was injured when the motorcycle's side stand, which either dropped down or was left down by the operator of the motorcycle, failed to retract upon impact with the pavement, causing an accident. The videotape showed a person riding a motorcycle, similar to the one involved in the accident, with the side stand extended; the operator leaning the motorcycle to the left so that the stand contacted the pavement; and the stand repeatedly failed to retract. The court noted that the demonstrations were conducted upon concrete and jennite surfaces, and not asphalt (upon which plaintiff's accident occurred) and that asphalt and jennite "simply are not the same type of surface." Id. at 136. Upon these facts the court found the surfaces were too dissimilar such that the demonstrations were inadmissible. Of note, the court rejected plaintiff's argument that this difference in surface went to the weight, and not the admissibility of the demonstrations. Id. at 138.

Where substantial dissimilarities are present, the results of the demonstration or experiment may still be admitted when there is testimony that the dissimilarities do not impact the integrity of the demonstration as offered to prove a specific fact. Thus, in Bolm v. Triumph, 71 A.D.2d 429, 438-39 (4th Dept. 1979), the differences between the actual gas tank involved and the model gas tank used for the demonstration were disregarded as there was "credible evidence that the two tanks were the same in all significant respects."

One commentary has observed that when dissimilarities are present, they are likely to be tolerated by a court when the test conditions involved would make it more difficult for the proponent of the evidence to prove the proponent's point. Barker, supra, §11:18. Thomas is cited in support. Plaintiff had testified that from where he was sitting in defendant's bus, the bus had veered over the highway divider line right before the accident. The most effective way to impeach that testimony was to show by a demonstration that plaintiff could not have made that observation because of where he was sitting and his impaired vision. However, replicating the actual conditions under which the claimed observation was made was difficult because of all the matters that had to be taken into account, such as the weather conditions (rainy and misty), and the crowning of the road at the accident site. Taking into consideration these points, the First Department held the trial court should have admitted evidence of the results of the demonstration despite the conceded dissimilarities involved.

In sum, when the results of demonstrations and experiments are to be offered into evidence, a careful delineation of the conditions of the original event, occurrence or condition and the demonstration and experiment must be made and then those conditions compared. The comparison process involves determinations of similarities and dissimilarities of the conditions, and whether any dissimilarities should preclude admission in view of the similarities and any proffered testimony regarding the significance of the dissimilarities.

Lastly, it must be kept in mind the observation of the Court of Appeals in People v. Acevedo, 40 N.Y.2d 701, 704 (1976), that while demonstrations and experiments can "play a positive and helpful role in the ascertainment of truth, courts must be alert to the danger that, when ill-designed or not properly relevant to the point at issue, instead of being helpful they may serve but to mislead, confuse, divert or otherwise prejudice the purposes of the trial."

Michael J. Hutter is a Professor of Law at Albany Law School and is Special Counsel to Powers & Santola. He is currently serving as the Reporter to the Guide to NY Evidence as prepared by the Chief Judge's Evidence Guide Committee.